Circulating fluidized bed combustion VS pulverized coal fired boiler
Unlike conventional PC-fired boiler, the CFBC boiler is capable of burning fuel with volatile content as low as 8 to 9 percent (e.g. anthracite coke, petroleum etc. with minimal carbon loss). Fuels with low ash-melting temperature such as wood, and bio-mass have been proved to be feedstock’s in CFBC due to the low operating temperature of 850-900°C.
CFBC boiler is not bound by the tight restrictions on ash content either. It can effectively burn fuels with ash content up to 70 %. CFBC can successfully burn agricultural wastes, urban waste, wood, bio-mass, etc which are the low melting temperature as fuels. The low furnace temperature precludes the production of “thermal NOX” which appears above a temperature of 1200 to 1300° C. Besides, in a CFBC boiler, the lower bed is operated at near sub-stoichiometric conditions to minimize the oxidation of “fuel-bound nitrogen”. The remainder of the combustion air is added higher up in the furnace to complete the combustion. With the staged-combustion about 90 percent of fuel-bound nitrogen is converted to elemental nitrogen ( N2) as main product.