Coking problem in the fuel combustion chamber (recommended)
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What are the factors that contribute to coking in the fuel combustion chamber? How can it be avoided? This post was last edited by ybl1188 on 2008-7-2 09:07.]
Poor atomization leads to fuel droplets accumulating and coking. An excessive atomization angle or too small a combustion chamber volume results in unburned fuel accumulating and coking. An incorrect installation can also cause oil mist to accumulate and coking. For the first issue, use an atomization method and burner that are suitable for the fuel. For the second issue, adjust or replace the fuel nozzle, or modify the mixing method and conditions of the oil mist and combustion air, or replace the burner bricks (to adjust the combustion chamber size). For the third issue, ensure that the burner is concentric with the combustion chamber during installation. These are the points that come to mind for now; they are provided for reference only. This post was last edited by sminqing on 2007-12-25 at 17:33
Agree with the view from the 2nd floor; additionally, I would like to add that the air distribution and misting are not well coordinated, resulting in uneven air distribution.
Excessively high or low oil temperatures can also lead to coking
The injection angle in the mixing chamber has a significant impact on coking; nozzles with different angles were fabricated through experiments to improve the combustion conditions.
It’s basically impossible for oil to coking in the combustion chamber; if coking does occur, your company should focus its efforts on the injectors and nozzles. The locations where coking tends to happen are usually in the mixing chamber and the reaction section, so we won’t discuss those here. It does not correspond to the original poster’s question
Excessively high or low oil temperatures can also lead to coking
The combustion chamber generally does not tend to coking; coking usually starts around the nozzle orifices and then spreads throughout the entire nozzle.
Some oils of low quality can also cause coking; the high-viscosity residue oil that was used in our facility some time ago is an example of this
It is mainly caused by poor fuel atomization and an inappropriate atomization angle of the fuel injector. Of course, the quality of fuel is also important; heavy oil with poor quality tends to cause severe coking.
First, consider the properties of the fuel; fuels such as heavy oil and residue oil need to be heated in order to be atomized. If the temperature is not high enough, the atomization effect is poor, which can lead to coking. Additionally, any imbalance in the air supply can also cause coking
Coking is closely related to the type of oil used. In our plant, burning residue oil led to frequent coking problems, and once coking occurred, it was easy for further coking to happen. Recently, we have been using RDS base oil, which is less prone to coking but more susceptible to flame dimming. The ratio of misted steam used along with the opening degree of the air valves remain crucial when burning oil. :lol
1 Observe whether coking often occurs in the same location, and then determine whether the oil gun is installed eccentrically; if it is, oil mist tends to accumulate and cause coking. 2 Considering the size of the air supply method, the spiral air supply method is preferable. 3 Check the level of impurities in the fuel to determine whether it is likely to clog the nozzle. 4. The atomization is poor; the combustion chamber produces black smoke, and unburned fuel oil accumulates and forms coke. Adjust the fuel-to-air ratio. 5 Is the air pressure sufficient to atomize the oil?
The atomization is not good; the air supply and oil amount are not appropriate. Pay attention to the oxygen content – it’s better to keep it between 7% and 9%. Also, pay attention to the direction of wind rotation
Note that if the wind rotation of the upper and lower nozzles of the fuel furnace is different, i.e., in opposite directions, it may also cause coking at the lower or upper nozzle
It is necessary to consider whether coking occurs as soon as it is put into use, or whether it results from changes in certain operational parameters after it has been in use for some time. The atomization is poor, leading to easy coking. The uneven mixing of fuel and air, along with localized high temperatures, can easily lead to fuel coking. If the air volume is too low, combustion is incomplete, and the C in the fuel precipitates, which also manifests as coking. A comprehensive analysis is required.