HYDROGEN SULFIDE-CONTAINING CRUDE OIL PRETREATMENT PROCESS Russian patent published in 2004 - IPC

FIELD: crude oil treatment. SUBSTANCE: invention relates to treatment of sulfur oils and gas condensates with high hydrogen sulfide and mercaptan contents. Hydrogen sulfide-containing oil treatment consists in multistage separation thereof and purging with hydrocarbon gas in a separation stage or in additional desorption column at 25-70 C and pressure 0.1-0.6 MPa until removal of 60 to 90% of hydrogen sulfide present followed by post-treatment of oil to remove remaining amounts hydrogen sulfide and light mercaptans via addition of, at stirring, effective amounts of mono- and/or dimethanolethanolamine (monoethanolamine/formaldehyde reaction products) followed by keeping the mixture for at least 5 min at 10-70 C and 0.1-0.6 MPa. More specifically, mono- and/or dimethanolethanolamine are added in the form of aqueous or water-alcohol solution obtained from interaction of monoethanolamine with 30-40% aqueous or water-alcohol solution of formaldehyde at molar ratio 1: (1-4) and in amounts 4-15 g per 1 g of residual hydrogen sulfide and methyl- and ethylmercaptans. In order to reduce consumption of reagent and to intensify treatment of crude oil with abnormally high content of hydrogen sulfide and mercaptans, compressed air is additionally introduced in amounts 0.5 to 1.5 mole oxygen per 1 mole residual hydrogen sulfide. Hydrocarbon gas used as purging gas is crude oil separation gas or natural gas preliminarily freed of hydrogen sulfide and employed in amounts 2.5 to 12 cu.m per 1 cu.m crude oil. EFFECT: reduced residual content of hydrogen sulfide and mercaptans in commercial petroleum to the level of current requirements without loss of yield. 8 cl, 1 dwg, 1 tbl, 7 ex