Aerosols from circulating fluidized bed coal combustion

Characteristics of aerosols from atmospheric circulating fluidized bed combustion of low sulfur Venezuelan coal in 81 MW capacity boiler have been studied experimentally. Aerosol mass size distributions in the size range 0.01-70 μm were measured with the combination of in-situ Bemer-type low pressure impactor and cyclone sampler with estimated Stokes cut diameter of 5.4 μm to prevent overloading of upper impactor stages. Size distributions of particles collected by the cyclone were determined by Coulter and Bahco wind sieve methods. The impactor samples were also examined with scanning electron microscope, to observe the shape of the particles collected. Number size distributions in the size range 0. 01-5 μm were determined by diluting and cooling the aerosol with two stage ejector-based dilution system and measuring the number spectra with differential mobility and aerodynamic particle size analyzers. Both impactor and dilution unit samples were collected before the electrostatic precipitator at the gas temperature of about 125 C.