Natural gas condensation separation system and condensation separation method

Abstract

This invention discloses a natural gas condensation separation system, including a filter separator. The input end of the filter separator is connected to a gas collection area via a pipeline. The output end of the filter separator is connected to a first pre-cooling heat exchanger via a pipeline. The output end of the first pre-cooling heat exchanger is connected to a propane refrigeration unit via a pipeline. The propane refrigeration unit is connected to a natural gas compressor via a pipeline. The natural gas compressor is connected to a natural gas air cooler via a pipeline. The natural gas air cooler is connected to a gas distribution area via a pipeline. The propane refrigeration unit is connected to a low-temperature separator via a pipeline. The low-temperature separator has an input end, a liquid outlet end, and a gas outlet end. The liquid outlet end of the low-temperature separator is connected to a three-phase separator in a low-temperature condensate zone via a pipeline. The gas outlet end of the low-temperature separator is connected to the first pre-cooling heat exchanger via a pipeline. This invention also discloses a method for natural gas condensation separation. This natural gas condensation separation system and method solve the problem of high costs caused by frequent maintenance or replacement of the heating system due to scale blockage.

Description

Technical Field

[0001] This invention belongs to the technical field of natural gas condensation and separation equipment, specifically relating to a natural gas condensation and separation system, and also to a method for condensing and separating natural gas using this system. Background Technology

[0002] Existing natural gas processing plants commonly employ propane refrigeration for natural gas deoiling and dehydration. Initially, traditional evaporative air-cooled condensation was used, with each propane unit equipped with an air cooler and fresh water spray system. However, due to poor water quality in some areas, scale buildup frequently clogs the heat exchange system during operation, increasing maintenance frequency and costs. Since the deoiling and dehydration unit is a core component of the natural gas processing plant, designing a natural gas condensation and separation process technology that reduces investment, energy consumption, and carbon emissions is crucial. Summary of the Invention

[0003] The purpose of this invention is to provide a natural gas condensation separation system that solves the problem of high costs caused by frequent maintenance or replacement of the heat system due to scale blockage.

[0004] Another object of the present invention is to provide a method for natural gas condensation and separation.

[0005] The technical solution adopted in this invention is a natural gas condensation separation system, including a filter separator. The input end of the filter separator is connected to a gas collection area via a pipeline. The output end of the filter separator is connected to a first pre-cooling heat exchanger via a pipeline. The output end of the first pre-cooling heat exchanger is connected to a propane refrigeration unit via a pipeline. The propane refrigeration unit is connected to a natural gas compressor via a pipeline. The natural gas compressor is connected to a natural gas air cooler via a pipeline. The natural gas air cooler is connected to a gas distribution area via a pipeline. The propane refrigeration unit is connected to a low-temperature separator via a pipeline. The low-temperature separator has an input end, a liquid outlet end, and a gas outlet end. The liquid outlet end of the low-temperature separator is connected to a three-phase separator in a low-temperature condensate zone via a pipeline. The gas outlet end of the low-temperature separator is connected to the first pre-cooling heat exchanger via a pipeline.

[0006] The invention is further characterized by:

[0007] The first precooling heat exchanger has two input terminals and two output terminals.

[0008] The outlet of the low-temperature separator is connected to the second input of the first precooling heat exchanger via a pipe.

[0009] The propane refrigeration unit includes a second precooling heat exchanger, which has two input terminals and two output terminals. The first input terminal of the second precooling heat exchanger is connected to the first output terminal of the first precooling heat exchanger via a pipe. The first output terminal of the second precooling heat exchanger is connected to the input terminal of a low-temperature separator via a pipe. The second output terminal of the second precooling heat exchanger is connected to a propane compressor via a pipe. The propane compressor is connected to a propane condenser via a pipe. The propane condenser is connected to a third precooling heat exchanger via a pipe. The third precooling heat exchanger has two input terminals and two output terminals. The second output terminal of the third precooling heat exchanger is connected to the second input terminal of the second precooling heat exchanger via a pipe.

[0010] The second output end of the first precooling heat exchanger is connected to the first input end of the third precooling heat exchanger via a pipe.

[0011] The natural gas compressor is connected to the first output end of the third precooling heat exchanger via a pipeline.

[0012] The propane condenser is connected to the second inlet of the third precooling heat exchanger via a pipe.

[0013] Another technical solution adopted in this invention is a natural gas condensation and separation method, comprising the following steps:

[0014] Step 1: Connect the gas collection area through the pipeline, start the filter separator, filter the natural gas and output it;

[0015] Step 2: Start the first precooling heat exchanger to condense the gas output in Step 1.

[0016] Step 3: Start the second precooling heat exchanger to perform secondary heat exchange and condensation of the gas after heat exchange and condensation in Step 2, and then output it.

[0017] Step 4: Start the cryogenic separator to separate and output the gas output in Step 3 at a temperature not higher than -12℃; start the propane compressor, propane condenser, and third pre-cooling heat exchanger to ensure continuous cooling of propane liquid circulation in the propane refrigeration unit.

[0018] Step 5: Start the three-phase separator in the low-temperature condensate zone to perform three-phase separation of the liquid separated at low temperature in Step 4; start the natural gas compressor and natural gas air cooler to compress and condense the gas separated at low temperature in Step 4 and deliver it to the gas distribution zone.

[0019] The beneficial effects of this invention are:

[0020] The natural gas condensation separation system and method provided by this invention replace the evaporative condensation process of conventional propane refrigeration units in processing plants, reducing compressor discharge pressure by 0.2 MPa and compressor power by approximately 20%. It eliminates the need for air-cooling and water-cooling processes in the refrigeration system, achieving zero water consumption in the process. It eliminates the need for new water-cooling, air-cooling, and auxiliary control systems, reducing investment. It also eliminates the need for additional fresh water and electricity consumption, reducing carbon emissions. Furthermore, it avoids frequent maintenance or replacement of the heating system due to scale buildup, thus lowering costs. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the natural gas condensation separation system and condensation separation method of the present invention.

[0022] In the diagram, 1. Gas gathering area, 2. Filter separator, 3. First precooling heat exchanger, 4. Low-temperature separator, 5. Propane refrigeration unit, 6. Natural gas compressor, 7. Natural gas air cooler, 8. Gas distribution area, 9. Low-temperature condensate three-phase separator, 10. Second precooling heat exchanger, 11. Propane compressor, 12. Propane condenser, 13. Third precooling heat exchanger. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] This invention provides a natural gas condensation separation system, such as... Figure 1As shown, the system includes a filter separator 2. The input end of the filter separator 2 is connected to the gas collection area 1 via a pipeline. The output end of the filter separator 2 is connected to a first precooling heat exchanger 3 via a pipeline. The first precooling heat exchanger 3 has two input ends and two output ends. The output end of the first precooling heat exchanger 3 is connected to a propane refrigeration unit 5 via a pipeline. The propane refrigeration unit 5 is connected to a natural gas compressor 6 via a pipeline. The natural gas compressor 6 is connected to a natural gas air cooler 7 via a pipeline. The natural gas air cooler 7 is connected to a gas distribution area 8 via a pipeline. The propane refrigeration unit 5 is connected to a low-temperature separator 4 via a pipeline. The low-temperature separator 4 has an input end, a liquid outlet end, and a gas outlet end. The liquid outlet end of the low-temperature separator 4 is connected to a low-temperature condensate three-phase separator 9 via a pipeline. The gas outlet end of the low-temperature separator 4 is connected to the second input end of the first precooling heat exchanger 3 via a pipeline. The propane refrigeration unit 5 includes a second precooling heat exchanger 10, which has two input terminals and two output terminals. The first input terminal of the second precooling heat exchanger 10 is connected to the first output terminal of the first precooling heat exchanger 3 via a pipe. The first output terminal of the second precooling heat exchanger 10 is connected to the input terminal of the cryogenic separator 4 via a pipe. The second output terminal of the second precooling heat exchanger 10 is connected to a propane compressor 11 via a pipe. The propane compressor 11 is connected to a propane condenser 12 via a pipe. The propane condenser 12 is connected to a third precooling heat exchanger 13 via a pipe. The third precooling heat exchanger 13 has two input terminals and two output terminals. The second output terminal of the third precooling heat exchanger 13 is connected to the second input terminal of the second precooling heat exchanger 10 via a pipe. The second output terminal of the first precooling heat exchanger 3 is connected to the first input terminal of the third precooling heat exchanger 13 via a pipe. A natural gas compressor 6 is connected to the first output terminal of the third precooling heat exchanger 13 via a pipe. The propane condenser 12 is connected to the second input end of the third precooling heat exchanger 13 via a pipe.

[0025] This invention provides a natural gas condensation and separation system. Its working principle is as follows: The propane refrigeration unit area within the natural gas processing plant receives natural gas from the gas gathering area. The incoming gas pressure is 2.2–2.5 MPa, and the temperature is 0–3°C in winter and 18–20°C in summer. The natural gas first enters a filter separator, then enters a first pre-cooling heat exchanger where it exchanges heat with liquid propane, pre-cooling the natural gas to -7.4°C in winter and -2.4°C in summer. It then enters the propane refrigeration unit for further cooling to -16°C in winter and -12°C in summer, before entering a low-temperature separator for separation. The separated low-temperature condensate goes to the three-phase separator in the low-temperature condensate area. The low-temperature gas exchanges heat again through the first pre-cooling heat exchanger, where the temperature after heat exchange is -6.7°C in winter and 8.4°C in summer. It then enters the propane refrigeration unit for heat exchange with steam, where the temperature after heat exchange is 5°C in winter and 26°C in summer. After being pressurized by the natural gas compressor, the gas enters the natural gas air cooler for further cooling before being transported to the gas distribution area.

[0026] Liquid propane absorbs heat in the second precooling heat exchanger 10, turning into propane vapor while simultaneously lowering the natural gas temperature to -16℃ / -12℃. The propane vapor enters the propane compressor 11, where it is compressed, increasing the pressure from 0.24 MPa.g to 1.24 MPa.g and the temperature from -19.1℃ to 76.4℃. The compressed propane gas is then condensed into liquid by the propane condenser 12. The liquid propane enters the propane storage tank, and after being depressurized by a throttling valve, it enters the economizer to separate into two phases: gas and liquid. The liquid enters the makeup gas inlet of the propane compressor 11, while the liquid is further depressurized and enters the second precooling heat exchanger 10. In the second precooling heat exchanger 10, it absorbs heat from the cooled medium and evaporates into propane vapor, thus completing the entire refrigeration cycle. The propane within the unit is recycled, eliminating the need for additional heat exchange medium.

[0027] Example 1

[0028] The natural gas condensation separation system proposed in this embodiment, such as Figure 1 As shown, the system includes a filter separator 2. The input end of the filter separator 2 is connected to the gas collection area 1 via a pipeline. The output end of the filter separator 2 is connected to a first precooling heat exchanger 3 via a pipeline. The output end of the first precooling heat exchanger 3 is connected to a propane refrigeration unit 5 via a pipeline. The propane refrigeration unit 5 is connected to a natural gas compressor 6 via a pipeline. The natural gas compressor 6 is connected to a natural gas air cooler 7 via a pipeline. The natural gas air cooler 7 is connected to a gas distribution area 8 via a pipeline. The propane refrigeration unit 5 is connected to a low-temperature separator 4 via a pipeline. The low-temperature separator 4 has an input end, a liquid outlet end, and a gas outlet end. The liquid outlet end of the low-temperature separator 4 is connected to a low-temperature condensate three-phase separator 9 via a pipeline. The gas outlet end of the low-temperature separator 4 is connected to the first precooling heat exchanger 3 via a pipeline.

[0029] Example 2

[0030] The natural gas condensation separation system proposed in this embodiment, such as Figure 1 As shown, the system includes a filter separator 2. The input end of the filter separator 2 is connected to the gas collection area 1 via a pipeline. The output end of the filter separator 2 is connected to a first precooling heat exchanger 3 via a pipeline. The output end of the first precooling heat exchanger 3 is connected to a propane refrigeration unit 5 via a pipeline. The propane refrigeration unit 5 is connected to a natural gas compressor 6 via a pipeline. The natural gas compressor 6 is connected to a natural gas air cooler 7 via a pipeline. The natural gas air cooler 7 is connected to a gas distribution area 8 via a pipeline. The propane refrigeration unit 5 is connected to a low-temperature separator 4 via a pipeline. The low-temperature separator 4 has an input end, a liquid outlet end, and a gas outlet end. The liquid outlet end of the low-temperature separator 4 is connected to a low-temperature condensate three-phase separator 9 via a pipeline. The gas outlet end of the low-temperature separator 4 is connected to the first precooling heat exchanger 3 via a pipeline.

[0031] The first precooling heat exchanger 3 has two input terminals and two output terminals.

[0032] The outlet of the low-temperature separator 4 is connected to the second input of the first precooling heat exchanger 3 via a pipe.

[0033] Example 3

[0034] The natural gas condensation separation system proposed in this embodiment, such as Figure 1 As shown, the system includes a filter separator 2. The input end of the filter separator 2 is connected to the gas collection area 1 via a pipeline. The output end of the filter separator 2 is connected to a first precooling heat exchanger 3 via a pipeline. The output end of the first precooling heat exchanger 3 is connected to a propane refrigeration unit 5 via a pipeline. The propane refrigeration unit 5 is connected to a natural gas compressor 6 via a pipeline. The natural gas compressor 6 is connected to a natural gas air cooler 7 via a pipeline. The natural gas air cooler 7 is connected to a gas distribution area 8 via a pipeline. The propane refrigeration unit 5 is connected to a low-temperature separator 4 via a pipeline. The low-temperature separator 4 has an input end, a liquid outlet end, and a gas outlet end. The liquid outlet end of the low-temperature separator 4 is connected to a low-temperature condensate three-phase separator 9 via a pipeline. The gas outlet end of the low-temperature separator 4 is connected to the first precooling heat exchanger 3 via a pipeline.

[0035] The first precooling heat exchanger 3 has two input terminals and two output terminals.

[0036] The outlet of the low-temperature separator 4 is connected to the second input of the first precooling heat exchanger 3 via a pipe.

[0037] The propane refrigeration unit 5 includes a second precooling heat exchanger 10, which has two input ends and two output ends. The first input end of the second precooling heat exchanger 10 is connected to the first output end of the first precooling heat exchanger 3 through a pipe. The first output end of the second precooling heat exchanger 10 is connected to the input end of the low-temperature separator 4 through a pipe. The second output end of the second precooling heat exchanger 10 is connected to a propane compressor 11 through a pipe. The propane compressor 11 is connected to a propane condenser 12 through a pipe. The propane condenser 12 is connected to a third precooling heat exchanger 13 through a pipe. The third precooling heat exchanger 13 has two input ends and two output ends. The second output end of the third precooling heat exchanger 13 is connected to the second input end of the second precooling heat exchanger 10 through a pipe.

[0038] The second output end of the first precooling heat exchanger 3 is connected to the first input end of the third precooling heat exchanger 13 via a pipe.

[0039] The natural gas compressor 6 is connected to the first output end of the third precooling heat exchanger 13 via a pipeline.

[0040] The propane condenser 12 is connected to the second input end of the third precooling heat exchanger 13 via a pipe.

[0041] Example 4

[0042] The natural gas condensation separation method proposed in this embodiment includes the following steps:

[0043] Step 1: Connect the gas collection area through the pipeline, start the filter separator, filter the natural gas and output it;

[0044] Step 2: Start the first precooling heat exchanger to condense the gas output in Step 1.

[0045] Step 3: Start the second precooling heat exchanger to perform secondary heat exchange and condensation of the gas after heat exchange and condensation in Step 2, and then output it.

[0046] Step 4: Start the cryogenic separator to separate and output the gas output in Step 3 at a temperature not higher than -12℃; start the propane compressor, propane condenser, and third pre-cooling heat exchanger to ensure continuous cooling of propane liquid circulation in the propane refrigeration unit.

[0047] Step 5: Start the three-phase separator in the low-temperature condensate zone to perform three-phase separation of the liquid separated at low temperature in Step 4; start the natural gas compressor and natural gas air cooler to compress and condense the gas separated at low temperature in Step 4 and deliver it to the gas distribution zone.

Claims

1. A natural gas condensate separation system characterized by, The natural gas condensing separation system comprises a filtering separator (2), a first pre-cooling heat exchanger (3), a propane refrigeration device (5), a natural gas compressor (6), a natural gas air cooler (7), a low-temperature separator (4), a low-temperature condensate zone three-phase separator (9), a second pre-cooling heat exchanger (10), a propane compressor (11), a propane condenser (12) and a third pre-cooling heat exchanger (13). The first pre-cooling heat exchanger (3) is provided with two input ends and two output ends. The low-temperature separator (4) is connected with the second input end of the first pre-cooling heat exchanger (3) through a pipeline. The propane refrigeration device (5) comprises the second pre-cooling heat exchanger (10), which is provided with two input ends and two output ends. The second output end of the first pre-cooling heat exchanger (3) is connected with the first input end of the third pre-cooling heat exchanger (13) through a pipeline. The natural gas compressor (6) is connected with the first output end of the third pre-cooling heat exchanger (13) through a pipeline. The propane condenser (12) is connected with the second input end of the third pre-cooling heat exchanger (13) through a pipeline.

2. A natural gas condensate separation process characterised by, The natural gas condensing separation system comprises the following steps: S1, connecting the gas collection zone (1) through a pipeline, starting the filtering separator (2), filtering the natural gas and outputting; S2, starting the first pre-cooling heat exchanger (3), performing heat exchange condensation on the gas output in S1; S3, starting the second pre-cooling heat exchanger (10), performing secondary heat exchange condensation on the heat exchange condensation gas in S2 and outputting; S4, starting the low-temperature separator (4), performing low-temperature separation on the gas not higher than -12 DEG C output in S3 and outputting; starting the propane compressor (11), the propane condenser (12) and the third pre-cooling heat exchanger (13) to make the propane liquid in the propane refrigeration device (5) circulate continuously. S5, start the low-temperature condensate zone three-phase separator (9) to separate the liquid separated in S4; start the natural gas compressor (6) and the natural gas air cooler (7) to compress and condense the gas separated in S4, and deliver the compressed and condensed gas to the gas distribution zone (8).

Images