C4 dehydration device

Abstract

The utility model belongs to the fields of petrochemical industry and the like, and discloses a C4 dehydration device. The C4 dehydration device comprises an adsorption dehydration system and a regeneration system, the regeneration system comprises a regenerated gas feeding structure, a regenerated gas heating structure, a recycled gas cooling structure and a recycled gas liquid separation tank, the regenerated gas feeding structure is connected with the regenerated gas heating structure, the regenerated gas heating structure is connected with regenerated gas feeding pipelines of all adsorption dehydrators, and the recycled gas liquid separation tank is connected with the regenerated gas feeding pipelines of all the adsorption dehydrators. A regenerated gas discharging pipeline of each adsorption dehydrator is connected with a recycled gas cooling structure, the recycled gas cooling structure is connected with a recycled gas liquid separation tank, a liquid outlet is formed in the bottom of the recycled gas liquid separation tank, a recycled gas outlet is formed in the upper part of the recycled gas liquid separation tank, and the recycled gas outlet of the recycled gas liquid separation tank is connected with a regenerated gas feeding structure. According to the mixed C4 dehydration device, when regeneration gas is used for regenerating the molecular sieve, the regeneration gas is cooled and subjected to liquid separation, so that the regeneration gas is recycled, and the consumption of the regeneration gas can be greatly reduced.

Description

Technical Field

[0001] The utility model relates to a carbon four dehydration device, belonging to the fields of petrochemical industry and the like. Background Art

[0002] In the field of petrochemicals, C4 refers to hydrocarbons containing 10 carbon atoms such as n-butane, isobutane, n-butene, isobutene, cis-butene, and trans-butene. Mixed C4 is a mixture of the above C4 hydrocarbons, and mixed C4 usually contains free water. When mixed C4 is used as a raw material to produce alkylated gasoline by sulfuric acid alkylation, the amount of water in the mixed C4 raw material directly affects the consumption of sulfuric acid. The more water, the higher the sulfuric acid consumption. At present, the dehydration of mixed C4 in China mainly adopts fiber agglomeration dehydration, ultra-gravity hydrocyclone dehydration, etc., and the effect is not ideal. The water content of the mixed C4 after dehydration treatment generally exceeds 500PPM.

[0003] The Chinese patent application with publication number CN209475592U discloses a system for dehydrating raw carbon four in alkylation production, wherein two dehydration towers arranged in parallel perform dehydration in turn, the molecular sieves are filled in the dehydration towers to absorb the water in the raw carbon four, and then the molecular sieves are regenerated by heated nitrogen, and the two dehydration towers are switched regularly, one for absorption and the other for regeneration. The dehydration effect of carbon four can be greatly improved by molecular sieve absorption, and the water content in the raw carbon four can be reduced to below 10ppm. The molecular sieves are regenerated by using hot nitrogen as regeneration gas, and continuous production can be achieved.

[0004] However, the above-mentioned carbon four dehydration system still has certain problems, mainly in that new hot nitrogen needs to be continuously injected during the regeneration process using hot nitrogen, which not only consumes a lot of nitrogen. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a carbon four dehydration device to effectively reduce the consumption of molecular sieve regeneration gas.

[0006] The C4 dehydration device disclosed in the utility model comprises an adsorption dehydration system and a regeneration system;

[0007] The adsorption dehydration system comprises at least two adsorption dehydrators, wherein a molecular sieve for absorbing water molecules is arranged in the adsorption dehydrator, and a carbon four feed pipeline, a carbon four discharge pipeline, a regeneration gas feed pipeline and a regeneration gas discharge pipeline are respectively connected at both ends of each adsorption dehydrator, and the carbon four feed pipeline, the carbon four discharge pipeline, the regeneration gas feed pipeline and the regeneration gas discharge pipeline are all provided with valves;

[0008] The regeneration system includes a regeneration gas feeding structure, a regeneration gas heating structure, a recovery gas cooling structure and a recovery gas liquid separator tank. The regeneration gas feeding structure is connected to the regeneration gas heating structure. The regeneration gas heating structure is respectively connected to the regeneration gas feed pipeline of each adsorption dehydrator. The regeneration gas discharge pipeline of each adsorption dehydrator is connected to the recovery gas cooling structure. The recovery gas cooling structure is connected to the recovery gas liquid separator tank. A liquid outlet is provided at the bottom of the recovery gas liquid separator tank. A recovery gas outlet is provided at the top of the recovery gas liquid separator tank. The recovery gas outlet of the recovery gas liquid separator tank is connected to the regeneration gas feeding structure.

[0009] Preferably, the regeneration system includes a heat exchanger, which includes a hot fluid part and a cold fluid part. The cold fluid part of the heat exchanger is connected between the regeneration gas feed structure and the regeneration gas heating structure as the regeneration gas heating structure, and the hot fluid part of the heat exchanger is connected between the recovery gas liquid separator tank and the recovery gas liquid separator tank as the recovery gas cooling structure.

[0010] Preferably, the recovered gas cooling structure further includes a cooler, and the cooler is connected between the recovered gas liquid separation tank and the heat exchanger.

[0011] Preferably, the regeneration gas heating structure further includes a heater, and the heater is connected between the adsorption dehydrator and the heat exchanger.

[0012] Preferably, a connecting pipe is connected between the inlet end and the outlet end of the heater, and valves are arranged on the inlet end, the outlet end and the connecting pipe of the heater.

[0013] Preferably, the regeneration gas feed structure comprises an external gas feed pipe and a blower, the external gas feed pipe and the recovery gas outlet of the recovery gas separator are both connected to the air inlet of the blower, and the air outlet of the blower is connected to the regeneration gas heating structure.

[0014] Preferably, the adsorption dehydrator is connected to a waste regeneration gas discharge pipeline, and the waste regeneration gas discharge pipeline is located at the same end of the regeneration gas discharge pipeline of the adsorption dehydrator and is correspondingly provided with a valve.

[0015] The beneficial effect of the utility model is that when the mixed C4 dehydration device of the present application utilizes the regeneration gas to regenerate the molecular sieve, the regeneration gas is cooled and separated to achieve the recovery of the regeneration gas, which can greatly reduce the consumption of the regeneration gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the carbon four dehydration device of the present application.

[0017] Figure numerals: adsorption dehydrator 1, C4 feed pipeline 11, C4 discharge pipeline 12, regeneration gas feed pipeline 13, regeneration gas discharge pipeline 14, waste regeneration gas discharge pipeline 15, heater 2, heat exchanger 3, cooler 4, recovery gas separator 5, liquid outlet 51, recovery gas outlet 52, blower 6, external gas feed pipe 7. DETAILED DESCRIPTION

[0018] The utility model is further described below.

[0019] The C4 dehydration device disclosed in the utility model comprises an adsorption dehydration system and a regeneration system;

[0020] The adsorption dehydration system comprises at least two adsorption dehydrators 1, wherein a molecular sieve for absorbing water molecules is arranged in the adsorption dehydrator 1, and both ends of each adsorption dehydrator 1 are respectively connected with a mixed C4 feed pipeline 11, a mixed C4 discharge pipeline 12, a regeneration gas feed pipeline 13 and a regeneration gas discharge pipeline 14, and the mixed C4 feed pipeline 11, the mixed C4 discharge pipeline 12, the regeneration gas feed pipeline 13 and the regeneration gas discharge pipeline 14 are all provided with valves;

[0021] The regeneration system includes a regeneration gas feeding structure, a regeneration gas heating structure, a recovery gas cooling structure and a recovery gas liquid separator tank 5, the regeneration gas feeding structure is connected to the regeneration gas heating structure, the regeneration gas heating structure is respectively connected to the regeneration gas feeding pipeline 13 of each adsorption dehydrator 1, the regeneration gas discharge pipeline 14 of each adsorption dehydrator 1 is connected to the recovery gas cooling structure, the recovery gas cooling structure is connected to the recovery gas liquid separator tank 5, the recovery gas liquid separator tank 5 is provided with a liquid outlet 51 at the bottom, the recovery gas liquid separator tank 5 is provided with a recovery gas outlet 52 at the top, and the recovery gas outlet 52 of the recovery gas liquid separator tank 5 is connected to the regeneration gas feeding structure.

[0022] The mixed C4 dehydration method using the mixed C4 dehydration device is as follows:

[0023] Open the valves of the mixed C4 feed pipeline 11 and the mixed C4 discharge pipeline 12 of at least one adsorption dehydrator 1, and pass the water-containing mixed C4 into the adsorption dehydrator 1 through the mixed C4 feed pipeline 11, and the mixed C4 after water removal is discharged from the mixed C4 discharge pipeline 12;

[0024] When the water content of the mixed C4 outputted from the mixed C4 discharge pipeline 12 of the adsorption dehydrator 1 approaches or reaches the set value, the valves of the mixed C4 feed pipeline 11 and the mixed C4 discharge pipeline 12 of the standby adsorption dehydrator 1 are opened to dehydrate the mixed C4 through the standby adsorption dehydrator 1;

[0025] Close the valves of the mixed C4 feed pipeline 11 and the mixed C4 discharge pipeline 12 of the adsorption dehydrator 1 after water absorption, open the valves of the regeneration gas feed pipeline 13 and the regeneration gas discharge pipeline 14 of the adsorption dehydrator 1 after water absorption, and introduce the regeneration gas through the regeneration gas feed structure. After the regeneration gas is heated by the regeneration gas heating structure, it enters the adsorption dehydrator 1 after water absorption through the regeneration gas feed pipeline 13 to regenerate the molecular sieve in the adsorption dehydrator 1, and the recovered gas containing water vapor is output from the regeneration gas discharge pipeline 14 of the adsorption dehydrator 1 after water absorption, enters the recovered gas cooling structure, cools the water vapor in the recovered gas into liquid water, separates the liquid water through the recovered gas separator 5, and the recovered gas after the liquid water is separated enters the regeneration gas feed structure for recycling again, and the accumulated liquid water can be discharged from the liquid outlet 51 at the bottom of the recovered gas separator. When the pressure of the entire regeneration gas circulation system is balanced, stop introducing new regeneration gas, and allow the regeneration gas to circulate in the regeneration system;

[0026] After the regeneration gas circulates for a period of time, the water content of the gas in the regeneration gas outlet pipe of the dehydrator is analyzed and tested. If it is qualified, the corresponding regeneration gas feed pipeline 13 and regeneration gas outlet pipeline 14 valves are closed and wait for the next cycle. To ensure safety, all valves in the regeneration system can be closed, and the regenerated dehydrator waits for the next adsorption. During the waiting process, the adsorbent bed will naturally cool down to room temperature. Nitrogen is usually used for regeneration gas. Nitrogen is inert to olefins in mixed carbon four and does not cause olefin polymerization. Other gases such as inert gas that are inert to olefins in mixed carbon four can also be used, but the cost of using nitrogen is the lowest.

[0027] The regeneration gas heating structure and the recovery gas cooling structure can respectively adopt independent heating structures and cooling structures, but in the preferred embodiment of the present application, the regeneration system includes a heat exchanger 3, and the heat exchanger 3 includes a hot fluid part and a cold fluid part. The cold fluid part of the heat exchanger 3 is connected between the regeneration gas feed structure and the regeneration gas heating structure as the regeneration gas heating structure, and the hot fluid part of the heat exchanger 3 is connected between the recovery gas liquid separator 5 and the recovery gas liquid separator 5 as the recovery gas cooling structure. The heat exchanger 3 serves as both the regeneration gas heating structure and the recovery gas cooling structure, which can make full use of thermal energy and reduce energy consumption.

[0028] Although the heat exchanger 3 can achieve heating of the regenerated gas and cooling of the recovered gas, its heating and cooling degrees are usually difficult to meet the standards. Therefore, in the preferred embodiment of the present application, the recovered gas cooling structure also includes a cooler 4, which is connected between the recovered gas liquid separator 5 and the heat exchanger 3, and the recovered gas is further cooled by the other cooler 4. In addition, the regenerated gas heating structure also includes a heater 2, which is connected between the adsorption dehydrator 1 and the heat exchanger 3. The recovered gas is further heated by the other heater 2, so that the heating of the regenerated gas and the cooling of the recovered gas can meet the requirements.

[0029] After the regeneration gas circulates for a certain period of time, the regeneration gas heated by the heat exchanger 3 can reach the temperature requirement. At this time, it is no longer necessary to heat it. Therefore, in the preferred embodiment of the present application, a connecting pipe is connected between the inlet and outlet ends of the heater 2, and valves are provided on the inlet and outlet ends of the heater 2 and the connecting pipe. When the temperature of the regeneration gas heated by the heat exchanger 3 is insufficient and further heating by the heater 2 is required, the valve on the connecting pipe is closed, the valves at the inlet and outlet ends of the heater 2 are opened, and the regeneration gas enters the heater 2 for further heating. When the temperature of the regeneration gas heated by the heat exchanger 3 is sufficient, the valve on the connecting pipe is opened, the valves at the inlet and outlet ends of the heater 2 are closed, and the regeneration gas directly enters the adsorption dehydrator 1 by bypassing the heater 2.

[0030] The regeneration gas feeding structure is used to introduce external regeneration gas and circulating recovery gas. In order to facilitate the transportation of gas, the regeneration gas feeding structure includes an external gas feeding pipe 7 and a blower 6. The external gas feeding pipe 7 and the recovery gas outlet 52 of the recovery gas separator 5 are both connected to the air inlet of the blower 6, and the air outlet of the blower 6 is connected to the regeneration gas heating structure. The blower 6 can provide power for the circulation system and speed up the input of the external gas to be transported. In addition to this embodiment, the position of the blower 6 can also be set separately on the regeneration system, but it is difficult to play the maximum role.

[0031] Before the adsorption dehydrator 1 is regenerated, it contains a large amount of carbon four, which will bring certain dangers if it enters the regeneration system. Therefore, in the preferred embodiment of the present application, the adsorption dehydrator 1 is connected to a waste regeneration gas discharge pipeline 15, and the waste regeneration gas discharge pipeline 15 is located at the same end of the regeneration gas discharge pipeline 14 of the adsorption dehydrator 1 and a valve is correspondingly provided. When the adsorption dehydrator 1 is fed with regeneration gas, the waste regeneration gas discharge pipeline 15 is opened first, and the regeneration gas containing hydrocarbons is discharged first, and then the regeneration gas is recycled, and the discharged regeneration gas containing hydrocarbons can enter the recovery system to recover hydrocarbons.

[0032] The following is an example of the actual use of the carbon four dehydration device of the present application.

[0033] Example 1

[0034] Dehydration equipment: 200,000 tons / year alkylation unit supporting mixed C4 dehydration unit;

[0035] Designed to process raw materials: ether-mixed C4;

[0036] Designed ether treatment and mixing capacity: 225,000 tons / year;

[0037] Water content in the mixed C4 raw material after etherification: 0.05-0.5% (mass);

[0038] Device operation time: 8000 hours / year;

[0039] The water content in the post-ether C4 after dehydration (i.e. the material entering the alkylation reactor) is: <50 PPM (mass).

[0040] Example 2

[0041] Dehydration equipment: 160,000 tons / year alkylation unit supporting mixed C4 dehydration unit;

[0042] Designed to process raw materials: ether mixed with C4;

[0043] Designed ether treatment and mixing capacity: 180,000 tons / year;

[0044] Water content in the mixed C4 raw material after etherification: 0.05-0.5% (mass);

[0045] Device operation time: 8000 hours / year;

[0046] The water content in the post-ether C4 after dehydration (i.e. the material entering the alkylation reactor) is: <50 PPM (mass).

[0047] Example 3

[0048] Dehydration equipment: 240,000 tons / year alkylation unit supporting mixed C4 dehydration unit;

[0049] Designed to process raw materials: ether mixed with C4;

[0050] Designed ether treatment and mixing capacity: 270,000 tons / year;

[0051] Water content in the mixed C4 raw material after etherification: 0.05-0.5% (mass);

[0052] Device operation time: 8000 hours / year;

[0053] The water content in the post-ether C4 after dehydration (i.e. the material entering the alkylation reactor) is: <50 PPM (mass).

Claims

1. C4 dehydration device, including adsorption dehydration system and regeneration system; The adsorption dehydration system comprises at least two adsorption dehydrators (1), wherein a molecular sieve for absorbing water molecules is arranged in the adsorption dehydrator (1), and two ends of each adsorption dehydrator (1) are respectively connected to a carbon four feed pipeline (11), a carbon four discharge pipeline (12), a regeneration gas feed pipeline (13) and a regeneration gas discharge pipeline (14), and the carbon four feed pipeline (11), the carbon four discharge pipeline (12), the regeneration gas feed pipeline (13) and the regeneration gas discharge pipeline (14) are all provided with valves; It is characterized in that The regeneration system comprises a regeneration gas feeding structure, a regeneration gas heating structure, a recovery gas cooling structure and a recovery gas liquid separator tank (5), wherein the regeneration gas feeding structure is connected to the regeneration gas heating structure, the regeneration gas heating structure is respectively connected to the regeneration gas feeding pipeline (13) of each adsorption dehydrator (1), the regeneration gas discharge pipeline (14) of each adsorption dehydrator (1) is connected to the recovery gas cooling structure, the recovery gas cooling structure is connected to the recovery gas liquid separator tank (5), the recovery gas liquid separator tank (5) is provided with a liquid outlet (51) at the bottom, the recovery gas liquid separator tank (5) is provided with a recovery gas outlet (52) at the top, and the recovery gas outlet (52) of the recovery gas liquid separator tank (5) is connected to the regeneration gas feeding structure.

2. The C4 dehydration device according to claim 1, It is characterized in that The regeneration system comprises a heat exchanger (3), wherein the heat exchanger (3) comprises a hot fluid portion and a cold fluid portion, wherein the cold fluid portion of the heat exchanger (3) is connected between a regeneration gas feed structure and a regeneration gas heating structure to serve as the regeneration gas heating structure, and the hot fluid portion of the heat exchanger (3) is connected between a recovery gas liquid separator tank (5) and a recovery gas liquid separator tank (5) to serve as the recovery gas cooling structure.

3. The C4 dehydration device as claimed in claim 2, It is characterized in that The recovered gas cooling structure further comprises a cooler (4), wherein the cooler (4) is connected between the recovered gas liquid separation tank (5) and the heat exchanger (3).

4. The C4 dehydration device according to claim 2, It is characterized in that The regeneration gas heating structure also includes a heater (2), and the heater (2) is connected between the adsorption dehydrator (1) and the heat exchanger (3).

5. The C4 dehydration device according to claim 4, It is characterized in that A connecting pipe is connected between the inlet and outlet ends of the heater (2), and valves are provided on the inlet and outlet ends of the heater (2) and the connecting pipe.

6. The C4 dehydration device according to claim 1, Features: The regeneration gas feeding structure comprises an external gas feeding pipe (7) and a blower (6); the external gas feeding pipe (7) and the recovery gas outlet (52) of the recovery gas separator (5) are both connected to the air inlet of the blower (6); and the air outlet of the blower (6) is connected to the regeneration gas heating structure.

7. The C4 dehydration device according to claim 1, It is characterized in that The adsorption dehydrator (1) is connected to a waste regeneration gas discharge pipeline (15), and the waste regeneration gas discharge pipeline (15) is located at the same end as the regeneration gas discharge pipeline (14) of the adsorption dehydrator (1) and is provided with a corresponding valve.

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