Experimental Investigation on a 0.35MWth Coal-fired Horizontal Circulating Fluidized Bed Boiler

摘要

The capacities of industrial coal-fired boilers are normally less than 20-30MWe.And these coal-fired boilers of low capacity are facing the severe situation of low efficiency and heavy environmental pollution.Hence,an innovative horizontal circulating fluidized bed (HCFB) boiler was developed to enhance heat efficiency and reduce pollutant emission of industrial boilers in China. The chamber in the HCFB boiler consists of primary combustion chamber,secondary combustion chamber and burnout chamber,which were combined horizontally side by side. To verify the conception of horizontal fluidized circulation and to obtain the characteristic data,a 0.35 MWth coal-combustion HCFB boiler was designed and installed to perform some experiments of combustion and mass circulation.In the boiler there were two mass circulating paths,one is inner circulating through the inertia separator and another was external circulating through the cyclone separator. The connection bottom of the secondary chamber and the burnout chamber was designed as an inertia separator,in which separated and collected solid materials were returned to the primary combustion.In fact the secondary separator was a small cyclone separator connecting to the exit of the burnout chamber.Heat efficiency and separating efficiency of the experimental boiler were measured and analyzed.Furthermore,mass and temperature distribution along the chambers height were also investigated. The results showed that the heat efficiency of the bare boiler was 82%. The mass balance based on ash content was measured and analyzed.Separating efficiency of the inertia separator and cyclone separator was 60% and 99.9%,respectively.It showed that the two stage material separation and circulation enhanced coal combustion in the HCFB boiler and help to minimize the height of the furnace.