Enerkem syngas-to-ethanol plant starts up

By Anna Austin | February 04, 2009
Quebec-based Enerkem Inc. began the start-up phase at its commercial-scale synthesis-gas-to-ethanol/methanol plant in Westbury, Quebec, in January after a 14-month construction period.

The company has operated a pilot plant in Sherbrooke, Quebec, since 2003. Enerkem President and Chief Executive Officer Vincent Chornet told EPM that he expects the commercial-scale facility to become fully operational within a few months after the alcohol modules are bolted to the syngas island.

Enerkem received financial support for the construction of the plant from Sustainable Development Technology Canada, and the Quebec Natural Resources and Wildlife Ministry.

The company's sequential gas-conditioning and catalysis technology allows for the processing of certain types of demolition wood, such as decommissioned power poles and creosote-treated wood that most companies can't process due to air permit limitations. Appropriately, the 1.3 MMgy facility is collocated with a saw mill and will utilize waste wood materials to produce 365 liters (95 gallons) of ethanol per ton. It's operated by a team of 13 people.

Besides treated wood waste, the plant will also be capable of processing other sorted municipal solid waste. "Forestry biomass is like butter for us, although the plant is designed to be flexible," Chornet said.

After the wood chips or other wastes are dried, sorted and shredded, they are stored in a container connected to the gasifier by a front-end feeding system. Slurries or liquids may also be fed into the gasifier through injectors. The carbonaceous materials are converted into a syngas, consisting mostly of carbon monoxide and hydrogen, through a chemical gasification process.

The gasification process uses air as a partial oxidation agent or oxygen-enriched air, which includes steam at a specific partial pressure. The gasifier operates at low severities, temperatures of approximately 700 degrees Celsius (1,292 degrees Fahrenheit) and below 10 units of atmospheric pressure. During the gasification process, part of the creosote is broken down, forming a portion of the syngas.

Other traces of impurities are captured as residues in the form of a neutralized ash, or through a wastewater treatment system for effective disposal through the syngas cleaning system. At this stage, the gas is cleaned and conditioned for use with existing catalysts, which is accomplished through a sequential conditioning system that includes the cyclonic removal of inerts, secondary carbon and tar conversion, heat recovery units, and the reinjection of tar and fines into the reactor. The gas that is produced at the end of the cleaning process is ready for conversion into liquid fuel and end products.

The ethanol produced at Enerkem's facility will be sold within Canada to refineries. Chornet said the company is currently in talks with refineries in the greater Montreal area.

Notably, Enerkem has partnered with top Canadian ethanol producer GreenField Ethanol and the city of Edmonton, Alberta, to construct another cellulosic ethanol/methanol plant, which will use municipal solid waste as a feedstock. Chornet said the Alberta project is on schedule and should be entering the construction phase in 2009.