Method and device for deep oxidation of sweetening alkali liquor and separation of disulfide

Abstract

The invention relates to a method and a device for deep oxidation of sweetening alkali liquor and separation of disulfide. The method comprises the following steps: a, alkali liquor oxidation; b, primary separation; c, deep extraction; d, oil-gas separation; and e, oil-alkali separation. By using a liquor distributor and an air distributor, the alkali liquor is in full contact with the oxygen and the oxidation conversion speed; the disulfide is deeply extracted through a fibrous membrane extraction contactor, so that the contact area is enlarged, the extraction depth is increased, the content of the disulfide in the alkali liquor is reduced to be below 200ppm, the quality of the regenerated alkali liquor is improved; the tail gas after the reaction is absorbed by a diesel absorption tank, so that the pollution of the disulfide to the atmosphere is decreased; and the gasoline after the extraction is washed, so that the influence of the residual alkali liquor to the gasoline hydrogenation is prevented. The method and the device are simple in process, energy-saving, environmentally friendly, good in device controllability, stable in operation, in accordance with the market requirement and suitable for large-scale popularization.

Description

technical field [0001] The invention relates to an oxidation regeneration process of sweetening alkali liquor for liquefied petroleum gas, carbon five, light gasoline and other oil products in the field of petroleum and natural gas processing, in particular to a method and device for deep oxidation of sweetening alkali liquor and separation of disulfides. Background technique [0002] As the world's oil resources continue to be depleted, the content of sulfide in petroleum hydrocarbons is getting higher and higher. In a series of desulfurization processes, sulfide must be completely removed from petroleum hydrocarbons through chemical and physical processes without Discharge into the atmosphere and sewage, recycling, in order to avoid pollution to the environment. In the refining process of liquefied petroleum gas, carbon five, light gasoline and other oil products, the mercaptan sulfur in them is generally removed through alkali washing process, so that the sulfur content o...

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Problems solved by technology

At present, the oxidation regeneration process of this process has the following main problems: the lye oxidation tower adopts a packed tower structure, the air adopts a large air volume intake, the air distributor adopts an aperture of 10 mm or more, and the oxidation temperature is 55-65 ° C, resulting in gas-liquid emulsification in the tower Serious, the oxidation effect is poor, most of the generated disulfides are taken away with the tail gas, and a small part is emulsified with alkali solution, and the separation effect is poor, etc.

However, in this patent, only a small part of the lye is oxidized and regenerated, which is not suitable for demercaptanization of oil raw materials with increasingly high sulfur content; and the lye and disulfides have not been completely separated, and most of the disulfides are carried with the tail gas. Finally, it is discharged into the atmosphere; the gas distributor has high precision and is easy to block; it is oxidized by oxygen-enriched air, which is very dangerous; after oxidation, the lye is directly desulfurized, and disulfides will continue to be generated due to oxygen content and brought into the liquefied petroleum gas sulfuration effect

[0005] Chinese patent 201220012653.8 added a stripping tower to the oxidized lye, and used high air volume to blow off the disulfide in the oxidized lye; due to the use of two towers for the air injection process, the tail gas volume increased significantly. Therefore, the patent adds an exhaust gas treatment system

The patent has the following problems: some disulfide disulfides are taken away with the tail gas; the gas distributor has high precision and is easy to block; the tail gas treatment system is composed of a water washing tank, a dealkalization tank, an oxidation tank, a membrane separation tank, etc., and the investment in equipment is large Large, and in practical application, the disulfide in the tail gas can only be reduced from 10,000ppm to 5,000ppm, the treatment effect is limited, the lye after oxidation will directly remove the mercaptan, and the disulfide will continue to be generated due to the oxygen content, which will be brought into the liquefied petroleum gas. Sulfation effect

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