History (from Wikipedia)

The first attempt at commercializing a process for ethanol from wood was done in Germany in 1898. It involved the use of dilute acid to hydrolyze the cellulose to glucose, and was able to produce 7.6 liters of ethanol per 100 kg of wood waste (18 gal per ton). The Germans soon developed an industrial process optimized for yields of around 50 gallons per ton of biomass. This process soon found its way to the United States, culminating in two commercial plants operating in the southeast during World War I. These plants used what was called "the American Process" — a one-stage dilute sulfuric acid hydrolysis. Though the yields were half that of the original German process (25 gallons of ethanol per ton versus 50), the throughput of the American process was much higher. A drop in lumber production forced the plants to close shortly after the end of World War I. In the meantime, a small, but steady amount of research on dilute acid hydrolysis continued at the USDA's Forest Products Laboratory.

In 1932, the Germans developed an improved "percolation" process using dilute sulfuric acid, known as the "Scholler Process." These reactors were simple systems in which a dilute solution of sulfuric acid was pumped through a bed of wood chips. Several years into World War II, the United States found itself facing shortages of ethanol and sugar crops. The U.S. War Production Board reinvigorated research on wood-to-ethanol as an "insurance" measure against future worsening shortages, and even funded construction of a plant in Springfield, OR. The board directed the Forest Products lab to look at improvements in the Scholler Process. Their work resulted in the Madison Wood Sugar process, which showed substantial improvements in productivity and yield over its German predecessor3. Problems with start up of the Oregon plant prompted additional process development work on the Madison process at TVA's Wilson Dam facility. TVA's pilot plant studies further refined the process by increasing yield and simplifying mechanical aspects of the process4. The dilute acid hydrolysis percolation reactor, culminating in the design developed in 1952, is still one of the simplest means of producing sugars from biomass. It is a benchmark against which we often compare our new ideas. In fact, such systems are still operating in Russia.

In the late 1970s, a renewed interest in this technology took hold in the United States because of the petroleum shortages experienced in that decade. Modeling and experimental studies on dilute hydrolysis systems were carried out during the first half of the 1980s. DOE and USDA sponsored much of this work. By 1985, most researchers recognized that, while the dilute acid percolation designs were well understood, these systems had reached the limits of their potential. Their comparatively high glucose yields (around 70%) were achieved at the expense of producing highly dilute sugar streams. Kinetic models, based on pseudo first order kinetics, and process design work showed that the most effective designs would require both high solids concentration and some form of countercurrent flow. The former is a consequence of equipment size and energy cost and the latter is a consequence of the reactor kinetics. Both requirements involve significant equipment design problems. Studies shifted to alternative designs, such as plug flow reactors5,6 and so-called progressing batch systems that mimicked countercurrent operation7. Optimal operation of the plug flow reactors required very short residence time (6 to 10 seconds) and high temperature (around 240 C)8. On scale up, these systems encountered some difficulties with solids handling, even at lower-than-optimal concentrations9. Plug flow systems in the lab and the pilot plant produced yields of glucose of around 50%. These yields are approaching the theoretical limits for such continuous reactor systems.

In April 2004, Iogen Corporation, a Canadian biotechnology firm, became the first business to commercially sell cellulosic ethanol, though in very small quantities. The primary consumer thus far has been the Canadian government, which, along with the United States government (particularly the Department of Energy's National Renewable Energy Laboratory), has invested millions of dollars into assisting the commercialization of cellulosic ethanol.

Another company which appears to be nearing commercialization of cellulosic ethanol is Spain's Abengoa Bioenergy ^[2]. Abengoa has and continues to invest heavily in the necessary technology for bringing cellulosic ethanol to market. Using process and pre-treatment technology from SunOpta Inc.(NASDAQ: STKL), Abengoa is building a 5 million gallon cellulosic ethanol facility in Spain and has recently entered into a strategic research and development agreement with Dyadic International, Inc. (AMEX: DIL), to create a new and better enzyme mixtures which may be used to improve both the efficiencies and cost structure of producing cellulosic ethanol.

On December 21, 2006, SunOpta Inc. announced a Joint Venture with GreenField Ethanol, Canada's largest ethanol producer. The joint venture will build a series of large-scale plants that will make ethanol from wood chips, with SunOpta Inc. and GreenField each taking 50% ownership. The first of these plants will be 10 million gallons per year, which appears to be the first true "commercial scale" cellulosic ethanol plant in the world. Under 1 million gallons per year (MMgy) is considered "Pilot Scale", greater than 1 MMgy but less than 10 MMgy is defined as "commercial demonstration", while a plant that produces 10 MMgy per year or greater is true "commercial scale". Despite the multiple commercial demonstration cellulosic ethanol plants SunOpta has been involved with, media reports continue to state that cellulosic ethanol is an unproven, "experimental" technology. The 10 MMgy SunOpta/GreenField cellulosic ethanol plant is intended to demonstrate that large-scale cellulosic ethanol is commercially viable immediately.

President Bush, in his State of the Union address delivered January 31, 2006, proposed to expand the use of cellulosic ethanol. In his State of the Union Address on January 23, 2007, President Bush announced a proposed mandate for 35 billion gallons of ethanol by 2017. It is widely recognized that the maximum production of ethanol from corn starch is 15 billion gallons per year, implying a mandated production of some 20 billion gallons per year of cellulosic ethanol by 2017. Bush's plan includes $2 billion funding for cellulosic ethanol plants, with an additional $1.6 billion announced by the USDA on January 27, 2007.

In March 2007, the US government awarded $385 million in grants aimed at jumpstarting ethanol production from nontraditional sources like wood chips, switchgrass and citrus peels. Half of the six projects chosen will use thermochemical methods and half will use cellulosic ethanol methods.

The American company Range Fuels announced in July 2007 that it was awarded a construction permit from the state of Georgia to build the first commercial-scale 100-million-gallon-per-year cellulosic ethanol plant in the United States. Construction began in November, 2007.

All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.)
Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a U.S. registered 501(c)(3) tax-deductible nonprofit charity.