Oil and gas separation device for compressed natural gas filling system

Abstract

An oil-gas separation device for a compressed natural gas filling system includes a pressure vessel shell provided with an air inlet and an air outlet, a partition is arranged in the cavity of the pressure vessel shell, and the inner cavity of the pressure vessel shell is divided into an upper cavity and a lower cavity, the upper cavity is an oil-gas separation cavity, and the lower cavity is an oil accumulation cavity, the partition is supported by a supporting structure arranged in the oil accumulation cavity, an oil-through hole penetrating from top to bottom is arranged on the partition, a coalescing filter element is arranged in the oil-gas separation cavity, the upper end of the coalescing filter element is fixedly connected to the cavity top of the pressure vessel shell, and is connected to the air inlet of the pressure vessel shell, the lower end of the coalescing filter element is suspended and does not contact the partition, and an air-through space is left between the outer wall of the coalescing filter element and the inner wall of the pressure vessel shell, the air-through space is connected to the air outlet, and an oil row hole is arranged at the bottom of the oil accumulation cavity. The oil mist mixed in the compressed natural gas is fully separated and filtered, the oil mist mixed in the compressed natural gas is eliminated, and the oil mist is prevented from being added to the gas storage tank of the vehicle along with the compressed natural gas.

Description

Technical Field

[0001] The invention relates to the field of natural gas filling, and in particular to an oil-gas separation device of a compressed natural gas filling system. Background Art

[0002] Before natural gas enters the gas station's gas dispenser, a hydraulic booster is used to increase the gas pressure to 20-25MPa to ensure that the natural gas added to the vehicle's gas tank has sufficient pressure. When the natural gas filling station uses a hydraulic compressor to compress the natural gas, the hydraulic oil and natural gas are in direct contact in the hydraulic compressor, so a certain amount of hydraulic oil will be mixed in the compressed high-pressure gas. To solve this problem, a buffer tank is currently installed on the compressed natural gas transmission pipeline. The buffering effect of the buffer tank is used to buffer and stabilize the compressed natural gas in the inner cavity of the buffer tank. At the same time, during the buffering process of the compressed natural gas in the tank, the larger mixed oil droplets settle to the bottom of the buffer tank, achieving preliminary separation of oil and gas, so that the natural gas can be output through the outlet at the upper end of the buffer tank. However, since natural gas generates heat during the compression process, the hydraulic oil heats up and generates oil mist mixed in the compressed natural gas. After the oil mist mixed in the compressed natural gas enters the buffer tank, it will not cool down in a short time to form oil droplets and separate from the natural gas. A considerable part of the oil mist will still be mixed in the compressed natural gas and output and added to the vehicle's gas tank. Especially when the natural gas filling station is in the situation where multiple vehicles are filling gas at the same time, the flow rate of compressed natural gas output from the buffer tank increases, and the time for compressed natural gas to pass through the buffer tank is shortened. The oil mist mixed in the compressed natural gas is more difficult to form oil droplets and separate from the natural gas. The oil mist will be rapidly output from the buffer tank with the air flow and added to the vehicle's gas tank. Once the oil mist enters the vehicle's gas tank, it will be cooled to form oil liquid and accumulate in the gas tank. Over time, a large amount of oil liquid will gather and occupy the gas tank space, causing the gas storage capacity of the vehicle's gas tank to gradually decrease, affecting the vehicle's cruising range. Therefore, the natural gas filling system can no longer effectively separate the oil mist mixed in the compressed natural gas by relying solely on the buffer tank.

[0003] At present, although there are oil-gas separation devices of different structures on the market, the oil-gas separation devices usually recover the oil through separation filtration, and discharge the gas generated by the oil in the working environment into the atmosphere. These oil-gas separation devices cannot solve the problem of separating oil mist in compressed natural gas at natural gas filling stations. Summary of the invention

[0004] The purpose of the present invention is to provide an oil-gas separation device for a compressed natural gas filling system in view of the corresponding deficiencies in the prior art, which can fully separate and filter the oil mist mixed in the compressed natural gas, eliminate the oil mist mixed in the compressed natural gas, and prevent the oil mist from being added to the vehicle's gas tank along with the compressed natural gas.

[0005] The objective of the present invention is achieved by adopting the following scheme: an oil-gas separation device of a compressed natural gas filling system, comprising a pressure vessel shell provided with an air inlet and an air outlet, a partition is arranged in the cavity of the pressure vessel shell, the inner cavity of the pressure vessel shell is divided into an upper cavity and a lower cavity by the partition, the upper cavity is an oil-gas separation cavity, and the lower cavity is an oil accumulation cavity, the partition is supported by a supporting structure arranged in the oil accumulation cavity, an oil through hole penetrating from top to bottom is arranged on the partition, a coalescing filter element is arranged in the oil-gas separation cavity, the upper end of the coalescing filter element is fixedly connected to the cavity top of the pressure vessel shell, and is connected to the air inlet of the pressure vessel shell, the lower end of the coalescing filter element is suspended and does not contact with the partition, an air passing space is left between the outer wall of the coalescing filter element and the inner wall of the pressure vessel shell, the air passing space is communicated with the air outlet, and an oil drain hole is arranged at the cavity bottom of the oil accumulation cavity.

[0006] The upper surface of the partition plate is provided with a groove, and the oil hole is located at the bottom of the groove.

[0007] The groove is a conical groove, and the conical surface of the conical groove is a guide surface for collecting hydraulic oil.

[0008] The supporting structure at the lower end of the partition is a compression spring, the upper end of the compression spring is in contact with the partition, and the lower end of the compression spring is in contact with the cavity bottom of the pressure vessel shell.

[0009] The supporting structure at the lower end of the partition is a plurality of columns, the upper ends of the columns are in contact with the partition, and the lower ends are fixed to the cavity bottom of the pressure vessel shell.

[0010] An upper end cover is provided at the upper end of the pressure vessel shell, which is fixedly connected and sealed to the pressure vessel shell, the air inlet and the air outlet are both arranged on the upper end cover, and a lower end cover is provided at the lower end of the pressure vessel shell, which is fixedly connected and sealed to the pressure vessel shell, and the oil drain hole is arranged on the lower end cover.

[0011] The lower end surface of the upper end cover is provided with a mounting groove for fixing the coalescing filter element, the air inlet is communicated with the mounting groove, an air passing annular groove is provided on the periphery of the mounting groove, and the air outlet is communicated with the air passing annular groove.

[0012] The upper end surface of the lower end cover is provided with a positioning hole for installing the supporting structure.

[0013] The diameter of the oil hole is 5 to 30 mm.

[0014] The present invention includes the following beneficial effects: it includes a pressure vessel shell provided with an air inlet and an air outlet, a partition is arranged in the cavity of the pressure vessel shell, the inner cavity of the pressure vessel shell is divided into an upper cavity and a lower cavity by the partition, the upper cavity is an oil-gas separation cavity, the lower cavity is an oil accumulation cavity, the partition is supported by a supporting structure arranged in the oil accumulation cavity, an oil-through hole penetrating from top to bottom is arranged on the partition, a coalescing filter element is arranged in the oil-gas separation cavity, the upper end of the coalescing filter element is fixedly connected to the cavity top of the pressure vessel shell, and is connected to the air inlet of the pressure vessel shell, the lower end of the coalescing filter element is suspended and does not contact the partition, an air-through space is left between the outer wall of the coalescing filter element and the inner wall of the pressure vessel shell, the air-through space is communicated with the air outlet, and an oil drain hole is arranged at the bottom of the oil accumulation cavity. After the compressed natural gas mixed with oil mist enters the coalescing filter element from the air inlet of the pressure vessel shell, the oil mist mixed in the compressed natural gas is coalesced by the coalescing filter element into larger oil droplets separated from the compressed natural gas. The oil droplets drip onto the upper end surface of the partition under the action of gravity and enter the oil accumulation chamber from the oil through hole of the partition. At the same time, the separated compressed natural gas enters the oil-gas separation chamber from the gap of the coalescing filter element and is output from the air outlet. Due to the effect of the partition, the oil liquid entering the oil accumulation chamber can no longer enter the oil-gas separation chamber and mix with the compressed natural gas; since the oil liquid in the oil accumulation chamber can no longer form oil mist, the oil liquid gathered in the oil accumulation chamber can be discharged from the oil drain hole.

[0015] The upper end surface of the partition is provided with a groove, and the oil passage hole is located at the bottom of the groove. The groove can collect oil droplets to enter the oil accumulation cavity from the oil passage hole.

[0016] The groove is a conical groove, the conical surface of which is a guide surface for collecting hydraulic oil, and the guide surface allows the separated oil droplets to quickly enter the oil accumulation chamber from the oil passing hole.

[0017] The support structure at the lower end of the partition is a compression spring, the upper end of which contacts the partition, and the lower end contacts the bottom of the pressure vessel shell. The use of a compression spring to support the partition can avoid the problems caused by welding or screwing the partition to the pressure vessel shell, because when the partition is fixed to the inner cavity of the pressure vessel shell by welding, the pressure vessel shell will undergo significant changes in structure and performance at high temperatures, reducing the pressure resistance and actual life of the pressure vessel, and even causing explosions in severe cases, endangering life and property safety; and fixing the partition and the pressure vessel shell with multiple screws will reduce the sealing of the pressure vessel, easily causing compressed natural gas leakage, and seriously affecting the working quality of the pressure vessel. The use of a compression spring to support the partition can also enable the partition to move up and down when under pressure, balancing the air pressure of the oil-gas separation chamber and the oil accumulation chamber, thereby protecting the partition.

[0018] An upper end cover is provided at the upper end of the pressure vessel shell, which is fixedly connected and sealed to the pressure vessel shell. The air inlet and the air outlet are both arranged on the upper end cover. A lower end cover is provided at the lower end of the pressure vessel shell, which is fixedly connected and sealed to the pressure vessel shell. The oil drain hole is arranged on the lower end cover, which is conducive to the installation of the coalescing filter element, the partition plate, and the supporting structure.

[0019] The lower end surface of the upper end cover is provided with a mounting groove for fixing the coalescing filter element, the air inlet is connected with the mounting groove, the outer periphery of the mounting groove is provided with an air passing annular groove, the air outlet is connected with the air passing annular groove, so as to ensure the flow balance of the natural gas flow flowing through the air outlet and the air inlet.

[0020] The diameter of the oil hole is 5-30 mm, and the diameter of the oil hole is set according to the volume of the pressure container shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention;

[0022] Figure 2 It is a structural schematic diagram of the upper end cover of the present invention. DETAILED DESCRIPTION

[0023] like Figure 1 to Figure 2As shown, an oil-gas separation device of a compressed natural gas filling system includes a pressure vessel shell 3 provided with an air inlet 1 and an air outlet 2, a partition 4 is arranged in the cavity of the pressure vessel shell 3, and the inner cavity of the pressure vessel shell 3 is divided into an upper cavity and a lower cavity by the partition 4, the upper cavity is an oil-gas separation cavity 5, and the lower cavity is an oil accumulation cavity 6, the partition 4 is supported by a supporting structure arranged in the oil accumulation cavity 6, and the partition 4 is provided with an oil through hole 7 penetrating from top to bottom, the aperture of the oil through hole 7 is 5 to 30 mm, and the aperture size of the oil through hole 7 is set according to the volume of the pressure vessel shell 3. In this embodiment, the upper end surface of the partition 4 is provided with a groove 10, and the oil through hole 7 is located at the bottom of the groove 10, and the groove 10 can collect oil droplets from the oil through hole 7 to enter the oil accumulation cavity 6. The groove 10 is a conical groove, and the conical surface of the conical groove is a guide surface for collecting hydraulic oil, and the guide surface allows the separated oil droplets to quickly enter the oil accumulation cavity 6 from the oil through hole 7. A coalescing filter element 8 is arranged in the oil-gas separation chamber 5, and the upper end of the coalescing filter element 8 is fixedly connected to the cavity top of the pressure vessel shell 3, and is connected to the air inlet 1 of the pressure vessel shell 3, and the lower end of the coalescing filter element 8 is suspended and not in contact with the partition 4. An air space is left between the outer wall of the coalescing filter element 8 and the inner wall of the pressure vessel shell 3, and the air space is communicated with the air outlet 2. An oil drain hole 9 is arranged at the bottom of the oil accumulation chamber 6. When in use, a stop valve is arranged on the oil drain pipe connected to the oil drain hole 9. The oil accumulated in the oil accumulation chamber 6 can be discharged by opening the stop valve. The upper end of the pressure vessel shell 3 of this embodiment is provided with an upper end cover 12, which is fixedly connected and sealed to the pressure vessel shell 3. The air inlet 1 and the air outlet 2 are both arranged on the upper end cover 12. The lower end surface of the upper end cover 12 is provided with a mounting groove 14 for fixing the coalescing filter element 8. The air inlet 1 is connected to the mounting groove 14. The coalescing filter element 8 is fixed in the mounting groove 14 by threaded fitting connection, or the coalescing filter element 8 can also be fixed in the mounting groove 14 by bonding. The outer periphery of the mounting groove 14 of the upper end cover 12 is provided with an air-passing annular groove 15, and the air outlet 2 is connected to the air-passing annular groove 15. The coalescing filter element 8 is fixed in the mounting groove 14 of the upper end cover 12, and the upper end cover 12 can be opened to remove the coalescing filter element 8 for cleaning or replacement. The lower end of the pressure vessel shell 3 is provided with a lower end cover 13, which is fixedly connected and sealed to the pressure vessel shell 3. The oil drain hole 9 is arranged on the lower end cover 13. The upper end cover 12 and the lower end cover 13 can be connected and fixed to the pressure vessel shell 3 by threads, or the pressure vessel shell 3 can be clamped and fixed in the middle by long bolts passing through the upper end cover 12 and the lower end cover 13 (not shown). The assembly gap between the end faces of the upper end cover 12 and the lower end cover 13 and the pressure vessel shell 3 is sealed, and the sealing can be made by high-precision processing of the sealing surface, or by sealing with a sealing ring.

[0024] In this embodiment, the support structure at the lower end of the partition 4 adopts a compression spring 11, the upper end of the compression spring 11 contacts the partition 4 and supports the partition 4, and the lower end of the compression spring 11 contacts the cavity bottom of the pressure vessel shell 3 and abuts the lower end cover 13. The upper end surface of the lower end cover 13 is provided with a positioning hole for installing the support structure, the positioning hole is a circular groove, the lower end of the compression spring 11 is fixed in the circular groove to form a positioning, and the oil drain hole 9 is provided at the groove bottom of the circular groove. Alternatively, the support structure at the lower end of the partition 4 adopts a plurality of columns (not shown), the upper end of the column contacts the partition 4 and supports the partition 4, and the lower end of the column is connected and fixed to the lower end cover 13 of the pressure vessel shell 3. The upper end surface of the lower end cover 13 is provided with a positioning hole for installing the support structure, the positioning hole is a threaded blind hole, the number of the positioning holes is the same as the number of the columns, and the lower end of the column is fixed in the threaded blind hole by threaded cooperation.

[0025] When assembling the oil-gas separation device of the compressed natural gas filling system, first install the partition 4 into the inner cavity of the pressure vessel shell 3, fix the lower end of the compression spring 11 in the circular groove provided on the upper end surface of the lower end cover 13, install the lower end cover 13 at the lower end of the pressure vessel shell 3, make the upper end of the compression spring 11 support the partition 4, support the partition 4 in the cavity of the pressure vessel shell 3, and divide the inner cavity of the pressure vessel shell 3 into the oil-gas separation cavity 5 and the oil accumulation cavity 6. Fix the coalescing filter element 8 to the upper end cover 12, install the upper end cover 12 at the upper end of the pressure vessel shell 3, and insert the coalescing filter element 8 into the oil-gas separation cavity 5 of the pressure vessel shell 3. In this way, many disadvantages existing in the case where the partition 4 is fixed to the inner cavity of the pressure vessel shell 3 by welding or screws can be avoided.

[0026] When in use, the oil-gas separation device is installed in a compressed natural gas filling system, so that the air inlet 1 is connected to the upstream compressed natural gas pipeline, the air outlet 2 is connected to the downstream compressed natural gas pipeline, the oil discharge hole 9 is connected to the exhaust pipe, and a stop valve is arranged on the exhaust pipe. When the stop valve is closed, the compressed natural gas entering the oil-gas separation device passes through the coalescing filter element 8 to achieve oil-gas separation. After separation, the oil droplets fall into the oil accumulation chamber 6 from the oil hole 7 on the partition 4, and the separated compressed natural gas is output from the air outlet 2. When the stop valve is opened, the oil accumulated in the oil accumulation chamber 6 can be discharged. The oil-gas separation device of this structure can ensure that the oil mist mixed in the compressed natural gas is effectively separated, so that the compressed natural gas added to the automobile gas tank does not contain oil mist. Because the partition 4 can also form a certain upward and downward movement under the support of the compression spring 11 when it is under pressure, the pressure of the oil-gas separation chamber 5 and the oil accumulation chamber 6 is balanced, thereby playing a role in protecting the partition 4.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. An oil-gas separation device for a compressed natural gas filling system, Features: The invention comprises a pressure vessel shell (3) provided with an air inlet (1) and an air outlet (2), wherein a partition (4) is arranged in the cavity of the pressure vessel shell (3), and the inner cavity of the pressure vessel shell (3) is divided into an upper cavity and a lower cavity by the partition (4), wherein the upper cavity is an oil-gas separation cavity (5), and the lower cavity is an oil accumulation cavity (6), wherein the partition (4) is supported by a supporting structure arranged in the oil accumulation cavity (6), wherein an oil through hole (7) is arranged on the partition (4) and passes through the partition (4) from top to bottom, wherein a groove (10) is arranged on the upper end surface of the partition (4), wherein the oil through hole (7) is located at the bottom of the groove (10), and wherein the supporting structure at the lower end of the partition (4) is a pressure vessel shell (3). A compression spring (11) is provided, wherein the upper end of the compression spring (11) contacts the partition plate (4) and the lower end contacts the bottom of the pressure vessel shell (3). A coalescing filter element (8) is provided in the oil-gas separation chamber (5). The upper end of the coalescing filter element (8) is fixedly connected to the top of the pressure vessel shell (3) and is connected to the air inlet (1) of the pressure vessel shell (3). The lower end of the coalescing filter element (8) is suspended in the air and does not contact the partition plate (4). An air-passing space is left between the outer wall of the coalescing filter element (8) and the inner wall of the pressure vessel shell (3). The air-passing space is connected to the air outlet (2). An oil drain hole (9) is provided at the bottom of the oil accumulation chamber (6).

2. The oil-gas separation device of the compressed natural gas filling system according to claim 1, Features: The groove (10) is a conical groove, and the conical surface of the conical groove is a guide surface for collecting hydraulic oil.

3. The oil-gas separation device of the compressed natural gas filling system according to claim 1, Features: The supporting structure at the lower end of the partition (4) is a plurality of columns, the upper ends of the columns are in contact with the partition (4), and the lower ends are fixed to the cavity bottom of the pressure vessel shell (3).

4. The oil-gas separation device of the compressed natural gas filling system according to claim 1, Features: An upper end cover (12) is provided at the upper end of the pressure vessel shell (3), the upper end cover (12) is fixedly connected to the pressure vessel shell (3) and is sealed, the air inlet (1) and the air outlet (2) are both provided on the upper end cover (12), the lower end cover (13) is provided at the lower end of the pressure vessel shell (3), the lower end cover (13) is fixedly connected to the pressure vessel shell (3) and is sealed, and the oil drain hole (9) is provided on the lower end cover (13).

5. The oil-gas separation device of the compressed natural gas filling system according to claim 4, Features: The lower end surface of the upper end cover (12) is provided with a mounting groove (14) for fixing the coalescing filter element (8); the air inlet (1) is in communication with the mounting groove (14); an air passing annular groove (15) is provided on the outer periphery of the mounting groove (14); and the air outlet (2) is in communication with the air passing annular groove (15).

6. The oil-gas separation device of the compressed natural gas filling system according to claim 4, Features: The upper end surface of the lower end cover (13) is provided with a positioning hole for mounting a support structure.

7. The oil-gas separation device of the compressed natural gas filling system according to claim 1, Features: The diameter of the oil hole (7) is 5 to 30 mm.

Images