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Section 2. ANIMAL/AGRICULTURAL WASTES USE OF METHANE GAS FROM ANAEROBIC TREATMENT OF STILLAGE FOR FUEL ALCOHOL PRODUCTION Enos L. Stover, Professor Ganapathi Gomathinayagam, Graduate Student Reinaldo Gonzalez, Graduate Student Bioenvironmental and Water Resources Engineering School of Civil Engineering Oklahoma State University Stillwater, Oklahoma 74078 INTRODUCTION In recent years fermentation of ethanol from agricultural feed stocks, such as corn and milo, has been demonstrated to be a promising energy alternative for the United States. Gasohol, a blend of 10% anhydrous ethanol and 90% unleaded gasoline, has been shown to be compatible with 100% unleaded gasoline and has received widespread public acceptance. However, the gasohol industry has been plagued with many problems, and in this day and time of economic turmoil and energy shortages, a fledgling industry such as the fuel alcohol industry must capitalize on every economic advantage available. Two very serious problems of this industry center around the energy consumption requirements to produce the alcohol and the production of high-temperature, high-strength, acidic wastewaters called thin stillage. Heat energy is required at every stage of the production process including grain drying, cooking, saccharification, fermentation, and distillation. Unless careful design and operation constraints are imposed, the energy consumption per gallon of alcohol produced can be greater than the energy available from one gallon of alcohol. Thus, the total energy balance around the production plant becomes a critical factor, and innovative improvements to reduce the total process energy demands are needed. Ethanol production by fermentation also requires considerable quantities of water with substantial amounts ending up in the thin stillage as wastewater. Although a portion of this water can be recycled, complete reuse is generally not possible due to the build-up of salts and toxic by-products of the fermentation reactions. These high strength wastewaters can be treated biologically to high treatment efficiencies in both aerobic and anaerobic systems [1,2,3,4]. The anaerobic systems offer the advantage of methane gas production which can be used as a fuel source back in the alcohol production process. Independently, the two problems described in the previous paragraph can have a significant negative impact on the cost of fuel alcohol production. However, when considered jointly, a synergistic effect can be realized by application of anaerobic treatment of the stillage and use of the methane gas produced to supplement the fuel requirements of the alcohol plant. Research at Oklahoma State University with both fixed-film and suspended growth anaerobic treatment systems has demonstrated very high treatment efficiencies of thin stillage. The biological treatment kinetics and methane production rates have been defined such that full-scale facilities can be designed and operated for reliable methane production. The impacts of employing anaerobic treatment at a one million gallon per year alcohol production plant and utilizing the methane gas from treatment of the thin stillage have been evaluated. The results of this investigation are presented in the following sections. ALCOHOL PRODUCTION Material and energy balances were conducted around a small commercial or industrial ethanol (fuel alcohol) plant capable of producing one million gallons of anhydrous ethanol (200 proof) per year. When operating 24 hours per day for 300 days out of the year at the production rate of 150 gallons per hour (3,600 gallons per day), this plant can produce one million gallons of pure ethanol per year. The feedstock consists of corn and milo, and under good operating and management 57
Object Description
Purdue Identification Number | ETRIWC198408 |
Title | Use of methane gas from anaerobic treatment of stillage for fuel alcohol production |
Author |
Stover, Enos L. Gomathinayagam, Ganapathi Gonzalez, Reinaldo |
Date of Original | 1984 |
Conference Title | Proceedings of the 39th Industrial Waste Conference |
Extent of Original | p. 57-64 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-07-16 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 57 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | Section 2. ANIMAL/AGRICULTURAL WASTES USE OF METHANE GAS FROM ANAEROBIC TREATMENT OF STILLAGE FOR FUEL ALCOHOL PRODUCTION Enos L. Stover, Professor Ganapathi Gomathinayagam, Graduate Student Reinaldo Gonzalez, Graduate Student Bioenvironmental and Water Resources Engineering School of Civil Engineering Oklahoma State University Stillwater, Oklahoma 74078 INTRODUCTION In recent years fermentation of ethanol from agricultural feed stocks, such as corn and milo, has been demonstrated to be a promising energy alternative for the United States. Gasohol, a blend of 10% anhydrous ethanol and 90% unleaded gasoline, has been shown to be compatible with 100% unleaded gasoline and has received widespread public acceptance. However, the gasohol industry has been plagued with many problems, and in this day and time of economic turmoil and energy shortages, a fledgling industry such as the fuel alcohol industry must capitalize on every economic advantage available. Two very serious problems of this industry center around the energy consumption requirements to produce the alcohol and the production of high-temperature, high-strength, acidic wastewaters called thin stillage. Heat energy is required at every stage of the production process including grain drying, cooking, saccharification, fermentation, and distillation. Unless careful design and operation constraints are imposed, the energy consumption per gallon of alcohol produced can be greater than the energy available from one gallon of alcohol. Thus, the total energy balance around the production plant becomes a critical factor, and innovative improvements to reduce the total process energy demands are needed. Ethanol production by fermentation also requires considerable quantities of water with substantial amounts ending up in the thin stillage as wastewater. Although a portion of this water can be recycled, complete reuse is generally not possible due to the build-up of salts and toxic by-products of the fermentation reactions. These high strength wastewaters can be treated biologically to high treatment efficiencies in both aerobic and anaerobic systems [1,2,3,4]. The anaerobic systems offer the advantage of methane gas production which can be used as a fuel source back in the alcohol production process. Independently, the two problems described in the previous paragraph can have a significant negative impact on the cost of fuel alcohol production. However, when considered jointly, a synergistic effect can be realized by application of anaerobic treatment of the stillage and use of the methane gas produced to supplement the fuel requirements of the alcohol plant. Research at Oklahoma State University with both fixed-film and suspended growth anaerobic treatment systems has demonstrated very high treatment efficiencies of thin stillage. The biological treatment kinetics and methane production rates have been defined such that full-scale facilities can be designed and operated for reliable methane production. The impacts of employing anaerobic treatment at a one million gallon per year alcohol production plant and utilizing the methane gas from treatment of the thin stillage have been evaluated. The results of this investigation are presented in the following sections. ALCOHOL PRODUCTION Material and energy balances were conducted around a small commercial or industrial ethanol (fuel alcohol) plant capable of producing one million gallons of anhydrous ethanol (200 proof) per year. When operating 24 hours per day for 300 days out of the year at the production rate of 150 gallons per hour (3,600 gallons per day), this plant can produce one million gallons of pure ethanol per year. The feedstock consists of corn and milo, and under good operating and management 57 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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