CN110819378B

CN110819378B - Method for removing organic sulfur in liquid hydrocarbon

Info

Publication number: CN110819378B
Application number: CN201911185893.0A
Authority: CN
Inventors: 吕刚; 王湧舸; 吕金昌
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-11-27
Filing date: 2019-11-27
Publication date: 2021-09-14
Anticipated expiration: 2039-11-27
Also published as: CN110819378A

Abstract

The invention provides a method for removing organic sulfur in liquid hydrocarbon, which is characterized by comprising the following steps: sending sulfur-containing liquid hydrocarbon and anhydrous desulfurizer into a mixer, fully mixing and extracting, sending into a settling tank, taking out the liquid hydrocarbon from which organic sulfide is removed from the top, and obtaining the desulfurizer containing mercaptan from the bottom; the desulfurizer is obtained by dissolving and dispersing sodium mercaptan into an organic solvent, wherein the mass content of the sodium mercaptan is 5-40%; the desulfurizing agent is 1-10 times of the mass content of sulfur in the hydrocarbon liquid. The invention thoroughly solves the problem that the prior liquid hydrocarbon organosulfur removal process can not avoid the generation of alkaline residue, and the desulfurized sulfur-containing substances can also be used as raw material wastes for pesticide production. The method has the advantages of simple equipment, little investment, extremely low consumption of the desulfurizer, simple and easily obtained raw materials, low price, low desulfurization cost, simple operation, environmental protection and easy popularization.

Description

Method for removing organic sulfur in liquid hydrocarbon

Technical Field

The invention relates to a method for removing organic sulfides in petroleum and coal naphtha, light hydrocarbon, four-carbon fraction, condensate oil, natural gas and other liquid hydrocarbons.

Background

With the exploitation of new oil and gas fields and the high-speed development of coal chemical industry, many light oil and gas byproducts are more and more, such as: condensate oil, naphtha, light hydrocarbon, various liquid hydrocarbons containing four carbon and five carbon, natural gas and the like, wherein the light oil gas can be used as raw materials of devices such as crude benzene, ethylbenzene, mixed xylene, civil gas and the like, but the organic sulfur content is as high as 3000ppm to 2 ten thousand ppm, the odor is very large, the environment is seriously influenced during loading and unloading, and the hydrogenation cost is very high.

In the refining process of petroleum, the refining process of light oil containing mercaptan is called deodorization, i.e. the mercaptan with larger hazard in the oil is oxidized into disulfide with smaller hazard by a chemical method.

At present, the mercaptan removal process for liquefied petroleum gas mostly adopts alkaline extraction, adopts catalyst-containing caustic soda alkali liquor to remove mercaptan through an extraction tower, and the alkali liquor after removal is regenerated by air oxidation and separated out disulfide for recycling; the light oil sweetening process mostly adopts alkaline extraction or oxidation deodorization. The method has the defects of incomplete mercaptan removal, high total sulfur of products, low utilization efficiency of alkali liquor, large discharge amount of alkali residues and the like.

The method for removing mercaptan from liquefied petroleum gas/natural gas was originally proposed by the American ring oil product company (UOP) in 1958, and developed to the present time to form a mature liquid-liquid extraction and oxidation regeneration process, namely a Merox method. The most basic process of the process is that after the sodium hydroxide solution dissolves poly-cobalt phthalocyanine or sulfonated cobalt phthalocyanine catalyst, the catalyst is fully mixed and reacted with distillate oil and liquefied petroleum gas/natural gas in a tower or a container, harmful mercaptan in the liquefied petroleum gas/natural gas reacts with the sodium hydroxide to be oxidized into disulfide-sodium mercaptan with less harm to enter alkali liquor, thereby playing a role of deodorization. The Merox catalytic oxidation process is divided into a liquid-liquid method and a fixed bed method. The liquid-liquid deodorization is carried out by contacting the distillate oil containing mercaptan with sodium hydroxide lye containing catalyst (for example, in counter-current or concurrent flow mode), oxidizing mercaptan in the oil into disulfide by air at oil-alkali interface, and recycling the catalyst lye. The content of sodium hydroxide in the alkali liquor is about 10 percent, and when the content of the sodium hydroxide is less than 7 percent, the sodium hydroxide is discharged as waste alkali liquor, so that the alkali consumption is high, and the waste alkali liquor is polluted. For the difficult oxidation of mercaptan, it is generally more effective to use fixed bed method, usually phthalocyanine metal catalyst is loaded on the carrier such as active carbon or silica gel, alkali liquor is continuously or intermittently injected into the bed layer, so that the catalyst is always kept wet by alkali liquor, and air and raw oil are mixed and fed into the fixed bed for deodorization, as shown in US 2988500. In recent patent literature, such as US4124494 and US4159964, the use of quaternary ammonium additives in the preparation of catalyst compositions has also been proposed, however, these processes all use certain amounts of inorganic base (sodium hydroxide) reagents. In the deodorization process, a certain amount of waste alkali liquor is discharged, and a large amount of inorganic alkali is consumed.

The Merox method has obvious disadvantages: 1. mercaptan is weakly acidic, and has low solubility in water because hydrogen bonds cannot be formed, and can be incompletely removed when alkali liquor is contacted for a short time, so that the sulfur content of liquefied gas exceeds the standard; the speed of oxidizing the sodium mercaptide into the disulfide is slow, and the sodium mercaptide which is not oxidized is repeatedly accumulated in a circulating system, so that the efficiency of the alkali liquor is greatly reduced, namely the content of the mercaptan in the fed material is increased, the vicious circulation causes poor mercaptan removal effect, the alkali liquor is frequently replaced, the discharge amount of the alkali residues is large, the cost is increased, and the environment is polluted. In addition, the method has the advantages of long flow, complex device, high investment, large amount of waste liquid, alkaline residue and waste gas generated in the generation process, and poor economic benefit because the removed sulfur finally generates sulfur with low added value. In particular, it is not suitable for removing high-content mercaptan, and it cannot remove carbonyl sulfide with high concentration. The product quality of liquefied gas or natural gas is greatly influenced by the dissolution condition of mercaptan in alkali liquor, the catalytic oxidation of thiolate in an oxidation tower and the separation efficiency of disulfide and catalyst alkali liquor, and the product is unqualified because the total sulfur in the liquefied gas or natural gas product exceeds the standard in actual production, so that the alkali liquor and/or the catalyst alkali liquor has to be recycled or frequently replaced, chemical raw materials are wasted, more alkali residues are generated, and redundant air carries disulfide to form tail gas which is sent into an incinerator for incineration treatment. The consumption of alkali liquor and catalyst in the process is large, and the discharge treatment of waste alkali liquor not only has complex process and high cost, but also can cause secondary pollution, and is a main pollution source of the stink of refineries.

Another common process is the alkali-free sweetening process, which uses an oxidant to catalytically oxidize sodium mercaptide to higher boiling disulfides, and cuts the sulfur-containing components into the heavy oil component by fractional distillation. Such as: OCT-MC process. The process has the advantages of large investment, large energy consumption, serious entrainment loss of oil and gas in tail gas, deteriorated heavy oil processing conditions, incomplete light oil sweetening, poor economic benefit, more alkali waste residue discharge and incapability of avoiding the problems. The desulfurization process can not remove the carbonyl sulfide, so the carbonyl sulfide needs to be removed independently, the existing process for removing the carbonyl sulfide can only treat materials with the carbonyl sulfide content of less than 100ppm generally, and the liquid hydrocarbon with the carbonyl sulfide content of 800ppm produced by a coking device can not be used.

CN01115579.5 discloses a preparation for removing thiol compounds from light oil or liquefied petroleum gas and a removal process thereof, wherein a mixed preparation of inorganic strong base sodium hydroxide, organic amine or alcohol amine, a catalyst and water is used for removing thiol from liquefied gas and gasoline, the concentration of the sodium hydroxide is preferably higher than 35%, the thiol salt generated by the reaction is easy to crystallize, and the pressure drop of the system is large; the mercaptan removal catalyst has poor alkali solubility in high-concentration alkali liquor, is volatile and active, needs to be supplemented periodically, and has high catalyst cost; the high-concentration alkali liquor is easy to generate alkali brittleness during oxidation and regeneration, so that equipment corrosion is caused.

CN201010562902.6 discloses a sweetening agent composition, which adopts a mixture of quaternary ammonium base, organic amine and water to carry out liquefied gas sweetening, does not use inorganic base sodium hydroxide, and has no discharge of alkali residue, but the cost of organic reagents such as quaternary ammonium base, organic amine and the like is higher than that of the prior process for sweetening agent base; the organic reagent has the property of a surfactant, and is easy to be carried into liquefied petroleum gas and gasoline in the mercaptan removal process, so that the quality of oil products is influenced.

CN105797564A discloses a liquefied gas desulfurization method, which is characterized in that a coked liquefied gas qualified by alkali washing and a solvent are fully mixed by a static mixer, and after a primary extraction reaction is completed, the coked liquefied gas enters a primary settling tank for settling separation, and the liquefied gas and a regenerated lean solvent pumped by a lean solvent pump enter a secondary reaction static mixer for full contact, so as to perform a secondary extraction sweetening reaction, and the process is very complex.

CN101705108A discloses "a technology for removing mercaptans from liquid hydrocarbons capable of deeply removing total sulfur", which adopts a reverse extraction technology, i.e. another solvent is used to reversely extract disulfides in the regenerated agent alkali into the solvent. The technology does not solve the problem of discharging the alkali liquor.

CN101358145A discloses an extracting agent for removing sulfides in carbon nine fuel oil and a removing method, the carbon nine fuel oil and the extracting agent are configured according to the mass fraction ratio of 2: 1-1: 2, the extraction temperature is 20-70 ℃, the extraction time is 10-60 minutes, the constant temperature standing time is 20-40 minutes, and after extraction, the carbon nine fuel oil phase is washed by water to wash out the solvent, so that the desulfurized fuel oil is obtained. The extractant comprises single-component solvent or two-component mixed solvent or three-component mixed solvent of N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, triethylene glycol, diethylene glycol, acetonitrile, methanol, ethanol or water. The scheme has large dosage of the extracting agent.

CN105176570A discloses an ionic liquid-based oxidative extraction desulfurization method, which comprises the following steps: mixing oil containing sulfide, ionic liquid and oxidant for reaction; wherein, the sulfide in the oil product containing sulfide is aromatic sulfide and aliphatic sulfide; the cation in the ionic liquid comprises imidazole cation shown as a formula I and/or a formula II; the anion in the ionic liquid is chloride ion, hydrogen sulfate ion or hydrogen phosphate ion. Although the proposal thoroughly solves the problem of alkali liquor discharge, the ionic liquid has higher cost.

CN1347966A discloses an alkali-free refining method of liquefied petroleum gas or natural gas, which comprises, under the condition of completely alkali-free, using a desulfurizing agent and a catalyst to perform fine desulfurization and deodorization treatment on the liquefied petroleum gas or natural gas, so as to remove hydrogen sulfide in the liquefied petroleum gas or natural gas and convert mercaptan into disulfide, and then obtaining the qualified liquefied petroleum gas or natural gas product through fractionation treatment. The fine desulfurization step adopts a desulfurizer which takes iron-calcium oxide as an effective component, and the active component of the catalyst adopted in the deodorization step is selected from one of nano-scale transition metal element oxide, perovskite type rare earth composite oxide and spinel type oxide.

The liquefied gas fraction in petroleum refining contains high content of organic sulfur, and the liquefied gas produced by coking equipment contains about 2 ten thousand ppm of organic sulfur, so that a simple, high-efficiency and deep method for removing high-concentration organic sulfide is required to be developed.

Disclosure of Invention

The invention aims to provide a process method for removing non-thiophene sulfur in light oil gas such as petroleum and coal naphtha, condensate oil, light hydrocarbon, carbon four-fraction and the like, and realize the discharge of three wastes such as alkali residue and the like.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a method for removing organic sulfur in liquid hydrocarbon is characterized by comprising the following steps:

sending the sulfur-containing liquid hydrocarbon and the desulfurizer into a mixer, fully mixing and extracting, sending into a settling tank, taking out the liquid hydrocarbon from which the organic sulfide is removed from the top, and obtaining the desulfurizer containing mercaptan from the bottom; the desulfurizer is obtained by dissolving and dispersing sodium mercaptide into an organic solvent, wherein the water content in the desulfurizer is limited to be below 0.5 mass percent, and the mass content of the sodium mercaptide is 5-40 percent; the desulfurizing agent is 1-10 times of the mass content of sulfur in the liquid hydrocarbon.

The liquid hydrocarbons of the present invention include: petroleum naphtha, coal light hydrocarbon, oil field light hydrocarbon, condensate oil, carbon five, carbon four, natural gas and various light oil gases obtained by other methods. When the desulfurizer of the invention is used, liquid hydrocarbon is preferably subjected to dehydration, the water content is below 0.2 mass percent, preferably below 0.1 mass percent, so that the desulfurization extraction process is performed in a nearly anhydrous state as much as possible, otherwise the recycling frequency of the desulfurizer is influenced. In the present invention, the sodium mercaptide in the desulfurizing agent is preferably one or more of sodium mercaptide and sodium ethiolate, the organic solvent preferably contains organic alcohol, preferably the organic alcohol is monohydric alcohol and/or dihydric alcohol, and the organic alcohol particularly recommended in the present invention is: the solvent may also contain one or more of methanol, ethanol, butanol, octanol and glycol, and the solvent preferably contains one or more of ethylene glycol butyl ether and propylene glycol butyl ether.

The desulfurizer of the invention contains sodium mercaptide, and the solvent also has nonpolar alkyl chain and polar part with structure similar to that of the mercaptide, according to the principle of similar intermiscibility, the desulfurizer can be fully miscible with the mercaptide in the liquid hydrocarbon, thereby extracting the mercaptide from the liquid hydrocarbon into the desulfurizer, and simultaneously removing carbonyl sulfide in the liquid hydrocarbon because the process of removing the mercaptide does not need oxidation reaction and is an extraction process.

The desulfurizing agent recommended by the invention at least comprises the following components: the content of the sodium mercaptan is 5-40%, the content of the organic alcohol is 60-95%, and the content of the alcohol ether is 0-20%.

The desulfurizer containing mercaptan is obtained from the bottom of the settling tank, and can also be used as the desulfurizer to return to the mixer to be mixed with hydrocarbon liquid and be settled for recycling. The desulfurizer can be repeatedly applied for 5-10 times, so that the desulfurization cost is further reduced, but the concentration of the mercaptan in the desulfurizer is increased along with the increase of the cycle number, and the desulfurization capability is reduced after the complexation saturation is reached.

When the desulfurizer containing mercaptan obtained from the bottom of the settling tank is not recycled, the sodium methyl mercaptide and the sodium ethyl mercaptide separated by treating the desulfurizer are good pesticide raw materials.

The mixer of the invention can be a pipeline type various static mixers, and can also be various reaction kettles with stirring, and the like. The invention is not particularly required.

The invention also does not specially limit the type of the settling tank, the fully mixed desulfurizer and the liquid hydrocarbon settle in the settling tank, and the liquid hydrocarbon can remove the non-thiophene organic sulfide in the liquid hydrocarbon after the settlement is separated naturally or by a fiber membrane settler and similar equipment.

The organic sulfides of the present invention include: thiols, carbonyl sulfides, thioethers, and the like.

The invention can also adopt a multi-stage extraction mode with more than two stages.

The inventor finds that in order to remove organic sulfur such as mercaptan from a hydrocarbon liquid by using a high-efficiency desulfurizing agent, the desulfurizing agent needs to be tightly combined with the mercaptan and completely separated from the hydrocarbon liquid, and the organic sulfur can be separated from the hydrocarbon liquid by an extraction method based on the characteristic that the organic sulfur contains lone pair electrons and can form a complex. Alternatively, a solvent which is more soluble in sulfides and is immiscible with the hydrocarbon liquid may be used to transfer the organic sulfur from the hydrocarbon liquid to the solvent.

The inventor researches to find that sodium mercaptide has some unique properties, firstly, the sodium mercaptide can be dissolved in organic solvents such as alcohol or alcohol ether to form a more alkaline solution, and 2, the sodium mercaptide has the property of deep complexing with polar solvents, for example, the sodium mercaptide can absorb the same weight of water to form stable crystals. And methyl mercaptan and ethyl mercaptan have the same polarity and can be complexed with sodium mercaptan to generate a stable complex. And the methyl mercaptan and the ethanethiol also have polarity, can be complexed with sodium mercaptan to generate stable complexes, and can be deeply absorbed by the sodium mercaptan, and because the complexation of water and the sodium mercaptan is preferred to the complexation of the methyl mercaptan and the ethanethiol, the presence of water molecules can preferentially occupy the complexing positions, so that the desulfurization effect is reduced. Therefore, the water content in the desulfurization process of the invention is required to be reduced as much as possible, and the water content of the system is generally required to be less than 0.1 percent.

The mechanism of the complexation is CH₃SNa+(CH₃SH)_n＝CH₃SNa-(CH₃SH)_n n＝1-3，

Research shows that the complexation reaction is fast and the reaction is complete when n is 1.

When n is 2 or 3, the reaction rate is high, the reaction is incomplete, and mercaptan remains.

The solubility of organic sulfur such as mercaptan, carbonyl sulfide, thioether and the like in a desulfurizing agent system consisting of the sodium mercaptan organic solution is far higher than that of liquid hydrocarbon, and experiments show that the solubility of the organic sulfur in an alcoholic solution (particularly an ethanol solution) of 5% sodium mercaptan (particularly sodium methyl mercaptan) is different from that of the liquid hydrocarbon by 1700: 1, after contacting with the desulfurizer, the organic sulfur can be rapidly dissolved and extracted into a desulfurizer system, and theoretically, the extraction removal rate can reach 99%.

The invention dissolves sodium mercaptide in alcohol and alcohol ether to form a solution, wherein the dissolved sodium mercaptide and mercaptan can further form a complex, the alcohol and the alcohol ether are easier to be fully mixed with hydrocarbon liquid than water and are insoluble in the hydrocarbon liquid, and the solution can well play a role of two-phase mass transfer. The use of alcohol ether solvent also prevents the extraction agent from emulsifying when mixed with the hydrocarbon liquid, which is beneficial to phase separation.

A large number of experiments show that the solution is a good desulfurizer for removing methyl mercaptan, ethanethiol, carbonyl sulfide and thioether in liquid hydrocarbon, and can deeply remove organic sulfur in the liquid hydrocarbon.

The desulfurizer has the advantages that the content of mercaptan in liquid hydrocarbon, such as liquefied gas, is dominant, the content of mercaptan accounts for 99 percent of the total amount of removed organic sulfur, the content of other sulfur is low, the desulfurizer only contains sodium mercaptan and a solvent from the beginning, and after the desulfurizer is repeatedly used for many times, the desulfurizer forms a mercaptan-rich solution system after the desulfurization of the liquid hydrocarbon is completed, the system is a good raw material for pesticide production, namely, the final recovered material of the desulfurizer can be utilized, no solid waste is discharged, and the problem that the prior liquid hydrocarbon organic sulfur removal process can not avoid the generation of caustic sludge is thoroughly solved. The whole desulfurization process has no discharge of waste water and waste gas.

The desulfurizer reclaimed material contains no water, is rich in mercaptan, has certain viscosity, does not crystallize at room temperature, can be conveyed to a user manufacturer in a high-concentration mode, is convenient for the user to use, and reduces the storage and transportation cost of the sodium mercaptide. The said product can produce high concentration sodium mercaptide solid, and this makes it possible for user to develop high quality product and raise economic benefit.

The method can deeply remove the high-content organic sulfur to be less than 10ppm, so that the organic sulfur in the materials is recycled, no alkali residue, waste water and waste gas are discharged in the desulfurization process, the hydrogenation consumption of the subsequent oil product deep processing procedure can be greatly reduced, the quality of the propylene produced in the petroleum refining process can be improved, the carbon four-fraction is changed into the ultra-low sulfur raw material, and the method has great significance for the deep processing.

The invention has the advantages that: the desulfurizing agent used in the method has strong complexing extraction effect on organic sulfur, can completely transfer mercaptan and carbonyl sulfur in liquid hydrocarbon into the desulfurizing agent to generate organic sulfide complex salt, and the product can be dispersed in a heavier solvent of the desulfurizing agent and separated from hydrocarbon liquid through natural sedimentation or fiber membrane sedimentation. The mixture only has an extraction effect on the sulfide, so that most of sulfide sulfides can be separated from hydrocarbon liquid after being extracted and settled.

The process of the invention does not produce waste residue, waste liquid and waste gas, the recovery material of the desulfurizer which completely completes the desulfurization mission is rich in sodium mercaptan, and only contains trace amount of thioether and other impurities can be directly used for pesticide production or used for producing sulfide with higher added value after simple treatment. The device has the advantages of simple equipment, less investment, extremely low consumption of the desulfurizer, simple and easily obtained raw materials, low price, low desulfurization cost and simple operation. The method fundamentally changes the industrial method of removing non-thiophenic sulfur by using the process of sulfonated titanium, cobalt, cyanide and alkali washing and the like, so that the hydrogenation consumption of light oil gas produced by various channels is greatly reduced, and the coking liquefied gas can realize deep desulfurization. The alkali washing method can only obtain sulfur with low added value, and has poor economic benefit, and the method obtains sodium mercaptide with high added value. The method can also remove most of the chlorine in the oil gas at the same time, reduces the damage to the catalyst during hydrogenation, and has great influence on the environmental protection and low-cost production of the coal chemical industry and the petrochemical industry.

Detailed Description

The analysis and detection method comprises the following steps:

the contents of the organic sulfur, including mercaptan, carbonyl sulfide and thioether, are analyzed and detected by gas chromatography.

Example 1

A desulfurizing agent containing 15% of sodium methyl mercaptide and 5% of sodium ethyl mercaptide is used, an organic solvent of the desulfurizing agent is methanol, the desulfurizing agent and catalytic liquefied gas containing 500ppm of methyl mercaptan and 120ppm of carbonyl sulfur are mixed in a pipeline through a mixer according to the ratio of agent sulfur to 3, the mixture and the catalytic liquefied gas enter a settling tank for settling separation for 2 hours, the desulfurized liquefied gas is taken to be subjected to gas chromatography detection, the content of the methyl mercaptan in the liquefied gas is reduced to 6ppm, and the content of the carbonyl sulfur in the liquefied gas is reduced to 0.45 ppm. The desulfurizer settled to the bottom of the tank only contains trace free methyl mercaptan, which proves that the methyl mercaptan in the liquefied gas is mostly complexed by the desulfurizer, and the desulfurizer still has desulfurization activity and can be recycled.

Example 2

A methanol solution containing 10% of sodium methyl mercaptide, 10% of sodium ethanethiol and 2% of ethylene glycol monobutyl ether is used as a desulfurizer, the desulfurizer is quantitatively injected into liquefied gas in a pipeline for conveying the coking liquefied gas at a flow rate of 5% of agent sulfur ratio, the liquefied gas is fully mixed with the coking liquefied gas through a static mixer, and the mixture enters a fiber membrane settler to realize the removal of organic sulfur in a settling tank. The coking liquefied gas containing 5700ppm of methyl mercaptan, 860ppm of ethanethiol, 220ppm of carbonyl sulfide and 12ppm of thioether is removed by two-stage extraction, and the content of the sulfur after removal is detected by gas chromatographic analysis, wherein the total content of the mercaptan is reduced to 4ppm, the content of the carbonyl sulfide is 0.63ppm, and the total content of the thioether is 5 ppm.

The settled desulfurizer is continuously recycled.

Example 3

The desulfurizer containing 15% of sodium methyl mercaptide, 15% of sodium ethyl mercaptide, 4% of ethylene glycol butyl ether, 50% of octanol and 16% of butanol is mixed with liquefied gas containing high-concentration organic sulfur, wherein the liquefied gas contains 21000ppm of total mercaptans, 530ppm of carbonyl sulfur and 83ppm of total sulfides, the desulfurizer is mixed with the liquefied gas in a pipeline according to a sulfur ratio of 6, the mixture is separated in a settling tank through a fiber membrane settler, after primary desulfurization, the total sulfur removal rate is 98.7%, the desulfurizer is recycled after being separated and is used for removing the same raw materials, and after 7 th desulfurization, the total sulfur removal rate is 68%. The cos content of this residue was still reduced to 7ppm at the 7 th pass.

Table 1 the results of the tests after the desulfurization agents were recycled for the same liquefied gas feedstock: (ppm)

The desulfurization effect of the desulfurizer is obviously reduced after seven times of desulfurization, the complexation reaction is saturated, and the desulfurizer is not used any more as a desulfurizer and is treated as a desulfurizer reclaimed material.

Example 4

200ml of desulfurizer containing 10% of sodium methyl mercaptide, 5% of sodium ethyl mercaptide, 73% of methanol and 2% of ethylene glycol monobutyl ether is taken to be mixed with 500ml of FCC gasoline containing 386ppm of total sulfur in a 1000ml container by shaking for 10 minutes, and then the mixture is kept still for 2 hours. And taking the upper gasoline and detecting the sulfur content by using gas chromatography.

TABLE 2 FCC gasoline desulfurization results

Example 4	Hydrogen sulfide	Methyl mercaptan	Ethanethiol	Thioethers	Thiophene(s)
						FCC gasoline as raw material	2ppm	78ppm	106ppm	34ppm	172ppm
Post-dehydrated FCC gasoline	0	0.6ppm	0.9ppm	4ppm	69ppm

From the analysis results, the desulfurizing agent has obvious effect on removing active mercaptan and has general effect on inert thiosulfide and thiophene.

Example 5

20ml of desulfurizer containing 10% of sodium methyl mercaptide and 8% of sodium ethyl mercaptide is taken and mixed in 1 liter of glass bottle filled in 800ml of south Pase condensate oil, the mixture is shaken for 10 minutes, and is kept stand for 2 hours, and the condensate oil is taken to detect the content of mercaptan in the condensate oil. The results are as follows.

TABLE 3 condensate deodorization test results

Example 5	Hydrogen sulfide	Methyl mercaptan	Ethanethiol
				Before taking off	120ppm	1200ppm	540ppm
After taking off	0	0.32ppm	0.44ppm

The south Pase condensate treated by the desulfurizer has no odor, and the environmental protection problem in the storage and transportation process is solved.

Example 6

And (2) adding 10ml of a desulfurizing agent containing 5% of sodium methyl mercaptide and 2% of sodium ethyl mercaptide into 1000ml of No. 120 solvent oil obtained by distilling condensate oil, shaking and mixing for 10 minutes, standing and layering for 2 hours, and measuring the content of mercaptan in the No. 120 solvent oil. The feed containing 34ppm of mercaptan was desulfurized and no mercaptan was detected. It can be seen that the deodorizing effect of the desulfurizing agent on the solvent oil is obvious.

Comparative example 1

The same procedure as in example 2 was repeated except that N-methyldiethanolamine was used in place of the 10% sodium methyl mercaptide and the 10% sodium ethyl mercaptide of example 2. The desulfurization was carried out by contacting the coking liquefied gas in countercurrent with the desulfurization raw material in the same manner as in example 2 in an extraction column at 50 ℃.

TABLE 4 comparison of desulfurization effect using different desulfurizing agents

Comparative example 2

The same desulfurization agent as used in example 5 was added in the same amount, and the same batch of south pars condensate which was not dehydrated with anhydrous calcium chloride was subjected to desulfurization test (water content of the condensate measured by a moisture meter was 0.8%). After mixing, standing and desulfurizing, the desulfurizing effect is as follows.

TABLE 5 Water content test results of desulfurization system during deodorization of condensate oil

	Hydrogen sulfide	Methyl mercaptan	Ethanethiol
				Raw material before threshing	120ppm	1200ppm	540ppm
Comparative example 2 after dehydration (raw material water)	0	85ppm	32ppm
				Example 5 after dehydration (anhydrous starting material)	0	0.32ppm	0.44ppm

It can be seen that the water content in the system has an influence on the desulfurization effect of the desulfurizing agent.

Claims

1. A method for removing organic sulfur in liquid hydrocarbon is characterized by comprising the following steps: sending sulfur-containing liquid hydrocarbon and anhydrous desulfurizer into a mixer, fully mixing and extracting, sending into a settling tank, taking out the liquid hydrocarbon from which organic sulfide is removed from the top, and obtaining the desulfurizer containing mercaptan from the bottom; the desulfurizer is obtained by dissolving and dispersing sodium mercaptide into an organic solvent, wherein the water in the desulfurizer is limited to be less than 0.5 mass percent, and the mass content of the sodium mercaptide is 5-40 percent; the desulfurizing agent is 1-10 times of the mass content of sulfur in the hydrocarbon liquid; the organic solvent contains a nonpolar alkyl chain and a polar part which have similar structures with the mercaptan, and the desulfurizer can be fully dissolved with the mercaptan in the liquid hydrocarbon according to the similar intermiscibility principle, so that the mercaptan is extracted from the liquid hydrocarbon into the desulfurizer.

2. The method for removing organic sulfur from liquid hydrocarbon according to claim 1, wherein the liquid hydrocarbon comprises: petroleum naphtha, coal light hydrocarbon, oil field light hydrocarbon, condensate oil, carbon five, carbon four, natural gas and various light oil gases obtained by other methods.

3. The method of claim 1, wherein the organic solvent of the desulfurizing agent contains organic alcohol.

4. The method of claim 3, wherein the organic alcohol is a monohydric alcohol and/or a dihydric alcohol.

5. The method of claim 1, wherein the desulfurizing agent comprises an alcohol ether.

6. The method for removing organic sulfur in liquid hydrocarbon according to claim 4, wherein the alcohol ether in the desulfurizing agent is one or more of ethylene glycol butyl ether and propylene glycol butyl ether.

7. The method for removing organic sulfur in liquid hydrocarbon according to claim 3, 4, 5 or 6, wherein the desulfurizing agent composition at least comprises: the content of the sodium mercaptan is 5-40%, the content of the organic alcohol is 60-95%, and the content of the alcohol ether is 0-20%.

8. The method of claim 1, wherein the sodium mercaptide in the desulfurizing agent is one or more of sodium mercaptide and sodium ethanemercaptide.

9. The method of claim 3, wherein the organic alcohol is one or more of methanol, ethanol, butanol, octanol and ethylene glycol.

10. The method for removing organic sulfur in liquid hydrocarbon according to claim 1, wherein the desulfurizing agent containing mercaptan is obtained from the bottom of the settling tank and returned to the mixer for recycling.