Reviewing the Old to Discover the New (Series 11)

The wet oxidation desulfurization technique is one of the widely used desulfurization methods in China’s chemical industry. As the name suggests, it involves using a dilute alkaline solution to absorb H2S from the gas phase; within the liquid phase that has absorbed H2S, the H2S is oxidized to elemental sulfur thanks to the action of an oxidation catalyst, which allows for its separation and recovery. Therefore, this technology includes H2S absorption, oxidation, and sulfur recovery. Compared with other chemical and physical methods: (1) this method is suitable for conditions where the H2S content in the feed gas is low (< 20 g/Nm3) and the CO2 content is high; it is thus applicable to the desulfurization of gases such as coal gas and coke oven gas. Hundreds of production units are currently in operation in the country. (2) The advantage of this technology is that it can directly oxidize H2S to elemental sulfur, eliminating the need for specialized Claus sulfur recovery units; it features a short process flow and simple operation. (3) The overall sulfur recovery rate of this technology (80%–85%) is higher than that of other associated Claus sulfur recovery methods. (4) The low sulfur capacity of the solution and the production of small amounts of by-products are the disadvantages of this technology. The low sulfur capacity results in utility costs accounting for over 50% of the desulfurization costs, while small amounts of by-products increase the consumption of alkalis, adding to the operational complexity. These limitations are also the key challenges that this technology must overcome.

Oxidize +4 sulfur to +6 sulfur, and absorb it with water to obtain sulfuric acid

Oxidative desulfurization is a method that uses oxidants to carry out oxidation reactions with hydrogen sulfide or sulfur dioxide in order to remove sulfur

Oxidative desulfurization is a desulfurization method that converts hydrogen sulfide (S) into elemental sulfur in the liquid phase

In fertilizer manufacturers that produce synthetic ammonia alcohols using fixed-bed batch gas generation, the desulfurization process in their production processes typically relies on wet oxidation for desulfurization, with dry desulfurization methods used as a supplementary step for further purification (such as using activated carbon desulfurizers). Among these wet oxidation methods, tannin-based desulfurization is the most common; in recent years, a certain amount of cobalt titanium phthalocyanine desulfurizer has also been employed. The wet oxidation desulfurization technique is one of the desulfurization methods widely used in China’s chemical industry. As the name suggests, it involves using a dilute alkaline solution to absorb H2S from the gas phase; within the liquid phase that has absorbed H2S, the H2S is oxidized to elemental sulfur thanks to the action of oxidation catalysts, which allows for the separation and recovery of this sulfur.