Converting Red Liquor, Pulp, and Sludge to Ethanol

Spring 2009 Design Class

Paper Science & Engineering 487

College of Forest Resource

University of Washington11 June 2009

Agenda

Background Red Liquor to Ethanol Production

Process Overview Process Detail Mill Integration Process Economics Environmental and Safety Conclusions and Recommendations

Pulp to Ethanol Production Sludge to Ethanol Production Process Comparison Conclusion

Background

Ethanol – Production Benefits:

Environmental Economical Efficient

Project Objective: Integrate the production of ethanol into the KC Everett mill. Group Objectives:

Production of ethanol from Red Liquor, Pulp, and Sludge

http://i.treehugger.com/files/ch3ch2oh.jpg

Fermentation Options

Three Fermentation MicroorganismsEscherichia coli

Genetically engineered strain KO11 Yield 0.44 g ethanol /g sugar Metabolize 5 and 6 carbon sugars

Zymomonas mobilisGenetically Engineered Strain ZM4:ZB5 More tolerant of acetic acid Yield 0.47g ethanol/g sugar Metabolize 5 and 6 carbon sugars

Saccharomyces cerevisiaStrain 424A(LNH-ST) Yield 0.41 g ethanol/g sugar Metabolize only 6C sugars Proven performance with red liquor

Red Liquor to Ethanol

Chris Ardales, Colynn Boyd,

Sabrina Burkhardt, Danielle Greenwood

Paper Science & Engineering 487

College of Forest Resource

University of Washington

Process Overview

Assumptions Neglect Inhibitors 86% Fermentable Hexoses converted 77% Fermentable Pentoses converted Mill is capable of handling increased steam production

Critical Unit Operations Raise pH with Ammonium Hydroxide prior to fermenting Lower Temperature prior to fermenting Use of Zymomonas mobilis as fermenting agent

Nutrients: corn steep, diammonium phosphate SSL taken from 5th MEE, remaining liquor returns to 1st MEE

Flow Diagram Follows:

Evaporator 5th Stage

Stream 1•Red Liquor•504 GPM•Temp = 149F•pH = 2.6

1

Heat ExchangerTin= 149FTout=106F

Fermenter•5 batch tanks

•1250000 gallon total capacity•pH 5.75 for 1st 24 hrs•pH 6.0 for last 6 hrs•0.47g etOH/g sugar

2Stream 2•504 GPM•Temp = 106F•pH = 2.6

To 1st Stage

3

4

5

Stream 3•NH4OH for pH adjustment•Temp = 106F

Stream 4•NH4OH for pH adjustment•Temp = 106F

Stream 5•Nutrient Addition•Temp = 106F•Corn steep liquor•Diammonium phosphate

6Stream 6•Fermenting Inoculum•Temp = 106F•Z. mobilis

7Stream 7• to storage tanks

CO2 and VOC vent

Evaporator 1st Stage

Stream 8•Water and solids from beer column•504 GPM•Temp = 149F•pH = 2.6

8

RectifierTemp = 212F

Beer Column•Temp = 212F

10

7

Stream 7 (from storage tanks)•Ethanol 15 gpm•Water 418 gpm•Dissolved solids 75 gpm•Temp = 106F9

Stream 9• ethanol 15 gpm, 92.5% •Water 1 gpm, 7.5%

Molecular SieveTemp = 212F

CO2 and VOC vent

Stream 10• ethanol 15 gpm, 95% •Water <1 gpm, 5%

Stream 11• ethanol 15 gpm, 99.5% •Water <0.1 gpm, 0.5%

12

13

11

From evaporator 5th stage

Stream 12•Water to sewer

Stream 13•Water to sewer

Process Detail - WinGEMS

Process Detail - WinGEMS

Process Detail - WinGEMS

Process Detail – Inputs to Process

SSL SW HW

Total Mass Flowrate (klb/hr) 239.59 239.59

Total Dissolved Solids (klb/hr) 56.06 56.06

Total Sugars (klb/hr) 14.63 13.25Fermentable 6 C Sugars (klb/hr) 12.32 9.32Fermentable 5 C Sugars (klb/hr) 1.86 3.59

Other Solids (klb/hr) 4.40 8.94

Lignin Mass Flowrate (klb/hr) 36.59 33.13

Water (klb/hr) 183.53 183.53

Temperature (deg F) 149 149

pH 2.6 2.6

Process Design

Fermenter Outflow to Beer Column

Softwood Hardwood

Ethanol concentration (%) 2.3 2.0

Ethanol (gpm) 14.5 12.6

Total solids (kpph) 40.9 42.1

Water (gpm) 404 413

Process Design

Softwood Hardwood

Dissolved Solids (%) 18.4 19.0

Lignin and extractives (kpph)

35.7 32.3

Sugars (kpph) 0.44 0.33

Water (kpph) 234 234

Beer column outflow to evaporator stage 1

Beer column flow to rectifier and sieve

Process Design

Softwood Hardwood

Ethanol concentration (%) 93.0% 93.0%

Ethanol (gpm) 14.5 12.6

Water (gpm) 195 170

Softwood Hardwood

Ethanol concentration (%) 99.8% 99.8%

Ethanol (gpm) 14.5 12.6

Ethanol (MM gal/yr) 7.3 6.4

Water (gpm) 0.004 0.004

Outflow from rectifier and sieve

Process Detail – Results from WinGEMS

Ethanol Production (WinGEMS Simulation)

Softwood Hardwood

Ethanol (MM gal/yr) 7.6 6.8

Ethanol Production (calculated)

Softwood Hardwood

Ethanol (MM gal/yr) 7.3 6.4

Steam Production from Red Liquor

Without Fermentation

After Fermentation

Wingems Simulation

268 KPPH 127 - 185 KPPH 197 KPPH

31%-53% reduction in steam from red liquorDistillation requires 33 KPPHOther fuels must be burned to makeup the steam requirement Wingems simulation is optimistic

Process Design

Without Fermentation After Fermentation

35.3 28.3

Change in power production from WINGEMS

Process Economics

Capital Costs

Fermentation $ 2,600,000

Distillation $ 5,900,000

Storage $ 800,000

Utilities $ 200,000

Total Installed Equipment Cost $ 9,500,000

Added Costs $ 7,000,000

Total Project Investment $ 16,500,000

Estimated based on NREL corn ethanol process Exclude non-applicable operations 2008$ using ppi Installation factors, cost relationships used by NREL Scaled based on production level

Process Economics

Operating Costs (cents/gal ethanol)

Variable Operating Costs

Chemicals 2.0

Fermentation Nutrients 1.4

Steam 49.5

Fixed Operating Costs 16.9

Total 69.8

Equivalent annual worth values 20 year projection, 20% rate of return

Estimated based on NREL corn ethanol process Chemicals vary from NREL process Fixed costs based on production as in NREL

Process Economics

Steam Use (klb/hr)

Process Demand 33

Steam Production from SSL loss 112

Total 145

Value at $2.2/gal ($/yr) $ (2,800,000)

Cost of Natural Gas Replacement ($/yr) $ (3,400,000)

Natural gas cost: $4/MM Btu

Profitability

20 year projection (pre-tax) Ethanol selling price of $1.50/gal Ethanol production of 7.1 MM gal/yr Desired rate of return at 20%

Net Present Value = $17.3 MM

Break Even Ethanol Price: $1.06/gal

Environmental and Safety

Displacement of Carbon released from gasoline

Calculated using guide lines from The Intergovernmental Panel on Climate Change

Ethanol MM gal/yr

Gasoline replacedMM gal/yr

CO2

released

lbs/gal

Carbon saved MMlbs/yr

Carbonsavedtons/yr

7.1 5 19.5 97 48000

Environmental and Safety

Money in CO2 ?

European Union Results in an

additional earning of 1.6Million dollars/year at $35/ton

Figure 4.4.1. EU-ETS carbon trade: spot and future market volatility 2005-2007 (Point Carbon)

Environmental and Safety

Storage Tank labeling

Materials resistant to ethanol corrosion Unplated and Stainless Steel Black Iron Bronze Nonmetallic Thermoset Reinforced Fiberglass Thermo Plastic Piping Neoprene Rubber Nitrile Teflon

Hazard Rating 4-Extreme 3-Severe 2-Moderate 1-Slight 0-Minimal

Health 2

Flammability 3

Reactivity 0

Environmental and Safety

Odor Control Water Scrubber

Off fermentation and any vents that would contain Ethanol

Majority of the CO2 and 0.2% of the ethanol is vented

Contains 83.7% CO2, 12% ethanol, 4% water

Effluent is fed to the first distillation column Over 99% of the ethanol to scrubber is recovered

Recommendations

Further testing on Z. Mobilis Genetically engineered bacteria my not hold up in

SSL New strains could be more effective

Consider yeast Proven to work well with 6 carbon sugars Will lose the fermentation of 5 carbon sugars Rework analysis for 6 carbon sugars alone

Conclusions

Ethanol production = 7.1 MM gal/yr

Net Present Value = $17.3 MM

Assuming mill can handle increase in steam demand

Z. mobilis yield is accurate and is hardy enough for SSL