Biofuels from pulp & paper by-products economically feasible, concludes Swedish study
27 April 2004
A new Swedish study concluded that renewable transportation fuels can be produced from biomass via black liquor gasification at a cost which is competitive with fossil-based gasoline and diesel.
In a recently finished EU project called BLGMF (Black Liquor Gasification with Motor Fuels production), a group of companies—Nykomb Synergetics, Volvo Bus Corporation, OK-Q8, Methanex, Chemrec, STFI and Ecotraffic—have investigated the possibilities to produce green transport fuels from biomass via gasification of “black liquor”, a by-product in the pulp & paper industry.
The group has made a technical and economical comparison of the new technology with today’s conventional methods of black liquor processing. The objective has been to maximize, in an environmentally friendly way, the chemical and energy recovery cycle efficiency in a pulp & paper mill, and at the same time produce transport fuels, such as bio-methanol or dimethyl ether (DME) from added biomass via black liquor gasification. The gasification technology (developed by Chemrec) results in biomass to bio-methanol conversion efficiency as high as 66%.
Due to the high process efficiency, a modern Swedish pulp & paper mill could produce bio-methanol at a cost which could compete with gasoline, concluded the study. This means that the cost of green transport fuels at the pump would be competitive with gasoline, including distribution cost and Swedish CO2 tax, but excluding other taxes.
The raw “black liquor” material is generated during washing of the pulp. It contains approximately half of the organic material that was originally present in the wood, and almost all of the inorganic chemicals that were used for delignification. In the conventional pulp & paper process, the black liquor is evaporated and burned in a recovery boiler, often referred to as the Tomlinson boiler.
The total production potential in Sweden has been estimated at about 4 million tons/year of bio-methanol, which could replace almost 30% of all consumed transport fuel. The combined effect would be a carbon dioxide reduction of almost 6 million tons/year and a lowering of Swedish carbon dioxide emissions by 12%. The Swedish commitment towards the Kyoto protocol is a reduction by 4% of CO2 equivalents from 1990 year’s level. In USA and Canada the production potential of bio-methanol is 28 million tons and 7 million tons, respectively.
The gasification technology will be verified in a 20 ton dry solids per day development plant at the Kappa Kraft liner pulp mill in Piteå, Sweden, which will start production by the end of 2004. A 20 times larger demonstration plant is planned within the next few years.