Issues encountered during the first startup of a heating furnace

During the first startup of the new furnace, a drying process takes place, during which the moisture in the furnace walls and lining is vaporized. Recommendation: Once the main burner of the heating furnace is ignited, switch the furnace to forced ventilation, that is, activate the waste heat recovery system. This will prevent dew point corrosion in the waste heat recovery system as well as the peeling off of the lining.

We first use natural ventilation and flue exhaust, turn on the permanent lights and burners, and once the furnace temperature reaches the required level, we then activate forced ventilation.

Starting forced ventilation makes it difficult to ignite the fire; we always light it first and then start the fan, keeping the flow rate low at first. Because it is still relatively humid when the furnace is first lit, it is prone to flashback or going out.

Ignition steps: (1) Fully open the natural ventilation doors, and slightly open the secondary air valves for each burner. (2) Adjust the flue dampers and air valves to keep the furnace negative pressure at 20–50 Pa. (3) Purge the furnace with fire-fighting steam; stop the purging 5 minutes after steam is visible in the chimney. (4) Sample the gas in the furnace for analysis; a combustible gas content of <0.5% is considered acceptable ； The convection chamber needs to be steamed. (5) Adjust the blind flange of the flame-lit perpetual light line; note: adjust it as the flame is lit. (6) Light the ignition rod or gas igniter and insert it into the corresponding ignition hole so that its flame reaches the top of the permanent light; then slowly open the hand valve to ignite the permanent light. (7) As needed, turn on the pilot lights or main burners in sequence according to the ignition order; adjust the burner control valves to keep the flames short and even; adjust the flue dampers and air valves so that the flames appear as a bright blue color. (8) Change to forced ventilation and integrate the flue gas into the air preheating system (see details on the operation of the air preheating system). (9) Precautions for ignition: A. Before igniting the heating furnace, it is necessary to adjust the flow path of the furnace tubes so that a medium flows through them in both the radiation section and the convection section, thereby preventing the tubes from being damaged. B. When lighting, one should turn sideways and face the upwind direction, rather than facing the burner directly, to prevent backfire from causing injury. C. When lighting the first permanent light, if ignition does not occur after the fuel gas manual valve has been open for 10 seconds, it is considered an ignition failure; the furnace must be purged again, and ignition can be attempted once the sampled explosion gases are found to be satisfactory. D. During the ignition process, the heating rate of the furnace chamber must be controlled at <100°C/h. E. During low-temperature control, the flue dampers and secondary air valves should be set at a lower opening to prevent the fire from going out.

It depends on the type of heating furnace; for example, forced ventilation must be established in the converter of a hydrogen production plant.

Forced ventilation, with excessive air pressure, can easily blow out the flames. . . Generally, it is necessary to ensure positive pressure in the furnace before ignition. . . . Light the fire first, then turn on the fan for positive pressure ventilation; subsequently, according to the process requirements, adjust the fuel supply as well as the flue dampers and air vents in order to keep the fire burning vigorously. . . ^_^. . . :lol Last edited by wangsc on 2009-3-4 14:09 ]

For ignition, natural ventilation and using the chimney is preferable; forced ventilation should be activated only after all fire pits are burning properly.

Once the main fire is lit, turn on the blower and exhaust fan; the oxygen level and negative pressure in the furnace can be adjusted using butterfly valves!

We have always used forced ventilation when starting the fire, and it works well; as long as the furnace can be ignited, it’s suitable for our setup

For delayed coking heaters: 1. When lighting the furnace for the first time, it is necessary to take into account the process of drying out the furnace; the surface moisture on the furnace walls and chimney linings evaporates slowly. Therefore, natural ventilation should be used for lighting the furnace, as this makes it easier to start the furnace and allows for better temperature control. Once the furnace temperature reaches 250–300°C, the fan should be started, and the heater should switch to forced ventilation； 2. If it’s not for furnace drying, natural ventilation should be used for the first ignition as well; forced ventilation makes it difficult to ignite the furnace, increases the risk of it going out, and can lead to the burner losing contact with the fuel, resulting in secondary combustion and compromising safety. When the furnace temperature reaches 250–300°C, start the fan to switch the furnace to forced ventilation.

It’s better to start with natural ventilation; once the exhaust temperature reaches around 189 degrees, then turn on the fans.