Ethylene oligomerization treatment heat recovery system

Abstract

The utility model discloses an ethylene oligomerization treatment heat recovery system, and relates to an ethylene oligomerization waste heat recovery device. Comprising a de-heavy tower, a reflux tank, a reaction product pipeline, a first heat exchanger and a de-heavy tower top pipeline, the de-heavy tower top is connected with the reflux tank through the de-heavy tower top pipeline, the de-heavy tower top pipeline is connected with one side of the first heat exchanger, and the reaction product pipeline is connected with the other side of the first heat exchanger. By utilizing the cooperation of the de-heavy tower top pipeline and the first heat exchanger, the material waste heat at 127 DEG C at the top of the de-heavy tower is fully utilized, so that the reflux temperature of the material at the top of the tower can be obviously reduced, the steam required by flash evaporation and impurity removal of the ethylene oligomerization product can be reduced, the energy consumption is reduced, and the dependence of the reflux of the material at the top of the de-heavy tower on an air cooler is reduced; and the construction and maintenance cost is reduced.

Description

Technical Field

[0001] The utility model relates to an ethylene polymerization waste heat recovery device, in particular to an ethylene polymerization treatment heat recovery system. Background Art

[0002] The technology of obtaining linear α-olefins and other straight-chain olefins through the polymerization reaction of ethylene has been widely used in the synthesis of advanced lubricant base oils, lubricant additives, olefin comonomers, as well as detergents, emulsifiers, flotation agents, adhesives and other fields.

[0003] The product obtained by the ethylene polymerization process generally needs to be flashed to flash out the unreacted ethylene. At this time, the temperature of the reaction product is about 65°C, and steam is needed to heat the temperature to 120°C, consuming a large amount of steam. In addition, the ethylene raw material and the final product also need to be deweighted to evaporate impurities, which also consumes a large amount of steam heat. And the top material discharged from the top of the deweighting tower must be cooled by a multi-stage air cooler before entering the top reflux tank to avoid affecting the reflux tank material and ensure the discharge efficiency of the deweighting tower material.

[0004] Therefore, the entire ethylene polymerization heat system requires a large amount of heat source supply, consumes energy, and has high requirements for air coolers. It requires high-temperature and high-efficiency air cooling equipment, has high construction costs, and causes large equipment losses. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide an ethylene polymerization treatment heat recovery system which can effectively reduce the heat consumption of ethylene polymerization process, improve production efficiency, reduce equipment loss and have low construction cost.

[0006] The utility model solves the technical problem by adopting the following technical solution: an ethylene polymerization treatment heat recovery system comprises a deweighting tower, a reflux tank and a deweighting tower top pipeline, wherein the deweighting tower top is connected to the reflux tank via the deweighting tower top pipeline, and is characterized in that it also comprises a reaction product pipeline and a first heat exchanger, wherein the deweighting tower top pipeline is connected to one side of the first heat exchanger, and the reaction product pipeline is connected to the other side of the first heat exchanger.

[0007] After the ethylene polymerization reaction product is released from the reactor, the unreacted ethylene needs to be flashed out by flash evaporation. At this time, the temperature of the reaction product is 65°C, and the product must be preheated to 120°C before flash evaporation. The first heat exchanger can utilize the waste heat of the top material of the deweighting tower (the temperature of the top material of the deweighting tower is generally 127°C), which can just be used to preheat the ethylene polymerization reaction product, which can not only significantly reduce the reflux temperature of the top material, but also reduce the steam required for preheating the ethylene polymerization product, thereby reducing energy consumption.

[0008] Preferably, a reflux pipeline is further included, and the reflux pipeline connects the top of the de-weighting tower and the reflux tank. The reflux pipeline provided is equivalent to adding a drainage channel to the top material of the de-weighting tower. The feed ratio of the reflux pipeline and the top pipeline of the de-weighting tower is set by the air cooler, which can effectively control the temperature of the material entering the reflux tank, and also can control the heating temperature of the first heat exchanger.

[0009] Further preferably, an air cooler is included, and the air cooler is arranged on the reflux line. The air cooler can cool the material in the reflux line. When the pressure in the reflux line is too high and the temperature of the reflux material is too high, the reflux material can be cooled by the air cooler. Due to the coordination between the deweighting tower top pipeline and the first heat exchanger, a single-stage low-temperature air cooler can be used to reduce the construction and maintenance costs of the air cooler.

[0010] Further preferably, a thermometer is provided on the air cooler.

[0011] Further preferably, a pressure gauge is provided between the reflux line and the top of the de-weighting tower, so as to facilitate the control of the feed ratio between the top pipeline of the de-weighting tower and the reflux line.

[0012] Preferably, it also includes a refining tower feed pipeline and a second heat exchanger, one side of the second heat exchanger is connected in parallel with the first heat exchanger on the deweighting tower top pipeline, and the refining tower feed pipeline is connected to the other side of the second heat exchanger.

[0013] Further preferably, a second switch is provided between one side of the second heat exchanger and the deweighting tower top pipeline.

[0014] Preferably, it also includes a refining tower bottom pipeline and a third heat exchanger, one side of the third heat exchanger is connected in parallel with the first heat exchanger on the deweighting tower top pipeline, and the refining tower bottom pipeline is connected to the other side of the third heat exchanger.

[0015] Further preferably, a third switch is provided between one side of the third heat exchanger and the deweighting tower top pipeline.

[0016] The boiling point of α-olefin is 63~65℃. When it is separated from mixed C6 in the distillation tower, the 127℃ de-weighting tower top material can provide a good and suitable heat source for the feed and the bottom of the tower to meet the operation of the distillation tower. The additional switches can effectively control the pressure of the de-weighting tower top material in the heat exchanger, and then control the heat exchange temperature and heat exchange effect.

[0017] Preferably, a first switch is provided between the first heat exchanger and the deweighting tower top pipeline, so as to more directly control the pressure of the deweighting tower top material in the first heat exchanger, thereby being able to control the heat exchange temperature and heat exchange effect.

[0018] Compared with the prior art, the present invention has the following beneficial effects: the waste heat of the material at 127° C. at the top of the deweighting tower is utilized to preheat the ethylene polymerization reaction product, which can not only significantly reduce the reflux temperature of the material at the top of the tower, but also reduce the steam required for flash distillation and impurity removal of the ethylene polymerization product, thereby reducing energy consumption, reducing the dependence of the reflux of the material at the top of the deweighting tower on the air cooler, and reducing construction and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the heat recovery system for ethylene polymerization treatment.

[0020] Among them, 1. deweighting tower; 2. Reflux tank; 3. Deweighting tower top pipeline; 4. Reaction product pipeline; 5. Refining tower feed pipeline; 6. Refining tower bottom pipeline; 7. First heat exchanger; 8. Second heat exchanger; 9. Third heat exchanger; 10. Air cooler; 11. First switch; 12. Second switch; 13. Third switch; 14. Reflux pipeline. DETAILED DESCRIPTION

[0021] Figure 1 It is the best embodiment of the utility model, and the following Figure 1 The utility model is further described.

[0022] See attached Figure 1 A heat recovery system for ethylene polymerization treatment includes a deweighting tower 1, a reflux tank 2, a deweighting tower top pipeline 3, a reaction product pipeline 4, a refining tower feed pipeline 5, a refining tower bottom pipeline 6, a first heat exchanger 7, a second heat exchanger 8, a third heat exchanger 9, an air cooler 10, a first switch 11, a second switch 12, a third switch 13 and a reflux pipeline 14.

[0023] The top of the deweighting tower 1 is connected to the reflux tank 2 through the deweighting tower top pipeline 3 and the reflux pipeline 14 respectively; the first heat exchanger 7, the second heat exchanger 8 and the third heat exchanger 9 are arranged in parallel on the deweighting tower top pipeline 5, the deweighting tower top pipeline 5 passes through the hot sides of the first heat exchanger 7, the second heat exchanger 8 and the third heat exchanger 9 respectively, and a first switch 11 is provided between the first heat exchanger 7 and the deweighting tower top pipeline 5, a second switch 12 is provided between the second heat exchanger 8 and the deweighting tower top pipeline 5, and a third switch 13 is provided between the third heat exchanger 9 and the deweighting tower top pipeline 5; the reaction product pipeline 4 passes through the cold side of the first heat exchanger 7, and a thermometer is provided between the first switch 11 and the reaction product pipeline 4; the refining tower feed pipeline 5 passes through the cold side of the second heat exchanger 8, and a thermometer is provided between the second switch 12 and the refining tower feed pipeline 5; the refining tower bottom pipeline 6 passes through the cold side of the third heat exchanger 9, and a thermometer is provided between the third switch 13 and the refining tower bottom pipeline 6.

[0024] An air cooler 10 is provided on the reflux pipeline 14 , and a pressure gauge is provided between the reflux pipeline 14 and the top of the deweighting tower 1 , and a thermometer is provided on the air cooler 10 .

[0025] In the process of the top material of the de-weighting tower 1 flowing back to the reflux tank 2 through the top pipeline 3 of the de-weighting tower, the first heat exchanger 7 is used to preheat the ethylene polymerization reaction product in the reaction product pipeline 4, which can just meet the temperature requirements of the subsequent flash evaporation of the reaction product; the second heat exchanger 8 and the third heat exchanger 9 are used to heat the α-olefins fed to the refining tower and the materials at the bottom of the refining tower to meet the subsequent refining process requirements of ethylene polymerization, and the first switch 11, the second switch 12, and the third switch 13 can effectively control the heating pressure of each material pipeline and the heating temperature, which is easy to adjust. At the same time, the top material of the de-weighting tower 1 can also be discharged through the reflux pipeline 14, and the total heat of the external output heat exchange can be effectively controlled through the air cooler 10 on the reflux pipeline 14.

[0026] The above is only the preferred embodiment of the utility model, and does not limit the utility model in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the utility model without departing from the technical solution of the utility model still belongs to the protection scope of the technical solution of the utility model.

Claims

1. An ethylene polymerization heat recovery system, comprising a deweighting tower (1), a reflux tank (2) and a deweighting tower top pipeline (3), wherein the top of the deweighting tower (1) is connected to the reflux tank (2) via the deweighting tower top pipeline (3), characterized in that: It also includes a reaction product pipeline (4) and a first heat exchanger (7), wherein the deweighting tower top pipeline (3) is connected to one side of the first heat exchanger (7), and the reaction product pipeline (4) is connected to the other side of the first heat exchanger (7).

2. The ethylene oligomerization heat recovery system according to claim 1, characterized in that: It also includes a reflux pipeline (14), which connects the top of the deweighting tower (1) and the reflux tank (2).

3. The ethylene oligomerization heat recovery system according to claim 2, characterized in that: It also includes an air cooler (10), which is arranged on the return line (14).

4. The ethylene oligomerization heat recovery system according to claim 3, characterized in that: The air cooler (10) is provided with a thermometer.

5. The ethylene oligomerization heat recovery system according to claim 2 or 3, characterized in that: A pressure gauge is provided between the reflux pipeline (14) and the top of the deweighting tower (1).

6. The ethylene oligomerization heat recovery system according to claim 1, characterized in that: It also includes a refining tower feed pipeline (5) and a second heat exchanger (8), one side of the second heat exchanger (8) is connected in parallel with the first heat exchanger (7) on the deweighting tower top pipeline (3), and the refining tower feed pipeline (5) is connected to the other side of the second heat exchanger (8).

7. The ethylene oligomerization heat recovery system according to claim 6, characterized in that: A second switch (12) is provided between one side of the second heat exchanger (8) and the deweighting tower top pipeline (3).

8. The ethylene oligomerization heat recovery system according to claim 1, characterized in that: It also includes a refining tower bottom pipeline (6) and a third heat exchanger (9), one side of the third heat exchanger (9) is connected in parallel with the first heat exchanger (7) on the deweighting tower top pipeline (3), and the refining tower bottom pipeline (6) is connected to the other side of the third heat exchanger (9).

9. The ethylene oligomerization heat recovery system according to claim 8, characterized in that: A third switch (13) is provided between one side of the third heat exchanger (9) and the deweighting tower top pipeline (3).

10. The ethylene oligomerization heat recovery system according to claim 1, characterized in that: A first switch (11) is provided between the first heat exchanger (7) and the deweighting tower top pipeline (3).

Images