Can sulfur be added to a water-coal slurry gasifier?
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Can the Tsinghua furnace water-coal slurry gasifier be used to add sulfur to raw coal?
Is the poster trying to change the catalyst for sulfidation reduction? It is possible to add sulfur to the raw materials as a catalyst for the sulfidation of the shift catalyst. The sulfidation process itself takes around 7 to 15 days. During this period, when the sulfur addition occurs while the gasification furnace is operating normally, hydrogen sulfide will have little impact on the furnace; however, it is best to avoid stopping the operation of the gasification furnace, as each start-up and shutdown can cause some damage to the furnace walls, especially since there are no refractory bricks in the combustion chamber of such furnaces.
For coal with extremely low sulfur content, the hydrogen sulfide level in the syngas may be below the minimum level required by sulfur-tolerant shift catalysts; in such cases, it is necessary to add sulfur to the coal.
Now, pre-sulfided catalysts are used for conversion catalysts; sulfiding is no longer necessary at all. If sulfur is added to the gasifier for sulfidation, the sulfidation costs would be extremely high.
Why is sulfur added to the gasifier? If a sulfur-resistant shift catalyst is to be used, and given the low sulfur content in the feed coal, such a catalyst may experience desulfurization under high water-gas ratios. The best approach is not to add sulfur; adding sulfur would increase the sulfur content in the feed coal. However, as the sulfur content rises, the material grade required for the equipment also increases, thereby raising the investment costs for the gasification unit. The best solution is to install a compressor that sends hydrogen sulfide back to the inlet of the shift reactor, thereby controlling the sulfur content in the syngas.
Question: What is commonly used for catalyst sulfidation? Can hydrogen sulfide be sulfided?
Carbon disulfide can be purchased for sulfiding; hydrogen can be obtained from syngas or gas produced by gasification, or hydrogen can also be bought for this purpose. As someone mentioned above, pre-sulfided catalysts are available in China, and all these options can be considered.
Now, some of the catalysts used in this transformation are completed through direct sulfidation. No secondary vulcanization is required. It’s relatively safe.