Desulfurization Experiments Under Fluidization Reconstruction Condition And Research On Desulfurizer Milling And Feeding System

Circulating fluidized bed combustion technology is an efficient, less pollutingclean coal technology. In the development, there are some technical problems withcirculating fluidized bed boiler: combustion efficiency lower than coal-powder boiler,high power consumption rate, severe wear etc. The fluidization reconstruction theorywhich can solve these existed problems well is brought out.The paper analyzes the energy-saving fluidized bed combustion technology basedon the fluidization reconstruction theory and current limestone milling and feedingsystem. Under low pressure drop operating condition, the influence of relevant factorson CFB boiler desulfurization efficiency is studied, by controlling the bed height?monitoring the change of bed pressure drop and so on. The results are as bellows:With the increase of bed pressure drop, the released quantity of sulfur dioxidegoes down first and up last. In the dense phase zone, with the increase of bed pressuredrop, the concentration of sulfur dioxide increases, and in the dilute phase zone, theinfluence of bed pressure drop on concentration of sulfur dioxide is not obvious.In low bed pressure drop operating condition, with the increase of the averagelimestone particle mean diameter, the concentration of sulfur dioxide goes up first andgoes down last. The desulfurization efficiency is the highest when the limestonediameter ranges from0to700?m. Compared with the way of feeding from the topof dense zone, when feeding from the bottom of dense zone, the concentration of sulfurdioxide along with the bed height is much lower. It's more suitable to be fed from thebottom of the dense zone for limestone, which can increase the desulfurizationefficiency.By analysis, the limestone particle size and the limestone feeding positon is thepotential factors which can be optimized for milling and feeding system. Based on theanalysis, some improving suggestions are brought up for the milling and feedingsystem.For the milling system, the ideal limestone particle size distribution ranges from0to2mm, and the mass of limestone which ranges from0to750?m should make upthe most. Secondly, when choosing the crusher and pulverizer, more concern should befocused on the fragmentation property of the devices. The particle size distribution of limestone should be controlled at the ideal ranges.For the feeding system, the pneumatic conveying system should be prior to beselected as the limestone feeding system. For the CFB boiler operating at the lowpressure drop condition, the feeding position should be at the bottom of dense zone,otherwise, the desulfurization efficiency will decrease when the position is at the top ofthe dense zone.