After pulverized limestone is sent into the furnace having chemical reaction with SO2 during burning process, then remove SO2. To keep the boiler run in a proper and economic way, the key step is to use appropriate size of limestone particle. If the limestone used is bigger or smaller than what we recommended, it may bring disadvantage impact to the circulating process. Bigger size of limestone particle may result in the increase of limestone consumption, bed temperature lower than normal requirement, boiler efficiency lower than expected and the bottom ash exceeding the designed value, etc. On the other hand, if the limestone particle is smaller than what it’s required which could not reach the expected residence time in major loop, it may result in the increasing consumption of limestone and, another harmful affection is that it adds up extra loads to the flyash system, which will lead to the difficulty of ash discharge tunnel due to the existence of unreacted limestone particle. When the limestone meets with water in the wet unload system, excessive limestone will create unnecessary quantity of heat.