Technical Bulletin No. 0073: Combination Fuel Boiler Particulate Emission Control Pilot Studies (AQTB)

There is extensive use of multiple fuel-fired power boilers in the pulp and paper industry. These are commonly referred to as bark or hogged fuel boilers but in only a limited number of situations is the sole source of fuel wood-derived. Commonly a multiplicity of fuels may be burned to include a combination of two or more fossil fuels, gas and wood-derived fuel, leading to the description combination fuel-fired boilers. There is no uniform composition or ratio of fuel for combination fuel-fired boilers. On the average they may depend on as little as ten and greater than ninety percent of the heat input originating from wood-derived sources. Although most combination fuel-fired boilers are currently equipped with conventional mechanical collectors there is a widespread need to upgrade the quality of particulate emission control to meet many current regulations. This technical bulletin describes the results of pilot studies conducted on combination fuel-fired boilers to investigate the particulate collection efficiency of a multi-cyclone collector of Swedish design and recently marketed here. Also studied was the particulate collection efficiency of a venturi scrubber over a range of pressure drop.