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Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 20081
Bioethanol Meeting, Detmold, 2008
Ethanol Plant Revampand
Process Optimization by proven
Membrane Technology
Capacity Increase and Reduction of Energy Consumption
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 20082
Content
• Ethanol separation• Rectification design and operation• Energy saving at rectification• Example:
Stand alone membrane dehydration system• Recycling permeate/regenerate to distillation• Integrated dehydration Systems• Example:
Cascade system• Project work sequence • Membrane selection
Membrane qualitiesMembrane modules
• Examples: Process optimisation/redesign
• Conclusion• Outlook
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 20083
95908580756050403010 7020 1000
95
90
85
80
Ethanol in liquid (wt%)
75
70
60
50
40302010
Etha
nol i
n Va
pour
(wt%
)
Azeotrope (95.6 wt%)
0
100
Fermentation
Distillation
Dehydration
Possible Working range forMembranes
Working range for
Line of equalliquid/vapourconcentration
Alcohol-Water Vapour equilibrium curve
Traditional dehydrationtechnology
Ethanol Separation
80 w% Ethanol is proven working range for membranes
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 20084
Rectification Design and Operation
No. of theoretical Stages
8 1612
1.0
2.0
3.0
0
4.0
4 20 24 28
15 wt.%8 wt.%5 wt.%
Water content in head product
Possible energy saving
Reb
oile
rEne
rgy
Energy consumption at rectification
5w% water vs 15w% water at column top
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 20085
Feed:
55 w% Ethanol
99,5 w% Water
80 w% Ethanol
46%
44%
Energy Saving at Rectification
80 w% vs 93 w% Ethanol at top
93 w% Ethanol
Column theor. trays: 20 30
Heating energy: 240 528
Cooling energy: -226 -512
Existing rectification:
double capacity and produce 99,7w% Ethanol instead of 93w% Ethanol at same energy consumption
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 20086
Reduction of Operating Costs:High Water Content to Dehydration
Use the advantage of high water content feed by use of Membranes
Case A:Stand alone dehydration systems
independent from raw Ethanol production
Case B:Integrated dehydration systems
connect to the vapour outlet of rectification/distillation
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 20087
Stand Alone Membrane Dehydration System
Liquid Feed
Ethanol 99,7w% Water 99,9%
Raw Ethanol
Feed: 85w% Ethanol, liquidincluding recycle treatment
App. 0,72 kg steam / kg dehydrated Ethanol
Vapour compressionincluding recycle treatment
App. 0,44 kg steam / kg dehydrated ethanol
Compared to molecular sieve (top at 93w% Ethanol)
70 % saving heating energy at regenerate recycle
Revamp existing systems with membranes:-increase capacity-save heating energy-save cooling water consumption
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 20088
Membrane
Molecular Sieve
Recycling of Regenerate/Permeate
Molecular Sieve - Membrane
Regenerate/permeate:Molecular sieve:
Flow: 52 % of Ethanol output, 19 w% Water, Qrec.=0,45 kW/kg ETOH
Membrane:
Flow: 46 % of Ethanol output, 67 w% WaterQrec.=0,13 kW/kg ETOH
31%
Regenerate
recycle energy
Ethanol 99,7w%
93 w% Ethanol
Rec
tifie
r Regenerate
Ethanol 99,7w%
Rec
tifie
r
80 w%Ethanol
Regenerate
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 20089
Integrated Dehydration Systems
Complex Heat Integration in Complete Ethanol Plants
•Rectification is not isolated
•Heat is exchanged within theoverall plant
•Big variety of process designs
•Process redesign needed, e.g. pressure cascadee.g. vapour compressione.g. different heat integratione.g. modifying split rates at columns
•Membranes must fit to the pressure temperature conditions Others
Fermentation
Distillation
DryingRectification
Dehydration
Steam input
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 200810
Integrated Dehydration UnitsExample: Heat integration by cascade systems
Cascade reuse of energy:
-pressure cascade up to 7 bar
Associated temperatures at 80/20w%
-Saturation = 140 °C
-plus 15°C superheat => 155 °C
-plus safety margin => 170 °C
Rec
tifie
r
Stri
pper
Traditional Dehydration
Stri
pper
1Membrane-Dehydration
Stri
pper
2
Rec
tifie
r
Original process
Membrane process (only1 alternative shown)
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 200811
Upgrading Existing Ethanol Processes / Plants
Adopt
process design
Redesign
heat integration concept
Select Proper
Membranes
Check process design
Improved economy
Each plant is different specific considerations needed
-Low-, middle-, high pressure
Higher value product
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 200812
Membrane SelectionDifferent membranes and modules
Flat membranes
Module type: „Sandwich“
Zeolite membranes
Module type:
„Shell & tube“
Capillary membranes
Module type: „Cartridge“
Courtesy Sulzer, Mitsui, WFX
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 200813
Membrane SelectionQualities of different membranes
Flat Membranes Ceramic Membranes
Max. temperature
Typical op. Pressure
Chemical stability
Permeate vacuum
Cooling water
Cold water
Permeat solvent cont.
Sealings
Maintenance
Vacuum vessel
Capacity reserve:-Feed pressure-Sweep-Vacuum
Cost
Operation mode
App. 95-110°C
App. 1 barg
medium
>10 mbar abs
at stage 1
at stage 2
App. 15%
App. 4m per 1m²
difficult
needed
Capacity reserve:-no-difficult, inefficient-no
Low
VP + PV
App. 180°C
App. 5 barg
medium
>10 mbar abs
At stage 1
At stage 2
App. 10%
2 O-rings per tube (0,8 m²)
fair
-
Capacity reserve:-yes-no-no
Medium
VP + PV
App. 180°C
App. 5 barg
medium
>100 mbar abs
Yes, needs only 1 stage
-
App. 40%
2 rings per 130 m²
easy
-
Capacity reserve:-yes-yes-yes
high
VP
Conclusion: Select Membranes with regards to the overall circumstances
Capillary Membranes
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 200814
Membrane SelectionOperational availability and maintenance
Flat Membranes Ceramic Membranes Capillary Membranes
Courtesy Sulzer, Mitsui, WFX
Accessibility
Operational availability
Easy access - ++ ++
Easy fault detection - - + ++
Easy replacement - - + ++
Continue production if faulty - - ++
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 200815
Membrane Requirements
Mechanical and chemical qualities:• Mechanical strength up to 10 bar (depending on process)
• Temperature up to 180°C (depending on process)
• Tolerant to high water content (min 20w% water)• Tolerant to fusel oil• Solvent resistance (alcohols, heads: e.g.: acetate, cetone, toluene, organic acids, etc)• Chemical resistance app. pH 2-13
Operation, availability, maintenance:• Static operation, no cycling, no moving parts• Easy fault identification • Easy maintenance • Replacement without plant shut down• Continued production at lower capacity in case of failure• Normal cooling water required
Commercial:• Long warranty period on capacity and product quality• Purchase or leasing
All proven in industrial scale, but….
proper membranes must be selected
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 200816
Original design with molecular sieve: 2,34 kg steam / kg ethanol 99,7w%
New design with membrane dehydration: 1,48 kg steam / kg ethanol 99,7w%
Saving 27% heating energy and NO additional equipment
reduction cooling water consumption
Optimization Cascade Process with Membranes
-Replace molecular sieve by membranes
-Rectification stops at 80w% ethanol
-Redesign heat integration
Stri
pper
1
Stri
pper
2
Rec
tifie
r
Hea
ds
Membrane
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 200817
Conclusion
Membranes, properly selected, proved in industrial application:
•Reliable, long term operation
•Chemical resistance against byproducts/solvents
•Various raw material possible
•Easy to operate
•Simple to maintain
•Big potential for saving in heating energysaving cooling water consumptionreduce emissions
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 200818
Stand alone dehydration systems:
Revamp with membranes for dehydrationIncrease capacity and reduce energy consumption
Existing raw ethanol plants:Upgrade existing equipment with membrane dehydration and produce higher value product i.e. Ethanol 99,7-99,95w% Ethanol combined with less energy consumption
New ethanol process designs:
Integrated membrane dehydration will reduce energy consumption significantlyConsider membranes at an early stage in process design and selection
Conclusion
Redesign and revamp of existing systems and processes
Low-, middle-, and high pressure processes
Debottle Necking:
Membranes can set free capacity for distillation / rectification / condensation,throughput
Buss-SMS-Canzler GmbH Bioethanol Meeting, Detmold / B. Kaiser / April 200819
Outlook
Membrane feed with 50 w% water is under investigation of long term pilot testingEnergy saving will be increased even more
Producers and Engineering Companies are welcome
Visitors to reference plants are welcome