System for producing CNG (compressed natural gas) by recovering well head gas

Abstract

The utility model discloses a system for producing CNG (compressed natural gas) by recovering wellhead gas, which comprises a pretreatment box, an oil nozzle manifold, a gas-liquid separator, a CNG compressor, a dryer and a gas filling column, the oil nozzle manifold is connected to the gas-liquid separator through a pipeline, a gas outlet pipeline of the gas-liquid separator is connected to the CNG compressor, and the gas filling column is connected to the gas outlet pipeline of the gas-liquid separator. The CNG compression exhaust port is connected to the dryer through a pipeline, the dryer is connected to the gas filling column through a pipeline, the pretreatment box is composed of a box body and a filter screen layer installed in the box body in a separated mode, an inclined plate set is installed in the pretreatment box below the filter screen layer, a gathering hopper is installed at the bottom of the box body, and the gathering hopper is connected to the gas filling column through a pipeline. A sealed sewage discharge barrel is mounted at a hopper opening in the bottom of the gathering hopper, and a sewage discharge cylinder is mounted at one end of the sealed sewage discharge barrel. The device has the beneficial effects that the recycling efficiency is improved, the cleaning difficulty is reduced, the pretreatment structure is good in sealing performance, and high-pressure leakage is not prone to being caused.

Description

Technical Field

[0001] The utility model relates to the field of compressed natural gas recovery and production devices, in particular to a wellhead gas recovery and production CNG system. Background Art

[0002] Compressed natural gas refers to gaseous natural gas that has been compressed to a pressure greater than or equal to 10MPa and not greater than 25MPa. It is natural gas that is pressurized and stored in a container in a gaseous state. A CNG recovery system is usually used for natural gas extraction and recovery at the wellhead. However, a large amount of sewage, liquid and sand will still be entrained in the raw gas at the wellhead. In order to ensure that the natural gas entering the pipeline network does not contain sand and liquid, the system will use filtration, gas-liquid separation, dryer drying and other links. The existing filtration links are mostly achieved through filter valves. The filter cartridge inside the filter valve is prone to accumulation after being used for a period of time and needs to be disassembled and cleaned, which is more troublesome and inefficient. The existing equipment that performs filtering while carrying a sewage discharge structure is mostly auger sewage discharge, which has poor air tightness. Due to the high pressure of the high-pressure mixed fluid at the wellhead, it is easy to cause leakage, which is not convenient for application in CNG recovery systems. Utility Model Content

[0003] The purpose of the utility model is to provide a wellhead gas recovery CNG system in order to solve the above problems.

[0004] The utility model achieves the above-mentioned purpose through the following technical solutions:

[0005] A CNG system for recovering wellhead gas, comprising a pretreatment box, a nozzle manifold, a gas-liquid separator, a CNG compressor, a dryer and a gas filling column, wherein the nozzle manifold pipeline is connected to the gas-liquid separator, the gas outlet pipeline of the gas-liquid separator is connected to the CNG compression, the CNG compression exhaust outlet pipeline is connected to the dryer, and the dryer pipeline is connected to the gas filling column. The pretreatment box is composed of a box body and a filter mesh layer installed inside the box body, an inclined plate group is installed in the pretreatment box below the filter mesh layer, a gathering bucket is installed at the bottom of the box body, a sealed sewage cylinder is installed at the bottom bucket mouth of the gathering bucket, a sewage cylinder is installed at one end of the sealed sewage cylinder, the piston rod end of the sewage cylinder extends into the sealed sewage cylinder and is installed with a sealed sewage plug group, an upper liquid level sensor and a lower liquid level sensor are installed in sequence from top to bottom on the inner box wall of the box body below the inclined plate group, and a drain valve is installed on the box body between the upper liquid level sensor and the lower liquid level sensor.

[0006] Furthermore, the sealed sewage plug group consists of a long plug body and a short plug body, the long plug body and the short plug body are connected together by a plug connecting rod, and a sewage drop hole is provided on the top cylinder wall of the sealed sewage cylinder.

[0007] Furthermore, a filter exhaust pipe is installed on the top of the box body, and the end of the filter exhaust pipe is connected to the nozzle manifold.

[0008] Furthermore, a box air inlet pipe is installed on the side of the box body, and a ground safety valve is installed at the air inlet end of the box air inlet pipe.

[0009] Furthermore, the drain valve is connected to a sewage tank via a drain pipe, and the gas-liquid separator, the CNG compressor, and the dryer are all connected to the sewage tank via pipelines.

[0010] The beneficial effects are as follows: the CNG system for recovering wellhead gas described in the utility model ensures the accumulation of debris in the manifold through the pretreatment structure, discharges debris and sewage without affecting the continuous operation of the system, improves the recovery efficiency, reduces the difficulty of cleaning, and the pretreatment structure has good sealing performance and is not prone to high-pressure leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a system schematic diagram of a CNG production system based on wellhead gas recovery described in the utility model;

[0012] Figure 2 This is a schematic diagram of the interior of a pre-treatment box of a wellhead gas recovery CNG production system described in the utility model;

[0013] Figure 3 It is a schematic diagram of the interior of a sealed sewage cylinder of a wellhead gas recovery CNG production system described in the utility model.

[0014] The following are the descriptions of the reference numerals:

[0015] 1. Pretreatment box; 2. Nozzle manifold; 3. Gas-liquid separator; 4. CNG compressor; 5. Dryer; 6. Gas column; 7. CNG tube bundle vehicle; 8. Sewage tank; 9. Ground safety valve; 10. Sewage cylinder; 11. Box body; 12. Inclined plate group; 13. Box air inlet pipe; 14. Base; 15. Sealed sewage cylinder; 16. Lower liquid level sensor; 17. Upper liquid level sensor; 18. Drain valve; 19. Sewage drop hole; 20. Sealed sewage plug group, 201, long plug body, 202, plug connecting rod, 203, short plug body; 21. Filter mesh layer; 22. Collection bucket. DETAILED DESCRIPTION

[0016] The utility model is further described below in conjunction with the accompanying drawings:

[0017] like Figure 1-Figure 3 As shown, a wellhead gas recovery CNG system is composed of a pretreatment box 1, a nozzle manifold 2, a gas-liquid separator 3, a CNG compressor 4, a dryer 5 and a gas filling column 6;

[0018] The nozzle manifold 2 is connected to the gas-liquid separator 3, the gas outlet pipe of the gas-liquid separator 3 is connected to the CNG compressor 4, the exhaust pipe of the CNG compressor 4 is connected to the dryer 5, and the dryer 5 pipe is connected to the gas filling column 6;

[0019] The pretreatment box 1 is composed of a box body 11 and a filter screen layer 21 installed inside the box body 11. An inclined plate group 12 is installed in the pretreatment box 1 below the filter screen layer 21. The inclined plate group 12 is mainly used for preliminary blocking of sand and gravel. The filter screen layer 21 performs secondary filtering. A gathering bucket 22 is installed at the bottom of the box body 11. A sealed sewage discharge cylinder 15 is installed at the bottom bucket mouth of the gathering bucket 22. The sealed sewage discharge cylinder 15 is arranged horizontally. A sewage discharge cylinder 10 is installed at one end of the sealed sewage discharge cylinder 15. The sewage discharge cylinder 10 adopts an electric cylinder. The piston rod end of the sewage discharge cylinder 10 extends into the sealed sewage discharge cylinder 15 and is installed with a sealed sewage discharge plug group 20. Sewage is discharged through the sealed sewage discharge plug 20;

[0020] An upper liquid level sensor 17 and a lower liquid level sensor 16 are installed on the inner wall of the box body 11 below the inclined plate group 12 from top to bottom. A drain valve 18 is installed on the box body 11 between the upper liquid level sensor 17 and the lower liquid level sensor 16, which mainly discharges the sewage guided by the inclined plate group 12.

[0021] like Figure 1-Figure 3 As shown, the utility model also discloses the following more optimized specific structures:

[0022] The sealed sewage plug group 20 is composed of a long plug body 201 and a short plug body 203, which are connected together by a plug connecting rod 202. The long plug body 201 is arranged on the side close to the sewage cylinder 10, and a sewage hole 19 is provided on the top wall of the sealed sewage cylinder 15. Sand, gravel and sludge fall into the cavity between the long plug body 201 and the short plug body 203 and are discharged.

[0023] A filter exhaust pipe is installed on the top of the box body 11 , and the end of the filter exhaust pipe is connected to the nozzle manifold 2 .

[0024] A box air inlet pipe 13 is installed on the side of the box body 11 , and a ground safety valve 9 is installed at the air inlet end of the box air inlet pipe 13 . The gas at the wellhead first passes through the ground safety valve 9 and then enters the box body 11 .

[0025] The drain valve 18 is connected to the sewage tank 8 through a drain pipe, and the gas-liquid separator 3, the CNG compressor 4, and the dryer 5 are all connected to the sewage tank 8 through pipelines.

[0026] The gas filling column 6 is connected to a CNG tube bundle vehicle 7 through a gas filling pipeline for easy transportation.

[0027] like Figure 1-Figure 3When the wellhead gas recovery CNG system shown is in use, the wellhead mixed gas first returns to the pretreatment box 1 for treatment. During the treatment process, the inclined plate group 12 inside the pretreatment box 1 will block most of the sand and water under the impact of the mixed fluid, and accumulate at the bottom of the pretreatment box 1. Through the internal upper liquid level sensor 17 and the lower liquid level sensor 16, it is convenient to control the water at a certain liquid level. At the same time, the sewage cylinder 10 is started, and the sand and gravel fall into the cavity between the long plug body 201 and the short plug body 203. Then the sealed sewage plug group 20 moves so that the cavity reaches the outside of the sealed sewage cylinder 15 to discharge the debris. At this time, the long plug body 201 completely blocks the sewage hole 19 to make it sealed. After resetting, the long plug body 201 and the short plug body 203 are sealed together, so that the internal air tightness is excellent, and the high-pressure mixed gas is prevented from leaking through the bottom;

[0028] The pretreated gas first enters the nozzle manifold 2 to adjust the pressure to within 6-8MPa, separates free water through the gas-liquid separator, enters the CNG compressor 4 through natural gas, is gradually pressurized to 25Mpa, and then enters the dryer 5 (molecular sieve dehydration) for deep dehydration. After dehydration, it is measured by the gas filling column 6 and loaded into the CNG tube bundle vehicle 7 for transportation.

[0029] Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments. The above-mentioned embodiments and the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements shall fall within the scope of the present invention to be protected.

Claims

1. A CNG production system by recovering wellhead gas, characterized by: It includes a pretreatment box, an oil nozzle manifold, a gas-liquid separator, a CNG compressor, a dryer and a gas filling column, the oil nozzle manifold pipeline is connected to the gas-liquid separator, the gas outlet pipeline of the gas-liquid separator is connected to the CNG compression, the CNG compression exhaust outlet pipeline is connected to the dryer, and the dryer pipeline is connected to the gas filling column. The pretreatment box is composed of a box body and a filter mesh layer installed inside the box body, an inclined plate group is installed in the pretreatment box below the filter mesh layer, a gathering bucket is installed at the bottom of the box body, a sealed sewage cylinder is installed at the bottom bucket mouth of the gathering bucket, a sewage cylinder is installed at one end of the sealed sewage cylinder, the piston rod end of the sewage cylinder extends into the sealed sewage cylinder and is installed with a sealed sewage plug group, an upper liquid level sensor and a lower liquid level sensor are installed on the inner box wall of the box body below the inclined plate group from top to bottom, and a drain valve is installed on the box body between the upper liquid level sensor and the lower liquid level sensor.

2. A CNG production system by wellhead gas recovery according to claim 1, characterized in that: The sealed sewage plug group consists of a long plug body and a short plug body, and the long plug body and the short plug body are connected together through a plug connecting rod. A sewage drop hole is arranged on the top cylinder wall of the sealed sewage cylinder.

3. A CNG production system by wellhead gas recovery according to claim 1, characterized in that: A filter exhaust pipe is installed on the top of the box body, and the end of the filter exhaust pipe is connected to the nozzle manifold.

4. A CNG production system by wellhead gas recovery according to claim 1, characterized in that: A box air inlet pipe is installed on the side of the box body, and a ground safety valve is installed on the air inlet end of the box air inlet pipe.

5. The CNG production system by wellhead gas recovery according to claim 1, characterized in that: The drain valve is connected to a sewage tank via a drain pipe, and the gas-liquid separator, the CNG compressor, and the dryer are all connected to the sewage tank via pipelines.

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