Interlock setup for heating furnace

In current process designs, a low pressure of the pilot light triggers a shutdown of the fuel gas supply; however, a low pressure of the fuel gas only results in the shutdown of the fuel gas supply itself, without affecting the pilot light. From a safety perspective, the interlock value for the constant-light function in our plant is 0.5 kg; the normal operating pressure is 1.2–1.3 kg, while the pressure in front of the fuel gas furnace is 0.8–1.0 kg. The interlock value is set at 0.07 kg. If the pressure in the gas system is low, the heating furnace will shut down completely. And there will be no situation where a continuously burning light goes out while the fuel gas is still burning. I have been doing this for 6-7 years now, and there have been no accidents in the heating furnace area. Nor were there any issues that could affect the smooth operation of production, as mentioned to the original poster. Please remember that \"safety first\".

Well, that’s usually the case. However, some units indicate that liquid in the fuel gas or other impurities can cause blockage of the pilot light flame arrester, leading to low pressure and thereby triggering a chain reaction. I hope to get rid of this chain protection. It’s really difficult.

Haha, that’s how you think about it. First, if low pressure in the pilot light is caused by liquid in the fuel gas, leading to a chain reaction, consider this: wouldn’t it be even more dangerous if that liquid entered the furnace? Liquid in the fuel gas can cause incomplete combustion; in severe cases, it can even lead to the flame going out. When large amounts of liquid-containing gas enter the furnace, it can result in localized explosions in mild cases, or backfire in the heater in more serious cases. The solution to this is to take into account the operating temperature of the gas system. If liquid enters the gas system due to abnormal conditions, the only solution is to address the issue at its source, that is, by raising the temperature of the gas system and removing the liquid urgently. II: If impurities are present in the gas, causing blockages in the filters or flame arresters, then the pressure drop in the gas system occurs gradually. It is possible to bypass the low-pressure interlock logic of the eternal light (it must be confirmed that this is the cause). Just deal with the blocked area urgently and it’ll be fine. Just my personal opinion; feel free to criticize :)

For safety reasons, it’s better not to remove it; it will also be considered a potential hazard during safety inspections. Personally, I recommend installing an additional flame arrester; in other words, two flame arresters can be used together to form a valve assembly, with one serving as a backup for the other. The one that is in regular use will be used, and once it gets clogged, switching will be made to the alternate flame arrester, after which switching back can be done once cleaning is completed.

The heating furnace in our unit has been in operation for 3 years; all other related conditions have occurred, but the low pressure condition of the permanent light has not happened yet； Both the flame arrestors and filters are in 2 sets ； Regular switching ；

It seems that safety should come first; this chain must be continued and cannot be discontinued arbitrarily

Generally, the burner is equipped with a interlock to prevent the furnace tubes from being damaged due to the absence of medium inside them. The eternal flame burner doesn’t have a interlock, so there’s no need to replace the furnace chamber when lighting it up again, and oxygen level monitoring is also not required.