CN107641536A - The system and device and technique handled suitable for offshore platform liquefaction with gas dehydration - Google Patents

Abstract

The invention discloses a natural gas dehydration treatment system and process suitable for offshore platform liquefaction, including a filter separator, a first supergravity machine, a triethylene glycol condenser, a lean/rich liquid heat exchanger, a booster pump, a buffer tank, and a Boiler, second supergravity machine, flash tank, delivery pump, first stop valve, second stop valve, third stop valve, stripping agent condenser, three-phase separator, stripping agent dryer, stripping agent storage tank, stripping agent pump, first flow meter, second flow meter and three-way valve. Both the dehydration of natural gas and the regeneration of triethylene glycol in the device of the present invention adopt a supergravity reactor, which can reduce the height and size of the equipment; the device of the present invention can increase the purity of the regenerated triethylene glycol lean liquid to 99.999wt%. Triethylene glycol lean liquid is used as an absorbent, which can reduce the dew point of natural gas outlet water treated by water absorption in the absorption system to below -100°C; it can meet the processing requirements of natural gas for liquefaction in places with limited space such as offshore platforms.

Description

System device and process suitable for dehydration treatment of natural gas for liquefaction on offshore platforms

technical field

The invention relates to the technical field of oil and natural gas treatment and processing, in particular to a system device and process suitable for dehydration treatment of natural gas used for liquefaction on offshore platforms.

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. In the past decade or so, the degree of onshore oil and gas exploration has been relatively high, and the scale of discovered oil and gas fields has been small, and the contribution of new reserves to the growth of world oil and gas reserves has decreased. In contrast, the world's offshore oil and gas exploration and development has developed rapidly, and major discoveries have been made continuously. The discovered oil and gas fields are large in scale and high in productivity, and their oil and gas production accounts for an increasing proportion of the world's total production. my country's offshore continental shelf is rich in natural gas resources. Accelerating the development and utilization of these resources has extremely important practical and strategic significance for alleviating my country's energy shortage and ensuring and promoting my country's economic development. At present, most oil and gas fields in my country are far away from the coast, and it is difficult to transport natural gas to land through pipelines after production. Therefore, it is necessary to liquefy natural gas on offshore platforms to facilitate ship transportation.

When natural gas is extracted from offshore oil and gas fields, it usually contains a large amount of water vapor. If the water vapor is not treated, it will form solid hydrates with hydrocarbons in natural gas during the low-temperature liquefaction process of natural gas. On the one hand, this solid hydrate may block the pipelines and equipment of the liquefaction system, and on the other hand, it may impact the high-pressure storage tank during the process of transporting liquefied natural gas by ship, generating static electricity and causing serious safety hazards. Therefore, before natural gas liquefaction, natural gas must be dehydrated to an extremely low content, so that its water dew point can reach below -100°C, so as to ensure that there is no solid water or solid hydrate condensed and precipitated in the liquid phase components during the natural gas liquefaction process, ensuring production and transportation safe operation of the device.

At present, the commonly used natural gas dehydration methods include solid adsorption method, solvent absorption method, freeze separation method and so on. Since liquefied natural gas requires the water dew point after dehydration to be below -100°C, the industrial dehydration treatment of liquefied natural gas generally adopts a solid adsorption method with a high dehydration depth, and this method requires a large basic investment and high energy consumption for adsorbent regeneration. Therefore, in the actual industrial production of liquefied natural gas, staged dehydration is generally adopted. First, triethylene glycol is used to dehydrate natural gas to remove most of the water in natural gas, and then the low content of water is removed by solid adsorption method to make it The water dew point reaches the required -100°C. However, this method also brings obvious disadvantages. On the one hand, two sets of devices, the triethylene glycol absorption method and the solid adsorption method, are used at the same time, which is not easy to pry, which increases the cost of the device. On the other hand, the traditional triethylene glycol dehydration Using tower equipment, the vapor-liquid mass transfer efficiency is low, and the height of the device is large. However, the offshore platform has a multi-layer deck structure. If the height of the device is greater than the height between layers, it is necessary to open holes on the deck, which will destroy the original mechanics of the platform. The structure affects the safe operation of the entire platform, so the offshore platform has very strict requirements on the height of the dehydration device, and it is difficult to apply taller tower equipment on the offshore platform.

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

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 triethylene glycol lean liquid to a minimum purity of 99.0%. Using this pure triethylene glycol solution for dehydration of natural gas, the water dew point temperature can be reduced to about -18°C, which can reach the gaseous state at normal ambient temperature. Requirements for natural gas pipeline transportation.

Chinese utility model patent CN201720055206 reports a movable skid-mounted natural gas dehydration device, which includes two parts: a triethylene glycol supergravity absorption device and a supergravity triethylene glycol regeneration device. Gas is used as a stripping gas to increase the purity of triethylene glycol after regeneration to about 99.8%. Using the triethylene glycol solution of this purity for natural gas dehydration is expected to further reduce the water dew point temperature of natural gas (theoretically, the water dew point temperature can be the lowest down to about -40°C). Even so, the water dew point of natural gas that can be obtained by using this patented device for dehydration treatment is still far from the dehydration treatment requirements of natural gas for liquefaction.

Therefore, it is necessary to develop a dehydration system and process with high dehydration efficiency, small device size, low height, and dehydration depth that can meet the requirements of natural gas dehydration for liquefaction. .

Contents of the invention

The first technical problem to be solved by the present invention is to provide a system device suitable for dehydration of natural gas used for liquefaction on offshore platforms; The absorbent can reduce the dew point of the natural gas outlet water treated by water absorption in the absorption system to below -100°C, meeting the dehydration treatment requirements of natural gas for liquefaction. 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 use the dehydration process of the above-mentioned system device suitable for the dehydration treatment of natural gas for liquefaction on offshore platforms.

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

The present invention is a system device suitable for dehydration treatment of natural gas used for liquefaction on offshore platforms, including a filter separator, a first supergravity machine, a triethylene glycol condenser, a lean/rich liquid heat exchanger, a booster pump, a buffer tank, and a Boiler, second supergravity machine, flash tank, delivery pump, first shut-off valve, second shut-off valve, third shut-off valve, stripping agent condenser, three-phase separator, stripping agent dryer, stripping Agent storage tank, stripping agent pump, first flow meter, second flow meter 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 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 liquid phase outlet of the tank is connected with the inlet of the delivery pump, and the gas phase outlet of the flash tank leads to tail gas treatment;

The outlet of the transfer pump is connected to the liquid phase inlet of the second supergravity machine, the liquid phase outlet of the second supergravity machine is connected to the liquid phase inlet of the reboiler, and the gas phase outlet of the second supergravity machine is connected to the The inlet of the stripping agent condenser is connected, the outlet of the stripping agent condenser is connected with the inlet of the three-phase separator, and the lower end of the three-phase separator is provided with a drain;

The non-condensable gas outlet of the three-phase separator leads to tail gas treatment, the stripping agent outlet of the three-phase separator is connected to the inlet of the stripping agent drier, and the outlet of the stripping agent drier is connected to the outlet of the three-way valve. The first inlet; the stripping agent storage tank, the third shut-off valve and the first flowmeter are connected in sequence, and finally the outlet of the first flowmeter is connected to the second inlet of the three-way valve; the outlet of the three-way valve is connected to the second inlet of the three-way valve. The inlet of the stripping agent pump is connected, and the outlet of the stripping agent pump is connected with the second flow meter inlet, and the second flow meter outlet is connected with the reboiler to realize the circulation of the stripping agent;

The gas phase outlet of the reboiler is connected to the gas phase inlet of the second supergravity machine, the liquid phase outlet of the reboiler is connected to the buffer tank inlet through the second stop valve, and the liquid phase outlet at the bottom of the buffer tank is connected to the booster pump The outlet of the booster pump is connected to the lean liquid inlet of the lean/rich liquid heat exchanger, the lean liquid outlet of the lean/rich liquid heat exchanger is connected to the condenser inlet, and the outlet of the condenser is connected to the The liquid phase inlet of the first supergravity machine is connected to realize the circulation of triethylene glycol.

In order to solve the above-mentioned second technical problem, the present invention utilizes the dehydration process of the above-mentioned system device suitable for the dehydration of natural gas used for liquefaction on offshore platforms, including the following steps:

1) Natural gas with a pressure of 5-20MPa enters the filter separator to remove free liquid water and solid impurities, and then it is discharged from the outlet of the filter separator;

2), the natural gas discharged in step 1) enters the first supergravity machine, and dehydrates in the first supergravity machine by countercurrent contact with triethylene glycol lean liquid, and the dehydrated dry gas is discharged from the system and enters the downstream section;

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

4), the triethylene glycol in the step 3) is pumped into the second supergravity machine through the transfer pump after flashing through the flash tank, and the triethylene glycol is mixed with the stripping agent from the reboiler gasification in the second supergravity machine Countercurrent contact, the water in the triethylene glycol migrates to the gas phase; on the one hand, the stripping agent forms an azeotrope with the water in the triethylene glycol, so that the water transfers to the gas phase in the form of an azeotrope; on the other hand, the gasification The stripping agent can enhance the turbulence of the liquid-phase triethylene glycol, reduce the water pressure of the gas phase, and promote the migration of water to the gas phase; the regenerated triethylene glycol is discharged from the liquid phase outlet of the second supergravity machine, and the stripping agent is discharged from the second The gas phase outlet of the supergravity machine is discharged;

5), the stripping agent discharged from the second supergravity machine gas phase outlet in step 4) enters the stripping agent condenser, discharges the stripping agent condenser after being condensed into a liquid state;

6), the stripping agent discharged from the stripping agent condenser in step 5) enters the three-phase separator, the water and the stripping agent are separated, the non-condensable gas leads to the tail gas treatment, the water is discharged from the system, and the stripping agent enters the stripping agent dryer;

7), the stripping agent that enters the stripping agent drier in step 6) further removes trace moisture wherein through drying, meanwhile, supplements the stripping agent lost in the stripping agent recovery process by the stripping agent storage tank; After that The stripping agent is transported to the reboiler with the stripping agent pump, and the stripping agent forms an azeotrope and degasses with water in the triethylene glycol rich liquid discharged from the second supergravity machine in the reboiler to achieve recycling of the stripping agent; triethylene glycol is discharged from the liquid phase outlet of the reboiler after further regeneration;

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, and is exchanged with the triethylene glycol rich liquid in step 3) in the lean/rich liquid heat exchanger After being condensed by the triethylene glycol 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 the triethylene glycol lean liquid to the natural gas raw material gas is 1:5000-1:10000.

As a further improvement of the technical solution, in step 2), the concentration of the triethylene glycol lean solution can reach 99.999%, and the dew point of the natural gas outlet water can reach below -100°C.

As a further improvement of the technical solution, in step 4), the stripping agent is one or more of substances capable of forming low-boiling azeotropes with water, such as isooctane, n-heptane, toluene, and ethylbenzene.

As a further improvement of the technical solution, in step 7), the volume ratio of the amount of the stripping agent to the amount of the triethylene glycol rich solution in step 4) is 0.15-0.5.

As a further improvement of the technical solution, in step 5), the temperature of the stripping agent condenser is 20°C-50°C

As a further improvement of the technical solution, the supergravity level of the first supergravity machine in step 2) is 100-500, and the supergravity level of the second supergravity machine in step 2) is 100-500.

As a further improvement of the technical solution, in step 7), the temperature of the reboiler is 190°C-204°C.

As a further improvement of the technical solution, in step 9), the temperature of the triethylene glycol condenser is 15°C-30°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) High dehydration depth. The present invention can form an azeotrope with the water in the rich liquid of triethylene glycol by introducing a stripping agent on the one hand, and on the other hand, after the stripping agent is vaporized, the turbulence of the liquid-phase triethylene glycol can also be enhanced by the effect of the stripping gas. Under the combined action of the above factors, the migration of water from the liquid phase to the gas phase is greatly promoted.

2) The purity of the regenerated triethylene glycol can be increased to 99.999wt% through the system and process proposed by the present invention, and the dew point of the natural gas outlet water treated by water absorption in the absorption system can be reduced by using the triethylene glycol lean liquid as an absorbent To below -100°C, meeting the dehydration treatment requirements of liquefied natural gas.

3) The device is small in size and low in height. Both the natural gas dehydration system and the triethylene glycol regeneration system in the system of the present invention use supergravity reactors. Therefore, this system has the advantages of supergravity technology: greatly increased gas-liquid contact area, improved gas-liquid mass transfer efficiency, low device height, small equipment size, easy start and stop, and is suitable for space-limited occasions such as offshore platforms.

Description of drawings

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

Figure 1. Schematic diagram of a natural gas dehydration treatment system suitable for liquefaction on offshore platforms

Numbers labeled in Figure 1:

1-filter separator; 2-the first supergravity machine; 3-triethylene glycol 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;

17-the third shut-off valve; 13-stripping agent condenser; 14-three-phase separator; 15-stripping agent drier;

16-stripping agent storage tank; 18-stripping agent pump; 19-first flow meter; 20-second flow meter; 21-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, the present invention is applicable to the natural gas dehydration treatment system for offshore platform liquefaction, including a filter separator 1, a first supergravity machine 2, a triethylene glycol condenser 3, a lean/rich liquid heat exchanger 4, a pressurized Pump 5, 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 17, stripping agent condensation Device 13, three-phase separator 14, stripping agent drier 15, stripping agent storage tank 16, stripping agent pump 18, first flowmeter 19, second flowmeter 20 and three-way valve 21;

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 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 liquid phase 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 leads to tail gas treatment;

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 second supergravity machine The gas phase outlet of 8 is connected with the stripping agent condenser 13 inlets, and the stripping agent condenser 13 outlets are connected with the three-phase separator 14 inlets, and the lower end of the three-phase separator 14 is provided with a drain;

The non-condensable gas outlet of the three-phase separator 14 leads to tail gas treatment, the stripping agent outlet of the three-phase separator 14 is connected with the stripping agent drier 15 inlet, and the stripping agent drier 15 outlet is connected to The first inlet of the three-way valve 21; the stripping agent storage tank 16, the third shut-off valve 17 are connected with the first flowmeter 19 in sequence, and the outlet of the first flowmeter 19 is connected to the second inlet of the three-way valve 21 at last On; the outlet of the three-way valve 21 is connected with the inlet of the stripping agent pump 18, the outlet of the stripping agent pump 18 is connected with the inlet of the second flowmeter 20, and the outlet of the second flowmeter 20 is connected with the reboiler 7 connections to realize the circulation of the stripping agent;

The gas phase outlet of the reboiler 7 is connected with the gas phase inlet of the second supergravity machine 8, the liquid phase outlet of the reboiler 7 is connected with the buffer tank 6 inlet through the second stop valve 12, and the liquid at the bottom of the buffer tank 6 is The phase outlet is connected to the inlet of the booster pump 5, the outlet of the booster pump 5 is connected to the lean liquid inlet of the lean/rich liquid heat exchanger 4, and the lean liquid outlet of the lean/rich liquid heat exchanger 4 is connected to the condenser 3 inlets are connected, and the outlet of the condenser 3 is connected with the liquid phase inlet of the first supergravity machine 2 to realize the circulation of triethylene glycol.

The present invention utilizes the dehydration process of the above-mentioned system device suitable for natural gas dehydration treatment for offshore platform liquefaction, comprising the following steps:

1) Natural gas with a pressure of 5-20MPa enters the filter separator to remove free liquid water and solid impurities, and then it is discharged from the outlet of the filter separator;

2), the natural gas discharged in step 1) enters the first supergravity machine, and in the first supergravity machine, it is dehydrated by countercurrent contact with triethylene glycol lean liquid, and the dehydrated dry gas discharge system enters the downstream section;

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

4), the triethylene glycol in the step 3) is pumped into the second supergravity machine through the transfer pump after flashing through the flash tank, and the triethylene glycol is mixed with the stripping agent from the reboiler gasification in the second supergravity machine Countercurrent contact, the water in the triethylene glycol migrates to the gas phase; on the one hand, the stripping agent forms an azeotrope with the water in the triethylene glycol, so that the water transfers to the gas phase in the form of an azeotrope; on the other hand, the gasification The stripping agent can enhance the turbulence of the liquid-phase triethylene glycol, reduce the water pressure of the gas phase, and promote the migration of water to the gas phase; the regenerated triethylene glycol is discharged from the liquid phase outlet of the second supergravity machine, and the stripping agent is discharged from the second The gas phase outlet of the supergravity machine is discharged;

5), the stripping agent discharged from the second supergravity machine gas phase outlet in step 4) enters the stripping agent condenser, discharges the stripping agent condenser after being condensed into a liquid state;

6), the stripping agent discharged from the stripping agent condenser in step 5) enters the three-phase separator, the water and the stripping agent are separated, the non-condensable gas leads to the tail gas treatment, the water is discharged from the system, and the stripping agent enters the stripping agent dryer;

7), the stripping agent that enters the stripping agent drier in step 6) further removes trace moisture wherein through drying, meanwhile, supplements the stripping agent lost in the stripping agent recovery process by the stripping agent storage tank; After that The stripping agent is transported to the reboiler with the stripping agent pump, and the stripping agent forms an azeotrope and degasses with water in the triethylene glycol rich liquid discharged from the second supergravity machine in the reboiler to achieve recycling of the stripping agent; triethylene glycol is discharged from the liquid phase outlet of the reboiler after further regeneration;

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, and is exchanged with the triethylene glycol rich liquid in step 3) in the lean/rich liquid heat exchanger After being condensed by the triethylene glycol 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 triethylene glycol lean liquid to natural gas feed gas is 1:5000-1:10000, or 1:5000-1:6000, or 1:5000- 1:7000, or 1:5000-1:8000, or 1:5000-1:9000.

In some embodiments of the present invention, in step 2), the concentration of the triethylene glycol lean solution can reach 99.999%, and the dew point of the natural gas outlet water can reach below -100°C.

In some embodiments of the present invention, in step 4), the stripping agent is one or more of substances that can form low-boiling azeotropes with water, such as isooctane, n-heptane, toluene, and ethylbenzene. Various.

In some embodiments of the present invention, in step 7), the volume ratio of the amount of stripping agent used in step 4) to the amount of triethylene glycol rich solution used is 0.15-0.5.

In some embodiments of the present invention, in step 5), the temperature of the stripping agent condenser is 20°C-50°C.

In some embodiments of the present invention, the supergravity level of the first supergravity machine in step 2) is 100-500, or 100-400, or 100-300, or 100-200, or 200-500, or 200 -400, or 200-300, or 300-500, or 300-400, or 400-500; the supergravity level of the second supergravity machine in step 2) is 100-500, or 100-400, or 100- 300, or 100-200, or 200-500, or 200-400, or 200-300, or 300-500, or 300-400, or 400-500.

In some embodiments of the present invention, in step 7), the temperature of the reboiler is 190°C-204°C.

In some embodiments of the present invention, in step 9), the temperature of the triethylene glycol condenser is 15°C-30°C.

Example 1

Using the above-mentioned device and process for deep removal of water from natural gas with triethylene glycol:

The pressure of natural gas entering the system is 7MPa, the volume ratio of triethylene glycol lean liquid to natural gas raw material gas is 1:10000, the ratio of the amount of stripping agent to the amount of triethylene glycol rich liquid is 0.15:1, and the stripping agent is positive The temperature of the heptane and triethylene glycol condenser is 30°C, the supergravity level of the first supergravity machine is 200, the supergravity level of the second supergravity machine is 200, and the reboiler temperature is 200°C; under this process condition, After regeneration, the purity of triethylene glycol lean liquid reaches about 99.999wt%, and the water dew point of exported natural gas reaches below -104°C.

Example 2

As described in Example 1, other conditions remain unchanged, the supergravity level of the first supergravity machine speed is adjusted to 100, after this process, the purity of triethylene glycol barren liquid after regeneration reaches about 99.999wt%, and the natural gas water dew point Reach below -100°C.

Example 3

As described in Example 1, other conditions remain unchanged, the temperature of the TEG condenser is adjusted to 20°C, after this process, the purity of the TEG barren liquid after regeneration reaches about 99.999wt%, and the dew point of natural gas water reaches -107 below ℃.

Example 4

As described in Example 1, other conditions remain unchanged, the stripping agent is replaced by a mixture of 50% isooctane and 50% n-heptane, after the process, the purity of the triethylene glycol barren liquid after regeneration reaches 99.999wt %, the water dew point of natural gas reaches below -102°C.

Example 5

As described in Example 1, other conditions remain unchanged, the supergravity level of the second supergravity machine is adjusted to 100, after this process, the purity of triethylene glycol barren liquid after regeneration reaches about 99.998wt%, and the dew point of natural gas water reaches Below -100°C.

Comparative example 1

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 99.999wt%, and the dew point of natural gas water reaches Below -88°C.

Comparative example 2

As described in Example 1, other conditions remain the same, the temperature of the reboiler is adjusted to 170°C, after this process, the purity of the regenerated triethylene glycol barren liquid reaches about 99.991wt%, and the dew point of natural gas water reaches below -62°C .

Comparative example 3

As described in Example 1, other conditions remain unchanged, the temperature of the TEG condenser is adjusted to 40°C, after this process, the purity of the TEG barren liquid after regeneration reaches about 99.999wt%, and the dew point of natural gas water reaches -96 below ℃.

Comparative example 4

As described in Example 1, other conditions remain unchanged, the ratio of the amount of stripping agent to the amount of triethylene glycol rich liquid is adjusted to 0.05:1, after this process, the purity of the regenerated triethylene glycol lean liquid reaches 99.992wt %, the water dew point of natural gas reaches below -80°C.

Comparative 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 1:20000, after this process, the purity of the triethylene glycol lean liquid after regeneration reaches about 99.999wt%, The water dew point of natural gas reaches below -82°C.

Comparative example 6

As described in Example 1, other conditions remain unchanged, the stripping agent pump is closed, and there is no longer the participation of stripping agent in the system. After this process, the purity of the triethylene glycol lean liquid after regeneration reaches about 99.100wt%, and the natural gas The water dew point is below -18°C.

It can be seen from the above examples and comparative examples that during the implementation of the system device and process proposed by the present invention, the purity of the triethylene glycol barren liquid after regeneration can be significantly improved in the regeneration link, and the triethylene glycol of this purity is used as the absorption Natural gas dehydration treatment can greatly increase the dehydration depth of natural gas. After system and process optimization, it can directly meet the dehydration treatment requirements of natural gas for liquefaction.

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 (9)

1. use gas dehydration processing system suitable for offshore platform liquefaction, it is characterised in that：Including filter separator (1), One hypergravity machine (2), triethylene glycol condenser (3), lean/rich liquid heat exchanger (4), booster pump (5), surge tank (6), reboiler (7), Second hypergravity machine (8), flash tank (9), delivery pump (10), the first stop valve (11), the second stop valve (12), the 3rd stop valve (17), steam stripping agent condenser (13), three phase separator (14), steam stripping agent drier (15), steam stripping agent storage tank (16), steam stripping agent pump (18), first flowmeter (19), second flowmeter (20) and triple valve (21)；

The outlet of the filter separator (1) is connected with the gas phase import of the first hypergravity machine (2), first hypergravity machine (2) gaseous phase outlet is connected with the first stop valve (11) import, and the first stop valve (11) outlet leads to downstream section；

The liquid-phase outlet of first hypergravity machine (2) is connected with the rich solution import of lean/rich liquid heat exchanger (4), the lean/rich liquid The rich solution outlet of heat exchanger (4) is connected with flash tank (9) import, liquid-phase outlet and the delivery pump (10) of the flash tank (9) Import connects, and the gaseous phase outlet of the flash tank (9) leads to vent gas treatment；

The outlet of the delivery pump (10) is connected with the fluid inlet of the second hypergravity machine (8), second hypergravity machine (8) Liquid-phase outlet is connected with the fluid inlet of reboiler (7), gaseous phase outlet and the steam stripping agent condenser of second hypergravity machine (8) (13) import is connected, and steam stripping agent condenser (13) outlet is connected with three phase separator (14) import, the three phase separator (14) lower end sets discharge outlet；

The fixed gas outlet of the three phase separator (14) leads to vent gas treatment, the steam stripping agent outlet of the three phase separator (14) It is connected with steam stripping agent drier (15) import, steam stripping agent drier (15) outlet is connected to the first of triple valve (21) and entered Mouthful；The steam stripping agent storage tank (16), the 3rd stop valve (17) are sequentially connected with first flowmeter (19), first flowmeter (19) Outlet is connected in the second import of triple valve (21)；The outlet of the triple valve (21) connects with the import of steam stripping agent pump (18) Connect, the outlet of the steam stripping agent pump (18) is connected with second flowmeter (20) import, the second flowmeter (20) outlet with again Device (7) connection is boiled, realizes the circulation of steam stripping agent；

Reboiler (7) gaseous phase outlet is connected with the gas phase import of the second hypergravity machine (8), the liquid phase of the reboiler (7) Outlet is connected through the second stop valve (12) with surge tank (6) import, surge tank (6) the bottom liquid phases outlet and booster pump (5) Import is connected, and the outlet of the booster pump (5) is connected with the lean solution import of lean/rich liquid heat exchanger (4), the lean/rich liquid heat exchange The lean solution outlet of device (4) is connected with condenser (3) import, the outlet of the condenser (3) and the liquid phase of the first hypergravity machine (2) Import is connected, and realizes the circulation of triethylene glycol.

2. utilize the dehydration for being applied to the system and device that offshore platform liquefaction is handled with gas dehydration described in the claims 1 Technique, it is characterised in that comprise the following steps：

1), pressure is that 5-20MPa natural gas enters filter separator, removes free aqueous water and solid impurity, Zhi Houyou Filter separator outlet discharge；

2), the natural gas of discharge enters the first hypergravity machine in step 1), in the first hypergravity machine with triethylene glycol lean solution countercurrently Contact dehydration, the dry gas removal system after dehydration, into downstream section；

3) the triethylene glycol rich solution after, being absorbed water in step 2) discharges the first hypergravity machine, is dodged with entering after the heat exchange of triethylene glycol lean solution Steaming pot；

4), the triethylene glycol in step 3) is pumped into the second hypergravity machine after flash tank flashes through delivery pump, and triethylene glycol is second With the steam stripping agent counter current contacting from reboiler gasification in hypergravity machine, water in triethylene glycol is to gas-migration；The side of steam stripping agent one Face forms a kind of azeotropic mixture with the water in triethylene glycol so that and water is shifted in the form of azeotropic mixture to gas phase, on the other hand, gasification Steam stripping agent can strengthen the turbulence of liquid phase triethylene glycol, reduce gas phase water partial pressure, promote migration of the water to gas phase；Three after regeneration are sweet Alcohol is discharged from the second hypergravity machine liquid-phase outlet, and steam stripping agent is discharged from the gaseous phase outlet of the second hypergravity machine；

5), enter steam stripping agent condenser from the steam stripping agent of the second hypergravity machine gaseous phase outlet discharge in step 4), be condensed into liquid Steam stripping agent condenser is discharged afterwards；

6), three phase separator, water and steam stripping agent separation, fixed gas are entered from the steam stripping agent of steam stripping agent condenser discharge in step 5) Towards vent gas treatment, water discharge system, steam stripping agent enters steam stripping agent drier；

7) steam stripping agent for, entering steam stripping agent drier in step 6) further removes micro-moisture therein by drying, meanwhile, The steam stripping agent lost in steam stripping agent removal process is replenished by steam stripping agent storage tank；Steam stripping agent is conveyed with steam stripping agent pump afterwards Into reboiler, the water in the triethylene glycol rich solution that steam stripping agent is discharged in reboiler with step 4) from the second hypergravity machine is formed altogether Boiling thing simultaneously gasifies, and realizes the recycling of steam stripping agent；Triethylene glycol is discharged after further regeneration from reboiler liquid-phase outlet；

8), the triethylene glycol lean solution that step 7) is discharged from reboiler liquid-phase outlet enters surge tank, and stabilizing solution is formed in surge tank Position；

9), the triethylene glycol lean solution in step 8) in surge tank is pumped into lean/rich liquid heat exchanger by being pressurized, and is exchanged heat in lean/rich liquid Exchanged heat in device with triethylene glycol rich solution in step 3), be again introduced into the first hypergravity machine after the condensation of triethylene glycol condenser afterwards, Realize the circulation of triethylene glycol.

3. it is applied to the dehydration work for the system and device that offshore platform liquefaction is handled with gas dehydration according to claim 2 Skill, it is characterised in that：In step 2), the volume ratio of triethylene glycol lean solution and natural gas _ raw material gas is 1：5000-1：10000, or 1： 5000-1：6000, or 1：5000-1：7000, or 1：5000-1：8000, or 1：5000-1：9000.

4. it is applied to the dehydration work for the system and device that offshore platform liquefaction is handled with gas dehydration according to claim 2 Skill, it is characterised in that：In step 4), the steam stripping agent is that isooctane, normal heptane, toluene, ethylbenzene etc. can form low boiling with water One or more in the material of azeotropic mixture.

5. it is applied to the dehydration work for the system and device that offshore platform liquefaction is handled with gas dehydration according to claim 2 Skill, it is characterised in that：In step 7), the ratio between the steam stripping agent dosage and volume of triethylene glycol rich solution dosage in step 4) are 0.15-0.5。

6. it is applied to the dehydration work for the system and device that offshore platform liquefaction is handled with gas dehydration according to claim 2 Skill, it is characterised in that：In step 5), the temperature of steam stripping agent condenser is 20 DEG C -50 DEG C.

7. it is applied to the dehydration work for the system and device that offshore platform liquefaction is handled with gas dehydration according to claim 2 Skill, it is characterised in that：The hypergravity level of the first hypergravity machine is 100-500 in step 2), or 100-400, or 100-300, Or 100-200, or 200-500, or 200-400, or 200-300, or 300-500, or 300-400, or 400-500；Step 2) In the hypergravity level of the second hypergravity machine be 100-500, or 100-400, or 100-300, or 100-200, or 200- 500, or 200-400, or 200-300, or 300-500, or 300-400, or 400-500.

8. it is applied to the dehydration work for the system and device that offshore platform liquefaction is handled with gas dehydration according to claim 2 Skill, it is characterised in that：In step 7), reboiler temperature is 190 DEG C -204 DEG C.

9. it is applied to the dehydration work for the system and device that offshore platform liquefaction is handled with gas dehydration according to claim 2 Skill, it is characterised in that：In step 9), the temperature of triethylene glycol condenser is 15 DEG C -30 DEG C.