Natural gas condensation separation system and condensation separation method

Abstract

The natural gas condensation and separation system comprises a filter separator, the input end of the filter separator is communicated with a gas collection area through a pipeline, the output end of the filter separator is connected with a first precooling heat exchanger through a pipeline, and the output end of the first precooling heat exchanger is connected with a propane refrigeration device through a pipeline. The propane refrigerating device is connected with a natural gas compressor through a pipeline, the natural gas compressor is connected with a natural gas air cooler through a pipeline, and the natural gas air cooler is communicated with the gas distribution area through a pipeline; the propane refrigerating device is connected with a low-temperature separator through a pipeline, the low-temperature separator is provided with an input end, a liquid outlet end and a gas outlet end, and the liquid outlet end of the low-temperature separator is connected with a low-temperature condensate area three-phase separator through a pipeline; the air outlet end of the low-temperature separator is connected with the first precooling heat exchanger through a pipeline. The invention further discloses a natural gas condensation and separation method, and the natural gas condensation and separation system and the condensation and separation method solve the problem of high cost caused by frequent maintenance or replacement of a heat system due to incrustation blockage.

Description

Technical Field

[0001] The invention belongs to the technical field of natural gas condensation and separation equipment, and in particular relates to a natural gas condensation and separation system, and also relates to a method for condensing and separating natural gas using the system. Background Art

[0002] Existing natural gas processing plants often use propane refrigeration technology as a natural gas de-oiling and dehydration process. In the early stage, traditional evaporative air-cooled condensation was used. Each propane unit was equipped with an air cooler and a fresh water spraying device. Due to the poor water quality in some processing plants, scale frequently blocked the heat exchange system during on-site operation, increasing the frequency and cost of inspection and maintenance. The de-oiling and dehydration device is the core equipment of the natural gas processing plant. Therefore, it is particularly important to design a natural gas condensation separation process technology that reduces investment, energy consumption, and carbon emissions. Summary of the invention

[0003] The purpose of the present invention is to provide a natural gas condensation separation system, which solves the problem of high cost caused by frequent maintenance or replacement of thermal systems due to scale blockage.

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

[0005] The technical solution adopted by the present invention is that the natural gas condensation separation system includes a filter separator, the input end of the filter separator is connected to the gas collection area through a pipeline, the output end of the filter separator is connected to the first precooling heat exchanger through a pipeline, the output end of the first precooling heat exchanger is connected to a propane refrigeration device through a pipeline, the propane refrigeration device is connected to a natural gas compressor through a pipeline, the natural gas compressor is connected to a natural gas air cooler through a pipeline, and the natural gas air cooler is connected to the gas distribution area through a pipeline; the propane refrigeration device is connected to a low-temperature separator through a pipeline, the low-temperature separator is provided with 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 the low-temperature condensate area through a pipeline; the gas outlet end of the low-temperature separator is connected to the first precooling heat exchanger through a pipeline.

[0006] The present invention is also characterized in that:

[0007] The first precooling heat exchanger is provided with two input ends and two output ends.

[0008] The gas outlet end of the low-temperature separator is connected to the second input end of the first precooling heat exchanger through a pipeline.

[0009] The propane refrigeration device includes a second precooling heat exchanger, which is provided with two input ends and two output ends. The first input end of the second precooling heat exchanger is connected to the first output end of the first precooling heat exchanger through a pipeline, the first output end of the second precooling heat exchanger is connected to the input end of the low-temperature separator through a pipeline, the second output end of the second precooling heat exchanger is connected to a propane compressor through a pipeline, the propane compressor is connected to a propane condenser through a pipeline, the propane condenser is connected to a third precooling heat exchanger through a pipeline, the third precooling heat exchanger is provided with two input ends and two output ends, and the second output end of the third precooling heat exchanger is connected to the second input end of the second precooling heat exchanger through a pipeline.

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

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

[0012] The propane condenser is connected to the second input end of the third precooling heat exchanger through a pipeline.

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

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

[0015] Step 2: starting the first precooling heat exchanger to condense the gas output in step 1 by heat exchange;

[0016] Step 3, start the second precooling heat exchanger to condense the gas after heat exchange and condensation in step 2 for secondary heat exchange and output;

[0017] Step 4, start the low-temperature separator to perform low-temperature separation and output the gas not higher than -12°C output in step 3; start the propane compressor, the propane condenser, and the third pre-cooling heat exchanger to allow the propane liquid in the propane refrigeration device to circulate and continue refrigeration;

[0018] Step 5: Start the three-phase separator in the low-temperature condensate area to separate the liquid separated by low temperature in step 4 into three phases; start the natural gas compressor and the natural gas air cooler to compress and condense the gas separated by low temperature in step 4 and transport it to the gas distribution area.

[0019] The beneficial effects of the present invention are:

[0020] The natural gas condensation separation system and condensation separation method provided by the present invention replace the evaporative condensation process of the propane refrigeration device of the conventional processing plant, reduce the exhaust pressure of the compressor by 0.2MPa, and reduce the compressor power by about 20%. The "air cooling" and "water cooling" processes of the refrigeration system are eliminated, and zero water consumption is achieved in the process. There is no need to build new water cooling, air cooling and supporting auxiliary control systems, which reduces investment, does not consume additional fresh water and electricity, reduces carbon emissions, and does not require frequent maintenance or replacement of the thermal system due to scale blockage, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0022] In the figure, 1. gas collection area, 2. filter separator, 3. first precooling heat exchanger, 4. low temperature separator, 5. propane refrigeration device, 6. natural gas compressor, 7. natural gas air cooler, 8. gas distribution area, 9. low temperature condensate area three-phase separator, 10. second precooling heat exchanger, 11. propane compressor, 12. propane condenser, 13. third precooling heat exchanger. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The present invention provides a natural gas condensation separation system, such as Figure 1As shown, it includes a filter separator 2, the input end of the filter separator 2 is connected to the gas collection area 1 through a pipeline, the output end of the filter separator 2 is connected to the first precooling heat exchanger 3 through a pipeline, the first precooling heat exchanger 3 is provided with two input ends and two output ends, the output end of the first precooling heat exchanger 3 is connected to a propane refrigeration device 5 through a pipeline, the propane refrigeration device 5 is connected to a natural gas compressor 6 through a pipeline, the natural gas compressor 6 is connected to a natural gas air cooler 7 through a pipeline, and the natural gas air cooler 7 is connected to the gas distribution area 8 through a pipeline; the propane refrigeration device 5 is connected to a low-temperature separator 4 through a pipeline, the low-temperature separator 4 is provided with 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 area three-phase separator 9 through 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 through a pipeline. The propane refrigeration device 5 includes a second precooling heat exchanger 10, which is provided with 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 pipeline, and 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 pipeline. The second output end of the second precooling heat exchanger 10 is connected to a propane compressor 11 through a pipeline, and the propane compressor 11 is connected to a propane condenser 12 through a pipeline. The propane condenser 12 is connected to a third precooling heat exchanger 13 through a pipeline. The third precooling heat exchanger 13 is provided with two input ends and two output ends, and 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 pipeline. 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 through a pipeline. The natural gas compressor 6 is connected to the first output end of the third precooling heat exchanger 13 through a pipeline. The propane condenser 12 is connected to the second input end of the third precooling heat exchanger 13 through a pipeline.

[0025] The present invention provides a natural gas condensation separation system, and its working principle is as follows: the propane refrigeration device area in the natural gas processing plant receives the natural gas from the gas gathering area, the incoming gas pressure is 2.2-2.5MPa, the temperature is 0℃-3℃ in winter, and 18℃-20℃ in summer. The natural gas first enters the filter separator, and then enters the first precooling heat exchanger to exchange heat with propane liquid. The natural gas is precooled to -7.4℃ in winter and -2.4℃ in summer, and then enters the propane refrigeration device to continue cooling to -16℃ in winter and -12℃ in summer, and then enters the low-temperature separator for separation. After separation, the low-temperature condensate goes to the three-phase separator in the low-temperature condensate area. The low-temperature gas exchanges heat through the first precooling heat exchanger, wherein the temperature of the gas after heat exchange is -6.7℃ in winter and 8.4℃ in summer, and then enters the propane refrigeration device to exchange heat with steam. The gas after heat exchange is 5℃ in winter and 26℃ in summer. After being pressurized by the natural gas compressor, it enters the natural gas air cooler for cooling, and the gas is transported to the gas distribution area.

[0026] After absorbing heat in the second precooling heat exchanger 10, liquid propane turns into propane vapor, and at the same time, the temperature of natural gas is reduced to -16°C / -12°C. The propane vapor enters the propane compressor 11. The pressure of the compressed propane gas rises from 0.24MPa.g to 1.24MPa.g, and the temperature rises from -19.1°C to 76.4°C. The compressed propane gas is condensed into liquid by the propane condenser 12. The propane liquid enters the propane storage tank, and then enters the economizer after the throttle valve is reduced in pressure to separate into gas and liquid phases, and the supplementary gas inlet of the gas propane compressor 11. The liquid enters the second precooling heat exchanger 10 after further throttling and pressure reduction, absorbs the heat of the cooled medium in the second precooling heat exchanger 10, and evaporates into propane vapor, thereby completing the cycle of the entire refrigeration process. The propane in the device is recycled, and no additional heat exchange medium is required.

[0027] Example 1

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

[0029] Example 2

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

[0031] The first precooling heat exchanger 3 is provided with two input ends and two output ends.

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

[0033] Example 3

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

[0035] The first precooling heat exchanger 3 is provided with two input ends and two output ends.

[0036] The gas outlet end of the low temperature separator 4 is connected to the second input end of the first precooling heat exchanger 3 through a pipeline.

[0037] The propane refrigeration device 5 includes a second precooling heat exchanger 10, which is provided with 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 pipeline, and 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 pipeline. The second output end of the second precooling heat exchanger 10 is connected to a propane compressor 11 through a pipeline, and the propane compressor 11 is connected to a propane condenser 12 through a pipeline. The propane condenser 12 is connected to a third precooling heat exchanger 13 through a pipeline. The third precooling heat exchanger 13 is provided with two input ends and two output ends, and 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 pipeline.

[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 through a pipeline.

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

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

[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 pipelines, start the filter separator, filter the natural gas and output it;

[0044] Step 2: starting the first precooling heat exchanger to condense the gas output in step 1 by heat exchange;

[0045] Step 3, start the second precooling heat exchanger to condense the gas after heat exchange and condensation in step 2 for secondary heat exchange and output;

[0046] Step 4, start the low-temperature separator to perform low-temperature separation and output the gas not higher than -12°C output in step 3; start the propane compressor, the propane condenser, and the third pre-cooling heat exchanger to allow the propane liquid in the propane refrigeration device to circulate and continue refrigeration;

[0047] Step 5: Start the three-phase separator in the low-temperature condensate area to separate the liquid separated by low temperature in step 4 into three phases; start the natural gas compressor and the natural gas air cooler to compress and condense the gas separated by low temperature in step 4 and transport it to the gas distribution area.

Claims

1. Natural gas condensation separation system, characterized in that: The invention comprises a filter separator (2), wherein the input end of the filter separator (2) is connected to a gas collection area (1) through a pipeline, the output end of the filter separator (2) is connected to a first precooling heat exchanger (3) through a pipeline, the output end of the first precooling heat exchanger (3) is connected to a propane refrigeration device (5) through a pipeline, the propane refrigeration device (5) is connected to a natural gas compressor (6) through a pipeline, the natural gas compressor (6) is connected to a natural gas air cooler (7) through a pipeline, and the natural gas air cooler (7) is connected to a gas distribution area (8) through a pipeline; the propane refrigeration device (5) is connected to a low-temperature separator (4) through a pipeline, the low-temperature separator (4) is provided with 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 condensation area three-phase separator (9) through a pipeline; the gas outlet end of the low-temperature separator (4) is connected to the first precooling heat exchanger (3) through a pipeline.

2. The natural gas condensation separation system according to claim 1, characterized in that: The first precooling heat exchanger (3) is provided with two input ends and two output ends.

3. The natural gas condensation separation system according to claim 2, characterized in that: The gas outlet end of the low-temperature separator (4) is connected to the second input end of the first precooling heat exchanger (3) through a pipeline.

4. The natural gas condensation separation system according to claim 3, characterized in that: The propane refrigeration device (5) comprises a second precooling heat exchanger (10), the second precooling heat exchanger (10) is provided with 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 pipeline, 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 pipeline, the second output end of the second precooling heat exchanger (10) is connected to a propane compressor (11) through a pipeline, the propane compressor (11) is connected to a propane condenser (12) through a pipeline, the propane condenser (12) is connected to a third precooling heat exchanger (13) through a pipeline, the third precooling heat exchanger (13) is provided with 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 pipeline; 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) through a pipeline.

5. The natural gas condensation separation system according to claim 4, characterized in that: The natural gas compressor (6) is connected to the first output end of the third precooling heat exchanger (13) through a pipeline.

6. The natural gas condensation separation system according to claim 5, characterized in that: The propane condenser (12) is connected to the second input end of the third precooling heat exchanger (13) through a pipeline.

7. A natural gas condensation separation method, characterized in that: Using the natural gas condensation system as claimed in claim 6 comprises the following steps: S1, connecting the gas collection area (1) through a pipeline, starting the filter separator (2), filtering the natural gas and outputting it; S2, starting the first precooling heat exchanger (3) to condense the gas output in S1 by heat exchange; S3, start the second precooling heat exchanger (10), condense the heat exchanged condensed gas in S2 for secondary heat exchange and output; S4, starting the low-temperature separator (4), separating and outputting the gas with a temperature not higher than -12°C outputted in S3 at low temperature; starting the propane compressor (11), the propane condenser (12), and the third precooling heat exchanger (13), so that the propane liquid in the propane refrigeration device (5) circulates and continues to refrigerate; S5, start the low-temperature condensate area three-phase separator (9) to separate the liquid separated by low temperature in S4 into three phases; start the natural gas compressor (6) and the natural gas air cooler (7) to compress and condense the gas separated by low temperature in S4 and transport it to the gas distribution area (8).

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