In order to study the influence of self-desulfurization effect on calculation parameters of limestone desulfurization in coal-fired circulating fluidized bed(CFB) boiler

an experimental study was carried out on 1 MW CFB test device. The results show that

the self-desulfurization efficiency of the two tested coals was 73.5% and 57.3%

respectively. The difference of self-desulfurization efficiency between the two coals was mainly related to the combustible sulfur content

CaO and other alkali metal oxides content in the coal and boiler operation parameters. The mole ratio of calcium to sulfur calculated by the sulfur content modified according to the SO_2 emission was 3.78 times of that by the as received basis total sulfur content. With the increase of limestone added

the deviation of desulfurization efficiency gradually reduced from 20.06% to 10.65%. The desulfurization heat losses calculated by the sulfur content of fuel corrected by SO_2 emission were all positive

while that by the as received basis total sulfur content were all negative. The reason was that the latter included the heat released from the sulfur fixation reaction of self-desulfurization of in-furnace coal into the heat released from limestone desulfurization reaction. Due to the influence of coal-fired self-desulfurization effect on CFB boiler

the calculation error of desulfurization heat loss based on as received basis total sulfur content is large. It is more realistic to calculate the desulfurization heat loss according to the actual emission value of SO_2.