An energy-saving and environment-friendly triethylene glycol dehydration device and dehydration process

Abstract

The present invention relates to an energy-saving and environment-friendly triethylene glycol dehydration device. It mainly solves the problems of poor dehydration effect, high energy consumption and environmental unfriendliness of the existing triethylene glycol dehydration device. Its characteristics are as follows: the glycol solution pipeline after heat exchange at the top of the regenerator tower condenser is connected to the exhaust gas cooling system and the supergravity separation buffer system; the glycol outlet pipeline of the supergravity separation buffer system is connected to the flash tank; the bottom pipeline of the flash tank is connected to the filter, heat exchanger, regenerator tower, reboiler and glycol lean liquid buffer tank; the bottom pipeline of the glycol lean liquid buffer tank is connected to the side pipeline at the top of the absorption tower through a gas / glycol heat exchanger; the outlet pipeline at the top of the regenerator tower is connected to the inlet pipeline at the top of the exhaust gas cooling system; the gas outlet of the exhaust gas cooling system is connected to the gas inlet of the vacuum compression unit system. This energy-saving and environment-friendly triethylene glycol dehydration device and dehydration process can improve the dehydration effect, reduce the energy consumption of equipment operation, avoid environmental pollution and eliminate potential safety hazards.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum engineering, and particularly relates to an energy-saving and environment-friendly triethylene glycol dehydration device and dehydration process. Background Art

[0002] The triethylene glycol dehydration device utilizes the strong hygroscopicity of the triethylene glycol solution to absorb moisture in the gas in the dehydration tower to achieve the purpose of drying the gas; the triethylene glycol solution that has absorbed moisture is then regenerated by removing the moisture through heating and recycled.

[0003] The process flow of a conventional triethylene glycol dehydration device is as Figure 1 shown. Since the decomposition temperature of triethylene glycol is 206°C, the conventional triethylene glycol dehydration device can only be heated to 200°C for triethylene glycol regeneration. At this time, the regeneration concentration of triethylene glycol is 98.9%, and the dehydration effect is low. The dew point depression is only 20 - 40°C. To improve the dehydration effect, the conventional device uses a stripping gas addition method to further concentrate. When the stripping gas flow rate in the stripping gas pipeline (107) is 20 - 200 m 3 / h, the glycol regeneration concentration is 99.3 - 99.9%, and the dew point depression is 40 - 70°C. This part of the stripping gas is directly discharged into the atmosphere at the top of the regenerator. The components of the gas discharged from the top of the regenerator include natural gas, hydrocarbons, alcohols, and water vapor that are dissolved in the glycol and vaporized by heating. In particular, the aromatic hydrocarbons in natural gas are extremely soluble in triethylene glycol. These aromatic hydrocarbons are benzene, toluene, and xylene, which have been clearly identified as carcinogens by modern medicine. Their boiling points are 80 - 150°C, which is lower than the 200°C regeneration heating temperature of triethylene glycol. They will vaporize from the triethylene glycol solution along with the water vapor and diffuse into the atmosphere, not only causing waste of resources, increasing operating energy consumption, but also seriously polluting the environment, endangering human health, and posing a potential fire and safety hazard. Therefore, a pungent smell can often be smelled in gas gathering stations and purification plants using conventional triethylene glycol dehydration devices.

[0004] Triethylene glycol requires dehydration at normal temperature and high pressure and regeneration at high temperature and normal pressure. To ensure the dehydration effect and meet the equipment usage requirements, the triethylene glycol dehydration device is equipped with various types of heat exchangers: shell-and-tube, plate, double-pipe, coil, finned, etc. A lot of heat is wasted and dissipated into the atmosphere. The decomposition temperature of triethylene glycol is only 206°C. When the regeneration temperature of triethylene glycol is 200°C, local overheating is likely to occur at the heating furnace tube part or triethylene glycol decomposition may occur due to improper temperature control. To avoid corrosion of the equipment by the acidic products of triethylene glycol decomposition, a pH regulator and corrosion inhibitor need to be added regularly.

[0005] Therefore, the disadvantages of this conventional triethylene glycol dehydration device are poor dehydration effect, high equipment operating energy consumption, polluted exhaust gas that endangers human health, and great potential safety hazards. Summary of the Invention

[0006] The present invention aims to overcome the problems in the background art, namely, the poor dehydration effect, high energy consumption, and environmental unfriendliness of the existing triethylene glycol dehydration device. It provides an energy-saving and environment-friendly triethylene glycol dehydration device, which can improve the dehydration effect, reduce the energy consumption during equipment operation, avoid environmental pollution, and eliminate potential safety hazards. The present invention also provides an energy-saving and environment-friendly triethylene glycol dehydration process.

[0007] The problems of the present invention can be solved through the following technical solutions: An energy-saving and environment-friendly triethylene glycol dehydration device includes an absorption tower. The bottom pipeline of the absorption tower is connected to the top condenser of the regenerator through a glycol pump. The glycol solution pipeline after heat exchange at the top of the regenerator is connected to an exhaust gas cooling system and a high-gravity separation and buffering system. The glycol outlet pipeline of the high-gravity separation and buffering system is connected to a flash tank. The bottom pipeline of the flash tank is connected to a filter, a heat exchanger, a regenerator, a reboiler, and a lean glycol buffer tank. The bottom pipeline of the lean glycol buffer tank is connected to the side pipeline at the top of the absorption tower through a gas / glycol heat exchanger. The top outlet pipeline of the regenerator is connected to the top inlet pipeline of the exhaust gas cooling system.

[0008] The exhaust gas cooling system includes a cooling outer pipe, a cooling inner pipe, and a buffer tank. The cooling inner pipe is installed in the center of the cooling outer pipe. The top opening of the cooling outer pipe is the exhaust gas inlet. The outer wall of the cooling outer pipe has outer fins. The top of the cooling inner pipe passes through the elbow opening end of the outer wall of the cooling outer pipe and is the glycol outlet. The middle and upper parts of the outer wall of the cooling inner pipe have inner fins. The lower ends of the cooling outer pipe and the cooling inner pipe pass through the center of the top of the buffer tank and enter the buffer tank. The outside of the buffer tank is provided with a tank body heat preservation shell. The bottom of the buffer tank has a liquid outlet. The bottom of the cooling inner pipe passes through the elbow opening end of the outer wall of the buffer tank and is the glycol inlet. The upper part of the buffer tank has a gas outlet. The glycol outlet is connected to the lower glycol inlet of the high-gravity separation and buffering system. The gas outlet is connected to the gas inlet pipeline of the vacuum compression unit system.

[0009] The high-gravity separation and buffering system includes a tank body. The upper right end of the tank body is connected to the main body of the gas-liquid separation section. The upper part of the separation section main body is connected with a gas-liquid inlet, and the gas-liquid inlet is connected to a high-gravity separation swirl tube. A number of exhaust holes are distributed on the inner wall of the high-gravity separation swirl tube. A fine separation and demisting component is installed at the left end inside the tank body. A gas outlet is opened on the tank body corresponding to the fine separation and demisting component, and the gas outlet is connected to a back pressure valve. A liquid outlet is opened on the lower part of the tank body below the gas outlet. The lower right end of the tank body is provided with a glycol inlet and a glycol outlet. A glycol heat exchange coil is installed at the lower part of the tank body on the right side of the weir plate.

[0010] The vacuum compression unit system includes a booster pump and a booster cylinder; one end of the booster pump is connected to the liquid inlet through a valve, and the other end is connected to the liquid inlet cavity through the high-pressure liquid inlet; the right side of the liquid inlet cavity is connected to the small-diameter end of the expansion pipe, and the left side of the liquid inlet cavity is connected to the air inlet cavity through a sealing ring; the upper left side of the air inlet cavity is connected to an electric push rod, and the middle left side is connected to the gas inlet pipeline through a sealing ring; the left side of the gas inlet pipeline is connected to a vacuum pressure transmitter; the electric push rod is fixed on the liquid inlet cavity and the expansion pipe, and the large-diameter end of the expansion pipe is connected to the mixed liquid outlet; the booster pump and the valve are fixed on the skid base; on the left and right sides of the outer end of the booster cylinder body, pipelines are respectively connected. There is an air supplement port on the upper side of the left pipeline, and the outlet of the left pipeline is the gas inlet; the air supplement port is connected to the gas outlet through a vacuum pressure transmitter and an air supplement valve; there is a gas outlet on the right pipeline of the booster cylinder; the booster cylinder is respectively communicated with the gas inlet and the gas outlet through one-way valves; the booster piston located inside the booster cylinder is connected to the power piston located inside the power cylinder through a piston rod; on the left and right sides inside the power cylinder body, a reversing valve A and a reversing valve B are arranged; the other end of the left end of the power cylinder body is connected to the end of the pipeline, which is the driving gas inlet, and a speed regulating valve is connected to the pipeline; the power cylinder is communicated with the driving gas inlet through a one-way valve and a speed regulating valve, and the power cylinder is communicated with the driving gas outlet through a one-way valve; the reversing valve A and the reversing valve B are respectively communicated with the driving gas inlet and the driving gas outlet through a reversing module;

[0011] The vacuum compression unit system has 7 interfaces: the gas inlet is connected to the gas outlet of the supergravity separator separation buffer system, the gas outlet is connected to the low-pressure fuel gas pipeline, the driving gas inlet is connected to the high-pressure fuel gas pipeline, and the driving gas outlet is connected to the low-pressure fuel gas pipeline; the gas inlet pipeline is connected to the gas outlet of the exhaust gas cooling system, the mixed liquid outlet is connected to the gas-liquid inlet of the supergravity separator separation buffer system, and the liquid inlet is connected to the liquid outlet of the supergravity separator separation buffer system.

[0012] The exhaust gas cooling system has 5 interfaces. Its glycol inlet is connected to the outlet of the regenerator top condenser; the gas outlet is connected to the gas inlet pipeline of the vacuum compression unit system; the exhaust gas inlet is connected to the exhaust gas outlet of the regenerator; the glycol outlet is connected to the lower glycol inlet of the supergravity separation buffer system; the liquid outlet is connected to the station sewage pipeline;

[0013] The supergravity separation buffer system has 5 interfaces. The gas-liquid inlet is connected to the mixed liquid outlet of the vacuum compression unit system; the gas outlet is connected to the gas inlet of the vacuum compression unit system; the liquid outlet is connected to the sewage pipeline in one way and the liquid inlet of the vacuum compression unit system in the other way; the lower glycol inlet is connected to the glycol outlet of the exhaust gas cooling system; the glycol outlet is connected to the glycol inlet pipeline of the flash tank.

[0014] The present invention also provides a triethylene glycol dehydration process method, including the following steps:

[0015] 1) The gas to be dried enters the lower part of the absorption tower. Inside the absorption tower, it contacts countercurrently with the glycol solution flowing downward from the top of the absorption tower from bottom to top. The moisture in the gas is absorbed by the glycol solution, then enters the gas / glycol heat exchanger to exchange heat with the glycol solution and leaves the device; the glycol solution that has absorbed moisture enters the top condenser of the regenerator from the lower part of the absorption tower through the glycol pump. The heat-exchanged glycol solution then enters the exhaust gas cooling system and the high-gravity separation buffer system in sequence to exchange heat and increase in temperature, and then enters the flash tank for flash separation; the exhaust gas containing moisture and some hydrocarbons enters the exhaust gas cooling system, the vacuum compressor unit system, and the high-gravity separation buffer system in sequence at the top of the regenerator; the vacuum compressor unit system is connected to the pipeline at the top of the regenerator through the exhaust gas cooling system to create a vacuum environment inside the regenerator, with the pressure controlled at 10 - 100 kPa(A). Adjust the burner to control the operating temperature of the reboiler at 160 - 200 °C, and at the same time increase the pressure of the gas outlet to 110 - 400 kPa(A); the regenerator exhaust gas is condensed, cooled, pressurized, and separated into gas and liquid. The gas enters the fuel gas system, and the liquid enters the sewage system;

[0016] 2) The glycol solution separated in the flash tank enters the filter to filter out the impurities therein, and then enters the glycol lean / rich liquid heat exchanger. After heat exchange, the glycol solution is heated to 160 - 200 °C by the burner in the reboiler and regenerated in combination with the vacuum generated by the vacuum compressor unit system; the regenerated glycol solution enters the glycol lean liquid buffer tank to dissipate heat and be stored, and then after heat exchange and cooling, it is pressurized by the glycol pump and enters the gas / glycol heat exchanger. After heat exchange and cooling, it enters the upper part of the absorption tower from the top for cyclic dehydration;

[0017] 3) The glycol solution after heat exchange through the top condenser of the regenerator enters the cooling inner tube of the exhaust gas cooling system through the bottom glycol inlet and flows upward. The regenerator exhaust gas enters the exhaust gas cooling system from the top and flows downward; the exhaust gas spirally flows downward through the channels composed of the cooling outer tube, the cooling inner tube, and the inner fins. The low-boiling substances such as water vapor therein are condensed into liquids by the low-temperature air and glycol, and flow downward along the side close to the cooling inner tube in the V-shaped grooves formed by the cooling inner tube and the inner fins. The glycol solution is used to cool the exhaust gas at normal temperature; after the glycol solution recovers the heat of the regenerator exhaust gas, its temperature is increased from 20 - 50 °C to 40 - 70 °C, and at the same time the temperature of the exhaust gas is decreased from 90 - 100 °C to 40 - 80 °C; the heated glycol solution enters the high-gravity separation buffer system as a heat source through the glycol outlet and the glycol inlet pipeline;

[0018] The condensed liquid flows downward into the buffer tank. The gas in the buffer tank passes through the demister in the upper part of the tank to remove the liquid above 10 microns and then enters the vacuum compressor unit system as a gas source through the gas outlet;

[0019] 4) The gas-liquid mixture from the vacuum compressor unit system enters the square high-gravity separation swirl tube through the gas inlet of the high-gravity separation buffer system in the tangential direction. Under the action of centrifugal force, the denser substances are thrown to the outside, and the gas passes through the exhaust holes on the inside and is discharged. After passing through the coalescing separation packing, the large liquid droplets in the gas coalesce again. Then, through the fine separation demisting component, the micron-sized liquid droplets in the gas are separated. The separation accuracy is 105 microns, and the separation efficiency is ≥99%. The gas enters the gas inlet of the vacuum compressor unit system; the liquid is cooled by the glycol heat exchange coil provided at the lower part, enters the buffer area through the weir plate, and when the liquid level reaches the upper limit, it enters the sewage pipeline through the liquid outlet;

[0020] After the glycol is heated, it enters the flash tank for flash separation; the high-gravity separation buffer system is provided with a glycol heat exchange coil at the lower part to recover the heat of the lower liquid by glycol, and the liquid is sent to the sewage system for centralized treatment; the high-gravity separation buffer system is equipped with a thermometer, a pressure gauge, a liquid level gauge, and a safety valve. When the system exceeds the set pressure, the safety valve jumps to protect the safety of the system.

[0021] The present invention can have the following beneficial effects compared with the above-mentioned background technology:

[0022] 1) In the discharged gas cooling system of the triethylene glycol dehydration device of the present invention, the temperature of the regenerator discharged gas is reduced, a large amount of water vapor is condensed into liquid water, the operating load of the vacuum compressor unit system and the high-gravity separation buffer system is reduced, and more moisture is prevented from entering the fuel gas system to cause safety accidents such as burner flameout. At the same time, the heat of the discharged gas is recovered to heat the glycol solution, reducing fuel gas consumption and achieving energy-saving effects. The glycol solution also has the function of preventing the liquid water from freezing and blocking the pipeline in winter.

[0023] 2) In the vacuum compressor unit system of the triethylene glycol dehydration device of the present invention, the operating pressure of the regenerator is reduced, a higher triethylene glycol regeneration concentration than the conventional process is obtained, up to 99.9% at most, and the dew point depression can reach 70°C, improving the dehydration effect of the device; the stripping gas is cancelled, reducing the consumption of natural gas; while ensuring the dehydration effect, the heating temperature of triethylene glycol can be reduced by 10 - 40°C, avoiding the decomposition of triethylene glycol when the local temperature of the furnace tube is too high, saving fuel, reducing energy consumption, and avoiding environmental pollution; the vacuum compressor unit system also pressurizes the discharged gas (liquid) to 110 - 400 kPa(A), enabling it to enter the subsequent corresponding system for recovery treatment without pollutant emissions.

[0024] 3) In the high-gravity separation buffer system of the triethylene glycol dehydration device of the present invention, the gas and liquid are fully separated, and the recovered gas is used as fuel gas; the high-gravity separation buffer system is provided with a liquid-phase coil heat exchanger at the lower part to recover the heat of the lower liquid by glycol, and at the same time, it can prevent the sewage from freezing in winter. The liquid is sent to the sewage system for centralized treatment, achieving zero emissions of hydrocarbons such as natural gas, avoiding environmental pollution, and eliminating potential safety hazards.

[0025] 4) The present invention is applicable to the dehydration of gases such as natural gas, coalbed methane, associated gas, shale gas, and coal-to-natural gas in oil and gas fields using triethylene glycol. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. Figure 1 is a conventional triethylene glycol dehydration device and process flow;

[0027] FIG. Figure 2 is the triethylene glycol dehydration device and process flow of the present invention;

[0028] FIG. Figure 3 is a schematic structural diagram of the exhaust gas cooling system of the present invention;

[0029] FIG. Figure 4 is FIG. Figure 3 a partially enlarged view of IV;

[0030] FIG. Figure 5 is a schematic structural diagram of the vacuum compressor unit system of the present invention;

[0031] FIG. Figure 6 is a schematic structural diagram of the high-gravity separation buffer system of the present invention;

[0032] FIG. Figure 7 is FIG. Figure 5 a partially enlarged view of V.

[0033] In the figure: 1 absorption tower; 2 glycol pump; 3, condenser at the top of the regeneration tower; 4, flash tank; 5, mechanical filter; 6, activated carbon filter; 7, glycol lean / rich liquid heat exchanger; 8, regeneration tower; 9, reboiler; 10, burner; 11, glycol lean liquid buffer tank; 12, gas / glycol heat exchanger; 13, off-gas cooling system; 14, vacuum compression unit system; 15, high-gravity separation buffer system; 16, off-gas inlet; 17, glycol outlet; 18, air outlet; 19, cooling outer tube; 20, outer fin; 21, cooling inner tube; 22, inner fin; 23, outer fin insulation shell; 24, air damper; 25, gas outlet A; 26, demister; 27, thermometer; 28, vacuum pressure gauge; 29, liquid level gauge; 30, liquid outlet A; 31, buffer tank; 32, tank insulation shell; 33, glycol inlet A; 34, gas inlet; 35, gas outlet B; 36, driving gas outlet; 37, driving gas inlet; 38, speed control valve; 39, commutation module; 40, commutation valve A; 41, commutation valve B; 42, power cylinder; 43, power piston; 44, piston rod; 45, boosting piston; 46, boosting cylinder; 47, air make-up port; 48, air make-up valve; 49, vacuum pressure transmitter; 50, control system; 51, gas-liquid inlet; 52, square high-gravity separation swirler; 53, exhaust hole; 54, coalescence separation packing; 55, inclined plate; 56, baffle plate; 57, glycol heat exchange coil; 58, glycol inlet; 59, glycol outlet A; 60, thermometer; 61, pressure gauge; 62, tank body; 63, fine separation demister assembly; 64, gas outlet; 65, back pressure valve; 66, weir plate; 67, liquid level gauge A; 68, liquid outlet; 69, vacuum pressure transmitter A; 70, gas inlet pipeline; 71, intake cavity; 72, electric push rod; 73, liquid intake cavity; 74, annular space; 75, expansion pipe; 76, mixed liquid outlet; 77, high-pressure liquid inlet; 78, boosting pump; 79, valve; 80, liquid inlet; 81, skid base; 101, wet gas inlet pipeline; 102, dry gas outlet pipeline; 103, glycol rich liquid pipeline; 104, glycol lean liquid pipeline; 105, regeneration tower top off-gas pipeline; 106, high-pressure fuel gas pipeline; 107, stripping gas pipeline; 108, sewage pipeline; 109, low-pressure fuel gas pipeline. Detailed implementation manners

[0034] The present invention will be further described below in conjunction with the drawings and embodiments, but the content of the present invention is not limited to the following embodiments.

[0035] As Figure 2As shown in the figure, an energy-saving and environment-friendly triethylene glycol dehydration device includes an absorption tower 1, an exhaust gas cooling system 13, a vacuum compression unit system 14, and a high gravity separation and buffering system 15. The rich triethylene glycol liquid pipeline 103 at the bottom of the absorption tower 1 is connected to the condenser 3 at the top of the regenerator through a triethylene glycol pump 2. The triethylene glycol solution pipeline after heat exchange at the top of the condenser 3 at the top of the regenerator is connected to the exhaust gas cooling system 13 and the high gravity separation and buffering system 15. The triethylene glycol outlet A59 of the high gravity separation and buffering system 15 is connected to a flash tank 4 through a rich triethylene glycol liquid pipeline. The bottom pipeline of the flash tank 4 is connected to a mechanical filter 5, an activated carbon filter 6, a triethylene glycol lean / rich liquid heat exchanger 7, a regenerator 8, a reboiler 9, and a triethylene glycol lean liquid buffer tank 11. The reboiler 9 is connected to a burner 10. The triethylene glycol lean liquid pipeline 104 at the bottom of the triethylene glycol lean liquid buffer tank 11 is connected to the side pipeline at the top of the absorption tower 1 through the triethylene glycol lean / rich liquid heat exchanger 7, the triethylene glycol pump 2, and a gas / triethylene glycol heat exchanger 12. The bottom of the gas / triethylene glycol heat exchanger 12 is connected to a dry gas outlet pipeline 102. The exhaust gas pipeline 105 at the top of the regenerator is connected to the exhaust gas inlet 16 at the top of the exhaust gas cooling system 13. The gas outlet A25 of the exhaust gas cooling system 13 is connected to the gas inlet pipeline 70 of the vacuum compression unit system 14.

[0036] As Figure 3 , 4 shown in the figure, the exhaust gas cooling system 13 has five interfaces. Its triethylene glycol inlet A33 is connected to the outlet of the condenser 3 at the top of the regenerator. The gas outlet A25 is connected to the gas inlet pipeline 70 of the vacuum compression unit system 14. The exhaust gas inlet 16 is connected to the exhaust gas pipeline 105 at the top of the regenerator. The triethylene glycol outlet 17 is connected to the lower triethylene glycol inlet 58 of the high gravity separation and buffering system 15. The liquid outlet A30 is connected to a sewage pipeline 108.

[0037] The exhaust gas cooling system 13 includes a cooling outer pipe 19, a cooling inner pipe 21, and a buffer tank 31; the cooling inner pipe 21 is installed in the center of the cooling outer pipe 19; the top opening of the cooling outer pipe 19 is the exhaust gas inlet 16; the outer wall of the cooling outer pipe 19 is welded with spiral metal outer fins 20 at a 45° inclination angle, and heat dissipation cooling is achieved through air convection; the top of the cooling inner pipe 21 passes through the open end of the elbow on the outer wall of the cooling outer pipe 19 to be the glycol outlet 17; spiral metal inner fins 22 at a 45° inclination angle are welded in the middle and upper parts of the outer wall of the cooling inner pipe 21, and a weir plate is provided on the upper part of the inner fins 22. The fins can increase the heat transfer area and improve the heat transfer effect; the medium in the cooling inner pipe 21 is a glycol solution; an outer fin heat preservation shell 23 is arranged outside the outer fins 20, and the outer fin heat preservation shell 23 can be divided into 3 sections and installed respectively at temperatures of 0°C, -10°C, and -20°C; the distance between the outer fin heat preservation shell 23 and the outer edge of the outer fins 20 is adjustable. The outer fin heat preservation shell 23, the outer fins, and the cooling outer pipe form a spiral channel. An air outlet 18 is provided at the top of the outer fin heat preservation shell 23. Under the action of natural wind force, a negative pressure suction force (chimney effect) is generated. During the process of air rising in the channel, heat exchange occurs between the air and the exhaust gas through the outer fins and the cooling outer pipe. The air is heated, its temperature increases, and its density becomes smaller, making it easier to rise; a damper 24 is provided below the outer fin heat preservation shell 23. A thermometer 27 is arranged inside the cooling outer pipe 19. When the temperature of the exhaust gas is lower than 5°C, the damper is automatically or manually adjusted to control the cold air flow and prevent the exhaust gas from freezing and blocking; the lower ends of the cooling outer pipe 19 and the cooling inner pipe 21 pass through the center of the top of the buffer tank 31 and penetrate into the buffer tank 31. A tank body heat preservation shell 32 is arranged outside the buffer tank 31; a liquid outlet A30 is opened at the bottom of the buffer tank 31, and the open end of the elbow where the bottom of the cooling inner pipe 21 passes through the outer wall of the buffer tank 31 is the glycol inlet A33; a vacuum pressure gauge 28 and a liquid level gauge 29 are connected to the buffer tank 31; a demister 26 is horizontally arranged at the bottom of the cooling outer pipe 19 inside the buffer tank 31; a gas outlet A25 is opened at the upper part of the buffer tank 31, and the gas outlet A25 is located above the demister 26; the glycol outlet 17 is connected to the lower glycol inlet 58 of the high gravity separation buffer system 15; the gas outlet A25 is connected to the gas inlet pipeline 70 of the vacuum compression unit system 14.

[0038] As Figure 5 , Figure 7 shown, the vacuum compression unit system 14 has 7 interfaces: the gas inlet 34 is connected to the gas outlet 64 of the high gravity separation buffer system 15, the gas outlet B35 is connected to the low-pressure fuel gas pipeline 109, the drive gas inlet 37 is connected to the high-pressure fuel gas pipeline 106, and the drive gas outlet 36 is connected to the low-pressure fuel gas pipeline 109; the gas inlet pipeline 70 is connected to the gas outlet A25 of the exhaust gas cooling system 13, the mixed liquid outlet 76 is connected to the gas-liquid inlet 51 of the high gravity separation buffer system 15, and the liquid inlet 80 is connected to the liquid outlet 68 of the high gravity separation buffer system 15.

[0039] The vacuum compression unit system 14 includes a booster pump 78 and a booster cylinder 46. One end of the booster pump 78 is connected to a liquid inlet 80 through a valve 79, and the other end is connected to a liquid inlet cavity 73 through a high-pressure liquid inlet 77. The right inner wall of the liquid inlet cavity 73 has a hyperbolic structure and is connected to the small-diameter end of an expansion pipe 75. The left side of the liquid inlet cavity 73 is connected to an air inlet cavity 71 through a sealing ring. The right side of the air inlet cavity 71 has a nozzle with a contraction angle of 8-15°, and the space between the right side of the air inlet cavity 71 and the liquid inlet cavity 73 is an annular gap space 74. The upper left side of the air inlet cavity 71 is connected to an electric push rod 72, and the middle left side is connected to a gas inlet pipeline 70 through a sealing ring. A vacuum pressure transmitter A 69 is connected to the left port of the gas inlet pipeline 70. The electric push rod 72 is fixed on the liquid inlet cavity 73 and the expansion pipe 75. The expansion angle of the expansion pipe 75 is 6-10°, and its length is 3-8 times the diameter of its small opening. The large-diameter end of the expansion pipe 75 is connected to a mixed liquid outlet 76. The booster pump 78 and the valve 79 are fixed on a skid base 81. On the left and right sides of the outer end of the cylinder body of the booster cylinder 46, pipelines are respectively connected. There is an air supplement port 47 on the upper side of the left pipeline, and the outlet of the left pipeline is a gas inlet 34. The air supplement port 47 is connected to a gas outlet B 35 through a vacuum pressure transmitter 49 and an air supplement valve 48. A gas outlet B 35 is opened on the right pipeline of the booster cylinder 46. The booster cylinder 46 is communicated with the gas inlet 34 and the gas outlet B 35 respectively through one-way valves. The booster piston 45 located inside the booster cylinder 46 is connected to the power piston 43 located inside the power cylinder 42 through a piston rod 44. A reversing valve A 40 and a reversing valve B 41 are arranged on the left and right sides inside the cylinder body of the power cylinder 42. The left side of the cylinder body of the power cylinder 42 is connected to two pipeline ends, which are a driving gas inlet 37 and a driving gas outlet 36 respectively. A speed regulating valve 38 is connected to the pipeline of the driving gas inlet 37. The power cylinder 42 is communicated with the driving gas inlet 37 through a one-way valve and the speed regulating valve 38, and the power cylinder 42 is communicated with the driving gas outlet 36 through a one-way valve. The reversing valve A 40 and the reversing valve B 41 are respectively communicated with the driving gas inlet 37 and the driving gas outlet 36 through a reversing module 39. The control system 50 is connected to the speed regulating valve 38, the air supplement valve 48, the vacuum pressure transmitter 49, the vacuum pressure transmitter A 69, the electric push rod 72, and the booster pump 78 through cables.

[0040] The vacuum compression unit system 14 can also be a single-stage or multi-stage vacuum compression unit composed of various types such as reciprocating, screw, Roots, slide valve, liquid ring, rotary vane, synchronous rotation, etc. mechanical types and jet vacuum / compression pumps, etc., which reduce the pressure at the inlet and increase the pressure at the outlet; in particular (including but not limited to), the vacuum compression pump described in the present invention that uses high-pressure liquid (or gas) as a power source to suck vacuum at the inlet, inhale exhaust gas (or gas-liquid mixture) and increase the pressure. The present invention takes two-stage vacuum compression as an example, and other single-stage or multi-stage vacuum compressions can be used to replace the two-stage vacuum compression of the present invention.

[0041] Such as Figure 6As shown in the figure, the supergravity separation buffer system 15 has five interfaces. The gas-liquid inlet 51 is connected to the mixed liquid outlet 76 of the vacuum compression unit system 14; the gas outlet 64 is connected to the gas inlet 34 of the vacuum compression unit system 14; the liquid outlet 68 is connected to the sewage pipeline 108 on one hand and the liquid inlet 80 of the vacuum compression unit system 14 on the other hand; the lower glycol inlet 58 is connected to the glycol outlet 17 of the discharge gas cooling system; the glycol outlet A59 is connected to the glycol inlet pipeline 103 of the flash tank 4;

[0042] The supergravity separation buffer system 15 includes a tank body 62. The upper right end of the tank body 62 is connected to the main body of the gas-liquid separation section. The upper part of the separation section main body is connected with a gas-liquid inlet 51. The gas-liquid inlet 51 is connected to a square gravity separation swirl tube 52. A number of exhaust holes 53 are distributed on the inner wall of the square gravity separation swirl tube 52; the coalescing separation packing 54 is circumferentially arranged on the inner wall of the bottom of the separation section main body; several inclined plates 55 at an angle of 70 - 85° with the horizontal direction are arranged in parallel below the coalescing separation packing 54 to slow down the rotation speed of the upper swirling liquid and prevent the impact on the liquid level in the lower tank body; a fine separation and demisting assembly 63 is installed at the left end inside the tank body 62. A gas outlet 64 is opened on the tank body corresponding to the fine separation and demisting assembly 63. The gas outlet 64 is connected to a back pressure valve 65. A liquid outlet 68 is opened on the tank body below the gas outlet 64. The liquid outlet 68 is connected to the station sewage pipeline 108. A glycol inlet 58 and a glycol outlet A59 are arranged at the lower right end of the tank body 62; a weir plate 66 is vertically arranged on the tank body below the fine separation and demisting assembly 63; a glycol heat exchange coil 57 is installed at the lower part of the tank body on the right side of the weir plate 66. A baffle plate 56 is arranged in the middle of the glycol heat exchange coil 57; a liquid level gauge A67 is installed outside the tank body; a thermometer 60 and a pressure gauge 61 are connected to the upper part of the tank body.

[0043] The process method for dehydration using an energy-saving and environment-friendly triethylene glycol dehydration device is as follows:

[0044] 1) The gas to be dried (such as natural gas, coalbed methane, associated gas, shale gas, and coal-to-natural gas) enters the absorption tower 1 from the lower part through the wet gas inlet pipeline 101, and flows upward layer by layer through the trays (or packing) in the absorption tower, countercurrently contacting the glycol solution flowing downward from the top of the absorption tower 1. The moisture in the gas is absorbed by the glycol solution, and then the gas exchanges heat with the glycol solution in the gas / glycol heat exchanger 12 and leaves the device. The glycol solution that has absorbed moisture enters the glycol pump 2 from the lower part of the absorption tower 1 to provide power for the glycol pump, enters the top condenser 3 of the regenerator, and the heat-exchanged glycol solution sequentially enters the off-gas cooling system 13 and the high-gravity separation buffer system 15 for heat exchange and temperature increase, and then enters the flash tank 4. The gas separated in the flash tank 4 is used as fuel gas, and the separated glycol solution sequentially enters the mechanical filter 5 and the activated carbon filter 6 to filter and separate the impurities therein, and then enters the glycol lean / rich solution heat exchanger 7. After heat exchange, it enters the regenerator 8 and the reboiler 9. The glycol solution is heated to 160 - 200 °C by the burner in the reboiler and regenerated by combining with the vacuum generated by the vacuum compression unit system 14; at this time, the regeneration concentration is 99 - 99.9%; the regenerated glycol solution enters the glycol lean solution buffer tank 11 to dissipate heat and be stored, and then enters the glycol lean / rich solution heat exchanger 7. After heat exchange and temperature reduction, it is pressurized by the glycol pump 2, and then enters the gas / glycol heat exchanger 12. After heat exchange and temperature reduction, it enters the absorption tower 1 from the side pipeline at the top for cyclic dehydration. To improve the dehydration effect, the off-gas containing moisture and some hydrocarbons enters the off-gas cooling system 13, the vacuum compression unit system 14, and the high-gravity separation buffer system 15 in sequence at the top of the regenerator 8. The off-gas from the regenerator is condensed, cooled, pressurized, and gas-liquid separated. The gas enters the fuel gas system and the liquid enters the sewage system.

[0045] 2) The glycol solution after heat exchange through the top condenser 3 of the regeneration tower enters the discharge gas cooling system 13 through the bottom glycol inlet A33 and ascends in the cooling inner pipe. The discharge gas from the regeneration tower 8 enters the discharge gas cooling system 13 from the top and descends. The outer wall of the cooling outer pipe 19 is welded with spiral metal fins at a 45° inclination angle, and it is cooled by air convection heat dissipation. A cooling inner pipe is arranged inside the cooling outer pipe, and the outer wall of the cooling inner pipe is welded with spiral metal fins at a 45° inclination angle. A weir plate is provided above the fins. The fins can increase the heat transfer area and improve the heat transfer effect. The medium in the cooling inner pipe is the glycol solution, and the glycol solution is used to cool the discharge gas at normal temperature. Low-boiling substances such as water vapor in it are condensed into liquids by the low-temperature air and glycol, and flow downward on the side close to the cooling inner pipe in the V-shaped groove formed by the cooling inner pipe and the inner fins. Under the action of centrifugal force, the liquid with a greater density will tend to the outer side more. The weir plate is arranged along the upper edge of the inner fins to prevent the liquid from being thrown onto the cooling outer pipe. Since the temperature of the incoming glycol liquid is above 20°C, it can be used to cool the discharge gas at normal temperature and can also heat the discharge gas that has been overly cooled by the outer pipe air in extremely cold winter conditions to prevent the water in the discharge gas from freezing and blocking. After the glycol solution recovers the heat of the discharge gas from the regeneration tower, its temperature is increased from 20 - 50°C to 40 - 70°C, and at the same time, the temperature of the discharge gas is decreased from 90 - 100°C to 40 - 80°C. The heated glycol solution enters the rotating packed bed separation and buffer system 15 as a heat source through the glycol outlet 17 and the glycol inlet 58 pipeline;

[0046] The discharge gas cooling system is provided with 3 sections of outer fin insulation shells, which are installed respectively when the temperature is 0°C, -10°C, -20°C (no installation is required when the temperature is above 0°C). The distance between the insulation shell and the outer edge of the outer fins is adjustable. The outer fin insulation shell, the outer fins, and the cooling outer pipe form a spiral channel, and an air outlet 18 is provided at a high place. Under the action of natural wind force, a negative pressure suction force (chimney effect) is generated. During the upward process of the air in the channel, it exchanges heat with the discharge gas through the outer fins and the cooling outer pipe. The air is heated, its temperature is increased, and its density becomes smaller, making it easier to rise. A damper is provided below the channel, and a thermometer is arranged inside the cooling outer pipe. When the temperature of the discharge gas is lower than 5°C, the damper is automatically or manually adjusted to control the cold air flow rate to prevent the discharge gas from freezing and blocking.

[0047] The condensed liquid flows downward into the buffer tank. When the liquid level reaches the upper limit, the valve (or pump) is automatically or manually started to discharge the liquid. The buffer tank is externally covered with an insulation shell; the gas in the buffer tank passes through the demister in the upper part of the tank to remove liquid above 10 microns and then enters the vacuum compression unit system 14 as a gas source through the gas outlet A25.

[0048] 3) The gas from the gas outlet A25 of the exhaust gas cooling system 13 enters the vacuum compressor unit system 14 through the gas inlet pipeline 70 as the gas source; after the vacuum compressor unit system 14 boosts the liquid provided by the liquid outlet 68 of the supergravity separation buffer system 15 to 0.3 - 3 MPa through the booster pump 78, it enters from the liquid inlet cavity and passes through the annular space formed by the right cavity of the hyperbola with a contraction angle of 120° and the nozzle with a contraction angle of 8 - 15° on the right side of the air inlet cavity 71 at high speed. After entraining and mixing with the gas source, it enters the expansion pipe 75 with an expansion angle of 6 - 10°. The speed decreases, the kinetic energy is converted into pressure energy, and the pressure is increased to 110 - 400 kPa(A) and enters the gas-liquid inlet 51 of the supergravity separation buffer system 15 through the mixed liquid outlet 76. The air inlet cavity 71 can be driven to move back and forth by the electric push rod 72 to adjust the cross-sectional size of the annular space and change the flow rate of the high-pressure liquid, so as to adjust the vacuum degree of the suction port to 10 - 100 kPa(A). Using this mixer can suck in liquid, and a small amount of liquid can enter the liquid ring or synchronous rotary vacuum compressor unit, etc.

[0049] High-pressure gas with a pressure of 0.2 - 5.0 MPa from the high-pressure fuel gas pipeline 106 enters the right side of the power piston 43 in the power cylinder 42 through the speed control valve 38 at the driving gas inlet 37 of the vacuum compression unit system 14, pushing the power piston 43 to move leftward. The power piston 43 pushes the booster piston 45 to move leftward through the piston rod 44. The gas from the gas outlet 64 of the supergravity separation buffer system 15 is sucked into the right side of the booster piston 45 in the booster cylinder 46 through the gas inlet 34. The front end of the gas inlet 34 is sucked into a vacuum, and the front-end pressure is controlled at 10 - 100 kPa(A) through the control system 50, the vacuum pressure transmitter 49, and the speed control valve 38. At the same time, the gas on the left side of the booster piston 45 in the booster cylinder 46 is pressurized to 110 - 400 kPa(A) and then leaves through the gas outlet B35 and enters the low-pressure fuel gas pipeline 109. When the power piston 43 moves to the left side of the power cylinder 42, it pushes the directional control valve A40 to change direction through the reversing module 39. The driving gas on the right side of the power piston 43 in the power cylinder 42 is discharged into the low-pressure fuel gas pipeline 109 through the driving gas outlet 36. At the same time, the high-pressure gas enters the left side of the power piston 43 in the power cylinder 42 through the driving gas inlet 37, pushing the power piston 43 to move rightward. The power piston 43 pushes the booster piston 45 to move rightward through the piston rod 44. The gas is sucked into the left side of the booster piston 45 in the booster cylinder 46 through the gas inlet 34. The front end of the gas inlet 34 is sucked into a vacuum, and the front-end pressure is controlled at 10 - 100 kPa(A) through the control system 50, the vacuum pressure transmitter 49, and the speed control valve 38. At the same time, the gas on the right side of the booster piston 45 in the booster cylinder 46 is pressurized to 110 - 400 kPa(A) and then leaves. When the power piston 43 moves to the right side of the power cylinder 42, it pushes the directional control valve B41 to change direction through the reversing module 39, and this cycle repeats. When the front-end pressure of the gas inlet 34 is lower than the set pressure, the control system 50 opens the air replenishing valve 48 to replenish air. The driving gas can be high-pressure natural gas or compressed air. After being driven by high-pressure natural gas, it can be recovered as low-pressure fuel gas, and the compressed air is directly vented.

[0050] The vacuum compression unit system 14 is connected to the regenerator top discharge gas pipeline 105 through the discharge gas cooling system 13, creating a vacuum environment inside the regenerator with the pressure controlled at 10 - 100 kPa(A). The operating temperature of the reboiler 9 is controlled at 160 - 200 °C by adjusting the burner 10. At the same time, the gas outlet is pressurized to 110 - 400 kPa(A) and then enters the low-pressure fuel gas pipeline 109. The control system 50 adjusts the inlet and outlet pressures through the vacuum pressure transmitter 49, the vacuum pressure transmitter A69, the speed control valve 38, the air replenishing valve 48, the booster pump 78, and the electric push rod 72. The vacuum compression unit system 14 can achieve the purpose of reducing the pressure at the inlet and increasing the pressure at the outlet.

[0051] 4) A supergravity separation section is provided at the inlet of the supergravity separation buffer system 15. The gas-liquid mixture from the vacuum compressor unit system 14 enters the square supergravity separation coil 52 tangentially through the gas-liquid inlet 51. Under the action of centrifugal force, the denser substances are thrown to the outside, and the gas passes through the exhaust holes 53 on the coil on the inner side and is discharged. After passing through the coalescing separation packing 54, the large liquid droplets in the gas coalesce again, and then through the fine separation demisting component 63, the liquid droplets in the gas at the micron level are separated, with a separation accuracy of 1-5 microns and a separation efficiency of ≥99%. The gas enters the gas inlet 34 of the vacuum compressor unit system 14; the liquid is cooled by the glycol heat exchange coil 57 provided at the lower part, then enters the buffer zone through the weir plate 66, and when the liquid reaches the upper limit, it enters the sewage pipeline 108 through the liquid outlet 68; the separation factor of the supergravity separation buffer system 15 can reach 15-30g, which can effectively separate the gas-liquid mixture generated by the previous-stage vacuum compressor unit system, prevent cavitation of the booster pump for transporting the liquid, reduce the liquid water carried in the gas, and avoid potential hazards to the fuel gas system; a glycol heat exchange coil 57 is provided at the lower part of the supergravity separation buffer system 15 to recover the heat of the lower liquid by glycol, and at the same time, it has the function of preventing freezing in winter, and the liquid is sent to the sewage system for centralized treatment; the supergravity separation buffer system is equipped with a thermometer, a pressure gauge, a liquid level gauge, and a safety valve. When the system exceeds the set pressure, the safety valve trips to protect the safety of the system.

[0052] The natural gas treatment capacity of a purification plant is 100×10 4 Nm 3 / d, the pressure is 5.5 MPa, the temperature is 40 °C, containing saturated water, and it is required that the water dew point after dehydration is ≤ -15 °C. Using the conventional process (such as Figure 1 shown), the regeneration heating temperature of glycol is 200 °C, the regeneration concentration without stripping gas is 98.9%, and the circulation rate is 1600 kg / h. At this time, the water dew point is only 0.9 °C, which cannot meet the dehydration index requirements. Therefore, when using the conventional triethylene glycol dehydration process to meet the index requirements, stripping gas must be added, increasing energy consumption and pollution. After using the dehydration device of the present invention, there is no need to add stripping gas, the regeneration concentration of triethylene glycol reaches 99.7-99.8%, the water dew point after dehydration is -16—-19.4 °C, meeting the dehydration index requirements, the exhaust gas is recycled, there is no pollutant discharge, and the energy consumption is lower, 76-80% lower than the conventional process. The comparison of the on-site operation effect and energy consumption between the conventional process and the use of the present invention is shown in Table 1:

[0053] Table 1

[0054]

[0055] [Note 1] Calculated by converting the power generation of 3.3 kW per 1 Nm 3 of natural gas into natural gas flow

[0056] [Note 2] Energy consumption is calculated based on the total consumption of natural gas

[0057] The higher the regeneration concentration of triethylene glycol, the better the dehydration effect and the lower the water dew point. By using the device and process of the present invention, a higher regeneration concentration of triethylene glycol can be obtained at the same operating temperature, and the same regeneration concentration of triethylene glycol as that at a higher operating temperature of the conventional process can be obtained at a lower operating temperature, with lower energy consumption. The dew point depression of triethylene glycol dehydration with a concentration of 99.99% can reach 70°C. The regeneration concentration of triethylene glycol obtained after adjusting different operating pressures and temperatures is shown in Table 2.

[0058] Table 2

[0059]

[0060] [Note] The column with an operating pressure of 101 kPaA is the regeneration concentration of triethylene glycol in the conventional process, and the four columns with operating pressures of 80, 50,

[0061] 30, and 10 kPaA are the regeneration concentrations of triethylene glycol in the process of the present invention.

[0062] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Those of ordinary skill in the relevant technical field can make some changes or modifications to equivalent embodiments with equivalent changes without departing from the spirit and scope of the present invention. However, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention. In particular, the present invention takes secondary vacuum compression as an example, and other uses of primary or multi-stage vacuum compression also fall within the scope of the technical solution of the present invention.

Claims

1. An energy-saving and environment-friendly triethylene glycol dehydration device, comprising an absorption tower (1), wherein a pipeline at the bottom of the absorption tower (1) is connected to a condenser at the top of the regenerator through a glycol pump (2), and is characterized in that: The glycol solution pipeline after heat exchange at the top of the regeneration tower condenser (3) is connected to the exhaust gas cooling system (13) and the high gravity separation and buffering system (15); the pipeline of the glycol outlet A (59) of the high gravity separation and buffering system (15) is connected to the flash tank (4); the bottom pipeline of the flash tank (4) is connected to the filter, heat exchanger, regeneration tower (8), reboiler (9), and lean glycol buffer tank (11); the bottom pipeline of the lean glycol buffer tank (11) is connected to the side pipeline at the top of the absorption tower (1) through the gas / glycol heat exchanger (12); the top outlet pipeline of the regeneration tower (8) is connected to the top inlet pipeline of the exhaust gas cooling system (13); The exhaust gas cooling system (13) includes a cooling outer pipe (19), a cooling inner pipe (21), and a buffer tank (31); the cooling inner pipe (21) is installed in the center of the cooling outer pipe (19); the top opening of the cooling outer pipe (19) is the exhaust gas inlet (16); the outer wall of the cooling outer pipe (19) has outer fins (20); the top of the cooling inner pipe (21) passes through the elbow opening end of the outer wall of the cooling outer pipe (19) to be the glycol outlet (17); the middle and upper parts of the outer wall of the cooling inner pipe (21) have inner fins (22); the lower ends of the cooling outer pipe (19) and the cooling inner pipe (21) pass through the top center of the buffer tank (31) and penetrate into the buffer tank (31), and a tank body heat preservation shell (32) is arranged outside the buffer tank (31); a liquid outlet A (30) is opened at the bottom of the buffer tank, and the elbow opening end where the bottom of the cooling inner pipe (21) passes through the outer wall of the buffer tank (31) is the glycol inlet A (33); a gas outlet A (25) is opened at the upper part of the buffer tank (31); the glycol outlet (17) is connected to the lower glycol inlet (58) of the high gravity separation and buffering system (15); the gas outlet A (25) is connected to the gas inlet pipeline (70) of the vacuum compression unit system (14); The high gravity separation and buffering system (15) includes a tank body (62), the upper right end of the tank body (62) is connected to the main body of the gas-liquid separation section, the upper part of the separation section main body is connected with a gas-liquid inlet (51), the gas-liquid inlet (51) is connected to a square high gravity separation swirl tube, and a number of exhaust holes (53) are distributed on the inner wall of the square high gravity separation swirl tube (52); a fine separation and demisting component (63) is installed at the left end inside the tank body (62), a gas outlet (64) is opened on the tank body corresponding to the fine separation and demisting component (63), the gas outlet (64) is connected to a back pressure valve (65), and a liquid outlet (68) is opened on the tank body below the gas outlet (64); a glycol inlet (58) and a glycol outlet A (59) are arranged at the lower right end of the tank body (62); a glycol heat exchange coil (57) is installed at the lower right side of the tank body; The vacuum compression unit system (14) includes a booster pump (78) and a booster cylinder (46); one end of the booster pump (78) is connected to a liquid inlet (80) through a valve (79), and the other end is connected to a liquid inlet cavity (73) through a high-pressure liquid inlet (77); the right inner wall of the liquid inlet cavity (73) has a hyperbolic structure and is connected to the small-diameter end of an expansion pipe (75), and the left side of the liquid inlet cavity (73) is connected to an air inlet cavity (71) through a sealing ring; the right port of the air inlet cavity (71) extends into the liquid inlet cavity (73), and the right port of the air inlet cavity (71) is a nozzle with a contraction angle of 8-15°, and the space between it and the right side of the liquid inlet cavity (73) is an annular gap space (74); the upper left side of the air inlet cavity (71) is connected to an electric push rod (72), and the middle left side is connected to a gas inlet pipeline (70) through a sealing ring; a vacuum pressure transmitter A (69) is connected to the left port of the gas inlet pipeline (70); the electric push rod (72) is fixed on the liquid inlet cavity (73) and the expansion pipe (75); the expansion angle of the expansion pipe (75) is 6-10° and its length is 3-8 times the small-diameter of its small end, and the large-diameter end of the expansion pipe (75) is connected to a mixed liquid outlet (76); the booster pump (78) and the valve (79) are fixed on a skid base (81). Both the left and right sides of the outer end of the cylinder body of the booster cylinder (46) are connected with pipelines. There is an air supplement port (47) on the upper side of the left pipeline, and the outlet of the left pipeline is a gas inlet (34). A gas outlet B (35) is opened on the right pipeline; the air supplement port (47) is connected to the gas outlet B (35) through a vacuum pressure transmitter (49) and an air supplement valve (48); the booster cylinder (46) is respectively communicated with the gas inlet (34) and the gas outlet B (35) through one-way valves; a booster piston (45) located inside the booster cylinder (46) is connected to a power piston (43) located inside a power cylinder (42) through a piston rod (44); the left side of the cylinder body of the power cylinder (42) is connected with two pipeline ends which are respectively a driving gas inlet (37) and a driving gas outlet (36), and a speed regulating valve (38) is connected to the pipeline of the driving gas inlet (37); the power cylinder (42) is communicated with the driving gas inlet (37) through a one-way valve and the speed regulating valve (38), and the power cylinder (42) is communicated with the driving gas outlet (36) through a one-way valve.

2. The energy-saving and environment-friendly triethylene glycol dehydration device according to claim 1, characterized in that: Inside the buffer tank (31), a demister (26) is horizontally arranged at the bottom of the internal cooling outer pipe (19); the gas outlet A (25) is located above the demister (26); the buffer tank (31) is connected with a vacuum pressure gauge (28) and a liquid level gauge (29); the outer fins (20) and the inner fins (22) are respectively spiral metal fins; the inclination angles of the outer fins (20) and the inner fins (22) are both 45º; a weir plate is provided at the upper part of the inner fins (22); three sections of outer fin heat preservation shells (23) are arranged outside the outer fins (20); the distance between the outer fin heat preservation shell (23) and the outer edge of the outer fins (20) is adjustable, and the outer fin heat preservation shell (23), the outer fins and the cooling outer pipe form a spiral channel, and an air outlet (18) is provided at the top of the outer fin heat preservation shell (23); a damper (24) is provided below the outer fin heat preservation shell (23), and a thermometer (27) is arranged inside the cooling outer pipe (19).

3. The energy-saving and environment-friendly triethylene glycol dehydration device according to claim 2, characterized in that: Inside the middle part of the glycol heat exchange coil (57) of the rotating packed bed separation buffer system (15), a baffle (56) is arranged; a weir plate (66) is vertically arranged on the lower part of the tank body of the fine separation demisting component (63); a liquid level gauge A (67) is installed outside the tank body (62); a thermometer (60) and a pressure gauge (61) are connected to the upper part of the tank body; the glycol heat exchange coil (57) is arranged at the lower part of the tank body on the right side of the weir plate (66).

4. An energy-saving and environment-friendly triethylene glycol dehydration device according to claim 3, characterized in that: On the inner wall of the bottom of the main body of the separation section of the rotating packed bed separation buffer system (15), coalescing separation packing (54) is arranged circumferentially; several inclined plates (55) which are parallel to each other and form an angle of 70-85° with the horizontal direction are arranged below the coalescing separation packing (54).

5. An energy-saving and environment-friendly triethylene glycol dehydration device according to claim 4, characterized in that: On both sides of the power cylinder (42), a reversing valve A (40) and a reversing valve B (41) are installed. The reversing valve A (40) and the reversing valve B (41) are communicated with the driving gas inlet (37) and the driving gas outlet (36) through a reversing module (39); the control system (50) is respectively connected with a vacuum pressure transmitter (49), a speed regulating valve (38), a gas supplementing valve (48), a vacuum pressure transmitter A (69), a booster pump (78) and an electric push rod (72) through cables.

6. The energy-saving and environment-friendly triethylene glycol dehydration device according to claim 5, characterized in that: The vacuum compression unit system (14) has 7 interfaces: the gas inlet (34) is connected with the gas outlet (64) of the rotating packed bed separation buffer system (15), the gas outlet B (35) is connected with the low-pressure fuel gas pipeline (109), the driving gas inlet (37) is connected with the high-pressure fuel gas pipeline (106), and the driving gas outlet (36) is connected with the low-pressure fuel gas pipeline (109); the gas inlet pipeline (70) is connected with the gas outlet A (25) of the exhaust gas cooling system (13), the mixed liquid outlet (76) is connected with the gas-liquid inlet (51) of the rotating packed bed separation buffer system (15), and the liquid inlet (80) is connected with the liquid outlet (68) of the rotating packed bed separation buffer system (15); The described exhaust gas cooling system (13) has five interfaces. Its glycol inlet A (33) is connected to the outlet of the top condenser of the regenerator (3); the gas outlet A (25) is connected to the gas inlet pipeline (70) of the vacuum compressor unit system (14); the exhaust gas inlet (16) is connected to the exhaust gas outlet of the regenerator (8); the glycol outlet (17) is connected to the lower glycol inlet (58) of the high-gravity separation and buffer system (15); the liquid outlet A (30) is connected to the sewage pipeline (108). The described high-gravity separation and buffer system (15) has five interfaces. The gas-liquid inlet (51) is connected to the mixed liquid outlet (76) of the vacuum compressor unit system (14); the gas outlet (64) is connected to the gas inlet (34) of the vacuum compressor unit system (14); the liquid outlet (68) is connected to the sewage pipeline (108) on one hand and the liquid inlet (80) of the vacuum compressor unit system (14) on the other hand; the lower glycol inlet (58) is connected to the glycol outlet (17) of the exhaust gas cooling system; the glycol outlet A (59) is connected to the glycol inlet pipeline (103) of the flash tank (4).

7. A triethylene glycol dehydration process using the device according to any one of claims 5-6, characterized in that: It includes the following steps: 1) The gas to be dried enters the lower part of the absorption tower. In the absorption tower, it contacts countercurrently with the glycol solution flowing downward from the top of the absorption tower from bottom to top. The moisture in the gas is absorbed by the glycol solution and then enters the gas / glycol heat exchanger (12) to exchange heat with the glycol solution and then leaves the device; the glycol solution that has absorbed moisture enters the top condenser of the regenerator (3) through the glycol pump (2) from the lower part of the absorption tower. The heat-exchanged glycol solution sequentially enters the exhaust gas cooling system (13) and the high-gravity separation and buffer system (15) for heat exchange and temperature rise and then enters the flash tank (4) for flash separation; the exhaust gas containing moisture and part of hydrocarbons enters the exhaust gas cooling system (13), the vacuum compressor unit system (14), and the high-gravity separation and buffer system (15) in sequence at the top of the regenerator; the vacuum compressor unit system is connected to the top pipeline of the regenerator (8) through the exhaust gas cooling system to create a vacuum environment inside the regenerator, with the pressure controlled at 10 - 100 kPa(A). Adjust the burner (10) to control the operating temperature of the reboiler (9) at 160 - 200 °C, and at the same time increase the pressure of the gas outlet to 110 - 400 kPa(A); the exhaust gas from the regenerator is condensed, cooled, pressurized, and gas-liquid separated. The gas enters the fuel gas system and the liquid enters the sewage system. 2) The glycol solution separated in the flash tank enters the filter to filter out the impurities therein and then enters the glycol lean / rich liquid heat exchanger. After heat exchange, the glycol solution is heated to 160 - 200 °C by the burner (10) in the reboiler (9) and regenerated in combination with the vacuum generated by the vacuum compressor unit system (14); the regenerated glycol solution enters the glycol lean liquid buffer tank (11) to dissipate heat and be stored, and then after heat exchange and cooling, it is pressurized by the glycol pump and enters the gas / glycol heat exchanger (12). After heat exchange and cooling, it enters the absorption tower (1) from the upper part for cyclic dehydration. 3) The glycol solution after heat exchange through the top condenser (3) of the regeneration tower enters the discharge gas cooling system (13) through the bottom glycol inlet A (33) and ascends in the cooling inner pipe. The discharge gas from the regeneration tower 8 enters the discharge gas cooling system (13) from the top and descends. The discharge gas spirally descends through the channel composed of the cooling outer pipe, the cooling inner pipe and the inner fins. The low-boiling substances such as water vapor therein are condensed into liquids by the low-temperature air and glycol and flow downward on the side close to the cooling inner pipe in the V-shaped groove formed by the cooling inner pipe and the inner fins. The glycol solution is used to cool the discharge gas at normal temperature. After the glycol solution recovers the heat of the discharge gas from the regeneration tower, its temperature rises from 20 - 50 °C to 40 - 70 °C, and at the same time, the temperature of the discharge gas drops from 90 - 100 °C to 40 - 80 °C. The heated glycol solution enters the rotating packed bed separation and buffering system through the pipeline of the glycol inlet (58) from the glycol outlet (17) as a heat source; The condensed liquid flows downward into the buffer tank (31). The gas in the buffer tank passes through the demister in the upper part of the tank to remove the liquid above 10 microns and then enters the vacuum compression unit system through the gas outlet A (25) as a gas source; 4) The gas-liquid mixture from the vacuum compression unit system (14) enters the square rotating packed bed separation pipe (52) of the rotating packed bed separation and buffering system (15) tangentially through the gas-liquid inlet (51). Under the action of centrifugal force, the denser substances are thrown to the outside, and the gas passes through the exhaust holes on the inside. After passing through the coalescing separation packing (54), the large liquid droplets in the gas coalesce again, and then through the fine separation demister assembly (63), the liquid droplets in the gas at the micron level are separated. The separation accuracy is 1 - 5 microns, and the separation efficiency is ≥99%. The gas enters the gas inlet (34) of the vacuum compression unit system. The liquid is cooled by the glycol heat exchange coil (57) provided at the lower part and then enters the buffer area through the weir plate (66). When the liquid level reaches the upper limit, it enters the sewage pipeline (108) through the liquid outlet (68); The glycol is heated and then enters the flash tank for flash separation; The rotating packed bed separation and buffering system (15) is provided with a glycol heat exchange coil (57) at the lower part to recover the heat of the lower liquid by glycol, and the liquid is sent to the sewage system for centralized treatment. The rotating packed bed separation and buffering system is equipped with a thermometer, a pressure gauge, a liquid level gauge and a safety valve. When the system exceeds the set pressure, the safety valve jumps to protect the safety of the system.

8. A triethylene glycol dehydration process according to claim 7, characterized in that: The exhaust gas from the gas outlet A (25) of the exhaust gas cooling system (13) enters the vacuum compressor unit system through the gas inlet pipeline (70) as the gas source; after the vacuum compressor unit system boosts the liquid provided by the liquid outlet (68) of the high-gravity separation buffer system (15) to 0.3 - 3 MPa through the booster pump (78), it enters from the liquid inlet cavity, and passes through the annular space formed by the cavity with a hyperbolic contraction angle of 120° and the nozzle with a contraction angle of 8 - 15° at high speed, entraining the gas source. The gas-liquid mixture enters the expansion pipe (75) with an expansion angle of 6 - 10° after passing through a straight pipe section with a length 3 - 5 times its diameter. The speed decreases, and the kinetic energy is converted into pressure energy. After the pressure increases, it enters the gas-liquid inlet (51) of the high-gravity separation buffer system (15). The intake cavity (71) can be driven to move back and forth by the electric push rod (72) to adjust the annular space of the high-pressure liquid, change the flow rate of the high-pressure liquid, and thus adjust the vacuum degree of the suction port; High-pressure gas with a pressure of 0.2 - 5.0 MPa from the high-pressure fuel gas pipeline (106) enters the right side of the power piston (43) in the power cylinder (42) through the speed control valve (38) at the driving gas inlet (37) of the vacuum compression unit system (14), pushing the power piston (43) to move leftward. The power piston (43) drives the booster piston (45) to move leftward through the piston rod (44). The gas from the gas outlet (64) of the supergravity separation and buffer system (15) is sucked into the right side of the booster piston (45) in the booster cylinder (46) through the gas inlet (34). The front end of the gas inlet (34) is sucked into a vacuum, and the front-end pressure is controlled at 10 - 100 kPa(A) through the control system (50), the vacuum pressure transmitter (49), and the speed control valve (38). At the same time, the gas-liquid mixture on the left side of the booster piston (45) in the booster cylinder (46) is pressurized to 110 - 400 kPa(A) and then leaves through the gas outlet B (35) and enters the low-pressure fuel gas pipeline (109). When the power piston (43) moves to the left side of the power cylinder (42), it drives the change-over valve A (40) to change direction through the change-over module (39). The driving gas on the right side of the power piston (43) in the power cylinder (42) is discharged to the low-pressure fuel gas pipeline (109) through the driving gas outlet (36). At the same time, the high-pressure gas enters the left side of the power piston (43) in the power cylinder (42) through the driving gas inlet (37), pushing the power piston (43) to move rightward. The power piston (43) drives the booster piston (45) to move rightward through the piston rod (44). The gas is sucked into the left side of the booster piston (45) in the booster cylinder (46) through the gas inlet (34). The front end of the gas inlet (34) is sucked into a vacuum, and the front-end pressure is controlled at 10 - 100 kPa(A) through the control system (50), the vacuum pressure transmitter (49), and the speed control valve (38). At the same time, the gas on the right side of the booster piston (45) in the booster cylinder (46) is pressurized to 110 - 400 kPa(A) and then leaves. When the power piston (43) moves to the right side of the power cylinder (42), it drives the change-over valve B (41) to change direction through the change-over module (39), and so on in a repeated cycle. When the front-end pressure of the gas inlet (34) is lower than the set pressure, the control system opens the air supply valve (48) to supply air. The driving gas can be high-pressure natural gas or compressed air. After being driven by high-pressure natural gas, it can be recovered as low-pressure fuel gas, and the compressed air is directly vented.

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