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Oxidation regeneration method of alkali liquid containing sulfur

A technology of lye and disulfide, applied in the petroleum industry, treating hydrocarbon oil, refining hydrocarbon oil, etc., can solve problems such as insufficient optimization of the process, difficult stable operation, and increased operating costs, so as to increase the oxidation rate and save the separation link, cost-saving effect

Inactive Publication Date: 2017-07-11
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 1. The conversion rate of sodium mercaptide in the regeneration process is low, and the conversion rate of sodium mercaptide in the oxidation tower is usually only about 30% to 50%, which leads to the gradual accumulation of sodium mercaptide in the circulating lye, mainly manifested in the high content of mercaptan in the product
[0005] 2. The product disulfide removal rate is low. Due to the microemulsification of disulfide and the small difference in specific gravity between disulfide and lye, it cannot be clearly separated after gravity sedimentation
As a result, the circulating lye carries a large amount of disulfide, which is finally back-extracted into the oil in the extraction system, which is mainly manifested as the total sulfur of the product exceeds the standard
[0006] 3. Cobalt phthalocyanine catalysts are easy to aggregate and deactivate in lye, so catalysts need to be added frequently, and the cost of catalysts is relatively high (about 400,000 to 600,000 yuan / ton), which increases operating costs
However, due to the limitation of operating conditions, the traditional oxidation tower and other mixing equipment can only increase the air injection volume by 5-10 times, and the injection air utilization efficiency is low and it is not easy to operate stably
[0011] Chinese patent CN201110401464.X discloses a method for separating disulfides from lye. In this method, a high-gravity reactor is applied to the removal of disulfides in lye after regeneration, and the disulfides in lye can be removed. The content is reduced to less than 5ppmw. This method does not couple the oxidation of sodium mercaptide with the removal of disulfides, and the process is not optimized enough

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] To regenerate the sulfur-containing alkali liquor containing sodium mercaptide and disulfide, without adding catalyst, the feed temperature of sulfur-containing alkali liquor is 50°C, the oxygen-rich gas with an oxygen content of 50v% is used, and the gas-liquid volume ratio is 100 : 1. When the heat exchange temperature reaches 50°C, it enters the supergravity reactor, the speed of the supergravity machine is 1000 rpm, the operating pressure is normal pressure, and the gas-liquid two-phase is operated in the form of countercurrent. See Table 2 for the comparison of lye properties before and after regeneration.

[0028] Table 2

[0029] Raw lye regenerated lye Sodium mercaptide, wt% 0.1 0.01 Disulfide, ppmw 60 ＜1

Embodiment 2

[0031] Regenerate the sulfur-containing caustic liquor containing sodium mercaptide and disulfide without adding catalyst, the feed temperature of the sulfur-containing caustic liquor is 50°C, the oxygen-rich gas with an oxygen content of 35v% is used, and the gas-liquid specific volume is 100 : 1. When the heat exchange temperature reaches 50°C, it enters the supergravity reactor. The speed of the supergravity machine is 1200 rpm, the operating pressure is normal pressure, and the gas-liquid two-phase is operated in the form of baffle. See Table 3 for the comparison of lye properties before and after regeneration.

[0032] table 3

[0033] Raw lye regenerated lye Sodium mercaptide, wt% 0.05 ＜0.001 Disulfide, ppmw 60 ＜1

Embodiment 3

[0035] Regenerate the sulfur-containing caustic liquor containing sodium mercaptide and disulfide without adding catalyst, the feed temperature of the sulfur-containing caustic liquor is 45°C, the oxygen-enriched gas with an oxygen content of 75v% is used, and the gas-liquid specific volume is 200 : 1. When the heat exchange temperature reaches 45°C, it enters the supergravity reactor. The speed of the supergravity machine is 1200 rpm, the operating pressure is normal pressure, and the gas-liquid two-phase is operated in parallel flow. See Table 4 for the comparison of lye properties before and after regeneration.

[0036] Table 4

[0037] Raw lye regenerated lye Sodium mercaptide, wt% 0.01 ＜0.001 Disulfide, ppmw 60 ＜1

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Abstract

The invention provides an oxidation regeneration method of an alkali liquid containing low concentration sodium mercaptide. The content of sodium mercaptide in the sodium mercaptide-containing alkali liquid is not more than 0.1 wt%. The method comprises the following steps: the alkali liquid and oxygen-rich air respectively enter a hypergravity reactor and undergo a reaction; the sodium mercaptide is oxidized without a catalyst to generate disulfide, and at least a part of the disulfide volatilizes into tail gas; and the regenerated alkali liquid and the tail gas flow carrying gaseous disulfide respectively leave the hypergravity reactor. The method adopts the hypergravity reactor to replace a traditional oxidation tower, so the deep oxidation of the sodium mercaptide is realized; the oxygen-rich air with the oxygen volume percentage being not less than 35% is used as an oxidant, so the oxidation rate is further improved; cobalt phthalocyanine catalysts are not added, so the catalyst cost is saved; and a large air / liquid ratio under a stable state condition is adopted to realize effective separation of the disulfide and the alkali liquid, so the disulfide separation process is omitted, and almost no waste alkali liquid is not generated in the process.

Description

technical field [0001] The invention relates to a method for regeneration of lye, in particular to a method for oxidative regeneration of lye containing sodium mercaptide and disulfide. Background technique [0002] Mercaptan is a kind of sulfide with special odor, which mostly exists in liquefied petroleum gas and other light oil products. As an oxidation initiator, mercaptan can accelerate the oxidation of oil to form colloid, which will reduce the quality and stability of oil. In addition, mercaptans also affect the susceptibility of oil products to additives such as antioxidants and antiknock agents. For the removal of mercaptans in light oil products, the lye extraction and mercaptan removal process is generally used in the industry at present. Countercurrent contact in the extraction tower, the mercaptan reacts with sodium hydroxide to form sodium mercaptide and transfers it to the lye; the lye containing sodium mercaptide enters the oxidation system, and the sodium ...

Claims

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Application Information

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IPC IPC(8): C10G19/08
CPCC10G19/08C10G2300/202C10G2300/44
Inventor 李玮胡雪生高飞魏治中缪西平朱根荣聂普选王苑董卫刚
Owner PETROCHINA CO LTD
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