Isohexane removal circulating system

Abstract

The invention relates to a deisohexane circulating system, which comprises a deisohexane tower, a deisohexane tower, a deisohexane tower, a deisohexane tower, a deisohexane tower, a deisohexane tower, a deisohexane tower, a deisohexane tower, a deisohexane tower, a deisohexane tower and a deisohexane tower, the circulating pump is communicated with the circulating material inlet; the isomerization reaction system is communicated with the circulating pump; the heat exchanger is communicated with the circulating pump and the deisohexane tower; the feeding pipe is communicated with the isomerization reaction system and the heat exchanger, and the heat exchanger is further communicated with the raw material inlet; and the reboiler is communicated with the lower part of the isohexane removal tower. By additionally arranging the heat exchanger, the material pumped out by the circulating pump is divided into two parts, one part enters the isomerization reaction system for further octane number increase, and the other part is recycled back to the deisohexane tower after being subjected to heat exchange through the heat exchanger, so that the gas-liquid load below the circulating material outlet is greatly reduced; therefore, the load of the reboiler is reduced, and the energy consumption of the isohexane removal tower is reduced.

Description

Technical Field

[0001] The present application relates to the field of petrochemical industry, and in particular to isohexane. Background Art

[0002] The rapid development of automobile engine industry technology and increasingly stringent environmental protection requirements have put forward higher requirements for the production of clean fuels, requiring gasoline to be low in sulfur, low in olefins, low in benzene, and low in aromatics, while the octane number remains unchanged. Olefins and aromatics are components with higher octane numbers in motor gasoline. The reduction of their content will inevitably lead to a decrease in octane number. If the octane number remains unchanged, it is necessary to blend high-octane components. Alkane isomerization technology is an important measure for refineries to produce environmentally friendly clean gasoline. Its product, isomerized oil, is an environmentally friendly clean gasoline component that does not contain sulfur, olefins, or aromatics and has a higher octane number.

[0003] The octane number of light petroleum is relatively low, generally 60-70. In order to prepare high-octane isomerized gasoline, that is, isomerized gasoline with an octane number RON of 88 or above, a deisohexanization circulation process is required, that is, the reaction products from the reactor are separated into high and low octane components in the deisohexanizer, and the low-octane isoparaffins and unreacted normal paraffins are recycled back to the isomerization reactor for further conversion. The high-octane isomerized gasoline component produced at the top of the traditional deisohexanizer and the heavy gasoline component at the bottom of the tower are mixed as products. The low-octane isoparaffins and unreacted normal paraffins are extracted from the side line of the tower and directly recycled to the isomerization reaction for octane number improvement. Due to the logistics cycle and side line extraction, the steam consumption of the deisohexanizer is large and the energy consumption is high. Summary of the invention

[0004] The embodiment of the present application provides a deisohexane circulation system to solve the technical problem of high energy consumption of the deisohexane tower.

[0005] The present application embodiment provides a deisohexane circulation system, the deisohexane circulation system comprising:

[0006] A deisohexanizer, wherein the upper portion of the deisohexanizer is provided with a raw material inlet, and the middle portion is provided with a circulating material inlet and a circulating material outlet, wherein the circulating material outlet is provided above the circulating material inlet;

[0007] A circulation pump connected to the circulation material inlet;

[0008] An isomerization reaction system, connected to the circulation pump;

[0009] A heat exchanger, the heat exchanger is connected to the circulation pump and the deisohexanizer, a part of the material pumped by the circulation pump enters the isomerization reaction system, and the other part enters the circulation material inlet after heat exchange by the heat exchanger;

[0010] A feed pipe, the feed pipe is connected to the isomerization reaction system and the heat exchanger, the heat exchanger is also connected to the raw material inlet, the feed pipe inputs the isomerization reaction product prepared by the isomerization reaction system into the heat exchanger for heat exchange, and the isomerization reaction product enters the raw material inlet after heat exchange;

[0011] A reboiler is connected to the lower part of the deisohexane tower.

[0012] In some embodiments of the present application, the de-isohexane circulation system further includes a circulation buffer tank, and the circulation pump is connected to the circulation material outlet through the circulation buffer tank.

[0013] In some embodiments of the present application, the de-isohexane circulation system further includes a product output pipe, and the product output pipe is connected to the top end and the bottom end of the de-isohexane tower.

[0014] In some embodiments of the present application, a product cooler is provided on the product output pipe.

[0015] In some embodiments of the present application, the de-isohexane circulation system further includes an output pump, and the product output pipe is connected to the bottom end of the de-isohexane tower through the output pump.

[0016] In some embodiments of the present application, the deisohexane circulation system further comprises:

[0017] A tower top cooler, the tower top cooler being in communication with the top of the deisohexane tower;

[0018] A reflux pump is connected to the tower top cooler, and the reflux pump is also connected to the upper part of the deisohexane tower.

[0019] In some embodiments of the present application, the reflux pump is also connected to the product output pipe.

[0020] In some embodiments of the present application, the de-isohexane circulation system further includes a reflux drum, and the reflux pump is connected to the tower top cooler through the reflux drum.

[0021] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0022] The de-isohexanizing circulation system provided in the embodiment of the present application is provided with a heat exchanger, and the material pumped out by the circulation pump is divided into two parts, one part enters the isomerization reaction system for further octane number improvement, and the other part is circulated back to the de-isohexanizing tower after heat exchange in the heat exchanger, and the circulation material outlet is arranged above the circulation material inlet, so that the gas-liquid load balance in the de-isohexanizing tower is changed, the gas phase amount above the circulation material outlet is increased, and the liquid phase amount below the circulation material outlet is reduced, so that the gas-liquid load below the circulation material outlet is greatly reduced, thereby reducing the load of the reboiler and reducing the energy consumption of the de-isohexanizing tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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.

[0024] 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.

[0025] Figure 1 A schematic diagram of the structure of a deisohexane circulation system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] 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.

[0027] Unless otherwise specified, the terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. In the event of a conflict, this specification takes precedence.

[0028] 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.

[0029] The existing deisohexanizer has the technical problem of high energy consumption.

[0030] In order to solve the above technical problems, the present application embodiment provides a deisohexane circulation system, please refer to Figure 1 , the deisohexane circulation system comprises:

[0031] A deisohexanizer 1, wherein the upper portion of the deisohexanizer 1 is provided with a raw material inlet, and the middle portion is provided with a circulating material inlet and a circulating material outlet, wherein the circulating material outlet is provided above the circulating material inlet;

[0032] A circulation pump 9, connected to the circulation material inlet;

[0033] An isomerization reaction system 11, connected to the circulation pump 9;

[0034] A heat exchanger 10, wherein the heat exchanger 10 is connected to the circulation pump 9 and the deisohexanizer 1, a part of the material pumped by the circulation pump 9 enters the isomerization reaction system 11, and the other part enters the circulation material inlet after heat exchange in the heat exchanger 10;

[0035] A feed pipe, the feed pipe is connected to the isomerization reaction system 11 and the heat exchanger 10, the heat exchanger 10 is also connected to the raw material inlet, the feed pipe inputs the isomerization reaction product prepared by the isomerization reaction system 11 into the heat exchanger 10 for heat exchange, and the isomerization reaction product enters the raw material inlet after heat exchange;

[0036] The reboiler 6 is connected to the lower part of the deisohexanizing tower 1.

[0037] Those skilled in the art can understand that the top of the deisohexanizer 1 produces a high-octane isomerized gasoline component, and the bottom produces a heavy gasoline component. Low-octane isoparaffins and unreacted normal paraffins are extracted from the circulating material inlet by the circulating pump 9, and then enter the isomerization reaction system 11 to increase the octane number again. The isomerization reaction system 11 is a conventional chemical reaction system in the art, and the present application is implemented in accordance with the conventional manner in the art.

[0038] There are two streams of logistics in the heat exchanger 10 for heat exchange with each other. One stream is the raw material introduced by the feed pipe. The raw material enters the raw material inlet after heat exchange in the heat exchanger 10. Those skilled in the art can understand that the temperature of the raw material before entering the heat exchanger 10 is about 170-180°C; the other stream is the circulating material drawn out by the circulating pump 9. The circulating pump 9 pumps the circulating material into the heat exchanger 10 for heat exchange and then enters the circulating material inlet. Those skilled in the art can understand that the temperature of the circulating material before entering the heat exchanger 10 is about 95-105°C. It can be seen that the heat exchange process is a process in which the raw material releases heat and the circulating material absorbs heat. In practical applications, after heat exchange in the heat exchanger, the temperature of the raw material generally reaches 135-145°C, and the temperature of the circulating material generally reaches 100-110°C.

[0039] The material pumped out by the circulation pump 9 is divided into two parts. One part enters the isomerization reaction system 11 for further octane number improvement, which reduces the total amount of material in the de-isohexanizer 1; the other part is heated by the heat exchanger 10, and its temperature is increased, and then it is recycled back to the de-isohexanizer 1. The circulation material outlet is arranged above the circulation material inlet, which increases the temperature of the material below the circulation material outlet, thereby reducing its liquid phase amount, thereby reducing the load of the reboiler 6.

[0040] Compared with the traditional solution, the present application adds a heat exchanger 10, and the material pumped out by the circulation pump 9 is divided into two parts, one part enters the isomerization reaction system 11 for further octane number improvement, and the other part is circulated back to the de-isohexanizer 1 after heat exchange in the heat exchanger 10, and the circulation material outlet is arranged above the circulation material inlet, so that the gas-liquid load balance in the de-isohexanizer 1 is changed, the gas phase amount above the circulation material outlet is increased, and the liquid phase amount below the circulation material outlet is reduced, so that the gas-liquid load below the circulation material outlet is greatly reduced, thereby reducing the load of the reboiler 6 and reducing the energy consumption of the de-isohexanizer 1.

[0041] In addition, the heat exchanger 10 can increase the temperature of the raw materials introduced by the feed pipe and reduce the overall energy consumption; the gas and liquid loads below the circulating material outlet are greatly reduced, which makes it possible to further reduce the diameter of the de-isohexanizer 1 below the circulating material outlet, saving equipment investment.

[0042] In some embodiments of the present application, the de-isohexane circulation system further includes a circulation buffer tank 8 , and the circulation pump 9 is connected to the circulation material outlet through the circulation buffer tank 8 .

[0043] The circulating material led out from the circulating material outlet first enters the circulating buffer tank 8, and the circulating pump 9 extracts the circulating material in the circulating buffer tank 8. The circulating buffer tank 8 can play a buffering role.

[0044] In some embodiments of the present application, the de-isohexane circulation system further includes a product output pipe, and the product output pipe is connected to the top end and the bottom end of the de-isohexane tower 1.

[0045] Those skilled in the art will appreciate that the top of the deisohexanizer 1 produces a high-octane isomerized gasoline component, and the bottom produces a heavy gasoline component. It is a common practice in the art to combine the high-octane isomerized gasoline component and the heavy gasoline component and output them as a product.

[0046] In some embodiments of the present application, a product cooler 5 is provided on the product output pipe.

[0047] The function of the product cooler 5 is to cool the product before it is output, so as to facilitate the collection of the product and reduce the volatilization loss of the product after it is output.

[0048] In some embodiments of the present application, the de-isohexane circulation system further includes an output pump 7 , and the product output pipe is connected to the bottom end of the de-isohexane tower 1 through the output pump 7 .

[0049] The output pump 7 provides power for outputting the heavy gasoline component produced at the bottom end of the deisohexanizer 1 .

[0050] In some embodiments of the present application, the deisohexane circulation system further comprises:

[0051] A tower top cooler 2, wherein the tower top cooler 2 is connected to the top of the deisohexane tower 1;

[0052] A reflux pump 4 is connected to the tower top cooler 2 , and the reflux pump 4 is also connected to the upper part of the de-isohexane tower 1 .

[0053] In some embodiments of the present application, the reflux pump 4 is also connected to the product output pipe.

[0054] Those skilled in the art will appreciate that after the high-octane isomerized gasoline component produced at the top of the deisohexanizer 1 is cooled by the top cooler 2, a portion of it is pumped back to the deisohexanizer 1 through the reflux pump 4, and the other portion is output through the product output pipe. The purpose of pumping a portion of the high-octane isomerized gasoline component back to the deisohexanizer 1 is to further remove the low-octane component therein.

[0055] In some embodiments of the present application, the de-isohexane circulation system further includes a reflux drum 3 , and the reflux pump 4 is connected to the tower top cooler 2 through the reflux drum 3 .

[0056] The reflux tank 3 is used to store the high-octane isomerized gasoline component cooled by the tower top cooler 2 and plays a buffering role.

[0057] 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.

[0058] Example

[0059] This embodiment provides a deisohexane circulation system, please refer to Figure 1 , the deisohexane circulation system comprises:

[0060] A deisohexanizer 1, wherein the upper portion of the deisohexanizer 1 is provided with a raw material inlet, and the middle portion is provided with a circulating material inlet and a circulating material outlet, wherein the circulating material outlet is provided above the circulating material inlet;

[0061] A circulation pump 9, connected to the circulation material inlet;

[0062] An isomerization reaction system 11, connected to the circulation pump 9;

[0063] A heat exchanger 10, wherein the heat exchanger 10 is connected to the circulation pump 9 and the deisohexanizer 1, a part of the material pumped by the circulation pump 9 enters the isomerization reaction system 11, and the other part enters the circulation material inlet after heat exchange in the heat exchanger 10;

[0064] A feed pipe, the feed pipe is connected to the isomerization reaction system 11 and the heat exchanger 10, the heat exchanger 10 is also connected to the raw material inlet, the feed pipe inputs the isomerization reaction product prepared by the isomerization reaction system 11 into the heat exchanger 10 for heat exchange, and the isomerization reaction product enters the raw material inlet after heat exchange;

[0065] The reboiler 6 is connected to the lower part of the deisohexanizing tower 1.

[0066] The deisohexane circulation system further includes a circulation buffer tank 8 , and the circulation pump 9 is connected to the circulation material outlet through the circulation buffer tank 8 .

[0067] The deisohexane circulation system further comprises a product output pipe, which is connected to the top and bottom of the deisohexane tower 1 .

[0068] A product cooler 5 is provided on the product output pipe.

[0069] The deisohexane circulation system further includes an output pump 7 , and the product output pipe is connected to the bottom end of the deisohexane tower 1 through the output pump 7 .

[0070] The deisohexane circulation system also includes:

[0071] A tower top cooler 2, wherein the tower top cooler 2 is connected to the top of the deisohexane tower 1;

[0072] A reflux pump 4 is connected to the tower top cooler 2 , and the reflux pump 4 is also connected to the upper part of the de-isohexane tower 1 .

[0073] The reflux pump 4 is also connected to the product output pipe.

[0074] The deisohexane circulation system further includes a reflux tank 3 , and the reflux pump 4 is connected to the tower top cooler 2 through the reflux tank 3 .

[0075] Comparative Example

[0076] The difference between this comparative example and the embodiment is only that:

[0077] The deisohexane circulation system does not include a heat exchanger, and all connections related to the heat exchanger are cancelled accordingly;

[0078] The deisohexanizer is not provided with a circulating material inlet.

[0079] Related experiments and effect data:

[0080] The output of the de-isohexane circulation system provided in the embodiment and the comparative example is 400,000 tons / year. During the implementation, it is found that the de-isohexane circulation system provided in the embodiment has a 23.3% lower reboiler load than the comparative example, and the overall energy consumption is reduced by 6.5 kg standard oil / t feed. According to the National Standard for Carbon Emission Limits for Refining Unit Products (Draft for Comments), carbon emissions can be reduced by 8,243.3 tons per year.

[0081] The reboiler load data of the embodiments and comparative examples are shown in the following table:

[0082] project <![CDATA[Reboiler load (10 6 kcal / h)]]> Relative consumption (%) Example 16.04 100 Comparative Example 19.78 123.3

[0083] 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.

[0084] 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 application specification, the terms "including", "comprising", etc. refer to "including but not limited to". Moreover, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "including..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. 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 associated objects, indicating that there can 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. For the association relationship of more than three associated objects described by "and / or", it means that any one of these three associated objects can exist alone, or any at least two of them exist at the same time. For example, for A, and / or B, and / or C, it can be represented that any one of A, B, and C exists alone, or any two of them exist at the same time, or three of them exist at the same time. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single (individual) or plural (individual). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, wherein a, b, and c can be single or multiple, respectively.

[0085] 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 deisohexane circulation system, characterized in that: The deisohexane circulation system comprises: A deisohexanizer, wherein the upper portion of the deisohexanizer is provided with a raw material inlet, and the middle portion is provided with a circulating material inlet and a circulating material outlet, wherein the circulating material outlet is provided above the circulating material inlet; A circulation pump connected to the circulation material inlet; An isomerization reaction system, connected to the circulation pump; A heat exchanger, the heat exchanger is connected to the circulation pump and the deisohexanizer, a part of the material pumped by the circulation pump enters the isomerization reaction system, and the other part enters the circulation material inlet after heat exchange by the heat exchanger; A feed pipe, the feed pipe is connected to the isomerization reaction system and the heat exchanger, the heat exchanger is also connected to the raw material inlet, the feed pipe inputs the isomerization reaction product prepared by the isomerization reaction system into the heat exchanger for heat exchange, and the isomerization reaction product enters the raw material inlet after heat exchange; A reboiler is connected to the lower part of the deisohexane tower.

2. The deisohexane circulation system according to claim 1, characterized in that: The deisohexane circulation system further comprises a circulation buffer tank, and the circulation pump is connected to the circulation material outlet through the circulation buffer tank.

3. The deisohexane circulation system according to claim 1, characterized in that: The deisohexane circulation system further comprises a product output pipe, which is connected to the top end and the bottom end of the deisohexane tower.

4. The deisohexane circulation system according to claim 3, characterized in that: A product cooler is arranged on the product output pipe.

5. The deisohexane circulation system according to claim 3, characterized in that: The deisohexane circulation system further comprises an output pump, and the product output pipe is connected to the bottom end of the deisohexane tower through the output pump.

6. The deisohexane circulation system according to claim 3, characterized in that: The deisohexane circulation system also includes: A tower top cooler, the tower top cooler being in communication with the top of the deisohexane tower; A reflux pump is connected to the tower top cooler, and the reflux pump is also connected to the upper part of the deisohexane tower.

7. The deisohexane circulation system according to claim 6, characterized in that: The reflux pump is also connected to the product output pipe.

8. The deisohexane circulation system according to claim 7, characterized in that: The deisohexane circulation system further comprises a reflux tank, and the reflux pump is connected with the tower top cooler through the reflux tank.

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