Cellulosic developers make case for integrated ethanol production

By Kris Bevill | June 05, 2012

Corn ethanol and cellulosic ethanol have previously been viewed as entirely separate products which will be manufactured by two unique types of producers, but the concept of integrating cellulosic production into corn ethanol plants is gaining popularity as producers begin to consider the benefits of integrated production models. At the 28th annual International Fuel Ethanol Workshop & Expo held June 4-7 in Minneapolis, several cellulosic technology developers said they are ready and willing to team up with conventional ethanol plants and presented tempting reasons why corn ethanol producers should consider branching out.

Dwight Anderson, bioconversion manager Catchlight Energy LLC, said co-producing cellulosic ethanol would offer corn ethanol producers the ability to hedge against low ethanol prices and take advantage of the growing demand for cellulosic biofuels, so long as the renewable fuel standard (RFS) continues to be enforced. Also, while corn prices have shot up in recent years, the cost of some potential cellulosic feedstocks, namely wood, have remained steady. Catchlight, a joint venture between Chevron Corp. and integrated forest products firm Weyerhaeuser Co., was formed to commercialize cellulosic fuels produced and has worked extensively with soft woods but has tested other feedstocks as well. Anderson said Catchlight is interested in partnering corn ethanol producers and can supply them with pre-treated cellulosic feedstocks, negating the need for corn producers to add pre-treatment capabilities at the existing facility.

The pretreatment stage is key to any cellulosic ethanol process, said Barry Wortzman, vice president of business development at Greenfield Ethanol Inc., and his company believes it has developed equipment that will be a game-changer in that area. At its core is a modified twin screw extruder which Wortzman said can be used with various feedstocks, and is less than complex, more efficient and less costly than other extruders. “The result? We expect to achieve the best-in-class yield from both C5 and C6 sugars at a cost of about $2 a gallon,” he said. Greenfield’s strategy to commercialize cellulosic ethanol calls for the equipment to be integrated at one of its existing ethanol facilities by the end of the year, where it will be validated before the company begins engineering its first bolt-on cellulosic facility. Wortzman said Greenfield expects to begin building its first bolt-on plant in 2014.

Paul Kamp, who provides North America sales and project support for Denmark-based Inbicon Biomass Refinery, said corn ethanol producers should consider integrating cellulosic production into their facilities because they can share feedstock suppliers, heat and power sources and because it offers a way for corn ethanol producers to supply the cellulosic gallons demanded by the RFS, however he stressed the need for policy certainty related to cellulosic production. Inbicon’s strategy involves partnering with corn ethanol producers to co-locate 20 MMgy cellulosic facilities, a model which Kamp said could transform the ethanol industry if policymakers commit to cellulosic biofuels.