27-06-2012, 12:10 PM
Biomass Power Plants
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Biomass power plants use biomass sources to generate steam or heat.
A biomass power plant most often produces steam through combustion .
The steam can be used for industrial processes or to produce electricity.
Alternatively, the heat from combustion could be directly used in an industrial process.
Another variation is a co-fired power plant fueled by coal or natural gas
combined with a biomass source.
Biomass Power Plant
Wood waste fuel would typically be stored in an outdoor pile in quantities adequate to fuel the power plant anywhere from 60 days to several years. Agricultural waste fuel would be stored in silos. Agricultural products such as switchgrass, hybrid poplars, or cottonwood trees would be stored in barns or storage domes on site. Depending upon the type of boiler, the fuel is either transported directly to the powerhouse via a belt conveyor, or first processed in a chipper/grinder to produce a finer texture.
Municipal solid waste
is deposited into pits where cranes mix the refuse and remove any large, non-combustible items; sometimes, it is further processed to remove ferrous materials, glass, and other non-combustible materials. In a fluidized bed boiler , the fuel is suspended on high-pressure jets of air during the combustion process. This not only allows combustion at relatively low temperatures and higher efficiency, but it also decreases the production of nitrogen oxide , an air pollutant.
Combustion of the fuel produces steam in the boiler that powers a turbine/generator to generate electricity. The steam is then returned to the liquid state in a condenser by circulating cooling water around the condenser tubes containing the steam. The condensed water is then recirculated to the boiler to again be heated into steam.