A stripping system for CO2 removal from MDEA decarbonization wastewater

Abstract

The utility model discloses a kind of MDEA decarburization wastewater CO2 removal with stripping system, including flash tank, first liquid guide pipe and gas guide pipe, the flash tank top is provided with exhaust pipe;The first liquid guide pipe is connected with the feed inlet of flash tank and is used for introducing MDEA decarburization wastewater;The gas guide pipe is connected with first liquid guide pipe and is used for introducing compressed gas with certain pressure;Compared with prior art, gas guide pipe enters compressed gas with certain pressure into first liquid guide pipe to mix with MDEA decarburization wastewater introduced in first liquid guide pipe, and MDEA decarburization wastewater and compressed gas after mixing enter into flash tank, pressure drops suddenly, so that compressed gas takes out CO2 in MDEA decarburization wastewater in the form of bubble, is discharged through exhaust pipe, so as to adjust the pH value of MDEA decarburization wastewater to meet the receiving standard of sewage treatment plant, and its system structure is simple.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, specifically to a stripping system for CO2 removal from MDEA decarbonization wastewater. Background Technology

[0002] In the MDEA (methyldiethanolamine) heating and regeneration cycle process, process wastewater is continuously generated. This wastewater is transported to the park's wastewater treatment plant through a closed pipeline for treatment, and its pH value is controlled within the range of 6 to 9 to meet the wastewater treatment plant's acceptance standards.

[0003] However, in the actual production process, CO2 gas remains in the MDEA decarbonation wastewater. This CO2 dissolves in the wastewater to form a carbonic acid system (mainly CO2·H2O, with trace amounts of H2CO3). At room temperature and pressure, the saturated concentration of this carbonic acid system is approximately 0.033 mol / L. Due to partial dissociation to generate H+, the MDEA decarbonation wastewater is weakly acidic. Actual testing showed that the pH value of the MDEA decarbonation wastewater was 5.6, lower than the acceptance standard of the wastewater treatment plant. Therefore, a treatment system is needed to remove the CO2 from the MDEA decarbonation wastewater to bring its pH value up to the acceptance standard of the wastewater treatment plant. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a stripping system for CO2 removal from MDEA decarbonization wastewater, so as to solve the problem that there is no equipment in the existing technology to remove CO2 from MDEA decarbonization wastewater so that the pH value of MDEA decarbonization wastewater meets the receiving standards of sewage treatment plants.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a stripping system for CO2 removal from MDEA decarbonization wastewater, comprising:

[0006] A flash evaporator, wherein an exhaust pipe is provided on the top of the flash evaporator;

[0007] The first liquid guide pipe is connected to the feed inlet of the flash tank and is used to introduce MDEA decarbonization wastewater.

[0008] A gas guide tube, which is connected to a first liquid guide tube and is used to introduce compressed gas with a certain pressure.

[0009] Compared with the prior art, the present invention has the following beneficial effects:

[0010] This CO2 stripping system for MDEA decarbonization wastewater mainly includes a flash tank. A gas inlet pipe introduces compressed gas at a certain pressure into the first liquid inlet pipe to mix with the MDEA decarbonization wastewater introduced in the first liquid inlet pipe. The mixed MDEA decarbonization wastewater and compressed gas then enter the flash tank, where a sudden pressure drop causes the compressed gas to carry away the CO2 from the MDEA decarbonization wastewater in the form of bubbles. The CO2 is then discharged through the exhaust pipe, thereby adjusting the pH value of the MDEA decarbonization wastewater to meet the acceptance standards of the wastewater treatment plant. The system has a simple structure. Attached Figure Description

[0011] Figure 1 This is a process flow diagram of one embodiment of the present invention.

[0012] The reference numerals in the accompanying drawings include: wastewater storage tank 1, flash tank 2, sewage tank 3, sewage pump 4, inlet pipe 5, first liquid guide pipe 6, gas guide pipe 7, exhaust pipe 8, second liquid guide pipe 9, external delivery pipe 10, return pipe 11, flow control valve 12, first regulating valve 13, second regulating valve 14, third regulating valve 15, pressure gauge 16, and fourth regulating valve 17. Detailed Implementation

[0013] The present invention will be further described in detail below through specific embodiments:

[0014] like Figure 1 As shown in the figure, this utility model embodiment proposes a stripping system for CO2 removal from MDEA decarbonization wastewater, including a flash tank 2, a first liquid guide pipe 6, and a gas guide pipe 7. The flash tank 2 is provided with an exhaust pipe 8 at the top. The first liquid guide pipe 6 is connected to the feed inlet of the flash tank 2 and is used to introduce MDEA decarbonization wastewater. The gas guide pipe 7 is connected to the first liquid guide pipe 6 and is used to introduce compressed gas with a certain pressure.

[0015] This CO2 stripping system for MDEA decarbonization wastewater mainly includes a flash tank 2 and a gas inlet pipe 7. Compressed gas with a certain pressure is introduced into the first liquid inlet pipe 6 to mix with the MDEA decarbonization wastewater introduced into the first liquid inlet pipe 6. The mixed MDEA decarbonization wastewater and compressed gas then enter the flash tank 2, where the pressure drops sharply. This causes the compressed gas to carry away the CO2 in the MDEA decarbonization wastewater in the form of bubbles, which is then discharged through the exhaust pipe 8. This adjusts the pH value of the MDEA decarbonization wastewater to meet the acceptance standards of the wastewater treatment plant. The system has a simple structure.

[0016] In this embodiment, the compressed gas is compressed air, which carries away the CO2 from the MDEA decarbonization wastewater and can be directly discharged into the atmosphere through exhaust pipe 8. The pressure of the compressed air is 7 kgf / cm². 2 .

[0017] In this utility model, the CO2 removal stripping system for MDEA decarbonization wastewater also includes a wastewater storage tank 1. The outlet of the wastewater storage tank 1 is connected to the first liquid guide pipe 6, and the inlet of the wastewater storage tank 1 is connected to an inlet pipe 5 for introducing MDEA decarbonization wastewater.

[0018] In the actual production process, the MDEA decarbonization wastewater generated during production is introduced into the wastewater storage tank 1 through the liquid inlet pipe 5 for storage. Then, the MDEA decarbonization wastewater stored in the wastewater storage tank 1 is exported through the first liquid guide pipe 6. It is mixed with the compressed air introduced by the air guide pipe 7 in the first liquid guide pipe 6 and then enters the flash tank 2. This ensures that the amount of MDEA decarbonization wastewater entering the flash tank 2 is relatively more stable.

[0019] In order to collect the CO2-removed MDEA decarbonization wastewater, the MDEA decarbonization wastewater CO2 removal stripping system also includes a wastewater tank 3, the inlet of which is connected to the outlet of the flash tank 2 through a second liquid guide pipe 9.

[0020] The MDEA decarbonization wastewater is discharged into the sewage tank 3 for collection after CO2 is removed in the flash tank 2 and then discharged through the second liquid guide pipe 9.

[0021] Furthermore, the CO2 removal stripping system for MDEA decarbonization wastewater also includes a wastewater pump 4, which is installed on the bottom side of the wastewater tank 3 and has an external delivery pipe 10 connected to its outlet.

[0022] Once a certain amount of MDEA decarbonization wastewater is collected in the wastewater tank 3, the wastewater pump 4 is started to transport the qualified MDEA decarbonization wastewater to the wastewater treatment plant for treatment through the external pipeline 10.

[0023] To maintain a certain liquid level in the wastewater tank 3 and prevent cavitation of the wastewater pump 4 from causing it to malfunction, a return pipe 11 extending to the bottom of the wastewater tank 3 is connected to the middle of the external delivery pipe 10. By guiding a portion of the MDEA decarbonization wastewater introduced into the external delivery pipe 10 back into the wastewater tank 3 through the return pipe 11, a certain liquid level can be maintained in the wastewater tank 3, ensuring that the wastewater pump 4 can continue to operate normally.

[0024] The CO2 removal stripping system for MDEA decarbonization wastewater described herein also includes a control unit. A flow control valve 12 connected to the control unit is installed on the first liquid guide pipe 6. A first regulating valve 13 connected to the control unit is installed on the gas guide pipe 7. A second regulating valve 14 connected to the control unit is installed on the second liquid guide pipe 9. A level controller connected to the control unit is installed on the flash tank 2. The driver of the sewage pump 4 is connected to the control unit. A check valve, a third regulating valve 15, and a pressure gauge 16 connected to the control unit are installed on the external delivery pipe 10. A fourth regulating valve 17 connected to the control unit is installed on the return pipe 11.

[0025] In this embodiment, the control unit is an existing controller, and the driver of the sewage pump 4 is a motor. The controller automatically controls the opening of the flow control valve 12, the first regulating valve 13, the second regulating valve 14, the check valve, the third regulating valve 15, and the fourth regulating valve 17, as well as the start and stop of the driver of the sewage pump 4, by using the liquid level feedback in the flash tank 2 from the liquid level controller and the pressure feedback on the external delivery pipe 10 from the pressure gauge 16, so as to regulate the flow of the first liquid guide pipe 6, the second liquid guide pipe 9, the external delivery pipe 10, and the return pipe 11, so that the CO2 removal stripping system for MDEA decarbonization wastewater can operate normally during operation.

[0026] The procedure for this control process is existing technology and will not be explained in detail here.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A stripping system for CO2 removal from MDEA decarbonization wastewater, characterized in that, include: A flash evaporator, wherein an exhaust pipe is provided on the top of the flash evaporator; The first liquid guide pipe is connected to the feed inlet of the flash tank and is used to introduce MDEA decarbonization wastewater. A gas guide tube, which is connected to a first liquid guide tube and is used to introduce compressed gas with a certain pressure; It also includes a wastewater storage tank, the drain of which is connected to the first liquid guide pipe, and the inlet of which is connected to an inlet pipe for introducing MDEA decarbonization wastewater. It also includes a wastewater tank, the inlet of which is connected to the outlet of the flash tank via a second liquid guide pipe; It also includes a sewage pump, which is installed on the bottom side of the sewage tank and has an external delivery pipe connected to its outlet. The middle part of the external delivery pipe is connected to a return pipe that extends to the bottom of the sewage tank. It also includes a control unit, a flow control valve connected to the control unit is installed on the first liquid guide pipe, a first regulating valve connected to the control unit is installed on the gas guide pipe, a second regulating valve connected to the control unit is installed on the second liquid guide pipe, a liquid level controller connected to the control unit is installed on the flash tank, a driver of the sewage pump is connected to the control unit, a check valve, a third regulating valve and a pressure gauge connected to the control unit are installed on the external delivery pipe, and a fourth regulating valve connected to the control unit is installed on the return pipe.

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