How to treat waste gas containing hydrogen sulfide with activated carbon

The hydrogen sulfide that pollutes the air mainly comes from natural gas purification, petroleum refining, coal gas and coking plants and chemical plants, and the microbial decomposition of sulfur-containing waste.

Treatment methods include improved Claus method, iron oxide method, ethanolamine method, hydroquinone method, ammonia absorption picric acid catalytic method and activated carbon catalytic oxidation method.wholesale activated carbon pellets  Among them, activated carbon catalytic oxidation method is to oxidize hydrogen sulfide on activated carbon to sulfur Because of its easy operation, it is widely adopted by everyone.

Organic solvent extraction or steam distillation can be used to recover elemental sulfur, or ammonium sulfide aqueous solution can be used to extract elemental sulfur. Hydroxide sulfide generates elemental sulfur, but side reactions may also occur to generate sulfur dioxide. Therefore, it is necessary to select reaction conditions and use accelerators to avoid or reduce these side reactions.

When the oxygen content in the gas mixture containing hydrogen sulfide increases from 1:1 to 1:6, the oxidation rate of hydrogen sulfide increases from 25% to 30%. When the amount of activated carbon increases, the oxidation rate of hydrogen sulfide will increase to more than 90%. When the temperature is 120°C, the oxidation rate is very fast, and the rate increases as the temperature rises.

The temperature of the activated carbon bed should be less than 60℃. Due to the large reaction heat effect, this method is not suitable to treat waste gas with a hydrogen sulfide concentration greater than 900g/m3. Generally, activated carbon contains a lot of chemically adsorbed oxygen. After the activated carbon is degassed, the adsorbed oxygen is exhausted, so that the active site chemically adsorbs sulfur.

When the active part of yongruida carbon is blocked due to the adsorption of oxygen and sulfur, the oxidation efficiency is greatly reduced, which clearly shows that the active part of activated carbon is related to catalytic activity, and the surface area of activated carbon has nothing to do with catalytic activity. Because degassed activated carbon has roughly the same surface area as undegassed activated carbon, it is a more effective catalyst.

Activated carbon will remove some impurities such as iron or sodium that can promote hydrogen sulfide by pickling, thereby reducing the catalytic activity of activated carbon. Adding an accelerator will increase the efficiency of the active site and reduce the side reactions of sulfuric acid.