GB512395A - A process for desulphurising mineral oils - Google Patents

Abstract

512,395. Desulphurizing oils motor fuels. NAAMLOOZE VENNOOTSCHAP DE BATAAFSCHE PETROLEUM MAATSCHAPPIJ, and FIFE, J. G. Aug. 11, 1938, No. 2759/39. Divided out of and addition to 512,364. [Class 91] Low boiling mineral oils are freed from sulphur compounds, such as mercaptans, thioethers and alkyl thiophenes, without affecting aromatic hydrocarbons or mono-olefines, by extracting the oil with a selective solvent for sulphur compounds, separating the extract and treating it at a temperature not above 40‹C., with an aliphatic sulphonic acid, whereupon a further rafflnate and extract are formed and separated. The final raffinate free from sulphur compounds is combined with the first rafflnate to form a motor fuel. Naphtha, gasoline, kerosene, gas oil, from straight-run, cracked, or polymerized oils may be treated. Selective solvents specified are, sulphur dioxide and acetone, thiophene aldehyde, methyl or ethyl cyanide, ethyl cyanoacetate, nitroaniline, aniline, ethylene diamine, methoxy methyl cyanide, and methyl carbitol. Sulphonic acids specified are, methyl, ethyl, propyl, isopropyl, butyl, and amyl sulphonic acids, or the corresponding chlorsulphonic acids, used alone or diluted with a polar diluent, such as one of the selective solvents, alcohol, acetone, or water, or a hydrocarbon diluent, such as Edeleanu extract. Such diluted sulphonic acids are used with oils containing large amounts of olefines. Oil is introduced into an extraction zone B to which a selective solvent and an auxiliary solvent such as naphtha flow in countercurrent. The rafflnate containing paraffins, naphthenes and mono-olefines, passes to a separator 33 and then tank 34, and the extract containing aromatic, unsaturated, and sulphur compounds, passes to a still 32. The. solvent-free extract passes to a second countercurrent extraction zone A, which may be a packed tower, or mixers and settlers, where it is treated with the sulphonic acid and a light naphtha or white oil, as diluent. The extract free from hydrocarbons, passes to a settler 9 in admixture with water or alcohol which dissolves the sulphur compounds, leaving a sulphonic acid layer which passes to a vacuum still 11. The alcohol and auxiliary solvent are recovered from the extract in a still 14. The sulphur-free rafflnate consisting of aromatic and unsaturated compounds and auxiliary solvent is washed with water in a separator 19, distilled with steam at 21, and, if desired, finally treated with clay. This is then united with the first raffinate. In an example, 100 parts of cracked distillate boiling at 150-200‹C. containing 1.1 per cent. sulphur is treated with sulphur dioxide and octane, yielding 20 parts of extract containing 4.4 per cent. of sulphur. The extract is treated with methyl sulphonic acid and isopentane, yielding 12.2 parts of rafflnate containing 1.2 per cent. of sulphur, and an extract containing 14 per cent. of sulphur. The combined rafflnates form 92 parts containing .3 per cent. of sulphur.