NRRI unveils refined solid, renewable biofuel

Rolf Weberg, NRRI executive director, explains the process at a Wednesday presentation in Coleraine.

Executives from several partnership organizations were on hand Wednesday morning at UMD’s Natural Resources Research Institute Coleraine Lab as the Renewable Energy Lab was unveiled.

More than 10 years in the making, the lab currently has the ability to produce solid biofuel from wood waste on a “commercially relevant scale” of three to four tons per day. The briquette biofuel “replicates the energy output and durability of traditional coal” and can be used as an alternative to coal in electric power generation and other applications.

The briquettes currently are made through a heat treatment process known as torrefaction, which concentrates the energy content of the wood waste. Researchers describe torrefaction as a process similar to that used to roast coffee.  

“Torrefaction makes processed wood into a higher quality fuel source for combustion or gasification applications. The darkened and pelletized renewable resource is easily densified, grinds easily, repels water and does not rot, making it easier to ship and store than unprocessed wood. It basically becomes a renewable, coal-like fuel with net zero carbon emission, and reduced ash, sulfur and mercury,” NRRI explained in the organization’s Fall 2012 newsletter. 

Dr. Rolf Weberg, NRRI executive director, noted that the resulting biofuel has the advantages of being able to be stored outside and can be used in place of coal with little modifications needed.  

The lab will have further capabilities in the coming months and years. Further processing can be employed to create syn-gas or liquid fuels.

“I’m really proud to have this research lab in my district,” said Rep. Sandy Layman, R - Cohasset. “This is the first step to higher value products.”

NRRI Associate Director Don Fosnacht said that key to the research is bringing the process up to commercial scale. Commercial scale testing has already taken place through partnership with the Coalition for Sustainable Rail and others. Biofuels have been successfully used to power trains at the Milwaukee Zoo, noted Davidson Ward, president of the Coalition for Sustainable Rail. Trials have shown “serious promise.” Duane Goetsch, president of Syngas Technology, said his company is partnering in the project to allow trials to move past the traditional small laboratory setting.

“Facilities like this are rare,” he said. “To develop technology at this scale requires millions. This partnership helps clear that (financial) hurdle.”

By spring of next year, the lab facility will install a moving bed torrefaction reactor, which will greatly increase the output of briquettes. Another methodology, hydrothermal carbonization, will convert processed materials and agricultural products to an “energy mud” that can be used alone or “with other torrefied products to form solid fuels.”

The bio-energy lab is partially funded through an Xcel Energy grant. Other funding comes from the Minnesota Department of Agriculture, Minnesota Power, Heetway, K.R. Komarek, Inc. and the Consortium for Advanced Wood to Energy Solutions.