Ethylene compressor precooled material recovery device

Abstract

The utility model discloses an ethylene compressor precooling material recovery device, which comprises an ethylene loading storage tank, an ethylene loading pump, an ethylene compressor and an ethylene compressor first-section suction tank, and is characterized by further comprising an MTO (Methanol To Olefin) low-pressure recovery system, a first-section suction tank discharging pipeline is arranged at the low point of the first-section suction tank of the ethylene compressor, the ethylene loading storage tank is provided with an ethylene loading storage tank discharging pipeline, the ethylene loading pump discharging pipeline, the first-section suction tank discharging pipeline and the ethylene loading storage tank discharging pipeline are respectively connected to a recovery line, and the recovery line is connected with the MTO low-pressure recovery system. According to the device, on the premise that the operation of a single ethylene compressor is kept, when the ethylene compressor is precooled before being started, discharged materials are recycled, and meanwhile, the discharge of torch hydrocarbons is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of methanol to olefins (MTO), and relates to an ethylene compressor precooling material recovery device. Background Art

[0002] During the production process of the olefin separation unit, some ethylene products are often loaded and taken out through the low-temperature ethylene loading system. Ethylene loading is transported by low-pressure tank trucks, so the temperature of ethylene loading must be below -90°C, which places high requirements on the ethylene compressor. The startup of such ethylene compressors requires the inlet ethylene temperature to be reduced to below 0°C and at normal pressure, otherwise the ethylene compressor will be over-temperature interlocked or damaged. Because ethylene is not continuously loaded, the ethylene temperature in the ethylene loading tank is the normal ambient temperature under normal circumstances, so before the ethylene compressor is started, it is necessary to pre-cool the ethylene loading tank to the required temperature.

[0003] If the external sales of ethylene meet the premise of long-term ethylene loading, a small-load compressor can be added for pre-cooling, and the incoming ethylene temperature can be lowered before starting the ethylene compressor. However, many devices with downstream ethylene users have less or almost no loading. In the case of occasional external sales and loading, it is wasteful to configure another compressor. In this case, the ethylene is usually discharged to the flare from the remote low point of the ethylene loading system, and about 10 tons of ethylene needs to be vented to meet the compressor startup temperature requirements.

[0004] Putting materials directly into the flare causes waste of materials; at the same time, when the site is emptied and depressurized quickly, the flare will have certain combustion emissions, causing environmental pollution.

[0005] The current low-temperature ethylene loading system has the following shortcomings:

[0006] 1. Precooling the ethylene compressor before starting causes material loss and increases energy consumption of the device;

[0007] 2. When the ethylene compressor is precooled before starting, it causes flare emissions and combustion, which brings environmental pressure to the company.

[0008] For ethylene loading systems below -90°C, where a single ethylene compressor is running and loading is intermittent, improvements are urgently needed to avoid material loss and environmental pollution. Summary of the invention

[0009] The utility model aims to provide an ethylene compressor precooling material recovery device to solve the problems existing in the low-temperature ethylene loading system. When the ethylene compressor is precooled before starting, the discharged materials are recovered and recycled to the low-pressure system to realize the recovery of hydrocarbon products.

[0010] In order to achieve the above-mentioned invention object, the utility model adopts the following technical solutions:

[0011] An ethylene compressor precooling material recovery device comprises an ethylene loading tank, an ethylene loading pump, an ethylene compressor and a first suction tank of the ethylene compressor, characterized in that it also comprises an MTO low-pressure recovery system, an ethylene loading pump discharge pipeline is arranged in front of the ethylene loading pump, a first suction tank discharge pipeline is arranged at the low point of the first suction tank of the ethylene compressor, and an ethylene loading tank is arranged with an ethylene loading tank discharge pipeline, the ethylene loading pump discharge pipeline, the first suction tank discharge pipeline and the ethylene loading tank discharge pipeline are respectively connected to a recovery line, and the recovery line is connected to the MTO low-pressure recovery system.

[0012] Furthermore, the recovery line is connected to a product gas compressor suction tank of the MTO low-pressure recovery system.

[0013] Furthermore, the ethylene loading pump discharge pipeline, a section of the suction tank discharge pipeline and the ethylene loading tank discharge pipeline are respectively connected to the venting lines, and the venting lines are connected to the flare.

[0014] Furthermore, stop valves are respectively provided before the ethylene loading pump discharge pipeline, the first section suction tank discharge pipeline and the ethylene loading tank discharge pipeline are connected to the recovery line.

[0015] Furthermore, stop valves are respectively arranged before the ethylene loading pump discharge pipeline, a section of the suction tank discharge pipeline and the ethylene loading tank discharge pipeline are connected to the vent line.

[0016] Beneficial effects: For an ethylene loading system with intermittent loading operation, the ethylene compressor precooling material recovery device of the utility model can recover the discharged materials when the ethylene compressor is precooled before starting, and recover the hydrocarbon products to the low-pressure system. At the same time, it can reduce the emission of flare hydrocarbons and reduce environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of the ethylene compressor precooling material recovery device of the utility model;

[0018] Among them, 1. Ethylene tank area, 2. Ethylene loading storage tank, 3. Ethylene loading pump, 4. First-stage suction tank of ethylene compressor, 5. Ethylene loading pump discharge pipeline, 6. First-stage suction tank discharge pipeline, 7. Ethylene loading storage tank discharge pipeline, 8. Ethylene compressor, 9. Flare, 10. MTO low-pressure recovery system, 11. Ethylene storage tank truck, 12. Recovery line, 13. Vent line. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further described in detail below through specific embodiments. However, it is necessary to point out that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the protection scope of the present invention.

[0020] like Figure 1 The figure shows the structure of the ethylene compressor precooling material recovery device of the present invention.

[0021] The utility model of the ethylene compressor precooling material recovery device comprises an ethylene loading storage tank 2, an ethylene loading pump 3, an ethylene compressor 8 and an ethylene compressor first suction tank 4, characterized in that it also comprises an MTO low-pressure recovery system 10, an ethylene loading pump discharge pipeline 5 is arranged in front of the ethylene loading pump 3, a first suction tank discharge pipeline 6 is arranged at the low point of the first suction tank 4 of the ethylene compressor, and an ethylene loading storage tank discharge pipeline 7 is arranged on the ethylene loading storage tank 2, the ethylene loading pump discharge pipeline 5, the first suction tank discharge pipeline 6 and the ethylene loading storage tank discharge pipeline 7 are respectively connected to a recovery line 12 and a venting line 13 through respective stop valves, and the recovery line 12 is connected to the MTO low-pressure recovery system 10, specifically, to the MTO product gas compressor suction tank. The venting line 13 is connected to the flare 9.

[0022] The original material discharge process of precooling before starting the ethylene loading compressor is: ethylene compressor suction tank → low point flare valve → flare. The utility model is equipped with a new recovery line to the MTO low-pressure recovery point. At the same time, this pipeline runs through the surrounding of the loading system. This pipeline leads each discharge pipeline to each low point at intervals. The material recovery process is: precooling ethylene → ethylene compressor suction tank → each low point discharge line → recovery line → MTO low-pressure recovery system.

[0023] When precooling is required before the ethylene compressor is started, such as Figure 1 As shown, ethylene from the ethylene tank area 1 enters the ethylene loading tank 2, and the ethylene loading pump discharge pipeline 5, the first suction tank discharge pipeline 6, and the ethylene loading tank discharge pipeline 7 are connected to the vent line 13 by closing the stop valves, and the ethylene loading pump discharge pipeline 5, the first suction tank discharge pipeline 6, and the ethylene loading tank discharge pipeline 7 are connected to the recovery line 12. The ethylene is sent to the MTO low-pressure recovery system 10 of the preceding process section at a total of three locations, and the pressure and temperature are reduced to achieve pre-cooling and cooling of the ethylene loading tank 2, meet the start-up conditions of the ethylene compressor 8, and recover the vented ethylene to the preceding process section. The ethylene recovered to the low-pressure system can still be returned to the olefin separation device after being pressurized by the compressor to achieve the recovery of hydrocarbon products.

Claims

1. An ethylene compressor precooling material recovery device, comprising an ethylene loading tank (2), an ethylene loading pump (3), an ethylene compressor (8) and an ethylene compressor first stage suction tank (4), characterized in that: It also includes an MTO low-pressure recovery system (10), wherein an ethylene loading pump discharge pipeline (5) is arranged in front of the ethylene loading pump (3), a suction tank discharge pipeline (6) is arranged at the lower point of the first suction tank (4) of the ethylene compressor, and an ethylene loading tank discharge pipeline (7) is arranged on the ethylene loading tank (2). The ethylene loading pump discharge pipeline (5), the suction tank discharge pipeline (6) and the ethylene loading tank discharge pipeline (7) are respectively connected to a recovery line (12), and the recovery line (12) is connected to the MTO low-pressure recovery system (10).

2. The ethylene compressor precooling material recovery device according to claim 1, characterized in that: The recovery line (12) is connected to the product gas compressor suction tank of the MTO low-pressure recovery system (10).

3. The ethylene compressor precooling material recovery device according to claim 1, characterized in that: The ethylene loading pump discharge pipeline (5), a section of the suction tank discharge pipeline (6) and the ethylene loading tank discharge pipeline (7) are respectively connected to the vent line (13), and the vent line (13) is connected to the flare (9).

4. The ethylene compressor precooling material recovery device according to claim 1, characterized in that: Stop valves are respectively provided before the ethylene loading pump discharge pipeline (5), a section of the suction tank discharge pipeline (6) and the ethylene loading tank discharge pipeline (7) are connected to the recovery line (12).

5. The ethylene compressor precooling material recovery device according to claim 1, characterized in that: Stop valves are respectively provided before the ethylene loading pump discharge pipeline (5), a section of the suction tank discharge pipeline (6) and the ethylene loading tank discharge pipeline (7) are connected to the vent line (13).

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