Background and Motivation
КОНТРОЛЬНЫЙ ПИСЬМЕННЫЙ ПЕРЕВОД
НАУЧНОГО ТЕКСТА ПО СПЕЦИАЛЬНОСТИ
« Process Design and Economics for Biochemical Conversion of Lignocellulosic Biomass» byD. Humbird, R. Davis, L. Tao, C. Kinchin, D. Hsu, and A. Aden.
« Проектирование процессов и экономика для биохимического преобразования Лигноцеллюлозных биомассы» автор Д. Хамберда, Р. Дэвиса, Л. Тао, К. Кинчина, Д. Хсу и А. Адена.
Студент 1 курса, группы 327(В)-М22 кафедры экономики
Бозоров Сафарали Амиршоевич
Кандидат экономических наук
Алексеева Юлия Александровна
Кандидат педагогических наук, старший преподаватель кафедры
«Иностранные языки в профессиональной
Волкова Елена Вячеславовна
Казань – 2017 г.
1. Текст оригинала…………………………………………….………. 3
2. Перевод текста на русский язык……………………………………. 9
3. Терминологический словарь………………………………………... 17
Process Design and Economics for Biochemical Conversion of Lignocellulosic Biomass
This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof.
Background and Motivation
The U.S. Department of Energy (DOE) Office of the Biomass Program (OBP) promotes the production of ethanol and other liquid fuels from lignocellulosic feedstocks by sponsoring programs in fundamental and applied research that aim to advance the state of biomass conversion technology. These programs include laboratory campaigns to develop better cellulose hydrolysis enzymes and fermenting microorganisms, detailed engineering studies of potential processes, and construction of pilot-scale demonstration and production facilities. This research is conducted by national laboratories, universities, and private industry in conjunction with engineering and construction companies.
As part of its involvement in the program, the National Renewable Energy Laboratory (NREL) investigates the complete process design and economics of cellulosic ethanol manufacturing in order to develop an absolute plant-gate price for ethanol based on process and plant design assumptions consistent with applicable best practices in engineering, construction, and operation. This plant-gate price is referred to as the minimum ethanol selling price or MESP. The MESP can be used by policymakers and DOE to assess the cost-competitiveness and market penetration potential of cellulosic ethanol in comparison with petroleum-derived fuels and starch- or sugar-based ethanol.
The technoeconomic analysis effort at NREL also helps to direct our biomass conversion research by examining the sensitivity of the MESP to process alternatives and research advances. Proposed research and its anticipated results can be translated into a new MESP that can be compared to the benchmark case documented in this report. Such comparison helps to quantify the economic impact of core research targets at NREL and elsewhere and to track progress toward meeting competitive cost targets. It also allows DOE to make more informed decisions about research proposals that claim to reduce MESP.
This report builds upon previous issues from 1999 and 2002 written by NREL engineers with Delta-T, Merrick Engineering, Reaction Engineering, Inc., and Harris Group. For the present report, NREL again contracted Harris Group to provide engineering support for estimating and reviewing the equipment and raw material costs used in the process design. This update reflects NREL’s latest envisioned biochemical ethanol process and includes recent research progress in the conversion areas (pretreatment, conditioning, enzymatic hydrolysis, and fermentation), optimizations in product recovery, and our latest understanding of the ethanol plant’s back end (separation, wastewater, and utilities). NREL worked with Harris Group to identify realistic configurations and costs for critical equipment, the pretreatment reactor system in particular. An on-site cellulase enzyme section was included in this update to permit better transparency of enzyme economics than the fixed cost contribution assumed in the last design report did.
The biomass conversion efficiencies used in the design (e.g., cellulose to glucose or xylose to ethanol) are based on a slate of research targets that NREL and DOE have committed to demonstrate by the end of 2012 in a campaign of integrated pilot-scale runs. These 2012 performance targets are discussed in detail in this report. The economics of this conceptual process use the best available equipment and raw material costs and an “nth-plant” project cost structure and financing. The projected 2012 nth-plant MESP computed in this report is $2.15/gal in 2007$.
Modifications to the conceptual process design presented here will be reflected annually through NREL’s State of Technology (SOT) reports. These ensure that the process design and its cost benchmark incorporate the most current data from NREL and other DOE-funded research and that equipment costs stay up-to-date.
We stress that this design report serves to describe a single, feasible cellulosic ethanol conversion process and to transparently document the assumptions and details that went into its design. This report is not meant to provide an exhaustive survey of process alternatives or cost-sensitivity analyses. These will be investigated in separate papers that extend and reference the present report. Furthermore, the process models and economic tools developed for this report are available to the public, and the authors and members of NREL’s Biochemical Platform Analysis task will provide support to researchers who wish to use them for their own studies.
The process described here uses co-current dilute-acid pretreatment of lignocellulosic biomass (corn stover), followed by enzymatic hydrolysis (saccharification) of the remaining cellulose, followed by fermentation of the resulting glucose and xylose to ethanol. The process design also includes feedstock handling and storage, product purification, wastewater treatment, lignin combustion, product storage, and required utilities. The process is divided into nine areas :
• Area 100: Feed handling. The feedstock, in this case milled corn stover, is delivered to the feed handling area from a uniform-format feedstock supply system. Only minimum storage and feed handling are required. From there, the biomass is conveyed to the pretreatment reactor (Area 200).
• Area 200: Pretreatment and conditioning. In this area, the biomass is treated with dilute sulfuric acid catalyst at a high temperature for a short time to liberate the hemicelluloses sugars and break down the biomass for enzymatic hydrolysis. Ammonia is then added to the whole pretreated slurry to raise its pH from ~1 to ~5 for enzymatic hydrolysis.
• Area 300: Enzymatic hydrolysis and fermentation. Enzymatic hydrolysis is initiated in a high-solids continuous reactor using a cellulase enzyme prepared on-site. The partially hydrolyzed slurry is next batched to one of several parallel bioreactors. Hydrolysis is completed in the batch reactor, and then the slurry is cooled and inoculated with the cofermenting microorganism Zymomonas mobilis. After a total of five days of sequential enzymatic hydrolysis and fermentation, most of the cellulose and xylose have been converted to ethanol. The resulting beer is sent to the product recovery train (Area 500).
• Area 400: Cellulase enzyme production. An on-site enzyme production section was included in this design. Purchased glucose (corn syrup) is the primary carbon source for enzyme production. Media preparation involves a step in which a portion of the glucose is converted to sophorose to induce cellulase production. The enzyme-producing fungus (modeled after Trichoderma reesei) is grown aerobically in fed-batch bioreactors. The entire fermentation broth, containing the secreted enzyme, is fed to Area 300 to carry out enzymatic hydrolysis.
• Area 500: Product recovery. The beer is separated into ethanol, water, and residual solids by distillation and solid-liquid separation. Ethanol is distilled to a nearly azeotropic mixture with water and then purified to 99.5% using vapor-phase molecular sieve adsorption. Solids recovered from the distillation bottoms are sent to the combustor (Area 800) while the liquid is sent to wastewater treatment (Area 600).
• Area 600: Wastewater treatment. Plant wastewater streams are treated by anaerobic and aerobic digestion. The methane-rich biogas from anaerobic digestion is sent to the combustor (Area 800), where sludge from the digesters is also burned. The treated water is suitable for recycling and is returned to the process.
• Area 700: Storage. This area provides bulk storage for chemicals used and produced in the process, including corn steep liquor (CSL), ammonia, sulfuric acid, nutrients, water, and ethanol.
• Area 800: Combustor, boiler, and turbogenerator. The solids from distillation and wastewater treatment and the biogas from anaerobic digestion are combusted to produce high-pressure steam for electricity production and process heat. The majority of the process steam demand is in the pretreatment reactor and distillation columns. The boiler produces excess steam that is converted to electricity for use in the plant and for sale to the grid.
• Area 900: Utilities. This area includes a cooling water system, chilled water system, process water manifold, and power systems.