Seeking help regarding sulfur poisoning in hydrogen production converters

First of all, your question isn’t very clear – are you asking about sulfur poisoning in nickel-based conversion catalysts (steam reforming catalysts), or in copper-based conversion catalysts (methanol-to-water conversion catalysts)? 1. To determine whether there is poisoning of the nickel-based conversion catalyst, it is necessary to observe that under identical water-to-carbon ratios, operating pressures, and temperatures, if the conversion rate drops sharply, the residual methane level increases, and heat spots or red areas appear in the upper sections of the furnace tubes, this can indicate that catalyst poisoning is responsible for the decline in its activity. (If carbon deposition is caused by an imbalance in the water-to-carbon ratio, in addition to the redening of the upper furnace tubes, there is also an increase in the pressure drop across the conversion tubes.) Sulfur poisoning is just one type; chlorine and arsenic can also cause catalyst poisoning. Sulfur and chlorine poisoning are relatively common, while arsenic poisoning occurs less frequently. Sulfur and chlorine poisoning is reversible. Sulfur and chlorine poisoning is a process of gradual downward spread, affecting the entire reaction tube from top to bottom. After sulfur and chlorine poisoning of the upper catalyst layer, the catalyst can be regenerated by reducing the sulfur and chlorine content in the feedstock (or by operating the catalyst in its reduced state), but regeneration due to chlorine poisoning is more difficult. The recovery of activity after regeneration is not high; generally, a recovery of 60% is considered good. If the factory cannot withstand the impact on production caused by reduction and regeneration, the catalyst is usually replaced. Sulfur poisoning is usually introduced through hot air, while chlorine poisoning is usually introduced through steam. 2. Regarding sulfur poisoning of the methanol conversion catalysts (copper-based catalysts), since these catalysts have high activity, they lose their functionality once poisoned by sulfur; after sulfur is removed from the feedstock, the sulfur poisoning of the catalysts generally does not recur. The same chlorine can also cause catalyst poisoning, and in both cases such poisoning cannot be reversed through regeneration; after regeneration, the copper grains grow larger and some activity is retained, but the activity level can usually only be restored to about 30% of its original value. In cases of poisoning, it is recommended to replace the catalyst. Sulfur is usually introduced into methanol, and in addition to methanol, chlorine is also introduced by deionized water.

Hello, may I ask why the activity of the conversion catalyst can only be restored to 60% due to chlorine poisoning?

Because when catalysts poisoned by chlorine are activated under laboratory conditions, their activity cannot be fully restored (usually only about 80% of the original level is regained); whereas when catalyst activation takes place in industrial plants, the activation conditions are not as favorable as those in the laboratory, and a recovery rate of 60% is already considered a good result.

Have you compared conversion agents used domestically with those used abroad? Are foreign conversion agents more tolerant to sulfur and chlorine?