Biomass For Ethanol Production Research Articles

エネルギー用サトウキビからの食糧共存型バイオマスエタノール生産

Competition for raw materials between sugar and ethanol usually occurs when biomass ethanol is produced from sugarcane. In order to overcome this critical problem, numerous studies have investigated the production of ethanol from two by-products of sugarcane: molasses and bagasse. However, there have been no previous attempts to improve the relevant properties of sugarcane, such as its growth rate, sugar content or fiber content.The objective of the current work was to develop a novel system for high-yield biomass ethanol production to support existing methods of sugar production. A system for the simultaneous production of sugar and biomass ethanol was designed by employing selected sugarcane strains that were developed specifically for this process, including 95GA-24, 95GA-27 and NiTn18.We ran productivity simulations using data from the novel sugarcane strains and compared the per-formance of the new process with that of conventional methods. Our results confirmed that sugar produc-tion could be maintained at present levels while three-times more biomass ethanol could be generated com-pared with the conventional processes. In addition, we demonstrated that a carbon-neutral process could be achieved using the new system.

バイオマスエタノール生産プロセスにおける廃水リサイクル(新エネルギー(2),空気調和・冷凍・エネルギー有効利用技術)

Biomass ethanol is remarkable as the 'carbon neutral' fuel because it does not increase atmospheric CO2 concentration. We constructed a pilot scale biomass ethanol production plant using house wood as the feed stock. The waste water generated from biomass ethanol production process has a dark color originated from lignin or sugar degradation products. Since this color cannot be removed by biological treatment, other suitable treatment process must be adopted. Reduction of water treatment cost is also important. Recycling the waste water is one of the suitable ways to reduce the water treatment cost. But inhibition of fermentation is concerned which would be occurred by impurities originated from house wood and concentrated during the recycle. In this study we evaluated some water treatment method for biomass ethanol process. We also calculated the concentration ratio caused by waste water recycling and investigated the inhibition of fermentation.

Ethanol recovery from corn fiber hydrolysate fermentations by pervaporation

Corn fiber, a byproduct of corn wet milling, is an attractive feedstock for biomass ethanol production. Corn fiber was hydrolyzed by dilute sulfuric acid and neutralized by one of two methods: conventional lime treatment or neutralization by strongly basic anion exchange. The anion exchange neutralized (AEN) hydrolysate contained substantially lower levels of the inhibiting compounds furfural, 5-hydroxymethylfurfural, and acetic acid compared to the lime neutralized hydrolysate. In batch fermentations the ethanol yields and final ethanol concentration of the two hydrolysates were similar at 0.32–0.43 g/g and 29–44 g/l, respectively. Sugar consumption in the AEN fermentations was superior. Coupling of a membrane pervaporation unit to a fed-batch fermentation of AEN hydrolysate maintained the ethanol concentration below 25 g/l with complete sugar utilization for approximately 5 days. A concentrated ethanol stream of 17 wt.% ethanol was produced by the pervaporation unit.

BIOMASSETHANOL: Technical Progress, Opportunities, and Commercial Challenges

▪ Abstract Ethanol made from lignocellulosic biomass sources, such as agricultural and forestry residues and herbaceous and woody crops, provides unique environmental, economic, and strategic benefits. Through sustained research funding, primarily by the U.S. Department of Energy, the estimated cost of biomass ethanol production has dropped from ∼$4.63/gallon in 1980 to ∼$1.22/gallon today, and it is now potentially competitive for blending with gasoline. Advances in pretreatment by acid-catalyzed hemicellulose hydrolysis and enzymes for cellulose breakdown coupled with recent development of genetically engineered bacteria that ferment all five sugars in biomass to ethanol at high yields have been the key to reducing costs. However, through continued advances in accessing the cellulose and hemicellulose fractions, the cost of biomass ethanol can be reduced to the point at which it is competitive as a pure fuel without subsidies. A major challenge to realizing the great benefits of biomass ethanol remains to substantially reduce the risk of commercializing first-of-a-kind technology, and greater emphasis on developing a fundamental understanding of the technology for biomass conversion to ethanol would reduce application costs and accelerate commercialization. Teaming of experts to cooperatively research key processing steps would be a particularly powerful and effective approach to meeting these needs.

Combined heat treatment and acid hydrolysis of cassava grate waste (CGW) biomass for ethanol production

The effect of combined heat treatment and acid hydrolysis (various concentrations) on cassava grate waste (CGW) biomass for ethanol production was investigated. At high concentrations of H 2SO 4 (1–5 m), hydrolysis of the CGW biomass was achieved but with excessive charring or dehydration reaction. At lower acid concentrations, hydrolysis of CGW biomass was also achieved with 0.3–0.5 m H 2SO 4, while partial hydrolysis was obtained below 0.3 m H 2SO 4 (the lowest acid concentration that hydrolysed CGW biomass) at 120°C and 1 atm pressure for 30 min. A 60% process efficiency was achieved with 0.3 m H 2SO 4 in hydrolysing the cellulose and lignin materials present in the CGW biomass. High acid concentration is therefore not required for CGW biomass hydrolysis. The low acid concentration required for CGW biomass hydrolysis, as well as the minimal cost required for detoxification of CGW biomass because of low hydrogen cyanide content of CGW biomass would seem to make this process very economical. From three litres of the CGW biomass hydrolysate obtained from hydrolysis with 0.3 m H 2SO 4, ethanol yield was 3.5 (v/v %) after yeast fermentation. However, although the process resulted in gainful utilization of CGW biomass, additional costs would be required to effectively dispose new by-products generated from CGW biomass processing.

Future potential for MSW energy development

This work examines the potential supply of municipal solid waste (MSW) which could be used to support new (not existing or currently planned) energy capacity in the year 2000. The resource we are interested in is MSW which is not recycled or burned; which would be landfilled unless new MSW energy conversion capacity is constructed. A detailed analysis of MSW composition by individual components was used for 1990 and 2000. For each component of MSW we estimated heat content, ethanol yield and recycling efficiencies. From these data, we estimated how much MSW could be diverted from landfills to either new biomass-ethanol or new MSW-electricity plants. We also estimated where these new MSW-energy plants could be located. The impact of the planned growth in the MSW-power industry between 1992 and 1995 and higher material recycling rates have a significant effect on the supply of MSW in the year 2000. The implications of these changes are discussed in the context of the solid waste management industry. Some of the possible changes discussed include: • • declining amounts of MSW available after recycling will increase competition for MSW between and within power producers, recyclers and landfill firms, especially along the Eastern seaboard • • more competition for MSW may lead to lower tipping fees in the future • • as recycling efficiencies increase, MSW-power producers will need to attract MSW from further and further away to maintain capacity, causing transportation costs to rise • • the composition of materials reaching landfills may change if a large amount of MSW is consumed to produce energy, and landfill closures may be rendered moot. • • some areas of the country may not be suitable for building MSW-energy facilities in today, because by the year 2000, these areas may be in short supply of MSW. The analysis revealed that from 15.5 million to 71.7 million tonnes of new MSW power capacity could is be added by 2000, depending on the recycling scenario; if MSW is used for biomass-ethanol production, from 11.6 million to 31.6 million tonnes of MSW ethanol capacity in the year 2000.

Analysis of internal and external energy flows associated with projected process improvements in biomass ethanol production

Possible improvements in biomass ethanol production are decribed involving heat-pumped distillation, steam-cycle heat integration, elimination of seed fermenters, pretreatment heat integration, advanced pretreatment, thermophilic DMC, and incrased carbohydrate yield to 90% of theoretical. Although speculative, a futuristic process incorporating these improvements may be useful for anticipating some features of a technologically mature biomass ethanol process, as well as for comparing ethanol production to more technologically mature energy-conversion processes. Relative to the current state-of-the-art National Renewable Energy Laboratory process design, the futuristic process has 101% higher electricity revenue, 31% hgiher ethanol revenue, and 35–39% higher overall revenue depending on the assumed ethanol value. The overall first-law thermodynamic efficiency is 43% for the current NREL design and 59% for the futuristic process. A general consideration of the costs associated with the process improvements examined indicates that: 1. Elimination of seed reactors, advanced pretreatment, and thermophilic DMC all have large potential cost reductions independent of their benefits with respect to increased surplus electricity; 2. Steam cycle improvements and pretreatment heat integration are expected to have modest cost benefits that are dependent on increased electricity revenues; and 3. The relative cost of heat-pumped distillation depends on scale, capital recovery, and electricity value, but is generally similar to the already low cost of conventional distillation provided that the fermentation broth has a reasonably high ethanol concentration.