Biomass gasification: a strategy for energy recovery and disposal of industrial and municipal wastes
AbstractEnergy from biological organic waste as an aspect of sustainable waste management is probably the most contentious. Solid and liquid wastes are a rapidly growing problem worldwide. Among the clean sources of fuels for power generation, natural gas has been exploited largely due to significant availability in the specific locations. Similarly, there is also an impetus on using gas generated from industrial and municipal wastes. Many cities are confronted with the problem of how to dispose of large quantities of industrial and municipal solid waste (IMSW). Currently, landfills are the primary destination of waste. However, with landfill tipping fees rising and their proven negative environmental impacts, cleaner and less costly alternatives for industrial and municipal waste disposal should be identified and implemented. As distinct from gas generation from biological/ organic wastes the biomass by biological conversion process, which is limited to non-lignaceous matter, the thermo chemical conversion route also termed gasification can process any solid organic matter. Harnessing of energy through gasification route is not only providing to be economical but also environmentally benign.
Gasification is a process that devoltalizes solid or liquid hydrocarbons, and converts them into a producer gas. There are more than 100 waste gasification facilities operating or under construction around the world. Some plants have been operating commercially for more than five years. Gasification has several advantages over traditional combustion of MSW. It takes place in a low oxygen environment that limits the formation of dioxins and of large quantities of SOx and NOx. Furthermore, it requires just a fraction of the stoichiometric amount of oxygen necessary for combustion. As a result, the volume of process gas is low, requiring smaller and less expensive gas cleaning equipment. The lower gas volume also means a higher partial pressure of contaminants in the off-gas, which favors more complete adsorption and particulate capture according to chemical thermodynamics.
Finally, gasification generates a fuel gas that can be integrated with combined cycle turbines, reciprocating engines and, potentially, with fuel cells that convert fuel energy to electricity more than twice as efficiently as conventional steam boilers.
Keywords: industrial and municipal solid waste
Journal of Environmental Extension Vol. 5 2005: 60-64