Energy from Papermaking Waste Can Heat Homes with Less Pollution, According to New Study

Graduate students at Penn State University carried out research that has resulted in a promising energy source. Black liquor, a waste product from paper making, can be combined with coal to produce a fuel that is already being used to heat homes and fuel vehicles in China. Black liquor consists of lignin from wood, chemicals used in paper making, and water. Standard practices are to burn the waste in a recovery boiler to reclaim the inorganic materials. However, it has higher value when converted to a synthesis gas to be used in creating other fuels. One of these possible fuels is dimethyl ether, or DME.

Andre Boehman, professor of fuel science at Penn State, reported the results of the team's research at a meeting of the American chemical Society on August 20^th. Boehman says DME cold be used as fuel for cooking in the U.S. and Japan. He also states in the Penn State press release, "DME has recently grown in both production and use and is replacing coal for home heating and cooking in China." The graduate students participating in the research were Nicole Reed, Gregory K. Lilik, Jamie Clark , Qiziu Li and Chunmei Wang.

Japan and China have some diesel trucks and buses running on the fuel. Volvo has an experimental truck that runs on DME, and other automotive companies are testing vehicles. Penn state had the first transit vehicle use of DME in 2002, when a staff shuttle was modified to carry staff and faculty around campus.

The students at Penn State University found that gas and diesel fuel still has the lowest cost to produce. Yet DME does not lag far behind in efficiency and its use is increasing globally. While large-scale production is required to make the process efficient and economical, paper mills could co-process coal and black liquor to expand their fuel processing ability.

One of the advantages of using black liquor and coal to produce DME is that the process results in less carbon dioxide released into the atmosphere than when only coal is used for production. Some of the carbon resulting from the black liquor-coal process remains in solid form and does not contribute to global warming.