New process design improves energy balance of ethanol production considerably
Using the sheer power of mathematical programming, chemical engineers from the Carnegie Mellon University in the U.S. have devised a new process that considerably improves the efficiency of ethanol production, a major component in making biofuels a significant part of the world's energy supply.
The researchers have used advanced process design methods combined with mathematical optimization techniques to reduce the operating costs of corn-based bioethanol plants by more than 60 percent. The key to the new strategy involves redesigning the distillation process by using a multi-column system together with a network for energy recovery that ultimately reduces the consumption of steam, a major energy component in the production of corn-based ethanol.
For a long time, corn-based ethanol was considered a questionable energy resource, and doubts still remain over its final energy balance (for more on this concept, see the excellent overview of the principles behind the notion of 'net energy' at the Encyclopedia of Earth, and a new lifecycle assessment of corn ethanol's energy efficiency). Today, 46 percent of all U.S. gasoline contains some percentage of ethanol. Until now, demand was driven by a federal mandate that 5 percent of the American gasoline supply – roughly 7.5 billion gallons – contain some ethanol by 2012.
But since President Bush held his State of the Union address, the biofuel has received a far bigger boost. The new U.S. energy agenda aims to replace not less than 20% of all gasoline consumption (roughly 2 million barrels per day) with renewables, mainly ethanol, in 10 years time ("20 in 10") (earlier post). This will require a gigantic investment in finite resources, and so each increase in processing efficiencies is more than welcome.
biomass :: bioenergy :: biofuels :: energy :: sustainability :: process systems engineering :: energy efficiency :: energy recovery :: ethanol :: distillation :: energy balance :: EROEI ::
The research was conducted through the Chemical Engineering Department's Center of Advanced Process Decision-Making in collaboration with Minneapolis-based Cargill, an international provider of food, agricultural and risk management services and products. More particularly, it drew on the work of Professor Grossman's team, which is united in a research group, whose main aim is the development of discrete-continuous optimization models and methods for problems in process systems engineering.
Grossman's group addresses "problems in the areas of process synthesis, planning and scheduling of process systems, through novel mathematical programming approaches, which rely on linear and nonlinear models with discrete and continuous variables. These include mixed-integer programming (MILP and MINLP), General Disjunctive Programming (GDP) and global optimizationand multiperiod optimization. Both deterministic models as well as models with uncertainty are considered."
Luca C. Zullo, technical director of Cargill Emissions Reduction Services, said about the cooperation: "As a result of the explosive growth of the U.S. fuel ethanol industry, we decided to collaborate with Professor Grossmann's team to verify how process synthesis tools could be applied to improve the production of ethanol from corn. The work done at Carnegie Mellon demonstrated the potential for considerable capital and energy cost savings in the corn to ethanol process. We look forward to the time when the tools developed by Carnegie Mellon researchers will become part of industry's new toolkit for making the process even more economical and sustainable."
Efficiency increases in biofuel processing are one of the areas in which tremendous progress remains to be made. An example of what is possible is offered by Brazil's experience. There, in less than 25 years time, ethanol producers succeeded in reducing costs by up to 75%, mainly through increases in processing efficiency. This trend is set to continue, making the energy balance of the biofuel better than it already is.
Without wanting to be be too deterministic (or assuming the existence of some hidden finality within scientific evolution), the exponential increase in scientific and technological breakthroughs allows us to assume that in the field of biofuels production too, large efficiency increases will be made in the not so distant future (in plant biology, agronomy, engineering, biochemistry and process engineering).
More information:
Barttfeld, M., Aguirre, P.A. and Grossmann, I.E. "A Decomposition Method for Synthesizing Complex Column Configurations Using Tray-by-Tray GDP Models," [*.pdf], sine dato, submitted for publication.
Barttfeld M., Aguirre P.A. and Grossmann I.E. "Alternative Representations and Formulations for the Economic Optimization of Multicomponent Distillation Columns." [*.pdf] To appear in Computers & Chemical Engineering.
Cleveland, Cutler; Peter Saundry, 2007. "Ten fundamental principles of net energy." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment).
Article continues
The researchers have used advanced process design methods combined with mathematical optimization techniques to reduce the operating costs of corn-based bioethanol plants by more than 60 percent. The key to the new strategy involves redesigning the distillation process by using a multi-column system together with a network for energy recovery that ultimately reduces the consumption of steam, a major energy component in the production of corn-based ethanol.
For a long time, corn-based ethanol was considered a questionable energy resource, and doubts still remain over its final energy balance (for more on this concept, see the excellent overview of the principles behind the notion of 'net energy' at the Encyclopedia of Earth, and a new lifecycle assessment of corn ethanol's energy efficiency). Today, 46 percent of all U.S. gasoline contains some percentage of ethanol. Until now, demand was driven by a federal mandate that 5 percent of the American gasoline supply – roughly 7.5 billion gallons – contain some ethanol by 2012.
But since President Bush held his State of the Union address, the biofuel has received a far bigger boost. The new U.S. energy agenda aims to replace not less than 20% of all gasoline consumption (roughly 2 million barrels per day) with renewables, mainly ethanol, in 10 years time ("20 in 10") (earlier post). This will require a gigantic investment in finite resources, and so each increase in processing efficiencies is more than welcome.
"This new design reduces the manufacturing cost for producing ethanol by 11 percent, from $1.61 a gallon to $1.43 a gallon. This research also is an important step in making the production of ethanol more energy efficient and economical." Chemical Engineering Professor Ignacio E. Grossmann, who completed the research with graduate students Ramkumar Karuppiah, Andreas Peschel and Mariano Martin.In the U.S., corn is the main feedstock used to produce ethanol, but the biofuel can be made from a wide variety of starch and sugar rich crops. The increased efficiency derived from the enhanced energy recovery model can in principle be applied to most other processing facilities:
biomass :: bioenergy :: biofuels :: energy :: sustainability :: process systems engineering :: energy efficiency :: energy recovery :: ethanol :: distillation :: energy balance :: EROEI ::
The research was conducted through the Chemical Engineering Department's Center of Advanced Process Decision-Making in collaboration with Minneapolis-based Cargill, an international provider of food, agricultural and risk management services and products. More particularly, it drew on the work of Professor Grossman's team, which is united in a research group, whose main aim is the development of discrete-continuous optimization models and methods for problems in process systems engineering.
Grossman's group addresses "problems in the areas of process synthesis, planning and scheduling of process systems, through novel mathematical programming approaches, which rely on linear and nonlinear models with discrete and continuous variables. These include mixed-integer programming (MILP and MINLP), General Disjunctive Programming (GDP) and global optimizationand multiperiod optimization. Both deterministic models as well as models with uncertainty are considered."
Luca C. Zullo, technical director of Cargill Emissions Reduction Services, said about the cooperation: "As a result of the explosive growth of the U.S. fuel ethanol industry, we decided to collaborate with Professor Grossmann's team to verify how process synthesis tools could be applied to improve the production of ethanol from corn. The work done at Carnegie Mellon demonstrated the potential for considerable capital and energy cost savings in the corn to ethanol process. We look forward to the time when the tools developed by Carnegie Mellon researchers will become part of industry's new toolkit for making the process even more economical and sustainable."
Efficiency increases in biofuel processing are one of the areas in which tremendous progress remains to be made. An example of what is possible is offered by Brazil's experience. There, in less than 25 years time, ethanol producers succeeded in reducing costs by up to 75%, mainly through increases in processing efficiency. This trend is set to continue, making the energy balance of the biofuel better than it already is.
Without wanting to be be too deterministic (or assuming the existence of some hidden finality within scientific evolution), the exponential increase in scientific and technological breakthroughs allows us to assume that in the field of biofuels production too, large efficiency increases will be made in the not so distant future (in plant biology, agronomy, engineering, biochemistry and process engineering).
More information:
Barttfeld, M., Aguirre, P.A. and Grossmann, I.E. "A Decomposition Method for Synthesizing Complex Column Configurations Using Tray-by-Tray GDP Models," [*.pdf], sine dato, submitted for publication.
Barttfeld M., Aguirre P.A. and Grossmann I.E. "Alternative Representations and Formulations for the Economic Optimization of Multicomponent Distillation Columns." [*.pdf] To appear in Computers & Chemical Engineering.
Cleveland, Cutler; Peter Saundry, 2007. "Ten fundamental principles of net energy." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment).
Article continues
Saturday, January 27, 2007
Anthropological study explores the effects of genetically modified crops on developing countries
But some fear this green, clean and climate-friendly economy will increasingly rely on the use of genetically modified organisms (GMOs). Considerable research is currently going into the development of crops that yield more biomass that can be converted easily into useful products (from fuels to plastics) or in to plants that withstand previously unsuitable agro-climatic conditions.
So far, the developing world has already had its fair share of experiences with GMOs. But very few studies have actually looked at the long-term economic, social and cultural impacts of these crops on the farming communities who cultivate them. Often, social and environmental impact assessments are written in a routine, standard fashion (by the companies that sell the crops), or they are ideologically burdened because written by (Western) NGOs with a narrow, ethnocentric agenda. The analytical tools used in such studies are often of dubious quality, not to say outright superficial.
In such a climate, the scientific, deep, ethnographic gaze of the social anthropologist is more than welcome. A new study in the February issue of Current Anthropology explores how the arrival of genetically modified crops affects peasants in developing countries. Glenn Davis Stone, professor of anthropology and environment at Washington University, carried out a multi-year ethnography of farmers the Warangal District of Andhra Pradesh in India, a key cotton growing area notorious for suicides by cotton farmers.
In 2003 to 2005, market share of "Bt cotton" seeds rose from 12 percent to 62 percent in Warangal. Bt cotton is genetically modified to produce its own insecticide and has been claimed by its manufacturer as the fastest-adopted agricultural technology in history.
Monsato, the firm behind Bt cotton, has interpreted the rapid spread of the modified strain as the result of farmer experimentation and management skill � similar to mechanisms that scholars cite to explain the spread of hybrid corn across American farms. But Stone's multiyear ethnography of Warangal cotton farmers shows an unexpected pattern of localized cotton seed fads in the district. He argues that, rather than a case of careful assessment and adoption, Warangal is plagued by a severe breakdown of the "skilling" process by which farmers normally hone their management practices:
biomass :: bioenergy :: biofuels :: energy :: developing world :: agriculture :: genetically modified organisms :: environmental sustainability :: social sustainability :: anthropology :: ethnography :: Andhra Pradesh ::
"Warangal cotton farming offers a case study in 'agricultural deskilling'," writes Stone. The seed fads had virtually no environmental basis, and farmers generally lacked recognition of what was actually being planted, a striking contrast to highly strategic seed selection processes in areas where technological change is learned and gradual. Interviews also provided consistent evidence that Warangal cotton farmers prefer trying new seeds - seeds without any background information whatsoever - to trying several strains on smaller, experimental scales and choosing one for long-term adoption.
The problem preceded Bt cotton, Stone points out; its root causes are reliance on hybrid seed, which must be repurchased every year, and a chaotic seed market in which products come and go at a furious pace and farmers often cannot tell what they are using. Farmer desire for novelty exacerbates the turnover of seeds in the market, Stone argues, and seed firms will frequently take seeds that have fallen out of favor, rename them, and resell with new marketing campaigns. For instance, one recent favorite seed in several villages is identical to four other seeds on the market.
Stone argues that the previously undocumented pattern of fads, in which each village lurches from seed to seed, reflects a breakdown of the process of "environmental learning," leaving farmers to rely purely on "social learning." Bt cotton was not the cause of this "deskilling," but in Warangal it has exacerbated the problem.
"On the surface, [Warangal] appears to be a dramatic case of successful adoption of an innovation," Stone explains. "However, a closer analysis of the dynamics of adoption shows that the pattern some see as an environmentally based change in agricultural practice actually continues the established pattern of socially driven fads arising in the virtual absence of environmental learning."
Strangely, in another part of India, a very different history of Bt cotton has led to an improvement in agricultural skilling. In Gujarat, the loss of corporate control over the Bt technology has led to an increased involvement of farmers in local breeding, and an apparent increase in knowledge-based innovation.
We will be needing this kind of studies much more in the future. The introduction of bioenergy and biofuel production is not merely a technological or economic matter. Instead, it is caught up in the dense realities of social structures and cultural change. An anthropological approach to studying the ways local cultures perceive and deal with the introduction of new energy paradigms, markets and products, implies that we are willing to question our own ideas on 'modernisation', 'technological progress', and 'development'.
Too often, the institutions involved in 'development' (governments, corporations, international development agencies, NGOs) still rely on a 'top down' and ethnocentric vision when they assess the effects of the projects they (are planning to) implement. Despite their attempts to include as many 'stake-holders' into their sustainability analyses, such assessments seldom reflect the deeper social and cultural realities of the people in question. This is one of the reasons why so many development projects ultimately fail, provoke resistance or end up being damaging.
For this reason we need analysts, like anthropologists and ethnographers, who can 'translate' the way cultural systems deal with social and economic change. This is especially true in the field of large-scale bioenergy projects in the South, which affect a complex set of interacting socio-cultural factors: from views on land ownership and patterns of local power, to migration and labor dynamics. No company, government or development agency can afford to side-step a thorough anthropological analysis of these interacting factors.
Picture: Farmers buying cotton seeds at a shop in Warangal. Visible behind them are a few of the many hybrid seeds available at the shop. The man in the middle is paying 1600 rupiah a pack of RCH2-Bt (4 times the cost of conventional seed). When asked why he had chosen RCH2-Bt, he said it was what other farmers were buying. Courtesy Glenn Davis Stone.
More information:
Glenn Davis Stone, "Agricultural Deskilling and the Spread of Genetically Modified Cotton in Warangal", Current Anthropology, Volume 48, Number 1, February 2007 - abstract.
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