Some people think that the more fuel you add, the more steam you produce.But if too much fuel enters the furnace, the effect will be counterproductive.When the amount of air is certain and the amount of fuel is too much, the furnace will produce a large number of incomplete combustion, resulting in a waste of energy.
This is the main reason why hearth fires are so often seen to dim and faint, and chimneys to emit black smoke.In serious cases, pulverized coal furnace will appear fire extinguishing, oil furnace will appear secondary combustion, tube explosion until the furnace stop.
Therefore, the ratio of fuel and air volume should be adjusted properly, usually by looking at the fire, smoke, oxygen meter instructions to determine.When the flame in the furnace is bright yellow, the chimney emits light gray smoke, and the steam pressure is stable, it indicates that the ratio of air coal is appropriate and the combustion condition is good.
Myth 2: the more fire, the better
Dial fire is a common manual operation method of industrial boilers.By dialing the fire, it can eliminate the crater, reduce the ignition and make the furnace fire bed level off, and burn evenly and strongly.
But too much fire, but will reduce the comprehensive thermal efficiency;This is because when dialing the fire, a large number of cold air into the furnace, reduce the average temperature of the furnace cross section flame.
At the same time, the heat loss of exhaust smoke increases, the number of black smoke emitted from chimneys increases, and the environment is polluted.In addition, when dialing the fire, the staff is also prone to flame radiation and scald, and the refractory layer of the furnace is also easy to be damaged by the dialing tool, which aggravates the maintenance workload of the furnace.Therefore, according to the need to dial the fire, dial as little as possible appropriate.
Misunderstanding 3: the bigger the negative pressure in the furnace, the better
The negative pressure in the furnace is one of the important parameters to reflect whether the combustion condition is normal or not.The negative pressure of boiler furnace operation should be maintained between 10 ~ 20Pa. Excessive negative pressure will lead to:
(1) the air leakage in the furnace increases, and the heat loss of exhaust smoke increases;
(2) the fan power consumption is increased;
③ The wear of fly ash on the heating surface along the path is aggravated;
(4) reduce the combustion heat efficiency of the furnace.
Most gas-fired boilers are designed to operate under micro positive pressure to increase the combustion rate.In the operation, the negative pressure in the furnace becomes positive, and it is difficult to maintain the negative pressure in the furnace even if the air diversion is increased, then it indicates the failure of the air diversion system or the leakage of the water wall tube and superheater in the furnace.When a furnace extinguishes a fire, the first reflection is that the air pressure gauge in the furnace swings violently and throws its head in a negative direction.
Therefore, the negative pressure in the furnace must be operated according to the provisions, otherwise the cause should be identified.