Methyl Mercaptan from Natural Gas, Sulfur and Methanol (H2 Intermediate)

Hydrogen Synthesis. In a partial oxidation (POX) reactor, natural gas is partially oxidized with air, forming carbon monoxide and hydrogen, with steam added to promote a CO shift reaction that generates additional hydrogen and carbon dioxide. Next, a water-gas shift is promoted by adding more steam to the POX reactor outlet stream, reacting with the remaining carbon monoxide to produce more hydrogen and carbon dioxide. Water is removed via condensation, and carbon dioxide and other impurities are removed using a pressure swing adsorption (PSA) system, leaving pure hydrogen to be used for H2S production.

H2S Synthesis. In a packed bed reactor, hydrogen is bubbled into molten sulfur, forming a reaction mixture that passes through a catalyst bed, generating H2S. The stream leaving the reactor is quenched, then cooled in heat exchangers to recover vaporized sulfur. The H2S proceeds to methyl mercaptan synthesis.

Methyl Mercaptan Synthesis. First, vaporized methanol is mixed with H2S to form a feed stream with the desired molar ratio. The mixture is then preheated and fed to a packed bed tubular reactor where it reacts to form methyl mercaptan (MSH) and water. The reactor effluent is cooled and sent to the purification stages.

Methyl Mercaptan Separation. The reactor effluent is first condensed, creating an organic and an aqueous condensate; the uncondensed stream being washed with methanol, which is then mixed with the aqueous condensate. Unreacted H2S is recycled to the MSH Synthesis reactor feed. Both condensates undergo distillation to recover Methyl Mercaptan, methanol, and remove impurities. Methyl mercaptan is further distilled, separating it from dimethyl sulfide and other components. The purified MSH is then stored as the final product.