DIP_simu_04.ppt p. 1 Integrated Process Design (Simulation) Rigorous definition: Basic Specification Forms Components. Electrolytes Reliable design of

DIP_simu_04.ppt p. 1

Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

Rigorous definition: Basic Specification Forms

• Components. Electrolytes

• Reliable design of new components. • Kinetic CSTR reactors.

DIP_simu_04.ppt


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

Components: Electrolytes

• Template: General with metric units.• Process flow diagram• Setup:

•Title: Absorption of SH2• Specify ‘molar flows’ and ‘mole fractions’ in the stream table.

200 m3/h70ºC, 1 barAIR + 2%MOL SH2

300 kg/h30ºC, 1bar10%W NA2CO3

10 stages

EXAMPLE: Absorption of a stream, mixture of air and SH2, in an aqueous Na2CO3 solution. Check if the concentration of SH2 in the exit stream goes bellow 50 ppm.


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

EXAMPLE: Components:

• DefinE: N2, O2, SH2, AGUA, NA2CO3 (AIR can not be defined as such because N2 and O2 have different Henry constants)

• [Elec Wizard]• Include salt formation: OFF• Include water dissociation: ON• True component approach• Review Henry components: N2, O2, SH2, CO2.


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

• [Review generated Henry-comps list]: check the content of the GLOBAL group creado in/Componentes/Henry comps• Check:

• /Properties/Specifications• Properties/ Parameters/ Binary interaction/ HENRY-1 , NRTL-1, VLCLK-1• Properties/ Parameters/ Electrolyte Pair/ GMELCC-1, GMELCD-1, GMELCE-1, GMELCN-1


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

• Stream 1: 200 m3/h, 70ºC, 1 bar,

AIRE + 2%MOL SH2 Air: O2=0.98*0.21=0.206,

N2=0.98*0.79=0.774• Stream 3:

300 kg/h, 30ºC, 1bar,10%W NA2CO3

• D-110: Configuration: 10 stagesRun

Results Available with errors

DIP_04a.apw


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

EXAMPLE: DIP_04b.apw• /D-110/ Setup: Configuration: Convergence=Custom (in order to allow change the algorithm).• /D-110/ Convergence: Basic: Algorithm=Sum-Rates• Run

DIP_04b.apw

• Errors are caused by a wrong choice of the convergence algotithm (default).

• Ask for help for absorbers


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

Try the alternative suggested solution:• /D-110/ Setup: Configuration: Convergence: Standard• /D-110/ Convergence: Advanced: Absorber=Yes

/Run /Reinitialize [OK] [Aceptar] /Run /Start )

DIP_04c.apw


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

Initial estimates:• /D-110/Estimates: Temperature

DIP_04d.apw

Run


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

10 ppm de SH2/Blocks/D-110/Profiles: Compositions


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

Design a plant to produce 10.000 Tm/year of monochlorobenzene (MCB). Maximum allowed production of polychlorinated products is 1.000 t/yr.

Literature: Ullmann and Kirk-Othmer encyclopaedias.

• The reaction takes place in a stirred tank with liquid benzene and Cl2 gas. Low temperatures are used (20 - 80ºC).

Benzene chlorination


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

BEN

MCB

ODCB PDCB

123TCB 124TCB

1(82)

2(4.16)

3(3.89)

4(1.0) 5

(0.275)6

(0.32)


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

New component definition• A non-databank component is defined (123TCB is assumed to be a non-databank

component) by the conventional procedure (not the Wizard). The reliability of the estimated values will be verified later.

• Available data of 123TCB: MW = 181.45, Tb = 218.5

• Define all components: HCL, CL2, BEN, MCB, PDCB, ODCB, 124TCB y 123 TCB.• /Setup /Specifications: Run Type = Property Estimation• /Properties /Estimation /Input /Setup: Estimate all missing parameters.• /Properties /Molecular Structure: 123TCB .................. Define.• /Properties /Parameters /Pure Component: New , Scalar: MW = 181.45, Tb = 218.5 • Run

DIP_MCB_a.apw/Properties /Molecular Structure: General /Properties/Parameters/Pure components/PURE-1: Input


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

Results may be displayed in /Properties /Estimation /Results, or in /Properties /Parameters /Pure components

/Properties /Estimation /Results: 123TCB /Properties /Parameters /Pure component /PCES-1

• NOTE: After estimation parameters are saved in the databank of the project file. The estimation form may be then disabled. The ‘Reinitialize’ command will no delete these values saved in the databank.


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

Verification• Can we trust these estimates? The suitability of the methods used by Aspen Plus must be

verified. Estimation methods are used for a databank component with similar molecular structure: 124TCB.

• Two parameters are used to show the procedure: • Critical temperature (TC).• Standard enthalpy of formation for ideal gas (DHFORM).

• Estimate TC y DHFORM by all available methods for 124TCB.

• Compare with values in Aspen databank.

DIP_MCB_b.apw

/Properties /Estimation /Compare: Setup

/Properties /Estimation /Input: Setup

/Properties /Estimation /Input: Pure Component: TC

/Properties /Estimation /Input: Pure Component: DHFORM


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

• Many errors are reported:• TC may not be estimated by MANI method becuse of missing parameters: Remove.• Molecular structure is required: Supply.• Run

DIP_MCB_c.apw/Properties /Estimation /Results: Pure Component: 124TCB /Properties /Estimation /Compare Results: Pure Comp: 124TCB

• While TC is correctly predicted by any method, DHFORM is always wrong, especially when the default method is used.

• To continue the simulation disable the estimate input form and change the Run Type to Flowsheet mode.


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

Reactor design

• Choice of the reactor:

• Considering reactions (mixed in series for MCB and in parallel for CL2) the choice of reactor may be elucidated:

Concentration of interest Performance Flow patternBEN REACTANT HIGH Conversion PFRCL2 REACTANT LOW Selectivity CSTRMCB PRODUCT LOW Selectivity PFR

• A gas-liquid stirred tank reactor will be used for the reaction. Therefore several CSTR in series will be used, where BEN will flow in series, while CL2 will be fed in parallel to all reactors.

• A low proportion of CL2 will also lead to higher selectivity. Furthermore, CL2 should react completely to avoid its mixture with hydrogen chloride at the outlet gas stream.


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

• /Properties /Estimation /Input: Setup: Do not estimate any parameters• /Setup/Specifications: Global: Runtype=Flowsheet• /Properties /Specifications: Global: Base Method=NRTL • /Properties /Specifications: Global: Henry components: <New> HC-1 [OK]• /Components /Henry components /HC-1: HCL, CL2• /Properties /Parameters /Binary Interaction /NRTL-1: Input: Estimate all missing parameters by UNIFAC• Process flow diagram:

• Stream 1: 20ºC, 1 bar, 100 kmol/h BEN• Stream 2: 20ºC, 1 bar, 200 kmol/h CL2 (use now CL2 in excess, to avoid errors, since kinetics are CL2 independent. A more realistic flow will be entered later).

• CSTR: 0 bar, 20ºC (lower temperatures increase selectivity: Ea1<Ea2), Vapour-Liquid, Residence Time, 5 hours.

• Reactions: define in /Reactions/Reactions: [New] (R-1, POWERLAW).


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

Kinetics• All reactions show first-order kinetics with respect to the aromatic reactive and zero-

order with respect to CL2 (liquid phase is saturated of CL2).

• Parameters are available in literature for the two main reactions (1 and 2). For the other polychlorination reactions the same Ea that in reaction 2 will be assumed. The exponential factor will be calculated from K conversion factors reported in Kirk-Othmer encyclopaedia.

aE

RTi i aromático ir k c k Ae,

Reacción k (s-1) Ea (J/kmol)1 8.800E+07 7.500E+072 1.000E+08 8.300E+073 1.430E+08 8.300E+074 2.420E+07 8.300E+075 6.670E+06 8.300E+076 7.744E+06 8.300E+07

BEN

MCB

ODCB PDCB

123TCB 124TCB

1(82)

2(4.16)

3(3.89)

4(1.0) 5

(0.275)6

(0.32)


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

/Blocks/R-130 /Setup: Specifications REACTIONS: /Reactions/Reactions: [New], R-1, Powerlaw

/Reactions/Reactions/R-1: Kinetic

Fill out the form for the 6 reactions

DIP_MCB_d.apw


Inte

gra

ted

Pro

cess

Des

ign

(S

imu

lati

on

)

/Data /Results Summary /Streams

RUN

R-310: Results

Documents

DIP_simu_04.ppt p. 1 Integrated Process Design (Simulation) Rigorous definition: Basic Specification Forms Components. Electrolytes Reliable design of