Method for recycling disulfide during production of low-sulfur MTBE (methyl tert-butyl ether) product

Abstract

The invention relates to a method for recycling disulfide during production of a low-sulfur MTBE (methyl tert-butyl ether) product. The method comprises the following steps: feeding mixed C-4 into a cutting tower, reflowing based on partial light C-4 from the tower top as a liquid phase, and feeding the residual light C-4 as feedstock into a MTBE reaction system to obtain an MTBE product; extracting maleic, n-pentane, ethanethiol, isopropyl mercaptan and n-propanethiol from a side line opening, wherein the discharge at the tower bottom is sulfur mixture; and sending disulfide to a sulfide fractionating tower, separating dimethyl dithio from the tower top, and separating diethyl dithio mixture from the tower bottom. The MTBE product produced by the invention is high in purity and low in sulfur content, and only contains 2-3mg / kg in general; the method has the features of simple process, advanced technology, simple and convenient control operation, low energy consumption and strong practicability.

Description

technical field [0001] The invention relates to a method for pre-deeply removing and recovering disulfides in MTBE, belonging to the technical field of oil refining and chemical industry. Background technique [0002] At present, the sulfur present in MTBE itself is generally removed by distillation or absorption. The distillation method mixes sulfur-containing MTBE with light oil, and the mixed mixture enters a rectification tower, and the sulfur compounds in sulfur-containing MTBE are removed through rectification in a rectification tower. The light oil is reformed with a boiling point greater than 60°C Gasoline, straight-run gasoline after hydrodesulfurization, coker gasoline after hydrodesulfurization, aviation kerosene or light diesel oil, the amount of light oil added is 50wt%-100wt% of the total weight of sulfur-containing MTBE. The disadvantages of this method are: 1) The consumption of light oil is large; 2) The sulfur in MTBE is transferred to the light oil, and t...

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Problems solved by technology

[0005] The content of the method for producing low-sulfur MTBE products of the present invention to reclaim disulfides is: according to the difference of each component in the carbon four raw material and the boiling point of sulfur impurities, it is sent into the carbon four component splitting tower: overhead distillation The output is light carbon four, and this stream is used as the raw material of the MTBE device; heavy carbon four is extracted from the side line, mainly containing heavier components such as carbon five, butene, ethanethiol, isopropyl mercaptan, and n-propylene mercaptan. It accounts for about 8% to 15% of the total carbon four components. After extraction, it can be mixed with the remaining carbon four of the MTBE unit and enter the finished liquefied gas tank area. The purpose of extraction is to reduce the MTBE unit under the condition that the output of MTBE remains unchanged. Raw material feeding amount and improve the purity of MTBE product and reduce the sulfur content of MTBE product; Set disulfide circulation feeding line on the bottom tray, used to solve the disulfide content in the C4 raw material is small, the bottom of the tower The problem of difficult liquid level control; the output from the bottom of the tower is disulfide. When the middle liquid level slowly accumulates to a certain height, start the feed pump of the disulfide fractionating tower to send the disulfide to the middle of a specially designed, intermittently operated disulfide fractionating tower. The top of the tower produces disulfide Methyl disulfide (DMDS) and diethyl disulfide (mixture) are produced at the bottom of the tower, which are used as chemical raw materials or products to increase the economic benefits of the enterprise

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