5. Risks associated with the presence of hydrogen sulfide and mercaptans in raw materials of petroleum origin

Petroleum gases and crude oil contain impurities such as hydrogen sulfide, mercaptans and sulfur-containing organic substances. Combustion of non-desulfurized oil will lead to the production of sulfur dioxide and its emission up the chimney. The use of low-sulfur oil in combustion processes is therefore a more environmentally-friendly practice. Petroleum gas and petroleum cuts used in petrochemical processes must first be desulfurized for specific reasons: impurities containing sulfur are poisons for the catalysts used in these processes. This is particularly true of precious metal catalysts. Petroleum gas desulfurization can be achieved by passing the process gas over 4 A molecular sieves to remove sulfur-containing impurities from the gas stream. Regeneration of the molecular sieves by heating under inert gas produces off-gas rich in hydrogen sulfide, mercaptans and other organic sulfides....