How Much Wood To Make A Gallon Of Methanol

Experimental methods for converting wood chips and grass into ethanol will soon exist tested at production calibration. Mascoma Corporation, based in Cambridge, MA, is building demonstration facilities that will have the chapters to produce well-nigh one-half to two million gallons of ethanol a twelvemonth from waste product biomass. The startup recently received $xxx million in venture-upper-case letter money, which is fueling its scale-upwards plans.

The inquiry of Lee Lynd, professor of applied science at Dartmouth College and a cofounder of Mascoma Corporation, is helping cut the cost of making ethanol from cellulosic sources such as cornstalks and wood chips.

While Mascoma has non achieved its ultimate goal of using a single genetically engineered organism to convert woods chips and other cellulosic raw materials into ethanol, the company has developed genetically modified leaner that can speed up function of the process of producing ethanol. The optimized procedure shows enough hope to invest in scaling up the technology, says Colin South, Mascoma's president.

Corn grain, the current source of ethanol in the United States, requires big amounts of land and energy to produce. This, along with the demand for corn every bit food, limits the total amount of ethanol that can exist produced from corn to about xv billion gallons a year–almost 3 times what is currently produced. If the fuel is to supervene upon a sizable fraction of the 140 billion gallons of gasoline consumed each year in the United States, ethanol producers will need to plow to biomass such as wood chips and switchgrass. These resources are cheaper and potentially much more than arable, and they can exist converted to ethanol much more efficiently than corn can considering they crave less free energy to grow (come across "Redesigning Life to Brand Ethanol").

Indeed, ethanol from such sources could replace "a very large fraction" of the gasoline currently used for vehicles, says Gregory Stephanopoulos, professor of chemical engineering at MIT. He says some experts gauge that with gains in efficiency and loftier yields of ethanol, all the gasoline for transportation could be replaced; the well-nigh bourgeois estimates say that about 20 percent could exist replaced. Hoping to capitalize on this potential, a handful of companies–including Celunol, in Dedham, MA; Iogen, in Ottawa, Canada, which has an existing demonstration scale plant and plans to calibration up to commercial product; and the National Renewable Energy Laboratory (NREL), in Aureate, CO–are working to develop better engineering science for making cellulosic ethanol.

Despite its potential, cellulosic ethanol is expensive to make today. It requires more than costly equipment and more processing steps than does making ethanol from corn grain. While both corn and cellulosic ethanol are created by fermenting saccharide, converting the starch in corn grain into saccharide is much easier than converting the complex cellulose in cornstalks or biomass such as wood chips. To simplify the procedure and reduce costs, many researchers ultimately hope to engineer a single organism that tin both interruption downwardly the cellulose and convert the resulting sugars into ethanol. But research is already improving parts of the process. For instance, researchers have created a cocktail of enzymes for converting cellulose into sugar that is a hundred times cheaper than previous methods, says George Douglas, spokesman for the NREL.

Mascoma is focusing on improving the starting time steps of the procedure–pretreating raw materials and converting cellulose into sugars–which South says are fundamental to reducing costs. In the conventional pretreatment step, materials such equally wood chips are soaked in a dilute solution of sulfuric acid then heated. This breaks down complex lignin structures that form a "shield" around the cellulose, says Charles Wyman, Mascoma co-founder and professor of chemical and ecology engineering at the University of California, in Riverside. Wyman'southward research has analyzed the mechanisms involved in this process, helping the company optimize this footstep. Mascoma has besides developed technology for improving the next step: breaking down the at present accessible cellulose into sugars by using enzymes produced by organisms. In the latter part of the process, these sugars are fermented to make ethanol.

Wyman estimates that the company'south technology could produce ethanol for about the same cost as producing ethanol from corn, and eventually for less money. This would exist a significant improvement over other technology. A cost analysis at an NREL pilot constitute, for case, suggests that it would cost more than 2 dollars a gallon to make cellulosic ethanol–most double the cost of making corn ethanol. But even NREL researchers are confident that this cost will exist cut in half and encounter corn-ethanol costs within vi years, Douglas says.

Producing enough ethanol to supersede a pregnant fraction of gasoline consumption is still many years away, notwithstanding. Information technology will crave further improving both the technology and the industrial processes, including the challenges that go with handling large amounts of bulky biomass. "Nosotros are definitely not at that place even so," says MIT'due south Stephanopoulos. "Processes today are clearly uneconomical."

Merely Douglas says researchers are optimistic that continued funding and the application of new tools volition make widespread cellulosic ethanol possible: "The pathways are pretty clear."

Source: https://www.technologyreview.com/2006/11/16/227438/making-ethanol-from-wood-chips/

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