Based On Air Distribution Adjustment Optimize CFB Boiler Bed Temperature Deviation

CFB boiler has been rapidly developed for its advantages of high combustion efficiency,load regulation range and environmental performance.There is bed temperature deviation along the furnace width direction in 300 MW CFB boiler(DONGFANG BOILER GROUP CO.,LTD.)during operation,and the maximun is up to 110℃.Researches have showed that bed temperature deviation may reduce the desulfurization efficiency in the furnace,change the heat flow distribution in the furnace and limit the load caPacity of the boiler.In this Paper,we carried out transformation for this 300 MW CFB boiler,which shows that the central temperature is higher than both side areas’,the maximum bed temperature deviation surPasses 110℃,and the static pressure in the central area was higher than that of both side areas and the deviation percentage of bed pressure was less than 5%.Because the air volume is in direct proportion to bed temperature,we used throttling round steel to reduce the air volume,which could decrease the middle bed temperature.When the diameter of throttling round steel increases from 0mm to 35 mm,the air volume has only decreased by 6.45%;when the diameter of throttling round steel increases from 35 mm to 50 mm,the air volume has decreased by 64%.We use throttling round steel with the diameter of 40 mm,35mm and 30 mm respectively to reform air distribution situation,the bed temperature deviation has decreased by 20℃-30℃.and the bed pressure has reduced by 30%,the modification effect is goodIn this Paper,Bed temperature deviation in a 300 MW CFB boiler,which shows that the central temperature is higher than both sides’,and the maximum bed temperature deviation surPasses 110℃.Based on the situation above,we carried out the transformation,the results show that,the static pressure in the central area was higher than that of both side areas and the deviation percentage of bed pressure was less than 5%.it is put forward that the funnel cap throttle by round steel bar on the basis of uniform air distribution in the primary air chamber,which made air distribution opposite to bed temperature deviation.Besides,we conducted Experimental Study,it was found that,with the increment of the throttle diameter,the flow rate of funnel cap decreased rapidly and the decrement becomes bigger.When the throttle diameter overPasses 35 mm,the throttle effect become better.Because the air flow is proportional to bed temperature,we proposed the theory of reverse air distribution and adpoted throttles(40mm,35 mm and 30mm)to reform air distribution situation.After transformation,then removing Part or all of original bed temperature adjustment measures,the bed temperature deviation has decreased to 20℃-30℃,and running bed pressure was reduced by about 30%.