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In terms of a cobalt molybdenum catalyst component, or in the role of the catalyst, the main catalyst is molybdenum, cobalt cocatalyst. So, for cobalt and molybdenum sulfide catalyst, which is mainly to complete the molybdenum sulfide. The vulcanization is generally based on molybdenum Mo + 6, Mo + 5, Mo + 4 valence state three kinds, Mo + 5 transform the transforming activity of the reaction, but, in practice, with Mo + 6 Mo + 4 coexisted should this molybdenum is not all restored. To ensure the safety of its cured completely, pay attention to the following points during vulcanization: 

 

(1) dry vulcanization. Sulfur in the catalyst must be completely dried. Therefore, generally before curing, the catalyst should be heated, the removal of adsorbed water, if this is not done, in the Mo-Co catalyst vulcanization reaction with H2S, hindered by the presence of water, converting OS. 

 

(2) increase the H2S concentration. Sulfur concentrations can ensure the needs of the vulcanization reaction and shorten the reaction time, but in the early sulfide H2S content not to mention too, should take gradual penetration of the way, to prevent overreact, causing the catalyst temperature fluctuation is too large. Vulcanization qualified appraisal, in addition to ensure proper curing temperature and curing time, the H2S content should export inlet H2S content equal to prevail. 

 

(3) a low temperature vulcanization. When the bed temperature reached 180 ℃, the gas inlet temperature was lowered to 170 ~ 180 ℃, followed by addition of CS2, H2S absorption zone allows the reaction of the catalyst to avoid the beginning of the reaction due to the temperature exceed 200 ℃ fierce prone to temperature spikes. The main sulfide phase 180 ~ 300 ℃, to ensure that the temperature is basically the temperature control at about 250 ℃, gradually increase the amount of CS2, analyze stove outlet H2S reach 1g / NM3 is qualified. 

 

(4) high-temperature processing. Generally, the cobalt-molybdenum catalyst at a temperature above 175 ℃ H2S absorption zone is followed with increasing temperature conducive to curing, but the temperature reached 450 ℃, the catalyst has reached the maximum value of the vulcanization, the temperature rises again , but reduced catalytic activity. Therefore, at the end of the basic curing catalyst, the catalyst bed temperature was raised to 450 ℃, morphology of Mo, Co, S will vary, the catalyst Co atoms in Mo-Co-S increases to a maximum in the form of value, the catalyst activity reached a maximum value. When the high temperature treatment, the concentration of CS2 is not necessarily very high, as long as appropriate to maintain.

 

(5) cobalt-molybdenum sulfide catalyst, sulfur and furnace temperature control relationship should be executed, "not to mention the warm sulfur mention, not to mention to mention warm sulfur" principle. 

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