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MODULE III
Introduction to Process Integration
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1. Introduction
4. Open Ended Problem
2. Foundation Elements
3. Case Study
5. Acknowledgments
Outline
6. References
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TIER I
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1. Introduction
Texas A&M UniversityTexas A&M University
6Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
“Do your best; then treat the rest”
1. Introduction
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Pollution is an ongoing concern that has been addressed in many different ways, from no pollution control, end-of the-pipe treatment
(1970’s), Implementation of Reuse/Recycle (1980’s) up to
Process Integration. The focus of this module is to expose PI tools
for pollution reduction/elimination
1. Introduction
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What is Process Integration?
“It is a holistic approach to process design, retrofitting and operation which
emphasizes the unity of the process”
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
1. Introduction
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The use of PI methods started as early as 1970’s with Pinch Technology (Heat Integration) in order to optimize heat exchanger networks (HEN).
The moving force for mass integration was initially pollution control; El-Halwagi and Manousiouthakis (1989) proposed the use of mass exchange networks (MEN) in analogy to the previously studied HEN.
PI tools can be used in a variety of industries and with approaches as wide as those involving product distribution, life cycle assessment etc (research in these an other areas is currently on their way)
1. Introduction
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2. Foundation Elements
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2.1. Holistic approach of process integration
2.2. Relationship of process integration to process analysis
2.3. Overview of energy, mass and property integration
2. Foundation Elements
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Holistic: Emphasizing the importance of the whole and the interdependence of its parts. Concerned with wholes rather than analysis or separation into parts
Source : http://dictionary.reference.com
Heuristic: Of or constituting an educational method in which learning takes place through discoveries that result from investigations made by the student
2. Foundation Elements2.1 Holistic Approach of Process Integration
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Efficient use of resources and raw materials
Efficient use of energy
Pollution reduction
Process debottlenecking
Cost reduction
Other process operation issues
Process Integration can address a wide set of design issues such as:
2. Foundation Elements2.1 Holistic Approach of Process Integration
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• Traditional process design has been addressed by heuristic methods, based on experience or corporate preferences, in which unit operations equipment have been design individually.
• However little attention has been placed on the relationships with other parts of the process
• Process Integration as a holistic approach, looks at the Big Picture and the relationships among the different operations and equipment alternatives
2. Foundation Elements2.1 Holistic Approach of Process Integration
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In order to illustrate how Process Integration (PI) can aid in the design process an illustrative example is given we have 3 options for a chemical reactor in order to produce a chemical product, the options to choose from are:
Source : www.aiche.org/cep/ July 2001
2. Foundation Elements2.1 Holistic Approach of Process Integration
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Using a heuristic approach the “best” option will be a mechanically agitated vessel that produces a yield of 73.9% with a volume of 12m3; however is there any other way to improve the process?
2. Foundation Elements2.1 Holistic Approach of Process Integration
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17Source : www.aiche.org/cep/ July 2001
Two designs based on the same solution
2. Foundation Elements2.1 Holistic Approach of Process Integration
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Using PI tools the following solution was found, 96.9% yield and 9.93m3 of volume.
Two designs based on this solution are shown next; the benefits of using PI tools are evident.
However a thorough analysis of the answer to the problem must be carried out in order to find a feasible design based on the findings obtained using a PI approach
Source : www.aiche.org/cep/ July 2001
2. Foundation Elements2.1 Holistic Approach of Process Integration
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• In order to find solutions that include the relationship effects among the different options for a given design task, the engineer must use PI in order to find optimum answer to the problems at hand, therefore PI tools should be included in the process design structure. Seider, Seader and Lewin illustrate it as shown in the next slides, for a complete description of the design steps, referred to the above mentioned authors
• Process design is a dynamic process, always making sure that the solutions will agree with the constraints set by the stakeholders (management, governmental agencies, environmentalist groups, general public etc) and the process itself
2. Foundation Elements2.2. Relationship of Process Integration to Process Analysis
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Process Analysis
“Analysis of the process elements for individual study of performance, by
using mathematical models and computer simulators”
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements2.2. Relationship of Process Integration to Process Analysis
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Current Situation/Opportunity
(e.g. a new technology is developed etc)
Asses Primitive Problem
(Define the objective of the design task based on the identified opportunity)
Survey Literature
(Identify all sources of useful information for the process design, e.g. Handbooks etc)
Preliminary Data Base Creation
(Thermodynamic data, kinetics, toxicity etc)
Preliminary Process Synthesis, reactions,
Separation, T-P Change Operations,
Task Integration
Source : Product and Process Design Principles : Synthesis, Analysis, and Evaluation W D. Seider J. D. Seader, D.R. Lewin
Equipment Selection
(Assess different options for the given process using process simulators, spreadsheets, in house software etc)
Part I
2. Foundation Elements2.2. Relationship of Process Integration to Process Analysis
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Is the Gross Profit
Favorable?
Yes
No
Source : Product and Process Design Principles : Synthesis, Analysis, and Evaluation W D. Seider J. D. Seader, D.R. Lewin
Equipment Selection
(Assess different options for the given process using process simulators, spreadsheets, in house software etc)
Reject
Part I a Part II Part IV
2. Foundation Elements2.2. Relationship of Process Integration to Process Analysis
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Source : Product and Process Design Principles : Synthesis, Analysis, and Evaluation W D. Seider J. D. Seader, D.R. Lewin
Create Process Flow Sheet
Process Integration
Pilot Plant
Testing Modify Flow Sheet
Create Detailed
Data Base
Prepare Simulation
Model
Heat and Power Integration
Second Law Analysis
Separation Train Synthesis
Dynamic Simulation
Flow Sheet Controllability
Analysis
Qualitative Synthesis
Part I a
Part IIPart VIIs the Process
still Promising? Part IIIGo to I or I a
No Yes
2. Foundation Elements
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Detail Design, Equipment Sizing,
Capital Cost Estimation,
Profitability Analysis, Optimization
Part IV
Is the Process still Feasible?
Is the Process still Promising?
Startup Assessment (Additional Equipment, Dynamic Simulation)
Part I or I a
Yes
NoReject Part III
Reliability and Safety Analysis (HAZOP, Pilot
Plant Testing etc)No
YesWritten Report,
Presentation
Part IVFinal Design
(P&ID, Bids etc)Construction Startup
Operation
Source : Product and Process Design Principles : Synthesis, Analysis, and Evaluation W D. Seider J. D. Seader, D.R. Lewin
2. Foundation Elements2.2. Relationship of Process Integration to Process Analysis
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Designing a new plant, retrofitting a existing one, has several operations and for each operation different equipment options and configurations to choose from.
The main problem is that the number of alternatives can be unmanageable. If only heuristics are use for the design, the engineer will risk to miss the true optimal solution to the design problem. Moreover, a design solution for a given problem cannot be use for a different one, since the initial findings are tailored for a specific problem.
Using a PI approach, one can avoid this issue, due to the fact that its methodology can be applied to any problem. The PI methodology is composed of three key components
2. Foundation Elements2.2. Relationship of Process Integration to Process Analysis
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Process Integration
Process Synthesis
Process Analysis
Process Optimization
It defines what process units and how they should be interconnected
Analysis of the process elements for individual study of performance
Minimizing or maximizing a desired function, to find the best option
2. Foundation Elements2.2. Relationship of Process Integration to Process Analysis
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As it has seen, process analysis is a step within the PI methodology.
It is important to emphasize that PI will look at the generalities rather than into the details, and then the designer can analyze the performance of the solutions in order to optimize his/her findings.
The following chart illustrate the impact of the process design steps over the budget
Process Conceptual Detailed Plant Detail Construction Startup &
Develop Design Design Layout Mech. Commission.
Impact
Committed
Spent$
Preliminary equipment selection
Equipment required during
design
2. Foundation Elements2.2. Relationship of Process Integration to Process Analysis
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Mass Integration
“Systematic methodology that provides a fundamental understanding of the global flow of
mass within the process and employs this holistic understanding in identifying performance targets
and optimizing the generation and routing of species throughout the process”
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
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•Mass Exchangers:
A mass exchanger is any direct-contact mass transfer unit that employs a MSA (Mass Separation Agent), to remove selectively certain component (e.g. pollutant) from a rich phase (e.g. waste stream).
The MSA should be partially or totally immiscible in the rich phase
Mass
Exchanger
Outlet Composition
yiout
Rich (Waste) Stream, Flow rate: Gi Inlet Composition
yiin
Lean Stream (MSA) Flow rate: Lj Inlet Composition
xjin
Outlet Composition
xjout
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1 Mass Exchangers
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When the two phases are in intimate contact the solutes are distributed between the two phases which leads to a depletion of solute in the rich phase and enrichment of the lean phase until equilibrium is reached. The difference in chemical potential for the solute is the moving force for mass transfer (Temperature difference for heat transfer, Pressure difference for fluid movement etc)
Solute Transferred to lean phase
Rich
Phase
Lean
Phase
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.1 Mass Exchangers
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Mass Exchange involve the following operations: Only counter current operations will be consider because of their higher efficiency
Adsorption
Absorption
Extraction Ion Exchange
Leaching
Stripping
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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Adsorption:Separation of a solute from a liquid or gaseous stream by contacting the carrying phase with a small porous solid particles (adsorbent), usually
arranged in a packed bed. The adsorbent can be regenerated by desorption using inert gas, steam etc
Source : Université d’Ottawa / University of Ottawa - Jules Thibault
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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In order to select an adsorption column the designer must select a suitable adsorbent for the given solute by looking at the appropriate
isotherm data as shown in the plot for a given set of process operation
Source : Université d’Ottawa / University of Ottawa - Jules Thibault
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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Absorption:A liquid solvent is place in contact with a gas containing a solute to be remove by taking advantage of the preferential solubility of the liquid. Reverse absorption is also know as
stripping (separation of a solute using a gas stream from a liquid phase)
Source : Université d’Ottawa / University of Ottawa - Jules Thibault
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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Liquid Extraction:It employs a liquid solvent to remove a solute from another liquid by using the
preferential solubility of the solvent to the solute in the MSA
Source : Université d’Ottawa / University of Ottawa - Jules Thibault
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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Leaching:Selective separation of some constituents
within a solid by contact with a liquid solvent
Solvent Solid
Mixing
SlurryOverflow Solution
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
Source : University of Ottawa - Jules Thibault
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Ion Exchange:Cation/anion resins are used to replace undesirable anions
from a liquid phase by non hazardous ions
NaCaRRNaCa 222
Water softeners
Cause of scale forming impurities
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
Source : Université d’Ottawa / University of Ottawa - Jules Thibault
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The mass exchanger is used to provide appropriate contact of the lean and rich phase; there are two principal categories of mass exchange units:
- Multistage (e.g. tray columns, mixer settlers etc), they provide intimate contact follow by phase separation
- Differential (e.g. packed columns, spray towers and mechanically agitated units), continuous contact between phases without intermediate separation and re-contacting
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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39Heavy Phase Out
Heavy Phase In
Light Phase In
Light Phase Out
Perforated Tray
Shell
Waste In
Waste Out
MSA Out
MSA In
Multiple Mixers / Settlers
Multistage Contactors
Tray Column
2. Foundation Elements
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Heavy Phase In
Light Phase In
Heavy Phase Out
Light Phase Out
Spray Column
Heavy Phase In
Light Phase In
Light Phase Out
Mechanically Agitated Mixer
Mixer
Heavy Phase Out
Differential / Continuous Contactors
2. Foundation Elements
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Equilibrium:
When a rich phase in a solute is put in contact with a lean phase transfer of the solute to the lean phase occurs, also part of the solute In the lean phase also back transfer to the rich phase.
At first the rate of solute being transfer from the rich phase is bigger than the rate of solute back transfer from the lean phase. However when the concentration of solute in the lean phase increases, the back transfer rate also increases.
Eventually the mass transfer rate and the back transfer rates become equal and an equilibrium is reached
Solute in the rich phase
Equilibrium distribution
function
Maximum attainable composition in the
lean phase
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
)( *jji xfy (1)
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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In environmental applications the engineer will find very often, diluted systems which can be linearized over the operating range to yield:
Special cases, Raoult’s Law for absorption
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
Partial pressure at
T
Mol fraction of solute in
gas
Mol fraction of solute in
liquid
jjji bxmy *(2)
*)(j
Total
soluteo
i xP
TPy (3)
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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Henry’s Law for stripping
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
Mole fraction of solute in
gas
Mol Fraction of solute in
stripping gas
Liquid phase solubility of pollutant at temperature
T
*jji xHy (4)
)(
lub
TP
yPH
Soluteo
ilitySoiTotal
j (5)
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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For solvent extraction
Composition of pollutant in liquid waste
Composition of the
solvent
Distribution Coefficient
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
*jji xKy (6)
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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The following relationships are used to size multistage mass transfer exchangers:
1 2 NN-1
XJ,0= Xjin
Lj
XJ,2 XJ,N-2 XJ,N-1 XJ,N= XJoutXJ,1
yi,1= yiout yi,N-1yi,3
yi,2 yi,N
yi,N+1= yiin
Gi
Overall Mass Balance:out
jjout
iiin
jjinii xLyGxLyG (7)
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
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Rearranging (7):
)(
)(in
jout
j
outi
ini
i
j
xx
yy
G
L
(9)
Eq. (8) represents the operating line in a McCabe-Thiele diagram:
LJ / Giyiin
yiout
xJin xJ
out
Theoretical stages
1
2
Equilibrium Line
Operating Line
)()( inj
outjj
outi
inii xxLyyG (8)
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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•The number of stages for a multistage unit can also be calculated with the following equations, with NTP being the number of theoretical plates
ij
j
jin
jjout
i
jin
jjini
j
ij
Gm
L
bxmy
bxmy
L
Gm
NTP
ln
1ln
(10)
j
ij
ij
iout
jout
i
outj
ini
ij
j
L
Gm
Gm
L
xx
xx
Gm
L
NTP
ln
1ln *
*
(11)
j
jiniout
j m
byx
* (12)
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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(13)
NTP
ij
j
jin
jjout
i
jin
jjini
Gm
L
bxmy
bxmy
oNTPNAP / (14)
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
When the contact time for each stage is not enough to reach equilibrium, the number of actual plates (NAP) can be calculated using contacting efficiency
Stage efficiency can be define on the rich or lean phase, for the rich phase we have:
Texas A&M UniversityTexas A&M University
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11ln
1ln
j
ijy
j
ij
jin
jjout
i
jin
jjini
j
ij
L
Gm
L
Gm
bxmy
bxmy
L
Gm
NTP
(15)
xx
yy
NTUHTUH
NTUHTUH
(16)
(17)
Based on rich phase
Based on lean phase
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
For differential (continuous) mass exchangers, the height is calculated using:
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For mass exchangers with linear equilibrium:
meanii
outi
ini
yyy
yyNTU
log*)(
(18)
)(
)(ln
)()()( *
jin
jjout
i
jout
jjini
jin
jjout
ijout
jjini
ii
bxmy
bxmy
bxmybxmyyy (19)
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
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For mass exchangers with linear equilibrium (cont):
meanjj
outj
inj
xx
xxNTUx
log*)(
(20)
j
jout
iinj
j
jiniout
j
j
jout
iinj
j
jiniout
j
meanjj
m
byx
m
byx
m
byx
m
byx
xx
ln
)( log*
(21)
2. Foundation Elements
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j
ij
j
ij
jin
jjout
i
jin
jjini
j
ij
L
Gm
L
Gm
bxmy
bxmy
L
Gm
NTP
1
1ln(22)
In order to calculate the diameter of the column (m) we have:
(23)
)(
)(4min MASVA
VFRAD
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
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In order to calculate the diameter of the column we need volumetric flow rate of air (VFRA), maximum allowable superficial velocity of air (MASVA):
air
airwatersmMASVA
068.0)/(
(24)
AFCAOCTAC (25)
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
To complete the design of a mass exchange unit, the designer has to look into the costs that the unit will have. The total annual cost (TAC) is given by:
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Where AOC is the annual operating cost and AFC is the annual fixed cost of the unit. Recall equation (8)
yiin
yiout
xJin,max xJ
outxJin*
JEquilibrium
Line
Operating Line
The number of mass exchange units will be higher for a small , a vanishing driving force. Therefore, it is necessary to assign a minimum driving force between the two lines
Driving Force
Lean End of Exchanger
2. Foundation Elements
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We have:
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
jjin
jjout
j bxmy )(min. (26)
By using a minimum allowable composition difference, J the designer can identify the minimum practically feasible outlet composition of the waste stream
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yiin
yiout
xJin xJ
out,max xJout*
J
Equilibrium Line
Operating Line
The number of mass exchange units will be higher for a small , a vanishing driving force. Therefore, it is necessary to assign a minimum driving force between the two lines
Driving Force
Rich End of Exchanger
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
Remainder :An outlet composition on
the equilibrium line = infinite number of stages
2. Foundation Elements
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We have:j
j
jin
joutj m
byx
max.
(27)
Where, J is the “minimum allowable composition difference” and xJ
out,max is the maximum practically feasible outlet composition of the MSA which satisfies the J driving force
As can be seen from (16 to 19) and (27), there is a trade off between the driving force and the cost/size of the equipment to be use for the separation. To illustrate the use of the previous equations a example is given
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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Example 1
Air stripping is used to remove 95% of the rich trichloroethylene (TCE, molecular weight = 131.4) dissolved in a 200kg/s (3180gpm) waste water stream. The inlet composition of TCE in the waste water is 100ppm. Air (free of TCE) is compressed to 202.6 kPa (2at) and diffused through a packed stripper. The TCE-laden air exiting the stripper is fed to the plant boiler which burns almost all the TCE.
Physical Data:
The stripping operation takes place isothermally at 293K and follows Henry's law. The equilibrium relation for stripping TCE from water is theoretically predicted using:
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
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Where yi is the mass fraction of TCE in waste water and xJ is the mass fraction of TCE in air. The air-to-water ratio is recommended by the packing manufacturer to be:
24 m3Air / m3water
Stripper Sizing Criteria:
The maximum allowable superficial velocity of waste water in the column is taken as 0.02m/s (approximately 30 gpm/ft2).The overall height of transfer unit based on the liquid phase is given by:
HTUy = Superficial Velocity of waste water/Kya
jj xy 0063.0 (28)
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
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Where ky is the water-phase overall mass transfer coefficient and a is the surface area per unit volume of packing. The value of Kya is provided by the manufacturer to be 0.002s-1
Cost Information:
The operation cost for air compression is basically the electricity utility needed for the isentropic compression. Electric energy needed to compress air may be calculated using: Compression Energy (CE)
11
)/(
1
in
out
isentropicair
in
P
P
M
RTkgkJCE
(29)
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
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The isentropic efficiency of the compressor is 60% and the electric energy cost is $0.06/kWhr. The system is operated for 8000hr/y. The fixed cost, $, of the stripper (including installation and auxiliaries, but excluding packing) is given by:
Fixed cost of column = 4700HD0.9
Where H is the height of the column (m) and D is the diameter (m). The cost of packing is $700/m3. The fix cost of the blower, $, is 12000LJ
0.6, where LJ is the flow rate of air (kg/s). Assume negligible salvage value and a five year linear depreciation. (a) estimate the column size, fixed cost and annual operating cost. (b) Due to the potential error in the theoretically predicted value of Henry’s coefficient, it is necessary to asses the sensitivity of your results to variation
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
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of the value of Henry’s coefficient. Plot the column height, annualized fixed cost and annual operating cost versus the relative deviation from the nominal value, for 0.5 2.0. The parameter is define by:
= Value of Henry’s Coeffcient/0.0063
(c) Your company is planning to undertake extensive experimentation to obtain accurate values of Henry’s coefficient that can be used in designing and evaluating the cost of this stripper. Based on your results, what would you recommend regarding the undertaking of these experiments?
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements
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63Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
Waste Water Gi = 200kg/s yi
in = 10-4
yiout = 5*10-6
Air, LJ = ? xJ
in = 0
xJout = ?
StripperBoiler
Exhaust Gas
Stripping of TCE from
Wastewater
Blower
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
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Solution: (a)
1. We will first have to calculate the flow and concentrations of the different streams as follows:
33 412.2
293082057.0
29*2
m
kg
KkgmolK
atmmkgmolkg
atm
RT
PM airAir
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
s
kgAir
kgWater
m
s
kgWater
Waterm
Airm
m
kgLi 06.12
1000
1*200*
125*412.2
3
3
3
3
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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Solution: Continuation
Using the overall mass balance equation we have:
ppmx
airkgmolphenolkgmolx
x
outJ
outJ
outJ
1575
/00157.0
0
10*510*1
200
06.12 64
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2. We now will calculate the height and diameter of the column, superficial velocity of waste water (SVWW)
aKSVWWHTU yy /
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Solution: Continuation
mssm
HTU y 102.0
02.0
1
meanii
yyy
NTUlog
*)(
5100
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)0*0063.010*5()00157.0*0063.010*1(
ln
)0*0063.010*5()00157.0*0063.010*1()(
6
4
64
log*
meanii yy
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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Solution: Continuation
ppmyy meanii 43.2910*943.2)( 5log
*
mH 228.3228.3*1
228.343.29
5100
yNTU
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mD 568.3)02.0(
)1000/200(4min
2. Foundation Elements
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Solution: Continuation
3. With the equipment dimension we can proceed to calculate the operating and fixed costs
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
kgkWhrkJ
kWhr
kg
kJ/10*788.1$
1
06.0$*
3600
1*31.107 3
kgkJkgkJCE /31.10711
2
6.0*29
293*314.8
14.1
4.1)/(
4.1
14.1
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.1. Mass Exchangers
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Solution: Continuation
Annual Operating Cost (AOC):
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2.455,53$)06.12(12000
8.592,22$$
700*228.3*)568.3(*4
5.666,47$)568.3*228.3(4700
6.0
32
9.0
Blower
mmmPacking
Stripper
yearyear
hr
hr
s
s
kg
kg
kJAOC /8.234,621$
8000*
13600*06.12*31.107
Equipment Cost (EC):
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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Solution: (b) (c)
Henry’s Law coefficient will affect the FC through the change in the size of the system. By changing one can find different values of Henry’s Law coefficient and use them to calculate the size of the column and then the FC; we will use Excel for this procedure. Since we have a linear 5 year depreciation the FC will be divided by 5
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
5.714,123$2.455,538.592,225.666,47 FC
Solution: Continuation
Fixed Cost (FC):
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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Alfa Henry H AFC TAC
0.5 0.00315 3.107112 24214.47 645449.3
0.75 0.004725 3.166444 24472.71 645707.5
1 0.0063 3.228434 24742.51 645977.3
1.25 0.007875 3.293275 25024.73 646259.5
1.5 0.00945 3.36118 25320.28 646555.1
1.75 0.011025 3.432384 25630.19 646865
2 0.0126 3.507149 25955.6 647190.4
Solution: Continuation
As the plot and Table 1 show, there is a small change in the TAC and AFC with changing Alfa, meaning that we don’t have appreciable savings by changing the height of the column with more accurate values of Henry’s Law coefficient. Therefore the project is not required; we just saved our company a lot of money!!!!
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchangers
0
100000
200000
300000
400000
500000
600000
700000
0 0.5 1 1.5 2 2.5
AFC
TAC
Very slight change
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Mass Exchange Networks
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchange Networks
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchange Networks
Mass Separation
Agents (MSA)
They are Lean Streams (Ns), LJ, j = 1, 2…Ns
Use to remove pollutants from rich
streams, NR
Process MSA, NSP
Low cost or almost free“In plant”
External MSA, NSE
Must be bought externally
•MSA can be:
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchange Networks
Flow rates, stream concentration and target concentration of rich streams are known, Gi, yS
S, yit
Inlet compositions of lean streams are also known, xJS flow rate of
lean streams, LJ, is to be determine to minimize network cost
Ns = NSP + NSE(28)
LJ LJC J = 1, 2…NSP
LJC is the flow rate of the Jth MSA available in the plant
(29)
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchange Networks
Waste streams can be
Disposed
Forwarded to processSinks (equipment)For recycle/reuse
Comply with Environmental
Regulations
Target compositionis the constraint
imposed by processSink
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• Target composition are assigned by designer based on the following constraints:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchange Networks
Physical (e.g. maximum
Solubility of pollutantIn MSA)
Technical (e.g. avoid corrosion,
Viscosity)
Environmental(e.g. EPA, OSHA
Regulations)
Safety(e.g. stay away of
Flammability limits)
Economic(e.g. optimize cost
Of MSA regeneration)
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• The following questions will arise:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchange Networks
Which ME operation should we use?
Which MSA should be selected?
How to match MSAs
to the waste streams?
What is the optimum
configuration?
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• The previous questions will result in a unmanageable number of combinations
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1. Mass Exchange Networks
• A systematic approach is required
“Targeting Approach”
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Targeting Approach
“It is based on the identification of
performance targets ahead of design and
without prior commitment to the final network
configuration”
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
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Minimum cost of MSA: By combining thermodynamic aspects of the problem with cost data of the MSA, the designer can identify the minimum cost of the separation, without designing the network
Minimum number of mass exchange units: This objective is aim at minimizing fixed cost of the system, by doing so, one can reduce pipe work, foundations, maintenance and instrumentation
GENERALLY
INCOMPATIBLE
2. Foundation Elements
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U = NR + Ni
U = Number of units
Ni = Number of independent synthesis sub-problems in which original synthesis problem can be subdivided
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.1.1. Mass Exchangers
(30)
• In most cases there will be only one independent synthesis problem. In order to avoid the incompatibility of the two targets, one have to use techniques that will identify the MOC solution and then minimize the number of exchangers that satisfy the MOC (Minimum Operating Cost)
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• In order for the separation to be feasible one have to work in the feasibility area• To relate the different concentrations in one scale, we need to use Equation (27)
yiin
yiout
xJin xJ
out,max xJout*
J
Feasibility area
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
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2. Foundation Elements
• In order to minimize the cost of external MSA one must maximize the use of in plant MSA
2.3. Overview of Mass, Energy and Property Integration2.3.1.1. Mass Exchangers
• The pinch diagram is a graphical representation that considers the thermodynamic constraints of the system, calculate MR with:
y x1
x2
Pinch Point
Mass Exchanged
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
R
ti
siii
Ni
yyGMR
,....,2,1
)(
(31)
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How to construct the pinch diagram?
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
1. Represent each stream with an arrow
2. Plot mass exchanged versus its composition
3. Tail of the arrow is the supply composition and head is target composition
4. The slope is the flow rate of the stream
5. The vertical distance between the tail and the head represent the amount of pollutant transferred ( MRi ) from the rich stream ( yi ) to the lean stream
y1t y2
t y1s y2
s
MRi
yi
6. Stack the arrows on top of one another starting with the one with the one having the lower composition
R1
R2
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How to construct the pinch diagram?
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
7. Obtain the composite diagram by using the “diagonal rule”
8. The vertical axis is a relative scale, one can move up and down the curves while maintaining constant the vertical distance
9. Apply the same procedure for the lean streams
y1t y2
t y1s y2
s
MRi
MR2
MR1
yi
10. Plot both composite curves in one graph, slid the lean composite until it touches the rich (waste) composite stream
R1
R2
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2. Foundation Elements
How to construct the pinch diagram?
2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
11. Use the above equation to obtain the horizontal scale and Equation 33 to calculate MS
x1s x1
t
MSiMS2
MS1
yi
x2s x2
t
S1
S2
jj m
byx
1
1
(32)
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2. Foundation Elements
How to construct the pinch diagram?
2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
x1
yi
x2
Rich Composite Stream
Lean Composite Stream
SP
sj
tj
cjj
Nj
xxLMS
....,2,1
)(
(33)
Excess Capacity of Process
MSA’s
Load to be removed by
external MSA’s
Mass Exchanged
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2. Foundation Elements
How to construct the pinch diagram?
2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
x1
Mass Exchanged
yi
x2
Rich Composite Stream
Lean Composite Stream
Pinch Point
Integrated mass exchange:
Maximum amount of pollutant that can be transfer
•The Pinch point is the minimum feasible concentration, it is also a bottleneck, slid up or down the composite curves until they touch, keeping the vertical distance and the concentrations
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• In order to reduce the excess capacity of process MSA one can either reduce flow rate, or composition. Care must be given when choosing , since it will cause the lean composite curve to move to the right, increasing the load to be removed by external MSAs
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
Load of pollutant above the pinch to
be removed
)( supplyj
outjjj xxLS (34)
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
In the case that 2 or more MSAs are overlapped, one have to calculate the composition that will suit the requirements of the plant and compare the costs in order to identify the MSA that will be use in the separation
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• To calculate cost of recirculation MSA (Cj) and cost of removed pollutant (cj
r) use:
2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
Cost of Make up
MSA ingrecirculat /$ kgCRCMC j (35)
Cost of Regeneration
pollutant removed of kg/$)(
s
jt
j
jrj
xx
Cc (36)
2. Foundation Elements
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• There are cases when there are no process MSAs, therefore a different approach is required in order to construct the pinch diagram
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
x1
MR
yi
x2
Rich Composite Stream
x3
S1
S2
S3
1. Draw the rich composite as before
2. Draw the external MSA as Sj arrows with the tail as the supply composition and the head its target composition
3. Calculate the cj
4. If arrow S2 lies completely to the left of S1 and c2
r < c1r then
eliminate S1
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.1.1. Mass Exchangers
x1
MR
yi
x2
Rich Composite Stream
x3
S1
S2
S3
5. If arrow S3 lies completely to the left of S2 but c3
r is > c2r then retain
both MSAs6. In order to minimize the
operating cost of the network one should use the cheapest MSA where it is feasible
7. In this case S2 should be used to remove all the rich load to the left and the remaining load is removed by S3
8. Calculate flow rates of S2 and S3 by diving the rich load remove by the composition difference for the MSAs
9. Construct the pinch diagram as shown
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Example 2A process facility converts scrap tires into fuel via pyrolisis. The discarded tires are fed to a high temperature reactor where heat breaks down the hydrocarbon content of the tires into oils and gaseous fuels. The oils are further processed and separated to yield transportation fuels.
The reactor off gasses are cooled to condense light oils. The condensate is decanted into two layers: organic and aqueous. The organic layer is mixed with the liquid products of the reactor
The aqueous layer is a waste water stream whose organic content must be reduce prior to discharge. The primary pollutant in the waste water is a heavy hydrocarbon. The data for the waste water stream is given in the next slide. A process lean stream is a flare gas (a gaseous stream fed to the flare) which can be used as a process stripping agent. To prevent back propagation of fire from the flare, a seal pot is used.
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
Stream Description Flowrate
Gi
kg/s
Supply Composition
(ppmw)
yis
Target Composition
(ppmw)
yit
R1 Aqueous layer from decanter
0.2 500 50
Table 1
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Example 2, ContinuationAn aqueous stream is passed though the seal pot to form a buffer zone between the fire and the source of the flare gas. Therefore, the seal pot can be used as a stripping column in which the flare gas strips the organic pollutant off the waste water while the waste water stream constitutes a buffer solution preventing back propagation of fire. Three external MSAs are considered: a solvent extract S2, an adsorbent S3 and a stripping agent S4. The equilibrium data for the jth MSA and the process MSA are given in the next slide, the equilibrium data is given by
yi = mjxj
Where yi and xj are the mass fractions of the organic pollutant in the waste water and the jth MSA, respectively. Use the pinch diagram to determine the minimum operating cost of the MEN
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
Stream Upper Bound on flow rate
Ljc
kg/s
Supply composition
(ppmw)
xsJ
Target Composition
(ppmw)
xJt
mJ JCJ
$/kg
MSA
S1 0.15 200 900 0.5 200 -
S2 300 1000 1.0 100 0.004
S3 10 200 0.8 50 0.030
S4 20 600 0.2 50 0.050
Table 2
Example 2, Continuation
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
Example 2, Continuation
Condenser
Decanter
Separation Finishing
Seal Pot
Flare
Shredded Tires
Reactor Off Gases
Light oil
Waste water R1
Gaseous Fuel
Water
To atmosphere
To waste water
Liquid Fuel
Flare Gas S1
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
PyrolisisReactor
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
Solution
Condenser
Decanter
Separation Finishing
MEN
Flare
Shredded Tires
Reactor Off Gases
Light oil
Waste water R1
Gaseous Fuel
To atmosphere
To waste water
Liquid Fuel
Flare Gas, S1
S2 S3 S4
PyrolisisReactor
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2. Foundation Elements
Solution, ContinuationCalculate and plot the pinch diagram, using Equations 31,32,33 and Tables 1 and 2
Pinch Diagram
0
50
100
150
200
0 100 200 300 400 500 600
2.3. Overview of Mass, Energy and Property Integration
2.3.1.1. Mass Exchangers
Mass Exchanged10-6
y. ppmw
MR y
R1
0 50
90 500
S1
0 200
105 550
MR y
R1
0 50
90 500
S1
90 200
195 550
S1
R1
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Pinch Diagram
0
20
40
60
80
100
120
140
0 100 200 300 400 500 600
2. Foundation Elements
Pinch Point
Excess Capacity of Process MSA
Integrated Mass
Exchanged
Mass to be Removed by External MSA
Mass Exchanged 10-6
y. ppmw
New S1 Target Composition
Solution, Continuation
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• From the pinch diagram the load to be removed by the process MSA is 64 x 10-6 kg/s, the excess capacity is 45 x 10-
6 kg/s; we have to use the whole flare gas flow rate to remove pollutant from the waste water, due to the fire hazard that it represents (we cannot by pass part of it directly to the flare, in order to reduce the excess capacity) from a mass balance or the pinch diagram we find the outlet composition of S1 to be: 400 ppmw
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
Solution, Continuation
• We now have to evaluate the different external MSAs. The load to be removed by external MSA is approximately 31 x 10-6 kg/s, we need to check the thermodynamic feasibility of each external MSA
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2. Foundation ElementsSolution, Continuation
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Pinch Diagram
0
50
100
150
200
0 100 200 300 400 500 600
2. Foundation Elements
Mass Exchanged 10-6
y. ppmw
Solution, Continuation
S2S3S4
1000300200
48
60020
10
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• Calculating the costs of each separation agent, using Equation 36:
c2r = 5.714 $/kg
c3r = 157.89 $/kg
c4r = 86.20 $/kg
Solution, Continuation
2. Foundation Elements
Analysis: S2 is not a feasible MSA since its target concentration is higher that the target concentration of the rich stream therefore mass transfer is not possible. S4 is the selected MSA, flow is 31x10-6kg/s annual operating cost is 31x10-6x86.2x3600x24x365 = $84,270.5/yr
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• Process integration is conformed of mass and energy integration
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.2. Targeting rules
Process
Energy In
Energy Out
Mass In Mass Out
• In order to achieve a good mass integration, one has to set targeting goals; from an overall mass balance:
Depletion Out Mass Generation In Mass (37)
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• In order to reduce intake of fresh resources and reduce the discharge of waste streams one need to consider recycle, mixing, segregation and/or interception. In order to identify the recycle (direct or after segregation/interception) strategy that will have a net effect on the system the following procedure follows
2.3. Overview of Mass, Energy and Property Integration
2.3.1.2. Targeting rules
2. Foundation Elements
1
2
53
4
Fresh Load Terminal Load
FLk,1
FLk,2
FLk,1
TLk,1
TLk,2
TLk,3
TLk,4No Recycle
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• Identify where recycle of streams will have the biggest net effect
2.3. Overview of Mass, Energy and Property Integration
2.3.1.2. Targeting rules
2. Foundation Elements
1
2
53
4
Fresh Load Terminal Load
FLk,1
FLk,2
FLk,1
TLk,1 + Rk,2 – Rk,1
TLk,2 - Rk,2
TLk,3
TLk,4
No Net effect = Poor Recycle
+ Rk,1
1,1,2,2, kkkk RRRR
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2.3. Overview of Mass, Energy and Property Integration
2.3.1.2. Targeting rules
2. Foundation Elements
1
2
53
4
Fresh Load Terminal Load
FLk,1 – Rk,2
FLk,2 – Rk,1
FLk,1
TLk,1 – Rk,1
TLk,2 – Rk,2
TLk,3
TLk,4
Effective Recycle from Terminal Streams
1,2, kk RR 1,2, kk RR
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2.3. Overview of Mass, Energy and Property Integration
2.3.1.2. Targeting rules
2. Foundation Elements
1
2
53
4
Fresh Load Terminal Load
FLk,1 – Rk,2
FLk,2 – Rk,1
FLk,1
TLk,1 – Rk,1
TLk,2 – Rk,2
TLk,3
TLk,4
Effective Recycle from Terminal and Intermediate Streams
1,2, kk RR 1,2, kk RR
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• Recycle of streams must comply with sink constraints; such as composition and flow rate which a sink can take. In order to take advantage of direct recycle opportunities within a plant one has to identify them by using a graphical technique know and the source/sink mapping diagram
2.3. Overview of Mass, Energy and Property Integration
2.3.1.2. Targeting rules
2. Foundation Elements
Sink
Source
• Effective recycle should connect fresh intake and out streams
Pollutant Composition
Flo
w R
ate
Lo
ad
,
kg
/s
Acceptable Flow Range
Acceptable Composition
Range
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• The interception of the two constraints is the area where any source within it can be recycled directly to the sink
2.3. Overview of Mass, Energy and Property Integration
2.3.1.2. Targeting rules
2. Foundation Elements
Sink
Source
• The maximum amount to be recycle is the minimum between the fresh inlet and outlet load. In order to recycle b and c use the mixing arm rule
• Direct recycling does not require new equipment
• Define equipment constraint from, technical data, operation conditions, physical and chemical properties etc
S
Pollutant Composition
Flo
w R
ate
Lo
ad
, k
g/s
a
b
c
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2. Foundation Elements
• Arm rule:
2.3. Overview of Mass, Energy and Property Integration
2.3.1.2. Targeting rules
Pollutant
Composition
Flow Rate
Load, kg/s
Arm c Arm b
yb ys yc
Fs
Fb
Fc c
bSources
Resulting Mixture
bc
bbccs
cbs
FF
yFyFy
FFF
• If a fresh source is mixed with a polluted one, in order to minimize the use of fresh one has to minimize fresh arm
(38)
(39)
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2. Foundation Elements
• Note:
2.3. Overview of Mass, Energy and Property Integration
2.3.1.2. Targeting rules
1. The previous method can be simplified for a complex plant since no all equipment will required fresh utilities or discharge waste streams. We will identify those that do and apply the previous method
2. Identifying equipment constraints can reduce fresh and waste streams with little process modifications, by working with minimum requirements
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2. Foundation Elements
• The Composition-Interval Diagram (CID)
2.3. Overview of Mass, Energy and Property Integration
2.3.1.3. Synthesis of MEN, Algebraic Approach
The pinch diagram is a very useful tool, however it has accuracy limitations common to any graphical method, therefore an algebraic approach that will overcome these limitations is presented
This diagram shows the mass exchanged between the different streams, thermodynamically feasibility and the location of the pinch point
The number of scales is equal to Nsp + 1, where Nsp is the number of lean streams. Each process is represented by a vertical arrow with supply and target compositions as the tail and head respectively. The horizontal lines are the composition intervals whose number is define as:
1)(2intervals SPR NNN (40)
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2. Foundation Elements
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• Within each interval it is possible to transfer mass from the rich stream to the lean stream and it is possible to transfer mass from the interval to any MSA that is in an interval below it
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.3. Synthesis of MEN, Algebraic Approach
Table of Exchangeable Loads (TEL)
• The TEL is used to determine the load of mass exchanged within each interval; for the waste stream the load is:
Wi,kR = Gi(yk-1 – yk) (41)
And the exchangeable load for the lean streams is:
Wj,kS = Lj
c(xj,k-1 – xj,k) (42)
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2. Foundation Elements
• Since one or more streams will pass through one or more intervals we can express the total load of the stream that passes through that interval k; for the waste and lean streams we have
2.3. Overview of Mass, Energy and Property Integration
2.3.1.3. Synthesis of MEN, Algebraic Approach
Skjkj
Sk
Rkiki
Rk
WW
WW
, interval through passes
, interval through passes
(44)
(43)
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2. Foundation Elements
• Note that mass can be transferred within each interval from a waste stream to a lean stream, as a result it is possible to transfer mass from a waste stream in a interval to a lean stream in a lower interval, the resulting mass balance is:
2.3. Overview of Mass, Energy and Property Integration
2.3.1.3. Synthesis of MEN, Algebraic Approach
interval theleaving and
enteringpollutant of mass residual theare ,1
1
kth
WW
kk
kSkk
Rk
(45)
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2. Foundation Elements
• The graphical representation is:
k
2.3. Overview of Mass, Energy and Property Integration
2.3.1.3. Synthesis of MEN, Algebraic Approach
KSkW
RkW
1k
Waste Recovered from Waste Streams
Mass Transferred to
MSA’s
Residual Mass from Preceding Interval
Residual Mass to Next Interval
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Note:• Initial residual mass for k = 0 is zero• The most negative value of the residual mass load
indicates the excess capacity of MSA’s, in order to reduce it, one can either reduce the flow rate, or the composition of the MSA’s, one this is done one needs to recalculate and apply the previous procedure. The pinch will be represented at the location when the residual mass is zero. This result will be equal to the one given by the pinch diagram
• After reducing flow rate or concentration, the remaining load is the load to be removed but external MSA’s
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2.3.1.3. Synthesis of MEN, Algebraic Approach
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Example 3
3
1)11(2
Intervals
Intervals
N
N
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.3. Synthesis of MEN, Algebraic Approach
A lean MSA will be used to reduce the composition of a rich stream, the data is give in the table
•Calculate the number of intervals
•Calculate the compositions of each stream for the y and x scales
•Prepare de CID diagram•Calculate a TEL table, using 41, 42•Calculate the cascade diagram, by 43,44
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2.3.1.3. Synthesis of MEN, Algebraic Approach
Composition Table
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.3. Synthesis of MEN, Algebraic Approach
CID Table
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.3. Synthesis of MEN, Algebraic Approach
TEL Table
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Cascade Diagram
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• The excess capacity of the MSA is 0.000027 kg/s of pollutant and the actual flow required for the separation is:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.1.3. Synthesis of MEN, Algebraic Approach
111.00002.00009.0
0.00002715.0
Capacity Excess
Flow Actual
tFlow Actual
L
xxLL
si
(45)
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• Recalculating the TEL and cascade diagram
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.3. Synthesis of MEN, Algebraic Approach
Pinch
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•The concentrations at which the pinch point is located are:
y = 0.00011x = 0.0002
The quantity leaving the bottom of the cascade diagram is the amount to be removed by external MSA’s, 0.00001 kg/s
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2.3.1.3. Synthesis of MEN, Algebraic Approach
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• In order to minimize the number of mass exchangers to obtain a MOC solution, we will decompose the design problem in to two sub-problems one above and one below the pinch
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.4. Synthesis of MEN, with Minimum Number of Exchangers
pinch below ,pinch below ,pinch below ,pinch below ,
pinch above ,pinch above ,pinch above ,pinch above ,
pinch below ,pinch above ,
iSRMOC
iSRMOC
MOCMOCMOC
NNNU
NNNU
UUU
(46)
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• By starting the synthesis of mass exchangers at the pinch point one can ensure that the options will not be compromised at later steps, due to the fact that the pinch point the all streams match at the minimum driving force . The matching of streams will be done in two sections, above and below the pinch, two criteria must be applied to ensure feasibility
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.5. Feasibility Criteria
RBelowLBelow
AboveLRAbove
NN
NN
(47)
(48)
Stream Population
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• If the previous inequalities do not hold with the rich and lean streams/branches then splitting of one or more of them is required, as before stream splitting might be required to comply with the following inequalities
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.5. Feasibility Criteria
Pinch Below
Pinch Above
ij
j
ij
j
Gm
L
Gm
L
(48)
(49)
Thermodynamic Feasibility
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• The following example will illustrate the procedure for network synthesis; given a process with two waste streams and two process MSA’s
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
Example 4
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• The composition for waste and lean streams are shown in the table
• Number of Intervals = 7
• Calculate the CID
• Calculate TEL
• Revise TEL
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
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• CID
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
• TEL
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2. Foundation Elements• Cascade Diagram
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• The excess load of the MSA’s is 0.00151kg/s; using Equation 45 and reducing the excess capacity of S2 we have an actual flow of 2.925 kg/s and a revise TEL and cascade diagram can be calculated, with its pinch point at interval 4 and compositions y, x1, x2 = 0.0165, 0.00725, 0.01, respectively
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
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2. Foundation Elements• TEL, revised
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• We will now define the number of mass exchangers• Define feasibility criteria• Match streams
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
2112
3122
pinch below ,
pinch above ,
MOC
MOC
U
U
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2. Foundation Elements• Cascade Diagram, revised Pinch Point
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• The following figure will aid during checking of the feasibility criteria
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
Pinch Point
R1
R2
S1
S2
G1 = 2.5 kg/s G2 = 1 kg/s L1/m1 = 2.5 kg/s L2/m2 = 1.95 kg/s
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
22
AboveLRAbove NN
Pinch Above ij
j Gm
L
Match:
R1 – S1
R2 – S2
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Mass Exchanged Loads
R1 = 0.08375 kg/sS1 = 0.03875 kg/sMass exchanged = 0.03875 kg/s
R2 = 0.0135 kg/sS2 = 0.0585 kg/sMass exchanged = 0.0135 kg/s
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
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•Remaining load from R1 = 0.045 kg/s•Excess capacity of S2 = 0.045 kg/s
Note that these values are equal, due to the fact that there is no mass transferred trough the pinch. Now we proceed to match exchangers represented by circles with streams; the mass exchanged appears within the circles and composition in arrows. Load to be removed by external MSA is 0.0155kg/s
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.1.6. Network Synthesis
R2 S1
S2R1
0.03875 0.03875
0.045
2.5 kg/s 0.05
0.0165
0.0135 0.0135
5 kg/s 0.015
0.00725
0.0451 kg/s 0.03
0.0165 0.01
R2 transfers all its load S1 is depleted
S2 can remove
load
R1 capacity not removed
by S1
x2 **x1 *
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• In order to calculate the intermediate compositions leaving exchanger R2 – S2 use a material balance using Equation 37:
x2 ** = 0.01 + 0.0135/3 = 0.0145
x1* = 0.05 - 0.045/2.5 = 0.032
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
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21 RBelowLBelow NN
•After completing the network design above the pinch we will proceed to do the same below the pinch
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.1.6. Network Synthesis
Pinch Point
R1 R2 S1 S3 External MSA
G1 = 2.5 kg/s G2 = 1 kg/s L1/m1 = 2.5 kg/s
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Checking feasibility (Eq. 49) determines that S1 has to be split in two since L1/m > Gi. There are many different combinations in order to achieve it, for this case we will split them arbitrarily and match the streams
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
Pinch Point
R1 R2S1 S3 External MSA
G1 = 2.5 kg/s G2 = 1 kg/s
L1= 5 kg/sL
12/m
1 =
0.7
25 k
g/s
L1
1/m
1 =
1.7
75 k
g/s
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Pinch Below ij
j Gm
L
Match:
R1 – S11
R2 – S12
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.1.6. Network Synthesis
• Mass Exchanged Loads
• R1 = 0.01625 kg/s• S11 = 0.0079875 kg/s• Mass exchanged = 0.0079875 kg/s
• R2 = 0.0105 kg/s• S12 = 0.0032625 kg/s• Mass exchanged = 0.0032625 kg/s
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.1.6. Network Synthesis
•Remaining load from R1 = 0.0082625 kg/s
•Remaining load from R2 = 0.0072375 kg/s
•In order to remove the remaining load from waste streams it is required to use external MSA’s (S3)
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Pinch Point
G1 = 2.5 kg/s G2 = 1 kg/s
L1= 5 kg/s
2. Foundation ElementsR1 R2
S1S3 External MSA
0.0079875 0.079875
0.0032625 0.0032625
0.0072375
0.00826250.0082625
0.0072375
Calculate the Intermediate Compositions
Can you Suggest another
Configurationfor S3?
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R2
S1
S2R1
0.03875 0.03875
0.0452.5 kg/s 0.05
0.0165
0.0135 0.0135
5 kg/s 0.015
0.00725
0.045
1 kg/s 0.03
0.01650.01
x2 **
x1 *
L1= 5 kg/s
0.0079875 0.079875
0.0032625 0.0032625
0.0072375
0.00826250.0082625
0.0072375
Pinch Point
Complete Network
S3
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Heat Exchange Networks
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2.3.2. Heat Integration
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• Every plant requires energy to be transfer from a hot stream to a cold one; hence the importance a proper heat exchange network in order to have a positive impact in the economics and operation of any process
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Heat Exchange Network
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Cold Streams In
Cold Streams Out
Hot Streams In
Hot Streams Out
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• To define the HEN (Heat Exchange Network) problem first we need to define the following:
A number of hot process streams that need to be cooled NH and a number of cold process streams that need to be heated NC, we need to synthesize a network that will achieve the transfer of heat at minimum cost
For hot streams the heat capacity can be expressed as:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
tu
su
uP
T
T
FC
eTemperaturTarget
eTemperaturSupply
Capacity Heat ,
(50)
For u = 1,2,…NH
2.3.2. Heat Integration
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In addition for the cold streams we have:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
tv
sv
vPf
t eTemperaturTarget
t eTemperaturSupply
c Capacity Heat ,
(51)
For v = 1,2,…NC
A number of cold and hot streams is available whose supply and target temperatures are known but not their flow rates. In order to design a HEN the following questions need to be answered:
2.3.2. Heat Integration
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Which heating/cooling utilities should be used
What is the optimal heat load to be
removed/added by each utility?
What is the
Optimal configurationHow should the hot and
Cold streams be matched?
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2.3.2. Heat Integration
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• In order to have heat transfer between two streams the following relationship will established a correspondence between the hot and cold streams temperature:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
minTtT (52)
2.3.2. Heat Integration
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• A special case of mass exchanged is the one that compares the heat exchanged problem corresponding T, t, Tmin with yi,xj and j respectively, and having mj, bj equal to zero
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HE
T
NOTE:The order of X and Y axis used here are different from what has been commonly used in the literature. The reason is that there is a strong interactions between mass and energy making the enthalpy expression non linear function of temperature therefore it is easier to have enthalpy in function of temperature, this specially important when combining mass and heat integration
T
H
HE vs. T Approach
T v. H Approach
T min
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2.3.2. Heat Integration
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• The procedure use to set up the pinch diagram is exactly the same as the one use for mass integration, by placing the hot and cold streams temperatures in the diagram, starting by their supply temperature as the tail of an arrow and the target temperature as the head of an arrow. The following equation can be used to calculate the vertical distance or heat loss by the hot stream
Source : Pollution Prevention through Process Integration, M. M. El-Halwagi
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
)(,tu
suuPuu TTCFHH (53)
2.3.2. Heat Integration
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• And for the heat gained by the cold stream we have:
• To construct the pinch diagram we have:
)(,sv
tvvPvv ttcfHC (53)
2.3.2. Heat Integration
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
T1t T2
t T1s T2
s T
HE
HH2
HH1
H1
H2
HE
HC2
HC1
C1
C2
t1t t2
t t1s t2
s T
t = T - Tmin
2.3.2. Heat Integration
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2. Foundation Elements
How to construct the pinch diagram?
2.3. Overview of Mass, Energy and Property Integration
Heat Exchanged
Hot Composite Stream
Cold Composite Stream
Thermal Pinch Point
Integrated Heat Exchange
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2.3.2. Heat Integration
T
t = T - Tmin
Minimum Heating Utility
Minimum Cooling Utility
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The analysis of the thermal pinch diagram is as follows:
• The cold composite curve cannot be slid down any further otherwise there will not be thermal feasibility, if the cold composite is moved up less heat integration is possible therefore more utilities are required
• Above the pinch there is a surplus of cooling and below the pinch there is a surplus of heating utilities
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.2. Heat Integration
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• A similar analysis as the one used for mass integration can be done in order to apply an algebraic cascade diagram, the number z of intervals is:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.2. Heat Integration
2)(2int CH NNN (54)
• To construct a Table of Exchangeable Heat Load TEHL we need:
)(
)(
1,,
1,,
zzvpzv
zzuPuzu
ttfcHC
TTCFHH
(55)
(56)
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• The collective total load for the hot and cold process streams are:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.2. Heat Integration
zvNv
vTotalz
zuNu
uTotalz
HCHC
HHHH
C
H
,,...2,1 wherez,
interval through passes
,,...2,1 wherez,
interval through passes
(57)
(58)
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• As it was mentioned for mass exchanged, it is feasible to transfer heat from a hot process stream to a cold one within each temperature interval, a heat balance around a temperature interval yields:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.2. Heat Integration
Z
TotalzHC
TotalzHH
1zr
Heat Added by Process Hot
Stream
Residual Heat from Preceding Interval
Residual Heat to Next Interval zr
Heat Removed by Process Cold
Stream
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2. Foundation Elements
• The resulting heat balance is:
2.3. Overview of Mass, Energy and Property Integration
2.3.2. Synthesis of MEN, Algebraic Approach
1 zTotalz
Totalzz rHCHHr
(59)
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• The resulting TID is:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.2. Heat Integration
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Property Integration:“Functionality based holistic approach to the
allocation and manipulation of streams and processing units which is based on tracking, adjustment, assignment and
matching of functionalities throughout the process”
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.3. Property Integration
Source : Property Integration: Componentless Design Technique and Visualization Tools
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• Component mass balances are an integral part of process design. There are several design problems in which the designer is interested in a group of properties such as viscosity, corrosion, density etc. Solvent selection is a clear example in which one is interested in its volatility, viscosity, equilibrium distribution, instead of its chemical constituents.
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration2.3.3. Property Integration
Source : Component less design of recovery and allocation systems: a functionality based approach
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• Property visualization tools are limited to 3 properties, an algebraic approach is used to deal with more complex cases. The advantage of visualization tools is based on the insides that give of the process, and how the design problem can be addressed. In order to apply this method to a set of properties we need to introduced the concept of cluster
• Properties are not conserved, as a result they cannot be tracked among units without using mass balances, the problem is that often is not possible to identify every single chemical species e.g. Gasoline, Dowtherm
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2.3.3. Property Integration
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Cluster
“Defines as condensed surrogate properties which can be used to characterize the
complex mixture and can be tracked my mapping the raw properties of infinite
compounds onto finite domains”
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2.3.3. Property Integration
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• The problem statement is: given a number of process streams Ns which contain the chemical species of interest, can be used in a number of sinks Nsinks (process units) in order to optimize a a desired objective e.g. minimize usage of fresh resources, maximize use of process resources, minimize cost of external streams etc. Each sink has a set of constraints defined as:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
maxsinmin
maxsin,min
RateFlowrateFlowRateFlow
propertypproperty
k
ki
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• Each stream can be characterized by Nc raw properties with a mixing rule that characterized a given stream
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
sisii
ths
siisNsii
pofOperatorp
rateflowtotaltheto
streamstheofoncontributiFractionalx
pxp s
,,
,1
)(
)()(
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(60)
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• pi,s can be normalized as:
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
refi
siisi
p
)( ,
,
• An augmented property index (AUP) for each stream s, is define as the summation of the dimensionless raw property operators:
s
siNis
Ns
AUP c
,...,2,1,1
(61)
(62)
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• Ci,s is the cluster for property i in stream s
2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
s
sisi AUP
C ,,
• For any stream s, the sum of clusters must be conserved adding up to a constant e.g. unity
s
sNi
Ns
Cc
,...,2,1
11
(63)
(64)
c
sisNsi
Ns
CC s
,...,2,1,1
(65)
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2.3.3. Property Integration
• The framework for allocation and interception for property integration is:
Property Integration
Network (PIN)
u = 1
u = 2
u = Nsinks
.
.
.
.
.
.
Processed Sources (back to process)
s =1
s =1
Sources Segregated Sources
Sinks
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2.3.3. Property Integration
• Consider a cluster of stream s to unit u, with three targeted properties i, j, k we have:
sj
sk
sj
sisksjsi
sjsj
si
sk
si
sjsksjsi
sisi
C
C
,
,
,
,,,,
,,
,
,
,
,,,,
,,
1
1
1
1
(66)
(67)
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
1
1
,
,
,
,,,,
,,
sk
sj
sk
sisksjsi
siskC
• In order to obtained an overestimation of the feasibility region we have:
max
min
max
minmax
,
,
,
,
,
1
1
si
sk
si
sj
siC
(68)
(69)
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
min
min
min
minmin
,
,
,
,
,
1
1
si
sk
si
sj
siC
max
min
max
minmax
,
,
,
,
,
1
1
sj
sk
sj
si
sjC
min
min
min
minmin
,
,
,
,
,
1
1
sj
sk
sj
si
sjC
1
1
max
min
max
minmax
,
,
,
,
,
sk
sk
sk
si
skC
(70)
(73)(71)
(72)
• In order to allocate, mix or intercept streams one needs to identify a feasibility region for the sinks, by using the following relationships:
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2.3.3. Property Integration
1
1
min
min
min
minmin
,
,
,
,
,
sk
sj
sk
si
skC (74)
• These points will now need to be plotted in a ternary diagram will be shown next
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2.3.3. Property Integration
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration Ci
CkCj
Ci,smax
Cj,smin
Cj,smax
Ck,smin Ck,s
max
Cj,smin
Overestimated Region
We need to find the true estimation of the feasibility region (for a more detailed explanation of how to obtained these results, review the references at the end of the module)
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration Ci
CkCj
True Region
),,( min,
min,
max, sksjsi
),,( min,
max,
max, sksjsi
),,( min,
max,
min, sksjsi
),,( max,
min,
max, sksjsi
),,( max,
min,
min, sksjsi
),,( max,
max,
min, sksjsi
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration• In order to plot these diagrams in a spread sheet, we need to related this
ternary coordinates in a X vs. Y plane as follows:
Ci
Ck
Cj
Y
X
(0.866, 0.50)
(1, 0)
(0, 0)
Ys
Xs
S
Ci,s
siC ,)3
(cos
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
sksjsi
sksisisjsisjs
sksjsi
sisisis
CCCCX
CCY
,.,
,,,,,,
,.,
,,,
5.05.01)
3(cos1
866.0866.0)
3(sin
(75)
• The equations that relate X vs. Y with ternary coordinates are:
(76)
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2.3.3. Property Integration
•The next step is to set up optimization rules as follows:
Relating cost to fractional contribution of sources
Consider two sources s and s+1 that are mixed to satisfy sinks constraints, let xs and xs+1 denote the fraction contribution of sources s and s+1 to the total flow rate of the mixture. Let s be more expensive than s+1, as Costs>Costs+1, therefore we have:
Costmixture = xs (Costs – Costs+1) + Costs+1
From the previous equation we can conclude that in order to minimize the cost of the mixture xs must be minimized
(77)
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2.3.3. Property Integration
Rule No. 1
“When two sources (s and s+1) are mixed to satisfy the property constraints of a sink with source s being more expensive than s+1, minimizing Costmixture is achieved by selecting the minimum feasible value of xs”
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2.3.3. Property Integration
Derivation of relationships between minimum cluster arms (s) and minimum fractional contribution xs
xs cannot be visualized in a ternary diagram, the lever arm on the ternary cluster diagram represents another quantity defined as s, to relate both quantities the AUP is described by equation 62
Source : Component less design of recovery and allocation systems: a functionality based approach
ssNs
sss
AUPxAUP
AUP
AUPx
s1
(78)
(79)
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
Rearranging we have:
Source : Component less design of recovery and allocation systems: a functionality based approach
21
1111
])1([
][])1([
ssss
sssssssss
s
s
AUPAUP
AUPAUPAUPAUPAUPAUP
d
dx
Taking the first derivative:
ssss
sss AUPAUP
AUPx
)1(1
1
(80)
(81)
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2.3.3. Property Integration
Rearranging and simplifying:
Source : Component less design of recovery and allocation systems: a functionality based approach
21
1
])1([ ssss
ss
s
s
AUPAUP
AUPAUP
d
dx
From the previous development rule 2 is obtained:
(82)
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
Rule No. 2
“On a ternary cluster diagram, minimization of the cluster arm of a source corresponds to minimization of the flow contribution of that source; minimum s corresponds to minimum xs”
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2.3.3. Property Integration
Source : Component less design of recovery and allocation systems: a functionality based approach
•Consider the case of fresh external source F, the objective is to minimize its use. A process internal stream W that can be recycled or reused to reduce the use of F. It is desired to mixed them in order to obtain a minimum cost mixture that satisfy sink constraints, the feed to the sink is subject to a number of property constraints that can be mapped in a cluster diagram as follows
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2.3.3. Property Integration
Source : Component less design of recovery and allocation systems: a functionality based approach
Ci
CkCj
W
F
Sink
Optimum F
c
b
a
Minimum distance, this is a necessary condition only. For sufficiency AUP and flow rate must be matched as well
Multiple mixtures
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2.3.3. Property Integration
Source : Component less design of recovery and allocation systems: a functionality based approach
Ci
CkCj
W1
F
SinkF
For multiple sources the line connecting W1 and W2 represents the possible mixtures, the optimal mixing point is the one that gives the minimum s
Multiple mixtures
Multiple sources case:
W2
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2.3.3. Property Integration
Source : Component less design of recovery and allocation systems: a functionality based approach
Ci
CkCj
W
F
Sink
When the process stream W target cannot be met, the stream can be adjusted via an interception device e.g. separation, reaction etc Adjusting properties
will change the cluster value
Adjusting properties
Wintercepted
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2.3.3. Property Integration
Source : Component less design of recovery and allocation systems: a functionality based approach
• For a selected mixing point and a desired s, the fresh arm can be drawn to determine the desired location of the desired location of Wintercepted. Moreover, since the values of AUP are known for F and the mixing point of the sink, one can plug the targeted value of xF into Equation 78 to calculate the desired value of AUP for Wintercepted. Once Wintecepted and AUP are known, we can solve the cluster equations backwards to calculate the raw properties of Wintercepted
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2.3.3. Property Integration
Source : Component less design of recovery and allocation systems: a functionality based approach
• This is the minimum extent of interception to achieve maximum recycle of W or minimum usage of F since the additional interception will still lead to the same target or minimum usage but will result in a mixing point inside the sink and not just on the surrounding of the sink
• Once the task for interception is define, conventional process synthesis techniques can be apply to develop the design and operating parameters for the interception system. The same procedure can be repeated for multiple mixing points resulting in the task identification of the locus for minimum extend to interception
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2.3.3. Property Integration
Source : Component less design of recovery and allocation systems: a functionality based approach
Ci
CkCj
W
F
Sink
Locus for minimum extent of interception
Locus Identification
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
Multiplicity of Optimal values of AUP
A cluster point made of C1sink, C2
sink, C3sink can correspond to multiple combinations
of properties that can give the same cluster values. As a result one can have nMultiple, points within the feasible property domain giving a single cluster value. Three conditions must be satisfied in order to insure feasibility of the sources or mixture of sources going into a sink:
1. The cluster value of the source must be contain within the feasibility region of the sink on the cluster diagram2. The values of AUP for the source and the sink must match3. The flow rate of the source must lie within the acceptable feed flow rate range of the sink
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2.3.3. Property Integration
From Rule No. 1 minimizing xs will minimize CostMixture, therefore we need to select an AUPm (given for the feasible properties p1,m, p2,m, p3,m) that will be minimized by the following relationship between AUPm and xs.
Source : Component less design of recovery and allocation systems: a functionality based approach
1
1
1
1
ssm
s
ss
sms
AUPAUPAUP
x
therefore
AUPAUP
AUPAUPx (83)
(84)
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2. Foundation Elements2.3. Overview of Mass, Energy and Property Integration
2.3.3. Property Integration
To minimize xs and as a result the cost we should select:
Source : Component less design of recovery and allocation systems: a functionality based approach
1
1
max
min
ssmoptimumm
ssmoptimumm
AUPAUPifAUPArgAUP
AUPAUPifAUPArgAUP
If no mixture matches the AUP selected for the sink for the case given by Equation 84 then one has to decrease the value of the sink’s AUP starting with Argmax AUPm till getting the highest value of AUPm within the feasible range of AUP which matches that of the mixture; same procedure is used for Equation 85, by increasing the value of sink’s AUP starting with Argmin AUPm till getting the highest value contained within the feasible range of the sink which matches that of the mixture
(85)
(86)
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2.3.3. Property Integration
Source : Component less design of recovery and allocation systems: a functionality based approach
Currently research is being undertaken to design tools that will cover cases for 1, 2 and more than three properties. This is a very dynamic and changing field of research
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TIER II
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• A tire to fuel processing plant flow sheet is shown in the next slide which is a more complete description for the one given in Example 2. Tire shredding is achieved by using high pressure water jets. The shredded tires are fed to the process while the spent water is filtered. The wet cake collected from the filtration system is forwarded to solid waste handling.
• The filtrate is mixed with 0.20 kg/s of fresh water makeup to compensate for water losses with the wet cake, 0.08 kg water/s and the shredded tires 0.12 kg water/s. The mixture of filtrate and water make up is fed to a high pressure compression station for recycling the shredding unit. Due to the pyrolisis reactions, 0.08kg water is generated
3. Case Study3.1. Tire to Fuel Processing Plant
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• The plant has two primary sources for waste water, the decanter (0.20 kg water/s and the seal pot 0.15 kg/s. The plant has been shipping the waste water for off-site treatment. The cost of wastewater transportation and treatment is $0.02/kg leading to a wastewater treatment cost of approximately $129,000/yr
3. Case Study3.1. Tire to Fuel Processing Plant
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3. Case Study
Filtration
Compression
Water JetShredding
PyrolisisReactor Separation Finishing
Condenser
Decanter
Flare
SealPot
Fresh Water 0.20 kg/s 0 ppmw
Wet Cake to Solid Handling 0.08 kg/s, 0 ppmw
Tires
Shredded Tires
Reactor Off-Gases
Gaseous Fuel
Waste water to treatment 0.20 kg/s
500 ppmw
Fresh water
0.15 kg/s 0 ppmw
Light Oil Flare Gas, 0.15 kg/s
200 ppmw
Waste water to treatment, 0.15 kg/s 0 ppmw
Liquid Fuel
To Atmosphere
Tire to Fuel Plant Flow Sheet
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• The plant wishes to stop off site treatment of wastewater to avoid the cost ($129,000/yr) and alleviate legal liability concerns in case of transportation accident or inadequate treatment of wastewater treatment. For capital budget authorization, the plant has the following economic criteria:
3. Case Study
years 4Savings Annual
investment capital Fixed periodPayback
system site-on
treatmentsite-off
cost operating Annual
- cost avoided Annual Savings Annual
3.1. Tire to Fuel Processing Plant
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Economic Data• Fixed cost of extraction system associated with S2. $ = 130,000
(flow rate of wastewater, kg/s)0.60
• Fixed cost of adsorption system associated with S3, $ = 800,000 (flow rate of wastewater, kg/s)0.72
• Fixed cost of stripping system associated with S4, $ = 280,000 (flow rate of wastewater, kg/s)0.66
• A biotreatment facility that can handle 0.35kg/s waste water has a fixed cost of $260,000 and an annual operating cost of $72,000/yr
Technical Data• Water may be recycle to two sinks: the seal pot and the water-jet
3. Case Study3.1. Tire to Fuel Processing Plant
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Compression station. The following constrains on flow rate and composition of the pollutant (heavy organic) should be satisfied:
Seal Pot• 0.10 Flow rate of feed water (kg/s) 0.20• 0 Pollutant content of feed water (ppmw) 500
Make up to water-jet compression station• 0.18 Flow rate of make up water (kg/s) 0.20• 0 Pollutant content of make up water (ppmw) 50
3. Case Study3.1. Tire to Fuel Processing Plant
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Solution
We will start with an overall mass balance, note that 0.12 kg/s of water are lost in the process and cannot be re used
3. Case Study
Water Generation 0.08kg/s
0.2 kg/s to Compression Station
0.15 kg/s to Seal Pot
0.08 kg/s from Wet Cake
0.15 kg/s from Seal Pot
0.2 kg/s from Decanter
3.1. Tire to Fuel Processing Plant
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Solution
From the overall mass balance we can set the targets for fresh use and wastewater production
3. Case Study
Water Generation 0.08kg/s
0.2 kg/s
0.15 kg/s
0.08 kg/s
0.35 kg/s
No Fresh Water
0.08 kg/s
Wastewater
The source diagram is shown in the next slide
3.1. Tire to Fuel Processing Plant
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Source/Sink Diagram
00.020.040.060.080.1
0.120.140.160.180.2
0.22
0 50 100 150 200 250 300 350 400 450 500 550
ppmw
kg
/s
3. Case Study
Seal Pot
WW from Decanter
Compression Station
WW from Seal Pot
WW from Wet Cake
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• From the source/sink diagram we can see that wastewater from the decanter can be accepted by the seal pot only; the outlet composition of the wastewater coming from the seal pot is 400 ppmw (from the pinch diagram) as shown in Example 2
3. Case Study3.1. Tire to Fuel Processing Plant
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Pinch Diagram
0
50
100
150
200
0 100 200 300 400 500 600
Mass Exchanged 10-6
3. Case Study
Composition from Seal Pot
3.1. Tire to Fuel Processing Plant
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Source/Sink Diagram
00.020.040.060.080.1
0.120.140.160.180.2
0.22
0 50 100 150 200 250 300 350 400 450 500 550
ppmw
kg
/s
Seal Pot
W W from Decanter
Compression Station
W W from Seal Pot
W W from Wet Cake
3. Case Study
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• Wastewater coming from the seal pot cannot be recycled directly to the compression station due to its high pollutant composition, therefore it is required to treat it using an external MSA as shown in Example 2; for this case S4 is the best stripping agent, which will bring down the composition to 50ppmw
3. Case Study3.1. Tire to Fuel Processing Plant
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Source/Sink Diagram
00.020.040.060.080.1
0.120.140.160.180.2
0.22
0 50 100 150 200 250 300 350 400 450 500 550
ppmw
kg
/s
3. Case Study
Seal Pot
WW from Decanter
Compression Station
WW from Stripper
WW from Wet Cake
WW from Seal Pot
3.1. Tire to Fuel Processing Plant
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3. Case Study
Filtration
Compression
Water JetShredding
PyrolisisReactor Separation Finishing
Condenser
Decanter
Flare
SealPot
Wet Cake to Solid Handling
Tires
Shredded Tires
Reactor Off-Gases
Gaseous Fuel
Light Oil
Flare Gas
Liquid Fuel
To Atmosphere
Tire to Fuel Plant Flow Sheet (Revised)
Stripper
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• Now we will proceed to compare the different alternatives in order to make a decision. For the bio-treatment plant we have:
3. Case Study
Annualized Saving Cost = $129,000/yr - $72,000/yr = $57,000/yr
Pay Back = $260,000 / $57,000/yr = 4.56 years
• For the recycling/stripping system:
Annualized Saving Cost = $129,000/yr - $84,270.5/yr = $44,729.5/yr
Pay Back = $96,791.6 / $44,729.5/yr = 2.16 years
Fixed Cost of Stripping = $280,000(0.2)0.66 = $96,791.6
3.1. Tire to Fuel Processing Plant
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• From the results we can conclude that the recycling/stripping alternative is the best economical and technical option. We need to point out that the water contained in the wet cake will not be recovered or treated
3. Case Study3.1. Tire to Fuel Processing Plant
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3. Case Study3.2. Pulp and Paper Process Plant
• Wood chips are chemically cooked in a Kraft digester using a white liquor (mainly NaOH and Na2S). Black liquor (spent white liquor) is converted back to white liquor by a recovery cycle. The digested pulp is then bleached to obtain bleached pulp (fiber I). The plant also buys pulp from another plant (fiber II), the pulp is then sent to two different paper machines (Sink I and Sink II). Paper machine I uses 200 tons/hr of fiber I. A mix of fiber I and II (20 ton/hr and 30 ton/hr, respectively) is fed to paper machine II. Due to interruptions and other disturbances, a certain amount of partly and completely manufactured paper is rejected
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3. Case Study• The rejected fiber is referred as broke, which is passed
through a hydro-pulper and a hydro-sieve resulting in two streams, an underflow which is burnt and an overflow which goes to waste treatment. Part of the broke contains fiber which can be recycle for paper making.
• The properties that are important for the process are:– Objectionable material (OM), undesirable material in the fiber – Reflectivity (R), reflectance of an infinite thick material
compared to a standard– Absorption coefficient (k), measure of absorptivity of light into
the fibers
3.2. Pulp and Paper Process Plant
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3. Case Study
• The mixing rules are:
61
6
2
1
2
1
s
s
s
s
RxR
g
mkx
g
mk
OMxOM
sNs
ssNs
ssNs
3.2. Pulp and Paper Process Plant
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3. Case Study
Kraft Digester
Chemical Recovery
Cycle
Bleaching Paper Machine I
PaperMachine II
Hydro-Pulper
Hydro-Sieve
Fiber II
Fiber I
Reject
Reject
Paper II
Paper I
Underflow
Broke (Overflow)
Pulp
Black Liquor
White Liquor
Wood Chips
OM =0.085
k = 0.0013
R = 0.95
OM =0.0
k = 0.0012
R = 0.85
OM =0.0
k = 0.00065
R = 0.95
20 t/hr
30 t/hr
200 t/hr
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3. Case Study3.2. Pulp and Paper Process Plant
Property Lower Bound Upper BoundOM (mass fraction) 0 0.03
k (m2 / gm) 0.00115 0.00125R 0.85 0.95
Flowrate (ton/hr) 95 100
Property Lower Bound Upper BoundOM (mass fraction) 0 0
k (m2 / gm) 0.0007 0.00125R 0.9 0.95
Flowrate (ton/hr) 45 45
Constraints for Paper Machine I, (Sink I)
Constraints for Paper Machine II, (Sink II)
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3. Case Study3.2. Pulp and Paper Process Plant
Source
OM
(mass
fraction)
k (m2 / gm) R
Maximum Available Flowrate (ton/hr)
Cost
($/ton)Broke 0.085 0.0013 0.95 35 0Fiber I 0 0.0012 0.85 230Fiber II 0 0.00065 0.95 395
Properties of Fiber Sources
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1. Determine the optimal allocation of the three sources, fiber I, II and broke for a direct recycle reuse without new equipment
2. In order to maximize use of process resources and minimize wasteful discharge (broke) how should the designer change the properties of the broke as to achieve maximum recycle?
3. Case Study3.2. Pulp and Paper Process Plant
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SolutionIn order to translate the data from property domain to cluster domain we will select arbitrarily reference values as:
3. Case Study3.2. Pulp and Paper Process Plant
0.1
/001.0
02.02
R
gmmk
OMref
ref
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We will proceed to calculate the cluster values for the sources as follows:
3. Case Study3.2. Pulp and Paper Process Plant
38.173.065.00
577.1377.02.10
28.673.03.125.4
II
I
RkOMFiber
RkOMFiber
RkOMBroke
AUP
AUP
AUP
Source OM
k
R
Broke 0.085/0.02 0.0013/0.001 0.956/16
Fiber I 0 0.0012/0.001 0.856/16
Fiber II 0 0.00065/0.001 0.956/16
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3. Case Study3.2. Pulp and Paper Process Plant
12.028.6
735.0
21.028.6
3.1
677.028.6
25.4
,
,
,
BrokeR
Brokek
BrokeOM
C
C
C
Similarly for Fiber I and II we obtain:
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3. Case Study3.2. Pulp and Paper Process Plant
239.0577.1
377.0
761.0577.1
2.1
0577.1
0
,
,
,
IFiberR
IFiberk
IFiberOM
C
C
C
533.038.1
735.0
471.038.1
65.0
038.1
0
,
,
,
IIFiberR
IIFiberk
IIFiberOM
C
C
C
Now we can proceed to transform the ternary points to X vs. Y plot
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3. Case Study3.2. Pulp and Paper Process Plant
452.05.01
586.0866.0
,,
,
BrokeOMBrokekBroke
BrokeOMBroke
CCX
CY
239.05.01
0866.0
I ,I ,I
I ,I
FiberOMFiberkFiber
FiberOMFiber
CCX
CY
530.05.01
0866.0
II ,II ,II
II ,II
FiberOMFiberkFiber
FiberOMFiber
CCX
CY
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Ternary / X-Y Diagram
0
0.2
0.4
0.6
0.8
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
X
Y
Broke
Fiber I Fiber II
COM
Ck
CR
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• Now we need to proceed to locate sinks in the diagram by using the point illustrated in slide 187
3. Case Study3.2. Pulp and Paper Process Plant
),,(),,(
),,(),,(
),,(),,(
minmaxminminmaxmin
minmaxmaxminmaxmax
minminmaxminminmax
,I ,I ,,,,
,I ,I ,,,,
,I ,I ,,,,
ISinkRSinkkSinkOMsksjsi
ISinkRSinkkSinkOMsksjsi
ISinkRSinkkSinkOMsksjsi
For Sink I:
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3. Case Study3.2. Pulp and Paper Process Plant
229.0677.1/377.0
681.0677.1/15.1
09.0677.1/15.0
677.1
377.00.1/85.0
15.1001.0/00115.0
15.02.0/03.0
max ,
min ,
max ,
66min
min
max
,
I ,
I ,
ISinkOM
ISinkk
ISinkOM
C
C
C
AUPISinkR
Sinkk
SinkOM
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3. Case Study3.2. Pulp and Paper Process Plant
213.0777.1/377.0
703.0777.1/25.1
084.0777.1/15.0
777.1
377.00.1/85.0
25.1001.0/00125.0
15.02.0/03.0
max ,
min ,
max ,
66min
max
max
,
I ,
I ,
ISinkOM
ISinkk
ISinkOM
C
C
C
AUPISinkR
Sinkk
SinkOM
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3. Case Study3.2. Pulp and Paper Process Plant
23.0627.1/377.0
77.0627.1/25.1
0627.1/0
627.1
377.00.1/85.0
25.1001.0/00125.0
02.0/0
max ,
min ,
max ,
66min
max
min
,
I ,
I ,
ISinkOM
ISinkk
ISinkOM
C
C
C
AUPISinkR
Sinkk
SinkOM
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3. Case Study3.2. Pulp and Paper Process Plant
),,(),,(
),,(),,(
),,(),,(
maxmaxminmaxmaxmin
maxminminmaxminmin
maxminmaxmaxminmax
,I ,I ,,,,
,I ,I ,,,,
,I ,I ,,,,
ISinkRSinkkSinkOMsksjsi
ISinkRSinkkSinkOMsksjsi
ISinkRSinkkSinkOMsksjsi
For Sink I, continuation:
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3. Case Study3.2. Pulp and Paper Process Plant
361.0035.2/735.0
565.0035.2/15.1
074.0035.2/15.0
035.2
735.01/95.0
15.1001.0/00115.0
15.02.0/03.0
max ,
min ,
max ,
66max
min
max
,
I ,
I ,
ISinkR
ISinkk
ISinkOM
C
C
C
AUPISinkR
Sinkk
SinkOM
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3. Case Study3.2. Pulp and Paper Process Plant
39.0886.1/736.0
61.0886.1/15.1
0886.1/0
886.1
736.01/95.0
15.1001.0/00115.0
02.0/0
min ,
min ,
min ,
66max
min
min
,
I ,
I ,
ISinkR
ISinkk
ISinkOM
C
C
C
AUPISinkR
Sinkk
SinkOM
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3. Case Study3.2. Pulp and Paper Process Plant
37.0986.1/736.0
63.0986.1/25.1
0986.1/0
986.1
736.01/95.0
25.1001.0/00125.0
02.0/0
min ,
min ,
min ,
66max
max
min
,
I ,
I ,
ISinkR
ISinkk
ISinkOM
C
C
C
AUPISinkR
Sinkk
SinkOM
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Sink I and Sources
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
X
Y
Broke
Fiber I
Fiber II
COM
CRCk
COM Ck Xsink I Ysink I
0 01 0
0.5 0.8660.677 0.210 0.452 0.5860.000 0.761 0.239 0.0000.000 0.471 0.529 0.0000.090 0.681 0.274 0.0780.084 0.703 0.255 0.0730.000 0.770 0.230 0.0000.074 0.565 0.398 0.0640.000 0.610 0.390 0.0000.000 0.630 0.370 0.000
Sink I
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• Similarly for Sink II we have:
3. Case Study3.2. Pulp and Paper Process Plant
Sink II Low High RefOM 0 0 0.02k 0.0007 0.001 0.001R 0.9 0.95 1F 45 45
COM Ck Xsink I Ysink I
0 01 0
0.5 0.8660.677 0.210 0.452 0.5860.000 0.761 0.239 0.0000.000 0.471 0.529 0.0000.090 0.681 0.274 0.0780.084 0.703 0.255 0.0730.000 0.770 0.230 0.0000.074 0.565 0.398 0.0640.000 0.610 0.390 0.0000.000 0.630 0.370 0.0000.000 0.568 0.432 0.0000.000 0.702 0.298 0.0000.000 0.702 0.298 0.0000.000 0.488 0.512 0.0000.000 0.488 0.512 0.0000.000 0.630 0.370 0.000
OM
Min OM
Max k
Min k
Max R
Min R
Max
0 0 0.7 1.25 0.531441 0.735092
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Sink I - II and Sources
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
X
Y
Broke
Fiber I Fiber II
Sink II
COM
CRCk
Sink I
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Now we proceed to identify the minimum distance for Sink I, that will minimize the use of fresh sources
3.2. Pulp and Paper Process Plant
Sink I and Sources
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
X
Y
Broke
Fiber I
Fiber II
COM
CRCk
Sink I
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Sink I - II and Sources
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
X
Y
(0.27, 0.85)
COM
CkCR
In order to get the length of the arm to obtain s one can measure it from the graph or:
221
221 )()( yyxxd
or
By Equation 65
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The distance between mixture and broke is:
3. Case Study3.2. Pulp and Paper Process Plant
533.0
)586.0085.0()452.027.0(
)()(
22
221
221
d
d
yyxxd
The Total distance is:
623.0
)0586.0()239.0452.0( 22
d
d
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Therefore s is:
3. Case Study3.2. Pulp and Paper Process Plant
855.0623.0
533.0 IFiber
Using Equation 65:
855.0677.00
677.0098.0
, ,
,
, ,
BrokeOMIFiberOM
BrokeOMMixtureOM
IFiber
IFiberOMIFiberBrokeOMBrokeMixtureOM
CC
CC
CCC
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From Equation 86, AUPmoptimum = 2.035
3. Case Study3.2. Pulp and Paper Process Plant
103.1577.1
035.2855.0 IFiberX
855.0677.00
677.0098.0
, ,
,
, ,
BrokeOMIFiberOM
BrokeOMMixtureOM
IFiber
IFiberOMIFiberBrokeOMBrokeMixtureOM
CC
CC
CCC
Therefore xs is:
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TIER III
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4. Open Ended ProblemAn ethylene/ethyl benzene plant is shown in the next flow sheet. Gas oil is being cracked with steam in a pyrolysis furnace to form ethylene, low BTU gases, hexane, heptanes, and heavier hydrocarbons. The ethylene is then reacted with benzene to form ethyl benzene. Two waste water streams are formed one of the streams is the quench water recycle for the cooling tower and the second one is the waste water from the ethyl benzene portion of the plant. The primary pollutant present in the two waste water streams in benzene. Benzene must be removed from the waste water that will be use to quench the cooling tower, coming from the settling unit to a concentration of 180ppm before it can be recycled back to the cooling tower and the boiler water treatment process. Benzene must also be removed from the waste water stream coming from the lower separation unit down to a composition of 380ppm before the waste water stream can be sent to biotreatment
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PyrolysisFurnace
BoilerWater
Treatment
Cooling Tower
Settling
UpperSeparation
Ethyl benzeneReactor
Lower Separation
Gas Oil
Steam
FreshWater
Refuse
Waste water 150kg/s 1100ppm
FreshWater
Benzene
Waste water 70kg/s 2100ppm
Vent Fuel
Recycle Quenched Water
To Biotreatment
Low BTU gasesHexane 0.8kg/s 10ppmw
Heptane 0.4kg/s 17ppmw
Heavy Hydrocarbons
Ethylbenzene
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4. Open Ended ProblemThe heptane and hexane streams will be used to recover part of the benzene, the desired final composition of them is unknown and has to be determined by the engineer, after which they are sent to finishing and storage. The mass transfer driving forces 1 and 2, should be at least 25,000 and 29,000ppmw respectively. The equilibrium data for benzene transfer from waste water to hexane (1) and heptane (2) are:
y = 0.012x1
y = 0.009x2
Where y, x1 and x2 are in mass fractions. Two external MSA are being considered for removing of benzene; air and activated carbon. Air is compressed to 2 atmospheres before stripping. Following stripping, benzene is separated from air using condensation.
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4. Open Ended Problem• Henry’s law can be used to predict equilibrium for the
stripping process. Activated carbon is regenerated using steam in a ratio of 2kg steam : 1 kg of benzene adsorbed on activated carbon. Make up at a rate of 1.2% of recirculating activated carbon is needed to compensate for losses due to regeneration and deactivation. Over the operating range, the equilibrium relation for the transfer of benzene from waste water onto activated carbon can be described by:
y = 6.8x10-4x4
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4. Open Ended Problem1. Label the rich and lean streams2. Construct a pinch diagram, identify pinch location,
minimum load of benzene to be removed by external and excess capacity of MSA’s Consider the four MSA’s to choose from and find the MOC needed to remove benzene. Use the cost data found in slide 97
3. Apply the algebraic approach4. Design the network for the plant and draw a modified
flow sheet5. Comment on your results, what limitations do you think
have the methods used in the calculations if any, what conclusions can you draw based on your results?
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I wish to thank for their cooperation and guidance:
• Dr. Mahmoud M. El-Halwagi Professor Texas A&M• Dr. Jules Thibault Professor University of Ottawa• Dr John T. Baldwin Professor Texas A&M• Dr. Dustin and Georgina Harrel Texas A&M• Vasiliki Kazantzi PhD student Texas A&M• Qin Xiaoyun Researcher Candidate Texas A&M• Daniel Grooms PhD student Texas A&M
William Acevedo, April 2004
5. Acknowledgments
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• El-Halwagi M. Mahmoud, Pollution Prevention through Process Integration Systematic Design Tool, Academic Press, 1997
• El-Halwagi M. Mahmoud, Glasgow M. Ian, Eden R. Mario, Qin Xiaoyun, Property Integration: Componentless Design Techniques and Visualization Tools, Texas A&M
• Kazantzi V., Harell D., Gabriel F., Qin X., El-Halwagi M.M., Property Based Integration For Sustainable Design, AIChE Annual Meeting, 2003
• Seider D. Warren, Seader J.D., Lewin Daniel R., Product and Process Design Principles, Wiley International, 2004, 2d ed
• Shelley, M.D. and El-Halwagi M.M., Component-less Design of Recovery and Allocation Systems: A Functionality based Clustering Approach, Computers and Chemical Engineering, 24, 2081-2091, 2000
• Qin X., Gabriel F., Harell D., El-Halwagi M.M., Algebraic Techniques for Property Integration Via Componentless Design, Texas A&M
References