Enerkem Turns Waste to Energy at a Cool 700 Degrees

Enerkem is a Montreal, Canada-based company that designs, manufactures, owns and operates waste-to-biofuels plants.

Enerkem takes municipal waste and, through gasification and catalytic synthesis, converts it into advanced biofuels. The company calls its process “carbon recycling” to signal that it takes carbon that would otherwise stay trapped in the waste and converts it to useful fuels and chemicals.

Enerkem owns at least three international patent applications relating to its gasification technology, including Publication No. WO 2009/132449 (’449 Application), entitled “Production and conditioning of synthesis gas obtained from biomass.”

The ’449 Application is directed to methods of producing and treating synthesis gas, or syngas, in which a biomass-rich feedstock is passed from a conveyor belt (1) through rotary valves (2a, 2b) into a feed screw (3). (The ’449 Application contains only one figure, which is huge and incredibly detailed. I’ve reproduced a small portion of the figure below).

An oxidizing agent, such as air, is passed into the feed screw (3) from line (4). The feed screw (3) passes the biomass feedstock and the oxidizing agent into a fluidized bed section (7b) of the gasifier (7).

According to Enerkem’s web site, the technology is based on a bubbling fluidized bed reactor capable of handling fluffy material without the need to pelletize it. The gasifier can operate at low severities (i.e., temperatures of about 700º C and pressures below 10 atm), which reduces costs by allowing inexpensive construction materials to be used.

Solid residues that cannot be processed further are passed through line (8) and valves (9a, 9b) into a drum (1), and the remaining crude syngas is subjected to controlled oxidation in the freeboard section (7a) of the gasifier (7).

The crude syngas is then cleaned and conditioned in a cyclone (12), which separates out the char. The crude syngas exits the cyclone (12) through line (16) and is passed to a thermal reformer (18), where it is contacted with more gasification agents, and then sent to a heat recovery unit (20).

Ultimately, using a catalytic conversion process, the syngas is converted into fuels and chemicals, such as methanol, ethanol, synthetic diesel, synthetic gasoline, or dimethyl ether.

At least one major oil refiner likes what it sees in the Enerkem technology: the company recently announced a $60 million funding round from Valero (see Cleantechies article here).

Eric Lane is a patent attorney at Luce, Forward, Hamilton & Scripps in San Diego and the author of Green Patent Blog. Mr. Lane can be reached at elane@luce.com.