The main reasons for flashback in the gasifier
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This post was last edited by GSP on 2010-7-9 09:17. What are the reasons for backfire during the initial heating up and normal heating up of a vaporization furnace? And the handling methods, thank you. I’m a beginner seeking advice
The reasons for the temperature rise and backfire in the gasification furnace, as well as the measures to avoid backfire, include the following: ① Improper operation by the personnel during ignition can lead to backfire, and in more severe cases, it may cause a flash explosion. Therefore, operations must be carried out strictly in accordance with the procedural guidelines ； ②The liquid level in the gasifier is high, submerging the downcomer. At this point, reduce the amount of preheated water used, or increase the flow rate of the preheated water from the gasification furnace to the water seal tank, in order to lower the liquid level in the gasification furnace ； ③The amount of fuel used to heat the gasifier increases rapidly in a short period of time. At this time, a stable fuel supply volume is required, as well as a stable condition of the fuel delivery equipment; moreover, the speed at which the control amounts are increased or decreased during adjustments to the fuel volume is also important ； ④The load on the extractor is low; one reason for this is the small opening degree of the extractor. Additionally, when the gasification furnace starts to heat up during the warming process, adding fuel without increasing the extraction capacity can also lead to backfire. Therefore, during the heating or temperature-raising process of the gasifier, when more fuel is added, the load on the extractor for creating negative pressure also increases accordingly ； Another reason for the low load on the extractor is the low steam pressure; this may be due to water in the steam or simply a low pressure level. Therefore, it is necessary to take care of warming the pipes when steam is supplied, and to remove the condensate that forms in the steam pipes through the drain valves. It is also important to maintain an appropriate pressure in the steam pipes at all times ； ⑤The pressure of the compressed air used for fuel (diesel) atomization is low (in some units, it may not be compressed air but steam instead) ； It’s also possible that some units don’t have this, and instead use gas fuel to heat the furnace and raise its temperature). Therefore, in this case, it is necessary to ensure that the pressure of the compressed air is 0.05 MPa to 0.1 MPa higher than the pressure of the fuel (diesel) ； ⑥A clogged taphole can also cause tempering. Before heating up and igniting, a thorough inspection of the gasifier combustion chamber and slag outlet is carried out.
Reply 1# zhangzh41 1. Cut off the steam supply. 2. The gasification furnace has poor drainage and is blocked. Stop heating the furnace
The second floor explained it in great detail, haha, learn*learn*!:victory:
There is less steam, more fuel gas, and the liquid level in the vaporizer is high. There are all kinds of reasons for it.
1. The amount of steam drawn is low, resulting in insufficient negative pressure; 2. The liquid level in the quench chamber of the gasification furnace is high or drainage is poor, and the downcomer is blocked (keep an eye on the local level gauge). Additionally, the suction negative pressure should not be set too high, as this can easily cause the flame to go out
The root cause is still an insufficient or unstable negative pressure inside the furnace, and there are many reasons for this.
Monitor the pressure inside the furnace at all times (including static and dynamic pressures); an alarm is triggered promptly when the negative pressure is insufficient or when there are large pressure fluctuations, which helps to reduce the occurrence of tempering.
A low liquid level can also cause tempering.
During the initial furnace drying process in our plant, the main cause of tempering issues was unstable steam pressure at 1.1 MPa, along with fluctuations in the negative suction pressure. Secondly, it is possible to control the following aspects properly: 1. Keep the preheating water volume at 170, 2. Maintain the liquid level in the quenching chamber below 15% to prevent water sealing during tempering. 3. Open the manual valve on the non-overflow side of the water seal tank to lower the level of the water seal liquid.