Mobile drying circulation and closed sampling system and operation method

Abstract

The invention discloses a mobile drying circulation and closed sampling system and an operation method, the mobile drying circulation and closed sampling system comprises a first xylene dryer and a second xylene dryer, the first xylene dryer and the second xylene dryer are both filled with 3A molecular sieves and phi 6 porcelain balls, the top of the first xylene dryer is connected with the bottom of the second xylene dryer through a pipeline, and the top of the second xylene dryer is connected with the top of the second xylene dryer through a pipeline. The top of the second xylene dryer is connected with a refined xylene tank through a first pipeline, the bottom of the first xylene dryer is connected with a crude xylene barrel through a second pipeline, the second pipeline is connected with a third pipeline with a stop valve, the third pipeline is used for being connected with a torch, and the bottom of the refined xylene tank is connected with a fifth pipeline. The fifth pipeline is connected with the second pipeline, the fourth pipeline is used for being connected with nitrogen and connected with a starting diaphragm pump, and the fifth pipeline is connected with a closed sampling pipeline with a stop valve. The device has the technical advantages that various solvents can be dried anytime and anywhere, and it is guaranteed that sampling is not affected by the content of water in air.

Description

Technical Field

[0001] The present invention relates to a system and an operating method, and more specifically, to a mobile drying cycle and closed sampling system and an operating method, and belongs to the field of petrochemical industry. Background Art

[0002] At present, the trimerization and tetramerization products of the 1,000 tons / year alpha olefin unit in the olefin separation department of the super-large-scale petrochemical industry, such as 1-hexene and 1-octene, are important raw materials for the production of high-performance polyethylene. The polyethylene copolymers obtained with 1-octene as a comonomer have significantly improved tear strength and impact strength. At present, there is no dedicated 1-octene production facility in China, and the expensive 1-octene is mainly imported from abroad to meet market demand. Therefore, the development of 1-octene production technology has a positive effect on improving the brand of polyethylene products and solving the industry characteristics of serious homogeneity of domestic ethylene downstream products and heavy reliance on imports of high-end products.

[0003] Water content is a key indicator that affects the start-up and production of alpha olefin units. In production, solvents, additives, and terminators must all strictly control water content to ≤5ppm, but it is difficult for pilot plants to achieve ≤5ppm, and many factors need to be overcome. The water content of solvents and additives such as xylene, toluene, and terminator isooctyl alcohol used in the unit design can reach more than 100ppm before entering the system, causing water to react with triethylaluminum in the pipeline to generate aluminum hydroxide, clogging the system, and causing the water content of the product to exceed the standard. Therefore, it is an inevitable trend in research and development to design a mobile drying circulation system and a closed sampling system that is easy to move and does not require the replacement or regeneration of the molecular sieve every time the drying medium is replaced, so as to ensure that drying and dehydration are completed with a small amount of solvent. Summary of the invention

[0004] In order to solve the above-mentioned problems of the prior art, the present invention provides a mobile drying cycle and closed sampling system and operation method having the technical characteristics of being able to dry various solvents anytime and anywhere and ensuring that sampling is not affected by the water content in the air.

[0005] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0006] The present invention discloses a mobile drying circulation and closed sampling system, comprising a frame with movable wheels, wherein a No. 1 xylene dryer and a No. 2 xylene dryer are arranged on the frame, wherein the No. 1 xylene dryer and the No. 2 xylene dryer are both filled with 3A molecular sieve and φ6 porcelain balls, wherein the top of the No. 1 xylene dryer is connected to the bottom of the No. 2 xylene dryer through a pipeline with a stop valve, and the top of the No. 2 xylene dryer is connected to a refined xylene tank through a No. 1 pipeline with a stop valve. The bottom of the No. 1 xylene dryer is connected to a crude xylene barrel through the No. 2 pipeline, the No. 3 pipeline with a stop valve is connected to the No. 2 pipeline, and the No. 3 pipeline is used to access the torch. The bottom of the refined xylene tank is connected to the No. 5 pipeline, and the No. 5 pipeline is connected to the No. 2 pipeline. The No. 4 pipeline is connected to the No. 2 pipeline between the No. 5 pipeline and the No. 3 pipeline, and the No. 4 pipeline is used to access nitrogen and is connected to a starting diaphragm pump, and the No. 5 pipeline is connected to a closed sampling pipeline with a stop valve.

[0007] Preferably, the closed sampling pipeline includes a nitrogen pipeline and a xylene pipeline, the nitrogen pipeline is connected with valve V-1, valve V-7, and valve V-8, one end of the xylene pipeline is connected to pipeline No. 5 8, and the other end is a vent, the xylene pipeline 12 is connected with valve V-3, a one-way valve, and valve V-9, the xylene pipeline at the outlet section of the valve V-3 is connected with an external pipeline with valve V-4, the nitrogen pipeline between the valve V-1 and the valve V-7 is connected with pipeline No. 6 with valve V-2, the pipeline No. 6 is connected to the xylene pipeline between valve V-3 and the one-way valve, and the end of the nitrogen pipeline 11 is connected to the xylene pipeline between the one-way valve and valve V-9;

[0008] The xylene pipeline between the one-way valve and pipeline No. 6 is a detachable pipeline, which is formed by connecting line A and line B. Line A can be connected to pipeline No. 7 with a stop valve, and line B can be connected to pipeline No. 8 with a stop valve. Pipeline No. 7 is extended into the sampling bottle, and pipeline No. 8 is connected to the upper end of the sampling bottle.

[0009] The present invention provides an operating method of a mobile drying cycle and closed sampling system, comprising the following sampling steps:

[0010] Step 1: Replace pipeline: connect line A and line B, open valve v-1, valve v-2, valve V-4, valve v-9, close other valves in the closed sampling pipeline, introduce nitrogen and purge the pipeline through line A 13 and line B 14 to vent for 5 minutes;

[0011] Step 2: Open valve v-7 and valve v-8, close valve v-2 to reduce the exhaust volume of valve v-4, and disconnect line A and line B;

[0012] Step 3: Connect the sampling bottle: connect line A to the No. 7 pipeline with a stop valve, connect line B to the No. 8 pipeline with a stop valve, extend the No. 7 pipeline into the sampling bottle, and connect the No. 8 pipeline to the upper end of the sampling bottle;

[0013] Step 4: Close valves v-4, v-7, and v-8, open valves V-2, V-5, and V-6, and replace the sampling bottle with nitrogen for 10 minutes;

[0014] Step 5: Close valve V-2 and turn down valve v-8 to reduce the exhaust volume at the vent;

[0015] Step 6: Gradually open valve v-3 to start sampling. When the sampling bottle has sampled 70%, close valve v-3, valve V-5, and valve V-6;

[0016] Step 7: Open valve v-2 and valve V-4, and blow down the inlet pipeline with nitrogen;

[0017] Step 8: Close valve v-1, valve v-2, valve v-9, valve V-4, valve v-7, valve v-8, remove the sampling bottle, and restore the connection between line A and line B.

[0018] Beneficial effects: The samples are taken and analyzed in a closed manner during the cycle drying process. After the analysis is qualified, the samples enter the refined container buffer tank. The substances that can be dried include xylene, toluene, isooctyl alcohol, etc. The molecular sieve of the dryer needs to be replaced and regenerated each time the medium is replaced. This cycle dryer is mobile and can dry various solvents anytime and anywhere. A special closed sampling system is set up to ensure that the sampling is not affected by the water content in the air. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a diagram of the mobile drying cycle system of the present invention.

[0020] Figure 2 It is a closed sampling diagram of the present invention.

[0021] Figure 3 It is a diagram of the closed sampling system of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

[0023] like Figure 1-3 The figure shows a specific embodiment of a mobile drying cycle and closed sampling system. The embodiment is a mobile drying cycle and closed sampling system, comprising a frame with mobile wheels, on which a No. 1 xylene dryer 1 and a No. 2 xylene dryer 2 are arranged. The No. 1 xylene dryer 1 and the No. 2 xylene dryer 2 are filled with 3A molecular sieve and Porcelain ball, the top of the No. 1 xylene dryer 1 is connected to the bottom of the No. 2 xylene dryer 2 through a pipeline with a stop valve, the top of the No. 2 xylene dryer 2 is connected to the refined xylene tank 4 through the No. 1 pipeline 3 with a stop valve, the bottom of the No. 1 xylene dryer 1 is connected to a crude xylene barrel 6 through the No. 2 pipeline 5, the No. 2 pipeline 5 is connected to the No. 3 pipeline 7 with a stop valve, the No. 3 pipeline 7 is used to access the torch, the bottom of the refined xylene tank 4 is connected to the No. 5 pipeline 8, the No. 5 pipeline 8 is connected to the No. 2 pipeline 5, the No. 4 pipeline 9 is connected to the No. 2 pipeline 5 between the No. 5 pipeline 8 and the No. 3 pipeline 7, the No. 4 pipeline 9 is used to access nitrogen and is connected to a starting diaphragm pump, and the No. 5 pipeline 8 is connected to a closed sampling pipeline 10 with a stop valve.

[0024] The mobile circulating drying system in this application preferably uses two xylene dryers filled with 3A molecular sieve and The ceramic ball is then connected to temporary hot nitrogen from the device, and the temperature is raised to 200°C to regenerate the molecular sieve. After the regeneration is completed, the crude solvent additives and the like are sent to two xylene dryers (No. 1 xylene dryer 1 and No. 2 xylene dryer 2) through a pneumatic diaphragm pump for circulation drying. During the circulation drying process, a closed sampling pipeline 10 is used for closed sampling and analysis. After the analysis is qualified, it enters the refining container buffer tank. The substances dried in the technical scheme of the present application may include xylene, toluene, isooctyl alcohol, etc. Each time the medium is dried and replaced, the molecular sieve of the dryer needs to be replaced and regenerated. This circulation dryer is mobile and can dry various solvents anytime and anywhere. In the technical scheme of the present application, the mobile circulation drying is combined with the closed sampling pipeline 10, and its special closed sampling system ensures that the sampling is not affected by the water content in the air.

[0025] During the start-up of the trimerization of the α-olefin unit, the water content of the solvent or terminator did not meet the requirement of ≤5ppm, causing the water content of the product 1-hexene to exceed the standard and the product was unqualified. After passing through the mobile circulating drying system, the water content of xylene has reached the specified requirement.

[0026] Actual production data using the technical solution of this application:

[0027]

[0028] The water content of 1-hexene product exceeds the standard

[0029]

[0030]

[0031] The water content of xylene dropped to 3.9 ppm after passing through the circulating drying system.

[0032] In a preferred embodiment, the closed sampling pipeline 10 includes a nitrogen pipeline 11 and a xylene pipeline 12. The nitrogen pipeline 11 is connected to valves V-1, V-7 and V-8. One end of the xylene pipeline 12 is connected to the No. 5 pipeline 8, and the other end is a vent. The xylene pipeline 12 is connected to valves V-3, a one-way valve and valve V-9. The xylene pipeline 12 is connected to an external pipeline with valve V-4 at the outlet section of valve V-3. The nitrogen pipeline 11 between valves V-1 and V-7 is connected to a valve V- 2, the No. 6 pipeline is connected to the valve V-3 and the xylene pipeline 12 between the one-way valve, and the end of the nitrogen pipeline 11 is connected to the xylene pipeline 12 between the one-way valve and the valve V-9; the xylene pipeline 12 between the one-way valve and the No. 6 pipeline is a detachable pipeline, and the detachable pipeline is formed by connecting the A line 13 and the B line 14, the A line 13 can be connected to the No. 7 pipeline with a stop valve, the B line 14 can be connected to the No. 8 pipeline with a stop valve, the No. 7 pipeline is extended into the sampling bottle, and the No. 8 pipeline is connected to the upper end of the sampling bottle.

[0033] The present invention provides an operating method of a mobile drying cycle and closed sampling system, comprising the following sampling steps:

[0034] Step 1: Replace pipeline: connect line A 13 and line B 14, open valve v-1, valve v-2, valve V-4, valve v-9, close other valves in the closed sampling pipeline 10, introduce nitrogen and purge the pipeline through line A 13 and line B 14 to vent for 5 minutes;

[0035] Step 2: Open valve v-7 and valve v-8, close valve v-2 to reduce the exhaust volume of valve v-4, and disconnect line A 13 and line B 14;

[0036] Step 3: Connect the sampling bottle: connect the A line 13 to the No. 7 pipeline with a stop valve, connect the B line 14 to the No. 8 pipeline with a stop valve, extend the No. 7 pipeline into the sampling bottle, and connect the No. 8 pipeline to the upper end of the sampling bottle;

[0037] Step 4: Close valves v-4, v-7, and v-8, open valves V-2, V-5, and V-6, and replace the sampling bottle with nitrogen for 10 minutes;

[0038] Step 5: Close valve V-2 and turn down valve v-8 to reduce the exhaust volume at the vent;

[0039] Step 6: Gradually open valve v-3 to start sampling. When the sampling bottle has sampled 70%, close valve v-3, valve V-5, and valve V-6;

[0040] Step 7: Open valve v-2 and valve V-4, and blow down the inlet pipeline with nitrogen;

[0041] Step 8: Close valve v-1, valve v-2, valve v-9, valve V-4, valve v-7, valve v-8, remove the sampling bottle, and restore the connection between line A 13 and line B 14.

[0042] The pilot plant is an essential test device for large chemical plants. It is a device that provides technical support and various test data for large devices. Some pilot plants cannot control the water content of solvents or additives, and a special drying system is expensive and costly. The mobile circulating drying system designed and manufactured for use in this application fundamentally solves this problem and has been applied in practice with good results, with a total cost of 20,000 yuan.

[0043] Finally, it should be noted that the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by ordinary technicians in this field should be considered as the protection scope of the present invention.

Claims

1. A mobile drying cycle and closed sampling system, characterized in that: The invention comprises a frame with movable wheels, wherein a No. 1 xylene dryer (1) and a No. 2 xylene dryer (2) are arranged on the frame, wherein the No. 1 xylene dryer (1) and the No. 2 xylene dryer (2) are both filled with 3A molecular sieve and φ6 porcelain balls, wherein the top of the No. 1 xylene dryer (1) is connected to the bottom of the No. 2 xylene dryer (2) via a pipeline with a stop valve, wherein the top of the No. 2 xylene dryer (2) is connected to a refined xylene tank (4) via a No. 1 pipeline (3) with a stop valve, and the bottom of the No. 1 xylene dryer (1) is connected to a No. 2 pipeline (5). A crude xylene barrel (6) is connected to the No. 2 pipeline (5), and a No. 3 pipeline (7) with a stop valve is connected to the No. 2 pipeline (5), and the No. 3 pipeline (7) is used to access the flare. The bottom of the refined xylene tank (4) is connected to the No. 5 pipeline (8), and the No. 5 pipeline (8) is connected to the No. 2 pipeline (5). The No. 2 pipeline (5) between the No. 5 pipeline (8) and the No. 3 pipeline (7) is connected to the No. 4 pipeline (9), and the No. 4 pipeline (9) is used to access nitrogen and is connected to a starting diaphragm pump. The No. 5 pipeline (8) is connected to a closed sampling pipeline (10) with a stop valve.

2. A mobile drying cycle and closed sampling system according to claim 1, characterized in that: The sealed sampling pipeline (10) comprises a nitrogen pipeline (11) and a xylene pipeline (12). The nitrogen pipeline (11) is connected with valves V-1, V-7 and V-8. One end of the xylene pipeline (12) is connected with pipeline No. 5 (8), and the other end is a vent. The xylene pipeline (12) is connected with valves V-3, a one-way valve and valve V-9. The xylene pipeline (12) at the outlet section of valve V-3 is connected with an external pipeline with valve V-4. The nitrogen pipeline (11) between valves V-1 and V-7 is connected with pipeline No. 6 with valve V-2. The pipeline No. 6 is connected to the xylene pipeline (12) between valves V-3 and the one-way valve. The end of the nitrogen pipeline (11) is connected to the xylene pipeline (12) between the one-way valve and valve V-9. The xylene pipeline (12) between the one-way valve and the No. 6 pipeline is a detachable pipeline, which is formed by connecting the A line (13) and the B line (14). The A line (13) can be connected to the No. 7 pipeline with a stop valve, and the B line (14) can be connected to the No. 8 pipeline with a stop valve. The No. 7 pipeline is extended into the sampling bottle, and the No. 8 pipeline is connected to the upper end of the sampling bottle.

3. A method for operating a mobile drying cycle and closed sampling system according to any one of claims 1 to 2, characterized in that The sampling steps include the following: Step 1): Replace the pipeline: connect line A (13) and line B (14), open valve v-1, valve v-2, valve V-4, valve v-9, close other valves in the closed sampling pipeline (10), introduce nitrogen and purge the pipeline through line A (13) and line B (14) for 5 minutes; Step 2): Open valve v-7 and valve v-8, close valve v-2 to reduce the exhaust volume of valve v-4, and disconnect line A (13) and line B (14); Step 3): Connecting the sampling bottle: connecting line A (13) to pipeline No. 7 with a stop valve, connecting line B (14) to pipeline No. 8 with a stop valve, extending pipeline No. 7 into the sampling bottle, and connecting pipeline No. 8 to the upper end of the sampling bottle; Step 4): Close valves v-4, v-7, and v-8, open valves V-2, V-5, and V-6, and replace the sampling bottle with nitrogen for 10 minutes; Step 5): Close valve V-2 and turn down valve v-8 to reduce the exhaust volume of the vent; Step 6): gradually open valve v-3 to start sampling. When the sampling bottle has sampled 70%, close valve v-3, valve V-5, and valve V-6; Step 7): Open valve v-2 and valve V-4, and blow down the inlet pipeline with nitrogen; Step 8): Close valve v-1, valve v-2, valve v-9, valve V-4, valve v-7, valve v-8, remove the sampling bottle, and restore the connection between line A (13) and line B (14).

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