The burner of the exhaust gas incinerator at Luoyang Ruichang is blocked. What causes this, and how should it be dealt with?
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This post was last edited by liaifeng on 2018-7-28 07:47. Hello, all experts and masters! Status: At the beginning of operation after the major overhaul, water was introduced into the hydrogenation catalyst. Currently, the reaction temperature is being controlled properly. A new alkali wash system has been installed downstream of the exhaust gas incinerator; however, since the inlet of this alkali wash system contains some gaseous sulfur, it condenses upon cooling and blocks the inlet, resulting in the incinerator operating at a pressure of over 16 KPa. After operating for a period of time, the volume of fuel gas supplied to the incinerator gradually decreased, and the furnace temperature dropped below 500 degrees. The valve opening and the pressure of the fuel gas were all normal, and there was no change in the amount of fuel gas flowing through the bypass as well. Currently, the pressure of the fuel gas has been increased, which has caused the temperature to rise a bit. It seems like the burner is blocked. Could everyone please help analyze what causes this blockage? Have you encountered this situation before, and how can it be resolved?
The burner uses gas or natural gas, so the possibility of the nozzle getting clogged is very low! Your current problem is the increased pressure drop caused by poor flow in the area behind the incinerator, which in turn prevents the combustion gases from flowing properly! For example: if you blow into a tube, when one end is not blocked, the airflow coming out is smooth. But when you block part of one end, the airflow coming out will feel restricted!
The clogged burner is closely related to the alkaline cleaning process you recently implemented; it’s caused by gaseous sulfur. If possible, try cleaning the burner – there are likely impurities in it
What is the quality of your air? If the temperature of the furnace is low, it is likely due to improper air supply. Check the air distribution ratio. If it is confirmed to be a sulfur blockage, the exhaust gas inlet temperature can be increased to 150°C to try and melt the sulfur. Be careful with your caustic scrubber: if it contains glass flake, keep the temperature below 180°C. However, it is still recommended to strengthen temperature control in order to ensure that sulfur droplets are separated out in the previous processing stage. If the temperature of the incinerator remains at 500°C for an extended period, blockages will become increasingly severe. Because the liquid sulfur droplets will penetrate the incinerator and enter the alkali scrubber directly.
The air supply is the air blown in by the blower; due to the high pressure in the furnace, the amount of air supplied has decreased significantly compared to before, mainly because it isn’t possible to introduce enough air. If the furnace pressure drops, air volume can be increased. The temperature of the alkali wash inlet is kept at 160 degrees, which should be acceptable. We have two sulfur recovery units here, which share one alkali solution washing system. At present, only the incinerator of one of the sulfur recovery units has difficulty in controlling its temperature, while the incinerator of the other unit can be controlled well. During the previous major repair, when it was opened, no blockage in the burner was observed.
There is a blockage in the backstream of your process; the inlet to the alkali wash system contains gaseous sulfur, which condenses upon cooling and blocks the inlet. This prevents your furnace from starting up. It is recommended that you increase the temperature of the exhaust gases. The blockage will also become more severe, and it needs to be dealt with promptly
Perhaps there are differences in the piping; did you design the alkali washing inlet at 160°C? Isn’t this temperature a bit high? So, isn’t there any sulfur in this alkali cleaning solution?
The pressure of the fuel gas in front of the exhaust furnace is around 0.2 MPa; therefore, whether the pressure of the exhaust furnace is 2 KPa or 16 KPa, it should not affect the flow rate of the fuel gas. It should have a significant impact on the air volume entering the exhaust furnace. Therefore, I believe it is correct to conclude that the exhaust furnace nozzle is blocked.
Additionally, calibrating the pressure difference is also very important for narrowing down the scope of faulty devices. It is necessary to first confirm that the pressure difference is at the exhaust furnace before proceeding with further assessment
The waste pot can also get clogged; it’s possible for the waste pot to become blocked.
Furnace blockage occurs in two scenarios: 1. Burner blockage； 2. Exhaust inlet blocked ； The situation described by the poster is clearly a clogged burner. The reason for burner clogging is the presence of heavy hydrocarbons in the fuel gas, which causes the fuel gas to heat up, condense, and coker as it exits the nozzle. It also indicates that the flow rate at the burner nozzle is relatively low.