|Flow diagram for Arkenol’s acid-hydrolysis process, used by BlueFire. Click to enlarge.|
BlueFire Ethanol has signed a Letter of Intent (LOI) with Petro-Diamond, Inc. for that company’s purchase of the ethanol produced from BlueFire’s first North American Biomass-to-Ethanol conversion facility located at a Southern California landfill.
Petro-Diamond, a blender of denatured ethanol into motor fuel, currently purchases more than 50,000 gallons of ethanol per day for use in its terminal facility in Long Beach, California.
The renewable multi-year agreement between BlueFire and PDI provides for floor and ceiling pricing for the ethanol based on a reasonable discount from the previous months Los Angeles average rack price and subject to escalation.
Petro-Diamond is a wholly-owned subsidiary of Mitsubishi Corporation. Established in 1983, PDI’s principal function is to expand Mitsubishi’s role in petroleum product trading in the western hemisphere, primarily in the United States.
BlueFire Ethanol was established to use the Arkenol process (earlier post) for the conversion of cellulosic waste material to ethanol.
The Arkenol process uses concentrated acid hydrolysis to process cellulosic biomass into simple sugars suitable for fermenting into ethanol. The acid hydrolysis process for alcohol production has been known for more than 100 years, but was characterized by poor yields, high wastage, and a large volume of unmarketable by-products. Arkenol developed methods for efficient acid recovery and reconcentration, and for delivering high sugar concentration at high purity.
Cleaned, dried and ground biomass is mixed with a solution of about 25-90% acid by weight to at least partially decrystallize the materials and form a gel that includes solid material and a liquid portion.
The gel is diluted to an acid concentration of from about 20–30 wt.% heated to a temperature between about 80–100° C. This partially hydrolyzes the cellulose and hemicellulose contained in the starting materials.
The liquid portion and the solid material are separated, thereby obtaining a first liquid containing sugars and acid. The separated solid material is then run through the same process again, hydrolyzing the cellulose and hemicellulose remaining in the separated solid material and forming a second solid material and a second liquid portion.
The two liquid portions are then combined, and the acids separated from the hexose (C6) and pentose (C5) sugars with an Arkenol-developed technology that uses commercially available ion exchange resins. The resulting solution has a sugar content of at least 15% by weight, and an acid content of not more than 3% by weight.
The separated sulfuric acid is recirculated and reconcentrated to the level required by the decrystallization and hydrolysis steps. The small quantity of acid left in the sugar solution is neutralized with lime to make hydrated gypsum, an insoluble precipitate which is readily separated from the sugar solution and which also has beneficial use as an agricultural soil conditioner.
BlueFire can use post-sorted municipal solid waste (MSW), rice and wheat straws, wood waste and other agricultural residues. BlueFire plans to locate their cellulose conversion facilities on landfills throughout North America, initially focusing on the California fuel market.
In it first plant, BlueFire plans to process 700 tons of green waste and other cellulosic waste material per day into 24 million gallons of fuel grade ethanol per year.