Hexane recovery optimization system

Abstract

The utility model provides a hexane recovery optimization system, which relates to the field of low-pressure slurry polyethylene and comprises a liquid ring compressor, a gas-liquid conveying pipeline and a three-phase separator, the liquid ring compressor is connected with a three-phase separator through a gas-liquid conveying pipeline, one end of the three-phase separator is connected with a metering pipeline, and the other end of the metering pipeline is blocked through a blind plate; one end of the remote liquid level meter is communicated with a gas phase in the three-phase separator, and the other end of the remote liquid level meter is communicated with the metering pipeline. One end of the teletransmission liquid level meter is communicated with the gas phase of the three-phase separator, the other end of the teletransmission liquid level meter is isolated from the working liquid inlet pipeline, frequent fluctuation of the teletransmission liquid level meter is avoided, the phenomenon that the hexane content in working liquid is high due to unstable liquid level control is avoided, and therefore a stable liquid ring is formed in the liquid ring compressor.

Description

Technical Field

[0001] The utility model relates to the field of low-pressure slurry polyethylene, in particular to a hexane recovery optimization system. Background Art

[0002] In the powder purification unit in polyethylene production, the powder processing warehouse produces nitrogen, hexane, water, hydrogen chloride and hydrocarbon waste gases after processing the powder. In order to classify and recycle the waste gases, the above waste gases need to be passed into the spray tank to spray alkali solution to neutralize the acidic hydrogen chloride gas. Then the liquid phase and gas phase sprayed by the spray tank are transported to the three-phase separator through the liquid ring compressor for gas-liquid separation. The separated gas is passed into the gas separation membrane, and the mixed gas is recycled and processed separately. At this time, the main components of the liquid phase in the three-phase separator are liquid hexane and water. The liquid hexane and water are separated in the three-phase separator, and the hexane is separated and recycled.

[0003] When the liquid ring compressor is working, water needs to be continuously supplied to the liquid ring compressor to form a stable liquid ring. Conventional technical means use the water in the three-phase separator to transport it to the liquid ring compressor through the working fluid delivery pipeline. The three-phase separator must monitor the liquid level in the three-phase separator through a remote liquid level gauge. One end of the remote liquid level gauge is connected to the gas phase in the three-phase separator, and the other end is connected to the working fluid delivery pipeline. Since there is always liquid flowing in the working fluid delivery pipeline, the pointer of the remote liquid level gauge jumps, and the interface between water and hexane in the three-phase separator cannot be controlled in time. When the interface in the three-phase separator is too low, the water transported to the liquid ring compressor through the working fluid delivery pipeline contains some hexane. Due to the different densities of hexane and water, a stable liquid ring cannot be formed in the liquid ring compressor, causing the system to collapse. Utility Model Content

[0004] The utility model provides a hexane recovery optimization system, which solves the problem of high hexane content in working fluid caused by frequent fluctuations of the existing liquid level meter.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A hexane recovery optimization system comprises a liquid ring compressor, a gas-liquid conveying pipeline, and a three-phase separator; the liquid ring compressor is connected to the three-phase separator through the gas-liquid conveying pipeline, the gas outlet of the three-phase separator is connected to one end of a gas phase discharge pipeline, and the other end of the gas phase discharge pipeline is connected to a membrane recovery system; the liquid outlet of the three-phase separator is connected to an ethane tank through an ethane liquid discharge pipeline; one end of the three-phase separator is connected to a metering pipeline, and the other end of the metering pipeline is blocked by a blind plate; one end of a remote liquid level gauge is communicated with the gas phase inside the three-phase separator, and the other end of the remote liquid level gauge is communicated with the metering pipeline.

[0007] Furthermore, a first hand valve and a second hand valve are respectively arranged on the gas-liquid delivery pipeline, the first hand valve is arranged on the gas-liquid delivery pipeline near one end of the liquid ring compressor, and the second hand valve is arranged on the gas-liquid delivery pipeline near one end of the three-phase separator.

[0008] Furthermore, the liquid inlet of the three-phase separator is connected to one end of a working liquid replenishment line, and the component of the working liquid in the working liquid replenishment line is desalted water.

[0009] Furthermore, the water outlet of the three-phase separator is connected to the liquid ring compressor through a liquid ring compressor replenishing pipeline, and a working liquid cooler, a third manual valve and a fourth manual valve are arranged on the liquid ring compressor replenishing pipeline.

[0010] Furthermore, the third manual valve is arranged on the liquid ring compressor replenishing pipeline at the liquid inlet of the working liquid cooler, and the fourth manual valve is arranged on the liquid ring compressor replenishing pipeline at the liquid outlet of the working liquid cooler.

[0011] Furthermore, the liquid ring compressor replenishment pipeline is connected to one end of the working fluid wastewater discharge pipeline, and the other end of the working fluid wastewater discharge pipeline is connected to the wastewater pipeline.

[0012] Furthermore, the liquid ring compressor replenishment pipeline is connected to one end of the parking replenishment pipeline, the other end of the parking replenishment pipeline is connected to the liquid ring compressor, and the parking replenishment pipeline is provided with a fifth manual valve and a flow meter.

[0013] The beneficial effects of the utility model are:

[0014] The utility model connects one end of the remote liquid level meter with the gas phase of the three-phase separator to isolate the remote liquid level meter from the working liquid inlet pipeline, thereby avoiding frequent fluctuations of the remote liquid level meter and the phenomenon of high hexane content in the working liquid caused by unstable liquid level control, thereby forming a stable liquid ring in the liquid ring compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the utility model or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a schematic diagram of the overall system of the utility model.

[0017] Description of Figure Numbers:

[0018] 1. Liquid ring compressor; 2. Three-phase separator; 3. Gas-liquid transmission pipeline; 4. Metering pipeline; 5. Remote liquid level gauge; 6. Blind plate; 7. Liquid ring compressor refilling pipeline; 8. Working fluid cooler; 9. Working fluid wastewater discharge pipeline; 10. Parking refilling pipeline; 11. Working fluid water replenishing line. DETAILED DESCRIPTION

[0019] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the utility model and its application or use. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0021] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0022] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the utility model. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0023] In the description of the present utility model, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present utility model and simplifying the description. Unless otherwise stated, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present utility model: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0024] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0025] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the utility model.

[0026] The utility model provides a technical solution: a hexane recovery optimization system, such as Figure 1 As shown, it includes a liquid ring compressor 1, a gas-liquid transmission pipeline 3, a three-phase separator 2, and a working liquid water replenishment line;

[0027] The liquid ring compressor 1 compresses the gas delivered from the spray tank after neutralization treatment and performs pressurization treatment. The inlet pressure of the liquid ring compressor 1 is about 3-4KPa, and the outlet pressure is about 0.5MPa.

[0028] The gas-liquid delivery pipeline 3 is used to connect the liquid ring compressor 1 with the three-phase separator 2 . The gas phase and liquid phase compressed by the liquid ring compressor 1 are delivered to the three-phase separator 2 through the gas-liquid delivery pipeline 3 .

[0029] The three-phase separator 2 is connected to the liquid ring compressor 1 through the gas-liquid transmission pipeline 3, and separates the gas phase and the liquid phase transmitted by the liquid ring compressor 1, wherein the liquid phase component is liquid phase hexane, the main component of the gas phase is nitrogen, and the gas phase hexane (the gas phase component also contains water vapor and chloride ions).

[0030] The first hand valve is arranged on the gas-liquid delivery pipeline 3 and is located near the gas outlet of the liquid ring compressor 1, so that the gas phase and the liquid phase in the gas-liquid delivery pipeline 3 flow to the three-phase separator 2 or stop and control the flow rate.

[0031] The second hand valve is arranged on the gas-liquid delivery pipeline 3 and is located near the liquid-gas inlet position of the three-phase separator 2, so that the gas phase and liquid phase in the gas-liquid delivery pipeline 3 flow to the three-phase separator 2 or stop and control their flow rate.

[0032] The gas phase discharge pipeline has one end connected to the gas outlet of the three-phase separator 2, and the other end connected to the membrane recovery system. After separation in the three-phase separator 2, the gas phase is transported to the membrane recovery system through the gas phase discharge pipeline for gas phase separation. The main component structure of the membrane recovery system is the separation membrane, which separates gases of different densities respectively through the separation membrane to realize the gas recovery function of different components.

[0033] One end of the hexane discharge pipeline is connected to the three-phase separator 2, and the other end is connected to the hexane tank. The liquid hexane in the three-phase separator 2 is discharged from the three-phase separator 2 through the hexane discharge pipeline, thereby realizing the separation and recovery of the liquid hexane.

[0034] The working liquid replenishment line 11, one end of which is connected to the three-phase separator 2, is used to replenish the working liquid in the three-phase separator 2 in real time. The working liquid is composed of desalted water. Since the waste gas generated by the powder processing bin contains acidic gas, it enters the spray tower for alkaline liquid spraying. After a long period of work, the liquid phase transported to the three-phase separator 2 via the liquid ring compressor 1 will be in an acid-base imbalance state, and the liquid level in the three-phase separator 2 must be controlled to ensure a certain height so that the liquid phase hexane and water can be successfully separated. Therefore, the working liquid must be introduced into the three-phase separator 2 in real time according to different working conditions.

[0035] The liquid ring compressor replenishing pipeline 7 is connected to the three-phase separator 2 at one end and to the liquid ring compressor 1 at the other end. The liquid ring compressor replenishing pipeline 7 is used to connect the three-phase separator 2 with the liquid ring compressor 1. During the operation of the liquid ring compressor 1, the working fluid inside it will be discharged from the liquid ring compressor 1 along with the compressed gas, so it is necessary to replenish the working fluid into the liquid ring compressor 1. The composition of the working fluid in the liquid ring compressor 1 is the same as that in the three-phase separator 2, and both are desalted water.

[0036] The metering pipeline 4 has one end connected to the three-phase separator 2 and the other end blocked by a blind plate 6. The metering pipeline 4 is used to cooperate with the remote level meter 5 to monitor the liquid level in the three-phase separator 2.

[0037] The remote level gauge 5 has one end connected to the three-phase separator 2 and the other end connected to the metering pipeline 4. The remote level gauge 5 monitors the liquid level of the three-phase separator 2. The end of the remote level gauge 5 connected to the three-phase separator 2 is connected to the gas phase inside the three-phase separator 2. Since there is no liquid flowing in the metering pipeline 4, the end of the remote level gauge 5 connected to the metering pipeline 4 measures the pressure value of the static liquid inside the metering pipeline 4, which solves the technical problem of the pointer jumping of the remote level gauge 5 and greatly improves the measurement accuracy of the remote level gauge 5. The remote level gauge 5 can transmit the liquid level data in the three-phase separator 2 to the control system.

[0038] The system also includes a working fluid cooler 8, a third hand valve, and a fourth hand valve, which are all arranged on the liquid ring compressor replenishment pipeline 7, the third hand valve is located at the inlet position of the working fluid cooler 8, and the fourth hand valve is located at the outlet position of the working fluid cooler 8. When the working fluid in the three-phase separator 2 needs to be transported to the liquid ring compressor 1, the third hand valve and the fourth hand valve should be opened first, and the working fluid in the three-phase separator 2 is cooled by the working fluid cooler 8 and then passed into the liquid ring compressor 1;

[0039] It also includes a working liquid wastewater discharge pipeline 9, one end of which is connected to the liquid ring compressor replenishment pipeline 7, and the other end is connected to the wastewater pipeline. Since the liquid phase after spraying by the spray tank has an acid-base imbalance, the liquid phase after spraying is transported to the three-phase separator 2 through the liquid ring compressor 1, so that the working liquid in the three-phase separator 2 has an acid-base imbalance problem. At this time, part of the working liquid needs to be discharged to the outside of the three-phase separator 2. The working liquid with acid-base imbalance is transported to the working liquid wastewater discharge pipeline 9 through the compressor replenishment pipeline 7 and discharged from the three-phase separator 2;

[0040] It also includes a stop-liquid replenishment pipeline 10, a fifth hand valve, and a flow meter. One end of the stop-liquid replenishment pipeline 10 is connected to the liquid ring compressor replenishment pipeline 7, and the other end is connected to the liquid ring compressor 1. The fifth hand valve and the flow meter are both arranged on the stop-liquid replenishment pipeline 10. Before the liquid ring compressor 1 starts working, a certain liquid level is required in the liquid ring compressor 1. The fifth hand valve is opened, and the third and fourth hand valves are closed to transport the working fluid in the three-phase separator 2 to the liquid ring compressor 1 through the stop-liquid replenishment pipeline 10.

[0041] The working principle of this utility model:

[0042] Before the liquid ring compressor 1 starts working, open the fifth hand valve, close the third hand valve and the fourth hand valve, and transport the working fluid from the three-phase separator 2 to the liquid ring compressor 1 through the parking and replenishing pipeline 10. After the above preparations are completed, open the first hand valve and the second hand valve, and the gas phase and liquid phase neutralized by the spray tank are transported to the three-phase separator 2 through the liquid ring compressor 1 through the gas-liquid transport pipeline 3. The three-phase separator 2 separates the transported gas phase and liquid phase, and the gas phase is transported to the membrane recovery system through the gas phase discharge pipeline for separation and recovery; the liquid phase hexane and water are separated in the three-phase separator 2, and the separated liquid phase hexane is transported to the hexane tank through the hexane discharge pipeline. The remote level meter 5 detects the liquid level in the three-phase separator 2. When the liquid level in the three-phase separator 2 is too low, the working fluid is replenished into the three-phase separator 2 through the working liquid replenishing line 11. Since the remote level gauge 5 is connected to the gas phase in the three-phase separator 2 and the other end is connected to the metering pipeline 4, the remote level gauge 5 does not have the technical problem of inaccurate measurement caused by pointer fluctuation. When the working fluid in the liquid ring compressor 1 needs to be replenished, open the third hand valve and the fourth hand valve, close the fifth hand valve, and the three-phase separator 2 continuously replenishes the liquid ring compressor 1 through the liquid ring compressor replenishment pipeline 7. When the working fluid in the three-phase separator 2 has an imbalance in pH, close the third hand valve, the fourth hand valve, and the fifth hand valve, and discharge the working fluid in the three-phase separator 2 through the working fluid wastewater pipeline 9.

[0043] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes within the technical scope disclosed by the present invention according to the technical solution and inventive concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A hexane recovery optimization system, characterized in that: The invention comprises a liquid ring compressor (1), a gas-liquid transmission pipeline (3), and a three-phase separator (2); the liquid ring compressor (1) is connected to the three-phase separator (2) through the gas-liquid transmission pipeline (3); the gas outlet of the three-phase separator (2) is connected to one end of a gas phase discharge pipeline, and the other end of the gas phase discharge pipeline is connected to a membrane recovery system; the liquid outlet of the three-phase separator (2) is connected to an ethane tank through an ethane liquid discharge pipeline; one end of the three-phase separator (2) is connected to a metering pipeline (4), and the other end of the metering pipeline (4) is blocked by a blind plate (6); one end of a remote liquid level gauge (5) is connected to the gas phase inside the three-phase separator (2), and the other end of the remote liquid level gauge (5) is connected to the metering pipeline (4).

2. The hexane recovery optimization system according to claim 1, characterized in that: A first hand valve and a second hand valve are respectively arranged on the gas-liquid delivery pipeline (3), wherein the first hand valve is arranged on the gas-liquid delivery pipeline (3) close to one end of the liquid ring compressor (1), and the second hand valve is arranged on the gas-liquid delivery pipeline (3) close to one end of the three-phase separator (2).

3. The hexane recovery optimization system according to claim 1, characterized in that: The liquid inlet of the three-phase separator (2) is connected to one end of a working liquid replenishment line (11), and the working liquid in the working liquid replenishment line (11) contains desalted water.

4. The hexane recovery optimization system according to claim 1, characterized in that: The water outlet of the three-phase separator (2) is connected to the liquid ring compressor (1) via a liquid ring compressor replenishing pipeline (7), and a working liquid cooler (8), a third manual valve and a fourth manual valve are provided on the liquid ring compressor replenishing pipeline (7).

5. The hexane recovery optimization system according to claim 4, characterized in that: The third hand valve is arranged on the liquid ring compressor replenishing pipeline (7) at the liquid inlet of the working liquid cooler (8), and the fourth hand valve is arranged on the liquid ring compressor replenishing pipeline (7) at the liquid outlet of the working liquid cooler (8).

6. The hexane recovery optimization system according to claim 4, characterized in that: The liquid ring compressor replenishment pipeline (7) is connected to one end of the working fluid wastewater discharge pipeline (9), and the other end of the working fluid wastewater discharge pipeline (9) is connected to the wastewater pipeline.

7. The hexane recovery optimization system according to claim 4, characterized in that: The liquid ring compressor refilling pipeline (7) is connected to one end of a stop refilling pipeline (10), and the other end of the stop refilling pipeline (10) is connected to the liquid ring compressor (1). A fifth manual valve and a flow meter are provided on the stop refilling pipeline (10).

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