A pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas.

Abstract

This application discloses a pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas (LPG), comprising a column frame with a pretreatment group mounted on it. The pretreatment group, from top to bottom, includes a heat exchange group, a flash evaporation group, and a gravity sedimentation group. A feed group is connected to the end of the heat exchange group, and a guide plate with an S-shaped structure is installed within the heat exchange group to change the fluid flow direction and improve heat exchange efficiency. The lower outlet of the heat exchange group is connected to the inlet of the flash evaporation group. This device organically combines heat exchange regulation, flash evaporation separation, filtration interception, and two-stage gravity sedimentation, enabling continuous multi-stage removal of non-condensable gases and solid impurities within the same system. This effectively improves the purity of the LPG and ensures stable operation of subsequent processes. The S-shaped guide plate within the heat exchange group, through multiple bends, changes the fluid flow direction, enhances turbulence, improves heat exchange efficiency, and ensures that the LPG reaches optimal separation conditions before entering the flash evaporation group.

Description

Technical Field

[0001] This application relates to the field of liquefied petroleum gas (LPG) purification technology, specifically a pretreatment device for removing non-condensable gases from saturated LPG. Background Technology

[0002] Liquefied petroleum gas (LPG) is widely used in petrochemical, gas supply, and chemical production. However, during the production, storage, and transportation of LPG, non-condensable gases (such as nitrogen, air, and carbon dioxide) and solid impurities (such as rust, machine chips, and dust particles) often become mixed in. The presence of these non-condensable gases and impurities reduces the purity of the LPG, affects its combustion performance, and may also cause corrosion, scaling, and blockage in downstream equipment, potentially even jeopardizing the safe operation of the system in severe cases.

[0003] Existing liquefied petroleum gas (LPG) pretreatment units mostly employ a single physical separation method, such as flash evaporation to remove non-condensable gases or gravity settling to remove solid particles. However, these methods generally suffer from the following shortcomings: insufficient separation efficiency, as flash evaporation cannot completely remove fine air bubbles entrained in the liquid phase, resulting in residual non-condensable gases remaining in the LPG; incomplete impurity removal, as fixed-pore-size filter structures cannot simultaneously remove both coarse and fine particles, affecting the stability of subsequent processes; and difficulty in disassembling and assembling some units, requiring prolonged shutdowns for cleaning or replacing internal components, impacting production continuity. Summary of the Invention

[0004] The technical problem to be solved by this application is to overcome the existing defects and provide a pretreatment device for removing non-condensable gases from saturated liquefied gas, which can effectively solve the problems in the background art.

[0005] To achieve the above objectives, this application provides the following technical solution: a pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas (LPG), comprising a column frame, on which a pretreatment group is mounted, the pretreatment group consisting of a heat exchange group, a flash evaporation group, and a gravity sedimentation group arranged sequentially from top to bottom; a feed group is connected to the end of the heat exchange group, and a guide plate with an S-shaped structure is provided inside the heat exchange group to change the fluid flow direction and improve heat exchange efficiency; the lower outlet of the heat exchange group is connected to the inlet of the flash evaporation group, and a gas phase separator is provided at the upper end of the flash evaporation group to separate non-condensable gases from the liquid phase; the lower end of the flash evaporation group is connected to the gravity sedimentation group, and the gravity sedimentation group consisting of a filter group, a primary sedimentation unit, and a secondary sedimentation unit arranged sequentially from top to bottom, the filter group being located at the feed inlet of the gravity sedimentation group; and a switch valve group is provided at the discharge outlet of the gravity sedimentation group to control material flow.

[0006] As a preferred technical solution of this application, the S-shaped structure of the guide plate is formed by connecting multiple bent segments in sequence, and the included angle between adjacent bent segments is 60° to 120°.

[0007] As a preferred technical solution of this application, the guide plate is made of stainless steel or nickel-based alloy.

[0008] As a preferred technical solution of this application, the gas phase separator includes a cyclone separator, which is disposed at the upper inlet of the flash evaporation unit.

[0009] As a preferred technical solution of this application, the inner wall of the cyclone separator of the gas phase separator is provided with guide vanes, and the guide vanes are inclined at an angle of 40° to 80° with the axis of the cylinder.

[0010] As a preferred technical solution of this application, the filter group is a multi-layer metal mesh filter structure, and the filter pore size decreases from top to bottom, with a pore size range of 0.5mm to 5mm.

[0011] As a preferred technical solution of this application, the primary precipitation unit and the secondary precipitation unit are connected by a connecting pipe, and a control valve is provided on the connecting pipe.

[0012] As a preferred technical solution of this application, both the primary sedimentation unit and the secondary sedimentation unit are provided with slag discharge ports.

[0013] As a preferred technical solution of this application, the switching valve assembly is a low-temperature resistant ball valve and is equipped with an automatic control actuator to realize remote opening and closing control.

[0014] As a preferred technical solution of this application, the units of the pretreatment group are connected by flange joints.

[0015] Compared with the prior art, the beneficial effects of this application are: this device organically combines heat exchange regulation, flash separation, filtration interception and two-stage gravity sedimentation, which can continuously complete the multi-stage removal of non-condensable gas and solid impurities in the same system, effectively improve the purity of liquefied gas and ensure the stable operation of subsequent processes;

[0016] The heat exchange unit uses an S-shaped guide plate, which changes the fluid flow direction by bending multiple times, enhances the degree of turbulence, improves the heat exchange efficiency, and ensures that the liquefied gas reaches the optimal separation conditions before entering the flash evaporation unit.

[0017] The cyclone separator in the flash evaporation unit is equipped with inclined guide vanes, which can form a stable cyclone field and use centrifugal force to quickly separate and discharge non-condensable gases, resulting in high separation efficiency and low energy consumption.

[0018] The filter assembly adopts a multi-layer metal mesh structure with gradually decreasing pore size from top to bottom, which can intercept solid particles of different sizes in stages, reduce the subsequent settling burden, and prevent impurities from entering downstream equipment. The gravity sedimentation assembly is equipped with primary and secondary sedimentation units, and the flow rate and settling time can be adjusted through connecting pipes and control valves to further remove fine particles and ensure the cleanliness of liquefied gas. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this application;

[0020] Figure 2 This is the main view of this application;

[0021] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure at point AA;

[0022] Figure 4 for Figure 3 A magnified schematic diagram of the structure shown in section B.

[0023] In the diagram: 1. Column frame, 2. Feeding group, 3. Baffle plate, 4. Gas phase separator, 5. Cyclone separator, 6. Primary sedimentation unit, 7. Secondary sedimentation unit, 8. Switch valve group, 9. Filter group. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application (for ease of description and understanding, hereinafter referred to as...), Figure 2 (The above is described above). All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0025] Please see Figure 1-4 This application provides a technical solution: a pretreatment device for removing non-condensable gases from saturated liquefied gas, including a column frame 1. The column frame 1 is equipped with a heat exchange group, a flash evaporation group and a gravity sedimentation group from top to bottom. The units are connected by flange joints, which can ensure sealing and facilitate disassembly, maintenance and replacement of parts in the later stage.

[0026] The heat exchanger unit's inlet end is connected to a feed group 2, which can be directly connected to an upstream pipeline to introduce saturated liquefied gas into the system. Inside the heat exchanger unit, a guide vane 3 is arranged. The guide vane 3 has an S-shaped structure, composed of multiple sequentially connected bends, with the included angle between adjacent bends preferably within 90°. This structure forces the fluid to change direction multiple times during flow, thereby enhancing turbulence, increasing the heat transfer area and heat exchange time, and improving heat exchange efficiency. The guide vane 3 is preferably made of stainless steel or nickel-based alloy to ensure high strength and corrosion resistance under low temperature, high pressure, and corrosive media conditions. The lower outlet of the heat exchanger unit is connected to the inlet of the flash evaporation unit. Inside the upper end of the flash evaporation unit, a gas phase separator 4 is installed. The gas phase separator 4 includes a cyclone separator 5, which is installed at the upper inlet of the flash evaporation unit. Several guide vanes are evenly distributed on the inner wall of the cyclone separator 5, with the guide vanes inclined at an angle of 40° to 80° relative to the axis of the cylinder. When saturated liquefied petroleum gas (LPG) enters the cyclone separator 5, a high-speed rotating swirling field is formed under the action of the guide vanes. Centrifugal force concentrates the less dense non-condensable gas towards the axis, while the denser LPG is thrown towards the cylinder wall, thus achieving gas-liquid separation. The separated non-condensable gas can be discharged through the exhaust port at the top of the flash evaporation unit, while the liquid phase flows downward into the gravity sedimentation unit. This separation method has the advantages of compact structure, high separation efficiency, and low energy consumption, and is particularly suitable for processing LPG with high gas content.

[0027] The feed inlet of the gravity sedimentation unit is equipped with a filter group 9. The filter group 9 adopts a multi-layer metal mesh structure, with the pore size gradually decreasing from top to bottom, ranging from 0.5mm to 5mm.

[0028] Preferably, a three-layer structure is adopted, with the first layer of metal mesh having a mesh size of 1.5mm, the second layer of metal mesh having a mesh size of 1mm, and the third layer of metal mesh having a mesh size of 0.5mm.

[0029] This multi-stage filtration method removes larger particulate impurities before gravity settling, preventing the formation of an excessively thick sediment layer within the settling unit that could affect the settling effect. The outlet of filter group 9 is equipped with a switching valve group 8, which is a low-temperature resistant ball valve and features an automatic control actuator. This allows for remote opening and closing control, facilitating quick operation during maintenance, filter replacement, or material cutting.

[0030] The filtered liquefied petroleum gas (LPG) enters the primary sedimentation unit 6. Under gravity, suspended particles in the liquid phase gradually settle to the bottom of the unit and are periodically discharged through the slag discharge port. The primary sedimentation unit 6 and the secondary sedimentation unit 7 are connected by a connecting pipe equipped with a control valve to regulate the flow rate and liquid level balance between the two sedimentation stages. The secondary sedimentation unit 7 further removes fine particles that failed to settle in the primary sedimentation, significantly improving the purity of the discharged LPG. The slag discharge port of the sedimentation unit can be connected to an external slag storage container or sewage system for centralized recovery and treatment of impurities.

[0031] In use: Saturated liquefied gas enters the heat exchange group through the feed group 2, where it undergoes heat exchange under the action of the guide plate 3, and the temperature and pressure conditions are adjusted to a suitable flash evaporation state; then it enters the flash evaporation group, where non-condensable gases are efficiently separated in the cyclone separator 5; the separated liquid enters the gravity sedimentation group, and is processed by the multi-layer filter group 9 and the two-stage sedimentation unit to finally obtain high-purity liquefied gas with non-condensable gases and impurities removed, meeting the requirements of subsequent production or storage and transportation.

[0032] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas, comprising a column frame (1), characterized in that: The column frame (1) is equipped with a pretreatment group, which consists of a heat exchange group, a flash evaporation group and a gravity sedimentation group arranged from top to bottom. The heat exchange group is equipped with a guide plate (3), which is an S-shaped structure used to change the flow direction of the fluid. The lower outlet of the heat exchange group is connected to the inlet of the flash evaporation group. The upper end of the flash evaporation group is equipped with a gas phase separator (4). The lower end of the flash evaporation group is connected to the gravity sedimentation group. The gravity sedimentation group consists of a filter group (9), a primary sedimentation unit (6) and a secondary sedimentation unit (7) arranged from top to bottom. The filter group (9) is located at the inlet of the gravity sedimentation group. The outlet of the gravity sedimentation group is equipped with a switch valve group (8).

2. The pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas according to claim 1, characterized in that, The S-shaped structure of the guide plate (3) is formed by connecting multiple bent segments in sequence, and the included angle between adjacent bent segments is 60° to 120°.

3. A pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas according to claim 1 or 2, characterized in that, The guide plate (3) is made of stainless steel or nickel-based alloy.

4. The pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas according to claim 1, characterized in that, The gas phase separator (4) includes a cyclone separator (5), which is located at the upper inlet of the flash evaporation unit.

5. The pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas according to claim 4, characterized in that, The inner wall of the cyclone separator (5) of the gas phase separator (4) is provided with guide vanes, and the guide vanes are inclined at an angle of 40° to 80° with the axis of the cylinder.

6. The pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas according to claim 1, characterized in that, The filter group (9) is a multi-layer metal mesh filter structure, and the filter pore size decreases from top to bottom, with a pore size range of 0.5mm to 5mm.

7. The pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas according to claim 1, characterized in that, The primary sedimentation unit (6) and the secondary sedimentation unit (7) are connected by a connecting pipe, and a control valve is provided on the connecting pipe.

8. The pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas according to claim 1, characterized in that, Both the primary sedimentation unit (6) and the secondary sedimentation unit (7) are equipped with slag discharge ports.

9. A pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas according to claim 1, characterized in that, The switching valve assembly (8) is a low-temperature resistant ball valve.

10. A pretreatment device for removing non-condensable gases from saturated liquefied petroleum gas according to claim 1, characterized in that, The pretreatment units are connected by flange joints.

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