Environmental performance of the Kvaerner BFB boilers for MSW combustion - analysis of gaseous emissions and solid residues

摘要

When considering the environmental impact of all waste handing, the total emissions to air, water and land have to be considered. Reliable data on all types of emissions is therefore necessary when evaluating the environmental impact of aWaste-to-Energy plant and when comparing different combustion techniques.Kvaerner Pulping AB (formerly Kvaerner EnviroPower AB) has, due to the stringent demands on emissions performance, developed a state-of-the-art bubbling fluidized bed boiler (BFB) designed for waste fuel firing (Tellgren et al., 1995) with very lowemissions to the air. Plants with this design are currently operating in Sweden and in the USA - a 2×15 MW{sub}(th) plant at Lidkoping Energi, Sweden, and a 2×30 MW{sub}(th) plant at BCH Energy in Fayetteville, NC. The emissions to air are welldocumented through Kvaerner R&D programs and commissioning tests.A complete evaluation of the environmental performance of the Kvaerner BFB technique for MSW combustion is now possible thanks to a thorough characterization study of the solid residues from the Lidkoping plant The investigation has been carried out incooperation with the Swedish Geotechnical Institute and gives the additional necessary information on the physical and chemical characteristics and the leachability of the solid residues.This paper gives an overall mapping of the emissions performance. Data from the operating plants on solid residue characteristics and leachability, heavy metal and dioxin emissions, nitrogen oxides, carbon monoxide, acid gases, and other emissions to airare presented. Comparisons are made with legislative limits and data from the mass burning technique.It is concluded that the emissions are low compared both with data from traditional mass burn incinerators and with legislative limits in the USA and Europe. Furthermore, the bottom and cyclone ash characteristics are shown not to cause any particularproblem from an environmental point of view, and that the leachability is well below the existing legislative limits in Europe and the USA. The results show that fluidized bed combustion of municipal solid waste is a very competitive alternative to thetraditional mass burning technique in every respect.