Liquefied petroleum gas desulfurization purification system and purification method

Abstract

The present invention discloses a liquefied petroleum gas desulfurization purification system. The system comprises a liquid-liquid mixed reaction unit, a liquefied petroleum gas separation unit, a desulfurization solution regeneration unit, a sulfur filtration unit and a chemical supplement unit. The invention also provides a purification method of the liquefied petroleum gas desulfurization purification system. By using a complex iron catalyst desulfurization solution, hydrogen sulfide in the liquefied petroleum gas can be converted into sulfur, and mercaptan in the liquefied petroleum gas can be converted into disulfides at the same time. Based on the purification method, the defects of using two sets of process in the traditional liquefied petroleum gas desulfurization can be overcome. The investment and operation costs can be greatly saved and the operation can be simplified. Also, the following defects are overcome: a lye needs to be discharged intermittently and a large amount of alkali residues are produced when the mercaptan is oxidized into the disulfides, so as to eliminate the alkali residues and protect the environment.

Description

technical field [0001] The invention belongs to the technical field of liquefied petroleum gas desulfurization, and in particular relates to a liquefied petroleum gas desulfurization purification system and a purification method. Background technique [0002] Liquefied petroleum gas mainly comes from catalytic cracking, delayed coking, atmospheric and vacuum, hydrocracking, continuous reforming and other devices in refineries. Its main components are C3 and C4 hydrocarbons and a small amount of C2 and C5 hydrocarbons. It also contains hydrogen sulfide, Sulfides such as mercaptans and COS. The liquefied gas from atmospheric and vacuum, hydrocracking, and continuous reforming units contains less olefins, and most of them are saturated hydrocarbons such as propane and butane. If it is used as civil liquefied gas, the total sulfur mass concentration after refining shall not exceed 343mgS / Nm 3 The product quality standard is sufficient; if it is used as a chemical raw material ...

AI Technical Summary

Problems solved by technology

The Merox extraction and oxidation process is simple, mature and reliable, and the mercaptan in the liquefied gas after removal can be less than 20 μg / g, but it needs to discharge the lye intermittently, resulting in a large amount of alkali residue, and the operation fluctuation is easy to cause the liquefied gas to carry lye and lye Catalyst loss, etc.

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