Gas nozzle clogging issue when heating coke oven gas
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When using coke oven gas for heating, the hydrocarbons present in high concentrations in coke oven gas decompose at high temperatures to produce free carbon, which can easily clog the gas nozzles and increase the resistance in the combustion system. I wonder if this problem occurs in everyone’s coke ovens; how can it be resolved? I hope everyone will engage in active discussions; high scores will be given as incentives~
Personal opinion: When it’s blocked, just introduce some oxygen to oxidize the carbon inside!
By what method should it be introduced? Is compressed air supplied from the brick gas duct?
Raising the preheating temperature is very effective; increasing the pressure in the branch pipes also reduces clogging of the gas nozzles.
Under normal circumstances, after the heating mode is switched for coke oven gas, negative pressure in the combustion system is used to draw air into the gas pipeline through the carbon removal holes in order to burn off the graphite. I’m not sure if that’s correct Everyone is talking about it~
When the gas inlet at the bottom of the vertical flue (or the upper and lower nozzles) is blocked by graphite, it can be cleared using a steel rod; in cases of more severe blockages, the thread plug at the bottom of the vertical pipe can be removed first, and after one or two exchanges, the blockage can be cleared. When the brick gas ducts become blocked due to swelling caused by the clay mixture and bricks, oxygen can be blown in using an iron pipe to melt the blockages. However, it is necessary to seal them tightly before blowing in oxygen, in order to prevent gas from leaking out and mixing with oxygen, which could cause a fire or explosion.
Open the lower thread plug of the standpipe – how should it be burned? Is it driven by compressed air or automatically drawn in by the negative pressure of the combustion system? It is also stated in books that coke oven gas exchange valves are equipped with carbon removal holes; when no coke oven gas is supplied, air can be introduced through these holes. I would like to ask how to do this Automatically drawn in by the negative pressure of the combustion system? Are the carbon removal pores usually closed as well, and aren’t they needed at all?
We use prying tools and compressed air for cleaning.
Additionally, I have another suggestion for the original poster: replacing the gas nozzle with a small orifice plate will also yield good results. We once had two identical coke ovens; the one equipped with gas nozzles required daily cleaning, and the nozzles still got clogged frequently. However, with the identical coke oven equipped with orifice plates and under the same heating parameters, cleaning was sufficient every three days.
I would like to ask if your coke oven gas exchange valves have carbon removal holes? What’s the usual state? Turn it off since it’s not being used?
Replace the orifice plate and perform a compressed air purge
The exchange plug is a tee with carbon removal holes on it; these holes are open during the downward airflow to allow air to be drawn in. Generally, the brick gas ducts and lamp holder bricks don’t get clogged either; if they do, a steel wire can be used to clear them. If clogging occurs frequently, it might be due to leaks in the brick gas ducts, in which case grouting can be applied as a solution.
Is the air upstairs automatically drawn in through negative pressure from the combustion system?
Isn’t it a bit dangerous to draw in air using negative pressure? If there is an abnormal pressure in the combustion system, after the replacement, exhaust gases enter the gas pipeline and mix with the remaining gas, causing an explosion.
We often encounter this situation as well; usually, we simply unscrew the plug at the bottom of the vertical pipe, and after 24 hours, the graphite disappears on its own. We can also use a long iron rod to reach down from the bottom of the vertical pipe in order to clean it.
Every 24 hours, how should it be heated during that time? ?
What is said on the fifth floor is that, under normal exchange conditions, the air from the carbon removal hole of the valve is sufficient to eliminate any residual gas； If the blockage is caused by free carbon generated during pyrolysis, the likely reasons are an excessively long coking time, a low gas flow rate, and a high furnace temperature ； It could also be due to the accumulation and blockage of impurities resulting from poor gas purification. If there is a blockage at the burner, it can be cleared using compressed air; removing it through combustion is also an option. However, it is best to analyze the root cause and address it accordingly.
Without heating for 24 hours, it does affect the heating of this particular eye, but the impact on the entire row is minimal.
May I ask that when using coke oven gas for heating, with the carbon removal holes remaining open at all times, could there be a popping sound during the exchange process due to exhaust gas entering the gas pipeline and mixing with the remaining gas? Also, when the pressure at the bottom of the vertical flue is high, could exhaust gas leak out through the carbon removal holes? Last edited by Lawlessness on 2009-4-13 13:50]
Generally, the inside of a combustion system is under negative pressure, so there should be no exhaust gas leakage, right? As for whether there is a roaring sound or not, I’m not sure; I hope those who use coke oven gas for heating can discuss this together.
I’ve read that if the seal of the switching valve is not tight during the switching process, it may lead to a leak of coke oven gas, resulting in an explosion. But the phenomenon you mentioned isn’t very clear.