Does the exhaust incinerator have pressure limits? Is positive pressure better or negative pressure better?

This post was last edited by adsl121 on 2010-3-17 23:07. Incinerators usually operate under negative pressure. However, some units are equipped with flue dampers, which can be used to adjust the operation to positive pressure. Especially when the incinerator shuts down, if it is under negative pressure, ignition becomes difficult; however, if the incinerator is made to be under positive pressure using baffles, ignition becomes much easier.

The flue gas furnace is usually kept at positive pressure. Our unit is equipped with a ventilation baffle at the rear of the flue gas furnace, and a DN700 butterfly valve is located behind the flue gas heater. When the flue gas furnace stops operating, negative pressure builds up, which makes it difficult to ignite the furnace. Ignition is controlled through the ventilation baffle and the DN700 butterfly valve, but this process takes time and the valves are not very flexible in operation. During ignition, a low air flow can be controlled to keep the negative pressure low, making ignition easier.

Due to the suction force of the chimney, the incinerator operates under negative pressure; I think it’s relatively easy to ignite it as long as the negative pressure isn’t too high!

During normal operation, the flue draft creates a negative pressure in the incinerator, ensuring smooth flow in the process gas system； When lighting the furnace, be careful to reduce the negative pressure to prevent it from being extinguished right after ignition

The exhaust gas incinerator is normally designed as a negative-pressure furnace, but it is difficult to ignite such a furnace at startup. Therefore, initially a slight positive pressure is adopted in the standard configuration, and during normal production no changes are made, keeping it at a slight positive pressure. Active participation

After the shutdown of the valve behind the furnace, it gets stuck at a wide opening, making it difficult to adjust that opening. Would increasing the air supply in order to reduce the negative pressure help with ignition?

During ignition, the system is maintained at a slight positive pressure by controlling the air flow rate as well as the rear baffles and butterfly valves, which facilitates the process of lighting the furnace. During normal operation, it can be adjusted to a slight negative pressure, which facilitates the protection of equipment and the extraction of smoke

Whether an incinerator is designed to operate under positive or negative pressure depends on the type of waste being burned and the conditions of the processes prior to combustion; if the waste in question is listed as a hazardous substance, it is better to design the incinerator to operate under negative pressure, as this is required by relevant regulations. If it is combustion exhaust gas and the pressure of these emissions is relatively high, then, from the perspective of operating costs, it is possible to design the incinerator to operate under positive pressure.

The ignition of the incinerator, re-ignition after it has been turned off, as well as its normal operation, have nothing to do with whether the incinerator is under positive or negative pressure! This is a matter related to the design of the burner and the operating conditions of the furnace. We can discuss this further if there’s a chance.

This post was last edited by adsl121 on 2010-3-30 00:41. Negative pressure and the difficulty of ignition shouldn’t be related, right? There is no need to deliberately strive for the incinerator to operate under positive or negative pressure; the usual outlets for an incinerator are waste heat boilers and chimneys. Therefore, the pressure drop in the waste heat boiler and the suction force of the chimney determine the pressure within the incinerator. The suction force of the chimney is related to its height and the temperature of the exhaust gases, while the exhaust gas temperature is connected to the measures taken to prevent corrosion in the chimney as well as the energy consumption associated with the operation of the equipment. The height of the chimney is determined by environmental emission standards. So in fact, it is the chimney that determines the pressure of the incinerator. Of course, the lower the pressure, or the greater the negative pressure, the lower the outlet pressure of the blower in the exhaust gas incinerator can be. This also helps to reduce the pressure throughout the entire system, thereby lowering the outlet pressure of the blower in the acidic gas combustion furnace as well. This is highly beneficial for energy savings in the facility. In short, if conditions permit, the absolute pressure of the incinerator should be as low as possible; there is no minimum – only lower values:lol.