FIELD: oil and gas industry.
SUBSTANCE: invention relates to desulphurisation of cracked naphtha by interaction of hydrogen with organic sulphur compounds present in the supplied raw material. The invention relates to a hydrodesulphurisation method of cracked naphtha and involves the following: supply of the cracked naphtha to a single-pass reaction zone with a fixed layer, which contains a hydrodesulphurisation catalyst; removal of an outgoing flow and its supply to a separation zone for removal of H2S from there and obtaining a purified outgoing flow. An analysis of the purified outgoing flow is performed to determine boiling temperature, at which maximum rate of descent of bromine number is indicated in a chart of dependence of bromine number on temperature for the purified outgoing flow. The purified outgoing flow is supplied to a rectification column for separation of the purified outgoing flow into a light fraction and a heavy fraction having an initial boiling point as per ASTM D-86, which is spaced within 30°F (17°C) from the boiling point, at which an analysis of the purified outgoing flow shows maximum rate of descent of bromine number in the chart of dependence of bromine number on temperature. Light and heavy fractions are extracted, and at least some part of heavy fraction is recirculated to a single-pass reaction zone with a fixed layer, where the ratio of the recirculated heavy fraction to the cracked naphtha supplied to the single-pass reaction zone with a fixed layer is in the range of approximately 0.25:1 to approximately 10:1. The invention also relates to other methods of hydrodesulphurisation of a flow of the cracked naphtha.
EFFECT: obtaining hydrodesulphurised cracked naphtha having the content of total sulphur of less than 10 ppm by weight.
28 cl, 6 dwg, 4 ex
