Tail gas recovery treatment device for triethylene glycol reboiler

Abstract

The utility model discloses a triethylene glycol reboiler tail gas recovery treatment device, which belongs to the technical field of triethylene glycol dehydration treatment and comprises a tail gas inlet pipeline, an emptying pipeline, a liquid discharge pipeline and a fuel gas pipeline. The head end and the tail end of the tail gas inlet pipeline are communicated with an exhaust port of the triethylene glycol reboiler and a gas inlet in the side wall of the gas-liquid separator respectively, the emptying pipeline is communicated with the tail gas inlet pipeline and the gas pipeline, the gas pipeline is communicated with an exhaust port in the top of the gas-liquid separator, and the liquid discharging pipeline is communicated with a liquid discharging port in the bottom of the gas-liquid separator. The device is simple in principle, convenient and easy to operate and low in cost, cooling, separation and recycling of the tail gas can be efficiently completed, environmental pollution caused by direct emission of the tail gas is avoided, the unpowered hood is additionally arranged above the combustion emptying device, and the treatment efficiency of the tail gas recycling device is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of gas storage reservoir gas production engineering, in particular to a tail gas recovery and treatment device for a triethylene glycol reboiler. Background Technique

[0002] During the gas production process of the gas storage reservoir, a certain amount of gaseous water and liquid water are usually carried, which not only causes serious corrosion problems in the gathering pipeline during the natural gas gathering process, but also if the content of gaseous water and liquid water carried in the natural gas produced from the gas storage reservoir is too high, it cannot meet the finished natural gas pipeline transportation standard. Therefore, natural gas dehydration is necessary.

[0003] The triethylene glycol dehydration device is one of the commonly used and relatively mature natural gas dehydration devices. This type of device utilizes the characteristics of triethylene glycol being easy to absorb water and having a high boiling point to suck out the water vapor in natural gas, so as to reduce the content of gaseous water and liquid water in the produced gas. After triethylene glycol sucks out the gaseous water and liquid water in natural gas, a supporting regeneration device for triethylene glycol is used to heat the rich triethylene glycol liquid, that is, the triethylene glycol liquid rich in gaseous water and liquid water, to separate water from triethylene glycol. The separated water vapor is the tail gas generated by the triethylene glycol regeneration device. This tail gas not only contains water vapor, but also contains a part of triethylene glycol, natural gas and other hydrocarbon gases. If directly discharged, it will cause environmental pollution and does not meet the requirements of energy conservation and environmental protection.

[0004] At present, the conventional triethylene glycol tail gas treatment device connects the triethylene glycol tail gas to a combustion furnace for incineration. Not only does the combustion furnace need to provide heat source, increasing energy consumption, but also the triethylene glycol in the triethylene glycol tail gas is difficult to recover, resulting in waste of triethylene glycol. Content of the Utility Model

[0005] The technical problem to be solved by the utility model is to provide a tail gas recovery and treatment device for a triethylene glycol reboiler, which can burn the combustibles in the triethylene glycol tail gas and efficiently recycle triethylene glycol. At the same time, by adding a non-powered negative pressure device such as a non-powered wind cap, the use efficiency of the triethylene glycol reboiler tail gas recovery and treatment device is greatly improved, and energy consumption is reduced.

[0006] In order to solve the above technical problems, the technical solution of the utility model is realized as follows:

[0007] A tail gas recovery and treatment device for a triethylene glycol reboiler, the tail gas recovery and treatment device includes a tail gas inlet pipeline, a liquid discharge pipeline and a gas supply pipeline. The head and tail ends of the tail gas inlet pipeline are respectively communicated with the exhaust port of the triethylene glycol reboiler and the intake port on the side wall of the gas-liquid separator. The gas supply pipeline is communicated with the exhaust port at the top of the gas-liquid separator, and the liquid discharge pipeline is communicated with the liquid discharge port at the bottom of the gas-liquid separator;

[0008] An exhaust gas inlet control valve, a variable frequency fan, a heat exchanger inlet control valve, a heat exchanger, and a gas-liquid separator inlet control valve are sequentially arranged on the exhaust gas inlet pipeline along the direction of exhaust gas transportation; among them, the variable frequency fan is used to control the pressure and flow rate of the gas on the exhaust gas inlet pipeline, the heat exchanger is used to condense the water vapor and triethylene glycol gas mixed in the exhaust gas, and the condensed gas-liquid mixture enters the gas-liquid separator for gas-liquid separation;

[0009] A burner inlet control valve, a flame arrester, a triethylene glycol regeneration burner, and a combustion vent are sequentially arranged on the gas pipeline along the direction of gas transportation. A non-powered wind cap connected to it is rotatably connected above the combustion vent; among them, the flame arrester is used to prevent the natural gas of the triethylene glycol regeneration burner from flowing back and generating combustion, and the triethylene glycol regeneration burner is used to burn and reuse the recovered natural gas. The gas generated during combustion is discharged through the combustion vent under the action of the non-powered wind cap;

[0010] A separator drain control valve, a filter, a lift pump inlet control valve, a lift pump, a drain manual valve, and a drain interface are sequentially arranged on the drain pipeline along the direction of liquid transportation; among them, the gas-liquid separator uses gravity to separate the mixed liquid of triethylene glycol and a small amount of water, and the lift pump is used to drive the mixed liquid to flow towards the drain interface.

[0011] As a preferred implementation manner of a triethylene glycol reboiler exhaust gas recovery and treatment device, the exhaust gas recovery and treatment device further includes a vent pipeline, and the vent pipeline is connected to the exhaust gas inlet pipeline and the gas pipeline.

[0012] As a preferred implementation manner of a triethylene glycol reboiler exhaust gas recovery and treatment device, the vent pipeline includes a vent pipeline A and a vent pipeline B. The vent pipeline A is connected to the exhaust gas inlet pipeline between the exhaust gas inlet control valve and the variable frequency fan, and the vent pipeline B is connected to the gas pipeline between the burner inlet control valve and the gas-liquid separator.

[0013] As a preferred implementation manner of a triethylene glycol reboiler exhaust gas recovery and treatment device, a reboiler vent control valve is arranged on the vent pipeline A, a separator vent control valve is arranged on the vent pipeline B, and a vent exhaust interface is jointly arranged at the ends of the vent pipeline A and the vent pipeline B.

[0014] As a preferred implementation manner of a triethylene glycol reboiler exhaust gas recovery and treatment device, a liquid level transmitter for detecting the liquid level height in the gas-liquid separator tank is further arranged on the inner side wall of the gas-liquid separator. The liquid level transmitter is electrically connected to the separator drain control valve and controls 20 - 80% of the volume of the gas-liquid separator tank through the separator drain control valve.

[0015] As a preferred embodiment of a tail gas recovery and treatment device for a triethylene glycol reboiler, the liquid level transmitter is also electrically connected to the liquid inlet control valve of the lift pump; wherein, the liquid level transmitter is used to monitor the liquid level in the gas-liquid separator tank. When the liquid level in the tank is higher than a certain value, the lift pump and the corresponding valves are automatically started to discharge the liquid, so as to always control the liquid level of the gas-liquid separator at 20%-80%, preventing the lift pump from starting and stopping frequently.

[0016] As a preferred embodiment of a tail gas recovery and treatment device for a triethylene glycol reboiler, the lift pump can drive the liquid in the liquid discharge pipeline to be transported from the gas-liquid separator to the liquid discharge interface.

[0017] As a preferred embodiment of a tail gas recovery and treatment device for a triethylene glycol reboiler, a data acquisition mechanism for detecting temperature is provided on the heat exchanger. The controller controls the temperature of the gas-liquid mixture at the outlet of the heat exchanger at 45-60°C according to the temperature signal detected by the data acquisition mechanism, ensuring the cooling effect of the gas-liquid separator on water vapor and avoiding freezing of condensed water due to too low temperature.

[0018] As a preferred embodiment of a tail gas recovery and treatment device for a triethylene glycol reboiler, at least one set of stop valves, at least one set of data acquisition mechanisms for detecting temperature, pressure or flow rate, and a controller are respectively connected to the triethylene glycol reboiler tail gas inlet pipeline, the vent pipeline, the liquid discharge pipeline, and the gas pipeline, wherein the controller is electrically connected to the data acquisition mechanism.

[0019] After adopting the above technical solutions, the beneficial effects of the present utility model are:

[0020] 1. The tail gas recovery device has a high degree of automation, can realize dehydration and recycling of triethylene glycol tail gas, save energy consumption, and reduce organic gas emissions;

[0021] 2. By setting a heat exchanger in the triethylene glycol tail gas inlet pipeline, the temperature can be controlled at 45-60°C according to the temperature signal detected by its data acquisition mechanism, and the data acquisition and control mechanism of the transmission mechanism can ensure the cooling effect of the gas-liquid separator on water vapor and avoid freezing of condensed water due to too low temperature;

[0022] 3. By setting a liquid level sensor in the gas-liquid separator, the liquid discharge control valve of the gas-liquid separator can be automatically controlled by the control mechanism, so that the liquid level is controlled at 20-80% of the tank volume, reducing the frequent start and stop of the lift pump and ensuring the continuous operation of the lift pump.

[0023] 4. By setting a power-free wind cap above the combustion vent, the overall utilization efficiency of the tail gas recovery device can be improved through the power-free negative pressure device, especially the combustion reuse efficiency in the triethylene glycol regeneration burner. The ejector and its supporting automatic control device are no longer used, simplifying the device process and reducing energy consumption. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic diagram of the operation of the tail gas purification and recovery device of the triethylene glycol reboiler in the first embodiment;

[0026] Figure 2 It is a schematic diagram of the operation of the tail gas purification and recovery device of the triethylene glycol reboiler in the second embodiment.

[0027] Markings in the figure: 1. Triethylene glycol reboiler; 2. Variable frequency fan; 3. Heat exchanger for cold treatment of tail gas; 4. Gas-liquid separator; 5. Vent exhaust interface; 6. Drainage interface; 7. Lift pump; 8. Filter; 9. Gas-liquid separator liquid level transmitter; 10. Triethylene glycol regeneration burner; 11. Combustion vent; 12. Power-free wind cap; 101. Tail gas inlet control valve; 102. Heat exchanger inlet control valve; 103. Gas-liquid separator inlet control valve; 104. Reboiler vent control valve; 105. Separator vent control valve; 106. Burner inlet control valve; 107. Flame arrester; 108. Drainage manual valve; 109. Lift pump inlet control valve; 110. Separator drainage control valve; 100. Tail gas inlet pipeline; 200. Vent pipeline; 300. Drainage pipeline; 400. Gas pipeline. Specific embodiments

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0029] First embodiment

[0030] Such as Figure 1As shown in the figure, a tail gas recovery and treatment device for a triethylene glycol reboiler. The tail gas recovery and treatment device includes a tail gas inlet pipeline 100, a vent pipeline 200, a drain pipeline 300, and a gas pipeline 400. The head and tail ends of the tail gas inlet pipeline 100 are respectively connected and communicated with the exhaust port of the triethylene glycol reboiler 1 and the air inlet of the side wall of the gas-liquid separator 4. The vent pipeline 200 is connected and communicated with the tail gas inlet pipeline 100 and the gas pipeline 400. The gas pipeline 400 is connected and communicated with the exhaust port at the top of the gas-liquid separator 4. The drain pipeline 300 is connected and communicated with the drain port at the bottom of the gas-liquid separator 4;

[0031] On the tail gas inlet pipeline 100, a tail gas inlet control valve 101, a variable frequency fan 2, a heat exchanger inlet control valve 102, a heat exchanger 3, and a gas-liquid separator inlet control valve 103 are sequentially arranged along the direction of tail gas transportation. Among them, the variable frequency fan 2 is used to control the pressure and flow rate of the gas on the tail gas inlet pipeline 100. The heat exchanger 3 is used to condense the water vapor and triethylene glycol gas mixed in the tail gas. The condensed gas-liquid mixture enters the gas-liquid separator 4 for gas-liquid separation;

[0032] The vent pipeline 200 includes a vent pipeline A and a vent pipeline B. The vent pipeline A is connected and communicated with the tail gas inlet pipeline 100 between the tail gas inlet control valve 101 and the variable frequency fan 2. The vent pipeline B is connected and communicated with the gas pipeline 400 between the burner air inlet control valve 106 and the gas-liquid separator 4. A reboiler vent control valve 104 is arranged on the vent pipeline A. A separator vent control valve 105 is arranged on the vent pipeline B. The tail ends of the vent pipeline A and the vent pipeline B are jointly provided with a vent exhaust interface 5;

[0033] On the gas pipeline 400, a burner air inlet control valve 106, a flame arrester 107, a triethylene glycol regeneration burner 10, and a combustion vent 11 are sequentially arranged along the direction of gas transportation. An unpowered wind cap 12 is rotatably connected above the combustion vent 11 and communicated with it. Among them, the flame arrester 107 is used to prevent the natural gas of the triethylene glycol regeneration burner 10 from flowing back and generating combustion. The triethylene glycol regeneration burner 10 is used to burn and reuse the recovered natural gas. The gas generated during combustion is discharged through the combustion vent 11 under the action of the unpowered wind cap 12;

[0034] On the drain pipeline 300, a separator drain control valve 110, a filter 8, a lift pump inlet control valve 109, a lift pump 7, a drain manual valve 108, and a drain interface 6 are sequentially arranged along the direction of liquid transportation. Among them, the gas-liquid separator 4 uses gravity to separate the mixed liquid of triethylene glycol and a small amount of water. The lift pump 7 is used to drive the mixed liquid to flow towards the drain interface 6.

[0035] In addition, a liquid level transmitter 9 for detecting the liquid level height in the tank of the gas-liquid separator 4 is further provided on the inner side wall of the gas-liquid separator 4. The liquid level transmitter 9 is electrically connected to the separator liquid discharge control valve 110, and controls 20-80% of the volume of the tank of the gas-liquid separator 4 through the separator liquid discharge control valve 110. The liquid level transmitter 9 is also electrically connected to the lift pump inlet control valve 109. Among them, the liquid level transmitter 9 is used to monitor the liquid level in the tank of the gas-liquid separator 4. When the liquid level in the tank is higher than a certain value, the lift pump 7 and the corresponding valves are automatically started to discharge the liquid, so as to always control the liquid level of the gas-liquid separator 4 at 20-80%, preventing the lift pump 7 from starting and stopping frequently.

[0036] In addition, at least one group of stop valves, at least one group of data acquisition mechanisms for detecting temperature, pressure or flow rate, and a controller are respectively connected to the triethylene glycol reboiler tail gas inlet pipeline 100, the vent pipeline 200, the drain pipeline 300, and the gas pipeline 400, wherein the controller is electrically connected to the data acquisition mechanism. A data acquisition mechanism for detecting temperature is provided on the heat exchanger 3. The controller controls the temperature of the gas-liquid mixture at the discharge port of the heat exchanger 3 at 45-60°C according to the temperature signal detected by the data acquisition mechanism, ensuring the cooling effect of the gas-liquid separator 4 on water vapor and at the same time avoiding the freezing of condensed water due to too low temperature.

[0037] The working principle of the present utility model:

[0038] During normal use, the vent pipeline 200 should be closed, that is, the reboiler vent control valve 104 and the separator vent control valve 105 should be closed.

[0039] First, the triethylene glycol tail gas discharged from the exhaust port of the triethylene glycol reboiler 1 flows into the gas-liquid separator 4 through the tail gas inlet pipeline 100. The tail gas inlet pipeline 100 is successively provided with a tail gas inlet control valve 101, a variable frequency fan 2, a heat exchanger inlet control valve 102, a heat exchanger 3 for cold treatment of the tail gas, and a gas-liquid separator inlet control valve 103. The variable frequency fan 2 is used to control the pressure and flow rate of the gas in the tail gas inlet pipeline 100. The gas flows through the heat exchanger 3 for cold treatment of the tail gas. The heat exchanger 3 condenses the water vapor, hydrocarbons, and triethylene glycol mixed in the tail gas, and then enters the gas-liquid separator 4 for gas-liquid separation.

[0040] Among them, the natural gas separated by the gas-liquid separator 4 enters the triethylene glycol regeneration burner 10 through the gas pipeline 400 and serves as the fuel for the triethylene glycol regeneration burner 10, realizing the recovery and reuse of the natural gas energy in the tail gas of the triethylene glycol reboiler 1. A burner intake control valve 106, a flame arrester 107, the triethylene glycol regeneration burner 10, a combustion vent 11, and a non-powered wind cap 12 are sequentially arranged on the gas pipeline 400. The flame arrester 107 is used to prevent the natural gas in the triethylene glycol regeneration burner 10 from flowing back and causing combustion. The gas generated by the triethylene glycol regeneration burner 10 is discharged through the combustion vent 11 under the action of the non-powered wind cap 12. The non-powered wind cap uses wind energy to play a negative pressure suction role, eliminating the use of an ejector and its supporting automatic control device, simplifying the device process, and reducing energy consumption at the same time.

[0041] Among them, the liquid separated by the gas-liquid separator 4 is discharged through the drain pipe 300 via the drain port below the gas-liquid separator. A separator drain control valve 110, a filter 8, a lift pump inlet control valve 109, a lift pump 7, a drain manual valve 108, and a drain interface 6 are sequentially arranged on the drain pipe 300. The gas-liquid separator 4 uses gravity to separate the mixed liquid of triethylene glycol and a small amount of water and discharges it through the drain port below the gas-liquid separator 4. The mixed liquid flows along the drain pipe under the action of the lift pump 7, passes through the filter 8 for filtration, and is discharged through the drain interface 6.

[0042] Embodiment 2

[0043] As Figure 2 shown, in case of emergencies such as equipment maintenance, valve maintenance, or pipeline pressure exceeding the normal range in the tail gas recovery and treatment device, the reboiler vent control valve 104 and the separator vent control valve 105 can be opened to vent the gas in the pipeline and equipment through the vent pipe 200.

[0044] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A tail gas recovery and treatment device for a triethylene glycol reboiler, the tail gas recovery and treatment device comprising a tail gas inlet pipeline (100), a drain pipeline (300) and a fuel gas pipeline (400), wherein the head and tail ends of the tail gas inlet pipeline (100) are respectively connected to the exhaust port of the triethylene glycol reboiler (1) and the air inlet of the side wall of a gas-liquid separator (4), the fuel gas pipeline (400) is connected to the exhaust port at the top of the gas-liquid separator (4), and the drain pipeline (300) is connected to the drain port at the bottom of the gas-liquid separator (4); Features: The exhaust gas inlet pipeline (100) is provided with an exhaust gas inlet control valve (101), a variable frequency fan (2), a heat exchanger inlet control valve (102), a heat exchanger (3) and a gas-liquid separator inlet control valve (103) in sequence along the exhaust gas conveying direction; The gas pipeline (400) is provided with a burner air intake control valve (106), a flame arrester (107), a triethylene glycol regeneration burner (10) and a combustion vent (11) in sequence along the direction of gas transportation, and a non-powered air hood (12) is rotatably connected to the top of the combustion vent (11) and is in communication with the combustion vent; The liquid discharge pipeline (300) is provided with a separator liquid discharge control valve (110), a filter (8), a lift pump liquid inlet control valve (109), a lift pump (7), a liquid discharge manual valve (108) and a liquid discharge interface (6) in sequence along the direction of liquid delivery.

2. The triethylene glycol reboiler tail gas recovery and treatment device according to claim 1, characterized in that: The tail gas recovery and treatment device further comprises a venting pipeline (200), wherein the venting pipeline (200) is in communication with the tail gas intake pipeline (100) and the fuel gas pipeline (400).

3. The triethylene glycol reboiler tail gas recovery and treatment device according to claim 2, characterized in that: The vent pipeline (200) comprises a vent pipeline A and a vent pipeline B, wherein the vent pipeline A is connected to the exhaust gas inlet pipeline (100) between the exhaust gas inlet control valve (101) and the variable frequency fan (2), and the vent pipeline B is connected to the fuel gas pipeline (400) between the burner intake control valve (106) and the gas-liquid separator (4).

4. The tail gas recovery and treatment device of triethylene glycol reboiler according to claim 3 is characterized in that: The vent line A is provided with a reboiler vent control valve (104), the vent line B is provided with a separator vent control valve (105), and the tail ends of the vent line A and the vent line B are jointly provided with a vent exhaust interface (5).

5. The tail gas recovery and treatment device of triethylene glycol reboiler according to claim 1, characterized in that: A liquid level transmitter (9) for detecting the liquid level height in the tank of the gas-liquid separator (4) is also provided on the inner wall of the gas-liquid separator (4); the liquid level transmitter (9) is electrically connected to the separator discharge control valve (110), and controls 20-80% of the volume of the tank of the gas-liquid separator (4) through the separator discharge control valve (110).

6. The tail gas recovery and treatment device of triethylene glycol reboiler according to claim 5, characterized in that: The liquid level transmitter (9) is also electrically connected to the lift pump liquid inlet control valve (109).

7. The tail gas recovery and treatment device of triethylene glycol reboiler according to claim 1, characterized in that: The heat exchanger (3) is provided with a data acquisition mechanism for detecting temperature, and the temperature of the gas-liquid mixture at the outlet of the heat exchanger (3) is controlled at 45-60°C according to the temperature signal detected by the data acquisition mechanism.

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