| US 7,588,627 B2 | ||
| Process for the removal of H2S and mercaptans from a gas stream | ||
| Wiebe Sjoerd Kijlstra, Amsterdam (Netherlands); Josephus Norbertus Johannes Jacobus Lammers, Heemstede (Netherlands); and Clas Ingemar Wernersson, Gothenburg (Sweden) | ||
| Assigned to Shell Oil Company, Houston, Tex. (US) | ||
| Appl. No. 10/553,366 PCT Filed Apr. 13, 2004, PCT No. PCT/EP2004/050506 § 371(c)(1), (2), (4) Date Oct. 13, 2005, PCT Pub. No. WO2004/091754, PCT Pub. Date Oct. 28, 2004. |
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| Claims priority of application No. 03252485 (EP), filed on Apr. 17, 2003. | ||
| Prior Publication US 2006/0188424 A1, Aug. 24, 2006 | ||
| Int. Cl. B01D 53/14 (2006.01) | ||
| U.S. Cl. 95—187 [95/199; 95/235; 423/243.01] | 8 Claims |
| 1. A process for the removal of H2S and mercaptans from a gaseous hydrocarbon stream comprising these compounds, which process comprises the steps of:
(a) removing H2S from the gaseous hydrocarbon stream by contacting the gaseous hydrocarbon stream in a H2S -removal zone with a first aqueous alkaline washing liquid buffered at a pH between 4.5 and 10, at a temperature between
5 and 70° C. and a pressure between 1 and 100 bar, to obtain a H2S -depleted gas stream and a sulphide-comprising aqueous stream;
(b) removing mercaptans from the H2S -depleted gas stream obtained in step (a) by contacting the H2S -depleted gas stream in a mercaptan-removal zone with a second aqueous alkaline washing liquid buffered at a pH between
5.5 and 10, at a temperature between 5 and 70° C. and a pressure between 1 and 100 bar, wherein the pH of the aqueous alkaline
washing liquid in the mercaptan-removal zone is higher than the pH of the aqueous washing liquid in the H2S -removal zone, to obtain a mercaptan-depleted gas stream and an thiolate-comprising aqueous stream, said mercaptan-depleted
gas stream having a level of H2S below 10 ppmv and a level of mercaptans below 6 ppmv;
(c) contacting the combined aqueous streams comprising sulphide and thiolates obtained in step (a) and step (b) with sulphide-oxidizing
bacteria in the presence of oxygen in an oxidation reactor to obtain a sulphur slurry and a regenerated aqueous alkaline washing
liquid;
(d) separating at least part of the sulphur slurry obtained in step (c) from the regenerated aqueous alkaline washing liquid;
and
(e) recycling the regenerated aqueous alkaline washing liquid from the oxidation reactor to the H2S -removal zone in step (a) and to the mercaptan-removal zone in step (b).
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