NEW SOLID FUELS FROM COAL AND BIOMASS WASTE

Farzan, Hamid

National Energy Technology Laboratory (U.S.)

关键词: Natural Gas;    Construction Industry;    Biomass;    Greenhouse Effect;    01 Coal, Lignite, And Peat;   

DOI  :  10.2172/789505
RP-ID  :  AC26-99FT40158--01
RP-ID  :  AC26-99FT40158
RP-ID  :  789505

美国|英语

来源: UNT Digital Library

【 摘 要 】

Under DOE sponsorship, McDermott Technology, Inc. (MTI), Babcock and Wilcox Company (B and W), and Minergy Corporation developed and evaluated a sludge derived fuel (SDF) made from sewage sludge. Our approach is to dry and agglomerate the sludge, combine it with a fluxing agent, if necessary, and co-fire the resulting fuel with coal in a cyclone boiler to recover the energy and to vitrify mineral matter into a non-leachable product. This product can then be used in the construction industry. A literature search showed that there is significant variability of the sludge fuel properties from a given wastewater plant (seasonal and/or day-to-day changes) or from different wastewater plants. A large sewage sludge sample (30 tons) from a municipal wastewater treatment facility was collected, dried, pelletized and successfully co-fired with coal in a cyclone-equipped pilot. Several sludge particle size distributions were tested. Finer sludge particle size distributions, similar to the standard B and W size distribution for sub-bituminous coal, showed the best combustion and slagging performance. Up to 74.6% and 78.9% sludge was successfully co-fired with pulverized coal and with natural gas, respectively. An economic evaluation on a 25-MW power plant showed the viability of co-firing the optimum SDF in a power generation application. The return on equity was 22 to 31%, adequate to attract investors and allow a full-scale project to proceed. Additional market research and engineering will be required to verify the economic assumptions. Areas to focus on are: plant detail design and detail capital cost estimates, market research into possible project locations, sludge availability at the proposed project locations, market research into electric energy sales and renewable energy sales opportunities at the proposed project location. As a result of this program, wastes that are currently not being used and considered an environmental problem will be processed into a renewable fuel. These fuels will be converted to energy while reducing CO{sub 2} emissions from power generating boilers and mitigating global warming concerns. This report describes the sludge analysis, solid fuel preparation and production, combustion performance, environmental emissions and required equipment.