|Abengoa’s Babilafuente ethanol plant.|
Canadian company SunOpta has closed a € 4.7-million (C$ 7.1-million, US$ 5.8-million) contract to supply its patented steam explosion equipment and process technology to a subsidiary of Abengoa for the first commercial production facility in the world to convert cereal straw into ethanol.
This 5-million-liter per year (1.3-million-gallon per year) facility, scheduled to be operational in the fall of 2006, will be built in Babilafuente (Salamanca), Spain and is located adjacent to an existing 195-million-liter (52 million gallons per year) cereal grain to ethanol plant operated by Abengoa. Abengoa is the largest ethanol producer in Europe and the second largest in the world.
The combined 200-million-liter project is partly supported by € 4.5 million (US$ 5.6 million) from the EC.
SunOpta’s Staketech Division is a world leader in the preparation, pretreatment, steam explosion and extraction of value added compounds from plant biomass material.
SunOpta had entered into a partnership in May 2004 with Abengoa R&D to develop technology for the production of ethanol from lignocellulosic biomass and from starch. Abengoa is working with Novozymes on the enzymes for the process. (Earlier post.)
The awarding of this contract follows extensive development work completed at SunOpta’s pilot plant and laboratory facilities located in Norval, Ontario.
There are a number of possible pre-treatment processes that can be applied to cellulosic biomass (such as wheat straw) to prepare the fiber for enzymatic saccharification prior to fermentation and ethanol recovery:
Thermo-mechanical (grinding, milling, shearing, extruder)
Acid treatment (Dilute or concentrated H2SO4)
Alkali treatment (Sodium hydroxide, ammonia, alkaline peroxide)
Autohydrolysis (Steam pressure, steam explosion, liquid hot water)
(Iogen, the Canadian biotech company that has focused on tailoring new enzymes to increase the yield of cellulosic ethanol, and whose wheat-straw ethanol was used in the cars at the recent G8 meeting, uses a modified steam explosion technique for pre-treatment.)
In steam explosion, biomass fiber are exposed to a high pressure steam (typically 200-450 psig) for 1 to 10 minutes. The resulting product is then explosively discharged to an atmospheric pressure.
Batch steam explosion processing is almost 75-years-old. Batch processing, however, had some limitations, and was difficult to optimize. One of SunOpta’s breakthroughs was the development of a continuous steam explosion process that supports a higher processing temperature and reduces the residence time. The process greatly reduces and in many cases eliminates the chemicals associated with current industrial practice, according to the company.