Researchers at the University of Leeds are developing a roasting process that would transform raw biomass from a bulky , water-saturated material into an energy-rich powder that is perfect for burning in coal-fired power plants. Called torrefaction, it is a relatively low-temperature process similar to that used in roasting coffee beans. If the researchers can overcome a few stumbling blocks, the process could lead to a new burst of coal-to-biomass power plant conversions, and consequently to lower greenhouse gas emissions.

Can’t Get No Torrefaction

One of the biggest obstacles to large scale torrefaction is the tendency of powders to explode in storage, so that is one area on which the researchers are focusing close attention. Part of the goal of the research is to design new safety features that can be incorporated into power plants and other large facilities. As far as coal-to-biomass conversions go, it is possible that the cost of new equipment could be offset by the lower cost of shipping and handling torrefied biomass.  Torrefied biomass could also be burned in conjunction with coal, resulting in higher efficiency and lower emissions.

Woody Biomass for Power Plants

The Leeds researchers are also looking into the use of locally grown non-food crops that are suitable for torrefaction. So far they are focusing on willow , poplar, Miscanthus (perennial grasses), and woody waste from forestry operations. Poplar is also emerging as a liquid biofuel crop, so it is possible that torrefaction would help reduce shipping and handling costs related to liquid biofuel production as well as being used in power plants.

A Place in the Sun for Woody Biofuel Crops

Here in the U.S., woody biofuel crops may prove to be a good option for reclaiming some of the millions of acres of brownfields and abandoned industrial sites that the EPA has targeted for alternative energy production. As managed forests, woody biofuel crops could double as recreation areas and wildlife habitats. It’s  certainly a better option than undermining communities and blowing up mountains for coal.

cleantechnica.com