I would like to know the main components of the exhaust gases emitted after producing 3 million tons of methanol per year and recovering sulfur via the Claus process

Desulfurization absorbs hydrogen sulfide and carbon dioxide. In the sulfur recovery process, hydrogen sulfide is essentially converted into sulfur, while carbon dioxide remains behind. Hydrocarbons are also burned to produce carbon dioxide. Then there’s nitrogen, which is present in air at a concentration of 79 percent; it’s easy to see then that nitrogen constitutes the largest proportion in the exhaust gases. Therefore, the highest component in sulfur exhaust gases is nitrogen, accounting for around 70-80 percent; followed by carbon dioxide, at about 10 percent. The figures mentioned above refer to the gas after cooling in the quench tower, with a water vapor content of around 5 percent. Before cooling, the water vapor content was close to 30 percent, and calculations can be made based on this. The calculations for reactions and material balance are quite simple; with the composition data of the acidic gases, it’s easy to determine how much air is required, how much carbon dioxide is produced, how much water is generated, and how much nitrogen remains.

If a combustion process is added after sulfur recovery, then the main pollutants will be SO2 and nitrogen oxides.

Over 90% is nitrogen, with a small amount of sulfur dioxide and nitrogen oxides

Chelated iron can remove all hydrogen sulfide from exhaust gases