Thermal conversion of biomass and municipal solid wastes: Understanding the effect of organic and inorganic components on process performance

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Municipal solid waste (MSW) in landfills causes serious problems of GHG emissions. Canada produces one of the highest MSW per year (777kg per capita) requiring a proper management and/or large area for landfills. Other than MSW, the agricultural residues, and wastes from forest can add to the greenhouse gas (GHG) emissions if not utilized. Therefore, thermal conversion of MSW to power or chemicals is a very promising option to avoid the landfill and mitigating GHG emissions. MSW is the most complex in nature, firstly, because it consists of food wastes, garden wastes, plastics, paper, wastes from construction and demolition - each having different characteristics and, secondly because inorganic matter in these components interact with each other causing slagging/fouling/ sintering problems. The operational issues very much depend on the technology to be used. The most common technology used is fluidized bed gasification. However, there are three main problem in fluidized bed gasification (800-1000C): elutriation of fine fuel particles causing lower efficiency, agglomeration and sintering of ash and bed material and tar formation. The advantage is the retention of alkalis and S in bed material and ash. However, at high temperature entrained flow gasifier (1200-1400C) can overcome the issue of tar and bed agglomeration. In this proposal, the methodology will be to study each major individual component of MSW including garden clipping, agricultural residues tyres etc. in fluidized bed reactor (FBR) and entrained flow reactor (EFR) for the following three aspects: i)The impact feed quality and operating conditions on conversion efficiency combustion or gasification ii)Operational issues related to the inorganic matter - fouling, slagging and ash deposition. The operational problems such as agglomeration, deposition, and corrosion problems. iii)Environmental performance issues - emission of fine particulate matter, trace and toxic elements. The investigations of this aspect are scarce in the available literature. The synergy in the processing of these blends of different components - MSW, will be investigated for these aspects in terms of pyrolysis, gasification and interaction of ash components in reducing tar formation, reducing slagging/ fouling and reducing emission of fine particulate matter end trace/toxic elements. The main objective of the research is to develop a methodology for a consistent evaluation of MSW gasification process high temperature gasification processes. The short term objective, is to understand the pyrolysis behavior of individual component and the thermal conversion of char under different conditions using thermogravimetric analysis, a bench scale fluidized bed (FBR) and drop tube furnace (EFR), The knowledge generated in this program will provide more efficient thermal conversion of MSW and different types of biomass wastes and mitigation of GHG emissions in Canada.