The effect of process gas on the catalyst
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Effect of process gas on catalysts: The activity and service life of the K8-11 and QCS-01 catalysts are highly dependent on the H2S content, water vapor content in the process gas, as well as the bed temperature. It is necessary to maintain a stable H2S concentration in the process gas to keep the catalyst in a sulfided state. If the H2S concentration in the process gas fluctuates (that is, the H2S concentration varies above and below the H2O line in the graph), it will inevitably cause the catalyst to undergo repeated reversible cycles of sulfidation–hydrolysis–sulfidation. This damages the catalyst’s structure, reduces its mechanical strength, and increases pressure drop, thereby shortening its service life. 2. To prevent process gas from carrying water, which could lead to condensation and water ingress within the catalyst bed. As can be seen from the graph, an increase in the H2O vapor content has little effect on catalyst activity; however, a large amount of water ingress causes condensation within the bed, resulting in rapid cooling of the catalyst and clumping, thereby damaging it and rendering it inactive. 3. Control the inlet temperature of the shift converter to remain stable; during normal production, it is necessary to prevent the inlet temperature of the shift converter from fluctuating greatly. On the one hand, it is evident from the graph that large fluctuations in temperature can also cause the catalyst to undergo repeated reversible cycles of sulfidation–hydrolysis–sulfidation ； On the other hand, catalysts tend to lose their low-temperature activity after being used at high temperatures; at low temperatures, the CO conversion rate decreases, resulting in neither the desired gas product being obtained nor the raw materials being wasted.
The key is to keep the water vapor content entering the catalyst bed at a low level.
The concentration, pressure, temperature, and flow rate of the process gas, as well as its purity, have a significant impact on the catalyst
Indeed, these factors are all important influences on the service life of catalysts. The concentration of imported hydrogen sulfide must not be too low, as this can easily lead to desulfurization reactions. Additionally, the purification of process gases is crucial; an oil removal device must be installed before the shift converter. Water in the steam and oil in the gases can both cause the catalyst to clog, thereby reducing its service life. Regular maintenance of the catalysts is just as important as the sulfidation process itself.