CN107460015A - A kind of deep natural gas dewatering system device and dewatering - Google Patents

Abstract

The invention discloses a natural gas deep dehydration system device, which is characterized in that it includes a filter separator, a first supergravity machine, a condenser, a lean/rich liquid heat exchanger, a booster pump, a buffer tank, a reboiler, a second Two super gravity machine, flash tank, transfer pump, first stop valve, second stop valve, third stop valve, fourth stop valve, fifth stop valve, pressure reducing valve, flow meter, vacuum pump, gas-liquid separator and a three-way valve; the present invention also discloses a dehydration method; the device of the present invention can improve the purity of triethylene glycol lean liquid to 99.99wt% after regeneration, and use the triethylene glycol lean liquid as an absorbent to absorb The dew point of the natural gas outlet water treated by water absorption in the system is reduced to below -35°C, preferably below -45°C; it solves the problem of low dehydration depth of natural gas in the absorption system caused by the low purity of triethylene glycol, and meets the requirements of low water Dehydration treatment requirements for dew point natural gas.

Description

A natural gas deep dehydration system device and dehydration method

technical field

The invention relates to the technical field of oil and natural gas treatment and processing, in particular to a natural gas deep dehydration system device and a dehydration method.

Background technique

Natural gas is a clean fuel with low combustion pollution and high calorific value, and it plays an increasingly important role in the modern energy structure. However, natural gas contains a large amount of water vapor when it is extracted from oil and gas fields or after desulfurization treatment. The water in natural gas will cause some problems in the process of natural gas processing and transmission. Saturated water vapor in natural gas will condense and form solid hydrate at a specific temperature and pressure, and the low temperature and high pressure environment will aggravate this phenomenon. Solid crystalline hydrate will cause blockage of pipelines, instruments and valves, giving The safe delivery of natural gas poses potential hazards. In addition, there are acid gases in natural gas, such as hydrogen sulfide and carbon dioxide, which will form acid substances when combined with water, which will cause corrosion to pipelines and equipment.

At present, the commonly used natural gas dehydration methods include solid adsorption method, solvent absorption method, freeze separation method and so on. Among the three methods, the solid adsorption method has the highest dehydration depth, but its basic investment is high, and the energy consumption of adsorbent regeneration is high, so its application range is limited. The solvent absorption method is the preferred method in industrial applications because of its simple operation and large processing capacity. In this method, triethylene glycol is widely used as an absorbent. TEG dehydration system consists of two parts: natural gas dehydration system and TEG regeneration system. Traditional triethylene glycol dehydration mainly uses packed towers as dehydration devices, and rectification towers as regeneration devices, which have the following disadvantages: 1. The size of the tower equipment is large, the mass transfer efficiency is low, the investment is high, and it is difficult to pry; 2. Triethylene glycol The alcohol regeneration temperature is high, and the system consumes a lot of energy.

Hypergravity technology is an emerging technology for process intensification that can enhance mass transfer. The super-gravity technology uses the centrifugal force generated by the high-speed rotating rotor to crush the liquid into extremely small liquid films and droplets, and the update speed of the phase interface is accelerated, which greatly enhances the mass transfer process. It has short residence time, simple operation, and high vapor-liquid mass transfer efficiency. The advantages of high height and small equipment size.

Chinese invention patent CN201410490633 reports a high-gravity TEG natural gas dehydration system and its process. This process uses a high-gravity rotating packed bed as an absorption and regeneration device to improve the mass transfer efficiency of the TEG-natural gas dehydration system. The natural gas dehydration system is simplified and the size of the dehydration equipment is reduced. This system and process can regenerate the triethylene glycol lean solution to a minimum purity of 99.0%. Using this pure triethylene glycol solution for natural gas dehydration, the water dew point temperature can be reduced to about -18°C, which can reach natural gas at normal ambient temperatures. The requirements of transportation meet the needs of preliminary dehydration treatment of natural gas in some processes.

GB50251-2003 puts forward clear requirements on the water dew point of natural gas transported by pipelines: the water dew point should be 5°C lower than the minimum ambient temperature under the transportation conditions. This puts forward higher requirements for natural gas transportation in cold regions (such as regions where the extreme temperature in winter is lower than -25°C). Therefore, in order to obtain natural gas with low water dew point to ensure the safe transportation of natural gas in cold regions, deep dehydration treatment of natural gas is necessary. Liquefied natural gas requires the dew point of water to reach -100°C before liquefaction, which requires the use of solid adsorption method for deep dehydration treatment, and this method requires a large basic investment and high energy consumption for adsorbent regeneration, so it is generally used in the actual industrial production of liquefied natural gas Sectional dehydration, first use triethylene glycol to deeply dehydrate natural gas, remove most of the water in the natural gas, reduce the water dew point to below -35°C, and then use solid adsorption to remove the low content of water to reach The required low dew point temperature. To sum up, in order to obtain natural gas with a low water dew point, it is necessary to develop a new process-intensive natural gas deep dehydration treatment system and process.

However, using the system and process proposed in the above patent CN201410490633 can only reduce the water dew point of natural gas to -18°C, which obviously cannot meet the dehydration treatment requirements of natural gas with low water dew point. This is because the water dew point temperature that can be achieved after dehydration of natural gas in this system is essentially determined by the purity of the regenerated triethylene glycol lean liquid recycled in the system. The lower the natural gas water dew point. In the system and process described in the above-mentioned patent, the triethylene glycol-rich liquid from the absorption system obtains heat through the lean/rich liquid heat exchanger and then heats up in the regenerative supergravity machine. On the one hand, due to the heat transfer efficiency of the heat exchanger Limitation, insufficient temperature rise, on the other hand, due to the chemical limitation of the vapor-liquid balance in the regeneration supergravity machine, there is a bottleneck in the regeneration effect. Therefore, generally only about 99.0% of triethylene glycol lean liquid can be obtained in the regeneration system by using the process in this invention patent, and the limit water dew point temperature of natural gas that uses this lean liquid for absorption and dehydration treatment can only reach about -18°C. It cannot meet the requirements of deep dehydration treatment of natural gas with low water dew point.

Contents of the invention

The first technical problem to be solved by the present invention is to provide a natural gas deep dehydration system device; the device can improve the purity of the triethylene glycol lean liquid to 99.99wt% after regeneration, and use the triethylene glycol lean liquid as an absorbent, It can reduce the dew point of the natural gas outlet water treated by water absorption in the absorption system to below -35°C, preferably below -45°C; thus solving the problem of low dehydration depth of natural gas in the absorption system caused by the low purity of triethylene glycol , to meet the dehydration treatment requirements of natural gas with low water dew point. At the same time, both the dehydration of natural gas and the regeneration of triethylene glycol use high-gravity reactors. By strengthening the gas-liquid mass transfer, the equipment size and investment are reduced, so that it can meet the natural gas processing requirements of space-constrained occasions such as offshore platforms.

The second technical problem to be solved by the present invention is to provide the above-mentioned natural gas deep dehydration system device and dehydration method.

In order to solve the above-mentioned first technical problem, the invention adopts the following technical solutions:

The present invention is a deep dehydration system device for natural gas, comprising a filter separator, a first supergravity machine, a condenser, a lean/rich liquid heat exchanger, a booster pump, a buffer tank, a reboiler, a second supergravity machine, a flash Steam tank, delivery pump, first stop valve, second stop valve, third stop valve, fourth stop valve, fifth stop valve, pressure reducing valve, flow meter, vacuum pump, gas-liquid separator and three-way valve;

The outlet of the filter separator is connected to the gas phase inlet of the first supergravity machine, the gas phase outlet of the first supergravity machine is connected to the first stop valve inlet, and the first stop valve outlet leads to the downstream section; the first A third cut-off valve, a pressure reducing valve and a flowmeter are connected in series on the regenerative gas branch after the outlet of the cut-off valve, and the outlet of the flowmeter is connected to the gas phase inlet of the reboiler;

The gas phase outlet of the reboiler is connected with the gas phase inlet of the second supergravity machine, the gas phase outlet of the second supergravity machine, the gas outlet of the buffer tank and the vacuum pump inlet are connected with a three-way valve, and the vacuum pump Provide a negative pressure environment for the second supergravity machine, reboiler, and buffer tank; the liquid phase outlet of the reboiler leads to the buffer tank inlet through the second shut-off valve;

The outlet of the vacuum pump is connected to the gas phase inlet of the gas-liquid separator, and the gas phase outlet of the gas-liquid separator leads to the reboiler as its heating fuel;

The liquid phase outlet of the first supergravity machine is connected to the rich liquid inlet of the lean/rich liquid heat exchanger, and the rich liquid outlet of the lean/rich liquid heat exchanger is connected to the flash tank inlet, and the flash tank The gas phase outlet of the flash tank also leads to the reboiler as heating fuel, the liquid outlet of the flash tank is connected to the inlet of the transfer pump, and the gas phase outlet of the flash tank is connected to the gas-liquid separator; the outlet of the transfer pump is connected to the The liquid phase inlet of the second supergravity machine is connected, the liquid phase outlet of the second supergravity machine is connected with the liquid phase inlet of the reboiler, and the liquid phase outlet of the reboiler is connected with the buffer tank inlet through the second stop valve , the liquid phase outlet of the buffer tank is connected to the inlet of the booster pump, the outlet of the booster pump is connected to the lean liquid inlet of the lean/rich liquid heat exchanger, and the lean liquid outlet of the lean/rich liquid heat exchanger is connected to The inlet of the condenser is connected, and the outlet of the condenser is connected with the liquid phase inlet of the first supergravity machine to realize the circulation of triethylene glycol.

As a further improvement of the technical solution, a fourth cut-off valve is also provided on the pipeline connecting the vacuum pump and the three-way valve.

As a further improvement of the technical solution, the pipeline connecting the gas phase outlet of the flash tank to the gas-liquid separator is connected to a three-way valve through a branch pipeline, and a fifth stop valve is provided on the branch pipeline.

In order to solve the above-mentioned second technical problem, the present invention utilizes the dehydration method of the above-mentioned natural gas deep dehydration system device, comprising the following steps:

1) The natural gas raw material gas with a pressure of 2-10MPa enters the filter separator to remove free liquid water and solid impurities, and then is discharged from the outlet of the filter separator;

2), the natural gas raw material gas discharged in step 1) enters the first supergravity machine, and dehydrates in the first supergravity machine with triethylene glycol poor liquid in countercurrent contact, and the dehydrated natural gas is discharged from the first supergravity machine, and a part is used as a product Gas, another small part is taken as the regeneration gas, and the regeneration gas enters the reboiler after being decompressed by the pressure reducing valve;

3), the triethylene glycol rich liquid after water absorption in step 2) discharges the first supergravity machine from the liquid outlet of the first supergravity machine, and enters the flash tank after heat exchange with the triethylene glycol poor liquid;

4), the regenerated gas that enters from the bottom of the reboiler in step 2) is discharged from the outlet at the top of the reboiler after being contacted with triethylene glycol in the reboiler, and enters the second supergravity machine;

5), the triethylene glycol in step 3) is pumped into the second supergravity machine after being flashed by the flash tank, and the gas phase outlet of the second supergravity machine, the gas outlet of the buffer tank, and the vacuum pump are connected by a three-way valve, When opening the 4th shut-off valve and closing the 5th shut-off valve, the vacuum pump provides a single and stable negative pressure environment for the second supergravity machine, reboiler and surge tank; step 3) pumps into the third of the second supergravity machine The regeneration gas discharged from the reboiler in the glycol-rich solution and step 4) is countercurrently contacted and regenerated in a negative pressure environment; the regenerated triethylene glycol lean solution is discharged from the liquid phase outlet of the second supergravity machine; the regeneration gas is discharged from the second The gas phase outlet of the supergravity machine is discharged;

6), in step 5), the regeneration gas discharged from the gas phase outlet of the second supergravity machine is discharged by the vacuum pump and enters the gas-liquid separator, and can be used as a heating fuel for the reboiler after condensing and removing free liquid water;

7), in step 5), the triethylene glycol lean liquid flowing out from the second supergravity machine enters the reboiler, and after being contacted with the regeneration gas for the second time and fully replenishing heat, it is discharged from the liquid phase outlet of the reboiler;

8), step 7) the triethylene glycol barren solution discharged from the liquid phase outlet of the reboiler enters the buffer tank, forming a stable liquid level in the buffer tank;

9), the triethylene glycol poor liquid in the buffer tank in step 8) is transported to the lean/rich liquid heat exchanger by the booster pump; in the lean/rich liquid heat exchanger, it is exchanged with the triethylene glycol rich liquid in step 3) After being condensed by the condenser, it enters the first supergravity machine again to realize the circulation of triethylene glycol.

As a further improvement of the technical solution, in step 2), the volume ratio of regeneration gas consumption to product gas is 1:1000-1:10000.

As a further improvement of the technical solution, in step 2), the volume ratio of the triethylene glycol lean liquid to the natural gas raw material gas is 1:5000-1:50000.

As a further improvement of the technical solution, the supergravity level of the first supergravity machine in step 2) is 20-1000, and the supergravity level of the second supergravity machine in step 5) is 20-1000.

Through the above-mentioned dehydration process of the present invention, the purity of triethylene glycol lean liquid in step 2) can reach 99.99wt%, and the dehydration treatment of natural gas can be carried out by using triethylene glycol of this purity, and the dew point of the natural gas outlet can reach below -35°C, and the minimum can be reduced to Below -45°C.

As a further improvement of the technical solution, the vacuum degree of the second supergravity machine, reboiler and buffer tank in step 5) is 50-90kPa.

As a further improvement of the technical solution, in step 7), the temperature of the reboiler is 160-204°C.

As a further improvement of the technical solution, the temperature of the condenser in step 9) is 15-40°C.

Any range recited in the present invention includes the endpoints and any value between the endpoints and any sub-range formed by the endpoints or any value between the endpoints.

Unless otherwise specified, each raw material in the present invention can be purchased commercially, and the equipment used in the present invention can be carried out by using conventional equipment in the field or referring to the prior art in the field.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The dehydration depth is high. The system and process proposed by the present invention, in the triethylene glycol regeneration system, develops a new regeneration process, through the introduction of a reboiler, it can fully supplement heat for the rich liquid regeneration process, and promote its full regeneration; through the introduction of regeneration gas, strengthen The turbulence of the liquid phase in the regenerative supergravity machine reduces the water pressure in the gas phase; the vacuum pump creates a negative pressure environment to promote the transfer of water from the liquid phase to the gas phase, breaking through the limitations of the normal pressure thermal regeneration method in the original process. The purity of the regenerated triethylene glycol lean liquid can be increased to 99.99wt% through the system and process proposed by the present invention, and the use of the triethylene glycol lean liquid as an absorbent can reduce the dew point of the natural gas outlet water treated by water absorption in the absorption system to below -45°C.

(2) The scope of application is wide. The system of the present invention has two kinds of TEG regeneration methods: negative pressure enhanced regeneration and regeneration gas enhanced regeneration. The system can select a suitable TEG regeneration method according to the actual situation. If the requirements for natural gas dehydration are not high, a separate method can be used. Use one of these methods to keep costs down. If the dehydration treatment requirements are high, two methods can be used at the same time to meet the natural gas dehydration process with different requirements.

(3) Intensive process. The regeneration gas introduced in the present invention comes from the natural gas processed by the system itself, without the addition of external media. In addition, this part of the regeneration gas can not only be used as a working medium, but also in the triethylene glycol regeneration system by enhancing liquid phase turbulence and reducing water vapor partial pressure. The method strengthens regeneration, improves the purity of triethylene glycol lean liquid, and can be used as heating fuel for the reboiler in the system after simple treatment in the discharge regeneration system, so as to realize the system's own heat extraction and full utilization of energy, and the process is intensive.

(4) Both the natural gas dehydration system and the triethylene glycol regeneration system in the system of the present invention utilize supergravity reactors. Therefore, this system has the advantages of supergravity technology: greatly increasing the gas-liquid contact area, improving the gas-liquid mass transfer efficiency, simple operation, small equipment size, easy to start and stop, suitable for space-constrained areas, such as offshore platforms and offshore Natural gas exploration operation ship, etc.

Description of drawings

Below in conjunction with accompanying drawing, specific embodiment of the present invention is described in further detail

Fig. 1 is the structural schematic diagram of the natural gas deep dehydration system device of the present invention;

Numbers labeled in Figure 1:

1-filter separator; 2-first supergravity machine; 3-condenser; 4-lean/rich liquid heat exchanger;

5-booster pump; 6-buffer tank; 7-reboiler; 8-second supergravity machine;

9-flash tank; 10-delivery pump; 11-first stop valve; 12-second stop valve

13-the third shut-off valve; 19-the fourth shut-off valve; 20-the fifth shut-off valve; 14-pressure reducing valve;

15-flow meter; 16-vacuum pump; 17-gas-liquid separator; 18-three-way valve.

detailed description

In order to illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

Referring to Fig. 1, a natural gas deep dehydration system device of the present invention includes a filter separator 1, a first supergravity machine 2, a condenser 3, a lean/rich liquid heat exchanger 4, a booster pump 5, and a buffer tank 6 , reboiler 7, second supergravity machine 8, flash tank 9, delivery pump 10, first shut-off valve 11, second shut-off valve 12, third shut-off valve 13, fourth shut-off valve 19, fifth shut-off valve 20. Pressure reducing valve 14, flow meter 15, vacuum pump 16, gas-liquid separator 17 and three-way valve 18;

The outlet of the filter separator 1 is connected to the gas phase inlet of the first supergravity machine 2, the gas phase outlet of the first supergravity machine 2 is connected to the inlet of the first stop valve 11, and the outlet of the first stop valve 11 leads to the downstream section ; The regeneration gas branch after the outlet of the first cut-off valve 11 is connected in series with the third cut-off valve 13, pressure reducing valve 14 and flow meter 15, and the outlet of the flow meter 15 is connected with the gas phase inlet of the reboiler 7;

The gas-phase outlet of the reboiler 7 is connected with the gas-phase inlet of the second supergravity machine 8, the gas-phase outlet of the second supergravity machine 8, the gas outlet of the buffer tank 6 and the vacuum pump 16 inlet three are connected with the tee The valve 18 is connected, and the vacuum pump 16 provides a negative pressure environment for the second supergravity machine 8, the reboiler 7, and the buffer tank 6; the liquid phase outlet of the reboiler 7 leads to the buffer tank through the second shut-off valve 12 6 imports;

The outlet of the vacuum pump 16 is connected with the gas phase inlet of the gas-liquid separator 17, and the gas phase outlet of the gas-liquid separator 17 leads to the reboiler 7 as its heating fuel;

The liquid phase outlet of the first supergravity machine 2 is connected to the rich liquid inlet of the lean/rich liquid heat exchanger 4, and the rich liquid outlet of the lean/rich liquid heat exchanger 4 is connected to the flash tank 9 inlet, so The gas phase outlet of the flash tank 9 also leads to the reboiler 7 as heating fuel, the liquid outlet of the flash tank 9 is connected to the inlet of the transfer pump 10, and the gas phase outlet of the flash tank 9 is connected to the gas-liquid separation Device 17; the outlet of the transfer pump 10 is connected with the liquid phase inlet of the second supergravity machine 8, and the liquid phase outlet of the second supergravity machine 8 is connected with the liquid phase inlet of the reboiler 7, and the reboiler The liquid phase outlet of the device 7 is connected to the inlet of the buffer tank 6 through the second stop valve 12, the liquid phase outlet of the buffer tank 6 is connected to the inlet of the booster pump 5, and the outlet of the booster pump 5 is connected to the lean/rich liquid heat exchanger 4 is connected to the lean liquid inlet, the lean liquid outlet of the lean/rich liquid heat exchanger 4 is connected to the inlet of the condenser 3, and the outlet of the condenser 3 is connected to the liquid phase inlet of the first supergravity machine 2 to realize Triethylene glycol cycle.

As a further improvement of the technical solution, a fourth cut-off valve 19 is also provided on the pipeline connecting the vacuum pump 16 and the three-way valve 18 .

As a further improvement of the technical solution, the gas phase outlet of the flash tank 9 is connected to the pipeline of the gas-liquid separator 17, and is connected to the three-way valve 18 through a branch pipeline, and the fifth shut-off valve 20 is provided on the branch pipeline. .

The present invention utilizes the dehydration method of the above-mentioned natural gas deep dehydration system device, comprising the following steps:

1), the natural gas raw material gas with a pressure of 2-10MPa is passed into the filter separator, and the liquid water and solid impurities are removed by gravity sedimentation;

2), the natural gas raw material gas discharged in step 1) enters the first supergravity machine from the gas phase inlet of the first supergravity machine, and the triethylene glycol poor liquid enters the first supergravity machine from the liquid phase inlet of the first supergravity machine, The liquid distributor is evenly sprayed on the wire mesh packing of the supergravity machine, the triethylene glycol flows from the inner ring to the outer ring of the packing, the natural gas raw material gas flows from the outer ring to the inner ring, and the gas-liquid two-phase flows along the diameter of the packing layer. In countercurrent contact, the water in the natural gas raw material gas is absorbed by the liquid-phase triethylene glycol, and the dehydrated natural gas leaves the first supergravity machine directly from the gas phase outlet of the supergravity machine, part of it is used as product gas, and a small part is taken as regeneration gas. After the gas is decompressed by the pressure reducing valve, it enters the reboiler;

3), the triethylene glycol rich liquid after water absorption in step 2) discharges the first supergravity machine from the liquid outlet of the first supergravity machine, and enters the flash tank after heat exchange with the triethylene glycol poor liquid;

4), the regenerated gas that enters from the bottom of the reboiler in step 2) is discharged from the outlet at the top of the reboiler after being contacted with triethylene glycol in the reboiler, and enters the second supergravity machine;

5), the triethylene glycol in step 3) is pumped into the second supergravity machine after being flashed by the flash tank, and the gas phase outlet of the second supergravity machine, the gas outlet of the buffer tank, and the vacuum pump are connected by a three-way valve, When opening the 4th shut-off valve and closing the 5th shut-off valve, the vacuum pump provides a single and stable negative pressure environment for the second supergravity machine, reboiler and surge tank; step 3) pumps into the third of the second supergravity machine The regeneration gas discharged from the reboiler in the glycol-rich solution and step 4) is countercurrently contacted and regenerated in a negative pressure environment; the regenerated triethylene glycol lean solution is discharged from the liquid phase outlet of the second supergravity machine; the regeneration gas is discharged from the second The gas phase outlet of the supergravity machine is discharged;

6), in step 5), the regeneration gas discharged from the gas phase outlet of the second supergravity machine is discharged by the vacuum pump and enters the gas-liquid separator, and can be used as a heating fuel for the reboiler after condensing and removing free liquid water;

7), in step 5), the triethylene glycol lean liquid flowing out from the second supergravity machine enters the reboiler, and after being contacted with the regeneration gas for the second time and fully replenishing heat, it is discharged from the liquid phase outlet of the reboiler;

8), step 7) the triethylene glycol barren solution discharged from the liquid phase outlet of the reboiler enters the buffer tank, forming a stable liquid level in the buffer tank;

9), the triethylene glycol poor liquid in the buffer tank in step 8) is transported to the lean/rich liquid heat exchanger by the booster pump; in the lean/rich liquid heat exchanger, it is exchanged with the triethylene glycol rich liquid in step 3) After being condensed by the condenser, it enters the first supergravity machine again to realize the circulation of triethylene glycol.

In some embodiments of the present invention, in step 2), the volume ratio of regeneration gas consumption to product gas is 1:1000-1:10000, or 1:1000-1:2000, or 1:1000-1:3000 , or 1:1000-1:4000, or 1:1000-1:5000, or 1:1000-1:6000, or 1:1000-1:7000, or 1:1000-1:8000, or 1:1000 -1: 9000.

In some embodiments of the present invention, in step 2), the volume ratio of triethylene glycol lean liquid to natural gas feed gas is 1:5000-1:50000, or 1:5000-1:45000, or 1:5000- 1:40000, or 1:5000-1:35000, or 1:5000-1:30000, or 1:5000-1:25000, or 1:5000-1:20000, or 1:5000-1:15000, or 1:5000-1:10000.

In some embodiments of the present invention, the supergravity level of the first supergravity machine in step 2) is 20-1000, or 50-1000, or 50-900, or 50-800, or 50-700, or 50 -600, or 50-500, or 50-400, or 50-300, or 50-200, or 50-100, or 100-1000, or 100-900, or 100-800, or 100-700, or 100 -600, or 100-500, or 100-400, or 100-300, or 100-200, or 300-1000, or 300-900, or 300-800, or 300-700, or 300-600, or 300 -500, or 300-400; the supergravity level of the second supergravity machine in step 5) is 20-1000, or 50-1000, or 50-900, or 50-800, or 50-700, or 50- 600, or 50-500, or 50-400, or 50-300, or 50-200, or 50-100, or 100-1000, or 100-900, or 100-800, or 100-700, or 100- 600, or 100-500, or 100-400, or 100-300, or 100-200, or 300-1000, or 300-900, or 300-800, or 300-700, or 300-600, or 300- 500, or 300-400.

Through the above-mentioned dehydration process of the present invention, the purity of triethylene glycol lean liquid in step 2) can reach 99.99wt%, and the dehydration treatment of natural gas can be carried out by using triethylene glycol of this purity, and the dew point of the natural gas outlet can reach below -35°C, and the minimum can be reduced to Below -45°C.

In some embodiments of the present invention, the vacuum degree of the second supergravity machine, reboiler and buffer tank in step 5) is 50-90kPa.

In some embodiments of the present invention, in step 7), the temperature of the reboiler is 160-204°C.

In some embodiments of the present invention, the temperature of the condenser in step 9) is 15-40°C.

Example 1

At the same time, adopt negative pressure enhanced regeneration and regeneration gas enhanced regeneration methods, use the above-mentioned device and process to remove water from natural gas with triethylene glycol: open the third stop valve 13, the fourth stop valve 19, and close the fifth stop valve 20.

The pressure of natural gas entering the system is 7MPa, the volume ratio of regeneration gas to product gas is 1:2000, the volume ratio of triethylene glycol lean liquid to natural gas raw material gas is 1:10000, and the supergravity level of No. 1 supergravity machine is 200, the supergravity level of the No. 2 supergravity machine is 200, the vacuum degree is 80kPa, the reboiler temperature is 190℃, and the condenser temperature is 30℃. Under this process condition, the purity of the triethylene glycol lean liquid after regeneration reaches about 99.99wt%, and the water dew point of the exported natural gas reaches below -50°C.

Example 2

As described in Example 1, other conditions remain unchanged, the supergravity level of the first supergravity machine is adjusted to 100, after this process, the purity of triethylene glycol lean liquid after regeneration reaches about 99.99wt%, and the dew point of natural gas water reaches Below -48°C.

Example 3

As described in Example 1, other conditions remain unchanged, the supergravity level of the first supergravity machine is adjusted to 20, after this process, the purity of triethylene glycol lean liquid after regeneration reaches about 99.99wt%, and the dew point of natural gas water reaches Below -28°C.

Example 4

As described in Example 1, other conditions remain unchanged, the supergravity level of the second supergravity machine is adjusted to 20, after this process, the purity of triethylene glycol lean liquid after regeneration reaches about 99.86wt%, and the dew point of natural gas water reaches Below -28°C.

Example 5

As described in Example 1, other conditions remain the same, the volume ratio of the triethylene glycol lean liquid to the natural gas feed gas is adjusted to 1:20000, after this process, the purity of the regenerated triethylene glycol lean liquid reaches about 99.99wt% , The water dew point of natural gas is below -35°C.

Example 6

As described in Example 1, other conditions remain unchanged, and the volume ratio of regeneration gas to product gas is adjusted to 1:10000. After this process, the purity of triethylene glycol lean liquid after regeneration reaches about 99.90wt%, and the natural gas water The dew point reaches below -36°C.

Example 7

As described in Example 1, other conditions remain unchanged, and the vacuum degree is adjusted to 60kPa. After treatment, the purity of the regenerated triethylene glycol lean liquid reaches about 99.93wt%, and the dew point of natural gas water reaches below -38°C.

Example 8

As described in Example 1, with other conditions unchanged, the temperature of the reboiler was adjusted to 160°C. After the treatment, the purity of the regenerated triethylene glycol barren liquid reached about 99.85wt%, and the dew point of natural gas water reached below -27°C.

Example 9

As described in Example 1, other conditions remain unchanged, and the temperature of the condenser is adjusted to 40°C. After treatment, the purity of the regenerated triethylene glycol lean liquid reaches about 99.99wt%, and the dew point of natural gas water reaches below -30°C.

Example 10

Regeneration gas is used alone to enhance regeneration, and the above-mentioned device and process are used to remove water from natural gas in depth with triethylene glycol.

As described in embodiment 1, other conditions are constant, open the 3rd shut-off valve 13, the 5th shut-off valve 20, close the 4th shut-off valve 19, this moment vacuum degree is 0kPa, after the treatment, the triethylene glycol barren liquid after regeneration The purity reaches about 99.86wt%, and the dew point of natural gas water reaches below -34°C.

Example 11

Use negative pressure to strengthen regeneration alone, and use the above-mentioned device and process to remove water from natural gas with triethylene glycol:

As described in Example 1, with other conditions unchanged, the fourth shut-off valve 19 is opened, the third shut-off valve 13 and the fifth shut-off valve 20 are closed. At this time, the regeneration gas consumption is 0 m ³ /h. The purity of the alcohol lean liquid reaches about 99.70wt%, and the dew point of natural gas water reaches below -28°C.

Comparative example 1

Neither negative pressure enhanced regeneration nor regeneration gas enhanced regeneration method is used for deep removal of water from natural gas with triethylene glycol using the above-mentioned device and process:

As described in Embodiment 1, other conditions remain unchanged, the fifth stop valve 20 is opened, the third stop valve 13 and the fourth stop valve 19 are closed, there is no regeneration gas at this time, and the vacuum degree is 0kPa. The purity of glycol lean liquid reaches about 98.85wt%, and the dew point of natural gas water reaches below -16°C.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. All the implementation manners cannot be exhaustively listed here. All obvious changes or variations derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims (10)

1. A natural gas deep dehydration system device, characterized in that: comprising a filter separator (1), a first supergravity machine (2), a condenser (3), a lean/rich liquid heat exchanger (4), a booster Pump (5), buffer tank (6), reboiler (7), second supergravity machine (8), flash tank (9), transfer pump (10), first stop valve (11), second Stop valve (12), third stop valve (13), fourth stop valve (19), fifth stop valve (20), pressure reducing valve (14), flow meter (15), vacuum pump (16), gas-liquid Separator (17) and three-way valve (18); The outlet of the filter separator (1) is connected with the gas phase inlet of the first supergravity machine (2), and the gas phase outlet of the first supergravity machine (2) is connected with the inlet of the first stop valve (11), and the first The outlet of the shut-off valve (11) leads to the downstream section; the regeneration gas branch after the outlet of the first shut-off valve (11) is connected in series with the third shut-off valve (13), pressure reducing valve (14) and flow meter (15), The outlet of flow meter (15) is connected with the gas phase inlet of reboiler (7); The gaseous phase outlet of described reboiler (7) is connected with the gaseous phase inlet of the second supergravity machine (8), the gaseous phase outlet of described second supergravity machine (8), the gas outlet of described surge tank (6) and The three inlets of the vacuum pump (16) are connected with the three-way valve (18), and the vacuum pump (16) provides a negative pressure environment for the second supergravity machine (8), the reboiler (7), and the buffer tank (6); The liquid outlet of the reboiler (7) leads to the buffer tank (6) inlet through the second stop valve (12); The outlet of the vacuum pump (16) is connected with the gas-phase inlet of the gas-liquid separator (17), and the gas-phase outlet of the gas-liquid separator (17) leads to the reboiler (7) as its heating fuel; The liquid phase outlet of the first supergravity machine (2) is connected to the rich liquid inlet of the lean/rich liquid heat exchanger (4), and the rich liquid outlet of the lean/rich liquid heat exchanger (4) is connected to the flash evaporation The tank (9) inlet is connected, and the gas phase outlet of the flash tank (9) also leads to the reboiler (7) as heating fuel, and the liquid outlet of the flash tank (9) is connected to the inlet of the transfer pump (10) Connected, the gas phase outlet of the flash tank (9) is connected to the gas-liquid separator (17); the outlet of the delivery pump (10) is connected with the liquid phase inlet of the second supergravity machine (8), and the first The liquid phase outlet of the second supergravity machine (8) is connected with the liquid phase inlet of the reboiler (7), and the liquid phase outlet of the reboiler (7) passes through the second stop valve (12) and the buffer tank (6) inlet connected, the liquid phase outlet of the buffer tank (6) is connected to the inlet of the booster pump (5), and the outlet of the booster pump (5) is connected to the lean liquid inlet of the lean/rich liquid heat exchanger (4), so The lean liquid outlet of the lean/rich liquid heat exchanger (4) is connected to the inlet of the condenser (3), and the outlet of the condenser (3) is connected to the liquid phase inlet of the first supergravity machine (2). 2. The natural gas deep dehydration system device according to claim 1, characterized in that: preferably, a fourth cut-off valve (19) is further provided on the pipeline connecting the vacuum pump (16) and the three-way valve (18). 3. The natural gas deep dehydration system device according to claim 1, characterized in that: preferably, on the pipeline where the gas phase outlet of the flash tank (9) is connected to the gas-liquid separator (17), through the branch pipeline It is connected with the three-way valve (18), and the fifth shut-off valve (20) is arranged on the branch pipeline. 4. Utilize the dehydration method of the natural gas deep dehydration system device described in any one of the above-mentioned claims 1-3, it is characterized in that, comprises the following steps: 1), the natural gas raw material gas with a pressure of 2-10MPa is passed into the filter separator, and the liquid water and solid impurities are removed by gravity sedimentation; 2), the natural gas raw material gas discharged in step 1) enters the first supergravity machine from the gas phase inlet of the first supergravity machine, and the triethylene glycol poor liquid enters the first supergravity machine from the liquid phase inlet of the first supergravity machine, The liquid distributor is evenly sprayed on the wire mesh packing of the supergravity machine, the triethylene glycol flows from the inner ring to the outer ring of the packing, the natural gas raw material gas flows from the outer ring to the inner ring, and the gas-liquid two-phase flows along the diameter of the packing layer. In countercurrent contact, the water in the natural gas raw material gas is absorbed by the liquid-phase triethylene glycol, and the dehydrated natural gas leaves the first supergravity machine directly from the gas phase outlet of the supergravity machine, a part of which is used as product gas, and a small part is taken as regeneration gas, and regeneration After the gas is decompressed by the pressure reducing valve, it enters the reboiler; 3), the triethylene glycol rich liquid after water absorption in step 2) discharges the first supergravity machine from the liquid outlet of the first supergravity machine, and enters the flash tank after heat exchange with the triethylene glycol poor liquid; 4), the regenerated gas that enters from the bottom of the reboiler in step 2) is discharged from the outlet at the top of the reboiler after being contacted with triethylene glycol in the reboiler, and enters the second supergravity machine; 5), the triethylene glycol in step 3) is pumped into the second supergravity machine after being flashed by the flash tank, and the gas phase outlet of the second supergravity machine, the gas outlet of the buffer tank, and the vacuum pump are connected by a three-way valve, When opening the 4th shut-off valve and closing the 5th shut-off valve, the vacuum pump provides a single and stable negative pressure environment for the second supergravity machine, reboiler and buffer tank; step 3) pumps into the third of the second supergravity machine The regeneration gas discharged from the reboiler in the glycol-rich solution and step 4) is countercurrently contacted and regenerated in a negative pressure environment; the regenerated triethylene glycol lean solution is discharged from the liquid phase outlet of the second supergravity machine; the regeneration gas is discharged from the second The gas phase outlet of the supergravity machine is discharged; 6), in step 5), the regeneration gas discharged from the gas phase outlet of the second supergravity machine is discharged by the vacuum pump and enters the gas-liquid separator, and can be used as a heating fuel for the reboiler after condensing and removing free liquid water; 7), in step 5), the triethylene glycol lean liquid flowing out from the second supergravity machine enters the reboiler, and after being contacted with the regeneration gas for the second time and fully replenishing heat, it is discharged from the liquid phase outlet of the reboiler; 8), step 7) the triethylene glycol barren solution discharged from the liquid phase outlet of the reboiler enters the buffer tank, forming a stable liquid level in the buffer tank; 9), the triethylene glycol poor liquid in the buffer tank in step 8) is transported to the lean/rich liquid heat exchanger by the booster pump; in the lean/rich liquid heat exchanger, it is exchanged with the triethylene glycol rich liquid in step 3) After being condensed by the condenser, it enters the first supergravity machine again to realize the circulation of triethylene glycol. 5. The dehydration method according to claim 4, characterized in that: preferably, in step 2), the volume ratio of regeneration gas consumption to product gas is 1:1000-1:10000, or 1:1000-1:2000, Or 1:1000-1:3000, or 1:1000-1:4000, or 1:1000-1:5000, or 1:1000-1:6000, or 1:1000-1:7000, or 1:1000- 1:8000, or 1:1000-1:9000. 6. The dehydration method according to claim 4, characterized in that: preferably, in step 2), the volume ratio of triethylene glycol lean liquid to natural gas feed gas is 1:5000-1:50000, or 1:5000-1 :45000, or 1:5000-1:40000, or 1:5000-1:35000, or 1:5000-1:30000, or 1:5000-1:25000, or 1:5000-1:20000, or 1 :5000-1:15000, or 1:5000-1:10000. 7. The dehydration method according to claim 4, characterized in that: preferably, in step 2), the supergravity level of the first supergravity machine is 20-1000, or 50-1000, or 50-900, or 50- 800, or 50-700, or 50-600, or 50-500, or 50-400, or 50-300, or 50-200, or 50-100, or 100-1000, or 100-900, or 100- 800, or 100-700, or 100-600, or 100-500, or 100-400, or 100-300, or 100-200, or 300-1000, or 300-900, or 300-800, or 300- 700, or 300-600, or 300-500, or 300-400; in step 5), the supergravity level of the second supergravity machine is 20-1000, or 50-1000, or 50-900, or 50-800 , or 50-700, or 50-600, or 50-500, or 50-400, or 50-300, or 50-200, or 50-100, or 100-1000, or 100-900, or 100-800 , or 100-700, or 100-600, or 100-500, or 100-400, or 100-300, or 100-200, or 300-1000, or 300-900, or 300-800, or 300-700 , or 300-600, or 300-500, or 300-400. 8. The dehydration method according to claim 4, characterized in that: preferably, the vacuum degree of the second supergravity machine, reboiler and surge tank in step 5) is 50-90kPa. 9. The dehydration method according to claim 4, characterized in that: preferably, in step 7), the temperature of the reboiler is 160-204°C. 10. The dehydration method according to claim 4, characterized in that: preferably, the temperature of the condenser in step 9) is 15-40°C.