Triethylene glycol regenerative tail gas treatment device and method

Abstract

The application discloses a triethylene glycol regeneration pry tail gas treatment device and method, comprising a cooling system, a separation system, a pressurization system and a waste liquid discharge system. The application is equipped with a bypass through a tail gas air cooler, and the interlocking automatic start-stop of the air cooler is realized in a temperature control mode, so that the use of the application is not limited by regions, and the applicability of the application at different temperatures is enhanced. The application uses a tail gas pressurization ejector after a tail gas separator, and the separated gas phase is self-pressurized from normal pressure to 8-15 kPa through the injection of fuel gas in the tail gas pressurization ejector, and then is burned in a regeneration pry burner, so that the risk of equipment shutdown caused by unstable gas supply of the burner cavity is overcome. The application introduces fuel gas as the pressure supplement of the tail gas separator, so that the normal operation of the application in the fault maintenance state of the lifting pump is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to a tail gas treatment device and method, in particular to a triethylene glycol regeneration pry tail gas treatment device and method. BACKGROUND

[0002] In the process of natural gas exploitation, the natural gas flowing out of the wellhead is almost saturated with gas phase water, and even carries a certain amount of liquid water. The presence of water in natural gas often causes serious consequences: under certain conditions, natural gas hydrates are formed to block valves, pipelines and equipment, reduce pipeline transportation capacity, and cause unnecessary power consumption.

[0003] The triethylene glycol dehydration technology has been widely used in the natural gas industry due to its good dehydration effect, high heat exchange efficiency and other unique advantages. The main components of the tail gas generated are water vapor, a certain amount of natural gas, a small amount of triethylene glycol and by-products (formic acid, formaldehyde and aromatic hydrocarbons), and random discharge has great harm to the natural environment and the health of workers. The existing triethylene glycol regeneration pry tail gas treatment device mainly has the following problems:

[0004] ① The design of forced ventilation by using a blower cannot effectively ensure the continuity and stability of the gas combustion in the regeneration pry after passing through the tail gas separator, which easily causes unstable gas supply in the burner cavity, affects the air-fuel ratio, and often causes the regeneration pry furnace to extinguish, affecting the normal operation of the entire triethylene glycol dehydration device.

[0005] ② The air cooler used in the system cannot ensure the applicability after the environmental temperature is reduced, and liquid accumulation and freezing often occur during winter operation, causing equipment overpressure, shutdown and other situations.

[0006] ③ The liquid phase treated by the tail gas separator can only be transported to the closed discharge tank for discharge by using a waste water lifting pump, which cannot meet the production operation needs under all working conditions. Once the lifting pump fails or needs maintenance, the equipment must be stopped. SUMMARY

[0007] In view of the existing technical deficiencies, the present application provides a triethylene glycol regeneration pry tail gas treatment device and method.

[0008] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0009] A triethylene glycol regeneration pry tail gas treatment device, comprising a cooling system, a separation system, a pressurization system and a waste liquid discharge system, characterized in that the cooling system comprises a three-way air control valve, the first outlet and the second outlet of the three-way air control valve are connected with the main pipeline through the first branch line and the second branch line respectively,

[0010] Wherein, the first branch line is provided with a tail gas air cooler, the main pipeline is provided with a temperature transmitter, the tail gas air cooler, the temperature transmitter, the three-way air control valve and the temperature main control unit are connected, the pressure difference main control unit is connected with the first branch line, the second branch line, the three-way air control valve and the tail gas air cooler;

[0011] The separation system comprises a tail gas separator connected with the main pipeline, a liquid level transmitter is arranged on the tail gas separator, a top outlet of the tail gas separator is connected with the pressurization system through a third branch line, and a bottom outlet of the tail gas separator is connected with the waste liquid discharge system through a fourth branch line;

[0012] The pressurization system comprises a tail gas pressurization ejector, a top outlet of the tail gas pressurization ejector is connected with the combustor through a fifth branch line, a bottom inlet of the tail gas pressurization ejector is connected with the fuel gas buffer tank through a sixth branch line, and the fuel gas buffer tank is connected with the tail gas separator through a seventh branch line;

[0013] The waste liquid discharge system comprises a waste water lifting pump, an inlet of the waste water lifting pump is connected with the bottom outlet of the tail gas separator, an outlet of the waste water lifting pump is connected with a blowdown closed discharge tank, an eighth branch line is connected with the tail gas separator, and an outlet of the eighth branch line is connected with the blowdown closed discharge tank.

[0014] On the basis of the above scheme, as a preferred, the temperature main control unit comprises a temperature calculation unit and a temperature control unit, the temperature transmitter is connected with the temperature calculation unit through an electric signal line, the temperature calculation unit is connected with the temperature control unit through an electric signal line, the temperature control unit is connected with the motor of the tail gas air cooler through an electric signal line, and the temperature control unit is further connected with the three-way air control valve through a gas signal line.

[0015] On the basis of the above scheme, as a preferred, the pressure difference main control unit comprises a pressure difference display unit, a pressure difference calculation unit and a pressure difference control unit, the pressure difference display unit is connected with the first branch line and the second branch line respectively, the pressure difference display unit is connected with the pressure difference calculation unit through an electric signal line, the pressure difference calculation unit is connected with the pressure difference control unit through an electric signal line, and the pressure difference control unit is connected with the three-way air control valve and the motor of the tail gas air cooler through a gas signal line respectively.

[0016] On the basis of the above scheme, as a preferred, the tail gas enters the three-way air control valve through the pipeline.

[0017] A triethylene glycol regeneration pry tail gas treatment method, using the treatment device for treatment, comprising the following steps:

[0018] Step one: in the cooling system, the temperature is detected in real time through the temperature transmitter, and the temperature is compared with the set value, and the working state of the three-way air control valve and the tail gas air cooler is controlled according to the comparison result, at the same time, the pressure difference main control unit controls the working state of the three-way air control valve and the tail gas air cooler, and the priority of the pressure difference is higher than that of the temperature.

[0019] Step two: the tail gas enters the tail gas separator from the main pipeline, the tail gas separator divides the tail gas into gas phase and liquid phase, the gas phase is discharged through the top outlet of the tail gas separator and enters the booster system through the third branch line, the liquid phase is discharged through the bottom outlet of the tail gas separator and enters the waste liquid discharge system through the fourth branch line; the fuel gas comes from the fuel gas buffer tank and enters the tail gas separator through the seventh branch line to provide pressure compensation for the liquid phase discharged from the tail gas separator;

[0020] Step three: the gas phase enters the tail gas booster ejector through the third branch line, the fuel gas output from the fuel gas buffer tank enters the tail gas booster ejector through the sixth branch line, and in the tail gas booster ejector, the gas phase is self-boosted from normal pressure to 8-15 kPa through the injection of the fuel gas, and then the gas phase goes to the regenerative torch for combustion through the fifth branch line.

[0021] Step four: the liquid phase enters the waste water booster pump through the fourth branch line, and the liquid phase is transported into the blowdown closed drain tank by the waste water booster pump; the liquid phase can also be directly discharged into the blowdown closed drain tank through the eighth branch line.

[0022] On the basis of the above scheme, as a preferred, when the temperature transmitter detects the temperature, the temperature information is transmitted to the temperature calculation unit, and the temperature calculation unit judges, when the temperature is higher than the set temperature, the opening electric signal is transmitted to the temperature control unit, the temperature control unit transmits the opening electric signal to the motor, the motor starts to run, and the temperature control unit converts the opening electric signal into an opening gas signal and transmits it to the three-way air control valve, the three-way air control valve opens the first outlet, the tail gas can enter the tail gas air cooler through the first outlet from the first branch line, and the tail gas is cooled by the tail gas air cooler and then enters the main pipeline; when the temperature is lower than the set temperature, the temperature calculation unit transmits the closing electric signal to the temperature control unit, the temperature control unit transmits the closing electric signal to the motor, the motor stops running, and the temperature control unit converts the closing electric signal into a closing gas signal and transmits it to the three-way air control valve, the three-way air control valve opens the second outlet, and the tail gas can directly enter the main pipeline through the second outlet from the second branch line; the differential pressure display unit is connected with the first branch line and the second branch line respectively, which can detect the pressure difference of the two branch lines, and transmit the pressure difference information to the differential pressure calculation unit, and the differential pressure calculation unit judges, when the pressure difference is higher than the set value, the differential pressure calculation unit transmits the closing electric signal to the differential pressure control unit, the differential pressure control unit converts the closing electric signal into a closing gas signal, the differential pressure control unit transmits the closing gas signal to the motor, the motor stops running, and the closing gas signal is transmitted to the three-way air control valve, the three-way air control valve opens the second outlet, and the tail gas can directly enter the main pipeline through the second outlet from the second branch line.

[0023] The beneficial effects of the present application are as follows:

[0024] This invention overcomes the risk of equipment shutdown caused by unstable gas supply to the burner furnace by using an exhaust gas booster ejector after the exhaust gas separator. The separated gas phase is boosted from atmospheric pressure to 8-15 kPa by the fuel gas in the exhaust gas booster ejector before being burned in the regeneration skid burner.

[0025] This invention adds a bypass to the exhaust gas air cooler and uses temperature control to achieve interlocking automatic start and stop of the air cooler, making the use of this invention not limited by region and enhancing its applicability at different temperatures.

[0026] This invention ensures the normal operation of the invention under maintenance conditions by introducing fuel gas as a pressure supplement to the exhaust gas separator.

[0027] This invention employs dual control of differential pressure and temperature, with differential pressure having a higher priority than temperature to ensure stable system operation. When differential pressure becomes abnormal, adjustment is prioritized based on differential pressure, which can prevent equipment failures, pipeline blockages, and other problems caused by insufficient or excessive differential pressure. In particular, adjustment can be made in the early stages of complete ice blockage.

[0028] Improving energy efficiency: Temperature in this system is significantly affected by exhaust gas temperature and ambient temperature, and temperature rise and fall take time, making it less sensitive than differential pressure control. Prioritizing differential pressure allows for timely adjustments to system flow, preventing equipment from continuing to operate under unreasonable differential pressure conditions due to temperature control being prioritized, thus avoiding energy waste, equipment malfunctions, and safety hazards.

[0029] Extending equipment lifespan and improving control precision: This combination allows for more precise control based on a combination of pressure differential and temperature, meeting the needs of different operating conditions. In industrial production, it enables more stable production processes in areas with strict temperature and pressure requirements.

[0030] In summary, this invention reduces the risks of pipeline and equipment freezing, overpressure, equipment damage, and production stoppages, while also making reasonable and full recovery and utilization of exhaust gas, reducing exhaust gas emissions, and making it cleaner and more environmentally friendly. Attached Figure Description

[0031] Figure 1 This is a connection block diagram of the present invention. Detailed Implementation

[0032] like Figure 1As shown, this invention provides a triethylene glycol regeneration skid exhaust gas treatment device, including a cooling system 1, a separation system 2, a pressurization system 3, and a waste liquid discharge system 4. Exhaust gas enters the cooling system 1 through a pipeline. The cooling system 1 includes a three-way pneumatic control valve 101, an exhaust gas air cooler 102, a first branch line 103, a second branch line 104, a main line 105, a temperature transmitter 106, a temperature calculation unit 107, a temperature control unit 108, a motor 109, a differential pressure calculation unit 110, a differential pressure display unit 111, and a differential pressure control unit 112. Exhaust gas enters the three-way pneumatic control valve 101 through a pipeline. The first outlet of the three-way pneumatic control valve 101 is connected to the exhaust gas air cooler 102 through the first branch line 103, and the second outlet of the three-way pneumatic control valve 101 is connected to the main line 105 through the second branch line 104. The exhaust gas air cooler 102 is connected to the main line 105 through the first branch line 103. The exhaust gas air cooler 102 is equipped with a motor 109. The main pipeline 105 is equipped with a temperature transmitter 106. The temperature transmitter 106 is connected to a temperature calculation unit 107 via an electrical signal line. The temperature calculation unit 107 is connected to a temperature control unit 108 via an electrical signal line. The temperature control unit 108 is connected to the motor 109 via an electrical signal line. The temperature control unit 108 is also connected to a three-way pneumatic control valve 101 via a pneumatic signal line. The differential pressure display unit 111 is connected to the first branch line 103 and the second branch line 104 respectively. The differential pressure display unit 111 is connected to a differential pressure calculation unit 110 via an electrical signal line. The differential pressure calculation unit 110 is connected to a differential pressure control unit 112 via an electrical signal line. The differential pressure control unit 112 is connected to the three-way pneumatic control valve 101 and the motor 109 respectively via pneumatic signal lines. The main pipeline 105 is connected to the separation system 2.

[0033] The separation system 2 includes an exhaust gas separator 201, a level transmitter 202, a third branch line 203, and a fourth branch line 204. The exhaust gas separator 201 is equipped with a level transmitter 202. The top outlet of the exhaust gas separator 201 is connected to the pressurization system 3 through the third branch line 203, and the bottom outlet of the exhaust gas separator 201 is connected to the waste liquid discharge system 4 through the fourth branch line 204.

[0034] The booster system 3 includes an exhaust gas booster ejector 301, a fifth branch line 302, a sixth branch line 303, and a seventh branch line 304. The top outlet of the exhaust gas booster ejector 301 is connected to the burner 5 through the fifth branch line 302, and the bottom inlet of the exhaust gas booster ejector 301 is connected to the fuel gas buffer tank 6 through the sixth branch line 303. The fuel gas buffer tank 6 is connected to the exhaust gas separator 201 through the seventh branch line 304.

[0035] The waste liquid discharge system 4 includes a wastewater lift pump 401 and an eighth branch line 402. The inlet of the wastewater lift pump 401 is connected to the bottom outlet of the tail gas separator 201, and the outlet of the wastewater lift pump 401 is connected to a closed discharge tank 7. The inlet of the eighth branch line 402 is connected to the tail gas separator 201, and the outlet of the eighth branch line 402 is connected to the closed discharge tank 7.

[0036] A method for treating the exhaust gas from a triethylene glycol regeneration skid includes the following steps:

[0037] Step 1: Exhaust gas enters cooling system 1; the exhaust gas reaches the three-way pneumatic control valve 101, which has a first outlet and a second outlet. When the temperature transmitter 106 detects the temperature, it transmits the temperature information to the temperature calculation unit 107. The temperature calculation unit 107 makes a judgment. When the temperature is higher than the set temperature, it transmits an opening electrical signal to the temperature control unit 108. The temperature control unit 108 transmits the opening electrical signal to the motor 109, which starts running. The temperature control unit 108 converts the opening electrical signal into an opening pneumatic signal and transmits it to the three-way pneumatic control valve 101. The three-way pneumatic control valve 101 opens the first outlet, and the exhaust gas can enter the exhaust gas air cooler 102 through the first branch line 103 via the first outlet. The exhaust gas air cooler 102 cools the exhaust gas before it enters the main line 105. When the temperature is lower than the set temperature, the temperature calculation unit 107 transmits a closing electrical signal to the temperature control unit 108, which transmits the closing electrical signal to the motor 109. The motor 109 stops running, and the temperature control unit 108 converts the shut-off electrical signal into a shut-off pneumatic signal and transmits it to the three-way pneumatic control valve 101. The three-way pneumatic control valve 101 opens the second outlet, and the exhaust gas can directly enter the main line 105 through the second branch line 104 via the second outlet. The differential pressure display unit 111 is connected to the first branch line 103 and the second branch line 104 respectively and can detect the differential pressure between the two branches. It transmits the differential pressure information to the differential pressure calculation unit 110, which makes a judgment. When the differential pressure is higher than the set value, the differential pressure calculation unit 110 transmits a shut-off electrical signal to the differential pressure control unit 112. The differential pressure control unit 112 converts the shut-off electrical signal into a shut-off pneumatic signal and transmits the shut-off pneumatic signal to the motor 109. The motor 109 stops running and transmits the shut-off pneumatic signal to the three-way pneumatic control valve 101. The three-way pneumatic control valve 101 opens the second outlet, and the exhaust gas can directly enter the main line 105 through the second branch line 104 via the second outlet.

[0038] Step 2: Exhaust gas enters separation system 2; exhaust gas enters exhaust gas separator 201 from main line 105. Exhaust gas separator 201 separates exhaust gas into gas phase and liquid phase. Gas phase is discharged through top outlet of exhaust gas separator 201 and enters pressurization system 3 through third branch line 203. Liquid phase is discharged through bottom outlet of exhaust gas separator 201 and enters waste liquid discharge system 4 through fourth branch line 204; fuel gas comes from fuel gas buffer tank 6 and enters exhaust gas separator 201 through seventh branch line 304 to provide pressure supplement for liquid phase discharged from exhaust gas separator 201.

[0039] Step 3: The gas phase enters the pressurization system 3; the gas phase enters the exhaust gas pressurization ejector 301 via the third branch line 203. The fuel gas output from the fuel gas buffer tank 6 enters the exhaust gas pressurization ejector 301 via the sixth branch line 303. In the exhaust gas pressurization ejector 301, the fuel gas is pressurized from atmospheric pressure to 8-15 kPa through the ejection of the fuel gas. Then the gas phase goes to the regeneration skid burner 5 for combustion via the fifth branch line 302.

[0040] Step 4: The liquid phase enters the waste liquid discharge system 4; the liquid phase enters the wastewater lift pump 401 via the fourth branch line 204, and the wastewater lift pump 401 transports the liquid phase into the closed discharge tank 7. The liquid phase can also be directly discharged into the closed discharge tank 7 via the eighth branch line 402.

[0041] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Simple modifications and substitutions made by those skilled in the art without departing from the spirit and scope of the invention are within the protection scope of the present invention.

Claims

1. A triethylene glycol regeneration skid tail gas treatment device, comprising a cooling system, a separation system, a pressurization system, and a waste liquid discharge system, characterized in that, The cooling system includes a three-way pneumatic control valve. The first and second outlets of the three-way pneumatic control valve are connected to the main pipeline via the first and second branch lines, respectively. The first branch line is equipped with an exhaust gas air cooler, the main line is equipped with a temperature transmitter, the exhaust gas air cooler, the temperature transmitter, the three-way pneumatic control valve are connected to the temperature main control unit, and the differential pressure main control unit is connected to the first branch line, the second branch line, the three-way pneumatic control valve, and the exhaust gas air cooler. The separation system includes a tail gas separator connected to the main pipeline, a liquid level transmitter on the tail gas separator, a top outlet of the tail gas separator connected to a pressurization system via a third branch line, and a bottom outlet of the tail gas separator connected to a waste liquid discharge system via a fourth branch line. The supercharging system includes an exhaust gas supercharger ejector. The top outlet of the exhaust gas supercharger ejector is connected to the burner via the fifth branch line, and the bottom inlet of the exhaust gas supercharger ejector is connected to the fuel gas buffer tank via the sixth branch line. The fuel gas buffer tank is connected to the exhaust gas separator via the seventh branch line. The waste liquid discharge system includes a wastewater lift pump, the inlet of which is connected to the bottom outlet of the exhaust gas separator, the outlet of which is connected to a closed-loop discharge tank, the inlet of the eighth branch line is connected to the exhaust gas separator, and the outlet of the eighth branch line is connected to the closed-loop discharge tank.

2. The triethylene glycol regeneration skid tail gas treatment device as described in claim 1, characterized in that, The temperature control unit includes a temperature calculation unit and a temperature control unit. The temperature transmitter is connected to the temperature calculation unit via an electrical signal line. The temperature calculation unit is connected to the temperature control unit via an electrical signal line. The temperature control unit is connected to the motor of the exhaust gas air cooler via an electrical signal line. The temperature control unit is also connected to the three-way pneumatic control valve via a pneumatic signal line.

3. The triethylene glycol regeneration skid tail gas treatment device as described in claim 1, characterized in that, The differential pressure control unit includes a differential pressure display unit, a differential pressure calculation unit, and a differential pressure control unit. The differential pressure display unit is connected to the first branch line and the second branch line respectively. The differential pressure display unit is connected to the differential pressure calculation unit through an electrical signal line. The differential pressure calculation unit is connected to the differential pressure control unit through an electrical signal line. The differential pressure control unit is connected to the motor of the three-way pneumatic control valve and the exhaust gas air cooler respectively through a pneumatic signal line.

4. The triethylene glycol regeneration skid tail gas treatment device as described in claim 1, characterized in that, Exhaust gas enters the three-way pneumatic control valve through the pipeline.

5. A method for treating the exhaust gas from a triethylene glycol regeneration skid, comprising treating the gas using the treatment apparatus as described in any one of claims 1-4, characterized in that, Includes the following steps: Step 1: In the cooling system, the temperature is detected in real time by the temperature transmitter and compared with the set value. Based on the comparison result, the working status of the three-way pneumatic control valve and the exhaust air cooler is controlled. At the same time, the differential pressure control unit controls the working status of the three-way pneumatic control valve and the exhaust air cooler based on the differential pressure. The priority of differential pressure is higher than that of temperature. Step 2: The exhaust gas enters the exhaust gas separator from the main pipeline. The exhaust gas separator separates the exhaust gas into a gas phase and a liquid phase. The gas phase is discharged through the top outlet of the exhaust gas separator and enters the pressurization system through the third branch line. The liquid phase enters the waste liquid discharge system through the bottom outlet of the exhaust gas separator and enters the waste liquid discharge system through the fourth branch line. Fuel gas comes from the fuel gas buffer tank, passes through the seventh branch line and enters the tail gas separator, providing pressure replenishment for the liquid phase discharged from the tail gas separator. Step 3: The gas phase enters the exhaust gas booster ejector via the third branch line. The fuel gas output from the fuel gas buffer tank enters the exhaust gas booster ejector via the sixth branch line. In the exhaust gas booster ejector, the fuel gas is boosted from atmospheric pressure to 8-15 kPa through the ejection of the fuel gas. Then the gas phase goes to the regeneration skid burner for combustion via the fifth branch line. Step 4: The liquid phase enters the wastewater lift pump via the fourth branch line, and the wastewater lift pump transports the liquid phase into the closed discharge tank. The liquid phase can also be directly discharged into the closed discharge tank via the eighth branch line.

6. The method for treating the exhaust gas from a triethylene glycol regeneration skid as described in claim 5, characterized in that, In step 1, after the temperature transmitter detects the temperature, it transmits the temperature information to the temperature calculation unit. The temperature calculation unit then determines whether the temperature is higher than the set temperature. If the temperature is higher than the set temperature, it sends an opening electrical signal to the temperature control unit. The temperature control unit then transmits the opening electrical signal to the motor, which starts the motor. The temperature control unit also converts the opening electrical signal into an opening pneumatic signal and transmits it to the three-way pneumatic control valve. The three-way pneumatic control valve opens the first outlet, allowing the exhaust gas to enter the exhaust gas air cooler through the first outlet and the first branch line. The exhaust gas air cooler cools the exhaust gas before it enters the main pipeline. If the temperature is lower than the set temperature, the temperature calculation unit sends a closing electrical signal to the temperature control unit. The temperature control unit then transmits the closing electrical signal to the motor, which stops the motor. The temperature control unit then closes the outlet. The electrical signal is converted into a shut-off air signal and transmitted to the three-way pneumatic control valve. The three-way pneumatic control valve opens the second outlet, allowing exhaust gas to directly enter the main pipeline via the second branch line. The differential pressure display unit is connected to the first and second branches respectively and can detect the pressure difference between the two branches. It transmits the pressure difference information to the differential pressure calculation unit, which makes a judgment. When the pressure difference is higher than the set value, the differential pressure calculation unit transmits a shut-off electrical signal to the differential pressure control unit. The differential pressure control unit converts the shut-off electrical signal into a shut-off air signal and transmits the shut-off air signal to the motor. The motor stops running and transmits the shut-off air signal to the three-way pneumatic control valve, which opens the second outlet, allowing exhaust gas to directly enter the main pipeline via the second branch line.

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