Coal bed gas low-temperature dehydration system

Abstract

The utility model provides a coal bed gas low-temperature dehydration system, which belongs to the technical field of coal bed gas dehydration, and comprises a booster station inlet manifold, a booster station compressor, a refrigeration dryer and a booster station outlet manifold, the refrigeration dryer comprises a refrigeration dryer compressor, an oil separator, a condenser, an expansion valve, an evaporator, a gas-liquid separator and a preheater. The system can reduce the dew point of the coal-bed gas water, the dew point of the coal-bed gas water entering the gathering and transportation pipeline is 3-5 DEG C, the amount of water entering the gathering and transportation pipeline is reduced from the source, and safe and stable operation of the gathering and transportation pipeline is protected.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal bed gas dehydration, and specifically discloses a coal bed gas low temperature dehydration system. Background Art

[0002] Currently, most first-stage booster station compressors use screw compressors, which use air cooling to cool the compressed coalbed methane. The outlet coalbed methane temperature is 40-60°. The water in the high-temperature coalbed methane in the station exists in gaseous form. As the pipeline is transported, the coalbed methane temperature gradually decreases, and the saturated water in the coalbed methane precipitates in the form of condensed water and gathers in the low-lying areas of the pipeline. There is a large amount of liquid condensed water in the gathering and transportation pipeline, which increases the pressure difference between the upstream and downstream of the pipeline. The liquid water corrodes the inner wall of the pipeline, and the liquid water rubs back and forth in the low-lying areas, just like sandpaper grinding the inner wall of the pipeline, posing a great threat to the safe and stable operation of the pipeline. Utility Model Content

[0003] In order to solve the problem of condensed water in the gathering and transportation pipeline and improve the safe and stable operation of the pipeline, and reduce the amount of water entering the gathering and transportation pipeline from the source, the utility model provides a coalbed methane low-temperature dehydration system, which dehydrates and cools the outlet coalbed methane of the first-level booster station to reduce the water dew point of the outlet coalbed methane.

[0004] The utility model provides a coal bed methane low temperature dehydration system, comprising a booster station inlet manifold, a booster station compressor, a cold dryer, and a booster station outlet manifold; the cold dryer comprises a cold dryer compressor, an oil separator, a condenser, an expansion valve, an evaporator, a gas-liquid separator, and a preheater; the condensing agent outlet of the cold dryer compressor is connected to the condensing agent inlet of the oil separator, the condensing agent outlet of the oil separator is connected to the condensing agent inlet of the condenser, the condensing agent outlet of the condenser is connected to the inlet of the expansion valve, the outlet of the expansion valve is connected to the condensing agent inlet of the evaporator, the condensing agent outlet of the evaporator is connected to the condensing agent outlet of the cold dryer compressor, and the condensing agent outlet of the evaporator is connected to the condensing agent outlet of the cold dryer compressor. Import connection; the oil outlet of the cold dryer compressor is connected to the oil inlet of the oil separator, the oil return port of the oil separator is connected to the lubricating oil interface of the cold dryer compressor; the booster station inlet manifold is connected to the coalbed methane inlet of the booster station compressor, the coalbed methane outlet of the booster station compressor is connected to the coalbed methane inlet Ⅰ of the preheater, the coalbed methane outlet Ⅰ of the preheater is connected to the coalbed methane inlet of the evaporator, the coalbed methane outlet of the evaporator is connected to the coalbed methane inlet of the gas-liquid separator, the coalbed methane outlet of the gas-liquid separator is connected to the coalbed methane inlet Ⅱ of the preheater, and the coalbed methane outlet Ⅱ of the preheater is connected to the booster station outlet manifold.

[0005] In the above-mentioned coalbed methane low-temperature dehydration system, the gas-liquid separator also includes a drain outlet, and a drain valve is installed on the drain outlet.

[0006] In the above-mentioned coalbed methane low-temperature dehydration system, the condenser adopts an air-cooled condenser or a water-cooled condenser.

[0007] The above-mentioned coalbed methane low-temperature dehydration system also includes a filter, which is installed between the booster station inlet manifold and the booster station compressor.

[0008] Compared with the prior art, the utility model has the following beneficial effects:

[0009] 1. It can reduce the dew point of coalbed methane water. The dew point of coalbed methane water entering the gathering and transportation pipeline is 3-5℃, which reduces the amount of water entering the gathering and transportation pipeline from the source and protects the safe and stable operation of the gathering and transportation pipeline;

[0010] 2. Reduce the pressure difference between upstream and downstream of the gathering and transportation pipeline, and at the same time reduce the exhaust pressure and operating load of the screw compressor, saving energy and reducing consumption;

[0011] 3. It can greatly alleviate the operating load of the dehydration equipment in the secondary booster station, ensure the dehydration effect of the secondary booster station, and further improve the quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 This is a schematic diagram of a coalbed methane low-temperature dehydration system;

[0014] Figure 2 Schematic diagram of the cold dryer.

[0015] In the figure: 1-boosting station inlet manifold; 2-filter; 3-boosting station compressor; 4-refrigerated dryer; 5-boosting station outlet manifold;

[0016] 4.1-dryer compressor; 4.2-oil separator; 4.3-condenser; 4.4-expansion valve; 4.5-evaporator; 4.6-gas-liquid separator; 4.7-preheater. DETAILED DESCRIPTION

[0017] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] The present embodiment provides a coalbed methane low-temperature dehydration system, comprising a booster station inlet manifold 1, a filter 2, a booster station compressor 3, a cold dryer 4, and a booster station outlet manifold 5.

[0019] The cold dryer 4 comprises a cold dryer compressor 4.1, an oil separator 4.2, a condenser 4.3, an expansion valve 4.4, an evaporator 4.5, a gas-liquid separator 4.6 and a preheater 4.7; the condensing agent outlet of the cold dryer compressor 4.1 is connected to the condensing agent inlet of the oil separator 4.2, the condensing agent outlet of the oil separator 4.2 is connected to the condensing agent inlet of the condenser 4.3, the condensing agent outlet of the condenser 4.3 is connected to the inlet of the expansion valve 4.4, the outlet of the expansion valve 4.4 is connected to the condensing agent inlet of the evaporator 4.5, and the condensing agent outlet of the evaporator 4.5 is connected to the condensing agent inlet of the cold dryer compressor 4.1, so as to realize the circulation of the condensing agent; the oil outlet of the cold dryer compressor 4.1 is connected to the oil inlet of the oil separator 4.2, the oil return port of the oil separator 4.2 is connected to the lubricating oil interface of the cold dryer compressor 4.1, and the separated oil is returned to the lubricating oil system of the cold dryer compressor 4.1 for reuse.

[0020] The inlet manifold 1 of the boosting station is connected to the coalbed methane inlet of the filter 2, the coalbed methane outlet of the filter 2 is connected to the coalbed methane inlet of the compressor 3 of the boosting station, the coalbed methane outlet of the compressor 3 of the boosting station is connected to the coalbed methane inlet I of the preheater 4.7, the coalbed methane outlet I of the preheater 4.7 is connected to the coalbed methane inlet of the evaporator 4.5, the coalbed methane outlet of the evaporator 4.5 is connected to the coalbed methane inlet of the gas-liquid separator 4.6, the coalbed methane outlet of the gas-liquid separator 4.6 is connected to the coalbed methane inlet II of the preheater 4.7, and the coalbed methane outlet II of the preheater 4.7 is connected to the outlet manifold 5 of the boosting station.

[0021] In the above-mentioned coalbed methane low-temperature dehydration system, the gas-liquid separator 4.6 also includes a drain outlet, and a drain valve is installed on the drain outlet.

[0022] In the above-mentioned coalbed methane low-temperature dehydration system, the condenser 4.3 adopts an air-cooled condenser or a water-cooled condenser.

[0023] The compressor 3 of the boosting station is usually of screw type or reciprocating type, and the first-stage boosting station is currently all of screw type.

[0024] The processing flow of the above-mentioned coalbed methane low temperature dehydration system is as follows:

[0025] (1) Pretreatment of coalbed methane before entering the station: Preliminary treatment of coalbed methane before entering the station, such as dust removal and oil removal, to prevent subsequent processes from being interfered by impurities and improve the effect of the cold dryer 4;

[0026] (2) The high-temperature coal-bed gas compressed by the booster station compressor 3 and filtered by the filter 2 enters the coal-bed gas inlet Ⅰ of the preheater 4.7, exchanges heat with the low-temperature coal-bed gas provided by the gas-liquid separator 4.6, and is pre-cooled. Then, the pre-cooled medium-temperature coal-bed gas enters the evaporator 4.5 from the coal-bed gas outlet Ⅰ;

[0027] (3) In the evaporator 4.5, the condensing agent absorbs the heat of the medium-temperature coal-bed gas, the temperature of the medium-temperature coal-bed gas decreases, and the gaseous water adsorbed in the coal-bed gas condenses into liquid water;

[0028] (4) The low-temperature coal-bed methane and the condensed liquid water enter the gas-liquid separator 4.6, and the liquid water is separated from the low-temperature coal-bed methane by gravity separation or centrifugal separation. The liquid water is collected or discharged from the drain valve, and the low-temperature coal-bed methane enters the coal-bed methane inlet II of the preheater 4.7 from the coal-bed methane outlet;

[0029] (5) In the preheater 4.7, the low-temperature coal-bed gas exchanges heat with the high-temperature coal-bed gas, and the low-temperature coal-bed gas absorbs the heat of the high-temperature coal-bed gas to recover its temperature, and enters the booster station outlet manifold 5 from the coal-bed gas outlet II of the preheater 4.7;

[0030] (6) Outbound coalbed methane transportation: The coalbed methane that has been fully processed is transported to downstream processes or users through pipelines.

[0031] After the coalbed methane completes the low-temperature dehydration process, the gaseous water adsorbed in the coalbed methane is cooled, condensed and discharged. The dew point of the coalbed methane water entering the gathering and transportation pipeline is 3-5°C, and no condensed water will be precipitated in the gathering and transportation pipeline.

[0032] The above is only a preferred embodiment of the utility model, and does not limit the utility model in other forms. Any person skilled in the art can use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the utility model without departing from the technical solution of the utility model still belongs to the protection scope of the technical solution of the utility model.

Claims

1. A coalbed methane low-temperature dehydration system, comprising a booster station inlet manifold, a booster station compressor, a cold dryer, and a booster station outlet manifold; The cold dryer comprises a cold dryer compressor, an oil separator, a condenser, an expansion valve, and an evaporator; The condensing agent outlet of the cold dryer compressor is connected to the condensing agent inlet of the oil separator, the condensing agent outlet of the oil separator is connected to the condensing agent inlet of the condenser, the condensing agent outlet of the condenser is connected to the inlet of the expansion valve, the outlet of the expansion valve is connected to the condensing agent inlet of the evaporator, and the condensing agent outlet of the evaporator is connected to the condensing agent inlet of the cold dryer compressor; The oil outlet of the cold dryer compressor is connected to the oil inlet of the oil separator, and the oil return port of the oil separator is connected to the lubricating oil interface of the cold dryer compressor; It is characterized in that The cold dryer also includes a gas-liquid separator and a preheater; The inlet manifold of the boosting station is connected to the coalbed methane inlet of the boosting station compressor, the coalbed methane outlet of the boosting station compressor is connected to the coalbed methane inlet I of the preheater, the coalbed methane outlet I of the preheater is connected to the coalbed methane inlet of the evaporator, the coalbed methane outlet of the evaporator is connected to the coalbed methane inlet of the gas-liquid separator, the coalbed methane outlet of the gas-liquid separator is connected to the coalbed methane inlet II of the preheater, and the coalbed methane outlet II of the preheater is connected to the outlet manifold of the boosting station.

2. The coal bed methane low temperature dehydration system according to claim 1, characterized in that: The gas-liquid separator also includes a drain outlet, on which a drain valve is installed.

3. The coal bed methane low temperature dehydration system according to claim 1, characterized in that: The condenser adopts an air-cooled condenser or a water-cooled condenser.

4. The coal bed methane low temperature dehydration system according to claim 1, characterized in that: It also includes a filter, which is installed between the booster station inlet manifold and the booster station compressor.

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