What is the performance of iron-molybdenum catalysts after regeneration?

Catalyst suppliers claim that there is basically no impact, but in reality, the activity decreases significantly and the regeneration cycle becomes longer; as a result, most users do not use this method for regeneration.

It is recommended not to reproduce them. Our factory tried it as well, and it only lasted for a month

I regenerated the small iron molybdenum unit during last autumn’s inspection and have been using it ever since; the results have been very good

How is the iron-molybdenum catalyst regenerated? What gas and what regeneration conditions? :handshake

Regeneration of iron-molybdenum catalysts: After being used for a period of time, these catalysts accumulate a large amount of carbon black on their surface, which reduces their activity and increases resistance, forcing their replacement. Regeneration is possible during production by using oxygen to burn off the carbon on the surface, thereby restoring the catalyst’s activity and reducing costs. 1. Regeneration principle: C + O2 == CO2 + Q; 2FeS + 2O2 == 2FeO + SO2↑ + Q; MoS + 3O2 == MoO2 + 2SO2↑ + Q. 2. Perform action a. Close the inlet and outlet valves of the regenerative iron-molybdenum converter, slightly open the vent valve to slowly reduce the pressure to atmospheric level, and then install a blind flange at the outlet valve to isolate it from the production system. b. Open the nitrogen valve (or introduce steam) for purging, so that the concentration of flammable gases CO + H2 is kept below 0.5%. At the same time, cool down the system; once the temperature drops to 250°C, air is gradually introduced into the furnace to facilitate regeneration. The amount of air added is increased gradually, from an oxygen content of 0.1% in the initial mixture to 0.5%. After adding air, it is important to ensure that the temperature rise of the bed does not exceed 300°C per hour, with the maximum temperature not exceeding 450°C. If the temperature rises too quickly, the amount of air introduced must be adjusted promptly. If the temperature rise is too rapid, steam can be used for adjustment. c. When the bed temperature stops rising and shows a downward trend, the temperature of the inlet gas can be increased appropriately; once the temperature stabilizes, the air flow rate can be increased gradually. This process is repeated. When the hot spot in the bed reaches 450°C and the oxygen content rises to 3%, and when the oxygen contents in the inlet and outlet gases are equal, with no further increase in CO and CO2 levels in the outlet gas, the oxygen content in the inlet gas can be increased to 3%. Maintaining this temperature for 6 hours indicates that the regeneration process is complete. d. During the regeneration process, the oxygen and CO2 contents in the inlet and outlet gases are analyzed every half hour; when there is no change in the oxygen and CO2 levels in these gases, it can be considered that the regeneration is complete. Before being put into use after regeneration, the regenerated iron-molybdenum catalyst still needs to undergo sulfidation treatment before it can be utilized. This post was last edited by A Jian on 2009-3-3 21:00]

1. If it is being used normally without overheating, or if the overheating is not severe, it can be regenerated using the above method; however, the temperature must be carefully controlled. 2. If the temperature rises above 550 degrees due to high oxygen levels during production, causing the catalyst to sinter, it is best not to try to regenerate it. It’s futile.

The performance after regeneration is certainly not as good as before, and this is directly related to the content of organic sulfur in the gas; if the imported gas contains only a few dozen milligrams of organic sulfur, then the performance will be good. If the coal sulfur content in the region is high, the results will not be very good.