JP2011208071A - Method for producing aromatic compound and olefins - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for simultaneously producing an aromatic compound and olefins.SOLUTION: The method for producing the aromatic compound and the olefins has a process wherein a gasoline fraction having an initial boiling point and an ending point, both being in a range of 17-220°C, is thermally treated together with steam.

Description

  The present invention relates to a method for producing aromatic compounds and olefins.

  Conventionally, petrochemical plants produce olefins such as ethylene and propylene by pyrolysis in the presence of steam using naphtha fractions obtained by atmospheric distillation of crude oil as raw materials, and these olefins as raw materials. In addition, many types of petrochemical derivatives such as polyethylene and polypropylene are manufactured.

  However, in recent years, many petrochemical factories have been operating in China and Southeast Asia, increasing the demand for naphtha in the Asian region, making it difficult to obtain naphtha and increasing the price of naphtha. A method for producing the same has been studied. For example, Patent Document 1 describes a method of thermally cracking hydrocracking cycle oil or wax obtained from crude oil to obtain olefins.

JP 2005-325263 A

  By the way, as a basic raw material of a petrochemical derivative, there are aromatic compounds such as benzene, toluene and xylene in addition to olefins. However, Patent Document 1 discloses a method for obtaining an aromatic compound from an alternative raw material of naphtha. Not.

  An object of this invention is to provide the manufacturing method of an aromatic compound and olefins which can manufacture an aromatic compound and olefins simultaneously.

  That is, the present invention includes the step of heat-treating a gasoline fraction having both an initial boiling point and an end point within a range of 17 to 220 ° C. together with steam to obtain an aromatic compound and an olefin, and producing an aromatic compound and an olefin. Provide a method.

  According to the present invention, an aromatic compound and an olefin can be produced at the same time by using, as a raw material, a gasoline fraction having both an initial boiling point and an end point within the above range.

  In the production method according to the present invention, the gasoline fraction preferably contains 5-45% by mass of olefin and 0-40% by mass of aromatics based on the total mass of the gasoline fraction. .

  If the olefin content in the gasoline fraction is large, the aromatic compound can be obtained in high yield. On the other hand, the olefin content and the aromatic content are likely to generate high molecular weight compounds called coke and tar due to the polycondensation reaction in the heat treatment, and the generated high molecular weight compounds are placed in a cracking furnace or a quenching heat exchanger that performs heat treatment. Adhere to. If the amount of the high molecular weight compound produced is large, the heat treatment may be interrupted to increase the frequency of removing the high molecular weight compound adhering to the inside of the decomposition furnace or the quenching heat exchanger, which may reduce the working efficiency. In the production method according to the present embodiment, the production of high molecular weight compounds during heat treatment can be suppressed by setting the olefin content and aromatic content in the gasoline fraction to the upper limit values or less. That is, by making the olefin content and aromatic content in the gasoline fraction within the above ranges, the production efficiency of the high molecular weight compound is suppressed and the working efficiency is improved, and the aromatic compound is obtained in a high yield. Obtainable.

  In the production method according to the present invention, the steps include a convection part that mixes the gasoline fraction and steam, a radiant pipe through which the mixture of the gasoline fraction and steam that has passed through the convection part flows, and the inside of the radiant pipe. It is carried out in a manufacturing system having a heating means for heating the mixture that is circulated, and comprising a radiation part that heat-treats the gasoline fraction and a cooling part that cools the heat-treated product of the gasoline fraction that has passed through the radiation part. The mixing amount of steam in the convection part is 30 to 60 parts by mass with respect to 100 parts by mass of the gasoline fraction, the reaction pressure in the radiant tube is 0.45 MPa or less, and the reaction time is 0.1 to 0.7. Second, and the temperature of the heat-treated product that has passed through the radiant part is preferably 790 to 850 ° C. By performing the above step under such conditions, the aromatic compound can be obtained in a higher yield while suppressing the production of high molecular weight compounds such as coke and tar.

  In the step, it is preferable to heat-treat 40 parts by mass or more of naphtha together with the gasoline fraction and the steam with respect to 100 parts by mass of the gasoline fraction. According to such a process, an aromatic compound can be obtained at a higher yield while further suppressing the production of high molecular weight compounds such as coke and tar. Moreover, the amount of steam used can be reduced, and aromatic compounds and olefins can be obtained with high energy efficiency.

  According to the present invention, aromatic compounds and olefins can be produced simultaneously.

It is the schematic which illustrates the manufacturing process for manufacturing a gasoline fraction. It is a figure showing an outline of a manufacturing system concerning an embodiment.

  Preferred embodiments of the method for producing aromatic compounds and olefins of the present invention will be described below.

  In the production method according to the present embodiment, a gasoline fraction having both an initial boiling point and an end point within a range of 17 to 220 ° C. is heat-treated with steam to obtain an aromatic compound and olefins (hereinafter referred to as “heat treatment in some cases”). Process).). In the production method according to the present embodiment, an aromatic compound and an olefin can be produced at the same time by using, as a raw material, a gasoline fraction whose initial boiling point and end point are both within the above range.

  Here, “both the initial boiling point and end point are within the range of 17 to 220 ° C.” means that the initial boiling point and end point measured by JIS K2254 “Petroleum products—Distillation test method—Atmospheric pressure distillation test method” , All indicate that it is within the range of 17 to 220 ° C.

  The initial boiling point and end point of the gasoline fraction are preferably in the range of 17 to 220 ° C, and more preferably in the range of 25 to 200 ° C.

  Examples of the aromatic compound obtained by the production method according to this embodiment include benzene, toluene, and xylene. Examples of olefins include ethylene, propylene, and butylene.

  FIG. 1 is a schematic view illustrating a production process for producing a gasoline fraction. For example, the gasoline fraction may be produced through any of the production processes shown in FIG. 1 or may be a mixture of gasoline fractions produced through a plurality of production processes. Moreover, as a gasoline fraction, the gasoline fraction manufactured through manufacturing processes other than the manufacturing process shown in FIG. 1 can also be used.

  An example of a method for producing a gasoline fraction is a catalytic cracking method. The catalytic cracking method is a method for producing a high-octane gasoline fraction by cracking with a solid acid catalyst using a high-boiling fraction higher than kerosene as a raw material.

  In the catalytic cracking method, since coke adheres on the catalyst as a side reaction of the cracking reaction, the catalytic activity decreases. Therefore, it is necessary to regenerate the catalyst by burning off coke adhering to the catalyst. Examples of the catalyst include a silica alumina catalyst or a zeolite catalyst, and a zeolite catalyst is preferable from the viewpoint of versatility.

  Petroleum fractions ranging from kerosene / light diesel oil to atmospheric residual oil can be used as raw materials in the catalytic cracking process, but in general, heavy diesel oil, vacuum diesel oil or desulfurized heavy oil obtained by hydrodesulfurizing them is often used. The Further, desulfurized heavy oil obtained by hydrodesulfurizing normal pressure residue or reduced pressure residue can be used as a raw material.

  The catalytic cracking method is classified into the fixed bed type, moving bed type, and fluidized bed type depending on the catalyst regeneration method and the flow state of the catalyst used. The fluidized bed type is the most widely used method. Is generally referred to as fluid catalytic cracking.

  In the fluid catalytic cracking method, the feed oil is mixed with a catalyst in a pipe line called a riser, and a cracking reaction is performed. The cracked product and the catalyst are separated in the reaction tower, and the cracked product is further sent to the rectifying tower to be converted into products such as gasoline fraction, C4 (BB ') fraction, gas below C3, cracked light oil, etc. Divided. Waste catalyst from the reaction tower is stripped of oil by steam and then transferred to the regeneration tower. The catalyst regenerated by burning the coke deposited in the regeneration tower is sent again to the riser and used for the decomposition reaction.

  The gasoline fraction usually contains a saturated component which is a chain and cyclic saturated hydrocarbon, an aromatic component which is a hydrocarbon having an aromatic ring, and an olefin component which is a chain unsaturated hydrocarbon.

  The gasoline fraction preferably contains 5% by mass or more of olefin content, more preferably 15% by mass or more, based on the total mass of the gasoline fraction. By setting the olefin content in the gasoline fraction as described above, the aromatic compound can be obtained in a higher yield.

  The liquefied petroleum gases such as naphtha, kerosene, light oil, hydrocracking cycle oil, wax, propane and butane, which have been used as raw materials for steam pyrolysis, are mainly composed of saturated components. It was difficult to produce an aromatic compound in high yield from the raw material. On the other hand, the production method according to this embodiment can obtain an aromatic compound in a high yield by using a gasoline fraction having a high olefin content as a raw material.

  In addition, with conventional steam pyrolysis, it is difficult to selectively produce only specific compounds even if olefins and aromatic compounds as raw materials for various petrochemical derivatives can be produced simultaneously. it is conceivable that. However, the demand for individual petrochemical derivatives is not constant, and varies depending on the demand for the final product produced from the derivative and the operation of the factory. Therefore, it is desired to adjust the yield of olefins and aromatic compounds in accordance with the production of petrochemical derivatives.

  In the production method according to the present embodiment, it is considered that olefins are mainly produced from the saturated content in the gasoline fraction by the heat treatment in the presence of steam, and the aromatic compound is produced from the olefin content in the gasoline fraction. It is done. Therefore, according to the production method according to the present embodiment, the production amount of the aromatic compound and the production amount of the olefins are appropriately adjusted by appropriately adjusting the saturated content and the olefin content in the gasoline fraction. Can be changed.

  Moreover, it is preferable that a gasoline fraction contains 5-45 mass% of olefin components on the basis of the total mass of a gasoline fraction, and it is more preferable that it contains 15-40 mass%. Moreover, it is preferable to contain 0-40 mass% of aromatic components, and it is more preferable to contain 0-30 mass%.

  When the olefin content in the gasoline fraction is large, the aromatic compound can be obtained in a high yield as described above. On the other hand, the olefin content and the aromatic content are likely to generate high molecular weight compounds called coke and tar due to the polycondensation reaction in the heat treatment, and the generated high molecular weight compounds are placed in a cracking furnace or a quenching heat exchanger that performs heat treatment. Adhere to. If the amount of the high molecular weight compound produced is large, the heat treatment may be interrupted to increase the frequency of removing the high molecular weight compound adhering to the inside of the decomposition furnace or the quenching heat exchanger, which may reduce the working efficiency. In the production method according to the present embodiment, the production of high molecular weight compounds during heat treatment can be suppressed by setting the olefin content and aromatic content in the gasoline fraction to the upper limit values or less. That is, by making the olefin content and aromatic content in the gasoline fraction within the above ranges, the production efficiency of the high molecular weight compound is suppressed and the working efficiency is improved, and the aromatic compound is obtained in a high yield. Obtainable.

  A heat treatment process can be performed in a manufacturing system provided with a cracking furnace and a quenching heat exchanger, for example. FIG. 2 is a diagram showing an outline of the manufacturing system according to the present embodiment. Hereinafter, an embodiment of the heat treatment step will be described.

  The cracking furnace 1 circulates in the convection section 2 for mixing the gasoline fraction A1 and the steam B1, the radiation pipe 31 through which the mixture of the gasoline fraction and steam supplied from the convection section 2 circulates, and the radiation pipe 31. A heating means (not shown) for heating the mixture to be heated may be provided, and the radiation unit 3 for heat-treating the gasoline fraction may be provided. The quenching heat exchanger 4 includes a cooling unit that cools the heat-treated product of the gasoline fraction supplied from the radiation unit 3.

  In the convection section 2, the gasoline fraction A1 is supplied to the first convection section 21 and preheated. Next, the gasoline fraction preheated in the first convection section 21 is supplied to the second convection section 22. At this time, steam B1 preheated in the fourth convection section 24 is also supplied and supplied to the second convection section 22 together with the gasoline fraction. In the second convection section 22, the gasoline fraction and steam are mixed and preheated. Further, the mixture of the gasoline fraction and steam is supplied to the third convection section 23 and further preheated. In the convection section 2, for example, the preliminary heating can be performed using the heat of the combustion exhaust gas D <b> 1 provided from the radiation section.

  The mixture of the gasoline fraction and steam preheated in the third convection section 23 is supplied to the radiation section 3 by being equally distributed to the plurality of radiation pipes 31 via the venturi pipe 5. And in the radiation part 3, the mixture which distribute | circulates the inside of the radiation tube 31 is heat-processed by the heating means which is not shown in figure.

  The heat-treated product heat-treated in the radiation unit 3 is supplied to the quenching heat exchanger 4 and cooled. The heat-treated product C1 obtained through the quenching heat exchanger 4 contains an aromatic compound and an olefin. For example, the aromatic compound and the olefin can be taken out from the heat-treated product C1 by a distillation operation.

  Although the convection part 2 is described as having the first to fourth convection parts in FIG. 2, the convection part 2 may have one or more convection parts. Further, when steam is generated in the quenching heat exchanger 4, the steam may be heated in the convection section.

  The amount of steam mixed in the convection section 2 is preferably 30 to 60 parts by mass and more preferably 38 to 50 parts by mass with respect to 100 parts by mass of the gasoline fraction.

  By mixing steam in the convection section 2, the partial pressure is lowered and vaporization of the gasoline fraction as a raw material is promoted. In addition, the mixing of steam promotes the reaction caused by the heat treatment and improves the yield of aromatic compounds and olefins. Furthermore, the production of coke and tar is suppressed by lowering the partial pressure of the high boiling point compound that can be a precursor for coke and tar production.

  If the mixing amount of steam having such an effect is less than the above range, the yield of aromatic compounds and olefins may be lowered. In addition, the production of coke and tar is promoted, and the heat transfer performance decreases and the flow path closes rapidly. In some cases, it is necessary to remove the coke and tar by interrupting the introduction of the raw material to the cracking furnace. , Work efficiency decreases. On the other hand, if the mixing amount of steam is larger than the above range, the flow rate of steam increases and the pressure loss of the pipeline rises, so the amount of gasoline fraction used as a raw material is limited, and aromatic compounds and olefins are produced. Efficiency may be reduced. In addition, since the amount of steam used increases and energy consumption required for steam generation increases, energy efficiency decreases. Therefore, by setting the mixing amount of steam within the above range, aromatic compounds and olefins can be obtained in high yield while maintaining good working efficiency and production efficiency.

  The reaction pressure in the radiation tube 31 is preferably 0.45 MPa or less, and more preferably 0.35 MPa or less.

  In the heat treatment in the radiating section 3, the presence of steam lowers the partial pressure of the gasoline fraction and the heat treated product, thereby promoting the reaction. If the reaction pressure in the radiant tube 31 is too high, the partial pressure increases, the reaction due to heat treatment is suppressed, and the yield of aromatic compounds and olefins may decrease. In addition, the partial pressure of the high-boiling compound serving as a precursor for coke and tar generation increases, and coke and tar generation, which is a polycondensation reaction, may be promoted. Therefore, by setting the reaction pressure in the radiant tube 31 as described above, it is possible to produce aromatic compounds and olefins with high yield while maintaining good working efficiency.

  The reaction time in the radiation tube 31 is preferably 0.1 to 0.7 seconds, and more preferably 0.2 to 0.5 seconds. Here, the “reaction time” indicates the time from when the mixture of the gasoline fraction supplied from the convection section 2 and steam is supplied to the radiation section 3 until reaching the quenching heat exchanger 4.

  When reaction time is shorter than the said range, the reaction by heat processing does not fully advance and the yield of an aromatic compound and olefins falls. On the other hand, when reaction time is longer than the said range, reaction by heat processing will advance too much and the produced | generated olefins may be thermally decomposed. Therefore, by setting the reaction time within the above range, aromatic compounds and olefins can be obtained with good yield.

  The heat-treated product supplied from the radiation unit 3 preferably has a temperature of 790 to 850 ° C, and more preferably 800 to 845 ° C. Here, the temperature is a temperature obtained by measuring the outlet temperature of the radiation tube 31 (that is, the temperature at the outlet of the radiation unit 3), and is also referred to as a decomposition temperature.

  When the decomposition temperature is lower than the above range, the reaction by heat treatment does not proceed sufficiently, and the yield of aromatic compounds and olefins may be reduced. On the other hand, when the decomposition temperature is higher than the above range, a lot of coke and tar are generated, and the working efficiency may be lowered. Therefore, by setting the decomposition temperature within the above range, it is possible to obtain aromatic compounds and olefins with high yield while suppressing the production of coke and tar and preventing the work efficiency from decreasing.

  In the heat treatment step, 40 parts by mass or more of naphtha can be heat-treated together with the gasoline fraction and steam with respect to 100 parts by mass of the gasoline fraction. By heat-treating with naphtha, the amount of coke and tar produced from the gasoline fraction can be reduced. For example, by heat treatment with naphtha, the production of coke and tar is sufficiently suppressed even when the decomposition temperature is set to 800 to 845 ° C. Therefore, reducing the mixing amount of steam to improve energy efficiency, increasing the olefin content in the gasoline fraction to improve the yield of aromatic compounds, or increasing the decomposition temperature to increase aromaticity Even if the yields of compounds and olefins are improved, the working efficiency is less likely to decrease due to the production of coke and tar.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to an Example.

Example 1
The gasoline fraction (1) produced by the catalytic cracking apparatus using heavy oil / heavy light oil as a raw material was subjected to a heat treatment together with steam by applying it to a production system as shown in FIG. The properties of the gasoline fraction (1) as the raw material were as shown in Table 1. Table 2 shows the conditions for the heat treatment and the compounds obtained by the heat treatment. In the table below, “yield” indicates the content ratio of each compound when the total mass of the heat-treated product obtained after the heat treatment is 100 mass%. In Table 1, IBP represents the initial boiling point. In Table 1, the composition was measured according to JIS K2536-2 “Petroleum products-component test method Part 2: Determination of all components by gas chromatograph”. In Table 2, “others” include C5 or higher olefins, C9 or higher aromatic compounds, and the like.

(Example 2)
Heat treatment was performed in the same manner as in Example 1 except that the gasoline fraction (2) produced by a catalytic cracking apparatus using heavy oil and heavy light oil as a raw material was used instead of the gasoline fraction (1). The properties of the gasoline fraction (2) as the raw material were as shown in Table 1. Table 2 shows the conditions for the heat treatment and the compounds obtained by the heat treatment.

(Example 3)
Heat treatment was carried out in the same manner as in Example 1 except that the gasoline fraction (3) produced by a catalytic cracking apparatus using heavy oil / heavy light oil as a raw material was used instead of the gasoline fraction (1). The properties of the gasoline fraction (3) as the raw material were as shown in Table 1. Table 2 shows the conditions for the heat treatment and the compounds obtained by the heat treatment.

(Comparative Example 1)
Heat treatment was performed in the same manner as in Example 1 except that light naphtha having the properties shown in Table 1 was used instead of the gasoline fraction (1). Table 2 shows the conditions for the heat treatment and the compounds obtained by the heat treatment.

Example 4
The gasoline fraction (1) in Table 1 and light naphtha were mixed at the raw material ratio shown in Table 3, and subjected to a production system as shown in FIG. Table 3 shows the conditions for the heat treatment and the compounds obtained by the heat treatment.

(Example 5)
The gasoline fraction (2) in Table 1 and light naphtha were mixed at the raw material ratio shown in Table 4 and subjected to a heat treatment with steam by using a production system as shown in FIG. Table 4 shows the conditions for the heat treatment and the compounds obtained by the heat treatment.

(Example 6)
The gasoline fraction (3) in Table 1 and light naphtha were mixed at the raw material ratio shown in Table 5 and subjected to a production system as shown in FIG. Table 5 shows the conditions for the heat treatment and the compounds obtained by the heat treatment.

  INDUSTRIAL APPLICATION This invention can manufacture an aromatic compound and olefins simultaneously, and is industrially useful as a supply method of the basic raw material of a petrochemical derivative.

  DESCRIPTION OF SYMBOLS 1 ... Cracking furnace, 2 ... Convection part, 3 ... Radiation part, 4 ... Quenching heat exchanger, 5 ... Venturi tube, 21 ... 1st convection part, 22 ... 2nd convection part, 23 ... 3rd convection part, 24 ... Fourth convection section, 31 ... radiant tube, A1 ... gasoline fraction, B1 ... steam, C1 ... heat-treated product, D1 ... combustion exhaust gas.

Claims (4)

  A process for producing aromatic compounds and olefins, comprising a step of heat-treating a gasoline fraction having an initial boiling point and an end point within a range of 17 to 220 ° C together with steam to obtain aromatic compounds and olefins.   The said gasoline fraction contains 5-45 mass% of olefin content and 0-40 mass% of aromatic content based on the total mass of the said gasoline fraction. A process for producing aromatic compounds and olefins. The process includes
A convection section for mixing the gasoline fraction and steam;
A radiant pipe through which the mixture of the gasoline fraction and steam having passed through the convection section circulates and a heating means for heating the mixture that circulates in the radiant pipe, and a radiant section that heat-treats the gasoline fraction;
A cooling unit that cools the heat-treated product of the gasoline fraction that has passed through the radiation unit;
In a manufacturing system comprising
The mixing amount of steam in the convection part is 30 to 60 parts by mass with respect to 100 parts by mass of the gasoline fraction,
The reaction pressure in the radiation tube is 0.45 MPa or less, the reaction time is 0.1 to 0.7 seconds,
The method for producing an aromatic compound and olefins according to claim 1 or 2, wherein the temperature of the heat-treated product that has passed through the radiation part is 790 to 850 ° C.   The said process WHEREIN: 40 mass parts or more of naphtha is heat-processed with the said gasoline fraction and the said steam with respect to 100 mass parts of said gasoline fractions, The Claim 1 characterized by the above-mentioned. The manufacturing method of the aromatic compound and olefin of description.

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