H2 content in the process gas
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There are many side reactions in the sulfur production reactor; one of these reactions is the thermal decomposition of H2S to produce H2. Has anyone conducted analytical tests on the H2 content in the gas from the Claus process or in the exhaust gases during actual operation, to determine what the actual H2 level is? If the hydrogen content at the outlet of the hydrogenation reactor is controlled at the lower limit, provided that an excess is ensured, can this amount of hydrogen meet the requirements of the hydrogenation reaction? In the exhaust gas hydrogenation section, apart from the online reduction furnace, are there any plants where the hydrogenation reactor does not require additional hydrogen supply?
This post was last edited by ylb913 on 2016-7-14 at 11:42. Under normal air supply conditions, the hydrogen content in the exhaust gases is approximately 1%. The HCR process used by the Italian company Nige does not require an online furnace or external hydrogen supply; instead, it involves appropriately reducing the amount of air supplied, thereby reducing the demand for hydrogen. In China, it is known that only Huizhou uses this HCR process. One of the reports mentioned that approximately 6% of hydrogen sulfide undergoes cracking to produce hydrogen; the hydrogen sulfide content in the acidic gas is around 65%. Assuming a gas-to-air ratio of 1.7, the maximum hydrogen content should not exceed 65*0.06/270 = 1.4%
We analyze that the H2 content in sulfur exhaust is around 2%, and the dissociation of H2S is highly dependent on the furnace temperature. However, based on operational tests, attempting to raise the furnace temperature by diverting acidic gas from Zone 2 has the opposite effect. The reason seems to be that the acidic gas does not stay in the furnace long enough, which affects the furnace’s conversion rate; as a result, the hydrogenation reactor consumes more gas and the temperature rises further. However, when increasing the acid gas in the later stage, no analysis was conducted; it is not clear whether H2S, SO2, and H2 increased simultaneously in the process gas. As for the amount of acid gas used in the second stage, that is another issue.