阅读说明：本技术 一种脱硫汽油降苯增产芳烃的方法 (Method for reducing benzene and increasing aromatic hydrocarbon yield of desulfurized gasoline ) 是由 杨涛 汤玉敏 费翔 金海刚 韩雪 卜晓玲 于 2020-05-26 设计创作，主要内容包括：本发明涉及一种脱硫汽油降苯增产芳烃的方法,所述方法包括：将脱硫汽油经至少2次精馏切割得到轻馏分、中馏分及重馏分；所述轻馏分的馏程小于70℃；所述中馏分的馏程为70-155℃；所述重馏分的馏程大于155℃。本发明通过利用催化汽油中产品分布特点,通过精馏分离技术对催化汽油进行轻、中、重组分的切割,从而实现降低脱硫汽油的蒸气压及苯含量,又可部分降低汽油烯烃含量,进一步地,还可将富含C6-C8的中馏分送至重整和芳烃联合装置增产芳烃。(The invention relates to a method for reducing benzene and increasing aromatic hydrocarbon yield of desulfurized gasoline, which comprises the following steps: rectifying and cutting the desulfurized gasoline for at least 2 times to obtain light fraction, medium fraction and heavy fraction; the distillation range of the light fraction is less than 70 ℃; the distillation range of the middle distillate is 70-155 ℃; the distillation range of the heavy fraction is more than 155 ℃. The invention utilizes the product distribution characteristics in the catalytic gasoline and cuts light, medium and heavy components of the catalytic gasoline by a rectification separation technology, thereby realizing the reduction of the vapor pressure and the benzene content of the desulfurized gasoline, partially reducing the olefin content of the gasoline, and further sending the middle fraction rich in C6-C8 to a reforming and aromatic hydrocarbon combined device to increase the yield of aromatic hydrocarbon.)

1. A method for reducing benzene and increasing aromatic hydrocarbon yield of desulfurized gasoline is characterized by comprising the following steps: rectifying and cutting the desulfurized gasoline for at least 2 times to obtain light fraction, medium fraction and heavy fraction; the distillation range of the light fraction is less than 70 ℃; the distillation range of the middle distillate is 70-155 ℃; the distillation range of the heavy fraction is more than 155 ℃.

2. The method of claim 1, wherein the sources of the second rectification feed in the method comprise a first rectification column, a first rectification column bottom and a first rectification column top;

preferably, the middle distillate is used for increasing the yield of aromatic hydrocarbon;

preferably, the top pressure of the rectifying and cutting tower is 0.05-0.7 MPag.

3. The method of claim 2, wherein the second rectification feed is sourced from a first rectification column, and the method comprises cutting the desulfurized gasoline by the first rectification to obtain a light fraction at the top of the column, obtaining an intermediate product in the column, obtaining a heavy fraction at the bottom of the column, and cutting the intermediate product by the second rectification to obtain an overhead product and a bottom product;

preferably, the rectifying tower for the second rectifying and cutting comprises a stripping tower;

preferably, the overhead product is returned to the first rectification;

preferably, the bottoms product is the middle distillate;

preferably, the feed temperature of the desulfurized gasoline is 140-165 ℃;

preferably, the feed temperature of the intermediate product in the second fractional distillation cut is 100-120 ℃;

preferably, the overhead product is returned at a location 1-3 plates above the intermediate product withdrawal location.

4. The method according to claim 3, characterized in that reflux operation is arranged in the tower top extraction in the first rectification cutting;

preferably, the reflux ratio mol/mol in the reflux operation is 1.50-2.33;

preferably, reboiling operation is performed in the tower bottom extraction in the first rectification cutting;

preferably, the gasification rate in the reboiling operation is 20-30%;

preferably, the temperature of the tower top in the first rectification cutting is 60-80 ℃;

preferably, the temperature of the bottom of the first distillation cut is 200-225 ℃.

5. The method according to claim 3 or 4, characterized in that reboiling is provided in the bottom extraction in the second rectification cutting;

preferably, the gasification rate in the reboiling operation is 20-30%;

preferably, the temperature of the top of the second rectification cutting tower is 100-120 ℃;

preferably, the temperature of the bottom of the second distillation cut is 105-130 ℃.

6. The method of claim 2, wherein the second rectification material is from the bottom of the first rectification column, and the method comprises cutting the desulfurized gasoline by the first rectification to obtain a light fraction at the top of the column and an intermediate product at the bottom of the column, cutting the intermediate product by the second rectification to obtain a middle fraction at the top of the column and a heavy fraction at the bottom of the column;

preferably, the intermediate product is subjected to heat exchange with the heavy fraction before the second rectification cutting;

preferably, the feed temperature of the desulfurized gasoline is 140-165 ℃;

preferably, the feed temperature of the intermediate product in the second fractional distillation cut is 150-175 ℃.

7. The method of claim 6, wherein the first rectification cut is provided with a recovery operation in the overhead extraction;

preferably, the reflux ratio in the reflux operation is 0.5-2.0 mol/mol;

preferably, the tower bottom extraction in the first rectification cutting is provided with reboiling operation;

preferably, the gasification rate in the reboiling operation is 20-30%;

preferably, the temperature of the tower top in the first rectification cutting is 60-80 ℃;

preferably, the temperature of the bottom of the first rectification cutting is 130-150 ℃;

preferably, reboiling operation is performed in the tower bottom extraction in the second rectification cutting;

preferably, the gasification rate in the reboiling operation is 20-30%;

preferably, the temperature of the top of the second rectification cutting tower is 120-140 ℃;

preferably, the temperature of the bottom of the second rectification cut is 190-210 ℃.

8. The method of claim 2, wherein the second rectification material is obtained from the top of the first rectification tower, and the method comprises cutting the desulfurized gasoline by the first rectification to obtain an intermediate product at the top of the tower, obtaining a heavy fraction at the bottom of the tower, cutting the intermediate product by the second rectification to obtain a light fraction at the top of the tower, and obtaining a middle fraction at the bottom of the tower;

preferably, the intermediate product is subjected to heat exchange with the heavy fraction before the second rectification cutting;

preferably, the feed temperature of the desulfurized gasoline is 140-165 ℃;

preferably, the feed temperature of the intermediate product in the second fractional distillation cut is 105-125 ℃.

9. The method of claim 8, wherein the first rectification cut is provided with a recovery operation in the overhead extraction;

preferably, the reflux ratio in the reflux operation is 0.5-2.0 mol/mol;

preferably, the tower bottom extraction in the first rectification cutting is provided with reboiling operation;

preferably, the gasification rate in the reboiling operation is 20-30%;

preferably, the temperature of the top of the first rectification cutting is 100-120 ℃;

preferably, the temperature of the bottom of the first rectification cutting is 185-210 ℃;

preferably, reboiling operation is performed in the tower bottom extraction in the second rectification cutting;

preferably, the gasification rate in the reboiling operation is 20-30%;

preferably, the temperature of the tower top in the second rectification cutting is 55-80 ℃;

preferably, the temperature of the bottom of the second rectification cut is 110-135 ℃.

10. The method of any one of claims 1-9, wherein the method comprises: rectifying and cutting the desulfurized gasoline for at least 2 times to obtain light fraction, medium fraction and heavy fraction; the distillation range of the light fraction is less than 70 ℃; the distillation range of the middle distillate is 70-155 ℃; the distillation range of the heavy fraction is more than 155 ℃; the sources of the second rectification material in the method comprise the middle part of the first rectification tower, the bottom of the first rectification tower and the top of the first rectification tower; the middle distillate is used for increasing the yield of aromatic hydrocarbon; the top pressure of the rectifying and cutting middle tower is 0.05-0.7 MPag;

in the method, the second rectification material is sourced from a first rectification tower, the method comprises the steps of cutting desulfurized gasoline through first rectification to obtain light fraction at the tower top, obtaining an intermediate product in the tower, obtaining heavy fraction at the tower bottom, and obtaining a tower top product and a tower bottom product through second rectification and cutting of the intermediate product; the rectifying tower for the second rectifying and cutting comprises a stripping tower; the tower top product returns to the first rectification; the position of the top product return is 1-3 plates above the position of the intermediate product extraction; the bottom product is the middle distillate; the feeding temperature of the desulfurized gasoline is 140-165 ℃; the feeding temperature of the intermediate product in the second rectification cutting is 100-120 ℃; reflux operation is arranged in the extraction of the tower top in the first rectification cutting; the reflux ratio mol/mol in the reflux operation is 1.50-2.33; reboiling operation is arranged in the tower bottom extraction in the first rectification cutting; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the first rectification cutting is 60-80 ℃; the temperature of the bottom of the first rectification cutting is 200-225 ℃; reboiling operation is arranged in the tower bottom extraction in the second rectification cutting; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the second rectification cutting is 100-120 ℃; the temperature of the bottom of the second rectification cutting is 105-130 ℃;

in the method, the source of the second rectification material is the bottom of the first rectification tower, the method comprises the steps of cutting the desulfurized gasoline by the first rectification to obtain light fraction at the tower top and obtain an intermediate product at the tower bottom, cutting the intermediate product by the second rectification to obtain middle fraction at the tower top and obtain heavy fraction at the tower bottom; exchanging heat with the heavy fraction before the intermediate product is subjected to secondary rectification cutting; the feeding temperature of the desulfurized gasoline is 140-165 ℃; the feeding temperature of the intermediate product in the second rectification cutting is 150-175 ℃; the reflux ratio in the reflux operation is 0.5-2.0 mol/mol; the tower bottom extraction in the first rectification cutting is provided with reboiling operation; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the first rectification cutting is 60-80 ℃; the temperature of the bottom of the first rectification cutting tower is 130-150 ℃; reboiling operation is arranged in the tower bottom extraction in the second rectification cutting; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the second rectification cutting is 120-140 ℃; the temperature of the bottom of the second rectification cutting is 190-210 ℃;

in the method, the source of the second rectification material is the top of a first rectification tower, the method comprises the steps of cutting desulfurized gasoline through the first rectification to obtain an intermediate product at the top of the tower, obtaining a heavy fraction at the bottom of the tower, cutting the intermediate product through the second rectification to obtain a light fraction at the top of the tower, and obtaining a middle fraction at the bottom of the tower; exchanging heat with the heavy fraction before the intermediate product is subjected to secondary rectification cutting; the feeding temperature of the desulfurized gasoline is 140-165 ℃; the feeding temperature of the intermediate product in the second rectification cutting is 105-125 ℃; the first rectification cutting is performed by extracting the top of the tower and performing recovery operation; the reflux ratio in the reflux operation is 0.5-2.0 mol/mol; the tower bottom extraction in the first rectification cutting is provided with reboiling operation; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the first rectification cutting is 100-120 ℃; the temperature of the bottom of the first rectification cutting is 185-210 ℃; reboiling operation is arranged in the tower bottom extraction in the second rectification cutting; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the second rectification cutting is 55-80 ℃; the temperature of the bottom of the second rectification cutting is 110-135 ℃.

Technical Field

The invention relates to the field of gasoline, in particular to a method for reducing benzene and increasing aromatic hydrocarbon yield of desulfurized gasoline.

Background

At present, catalytic cracking gasoline is a main blending component of finished fuel gasoline, accounts for more than 70% of the finished gasoline in the market, the quality of the catalytic gasoline has great influence on the quality upgrading of the finished gasoline, and the standards of olefin reduction, vapor pressure reduction, benzene reduction and octane number improvement on the catalytic gasoline are constantly improved in the quality upgrading process of the gasoline, which is also a problem of the current national VI standard. The distribution characteristics of olefin, benzene and high-octane components in the distillation range of the gasoline are discovered through detailed analysis of the desulfurized and refined catalytic gasoline, and the catalytic gasoline is characterized in that 70% of the olefin in the gasoline is concentrated in light fraction; about 30-45% of the C6-C8 naphthenes and aromatics in gasoline are concentrated in the middle distillate, which is a good reforming feedstock with a high potential for middle distillate aromatics. The current situation that the gasoline capacity is excessive and the aromatic hydrocarbon raw material is in shortage in the downstream chemical basic raw material at present is combined, the catalytic gasoline is reasonably and clearly fractionated into light, medium and heavy fractions, and the indexes of the gasoline are further improved.

Through investigation, it was found that: at present, most of the catalytic gasoline quality upgrading technologies at home and abroad divide gasoline into light and heavy fractions, and then carry out subsequent treatment respectively, so that the aim of keeping olefin components with high octane number as much as possible and carrying out deep hydrodesulfurization is achieved, the loss of the octane number is finally reduced in the desulfurization process, and the middle fraction is not taken as a reforming raw material and is not subjected to benzene reduction and vapor pressure reduction.

While CN104673363A discloses a method for increasing octane number of catalytically cracked gasoline by: the catalytic cracking gasoline is divided into light, medium and heavy fractions according to the boiling range from low to high; then carrying out aromatization/hydroisomerization reaction in the presence of a catalyst, leading out a product obtained by the aromatization/hydroisomerization reaction, and mixing the product with a light fraction and a heavy fraction to obtain modified gasoline; thereby effectively improving the octane number of the catalytic cracking gasoline. CN101649221A discloses a method for producing a reformed raw material by using a gasoline light middle distillate, in particular to a method for producing a catalytic reformed raw material by using the gasoline light middle distillate as a raw material, wherein the catalytic reformed raw material is refined by selective solvent extraction and rectification under the condition of no hydrogen. Although the method realizes the improvement of partial indexes, the process is complex, and the method is not beneficial to popularization and use of the process and other problems.

Disclosure of Invention

In view of the problems in the prior art, the invention aims to provide a method for reducing benzene and increasing aromatic hydrocarbon yield of desulfurized gasoline, which can reduce the vapor pressure and benzene content of desulfurized gasoline, partially reduce the olefin content of gasoline, and further send middle distillate rich in C6-C8 to a reforming and aromatic hydrocarbon combination device to increase aromatic hydrocarbon yield.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a method for reducing benzene and increasing aromatic hydrocarbon yield of desulfurized gasoline, which comprises the following steps: rectifying and cutting the desulfurized gasoline for at least 2 times to obtain light fraction, medium fraction and heavy fraction; the distillation range of the light fraction is less than 70 ℃; the distillation range of the middle distillate is 70-155 ℃; the distillation range of the heavy fraction is more than 155 ℃.

The invention utilizes the product distribution characteristics in the catalytic gasoline and cuts light, medium and heavy components of the catalytic gasoline by a rectification separation technology, thereby realizing the reduction of the vapor pressure and the benzene content of the desulfurized gasoline, partially reducing the olefin content of the gasoline, and further sending the middle fraction rich in C6-C8 to a reforming and aromatic hydrocarbon combined device to increase the yield of aromatic hydrocarbon.

In the present invention, the distillation range of the light fraction is less than 70 ℃, and may be, for example, 70 ℃, 65 ℃, 55 ℃ or 45 ℃ or the like, but is not limited to the values listed, and other values not listed in the range are also applicable.

In the present invention, the distillation range of the middle distillate is 70 to 155 ℃ and may be, for example, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃ or 155 ℃ or the like, but is not limited to the recited values, and other values not recited in the range are also applicable.

In the present invention, the distillation range of the heavy fraction is more than 155 ℃ and may be, for example, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 175 ℃, 180 ℃, 190 ℃, 195 ℃ or 200 ℃, but the present invention is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.

As a preferable technical scheme of the invention, the sources of the second rectification material in the method comprise the first rectification tower, the first rectification tower bottom and the first rectification tower top.

Preferably, the middle distillate is used for increasing the yield of the aromatic hydrocarbon.

Preferably, the top pressure of the rectifying and cutting tower is 0.05-0.7 MPag.

As a preferable technical scheme, the second rectification material in the method is sourced from the first rectification tower, the method comprises the steps of cutting the desulfurized gasoline through the first rectification, obtaining light fraction at the top of the tower, obtaining an intermediate product in the tower, obtaining heavy fraction at the bottom of the tower, and obtaining a top product and a bottom product through the second rectification and cutting of the intermediate product.

Preferably, the rectification column used for the second rectification cut comprises a stripping column.

Preferably, the overhead product is returned to the first rectification.

Preferably, the bottoms product is the middle distillate.

Preferably, the desulfurized gasoline has a feed temperature of 140-165 deg.C, such as 140 deg.C, 145 deg.C, 150 deg.C, 155 deg.C, 160 deg.C, or 165 deg.C, but is not limited to the recited values, and other values not recited within this range are equally applicable.

Preferably, the feed temperature of the intermediate product in the second fractional distillation cut is 100 ℃ to 120 ℃, and may be, for example, 100 ℃, 104 ℃, 108 ℃, 112 ℃, 116 ℃ or 120 ℃, etc., but is not limited to the recited values, and other values not recited in the range are also applicable.

Preferably, the point at which the overhead product is returned is 1 to 3 plates above the point at which the intermediate product is withdrawn, and may be, for example, 1 plate, 2 plates, 3 plates, or the like, but is not limited to the number of plates recited, and other numbers of plates not recited in this range are equally applicable.

As a preferable technical scheme of the invention, reflux operation is arranged in the extraction of the tower top in the first rectification cutting.

Preferably, the reflux ratio mol/mol in the reflux operation is 1.50 to 2.33, and may be, for example, 1.50, 1.60, 1.70, 1.80, 1.90, 2.00, 2.10, 2.20, 2.30 or 2.33, but is not limited to the values listed, and other values not listed in this range are also applicable.

Preferably, reboiling operation is arranged in the tower bottom extraction in the first rectification cutting.

Preferably, the vaporization rate in the reboiling operation is 20 to 30%, and may be, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or the like, but is not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the temperature at the top of the first rectification cut is 60 to 80 ℃, for example, 60 ℃, 65 ℃, 70 ℃, 75 ℃ or 120 ℃, etc., but not limited to the recited values, and other values not recited in the range are also applicable.

Preferably, the temperature of the bottom of the first distillation cut is 200 ℃ to 225 ℃, such as 220 ℃, 221 ℃, 222 ℃, 223 ℃, 224 ℃ or 225 ℃, but not limited to the values listed, and other values not listed in the range are also applicable.

In a preferred embodiment of the present invention, the second rectification and cutting step is performed by reboiling during the extraction of the bottom of the column.

Preferably, the vaporization rate in the reboiling operation is 20 to 30%, and may be, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or the like, but is not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the temperature at the top of the second distillation cut is 100-120 ℃, such as 100 ℃, 104 ℃, 108 ℃, 112 ℃, 116 ℃ or 120 ℃, but not limited to the values listed, and other values not listed in the range are equally applicable.

Preferably, the temperature of the bottom of the second distillation cut is 105-130 ℃, such as 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃ or 130 ℃, but not limited to the enumerated values, and other unrecited values in the range are also applicable.

As a preferred technical scheme of the invention, the source of the second rectification material in the method is the bottom of the first rectification tower, the method comprises the steps of cutting the desulfurized gasoline by the first rectification, obtaining light fraction at the tower top, obtaining an intermediate product at the tower bottom, cutting the intermediate product by the second rectification, obtaining middle fraction at the tower top, and obtaining heavy fraction at the tower bottom.

Preferably, the intermediate product is heat exchanged with the heavy fraction before the second rectification cut.

Preferably, the desulfurized gasoline has a feed temperature of 140-165 deg.C, such as 140 deg.C, 145 deg.C, 150 deg.C, 155 deg.C, 160 deg.C, or 165 deg.C, but is not limited to the recited values, and other values not recited within this range are equally applicable.

Preferably, the feeding temperature of the intermediate product in the second fractional distillation is 150-175 ℃, such as 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃ or 175 ℃ and the like, but not limited to the recited values, and other values not recited in the range are also applicable.

As a preferable technical scheme of the invention, the first rectification cutting is provided with a recovery operation in the tower top extraction.

The reflux ratio in the reflux operation is preferably 0.5 to 2.0 mol/mol, and may be, for example, 0.5, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8 or 2.0, but is not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the tower bottom extraction in the first rectification cutting is provided with a reboiling operation.

Preferably, the vaporization rate in the reboiling operation is 20 to 30%, and may be, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or the like, but is not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the temperature at the top of the first rectification cut is 60 to 80 ℃, for example, 60 ℃, 65 ℃, 70 ℃, 75 ℃ or 120 ℃, etc., but not limited to the recited values, and other values not recited in the range are also applicable.

Preferably, the temperature of the bottom of the first distillation cut is 130-150 ℃, such as 130 ℃, 134 ℃, 138 ℃, 142 ℃, 146 ℃ or 150 ℃, but not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, reboiling operation is arranged in the tower bottom extraction in the second rectification cutting.

Preferably, the vaporization rate in the reboiling operation is 20 to 30%, and may be, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or the like, but is not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the temperature at the top of the second distillation cut is 120-140 ℃, such as 120 ℃, 125 ℃, 130 ℃, 135 ℃ or 140 ℃, but not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the temperature of the bottom of the second distillation cut is 190-210 ℃, such as 190 ℃, 195 ℃, 200 ℃, 205 ℃ or 210 ℃, but not limited to the recited values, and other values not recited in the range are also applicable.

As a preferable technical scheme of the invention, the second rectification material in the method is from the top of the first rectification tower, the method comprises the steps of cutting the desulfurized gasoline through the first rectification, obtaining an intermediate product at the top of the tower, obtaining a heavy fraction at the bottom of the tower, cutting the intermediate product through the second rectification, obtaining a light fraction at the top of the tower, and obtaining a middle fraction at the bottom of the tower.

Preferably, the intermediate product is heat exchanged with the heavy fraction before the second rectification cut.

Preferably, the desulfurized gasoline has a feed temperature of 140-165 deg.C, such as 140 deg.C, 145 deg.C, 150 deg.C, 155 deg.C, 160 deg.C, or 165 deg.C, but is not limited to the recited values, and other values not recited within this range are equally applicable.

Preferably, the feeding temperature of the intermediate product in the second fractional distillation is 105-125 ℃, for example 105 ℃, 110 ℃, 115 ℃, 120 ℃ or 125 ℃, etc., but not limited to the recited values, and other values not recited in the range are also applicable.

As a preferable technical scheme of the invention, the first rectification cutting is provided with a recovery operation in the tower top extraction.

The reflux ratio in the reflux operation is preferably 0.5 to 2.0 mol/mol, and may be, for example, 0.5, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8 or 2.0, but is not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the tower bottom extraction in the first rectification cutting is provided with a reboiling operation.

Preferably, the vaporization rate in the reboiling operation is 20 to 30%, and may be, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or the like, but is not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the temperature at the top of the first distillation cut is 100 ℃ to 120 ℃, and may be, for example, 100 ℃, 105 ℃, 110 ℃, 115 ℃ or 120 ℃, etc., but is not limited to the recited values, and other values not recited in the range are also applicable.

Preferably, the temperature of the bottom of the first distillation cut is 185-210 ℃.

Preferably, reboiling operation is arranged in the tower bottom extraction in the second rectification cutting.

Preferably, the vaporization rate in the reboiling operation is 20 to 30%, and may be, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or the like, but is not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the temperature at the top of the second rectification cut is 55 to 80 ℃, and may be, for example, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃ or 80 ℃, but is not limited to the values listed, and other values not listed in the range are also applicable.

Preferably, the temperature of the bottom of the second distillation cut is 110-135 ℃, such as 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃ or 135 ℃, but not limited to the enumerated values, and other unrecited values in the range are also applicable.

As a preferred technical solution of the present invention, the method comprises: rectifying and cutting the desulfurized gasoline for at least 2 times to obtain light fraction, medium fraction and heavy fraction; the distillation range of the light fraction is less than 70 ℃; the distillation range of the middle distillate is 70-155 ℃; the distillation range of the heavy fraction is more than 155 ℃; the sources of the second rectification material in the method comprise the middle part of the first rectification tower, the bottom of the first rectification tower and the top of the first rectification tower; the middle distillate is used for increasing the yield of aromatic hydrocarbon; the top pressure of the rectifying and cutting middle tower is 0.05-0.7 MPag;

in the method, the second rectification material is sourced from a first rectification tower, the method comprises the steps of cutting desulfurized gasoline through first rectification to obtain light fraction at the tower top, obtaining an intermediate product in the tower, obtaining heavy fraction at the tower bottom, and obtaining a tower top product and a tower bottom product through second rectification and cutting of the intermediate product; the rectifying tower for the second rectifying and cutting comprises a stripping tower; the tower top product returns to the first rectification; the position of the top product return is 1-3 plates above the position of the intermediate product extraction; the bottom product is the middle distillate; the feeding temperature of the desulfurized gasoline is 140-165 ℃; the feeding temperature of the intermediate product in the second rectification cutting is 100-120 ℃; reflux operation is arranged in the extraction of the tower top in the first rectification cutting; the reflux ratio mol/mol in the reflux operation is 1.50-2.33; reboiling operation is arranged in the tower bottom extraction in the first rectification cutting; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the first rectification cutting is 60-80 ℃; the temperature of the bottom of the first rectification cutting is 200-225 ℃; reboiling operation is arranged in the tower bottom extraction in the second rectification cutting; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the second rectification cutting is 100-120 ℃; the temperature of the bottom of the second rectification cutting is 105-130 ℃;

in the method, the source of the second rectification material is the bottom of the first rectification tower, the method comprises the steps of cutting the desulfurized gasoline by the first rectification to obtain light fraction at the tower top and obtain an intermediate product at the tower bottom, cutting the intermediate product by the second rectification to obtain middle fraction at the tower top and obtain heavy fraction at the tower bottom; exchanging heat with the heavy fraction before the intermediate product is subjected to secondary rectification cutting; the feeding temperature of the desulfurized gasoline is 140-165 ℃; the feeding temperature of the intermediate product in the second rectification cutting is 150-175 ℃; the reflux ratio in the reflux operation is 0.5-2.0 mol/mol; the tower bottom extraction in the first rectification cutting is provided with reboiling operation; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the first rectification cutting is 60-80 ℃; the temperature of the bottom of the first rectification cutting tower is 130-150 ℃; reboiling operation is arranged in the tower bottom extraction in the second rectification cutting; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the second rectification cutting is 120-140 ℃; the temperature of the bottom of the second rectification cutting is 190-210 ℃;

in the method, the source of the second rectification material is the top of a first rectification tower, the method comprises the steps of cutting desulfurized gasoline through the first rectification to obtain an intermediate product at the top of the tower, obtaining a heavy fraction at the bottom of the tower, cutting the intermediate product through the second rectification to obtain a light fraction at the top of the tower, and obtaining a middle fraction at the bottom of the tower; exchanging heat with the heavy fraction before the intermediate product is subjected to secondary rectification cutting; the feeding temperature of the desulfurized gasoline is 140-165 ℃; the feeding temperature of the intermediate product in the second rectification cutting is 105-125 ℃; the first rectification cutting is performed by extracting the top of the tower and performing recovery operation; the reflux ratio in the reflux operation is 0.5-2.0 mol/mol; the tower bottom extraction in the first rectification cutting is provided with reboiling operation; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the first rectification cutting is 100-120 ℃; the temperature of the bottom of the first rectification cutting is 185-210 ℃; reboiling operation is arranged in the tower bottom extraction in the second rectification cutting; the gasification rate in the reboiling operation is 20-30%; the temperature of the tower top in the second rectification cutting is 55-80 ℃; the temperature of the bottom of the second rectification cutting is 110-135 ℃.

Compared with the prior art, the invention has the following beneficial effects:

(1) the method provided by the invention can reduce the vapor pressure of the desulfurized gasoline to 58KPa, and further can partially reduce the olefin content of the gasoline.

(2) The method provided by the invention reduces the benzene content in the desulfurized gasoline to 0.78%, and simultaneously, the intermediate component rich in C6-C8 can be sent to a reforming and aromatic hydrocarbon combined device to increase the aromatic hydrocarbon yield and obviously reduce the energy consumption in cutting.

Drawings

FIG. 1 is a flow chart of a specific embodiment of example 1 of the present invention;

FIG. 2 is a flow chart of a specific process for carrying out example 2 of the present invention;

FIG. 3 is a flow chart of a specific embodiment of example 3 of the present invention.

The present invention is described in further detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.

Detailed Description

To better illustrate the invention and to facilitate the understanding of the technical solutions thereof, typical but non-limiting examples of the invention are as follows: