Light hydrocarbon isomerization raw material treatment system and method

Abstract

The invention relates to the field of petroleum hydrocarbon products, in particular to a light hydrocarbon isomerization raw material treatment system and method. The treatment system comprises: a divided-wall tower, the middle of which is provided with a middle partition plate so as to divide the divided-wall tower into a common rectifying section, a pre-fractionation section, a middle component product extraction section and a common stripping section from top to bottom; the divided-wall tower is provided with a raw material feeding hole, a first extraction hole, a second extraction hole and a third extraction hole; the raw material feeding hole is formed in the middle of the pre-fractionation section; the first extraction opening is formed in the middle of the middle component product extraction section; the second extraction opening is formed in the top of the divided-wall tower, and the third extraction opening is formed in the bottom of the divided-wall tower; the condensation reflux unit is arranged between the second extraction opening and the divided-wall tower and is communicated with the second extraction opening; the reboiler is arranged between the divided-wall tower and the third extraction opening and is communicated with the third extraction opening; according to the treatment system, an isomerization raw material product with relatively high purity can be obtained on the basis of lowest energy consumption, and the energy medium consumption of isomerization raw material treatment is reduced.

Description

Technical Field

[0001] The present application relates to the field of petroleum hydrocarbon products, and in particular to a light hydrocarbon isomerization raw material processing system and method. Background Art

[0002] As environmental protection requirements become increasingly stringent, the National VI gasoline standard has stricter requirements on the mass fraction of olefins, aromatics, benzene, and polycyclic aromatic hydrocarbons. At present, the gasoline pool is mainly composed of catalytic gasoline and reforming gasoline. Since the mass fractions of aromatics and olefins in these two blending components are high, while the mass fractions of other components are low, adding clean gasoline blending components with high octane number, low sulfur, nitrogen, less aromatics and olefins to the gasoline pool has become a problem that major refineries must solve under the new normal of environmental protection.

[0003] The light alkane isomerization product has the characteristics of cleanliness, low aromatics, no olefins, and high octane number. Among them, the octane number of dimethylbutane research method is higher than 94, which can improve the octane number of the front end of the gasoline pool and make the octane number distribution of the gasoline fraction reasonable. It is an ideal clean gasoline blending component. The main raw material of the light hydrocarbon isomerization product is light naphtha, and the components are generally C4-C7 normal isoalkanes, cycloalkanes and a small amount of aromatics. Isomerization mainly converts low-octane normal C5 and C6 into high-octane isopentane and isohexane. Since the isomerization reaction is a balanced reaction, the less the amount of isoalkanes in the feed, the more conducive to isomerization conversion. In addition, the presence of aromatics will be hydrogenated to cycloalkanes, generating a lot of heat. At the same time, the presence of cycloalkanes also inhibits the isomerization reaction. Therefore, it is necessary to treat the isomerization raw materials to remove the C4 component and high-octane isopentane, control the benzene content to no more than 2%wt, and remove the heavier C7+ components.

[0004] At present, the treatment methods for isomerization feedstocks are usually: (1) Setting up a light-heavy tower to remove isopentane and C4 components from the top of the light-heavy tower, and removing benzene and C7+ components from the bottom of the heavy-heavy tower. (2) Using a side-line tower to remove isopentane and C4 components from the top, remove benzene and C7+ components from the bottom, and extract isomerization feed from the side line. However, the above two treatment methods consume a large amount of energy media and the energy consumption of the equipment is high, which is not conducive to the current carbon peak and carbon neutrality governance goals. Therefore, how to provide a light hydrocarbon isomerization feedstock processing system to reduce the energy medium consumption of isomerization feedstock processing is a technical problem that urgently needs to be solved. Summary of the invention

[0005] The present application provides a light hydrocarbon isomerization raw material processing system and method to solve the technical problem of excessive energy medium consumption in the processing method of isomerization raw materials in the prior art.

[0006] In a first aspect, the present application provides a processing system for light hydrocarbon isomerization feedstock, the processing system comprising:

[0007] A dividing wall tower, wherein a middle partition is provided in the middle of the dividing wall tower to divide the dividing wall tower from top to bottom into a common rectification section, a pre-fractionation section, an intermediate component product extraction section and a common stripping section, wherein the pre-fractionation section and the intermediate component product extraction section are separated by the middle partition, the common rectification section is arranged in the upper space of the middle partition, and the common stripping section is arranged in the lower space of the middle partition;

[0008] The dividing wall tower is provided with a raw material feed port, a first extraction port, a second extraction port and a third extraction port. The raw material feed port is provided in the middle of the pre-fractionation section to divide the pre-fractionation section into a pre-rectification section and a pre-stripping section; the first extraction port is provided in the middle of the intermediate component product extraction section to divide the intermediate component product extraction section into a product rectification section and a product stripping section; the second extraction port is provided at the top of the dividing wall tower, and the third extraction port is provided at the bottom of the dividing wall tower;

[0009] A condensation reflux unit, the condensation reflux unit is arranged between the second production outlet and the dividing wall tower, the condensation reflux unit is connected to the second production outlet, the feed inlet of the condensation reflux unit is connected to the top of the common distillation section, and the discharge port of the condensation reflux unit is connected to one side of the common distillation section;

[0010] A reboiler, wherein the reboiler is arranged between the dividing wall tower and the third production outlet, the reboiler unit is connected to the third production outlet, the feed port of the reboiler is connected to one side of the common distillation section, and the discharge port of the reboiler is connected to the bottom of the common distillation section.

[0011] Optionally, the condensation reflux unit also includes a top reflux tank, a condenser and a reflux pump, the feed port of the condenser is connected to the top of the common distillation section, the discharge port of the condenser is connected to the top reflux tank, the discharge port of the top reflux tank is connected to the reflux pump, the discharge port of the reflux pump is connected to one side of the common distillation section, and the discharge port of the reflux pump is also connected to the second production port.

[0012] Optionally, the common distillation section is further provided with a partition plate to distinguish the feed inlet and the discharge outlet of the condensation reflux unit.

[0013] Optionally, the processing system further includes:

[0014] A distribution control unit, the distribution control unit includes a first pipeline, a second pipeline and a third pipeline, one end of the first pipeline is connected to one side of the common distillation section, and the other end of the first pipeline is connected to one side of the second pipeline; the feed port of the second pipeline is connected to one side of the common distillation section, and the discharge port of the second pipeline is connected to the feed port of the pre-fractionation section; one end of the third pipeline is connected to one side of the common distillation section, and the other end of the third pipeline is connected to the intermediate component product extraction section.

[0015] Optionally, the distribution control unit further includes a fourth pipeline, one end of which is connected to the intermediate component product extraction section, and the other end of which is connected to one side of the common distillation section.

[0016] Optionally, the processing system further comprises a feed heat exchanger, wherein the feed heat exchanger is connected to the raw material feed port, one end of the feed heat exchanger is connected to the pre-fractionation section, one end of the feed heat exchanger is connected to the common stripping section, and the feed heat exchanger is provided with a product discharge port.

[0017] Optionally, the number of tower plates of the bulkhead tower is 80 to 130.

[0018] Optionally, the number of plates in the common distillation section is 20 to 40; and / or,

[0019] The number of the plates in the pre-fractionation section is 20 to 30; and / or,

[0020] The number of trays in the intermediate component product extraction section is 40 to 55; and / or,

[0021] The number of plates in the common stripping section is 20 to 50; and / or,

[0022] The number of the intermediate partition plates is 20 to 25.

[0023] Optionally, the operating pressure of the dividing wall tower is 0.2 MPa to 0.5 MPa.

[0024] In a second aspect, the present application provides a method for processing a light hydrocarbon isomerization feedstock, the processing method being adapted to the processing system described in the first aspect, and the processing method comprising:

[0025] Heat exchange is performed on the light naphtha raw material, followed by pre-fractionation and intermediate component product extraction to obtain a first component and a second component respectively;

[0026] The second component is subjected to common distillation, followed by condensation and reflux to obtain C4 and isopentane component products;

[0027] Reboiling and stripping the first component to obtain benzene and C7+ heavy component materials and isomerization raw materials respectively;

[0028] The isomerization feedstock is heat exchanged to utilize the heat exchange amount of the light naphtha feedstock to perform an isomerization reaction to obtain an isomerization feedstock product.

[0029] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0030] The processing system of a light hydrocarbon isomerization feedstock provided in the embodiment of the present application introduces a bulkhead tower in the processing process of the light hydrocarbon isomerization feedstock. Since the bulkhead tower is an ideal system structure in thermodynamics, the formation of entropy mixing caused by the difference in component composition between the feed and the feed tray is avoided, and the back-mixing effect of the intermediate components is also avoided. The system has a high separation efficiency, and the gas phase flow rate in the tower is smaller than the total gas phase flow rate of the conventional two-tower process. For a given material, to complete the same separation task, the bulkhead tower requires less reboil heat and cooling than the conventional two-tower process or the side-line extraction process. The condensation amount is reduced, and the middle partition is used to separate the raw material feed port and the production port to prevent the remixing of the separated components. The condensation amount and reheating amount required to reduce the reflux amount of the components are reduced in conjunction with the condensation reflux unit and the reboiler, so that a large amount of isomerized raw material products can be accumulated in the intermediate component product production section. Since isomerization is a concentration equilibrium reaction, the higher the content of normal alkane components in the isomerization raw material, the more conducive it is to the conversion of alkane isomerization. Therefore, a higher purity isomerized raw material product can be obtained on the basis of the lowest energy consumption, reducing the energy medium consumption of isomerization raw material processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0033] Figure 1 A schematic diagram of the structure of the processing system provided in the embodiment of the present application;

[0034] Figure 2 A schematic diagram of a process flow of a processing method provided in an embodiment of the present application;

[0035] Figure 3 A schematic diagram of the side distillation tower structure provided in the embodiment of the present application;

[0036] Figure 4 A schematic diagram of the structure of two towers for removing light and heavy particles provided in an embodiment of the present application;

[0037] Among them, 101-common distillation section, 102-pre-fractionation section, 103-intermediate component product extraction section, 104-common stripping section, 1-feed heat exchanger, 2-dividing wall tower, 3-condenser, 4-tower top reflux tank, 5-reflux pump, 6-reboiler, 7-dividing tower plate, 8-middle partition, 9-raw material feed port, 10-second extraction port, 11-third extraction port, 12-first extraction port, 13-distribution control unit Element, 131-first pipeline, 132-second pipeline, 133-third pipeline, 134-fourth pipeline, 14-tower reflux material, 15-lightness removal tower, 16-lightness removal tower top condenser, 17-lightness removal tower reflux tank, 18-lightness removal tower reflux pump, 19-lightness removal tower reboiler, 20-heavy removal tower, 21-heavy removal tower top condenser, 22-heavy removal tower reflux tank, 23-heavy removal tower reflux pump, 24-heavy removal tower reboiler. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0039] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0040] like Figure 1 As shown, the embodiment of the present application provides a processing system for light hydrocarbon isomerization raw materials, and the processing system includes:

[0041] A dividing wall tower 2, wherein a middle partition 8 is provided in the middle of the dividing wall tower 2 to divide the dividing wall tower 2 from top to bottom into a common rectifying section 101, a pre-fractionation section 102, an intermediate component product extraction section 103 and a common stripping section 104, wherein the pre-fractionation section 102 and the intermediate component product extraction section 103 are separated by the middle partition 8, the common rectifying section 101 is provided in the upper space of the middle partition 8, and the common stripping section 104 is provided in the lower space of the middle partition 8;

[0042] The dividing wall tower 2 is provided with a raw material feed port 9, a first extraction port 12, a second extraction port 10 and a third extraction port 11. The raw material feed port 9 is provided in the middle of the pre-fractionation section 102 to divide the pre-fractionation section 102 into a pre-rectification section and a pre-stripping section; the first extraction port 12 is provided in the middle of the intermediate component product extraction section 103 to divide the intermediate component product extraction section 103 into a product rectification section and a product stripping section; the second extraction port 10 is provided at the top of the dividing wall tower 2, and the third extraction port 11 is provided at the bottom of the dividing wall tower 2;

[0043] A condensation reflux unit, the condensation reflux unit is arranged between the second production port 10 and the dividing wall tower 2, the condensation reflux unit is connected to the second production port 10, the feed port of the condensation reflux unit is connected to the top of the common distillation section 101, and the discharge port of the condensation reflux unit is connected to one side of the common distillation section 101;

[0044] The reboiler 6 is provided between the dividing wall tower 2 and the third production port 11, the reboiler unit is connected to the third production port 11, the feed port of the reboiler 6 is connected to one side of the common distillation section 104, and the discharge port of the reboiler 6 is connected to the bottom of the common distillation section 104.

[0045] In some optional embodiments, the condensation reflux unit also includes a top reflux tank 4, a condenser 3 and a reflux pump 5, the feed port of the condenser 3 is connected to the top of the common distillation section 101, the discharge port of the condenser 3 is connected to the top reflux tank 4, the discharge port of the top reflux tank 4 is connected to the reflux pump 5, the discharge port of the reflux pump 5 is connected to one side of the common distillation section 101, and the discharge port of the reflux pump 5 is also connected to the second production port 10.

[0046] In the embodiment of the present application, the specific components of the control condensation reflux unit are a tower top reflux tank 4, a condenser 3 and a reflux pump 5. The C4 and isopentane components separated from the common distillation section 101 can be condensed by the condenser 3, and the condensed components are stored through the tower top reflux tank 4. At the same time, a part of the liquid phase at the bottom of the tower top reflux tank 4 is used as C4 and isopentane component products, and the rest is returned to the common distillation section 101 as reflux, thereby ensuring that high-purity C4 and isopentane component products are obtained.

[0047] In some optional embodiments, the common distillation section 101 is further provided with a partition plate 7 to distinguish the feed inlet and the discharge outlet of the condensation reflux unit.

[0048] In the embodiment of the present application, by providing a partition plate 7 in the common distillation section 101, it is possible to ensure that the feed inlet and the discharge outlet of the condensation reflux unit are separated, thereby ensuring the condensation effect of the condensation reflux unit.

[0049] In some optional embodiments, the processing system further comprises:

[0050] The distribution control unit 13 includes a first pipeline 131, a second pipeline 132 and a third pipeline 133, wherein one end of the first pipeline 131 is connected to one side of the common distillation section 101, and the other end of the first pipeline 131 is connected to one side of the second pipeline 132; the feed port of the second pipeline 132 is connected to one side of the common distillation section 101, and the discharge port of the second pipeline 132 is connected to the feed port of the pre-fractionation section 102; one end of the third pipeline 133 is connected to one side of the common distillation section 101, and the other end of the third pipeline 133 is connected to the intermediate component product extraction section 103.

[0051] In the embodiment of the present application, by introducing a distribution control unit 13 into the processing system, the first pipeline 131, the second pipeline 132 and the third pipeline 133 of the distribution control unit 13 are used to complete the reasonable distribution of the liquid phase in the pre-fractionation section 102 and the intermediate component product extraction section 103, thereby ensuring the distillation quality of the final isomerization raw material product.

[0052] In some optional embodiments, the allocation control unit 13 further includes a fourth pipeline 134 , one end of the fourth pipeline 134 is connected to the intermediate component product extraction section 103 , and the other end of the fourth pipeline 134 is connected to one side of the common distillation section 104 .

[0053] In the embodiment of the present application, the fourth pipeline 134 is introduced into the distribution control unit 13, and the isomerized raw material product of the intermediate component product extraction section 103 is introduced into the common distillation section 104 by the fourth pipeline 134, so that the benzene and C7+ heavy component materials in the isomerized raw material product are separated in the common distillation section, thereby ensuring that a high-purity isomerized raw material product is obtained.

[0054] In some optional embodiments, the processing system also includes a feed heat exchanger 1, the feed heat exchanger 1 is connected to the raw material feed port 9, one end of the feed heat exchanger 1 is connected to the pre-fractionation section 102, one end of the feed heat exchanger 1 is connected to the common stripping section 104, and the feed heat exchanger 1 is provided with a product discharge port.

[0055] In the embodiment of the present application, a feed heat exchanger 1 is introduced into the processing system, and the feed heat exchanger 1 is used to ensure that the heat of the light naphtha can be applied to the isomerization reaction part, thereby further reducing the heat consumed by the processing system and reducing the energy medium consumption of the isomerization raw material processing.

[0056] In some optional embodiments, the dividing wall tower 2 has 80 to 130 plates.

[0057] In the embodiment of the present application, the specific number of plates of the bulkhead tower 2 is controlled to ensure that the bulkhead tower 2 is divided into a common distillation section 101, a pre-fractionation section 102, an intermediate component product extraction section 103 and a common stripping section 104, thereby preventing the remixing of the separated components. Together with the condensation reflux unit and the reboiler 6, the amount of condensation and reheating required to reduce the reflux amount of the components can be achieved, so that a large amount of isomerized raw material products can be accumulated in the intermediate component product extraction section 103, thereby improving the processing efficiency of the isomerized raw materials.

[0058] In some optional embodiments, the number of trays of the common distillation section 101 is 20 to 40; and / or,

[0059] The number of the plates of the pre-fractionation section 102 is 20 to 30; and / or,

[0060] The number of trays in the intermediate component product extraction section 103 is 40 to 55; and / or,

[0061] The number of plates of the common stripping section 104 is 20 to 50; and / or,

[0062] The number of the intermediate partition plates 8 is 20 to 25.

[0063] In the embodiment of the present application, the sum of the number of plates of the pre-fractionation section 102 and the middle partition 8 is the same as the number of plates of the intermediate component product extraction section 103 .

[0064] The specific number of plates in the common distillation section 101, the pre-fractionation section 102, the intermediate component product extraction section 103 and the common stripping section 104 is controlled to ensure smooth operation of each stage, while preventing remixing of the separated components and ensuring the purity of the isomerized raw material after treatment.

[0065] In some optional embodiments, the operating pressure of the dividing wall tower 2 is 0.2 MPa to 0.5 MPa.

[0066] In the embodiment of the present application, controlling the specific operating pressure of the bulkhead tower 2 can ensure the normal operation of each area of ​​the common distillation section 101, the pre-fractionation section 102, the intermediate component product extraction section 103 and the common stripping section 104 in the bulkhead tower 2, thereby ensuring the purity of the isomerized raw material after treatment.

[0067] The operating pressure of the dividing wall tower can be 0.25 MPa to 0.3 MPa.

[0068] like Figure 2 As shown, based on a general inventive concept, the present application provides a method for processing light hydrocarbon isomerization feedstock, the processing method is adapted to the processing system, and the processing method includes:

[0069] S1. Heat exchange is performed on the light naphtha raw material, followed by pre-fractionation and intermediate component product extraction to obtain a first component and a second component, respectively;

[0070] S2. The second component is subjected to common distillation, followed by condensation and reflux to obtain C4 and isopentane component products;

[0071] S3. The first component is subjected to reboiling and common distillation to obtain benzene and C7 + heavy component materials and isomerization feedstock respectively;

[0072] S4. performing heat exchange on the isomerization feedstock to utilize the heat exchange amount of the light naphtha feedstock to perform an isomerization reaction to obtain an isomerization feedstock product.

[0073] The method is implemented based on the above system. The specific composition of the system can refer to the above embodiment. Since the method adopts part or all of the technical solutions of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment, which will not be described one by one here.

[0074] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0075] Example 1

[0076] like Figure 1 As shown, a processing system for light hydrocarbon isomerization feedstock comprises:

[0077] A dividing wall tower 2, wherein a middle partition 8 is provided in the middle of the dividing wall tower 2 to divide the dividing wall tower 2 from top to bottom into a common rectifying section 101, a pre-fractionation section 102, an intermediate component product extraction section 103 and a common stripping section 104, wherein the pre-fractionation section 102 and the intermediate component product extraction section 103 are separated by the middle partition 8, the common rectifying section 101 is provided in the upper space of the middle partition 8, and the common stripping section 104 is provided in the lower space of the middle partition 8;

[0078] The dividing wall tower 2 is provided with a raw material feed port 9, a first extraction port 12, a second extraction port 10 and a third extraction port 11. The raw material feed port 9 is provided in the middle of the pre-fractionation section 102 to divide the pre-fractionation section 102 into a pre-rectification section and a pre-stripping section; the first extraction port 12 is provided in the middle of the intermediate component product extraction section 103 to divide the intermediate component product extraction section 103 into a product rectification section and a product stripping section; the second extraction port 10 is provided at the top of the dividing wall tower 2, and the third extraction port 11 is provided at the bottom of the dividing wall tower 2;

[0079] A condensation reflux unit, which is disposed between the second production port 10 and the dividing wall tower 2, the condensation reflux unit is connected to the second production port 10, the feed port of the condensation reflux unit is connected to the top of the common distillation section 101, and the discharge port of the condensation reflux unit is connected to one side of the common distillation section 101;

[0080] The reboiler 6 is arranged between the dividing wall tower 2 and the third production port 11 , the reboiler unit is connected to the third production port 11 , the feed port of the reboiler 6 is connected to one side of the common distillation section 104 , and the discharge port of the reboiler 6 is connected to the bottom of the common distillation section 104 .

[0081] The condensation reflux unit also includes a tower top reflux tank 4, a condenser 3 and a reflux pump 5, the feed port of the condenser 3 is connected to the top of the common distillation section 101, the discharge port of the condenser 3 is connected to the tower top reflux tank 4, the discharge port of the tower top reflux tank 4 is connected to the reflux pump 5, the discharge port of the reflux pump 5 is connected to one side of the common distillation section 101, and the discharge port of the reflux pump 5 is also connected to the second production port 10.

[0082] The common rectification section 101 is also provided with a partition plate 7 to distinguish the feed inlet and the discharge outlet of the condensation reflux unit.

[0083] The processing system also includes:

[0084] The distribution control unit 13 includes a first pipeline 131, a second pipeline 132 and a third pipeline 133. One end of the first pipeline 131 is connected to one side of the common distillation section 101, and the other end of the first pipeline 131 is connected to one side of the second pipeline 132; the feed port of the second pipeline 132 is connected to one side of the common distillation section 101, and the discharge port of the second pipeline 132 is connected to the feed port of the pre-fractionation section 102; one end of the third pipeline 133 is connected to one side of the common distillation section 101, and the other end of the third pipeline 133 is connected to the intermediate component product extraction section 103.

[0085] The distribution control unit 13 further includes a fourth pipeline 134 , one end of which is connected to the intermediate component product extraction section 103 , and the other end of the fourth pipeline 134 is connected to one side of the common distillation section 104 .

[0086] The processing system also includes a feed heat exchanger 1, which is connected to a raw material feed port 9, one end of which is connected to a pre-fractionation section 102, one end of which is connected to a common stripping section 104, and a product discharge port is provided in the feed heat exchanger 1.

[0087] The number of plates of the bulkhead column 2 is 120.

[0088] The number of plates of the middle partition 8 is 20;

[0089] The number of trays in the common distillation section 101 is 30;

[0090] The number of trays in the pre-fractionation section 102 is 30;

[0091] The number of trays in the intermediate component product extraction section 103 is 50;

[0092] The number of trays in the common stripping section 104 is 40;

[0093] The operating pressure of the dividing wall column 2 is 0.24 MPa.

[0094] The chemical composition of the light naphtha raw material used is shown in Table 1.

[0095] Table 1 Composition of light naphtha raw materials

[0096]

[0097]

[0098] Example 2

[0099] Comparing Example 2 with Example 1, the difference between Example 2 and Example 1 is:

[0100] The dividing wall column 2 has 130 plates.

[0101] The number of trays in the common distillation section 101 is 40;

[0102] The number of trays in the pre-fractionation section 102 is 30;

[0103] The number of trays in the intermediate component product extraction section 103 is 55;

[0104] The number of trays in the common stripping section 104 is 35;

[0105] The number of the intermediate partition plates 8 is 25.

[0106] The operating pressure of the dividing wall tower is 0.2 MPa.

[0107] Example 3

[0108] Comparing Example 3 with Example 1, the difference between Example 3 and Example 1 is:

[0109] The number of plates in the dividing wall column 2 is 80

[0110] The number of trays in the common distillation section 101 is 20;

[0111] The number of trays in the pre-fractionation section 102 is 20;

[0112] The number of trays in the intermediate component product extraction section 103 is 40;

[0113] The number of trays in the common stripping section 104 is 20;

[0114] The number of the intermediate partition plates 8 is 20.

[0115] The operating pressure of the dividing wall tower is 0.5 MPa.

[0116] Comparative Example 1

[0117] Comparative Example 1 and Example 1 are compared. The difference between Comparative Example 1 and Example 1 is:

[0118] Use Figure 3 The side column shown processes a light naphtha feedstock.

[0119] Comparative Example 2

[0120] Comparative Example 2 and Example 1 are compared. The difference between Comparative Example 2 and Example 1 is:

[0121] Use Figure 4 The two-tower method for removing light and heavy substances is shown for treating light naphtha feedstock.

[0122] Related experiments and effect data:

[0123] Taking the processing capacity of 400,000 tons / year of light naphtha as an example, the changes in the processing process of the light naphtha raw material in Example 1, Comparative Example 1 and Comparative Example 2 were statistically analyzed, and the results are shown in Table 2.

[0124] Table 2 Comparison of the treatment process of light naphtha raw materials in the embodiment and the comparative example

[0125] project Comparative Example 2 Comparative Example 1 Example 1 Number of plates 60 / 60 85 120 Tower top pressure (MPa) 0.24 / 0.24 0.24 0.24 Light naphtha feed rate (kmol / h) 629.3 629.3 629.3 C4 and isopentane product amount (kmol / h) 220.4 222.4 220.4 Isomerization raw material product amount (kmol / h) 355.3 375 355.3 Benzene and C7+ heavy components production (kmol / h) 53.6 31.9 53.6 C4 and isopentane product purity (% mol) 98 97.5 98 Isomerization raw material product purity (% mol) 95 80 95 Purity of benzene and C7+ heavy components (mol%) 98 98 98 Benzene content of isomerization raw material product (% mol) 1.35 3.3 1.52 Reboiler heat load (MW) 13.6 / 18.8 28.2 24.0 Reboiler heat load comparison 1.35 1.175 Benchmark 1

[0126] As can be seen from Table 2, the system of the present application can obtain a normal alkane component with a content of more than 95% mol, and the reboiler load is reduced by 17.5%, the normal alkane content in the isomerization feedstock is increased by 15%, and the benzene content is reduced by more than 1 times, which can greatly reduce the temperature rise of the isomerization reactor, which is beneficial to improve the isomerization conversion rate.

[0127] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0128] (1) A processing system for light hydrocarbon isomerization feedstock provided in an embodiment of the present application has a bulkhead tower which is a thermodynamically ideal system structure. It avoids the formation of entropy mixing between the feed and the feed tray due to the difference in component composition, and also avoids the back-mixing effect of the intermediate components. It has a high separation efficiency, and the gas phase flow rate in the tower is smaller than the total gas phase volume in a conventional two-tower process. For a given material, to complete the same separation task, the bulkhead tower requires less reboil heat and condensation than the conventional two-tower process or the side-line extraction process, and the utility consumption is reduced by more than 30%.

[0129] (2) The embodiment of the present application provides a processing system for isomerization of light hydrocarbons. It is difficult to achieve high purity by extracting the intermediate component product from the side line of a traditional distillation tower. However, after adopting a dividing wall tower, the feed and product extraction are separated by an intermediate partition, which prevents the remixing of the separated components, so that the purity of the extracted isomerization raw material product (C5-C6 normal components) can reach more than 95%, while the purity of the isomerization raw material product (C5-C6 normal components) extracted from the side line extraction tower cannot exceed 80%, otherwise the tower will require a larger reflux volume, and the reboiler 6 and the condenser 3 will require a larger reboil heat and condensation volume. At the same time, isomerization is a concentration equilibrium reaction. The higher the content of normal alkane components in the isomerization raw material, the more conducive it is to the conversion of alkane isomerization. In addition, the equipment size and catalyst amount are reduced, saving investment.

[0130] (3) The embodiment of the present application provides a processing system for light hydrocarbon isomerization feedstock. Compared with the traditional two-tower series process for removing light and heavy wastes, the system adopts a bulkhead tower process. The number of major equipment is reduced by half, and the diameter of the bulkhead tower is smaller than the diameter of the largest tower in the two-tower series process. Therefore, the investment cost can be greatly reduced. The total equipment investment can be saved by about 20%, and the larger the scale, the more obvious the saving effect.

[0131] (4) The embodiment of the present application provides a processing system for light hydrocarbon isomerization feedstock, which improves the purity of normal alkanes in the isomerization feedstock, is beneficial to improving the isomerization conversion rate, and reduces the investment in isomerization equipment and catalysts; at the same time, compared with the traditional two-tower de-lightening and de-heavyening towers, the energy consumption of the device can be reduced by more than 30%, greatly reducing the steam consumption of the reboiler 6, saving operating costs, reducing carbon emissions, and improving the economic benefits of the refinery.

[0132] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0133] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0134] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A system for processing light hydrocarbon isomerization feedstock, characterized in that: The processing system comprises: A dividing wall tower (2), wherein a middle partition (8) is provided in the middle of the dividing wall tower (2) to divide the dividing wall tower (2) from top to bottom into a common rectifying section (101), a pre-fractionation section (102), an intermediate component product extraction section (103) and a common stripping section (104), wherein the pre-fractionation section (102) and the intermediate component product extraction section (103) are separated by the middle partition (8), the common rectifying section (101) is provided in the upper space of the middle partition (8), and the common stripping section (104) is provided in the lower space of the middle partition (8); The dividing wall tower (2) is provided with a raw material feed port (9), a first extraction port (12), a second extraction port (10) and a third extraction port (11); the raw material feed port (9) is arranged in the middle of the pre-fractionation section (102) to divide the pre-fractionation section (102) into a pre-rectification section and a pre-stripping section; the first extraction port (12) is arranged in the middle of the intermediate component product extraction section (103) to divide the intermediate component product extraction section (103) into a product rectification section and a product stripping section; the second extraction port (10) is arranged at the top of the dividing wall tower (2), and the third extraction port (11) is arranged at the bottom of the dividing wall tower (2); A condensation reflux unit, the condensation reflux unit being arranged between the second production outlet (10) and the dividing wall tower (2), the condensation reflux unit being connected to the second production outlet (10), the feed inlet of the condensation reflux unit being connected to the top of the common distillation section (101), and the discharge outlet of the condensation reflux unit being connected to one side of the common distillation section (101); A reboiler (6), wherein the reboiler (6) is arranged between the dividing wall tower (2) and the third production outlet (11), the reboiler unit is connected to the third production outlet (11), the feed port of the reboiler (6) is connected to one side of the common distillation section (104), and the discharge port of the reboiler (6) is connected to the bottom of the common distillation section (104).

2. The processing system according to claim 1, characterized in that The condensation reflux unit further comprises a tower top reflux tank (4), a condenser (3) and a reflux pump (5), wherein the feed port of the condenser (3) is connected to the top of the common distillation section (101), the discharge port of the condenser (3) is connected to the tower top reflux tank (4), the discharge port of the tower top reflux tank (4) is connected to the reflux pump (5), the discharge port of the reflux pump (5) is connected to one side of the common distillation section (101), and the discharge port of the reflux pump (5) is also connected to the second production port (10).

3. The processing system according to claim 1, characterized in that The common rectification section (101) is also provided with a partition plate (7) to distinguish the feed inlet and the discharge outlet of the condensation reflux unit.

4. The processing system according to claim 1, characterized in that The processing system further comprises: A distribution control unit (13), the distribution control unit (13) comprising a first pipeline (131), a second pipeline (132) and a third pipeline (133), one end of the first pipeline (131) being connected to one side of the common distillation section (101), and the other end of the first pipeline (131) being connected to one side of the second pipeline (132); a feed port of the second pipeline (132) being connected to one side of the common distillation section (101), and a discharge port of the second pipeline (132) being connected to a feed port of the pre-fractionation section (102); one end of the third pipeline (133) being connected to one side of the common distillation section (101), and the other end of the third pipeline (133) being connected to the intermediate component product extraction section (103).

5. The processing system according to claim 4, characterized in that The distribution control unit (13) further comprises a fourth pipeline (134), one end of which is connected to the intermediate component product extraction section (103), and the other end of which is connected to one side of the common distillation section (104).

6. The processing system according to claim 4, characterized in that The processing system further comprises a feed heat exchanger (1), wherein the feed heat exchanger (1) is connected to the raw material feed port (9), one end of the feed heat exchanger (1) is connected to the pre-fractionation section (102), one end of the feed heat exchanger (1) is connected to the common stripping section (104), and the feed heat exchanger (1) is provided with a product discharge port.

7. The processing system according to claim 1, characterized in that The number of plates of the dividing wall column (2) is 80 to 130.

8. The processing system according to claim 7, characterized in that The number of plates of the common distillation section (101) is 20 to 40; and / or, The number of the trays in the pre-fractionation section (102) is 20 to 30; and / or, The number of trays in the intermediate component product extraction section (103) is 40 to 55; and / or, The number of trays of the common stripping section (104) is 20 to 50; and / or, The number of the intermediate partition plates (8) is 20 to 25.

9. The processing system according to claim 1, characterized in that The operating pressure of the dividing wall tower is 0.2MPa to 0.5MPa.

10. A method for treating a light hydrocarbon isomerization feedstock, characterized in that: The processing method is adapted to the processing system according to any one of claims 1 to 9, and the processing method comprises: Heat exchange is performed on the light naphtha raw material, followed by pre-fractionation and intermediate component product extraction to obtain a first component and a second component respectively; The second component is subjected to common distillation, followed by condensation and reflux to obtain C4 and isopentane component products; Reboiling and stripping the first component to obtain benzene and C7+ heavy component materials and isomerization raw materials respectively; The isomerization feedstock is heat exchanged to utilize the heat exchange amount of the light naphtha feedstock to perform an isomerization reaction to obtain an isomerization feedstock product.

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