Heavy oil separation method

Abstract

The invention discloses a heavy oil separation method. With heavy oil as the raw material, the method adopts a mixed solvent composed of two solvents i.e. A and B with different molecular weights for extraction in two stages of extraction sections connected in series. Specifically, the method comprises: first conducting extraction at a first stage extraction section which has a pressure and temperature higher than the critical pressure and critical temperature of the solvents; introducing the supercritical fluid obtained at the first stage extraction section and the extracted distillate oil into a second stage extraction section, further performing separation at the same pressure and an operating temperature between the critical temperature of A and B, subjecting the supercritical fluid from the second stage extraction section and the extracted distillate oil to pressure reduction, and then bringing them into a separator; and adjusting the extraction pressure to obtain narrow distillates of different boiling ranges. The method disclosed in the invention increases the yield of extracted distillate oil, and also guarantees fine separation at the same time. The method has the characteristics of high separation precision and high selectivity, etc.

Description

technical field [0001] The invention relates to a method for separating hydrocarbon mixtures, in particular to a method for separating hydrocarbon mixtures by means of supercritical extraction. Background technique [0002] Crude oil has become a development trend in recent years from inferior quality to heavy quality, and the vacuum residue content is as high as 40% to 60%. In order to make full use of limited oil resources and meet the growing demand for light oil products, it is necessary to lighten heavy oil. Since the composition and properties of various heavy oils vary greatly, it is necessary to conduct a comprehensive study on them to clarify their differences in composition and properties. Petroleum heavy oil, such as atmospheric residue, vacuum residue and other heavy products produced during petroleum processing, has the characteristics of high boiling point, poor thermal stability, and complex composition and structure. To evaluate the composition and structur...

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Problems solved by technology

There are two problems with this method: one is that the chromatographic separation method is cumbersome, and the amount of sample obtained is very small, and it is difficult to obtain various data and information required for follow-up research; the other is that the separation principle of chromatography is different from the production process Too far away, the resulting research results are not easy to use in actual production

[0004] The above-mentioned method has the following problems: 1. The raw material oil flows upwards through the temperature-increasing section as the supercritical fluid rises, the density of the supercritical fluid becomes smaller as the temperature rises, and the solubility decreases, so some raw material oil is precipitated and refluxed, but the raw material oil It is still unavoidable that some large molecular weight components are entrained, resulting in poor extraction and separation effects; 2. In the case of other extraction conditions being fixed, the extraction yield is proportional to the extraction time, so it takes a long time to obtain a higher yield. 3. The narrow fraction separated by single solvent extraction is relatively wide, resulting in the molecular weight and composition structure of the extracted fraction not concentrated, and the separation is not fine enough

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