GB715180A - Improvements in or relating to recovery of free sulfur from sour hydrocarbon gases - Google Patents

Abstract

<PICT:0715180/III/1> Elemental sulphur is recovered from a gaseous hydrocarbon stream containing hydrogen sulphide by diverting about one-third of the stream, removing from this diverted stream the hydrogen sulphide content, which is reacted with oxygen or air to produce sulphur dioxide, mixing the sulphur dioxide thus formed with the undiverted hydrogen sulphide-containing stream and allowing the mixture to react to produce sulphur which is separated. As shown in the Figure, sour hydrocarbon gas, preferably containing at least 6 per cent. of hydrogen sulphide enters the system at pipe 2, two thirds being passed through pipe 4 and the remaining third being diverted to a scrubber 6 where it meets a hydrogen sulphide absorbent such as an alkylol amine solution. The hydrogen sulphide-free gas is drawn off at 8 and the rich alkylolamine solution passes through line 10 and heat exchanger 12 to a regenerator 14, where the hydrogen sulphide is desorbed by the action of vapours entering at 20 from reboiler 18 to which the lean alkylolamine solution is passed through line 16. Regenerated absorbent solution returns to the absorber 6 by line 22 having been cooled to the gas inlet temperature (100 DEG F.) by cooler 24. The hydrogen sulphide from regenerator 14 is chilled at 28 and after removing condensate in 30, passes by pipe 34 to a furnace 40 in admixture with air from 36. The mixture is burned at 1900 DEG F. and after cooling to 1000 DEG F. rejoins through pipe 42, the undiverted original hydrocarbon stream from 4. The mixture enters the converter 44 packed for example with bauxite at 450 DEG F. and leaves at 600 DEG F. to pass a condenser 48 from which sulphur is removed at 50 at 350 DEG F., then to a smaller converter 56 and a further condenser 60 from which liquid sulphur at 300 DEG F. is withdrawn at 62. The uncondensed gases containing hydrocarbons and inerts leave through pipe 64 and may be joined with purified hydrocarbon from line 8. The tail gas in line 64 may be sent through a further converter system 74. 76 where further sulphur is separated, and thence through pipe 80 to join the inlet stream to the absorber 6. The gas leaving the furnace 42, consisting largely of sulphur dioxide and nitrogen may if desired be by-passed at 41 to an absorption desorption system 43 whereby nitrogen is separated and vented; pure sulphur dioxide is then fed through line 45 to the converter 44.