Carbonization regeneration of cobalt-molybdenum catalysts

Our catalysts have never been subjected to carbonization treatment (cobalt-molybdenum-based sulfur-resistant shift catalysts have been used since 1995). The operating procedures are mentioned in the catalyst user manual provided by Qingdao Lianxin – but what exactly are those procedures? Can burning charcoal burn away things like coal ash that result from gasification?

I’ve only heard of this process; I’d like to learn more about it in detail as well

The Shell gasifier operates at high temperatures, and its gas contains no tar, middle oil, ash, etc. The Lurgi gasifier operates at lower temperatures, and its gas production mechanism is different; carbonization treatment of the catalyst can be applied to reduce production costs.

This post was last edited by 654262293 on 2010-9-25 at 17:29. By adding a small amount of air to nitrogen, O2 reacts with coke at a certain temperature to produce CO2 and CO. Maintain the inlet temperature of the conversion furnace at around 300 degrees, with the hotspot temperature in the bed ranging from 450 to 500 degrees. When burning carbon, keep the system pressure below 3.0 MPa, but not too low. After introducing air, closely monitor the temperature changes in the catalyst bed to prevent overheating. When the temperature rises rapidly, cut off the supplied air immediately and use nitrogen to cool it down as fast as possible. The process ends when no CO2 is detected at the converter outlet, indicating that carbon burning has ceased. (Excerpted from Qilu Keli Company’s catalyst manual, shared with everyone)

Reply to 5# 654262293: When the catalyst is in use, dust and tar present in the gas can clog and cover part of the catalyst, resulting in a decrease in its activity; it therefore needs to be regenerated to restore its activity. After the raw gas supply was cut off and the appropriate blind flanges were installed, medium-pressure steam in a weight ratio of 0.1–0.3:1 to that of the catalyst was introduced into the regeneration system. The temperature of the catalyst bed was increased at a rate of 84°C per hour until it reached 370–400°C; thereafter, steam continued to be supplied until the condensate in the gas stream contained virtually no impurities as detected by sampling. Process air is introduced. After the air and steam are thoroughly mixed in the regeneration mixer, the mixture containing about 2% (by volume) air enters the bed. By monitoring the bed temperature for 1 hour, it is possible to observe the combustion of the carbon-containing substances in the bed; the proportion of air in the steam must not exceed 5%. The amount of air supplied can be adjusted as appropriate to keep the bed temperature below 501°C. When the CO2 content in the non-condensable gases in the exhaust gas is less than 2% and the oxygen content is around 15%, it can be considered that the regeneration process is complete; after stopping the supply of air, steam supply should also be halted.

Blow the shift converter with low-pressure superheated steam for 2-3 hours to loosen the bed layer. Process air and low-pressure superheated steam are introduced into the converter, where the temperature is increased at a rate of 30°/h. When the oxygen content in the regeneration exhaust gas reaches 20% and the furnace temperature starts to drop, the supply of steam is gradually reduced until it is stopped, while the amount of air supplied is increased. If the oxygen content remains around 20% for 2 consecutive hours and the bed temperature does not rise, then regeneration can be considered complete.

This post was last edited and replied to by 654262293 on 2010-11-9 at 10:14. Reply to 7# laoyang3815: Friend, what process do you use for gas production? Is it a coal lump? Is carbonization used to process tar or coal ash?

I really want to know the methods for regenerating cobalt-molybdenum catalysts right now; it’s extremely urgent. . . . . . .

Catalyst regeneration is only applicable when a Ruhr furnace is used in front. Due to the low temperature in the Ruchi furnace, the process gas in subsequent stages contains oil, hydrocarbons, and other impurities. The impurities and carbon carried in the feed gas accumulate on the upper catalyst layer, and regeneration is typically achieved by adding a small amount of air to the steam. At a certain temperature, a reaction takes place with it to produce CO2/CO, releasing a large amount of heat; therefore, the process must be carried out slowly to prevent the catalyst from being damaged due to overheating. The progress of the oxidation reaction is determined by changes in the bed temperature and the CO2 content at the outlet. Through sampling analysis, the regeneration process is completed when the CO2 content in the non-condensable gases in the outlet gas is less than 2%, and the oxygen level is around 15%.

This post was last edited and replied to by huixuandemeng on 2011-12-2 at 13:53. Reply 7# laoyang3815: I’m not sure if your method of operation is correct, but in our field of recycling, the oxygen content is strictly controlled; it cannot be 20% as you mentioned – such a high level can cause fires inside the furnace and damage the furnace itself. We don’t use low-pressure steam either; we use medium-pressure steam