Patent GB-617780-A (GB)
Title: Improvements in or relating to gas purification process
IPC: B01D53/14
Filed: 1946-02-12
Abstract: <PICT:0617780/III/1> Sulphur compounds are removed from industrial gases by scrubbing with an amine associated with an absorbent oil to form an aminesulphur complex, separating the gas from the amine and amine-sulphur complex and extracting the complex with water which is immiscible with the scrubbing medium.  Coke oven gas is scrubbed in a tower 1 with a wash oil containing 3-5 gms. per litre of piperidine to absorb sulphur compounds, especially carbon disulphide, carbonyl sulphide, carbon hydrogen sulphide, mercaptans, &c.  Piperidine vapours carried off by the gas react in a water scrubber 4 with carbon dioxide present in the gas, or hydrochloric or sulphuric acid, ammonium sulphate, &c. solutions may replace the water.  The scrubbing medium passes through a delay tank 8 to facilitate reaction between piperidine and sulphur compounds dissolved in the wash oil, the free piperidine content in the tank being restored by connection with the condenser 11 of a still 10 in which piperidine is vaporized off from salts formed in scrubber 4 and a still 33 in which with the aid of a stream of coke oven gas organic sulphur compounds are vaporised off from liquids mixed with an acidic reactant such as hydrochloric or sulphuric acid or ammonium sulphate in a chamber 30; or the sulphur compounds may be separated by absorption in light oil. The scrubbing medium from tank 8 flows into a contactor 13 containing water and consisting of a vertical pipe, e.g. 48 ft. high and 2 in. diameter with a top section 20 of 8 in. pipe. Tower fillings 24 above the 30 ft. level and 26 below the inlet destroy unstable oil-water emulsion, providing a quiescent zone 25 of revivified oil for re-use in scrubber 1 and a zone 27 of water solution free of oil, to be acidified in chamber 30.  The desulphurized piperidine sulphate solution from still 33, with piperidine carbonate from scrubber 4 is treated with sodium or calcium hydroxide in a sump 38 feeding still 10 in which free piperidine is vaporized.  In a modification, water solution from contactor 13 is mixed with half its volume of a creosote oil, benzene or other cyclic hydrocarbon, and treated for 15 minutes with carbon dioxide under 60 atmospheres pressure, the mixture then separating out to water solution which is passed to sump 38 and oil solution of sulphur compounds which is treated in desulphurizing still 33.  The scrubbing medium may comprise primary amines such as monoethanolamine and iso-octylamine or secondary amines such as morpholine and its homologues, or a hydrogenated tar base fraction obtained from a fraction originally including pyridine, quinoline, isoquinoline and their homologues. As solvent for the amine, water, aliphatic alcohols, ketones, mineral oils, coal tar oils, and petroleum wash or straw oils may be used.  The Specification as open to inspection under Sect. 91 comprises also the removal of inorganic sulphur, e.g. hydrogen sulphide or organic sulphur from other fluids such as hydrocarbon oils.  Also, the revivification medium in contactor 13 may comprise inorganic salt solutions, as of calcium chloride, sodium thiocyanate and alkali-hydroxides, and organic liquids such as tricresyl phosphate and glycerol.  This subject-matter does not appear in the Specification as accepted.