In general, during ignition, the primary air for fluidization remains in critical state, the purpose is to increase the bed temperature as far as possible to reduce heat loss. But when the oil gun is used, special attention shall be paid to the change of the air volume for fluidization, when the oil gun is  ignited, the air inside the air duct will be suddenly heated and expands, so the resistance to the primary air chamber increases,  total volume of the primary air for fluidization decreases. When the oil gun operating is stopped, the opposite phenomenon will appear, so the primary air fan inlet guide vane opening shall be corresponding increased or decreased in order to ensure that the primary air for fluidization is not less than the critical value and the bad materials shall be good fluidization status.      (lsh)