Ethylbenzene recovery treatment system of POSM device

Abstract

The invention relates to the technical field of ethylbenzene recovery treatment, and particularly discloses a POSM device ethylbenzene recovery treatment system which comprises a ground tank, an ethylbenzene waste liquid discharge tank is arranged in the ground tank, a ground tank cover plate is arranged at the top of the ground tank, and a vacuum system is connected to the ground tank. The top of the ethylbenzene waste liquid discharging tank is connected with an ethylbenzene collecting pipeline, a first nitrogen conveying pipeline, a second nitrogen conveying pipeline, a pressure detection and split-ranging control device, a liquid level display device, a gas phase feeding line and a liquid phase feeding line; the waste liquid containing the ethylbenzene material in the POSM device can be shunted and collected in the storage tank, a gas-phase pipeline in the storage tank is conveyed to a VOC treatment system or a torch or an HPW system to ensure that the waste liquid is not discharged into air, and a liquid-phase substance in the storage tank is conveyed to an unqualified ethylbenzene tank through a pump to be recycled, so that the loss of ethylbenzene is reduced, and the waste liquid containing the ethylbenzene material in the POSM device is recycled. Meanwhile, the harm of ethylbenzene to operators in the production process is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ethylbenzene recovery and treatment, and specifically to an ethylbenzene recovery and treatment system for a POSM device. Background Art

[0002] Styrene (SM) is an important chemical raw material. Its most important use is as a monomer for synthetic rubber and plastics, used to produce styrene-butadiene rubber, polystyrene, and expanded polystyrene; it is also used in copolymerization with other monomers to manufacture various engineering plastics with different uses. The production methods of styrene worldwide mainly include: ethylbenzene dehydrogenation to produce styrene, ethylbenzene co-oxidation method, selective oxidation dehydrogenation process and other production technologies. Among them, ethylbenzene dehydrogenation is the main method for producing styrene at home and abroad, and about 90% of the world's styrene is produced by this method. The ethylbenzene co-oxidation method combines the endothermic reaction of ethylbenzene dehydrogenation and the exothermic reaction of propylene oxidation, so that this process does not require too high a reaction temperature. It can save energy and reduce the pollution generated during the production of propylene oxide. Combining the endothermic reaction of ethylbenzene dehydrogenation and the exothermic reaction of propylene oxidation makes this process not require too high a reaction temperature. It can save energy and reduce the pollution generated during the production of propylene oxide. The disadvantages are long process, many by-products, and low styrene yield. In view of the characteristics of many by-products in the POSM co-production device and the toxicity and harmfulness of the by-products, especially volatile organic compounds such as ethylbenzene, it is necessary to collect and treat the sealed emissions of each material storage tank and the residual liquid of the pump body to reduce environmental pollution. Therefore, an ethylbenzene recovery and treatment system for a POSM device is provided. Summary of the Invention

[0003] The purpose of the present invention is to address the deficiencies of the prior art and provide an ethylbenzene recovery and treatment system for a POSM device to solve the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solution: An ethylbenzene recovery and treatment system for a POSM device, including a ground tank, an ethylbenzene waste liquid discharge tank is provided inside the ground tank, a ground tank cover plate is provided on the top of the ground tank, a vacuum system is connected to the ground tank, and an ethylbenzene collection pipeline, a first nitrogen gas transmission pipeline, a second nitrogen gas transmission pipeline, a pressure detection and split range control device, a liquid level display device, a gas phase feeding line, and a liquid phase feeding line are connected to the top of the ethylbenzene waste liquid discharge tank;

[0005] A pressure compensation valve is installed on the first nitrogen gas transmission pipeline, a pressure relief valve is installed on the second nitrogen gas transmission pipeline, one end of the second nitrogen gas transmission pipeline is connected with a flame arrester, and a safety valve system is also connected to the second nitrogen gas transmission pipeline;

[0006] The liquid feed line and the gas feed line are both connected to the liquid discharge system. A gas sampling device and an orifice plate are provided on the gas feed line. An ethylbenzene discharge pump is installed on the liquid feed line. The liquid discharge system is connected to the HPW and the off-spec ethylbenzene tank. Drain line systems are connected to both the ethylbenzene discharge pump and the liquid discharge system, and the drain line systems are connected to the LPW system.

[0007] As a preferred technical solution of the present invention, the ethylbenzene collection pipeline is respectively connected to the off-spec ethylbenzene tank, the off-spec ethylbenzene tank pump, the fresh ethylbenzene tank and the fresh ethylbenzene tank pump.

[0008] As a preferred technical solution of the present invention, the flame arrester is connected to the VOC treatment system. The pressure relief valve and the pressure make-up valve are both solenoid valves. The pressure detection and split-range control device is electrically connected to the pressure relief valve and the pressure make-up valve respectively.

[0009] As a preferred technical solution of the present invention, the safety valve system includes a gas pipeline and two safety valves. The two safety valves are connected in parallel, and the gas pipeline connected to the safety valves is connected to the flare system.

[0010] As a preferred technical solution of the present invention, the gas sampling device is provided with a nitrogen purging device.

[0011] As a preferred technical solution of the present invention, the pressure detection and split-range control device includes a pressure sensor and a controller.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] The present invention can separately collect the waste liquid containing ethylbenzene materials in the POSM device in a storage tank. The gas pipeline in the storage tank is sent to the VOC treatment system, or the flare, or the HPW system to ensure that it is not discharged into the air. The liquid substances in the storage tank are pumped into the off-spec ethylbenzene tank for recycling. This not only reduces the loss of ethylbenzene, but also reduces the harm of ethylbenzene to operators during the production process.

[0014] During maintenance or when the pump body is emptied in the present invention, the residues in the gas and liquid pipelines in the storage tank are sent to the LPW system, reducing the emissions of the three wastes under abnormal conditions and truly achieving the closed discharge of the liquid phase and the gas phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the system of the present invention.

[0016] In the figure: 1 - underground tank; 2 - vacuum system; 3 - ethylbenzene collection pipeline; 4 - pressure detection and split-range control device; 401 - first nitrogen delivery pipeline; 402 - second nitrogen delivery pipeline; 403 - pressure relief valve; 404 - pressure make-up valve; 5 - safety valve system; 6 - liquid level display device; 7 - gas phase sampling device; 8 - orifice plate; 9 - flame arrester; 10 - liquid phase feeding line; 11 - ethylbenzene discharge pump; 12 - evacuation pipeline system; 13 - liquid phase discharge system; 14 - HPW; 15 - underground tank cover plate; 16 - ethylbenzene waste liquid discharge tank; 17 - gas phase feeding line. Detailed implementation mode

[0017] The following elaborates on the preferred embodiments of the present invention in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0018] Embodiment: Please refer to Figure 1 , the present invention provides a technical solution: an ethylbenzene recovery and treatment system for a POSM device, including an underground tank 1, an ethylbenzene waste liquid discharge tank 16 is arranged in the underground tank 1, an underground tank cover plate 15 is arranged on the top of the underground tank 1, a vacuum system 2 is connected to the underground tank 1, and an ethylbenzene collection pipeline 3, a first nitrogen delivery pipeline 401, a second nitrogen delivery pipeline 402, a pressure detection and split-range control device 4, a liquid level display device 6, a gas phase feeding line 17, and a liquid phase feeding line 10 are connected to the top of the ethylbenzene waste liquid discharge tank 16; the ethylbenzene is collected by the ethylbenzene collection pipeline 3, and the air pressure in the ethylbenzene waste liquid discharge tank 16 is adjusted by the first nitrogen delivery pipeline 401 and the second nitrogen delivery pipeline 402, the liquid level display device 6 displays the liquid level in the ethylbenzene waste liquid discharge tank 16, and the ethylbenzene in the ethylbenzene waste liquid discharge tank 16 is sent to an unqualified ethylbenzene tank for recycling or into the HPW 14 (highly polluted wastewater treatment system) through the gas phase feeding line 17 and the liquid phase feeding line 10.

[0019] A pressure make-up valve 404 is installed on the first nitrogen delivery pipeline 401, a pressure relief valve 403 is installed on the second nitrogen delivery pipeline 402, one end of the second nitrogen delivery pipeline 402 is connected to a flame arrester 9, and a safety valve system 5 is also connected to the second nitrogen delivery pipeline 402;

[0020] The liquid feed line 10 and the gas-phase feed line 17 are both connected to the liquid-phase discharge system 13. A gas-phase sampling device 7 and a choke orifice plate 8 are provided on the gas-phase feed line 17. An ethylbenzene discharge pump 11 is installed on the liquid feed line 10. The liquid-phase discharge system 13 is connected to HPW 14 and the off-spec ethylbenzene tank. Drain line systems 12 are connected to both the ethylbenzene discharge pump 11 and the liquid-phase discharge system 13. The drain line system 12 is connected to the LPW system (low-pollution wastewater treatment system). The drain line system 12 is arranged downstream of the gas-phase pipeline, so that when the liquid phase is drained, the materials purged from the gas-phase pipeline can also be collected into the LPW system. A blind plate is provided in the drain line system 12, which is opened when necessary and closed when not necessary, so that the materials in the LPW system will not flow back during normal production.

[0021] The ethylbenzene collection pipeline 3 is respectively connected to the off-spec ethylbenzene tank, the off-spec ethylbenzene tank pump, the fresh ethylbenzene tank and the fresh ethylbenzene tank pump, and the ethylbenzene in the off-spec ethylbenzene tank, the off-spec ethylbenzene tank pump, the fresh ethylbenzene tank and the fresh ethylbenzene tank pump is recovered by using the ethylbenzene collection pipeline 3.

[0022] The flame arrester 9 is connected to the VOC treatment system. The pressure relief valve 403 and the pressure make-up valve 404 are both solenoid valves. The pressure detection and split-range control device 4 is electrically connected to the pressure relief valve 403 and the pressure make-up valve 404 respectively. The pressure detection and split-range control device 4 detects the air pressure in the ethylbenzene waste liquid discharge tank 16 and controls the opening or closing of the pressure relief valve 403 and the pressure make-up valve 404.

[0023] The safety valve system 5 includes a gas-phase pipeline and two safety valves. The two safety valves are connected in parallel, and the gas-phase pipeline connected to the safety valves is connected to the flare system. The safety valve system is in the form of one in use and one in reserve to ensure safety.

[0024] The gas-phase sampling device 7 is provided with a nitrogen purging device. The gas-phase sampling device 7 is used to detect the composition of the gas-phase substances. The nitrogen purging device is to empty the sampling pipeline to prevent the risk of polymerization blockage caused by the residual liquid-phase materials.

[0025] The pressure detection and split-range control device 4 includes a pressure sensor and a controller. The pressure sensor can detect the air pressure in the ethylbenzene waste liquid discharge tank 16, and the controller can control the opening or closing of the pressure relief valve 403 and the pressure make-up valve 404.

[0026] Working principle: A POSM device ethylbenzene recovery and treatment system. This device mainly aims at recycling unqualified ethylbenzene and fresh ethylbenzene. The waste liquid in the unqualified ethylbenzene tank, the waste liquid discharged from the pump body of the unqualified ethylbenzene tank pump, the waste liquid in the fresh ethylbenzene tank, and the waste liquid discharged from the pump body of the fresh ethylbenzene tank pump are collected in the ethylbenzene waste liquid discharge tank 16 through the ethylbenzene collection pipeline 3. The ethylbenzene waste liquid discharge tank 16 is placed in the ground tank 1; the ground tank 1 contains a vacuum system 2 of the steam injection system, and a waste liquid discharge system of the waste liquid discharge pipeline LPW is connected to the vacuum system 2. The vacuum system 2 is used to pump the waste liquid in the ground tank into LPW for unified centralized treatment.

[0027] The ethylbenzene collected in the ethylbenzene waste liquid discharge tank 16 is stored under nitrogen seal through the pressure detection and split-range control device 4 to be stabilized within a suitable pressure range. When the pressure in the ethylbenzene waste liquid discharge tank 16 is too low, the nitrogen pressure make-up valve 404 opens and the pressure relief valve 403 closes. When the pressure in the ethylbenzene waste liquid discharge tank 16 is too high, the nitrogen pressure make-up valve 404 closes and the pressure relief valve 403 opens. Both the pressure make-up valve 404 and the pressure relief valve 403 are controlled by the pressure detection and split-range control device 4.

[0028] The gas phase is sent to the downstream VOC treatment system after passing through the flame arrester 9. At the same time, in order to prevent the pressure in the ethylbenzene waste liquid discharge tank 16 from being too high in other abnormal situations, a safety valve system 5 is added to the gas phase pipeline. The safety valve system adopts a one-use-one-spare form, and the gas phase pipeline of the safety valve is sent to the flare system. In addition, a liquid level display device 6 is set in the ethylbenzene waste liquid discharge tank 16. The liquid level display device 6 is a dual liquid level display, namely a radar liquid level gauge and a double flange liquid level gauge, which are used to detect the liquid level in the ethylbenzene waste liquid discharge tank 16 in real time. The purpose of setting the dual liquid level gauges is to reduce the production hidden dangers caused by the failure of a single liquid level gauge.

[0029] The liquid phase substances in the ethylbenzene waste liquid discharge tank 16 are sent to the unqualified ethylbenzene tank for recycling or to HPW through the ethylbenzene discharge pump 11 and the liquid phase discharge system 13. The liquid phase discharge system 13 sets a pressure gauge at the pump outlet to detect whether polymers are generated, and at the same time sets a check valve to prevent the risk of reverse flow of the liquid phase material. When the unqualified ethylbenzene tank cannot normally recycle the materials from the ethylbenzene waste liquid discharge tank 16, the liquid phase substances in the ethylbenzene waste liquid discharge tank 16 are sent to HPW. The dual feeding mode ensures normal production.

[0030] The gas phase substances in the ethylbenzene waste liquid discharge tank 16 are also sent to the unqualified ethylbenzene tank or HPW. A flow-limiting orifice plate 8 is set on the gas phase feeding pipeline to adjust the flow rate of the gas phase feeding pipeline. At the same time, a gas phase sampling device 7 with nitrogen purging is added at the gas phase pipeline to detect the composition of the gas phase substances.

[0031] When the pipeline needs to be emptied during shutdown for maintenance or other circumstances, the materials in the pipeline can be emptied through the emptying pipeline system 12. The emptying pipeline system 12 is arranged downstream of the gas phase pipeline, so that while the liquid phase is emptied, the materials emptied and purged from the gas phase pipeline can also be collected into the LPW system. When the ethylbenzene discharge pump 11 is repaired or otherwise offline, the materials remaining in the pump body are collected into the emptying pipeline system 12 as much as possible, and then sent to the downstream LPW for unified treatment. A blind plate is provided in the emptying pipeline system 12, which is opened when necessary and closed when not necessary, so that the materials in the LPW system will not be reversed during normal production.

[0032] The above embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A POSM device ethylbenzene recovery and processing system, comprising a ground tank (1), characterized in that: An ethylbenzene waste liquid discharge tank (16) is arranged in the floor tank (1), a floor tank cover plate (15) is arranged on the top of the floor tank (1), a vacuum system (2) is connected to the floor tank (1), and an ethylbenzene collection pipeline (3), a first nitrogen delivery pipeline (401), a second nitrogen delivery pipeline (402), a pressure detection and split-range control device (4), a liquid level display device (6), a gas phase feeding line (17), and a liquid phase feeding line (10) are connected to the top of the ethylbenzene waste liquid discharge tank (16); The first nitrogen delivery pipeline (401) is provided with a pressure relief valve (403), the second nitrogen delivery pipeline (402) is provided with a pressure relief valve (403), one end of the second nitrogen delivery pipeline (402) is connected to a flame arrester (9), and the second nitrogen delivery pipeline (402) is also connected to a safety valve system (5); The liquid phase feeding line (10) and the gas phase feeding line (17) are both connected to the liquid phase discharge system (13); the gas phase feeding line (17) is provided with a gas phase sampling device (7) and a flow limiting orifice (8); the liquid phase feeding line (10) is installed with an ethylbenzene discharge pump (11); the liquid phase discharge system (13) is connected to the HPW (14) and the unqualified ethylbenzene tank; the ethylbenzene discharge pump (11) and the liquid phase discharge system (13) are both connected to an emptying pipeline system (12); and the emptying pipeline system (12) is connected to the LPW system.

2. POSM device ethylbenzene recovery and treatment system according to claim 1, is characterized in that: The ethylbenzene collecting pipeline (3) is respectively connected to the unqualified ethylbenzene tank, the unqualified ethylbenzene tank pump, the fresh ethylbenzene tank and the fresh ethylbenzene tank pump.

3. POSM device ethylbenzene recovery and treatment system according to claim 1, is characterized in that: The flame arrester (9) is connected to the VOC treatment system, the pressure relief valve (403) and the pressure boosting valve (404) are both solenoid valves, and the pressure detection and split-range control device (4) is electrically connected to the pressure relief valve (403) and the pressure boosting valve (404) respectively.

4. POSM device ethylbenzene recovery and treatment system according to claim 1, is characterized in that: The safety valve system (5) comprises a gas phase pipeline and two safety valves, the two safety valves are connected in parallel, and the gas phase pipeline connected to the safety valves is connected to the flare system.

5. The POSM device ethylbenzene recovery and treatment system according to claim 1, wherein: The gas phase sampling device (7) is provided with a nitrogen purge device.

6. The POSM device ethylbenzene recovery and treatment system according to claim 1, wherein: The pressure detection and step-by-step control device (4) comprises a pressure sensor and a controller.

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