Coskata Aims for $1 a Gallon Et-OH Using Plasma

Coskata's gasification process uses a plasma "torch" to gasify biomass to syngas. The syngas is then converted to ethanol using proprietary micro-organisms.

Coskata leverages proprietary microorganisms and efficient bioreactor designs in a three-step conversion process that can turn virtually any carbon-based feedstock into ethanol, from anywhere in the world. The three steps are:

1. Gasification. Carbon-based feedstock is converted into syngas using well-established gasification technologies. In the Madison demo plant, plasma torches will super heat feedstock to 1,600°F (871°C), which creates a synthesis gas consisting of carbon dioxide and hydrogen.

At its commercial scale plants, Coskata intends to use WPC Marc-11 plasma torches, which have been proven in metallurgical and waste-to-energy commercial applications throughout the world. The Marc-11 torches have more than 500,000 hours of operation in industrial settings, including a GM foundry in Defiance, Ohio.

A smaller version, the Marc-3, will be used in Coskata’s Madison facility. A WPC Marc-3 has been used in Japan to gasify municipal solid waste for more than five years.

2. Fermentation. The syngas is cooled to about 100°F (38°C). Coskata’s proprietary microorganisms convert the cooled syngas into ethanol by consuming the carbon monoxide (CO) and hydrogen (H2) in the gas stream.


3. Separation. Pervaporation technology separates and recovers the ethanol.

Plasma is the term given to a gas that has become ionized—i.e., one where the atoms of the gas have lost one or more electrons and have become electrically charged. Man-made plasma is formed by passing an electrical discharge though a gas such as air or oxygen. The interaction of the electric discharge and the process gas causes the temperature of the gas to increase significantly often exceeding 5,500°C (10,000°F).

WPC’s plasma torches can be fed with process gases of widely varying chemical composition including air, oxygen, nitrogen, argon and others. WPC’s plasma technology can increase the energy of the process gas to between two to ten times higher than conventional combustion. __GCC

A wide variety of gasification approaches are being taken by various biomass to liquid fuels (BTL) processors. As they compete in the marketplace, we will eventually discover how cheaply liquid biofuels can be made from cellulose and other non-food feedstocks.