CN103740407A - Alkali cleaning-extraction-washing-hydrogenation combined process for producing low-sulfur-content gasoline - Google Patents

Abstract

A method for producing low-sulfur gasoline. The raw material of gasoline is cut into light and heavy fractions; the light fractions are refined and demercapted by alkali and then enter the extraction tower to extract and remove thiophenes, sulfides, and disulfide-like sulfides to obtain alkali-washed-extracted light fractions. Gasoline fraction and extraction phase; among them, the alkali washing-extraction light gasoline fraction is washed to obtain the alkali washing-extraction-washing light gasoline fraction, and the sulfur-containing light gasoline fraction recovered from the extraction phase is mixed with the heavy gasoline fraction for selective addition. Hydrogen desulfurization, to obtain hydrogenated heavy gasoline fractions, and mix alkali washing-extraction-washing light gasoline fractions with hydrogenated heavy gasoline fractions to obtain gasoline products. The method can produce gasoline with a sulfur content lower than 50 ug/g and meeting the National IV standard, and can also produce gasoline with a sulfur content lower than 10 ug/g and meeting the National V standard.

Description

A combination process of alkali washing-extraction-washing-hydrogenation for producing low-sulfur gasoline

technical field

The invention relates to a method for reducing the sulfur content of gasoline, in particular to a method for reducing the sulfur content of catalytic cracking gasoline and producing ultra-low sulfur gasoline.

Background technique

With the enhancement of human environmental protection awareness, people pay more and more attention to the pollution of atmospheric environment caused by harmful substances in automobile exhaust. Countries all over the world have put forward increasingly strict requirements on the composition of engine fuel, especially the sulfur content. The European Union began to implement the Euro IV vehicle exhaust emission standard in 2005, requiring the sulfur content of gasoline to be less than 50ug/g. On September 1, 2009, the European Union began to implement the Euro V emission standard, requiring the sulfur content of gasoline to be less than 10ug/g. It is also planned to be implemented in 2014 The more stringent Euro VI standard is implemented; China implemented the National III gasoline standard (GB17930-2006) at the end of 2009, requiring the sulfur content not to exceed 150ug/g; it is planned to fully implement the National IV gasoline standard from January 1, 2014. The sulfur content is required to be no more than 50ug/g; the National V gasoline standard will be fully implemented from January 1, 2018, and the sulfur content is required to be no more than 10ug/g. The continuous upgrading of gasoline quality standards has made the gasoline production technology of refineries face more and more severe challenges.

At present, more than 90% of the sulfur in domestic finished gasoline comes from catalytic cracking (FCC) gasoline, so reducing the sulfur content of FCC gasoline is the key to reducing the sulfur content of finished gasoline.

There are usually two ways to reduce the sulfur content of FCC gasoline: FCC feedstock hydrotreating (pre-hydrogenation) and FCC gasoline hydrodesulfurization (post-hydrogenation). Among them, the pretreatment of catalytic cracking raw materials can greatly reduce the sulfur content of catalytic cracking gasoline, but it needs to be operated under very harsh conditions of temperature and pressure. At the same time, because of the large processing capacity of the device, the hydrogen consumption is also relatively large, all of which will increase the capacity of the device. investment or operating costs. However, due to the heavy crude oil in the world, more and more catalytic cracking units have begun to process inferior raw materials containing atmospheric and vacuum residues, so the number of hydrogenation units for catalytic cracking raw materials is also increasing year by year. At the same time, with the innovation of catalytic cracking technology and the gradual application of catalytic cracking desulfurization additives, the sulfur content of catalytic cracking gasoline of some enterprises in my country can reach below 500ug/g, or even below 150ug/g. But if you want to further reduce the sulfur content of FCC gasoline, make it less than 50ug/g (meet the Euro IV emission standard on gasoline sulfur content limit), or even less than 10ug/g (meet the Euro V emission standard on gasoline sulfur content limit) , then the operating severity of the catalytic cracking raw material hydrogenation unit must be greatly increased, which is very economically uneconomical.

Compared with pre-hydrogenation, FCC gasoline hydrodesulfurization is lower than FCC raw material hydrogenation pretreatment in terms of equipment investment, production cost and hydrogen consumption, and its different desulfurization depths can meet the requirements of different specifications of sulfur content. However, if the traditional hydrofinishing method is used, the olefin components with high octane number in catalytic cracking gasoline will be largely saturated and the octane number will be greatly lost. Therefore, it is imminent to develop a low-sulfur gasoline production technology with low investment and low octane loss.

The olefin content in the light fraction of catalytic cracking gasoline is high, and the olefin content in the heavy fraction is relatively low. Therefore, the fraction cutting method can be used to cut the catalytic cracking gasoline into light fraction and heavy fraction; the heavy fraction adopts traditional hydrodesulfurization technology, and the light fraction Adopt non-hydrogen desulfurization technology. The literature shows that sulfides in catalytic cracking gasoline are mainly divided into three categories: mercaptans, sulfides, and thiophenes: thiophenes have the highest content, accounting for about 70% of sulfides; followed by mercaptans, accounting for 16%~ About 20%; the content of sulfides is relatively less than the other two types. The content of methyl thiophene in thiophene sulfides in gasoline is relatively high, accounting for about 40%, followed by thiophene accounting for about 15%. From the boiling point of sulfide, it can be known that mercaptans in gasoline light components are mainly concentrated below 80°C, while thiophene exists in the fractions of 80°C to 90°C, and the sulfur content is the highest in the range of 100°C to 120°C, accounting for the total About 20% of the sulfur content should be mostly methyl thiophene and a small amount of tetrahydrothiophene. When non-hydrogenation desulfurization technology is used to remove sulfides in gasoline light fractions, the higher the cut point of light and heavy fractions, the less olefin content in heavy fractions, and the smaller the loss of olefins caused by hydrogenation; when the cut point is 80°C When the cut point is 90℃, the thiophene content in the light fraction is relatively high. At this time, thiophene must be removed to make the sulfur content in the light fraction ≯10ug/g. Therefore, the key to non-hydrodesulfurization is to remove thiophene in light fractions.

Contents of the invention

In view of the above situation, the present invention proposes a method for producing low-sulfur gasoline, which cuts gasoline raw materials into light gasoline fractions and heavy gasoline fractions, and adopts hydrogenation and non-hydrogenation combined technology for desulfurization; to solve the problem of high sulfur content in gasoline light fractions , first adopt alkali refining to remove mercaptans; then use extraction technology to remove not only thiophene, but also mercaptans, sulfides, and disulfide-like sulfides; for olefins that mainly exist in light gasoline fractions, use extraction technology Desulfurization avoids the problem of olefin loss in light gasoline fractions caused by hydrogenation; heavy gasoline fractions are desulfurized by conventional hydrofining technology; finally, alkali washing-extraction-washing light gasoline fractions are mixed with hydrogenated heavy gasoline fractions to obtain a sulfur content not greater than 50ug/g or 10ug/g gasoline products. The invention only needs to add an extraction and desulfurization device on the basis of the original hydrogenation device, the device is simple to transform, not only saves investment, but also can ensure a small loss of gasoline octane number, and produce gasoline products with a sulfur content of not more than 50ug/g or 10ug/g.

The method for producing low-sulfur gasoline of the present invention comprises the following steps:

(1). Cut the catalytic cracking gasoline raw material into light gasoline fraction and heavy gasoline fraction, wherein the cutting point of light gasoline fraction and heavy gasoline fraction is 60°C-100°C;

(2). The light gasoline fraction is subjected to alkali refining sweetening to remove mercaptans, hydrogen sulfide and phenolic acidic substances to obtain the alkali-washed light gasoline fraction;

(3). The alkali-washed light gasoline fraction is extracted to remove thiophene, mercaptan, sulfide, and disulfide-like sulfides, so as to obtain the alkali-washed-extracted light gasoline fraction and the extraction phase;

(4). The extraction phase in step (3) enters the heating regenerator, steams the sulfur-containing light gasoline fraction in the extraction phase, and recovers the extraction agent. The regeneration temperature is 80 ° C ~ 110 ° C; the regenerated extraction The sulfur-containing gasoline is hydrodesulfurized together with the heavy gasoline fraction.

(5). In the step (3), the alkali washing-extraction light distillate gasoline is washed, and the extractant dissolved in the oil is removed to obtain the alkali washing-extraction-washing light gasoline fraction;

(6). After the heavy gasoline fraction and the sulfur-containing light gasoline fraction distilled from the extraction phase are mixed, they are contacted with the hydrodesulfurization catalyst together with hydrogen, and the conventional selective hydrodesulfurization reaction is carried out to obtain the hydrogenated heavy gasoline fraction;

(7). The hydrogenated heavy gasoline fraction is mixed with the alkali washing-extraction-washing light gasoline fraction to obtain a gasoline product with a sulfur content≯50ug/g or a gasoline product with a sulfur content≯10ug/g.

Description of drawings

Accompanying drawing 1 is a kind of alkaline cleaning-extraction-washing-hydrogenation combined process flow chart of the present invention for producing low-sulfur gasoline.

In the figure: 1. Gasoline raw material oil pipeline; 2. Fractionation tower; 3. Light gasoline fraction oil pipeline; 4. Heavy gasoline fraction oil pipeline; 5. Pipeline; 6. Pump; 7. Pipeline; 8. Pipeline; 9. Heating furnace ; 10, pipeline; 11, hydrogenation reactor; 12, pipeline; 13, alkali washing refining tower; 14, pipeline; 15, extraction tower; 16, pipeline; 17, pipeline; 18, regenerator; 19, pipeline; 20 , pipeline; 21, separator; 22, pipeline; 23, pipeline; 24, compressor; 25, pipeline; 26, fresh hydrogen delivery pipeline; 27, pipeline; 28, washing device; 29, pipeline; 30, pipeline; 31 , stabilization tower; 32, pipeline; 33, pipeline.

Detailed ways

The process flow of the method for reducing gasoline sulfur content in the present invention is as follows: the gasoline raw material enters the fractionating tower 2 through the pipeline 1 and is cut into light and heavy gasoline fractions, wherein the heavy gasoline fraction is mixed with the sulfur-containing distillate oil from the pipeline 19 through the pipeline 4, and enters through the pipeline 5 Pump 6, after the pressurized heavy gasoline fraction is mixed with the hydrogen from the pipeline 27 through the pipeline 7, it enters the heating furnace 9 through the pipeline 8, and the heated material enters the reactor 11 through the pipeline 10 to contact with the hydrodesulfurization catalyst for hydrogenation The generated oil enters the high-pressure separator 21 through the pipeline 12, the hydrogen-rich gas from the top of the separator 21 enters the compressor 24 through the pipeline 23, and the compressed hydrogen-rich gas enters the pipeline 27 together with the fresh gas from the pipeline 26 through the pipeline 25 , mixed with heavy distillates from line 7. The hydrogenated heavy gasoline fraction from the bottom of separator 21 is mixed with the caustic-extraction-washed light gasoline fraction from line 29 via line 29 to destabilize the column.

The light distillate gasoline enters the alkali washing refining tower 13 through the pipeline 3, the gasoline after the mercaptan is removed through the alkali washing enters the extraction tower 15 through the pipeline 14, and the extraction phase coming out from the bottom of the extraction tower 15 enters the regenerator 18 through the pipeline 17, and is discharged from the regenerator 18 The extractant separated from the bottom enters the top of the extraction tower 15 through the pipeline 20, and the sulfur-containing distillate oil recovered from the top of the regenerator 18 is mixed with the heavy distillate oil from the pipeline 4 through the pipeline 19 and then hydrotreated. The desulfurized light distillate oil that comes out from the top of the extraction tower 15 enters the washing device 28 through the pipeline 16, and the light distillate after washing is mixed with the heavy distillate oil from the pipeline 22 through the pipeline 29, and the gasoline after the mixing enters the stabilizing tower 31 through the pipeline 30, and is separated Obtained light hydrocarbons and gasoline products are drawn out through pipelines 32 and 33 respectively.

The following examples will further illustrate the method provided by the present invention, but do not limit the protection scope of the present invention.

Example 1

Using FCC gasoline A as the raw material, first cut the raw material, the cutting point is 95°C, the heavy gasoline fraction accounts for 52% of the raw material, the gasoline fraction (FCCN), light gasoline fraction (LCN), heavy gasoline fraction (HCN) The properties are shown in Table 1. The light gasoline fraction is demercaptanized by an advanced alkali washing device, and the alkali washing is conventional alkali washing (10% sodium hydroxide aqueous solution). After alkali washing, the mercaptan sulfur content in the light gasoline fraction is reduced to 15.3ug/g; The light gasoline fraction enters the extraction and desulfurization unit to obtain the alkali washing-extraction light gasoline fraction and the extraction phase; the extraction agent is nitrogen-formylmorpholine, the solvent-oil ratio is 2:1, the number of extraction stages is 4, and the extraction temperature is 55°C , to remove thiophene, mercaptan, sulfide, and disulfide-like sulfides in light distillate gasoline; the extract phase enters the heating regenerator, the regeneration temperature is 110°C, and the regenerated extractant is recycled, and the steamed sulfur-containing gasoline is mixed with The heavy gasoline fractions are mixed and sent to the hydrogenation unit; the alkali washing-extraction light gasoline fractions are sent to the washing device, and the detergent is water to remove the extractant in the alkali washing-extraction gasoline fractions; the heavy gasoline fractions are hydrotreated to obtain hydrogenated heavy gasoline fractions.

After the gasoline is treated by the technology of the present invention, the properties of alkali washing-extraction-washing light gasoline fraction (LCN’), hydrogenated heavy gasoline fraction (HCN’) and gasoline product (FCCN’) are shown in Table 1-2.

Table 1-1 Properties of gasoline raw materials and their fractions

Properties of table 1-2 gasoline raw material after process treatment of the present invention

Comparing Table 1-1 and Table 1-2, it can be seen that after the gasoline raw material is treated by the process of the present invention, the sulfur content in the light gasoline fraction is reduced from 220ug/g to 20.1ug/g, that is, the extraction and desulfurization process of the present invention has a higher The desulfurization ability can make the sulfur content of light gasoline fraction below 50ug/g; the sulfur content of heavy gasoline fraction decreases from 1430ug/g to 8.1ug/g; the sulfur content of gasoline decreases from 849ug/g to 13.9ug/g, indicating that the The technology can produce gasoline with a sulfur content lower than 50ug/g and a sulfur content meeting the National IV standard.

Example 2

Using FCC gasoline B as raw material, the light gasoline fraction is demercaptanized by advanced alkali washing equipment, and the alkali washing is conventional alkali washing (10% sodium hydroxide aqueous solution), and the mercaptan sulfur content in gasoline is reduced to 22.5ug/g; The gasoline after alkali washing was cut, and the cut point was 100°C, and the light distillate gasoline was taken to investigate the desulfurization effect of the extractant. The alkali-washed light gasoline fraction enters the extraction and desulfurization unit to obtain the alkali-washed-extracted gasoline fraction and the extraction phase; the extraction agent is sulfolane, the solvent-oil ratio is 3:1, the number of extraction stages is 4, and the extraction temperature is 45°C. Thiophene, mercaptan, sulfide, and disulfide-like sulfides in distillate gasoline; alkali washing-extraction light gasoline fraction enters the washing device, the detergent is ethanol, and the extractant in the refined gasoline fraction is removed to obtain alkali washing-extraction- Washing light gasoline fraction. The results are as follows: the sulfur content of the light fraction of the raw material is 342.6ug/g, and the sulfur content is reduced to 21.1ug/g after alkali washing, extraction and washing, which shows that this process can produce gasoline with a sulfur content lower than 50ug/g and a sulfur content meeting the National IV standard .

Example 3

The gasoline produced by catalytic cracking after hydrotreating coker wax oil was used as the raw material, the gasoline raw material was cut, and the cutting point was 92°C, and the light distillate gasoline was taken to investigate the desulfurization effect of the extractant. The light gasoline fraction is demercaptanized by an advanced alkali washing device, and the alkali washing is conventional alkali washing (10% sodium hydroxide aqueous solution). After alkali washing, the mercaptan sulfur content in the light gasoline fraction is reduced to 4.2ug/g; The light gasoline fraction enters the extraction and desulfurization unit to obtain the alkali washing-extraction light gasoline fraction and the extraction phase. The extraction agent is nitrogen-formylmorpholine, the solvent-oil ratio is 2:1, the number of extraction stages is 4, and the extraction temperature is 38°C , remove thiophene, mercaptan, sulfide, and disulfide sulfides in light distillate gasoline; alkali washing-extracting light gasoline fraction enters the washing device, and the detergent is formamide, removes the extractant in the refined gasoline fraction, and obtains Alkali washing-extraction-washing of light gasoline fractions. The results are as follows: the sulfur content of the raw material light fraction is 19.0ug/g, and the sulfur content is reduced to 8.3ug/g after alkaline washing, extraction and washing. It shows that the inventive process is also effective for gasoline produced by catalytic cracking after hydrotreating wax oil. Gasoline produced by catalytic cracking after hydrotreatment of wax oil is used as raw material, and the sulfur content of light gasoline fraction is low, but it does not meet the requirements of the national V standard gasoline sulfur content. Using this process, gasoline with a sulfur content of less than 10ug/g and a sulfur content meeting the National V standard can be produced.

Example 4

Using FCC gasoline C as the raw material, the raw material was first cut, and the cutting point was 89°C, and the light distillate gasoline was taken to investigate the desulfurization effect of the extractant. The specific method is as follows:

1. Preparation of gasoline

Thiophene was added to the light gasoline fraction to investigate the desulfurization effect of the extractant on gasoline with different sulfur content.

Add 1000ug/g to light distillate gasoline, and record it as sample 1;

Add 500ug/g to light distillate gasoline, and record it as sample 2;

No thiophene is added to light distillate gasoline, which is recorded as sample 3;

2. Take the above-mentioned gasoline to investigate the desulfurization effect of the extractant. The light gasoline fraction is demercaptanized by an advanced alkali washing device, and the alkali washing is conventional alkali washing (10% sodium hydroxide aqueous solution). After alkali washing, the mercaptan sulfur content in the light gasoline fraction is reduced to 18.3ug/g; The light gasoline fraction enters the extraction and desulfurization unit to obtain the alkali washing-extraction light gasoline fraction and the extraction phase. The extraction agent is sulfolane, the solvent-oil ratio is 3:1, the number of extraction stages is 4, and the extraction temperature is 25°C to remove the light fraction. Thiophene, mercaptan, sulfide, and disulfide-like sulfides in gasoline; alkali washing-extraction of light gasoline fraction enters the washing device, the detergent is ethylene glycol, and removes the extractant in the alkali washing-extraction gasoline fraction. The results are shown in Table 4-1

Table 4-1 Sulfur content of each light distillate gasoline after desulfurization

Table 4-1 shows that the extraction desulfurization process in the process of the present invention has a relatively high desulfurization ability, and the desulfurization ability of thiophene is remarkable.

Example 5

Using simulated gasoline as raw material, the effect of demercaptan and dethiophene extraction was mainly investigated.

1. The configuration of simulated gasoline

The content of thiophene in the simulated gasoline prepared in the experiment is about 500ug/g, the content of mercaptan is about 190ug/g, and the total sulfur is 241.57ug/g. The composition of simulated gasoline is shown in Table 5-1

Table 5-1 Composition of Simulated Gasoline

2. Simulate gasoline advanced alkali washing device to remove mercaptans. The alkali washing is conventional alkali washing (10% sodium hydroxide aqueous solution). After alkali washing, the mercaptan sulfur content in the light gasoline fraction is reduced to 115.2ug/g; The washed light gasoline fraction enters the extraction and desulfurization unit to obtain the alkali washing-extracted light gasoline fraction and the extraction phase. Thiophene, mercaptan, sulfide, and disulfide-like sulfides in distillate gasoline; alkali washing-extract the light gasoline fraction into the washing device, and the detergent is glycerol to remove the extractant in the gasoline fraction.

2. After alkali washing, extraction and washing, the results are as follows, the sulfur removal rate reaches 92%, and after desulfurization, the sulfur content of simulated gasoline is 19.32ug/g. It can be seen that the extraction desulfurization process in the process of the present invention has a higher desulfurization capacity, and has a good removal effect on the main sulfides in the light gasoline fraction: thiophene sulfur and mercaptan sulfur, so that the sulfur in the fraction The content reaches the standard of ≯50ug/g.

Example 6

Using FCC gasoline D as the raw material, the light gasoline fraction with a boiling point of 80°C to 100°C was taken to investigate the desulfurization effect of the extractant in the process of the present invention.

The light gasoline fraction is demercaptanized by an advanced alkali washing device, and the alkali washing is conventional alkali washing (10% sodium hydroxide aqueous solution). After alkali washing, the mercaptan sulfur content in the light gasoline fraction is reduced to 24.6ug/g; The light gasoline fraction enters the extraction and desulfurization unit, the extraction agent is nitrogen-formylmorpholine, the solvent-oil ratio is 2:1, the number of extraction stages is 4, and the extraction temperature is 30°C to obtain the alkali washing-extraction light gasoline fraction and the extraction phase ; Remove thiophene, mercaptan, sulfide, and disulfide sulfides in light distillate gasoline; Alkali washing-extracting light gasoline fraction enters the washing device, and the detergent is methyl alcohol, removes the extractant in the refined gasoline fraction, and obtains alkali Wash-extract-wash light gasoline fraction.

The results are as follows: the sulfur content of the light fraction of the raw material is 133.0ug/g, and the sulfur content after extraction and washing is reduced to 19.3ug/g, which shows that the adoption of this process can make the sulfur content of the light gasoline fraction at 80°C to 100°C lower than 50ug/g, The sulfur content standard in gasoline that meets the National IV standard.

Example 7

FCC gasoline E was used as raw material for cutting, and the cutting point was 95°C. Light distillate gasoline was taken to investigate the desulfurization effect of the regenerated extractant.

The extractant is the fresh agent nitrogen nitrogen dimethylformamide (DMF); the light gasoline fraction is demercaptanized by an advanced alkali washing device, and the alkali washing is conventional alkali washing (10% sodium hydroxide aqueous solution). After alkali washing, the light gasoline fraction The content of mercaptan sulfur in the oil is reduced to 16.3ug/g; the alkali-washed light gasoline fraction enters the extraction and desulfurization unit, the extraction agent is nitrogen-nitrogen dimethylformamide (DMF), the ratio of agent to oil is 2:1, and the number of extraction stages is Level 2, the extraction temperature is 30°C, to obtain the alkali washing-extraction light gasoline fraction and the extraction phase; remove thiophene, mercaptan, sulfide, and disulfide-like sulfides in the light fraction gasoline; alkali washing-extraction light gasoline fraction Enter the washing device, the detergent is water, remove the extractant in the refined gasoline fraction, and obtain the alkali washing-extraction-washing light gasoline fraction.

Recover the extractant in 1, and act for 6 hours under the condition of 95° C., and carry out the extraction desulfurization experiment on the recovered extractant. The light gasoline fraction is demercaptanized by an advanced alkali washing device, and the alkali washing is conventional alkali washing (10% sodium hydroxide aqueous solution). After alkali washing, the mercaptan sulfur content in the light gasoline fraction is reduced to 16.3ug/g; The light gasoline fraction enters the extraction and desulfurization unit, the extraction agent is recovered nitrogen nitrogen dimethylformamide (DMF), the solvent-to-oil ratio is 2:1, the number of extraction stages is 2, and the extraction temperature is 30°C to obtain alkali washing-extraction Light gasoline fraction and extraction phase; removal of thiophene, mercaptan, sulfide, and disulfide-like sulfides in light gasoline fractions; alkali washing-extracting light gasoline fractions into a washing device, the detergent is water, and removed from refined gasoline fractions The extractant is used to obtain the alkali washing-extraction-washing light gasoline fraction.

The results are as follows: the desulfurization rate of the fresh extractant is 67.2%, and the desulfurization rate of the recycled extractant is 65.8%. The experimental results show that the extractant has good recycling performance.

Example 8

Using FCC gasoline F as raw material, cut the raw material at a cutting temperature of 120°C, take light gasoline fraction, and investigate the desulfurization effect of the extractant in the process of the present invention.

The light gasoline fraction is demercaptanized by an advanced alkali washing device, and the alkali washing is conventional alkali washing (10% sodium hydroxide aqueous solution). After alkali washing, the mercaptan sulfur content in the light gasoline fraction is reduced to 20.3ug/g; The light gasoline fraction enters the extraction and desulfurization unit, the extraction agent is recovered nitrogen-formylmorpholine, the solvent-to-oil ratio is 2:1, the number of extraction stages is 4, and the extraction temperature is 30°C to obtain the alkali washing-extraction light gasoline fraction and Extraction phase: remove thiophene, mercaptan, sulfide, and disulfide-like sulfides in light distillate gasoline; alkali washing-extract light gasoline fraction into the washing device, the detergent is formamide, and remove the extractant in refined gasoline fraction , to obtain alkali washing-extraction-washing light gasoline fraction.

The sulfur content of the raw material light fraction is 244.0ug/g, and the sulfur content is reduced to 49.0ug/g after alkali washing, extraction and washing. It can be seen that the extraction desulfurization process in the process of the present invention has a higher desulfurization ability, and can make the sulfur in the light gasoline fraction The content reaches the standard of ≯50u g/g.

Claims (8)

1. reduce a method for content of sulfur in gasoline, it is characterized in that comprising the following steps:

(1). catalytically cracked gasoline raw material is cut into light gasoline fraction, heavy naphtha, and wherein the cut point of light gasoline fraction and heavy naphtha is 60 ℃-100 ℃;

(2). light gasoline fraction removes mercaptan, hydrogen sulfide and phenols acidic substance wherein through soda finishing mercaptan removal, obtains alkali cleaning light gasoline fraction;

(3). alkali cleaning light gasoline fraction removes thiophene, mercaptan, thioether, disulfides sulfide wherein through extraction, obtains alkali cleaning-extraction light gasoline fraction and extraction phase;

(4). in step (3), extraction phase enters reboiler, steams the sulfur-bearing light gasoline fraction in extraction phase, reclaims extraction agent, and regeneration temperature is 80 ℃～110 ℃; The extraction agent of regeneration recycles, the sour gasoline steaming hydrogenating desulfurization together with heavy naphtha;

(5). in step (3), alkali cleaning-extraction lighting end gasoline, through carrying out washing treatment, removes the extraction agent dissolving in oil, obtains alkali cleaning-extraction-washing light gasoline fraction;

(6). heavy naphtha contacts with Hydrobon catalyst together with hydrogen mixing with the sulfur-bearing light gasoline fraction steaming from extraction phase, carries out selective hydrodesulfurization reaction, obtains hydrogenated heavy gasoline cut;

(7). hydrogenated heavy gasoline cut and alkali cleaning-extraction-washing light gasoline fraction are mixed to get sulphur content ≯ 50ug/g gasoline products or sulphur content ≯ 10ug/g gasoline products.

2. reduce according to claim 1 the method for content of sulfur in gasoline, the flow process that it is characterized in that reducing content of sulfur in gasoline method is as follows: gasoline stocks enters separation column 2 through pipeline 1 and cuts into gently, heavy naphtha, wherein heavy naphtha is after pipeline 4 mixes with the sour distillate oil from pipeline 19, through pipeline 5, enter pump 6, heavy naphtha after boosting is after pipeline 7 mixes with from the hydrogen of pipeline 27, through pipeline 8, enter process furnace 9, material after heating enters reactor 11 through pipeline 10 and contacts with Hydrobon catalyst, hydrogenated oil enters high-pressure separator 21 through pipeline 12, from separator 21 tops hydrogen-rich gas out, through pipeline 23, enter compressor 24, hydrogen-rich gas after compression is through pipeline 25 and inlet pipe line 27 together with supplementary live gas from pipeline 26, with from the heavy distillate of pipeline 7, mix.From separator 21 bottoms hydrogenated heavy gasoline cut out, through pipeline 22, mix stabilizer tower with the alkali cleaning-extraction-washing light gasoline fraction from pipeline 29; Lighting end gasoline enters alkali cleaning treating tower 13 through pipeline 3, gasoline after caustic wash desulfuration alcohol enters extraction tower 15 through pipeline 14, from extraction tower 15 bottoms extraction phase out, through pipeline 17, enter revivifier 18, the extraction agent of separating from revivifier 18 bottoms enters extraction tower 15 tops through pipeline 20, from the sour distillate oil of revivifier 18 recovered overhead through pipeline 19 and heavy distillate mixing back end hydrogenation processing from pipeline 4; From the desulfurization benzoline out of extraction tower 15 tops, through pipeline 16, enter washing device 28, lighting end after washing through pipeline 29 with from the heavy distillate of pipeline 22, mix, mixed gasoline enters stabilizer tower 31 through pipeline 30, and separation obtains lighter hydrocarbons and gasoline products is drawn through pipeline 32,33 respectively.

3. according to the method that reduces content of sulfur in gasoline described in claim 1 and 2, it is characterized in that full catalytically cracked gasoline raw material distillation gasoline to cut into light gasoline fraction and heavy naphtha, cutting temperature is 60 ℃～100 ℃.

4. according to the method that reduces content of sulfur in gasoline described in claim 1 and 2, it is characterized in that first light gasoline fraction enters soda finishing desulfurization unit, remove mercaptan, hydrogen sulfide and phenols acidic substance in light gasoline fraction, obtain alkali cleaning light gasoline fraction.

5. according to the method that reduces content of sulfur in gasoline described in claim 1 and 2, it is characterized in that catalytically cracked gasoline raw material also can carry out alkali cleaning before gasoline cutting.

6. according to the method that reduces content of sulfur in gasoline described in claim 1 and 2, it is characterized in that alkali cleaning light gasoline fraction enters abstraction desulfurization unit, obtains alkali cleaning-extraction light gasoline fraction and extraction phase; Extraction temperature is 25 ℃～60 ℃ of normal temperature, and extraction cells mainly removes the thiophene in lighting end gasoline, removes mercaptan, thioether, disulfides sulfide simultaneously.

7. according to the method that reduces content of sulfur in gasoline described in claim 1 and 2, it is characterized in that extraction phase enters reboiler, steam the sulfur-bearing light gasoline fraction in extraction phase, the extraction agent of regeneration recycles, and regeneration temperature is 80 ℃～110 ℃.

8. according to the method that reduces content of sulfur in gasoline described in claim 1 and 2, it is characterized in that desulfurization light gasoline fraction enters washing tower washing, remove the extraction agent being dissolved in oil, obtain refining light gasoline fraction; Washing composition is by water, methyl alcohol, ethanol, ethylene glycol, glycerol, and methane amide, or its mixture, washing times comprises one or many.

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