Continuous operation amine liquid circulation system and method

Abstract

The invention belongs to the technical field of amine desulfurization and decarburization, and particularly relates to a continuously operated amine liquid circulating system and method. The invention develops an amine liquid circulating system with high safety, high reliability and continuous operation for an amine process desulfurization and decarburization device. According to the system, a solution circulation system is analyzed and designed from multiple aspects of equipment type selection optimization, an automatic switching technology, pipeline arrangement, multiple safety protection and the like, and the safety and the reliability of uninterrupted operation of the system are effectively improved. According to the invention, the uninterrupted operation reliability of the device can be effectively improved, the production halt risk of the whole device is reduced, the production efficiency of a treatment plant is improved, the yield is further improved, and particularly in a high-sulfur natural gas treatment plant, the production safety is improved by reducing the field operation of operators.

Description

Technical Field

[0001] This invention belongs to the field of amine-based desulfurization and decarbonization technology, and specifically relates to a continuously operating amine liquid circulation system and method. Background Technology

[0002] Desulfurization and decarbonization equipment is an indispensable and important part of natural gas processing. According to the requirements of GB17820-2018, the instantaneous values ​​of total sulfur content and hydrogen sulfide content of Class I natural gas, as well as the average values ​​measured over any continuous 24 hours, are more stringent. Therefore, higher requirements are placed on the continuity and stability of the desulfurization system operation.

[0003] For natural gas desulfurization and decarbonization purification technologies, the "amine method" is currently widely used both domestically and internationally. The main solvent is methyl diethanolamine (MDEA) or a formulation based on it. The key to the amine method desulfurization and decarbonization process is the absorption and regeneration efficiency of the solution. After absorbing acidic gases, the amine-rich solution enters the amine regeneration system for regeneration and then returns to the absorption system, forming a circulating system. Therefore, ensuring the continuous and stable operation of the solution circulation system is crucial for the stable operation of this unit.

[0004] To ensure effective solution absorption, the solution circulation system is equipped with heat exchangers, pumps, filters, and other facilities. Failure of any equipment in the circulation system can lead to shutdowns of the desulfurization and decarbonization unit and even the natural gas processing plant. To avoid shutdowns due to equipment failure, a backup pump is typically installed, which is manually switched on-site by operators in case of failure. During pump switching, the amine solution circulation system is interrupted, thus affecting the operation of the amine solution desulfurization and decarbonization unit. The unit is equipped with a filtration system, which requires manual switching to ensure continuous operation. However, this manual switching poses a safety risk of delayed operation and H2S poisoning.

[0005] Especially in high-sulfur natural gas purification plants, where the equipment operates under corrosive media for extended periods, there is a higher risk of leakage at connections such as equipment, valves, and flanges. Therefore, on-site personnel operations should be minimized to prevent safety accidents. Summary of the Invention

[0006] In order to solve the above-mentioned problems in the prior art, the purpose of this invention is to provide a continuously operating amine liquid circulation system and method.

[0007] The technical solution adopted in this invention is as follows:

[0008] A continuously operating amine liquid circulation system includes a lean-rich liquid heat exchanger, a low-pressure lean liquid pump unit, a lean liquid cooler, an amine liquid pre-filter unit, an activated carbon filter, an amine liquid post-filter, and an amine liquid circulation pump unit connected in sequence via pipelines. The low-pressure lean liquid pump unit and the amine liquid circulation pump unit have the same pump switching system, which includes a first pump switching pipeline and a second pump switching pipeline connected in parallel. The amine liquid pre-filter unit includes a first filter switching pipeline and a second filter switching pipeline connected in parallel.

[0009] As a preferred embodiment of the present invention, along the medium flow direction, the first pump switching pipeline is sequentially connected to a first automatic control valve, a first first remote pressure gauge, a first pump, a second automatic control valve, a second first remote pressure gauge, and a third automatic control valve; the second pump switching pipeline is sequentially connected to a fourth automatic control valve, a first second remote pressure gauge, a second pump, a fifth automatic control valve, a second second remote pressure gauge, and a sixth automatic control valve; the first pump switching pipeline is connected to a first pump return line, which is connected to the outlet pipeline of the first pump, and a seventh automatic control valve is connected to the first pump return line; the second pump switching pipeline is connected to a second pump return line, which is connected to the outlet pipeline of the second pump, and an eighth automatic control valve is connected to the second pump return line; a ninth automatic control valve is connected to the outlet manifold of the first pump switching pipeline and the second pump switching pipeline.

[0010] As a preferred embodiment of the present invention, the first filter switching pipeline is sequentially connected to a tenth automatic control valve, a first pre-filter, and an eleventh automatic control valve, and a first differential pressure gauge is connected to the first pre-filter. The second filter switching pipeline is sequentially connected to a twelfth automatic control valve, a second pre-filter, and a thirteenth automatic control valve, and a second differential pressure gauge is connected to the second pre-filter.

[0011] As a preferred embodiment of the present invention, a filter bypass is further included, one end of which is connected to the pipeline between the amine pre-filter and the activated carbon filter, and the other end of which is connected between the amine post-filter and the amine circulation pump.

[0012] As a preferred embodiment of the present invention, a fourteenth automatic control valve is connected to the bypass of the filter, a fifteenth automatic control valve is connected to the inlet pipe of the activated carbon filter, a third differential pressure gauge is connected to the activated carbon filter, a sixteenth automatic control valve is connected to the outlet pipe of the amine liquid post-filter, and a fourth differential pressure gauge is connected to the amine liquid post-filter.

[0013] As a preferred embodiment of the present invention, the tube bundle inlet and outlet of the lean liquid cooler are provided with shut-off valves.

[0014] As a preferred embodiment of the present invention, it also includes a closed-circuit television monitoring system for monitoring the remote start-up, shutdown, and fault conditions of the lean liquid cooler.

[0015] As a preferred embodiment of the present invention, the lean and rich liquid heat exchanger is a shell-and-tube heat exchanger or a plate heat exchanger; the lean liquid cooler is replaced by an air cooler shell-and-tube heat exchanger or a plate heat exchanger.

[0016] A continuously operating amine solution recycling method includes the following steps:

[0017] Driving conditions:

[0018] Control of the amine liquid booster pump: First, open the second automatic control valve, then open the first automatic control valve; after the automatic tank pump is completed, remotely start the amine liquid booster pump. The seventh automatic control valve on the return line of the amine liquid booster pump automatically controls the return flow. After the amine liquid booster pump is fully started, remotely open the third automatic control valve.

[0019] Once the amine liquid booster pump is running stably, the control of the amine liquid circulation pump is as follows: first, open the second automatic control valve, then open the first automatic control valve; after the automatic tank pump is completed, remotely start the amine liquid circulation pump. The seventh automatic control valve on the return line of the amine liquid circulation pump automatically controls the return flow. After the amine liquid circulation pump is fully started, remotely open the third automatic control valve at the outlet of the amine liquid circulation pump.

[0020] Automatic restart switching under fault conditions:

[0021] When the first pump experiences abnormal signals, including vibration, temperature, pressure, outlet flow, and operating status, the first pump will shut down immediately, and the second pump will start automatically according to the control logic. The eighth automatic control valve on the return line of the second pump will automatically control the return flow. When the second pump is fully started, the sixth automatic control valve at the outlet of the second pump will open automatically.

[0022] The sixth automatic control valve at the outlet of the second pump is automatically started by presetting the valve to fully open, partially open, and fully closed states according to the pump motor selection; the eighth automatic control valve on the return line of the second pump matches the valve status on the outlet pipeline of the second pump and automatically presets the valve to the corresponding opening degree; the fifth automatic control valve is used to control the automatic venting of the second pump, or a high-point venting valve is set separately according to the outlet pipeline layout of the second pump for venting.

[0023] When the outlet pipeline shut-off valve of the amine circulating pump is a fully open manual valve, but the motor selection does not match the pump flow rate, the valve position opening of the ninth automatic control valve on the outlet manifold of the amine circulating pump needs to be preset to control the flow rate to meet the current when the motor starts. After a delay, the ninth automatic control valve is switched to automatic control.

[0024] The outlet pipelines of the first and second pumps are equipped with a single check valve or two check valves of different types; the stop signal of the first and second pumps simultaneously triggers the shut-off of the automatic control valve on the outlet pipeline.

[0025] Manual remote switching:

[0026] When the low-pressure lean solution pump or amine circulation pump needs to be periodically inspected, a remote switching command is given to switch the low-pressure lean solution pump or amine circulation pump. The second pump, according to the preset logic, first opens the fifth automatic shut-off valve at the high point of the second pump outlet to vent. The sixth automatic control valve at the outlet of the second pump and the eighth automatic control valve on the return line of the second pump are preset according to the motor selection of the second pump. Then the second pump starts. The first pump, according to the preset logic, stops when the second pump starts and runs normally, and then automatically closes the third automatic control valve on the outlet pipeline of the first pump.

[0027] Exhaust air using the second and fifth automatic control valves, or by using a high-point exhaust valve separately installed according to the outlet pipeline layout of the first and second pumps;

[0028] When the filter element of the first pre-filter causes the first differential pressure alarm due to blockage, and then causes overpressure due to blockage, it automatically switches to the second pre-filter.

[0029] For activated carbon filters and amine liquid post-filters, when the filter element is clogged and causes an alarm on the third or fourth differential pressure gauge, resulting in overpressure, the system will automatically switch to filter bypass.

[0030] As a preferred embodiment of the present invention, when controlling the amine liquid booster pump during the start-up process, the second automatic control valve is used to automatically vent the amine liquid booster pump, or a high-point venting valve is separately installed according to the outlet pipeline arrangement of the amine liquid booster pump for venting.

[0031] When controlling the amine circulation pump during operation, the third automatic control valve at the outlet of the amine circulation pump is automatically started by presetting the valve to fully open, partially open, and fully closed states according to the motor selection of the amine circulation pump; the seventh automatic control valve on the return line of the amine circulation pump matches the valve status on the outlet pipeline of the amine circulation pump and automatically presets the valve to the corresponding opening degree; the second automatic control valve is used to automatically vent the amine circulation pump, or a high-point vent valve is separately installed according to the outlet pipeline layout of the amine circulation pump for venting.

[0032] When the amine circulation pump is started with the valve fully open, but the motor selection does not match the pump flow rate, the valve position of the ninth automatic control valve is preset to control the flow rate to meet the current when the motor starts. After a delay, the ninth automatic control valve is switched to automatic control.

[0033] The beneficial effects of this invention are as follows:

[0034] 1. This invention develops an amine liquid circulation system for amine-based desulfurization and decarbonization equipment, which features high safety, high reliability, and continuous operation. This system can effectively improve the reliability of uninterrupted operation of the equipment, reduce the risk of shutdown of the entire equipment, and improve the production efficiency of the processing plant, thereby increasing output. Especially in high-sulfur natural gas processing plants, it improves production safety by reducing on-site operations by operators.

[0035] 2. This invention analyzes and designs the solution circulation system from multiple perspectives, including equipment selection optimization, automatic switching technology, pipeline layout, and multiple safety protections, effectively improving the safety and reliability of its uninterrupted operation. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall process flow of the present invention;

[0037] Figure 2 This is a schematic diagram of the pump process flow;

[0038] Figure 3 This is a schematic diagram of the filter process.

[0039] In the diagram: 1-Lean / Rich Solution Heat Exchanger; 2-Lean Solution Cooler; 3-Low-Pressure Lean Solution Pump; 4-Amine Solution Circulation Pump; 5-Amine Solution Pre-Filter; 6-Activated Carbon Filter; 7-Amine Solution Post-Filter; 8-Third Automatic Control Valve; 9-Seventh Automatic Control Valve; 10-First Remote Pressure Gauge; 11-Second Automatic Control Valve; 12-First Automatic Control Valve; 13-Sixth Automatic Control Valve; 14-Eighth Automatic Control Valve; 15-Fifth Automatic Control Valve; 16-Second Remote Pressure Gauge; 17-Fourth Automatic Control Valve; 18-Ninth Automatic Control Valve; 19-Tenth Automatic Control Valve; 20-First Differential Pressure Gauge; 21-Eleventh Automatic Control Valve; 22-Twelfth Automatic Control Valve; 23-Second Differential Pressure Gauge; 24-Thirteenth Automatic Control Valve; 25-Fourteenth Automatic Control Valve; 26-Fifteenth Automatic Control Valve; 27-Fourth Differential Pressure Gauge; 28-Sixteenth Automatic Control Valve; 29-Third Differential Pressure Gauge. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0042] like Figures 1-3 As shown, the continuously operating amine liquid circulation system of this embodiment includes a lean-rich liquid heat exchanger 1, a low-pressure lean liquid pump unit, a lean liquid cooler 2, an amine liquid pre-filter unit, an activated carbon filter 6, an amine liquid post-filter 7, and an amine liquid circulation pump unit connected in sequence through pipelines; the low-pressure lean liquid pump unit and the amine liquid circulation pump unit have the same pump switching system, which includes a first pump switching pipeline and a second pump switching pipeline connected in parallel, and the amine liquid pre-filter unit includes a first filter switching pipeline and a second filter switching pipeline connected in parallel.

[0043] Specifically, along the direction of medium flow, the first pump switching pipeline is sequentially connected to a first automatic control valve 12, a first first remote pressure gauge 10, a first pump, a second automatic control valve 11, a second first remote pressure gauge 10, and a third automatic control valve 8. The second pump switching pipeline is sequentially connected to a fourth automatic control valve 17, a first second remote pressure gauge 16, a second pump, a fifth automatic control valve 15, a second second remote pressure gauge 16, and a sixth automatic control valve 13. The first pump switching pipeline is connected to a first pump return line, which is connected to the outlet pipeline of the first pump. The first pump return line is connected to a seventh automatic control valve 9. The second pump switching pipeline is connected to a second pump return line, which is connected to the outlet pipeline of the second pump. The second pump return line is connected to an eighth automatic control valve 14. A ninth automatic control valve 18 is connected to the outlet manifold of the first and second pump switching pipelines.

[0044] Specifically, the first filter switching pipeline is sequentially connected to the tenth automatic control valve 19, the first pre-filter, and the eleventh automatic control valve 21, and the first pre-filter is connected to the first differential pressure gauge 20. The second filter switching pipeline is sequentially connected to the twelfth automatic control valve 22, the second pre-filter, and the thirteenth automatic control valve 24, and the second pre-filter is connected to the second differential pressure gauge 23.

[0045] The invention also includes a filter bypass, one end of which is connected to the pipeline between the amine pre-filter 5 and the activated carbon filter 6, and the other end of which is connected between the amine post-filter 7 and the amine circulation pump 4. A fourteenth automatic control valve 25 is connected to the filter bypass, a fifteenth automatic control valve 26 is connected to the inlet pipeline of the activated carbon filter 6, a third differential pressure gauge 29 is connected to the activated carbon filter 6, a sixteenth automatic control valve 28 is connected to the outlet pipeline of the amine post-filter 7, and a fourth differential pressure gauge 27 is connected to the amine post-filter 7.

[0046] The continuously operating amine solution recycling method of this embodiment includes the following steps:

[0047] This invention describes in detail the amine liquid circulation system with two-stage pressurization (i.e., a low-pressure lean liquid pump 3 and an amine liquid circulation pump 4 are provided as an example). The principle of the single-stage pressurization amine liquid circulation system (i.e., only an amine liquid circulation pump 4 is provided) is the same.

[0048] Lean amine solution flows from the bottom of the regeneration tower to the lean-rich solution heat exchanger 1. By optimizing the selection and piping layout of the lean-rich solution heat exchanger 1, the risk of leakage caused by pipeline stress is reduced, ensuring stable and reliable equipment operation. After heat exchange, the lean solution enters the low-pressure lean solution pump 3 for pressurization and then enters the lean solution cooler 2. Shut-off valves are installed at the inlet and outlet of the tube bundle in the lean solution cooler 2. When tube bundle leakage or other problems occur, only the problematic tube bundle is inspected and repaired, improving the flexibility of equipment maintenance. The shut-off valves and piping layout at the inlet and outlet of the lean solution cooler 2 are optimized to both evenly distribute the tube bundle flow and facilitate operation. The lean solution cooler 2 is equipped with remote start / stop and fault detection, linked to a closed-circuit television monitoring system with cameras to monitor on-site operation and improve personnel and equipment safety. After cooling, the lean solution sequentially enters the amine pre-filter 5, activated carbon filter 6, and amine post-filter 7; among which, activated carbon filter 6 and amine post-filter 7 are partial filters. If, during operation, the filter cartridges of the amine pre-filter 5, activated carbon filter 6, and amine post-filter 7 become clogged, causing differential pressure alarms in the first differential pressure gauge 20, second differential pressure gauge 23, third differential pressure gauge 29, and fourth differential pressure gauge 27, the automatic control valves at the filter inlet and outlet can be remotely controlled to quickly switch to the backup filter or bypass line. The filtered lean solution then enters the amine circulation pump 4, is pressurized, and enters the absorption tower.

[0049] In the specific implementation process, the low-pressure lean liquid pump 3 and the amine liquid circulation pump 4 can be set up individually or separately according to the working conditions.

[0050] The lean and rich liquid heat exchanger 1 can be a shell-and-tube heat exchanger, a plate heat exchanger, or other types of heat exchangers.

[0051] The lean liquid cooler 2 can be replaced by a shell-and-tube heat exchanger, a plate heat exchanger, or other types of heat exchangers, or a combination of multiple cooling methods.

[0052] Pump outlet return lines can be set individually for each pump, or they can be set only on the manifold depending on the pump's power.

[0053] I. Detailed description of pump setting automatic start switching:

[0054] This invention describes in detail the amine liquid circulation system with two-stage pressurization (i.e., a low-pressure lean liquid pump 3 and an amine liquid circulation pump 4 are provided as an example). The principle of the single-stage pressurization amine liquid circulation system (i.e., only an amine liquid circulation pump 4 is provided) is the same.

[0055] This invention uses a pump configuration of one operating pump and one standby pump, where the first pump in the accompanying drawings is the pump currently in operation and the second pump is the standby pump, as an example for detailed description. The principle is the same for multiple operating pumps with one standby pump.

[0056] Driving conditions:

[0057] To meet the installation requirements of the amine liquid booster pump, the amine regeneration tower is installed at a higher height than the pump. Through optimized equipment and piping layout, the inlet pipeline of the amine liquid booster pump meets the requirements of the automatic tank pump. After the amine system establishes its liquid level, the amine liquid booster pump is switched to remote control according to the preset control logic, and then remote startup begins. See the pump process flow diagram below. Figure 2 The control logic when the third automatic control valve 8 at the outlet of the amine liquid booster pump is fully closed is as follows: Control of the amine liquid booster pump: First, open the second automatic control valve 11, then open the first automatic control valve 12 to achieve automatic pumping. After the automatic pumping is completed, the amine liquid booster pump is remotely started. The seventh automatic control valve 9 on the return line of the amine liquid booster pump automatically controls the return flow. When the amine liquid booster pump is fully started, the third automatic control valve 8 is remotely opened.

[0058] The automatic venting of the amine liquid booster pump can be achieved by using the second automatic control valve 11 at the top of the pump or by setting up other high-point venting valves separately according to the layout of the pump outlet pipeline.

[0059] After the amine liquid booster pump stabilizes, the amine liquid circulation pump 4 is started. Following the preset control logic, the amine liquid circulation pump 4 is switched to remote control, and then remote startup begins. See the pump process flow diagram below. Figure 2 The control logic when the third automatic control valve 8 at the outlet of the amine circulation pump 4 is fully closed is as follows: First, open the second automatic control valve 11, then open the first automatic control valve 12, using the pressure head of the amine booster pump to achieve automatic pumping of the amine circulation pump 4. After the automatic pumping is completed, the amine circulation pump 4 is remotely started. The seventh automatic control valve 9 on the return line of the amine circulation pump 4 automatically controls the return flow. When the amine circulation pump 4 is fully started, the third automatic control valve 8 at the outlet of the amine circulation pump 4 is remotely opened.

[0060] The third automatic control valve 8 at the outlet of the amine circulation pump 4 can be preset to fully open, partially open, or fully closed states for automatic start-up based on the pump motor selection. The seventh automatic control valve 9 on the pump return line matches the valve status on the outlet pipeline of the amine circulation pump 4 and automatically presets the valve to the corresponding opening degree. Automatic venting of the amine circulation pump 4 can be achieved using the second automatic control valve 11 at the top of the pump or by separately installing other high-point venting valves according to the pump outlet pipeline layout.

[0061] When the amine circulation pump 4 is started with the valve fully open, but the motor selection does not match the pump flow rate, the valve opening of the ninth automatic control valve 18 on the pump outlet manifold can be preset to control the flow rate to meet the current required for motor startup. After a delay, the ninth automatic control valve 18 is switched to automatic control. The same control method can be used for pumps in single-stage pressurized amine circulation systems.

[0062] After the pump is running normally, switch to automatic mode.

[0063] Automatic restart switching under fault conditions:

[0064] See the pump process flow diagram. Figure 2 The description takes the first pump as the pump in operation and the second pump as the standby pump, and takes the third automatic control valve 8 of the second pump being fully closed as an example.

[0065] When the first pump experiences abnormal signals such as vibration, temperature, pressure, outlet flow, or operating status, it will shut down immediately, and the second pump will automatically start according to the control logic. The eighth automatic control valve 14 on the return line of the second pump automatically controls the return flow. Once the pump is fully started, the sixth automatic control valve 13 at the pump outlet will automatically open.

[0066] The sixth automatic control valve 13 at the outlet of the second pump is preset to fully open, partially open, and fully closed states for automatic start-up based on the pump motor selection. The eighth automatic control valve 14 on the pump return line matches the valve status on the outlet pipeline of the second pump and automatically presets the valve to the corresponding opening degree. Automatic venting of the second pump can be achieved using the fifth automatic control valve 15 at the top of the pump or by separately installing other high-point venting valves according to the layout of the pump outlet pipeline.

[0067] When the shut-off valve of the outlet pipeline of the amine circulation pump 4 is a fully open manual valve, but the motor selection does not match the pump flow rate, the valve opening of the ninth automatic control valve 18 on the pump outlet manifold needs to be preset to control the flow rate to meet the current during motor startup. After a delay, the ninth automatic control valve 18 is switched to automatic control. The same control can be used for pumps in single-stage pressurized amine circulation systems.

[0068] Figure 2In this system, the pump outlet pipeline is equipped with a single check valve or two different types of check valves to protect the pump instantly when it stops; the pump stop signal simultaneously triggers the automatic control valve on the outlet pipeline to close, thus protecting the pump after it stops.

[0069] When the system adopts a two-stage pressurized amine liquid circulation system (i.e., setting a low-pressure lean liquid pump 3 and an amine liquid circulation pump 4), the equipment selection or pipeline layout of the amine liquid pressurization pump and the amine liquid circulation pump 4 need to be optimized to ensure that the amine liquid circulation pump 4 will not be shut down during the instantaneous start-up switching of the amine liquid pressurization pump.

[0070] Manual remote switching:

[0071] See the pump process flow diagram. Figure 2 The following description uses the example of the first pump in the attached diagram being the pump in operation and the second pump being the standby pump.

[0072] When periodic maintenance of the pumps is required, a remote pump switching command is given. The second pump will, according to preset logic, first open the fifth automatic shut-off valve at the high point of the second pump outlet to vent air. At the same time, the sixth automatic control valve 13 at the outlet of the second pump and the eighth automatic control valve 14 on the return pipeline are preset with their valve positions according to the pump motor selection. Then, the second pump starts. The first pump, according to preset logic, stops after the second pump starts and runs normally, and then automatically closes the third automatic control valve 8 on the outlet pipeline of the first pump.

[0073] In practice, the pump can be automatically vented by using the second automatic control valve 11 and the fifth automatic control valve 15 at the top of the pump, or by setting other high-point venting valves separately according to the layout of the pump outlet pipeline.

[0074] 2. Select appropriate lean and rich liquid heat exchangers 1, optimize pipeline layout, reduce the risk of leakage caused by pipeline stress, and achieve stable and reliable operation.

[0075] 3. Shut-off valves are installed at the inlet and outlet of the lean liquid cooler 2. In case of tube leakage or other problems, only the problematic tube will be inspected and repaired, improving the flexibility of equipment maintenance. In addition, the air cooler is equipped with remote start / stop functionality and a closed-circuit television monitoring system linked to cameras to monitor on-site operation and improve the safety of personnel and equipment.

[0076] IV. Automatic control valves are installed at the inlet and outlet of the amine solution filtration system to achieve automatic switching. See [link / details]. Figure 3 The filter process flow.

[0077] For the amine pre-filter 5, the first pre-filter is the operating filter, and the second pre-filter is the standby filter. When the filter element of the first pre-filter causes a differential pressure alarm due to blockage, or when the blockage causes overpressure, the system automatically switches to the second pre-filter.

[0078] For activated carbon filter 6 and amine liquid post-filter 7, when the filter element is clogged and causes a differential pressure alarm on the third differential pressure gauge 29 or the fourth differential pressure gauge 27, resulting in overpressure, the filter will automatically switch to bypass.

[0079] This invention incorporates safety protection measures to ensure the safety of the pump and its maintenance processes. A closed-circuit television monitoring system linked to cameras is installed to monitor on-site operation, reducing on-site personnel workload while monitoring equipment operation and improving personnel and equipment safety. The on-site control column is equipped with a pump locking function to prevent the pump from automatically starting during on-site maintenance, ensuring operator safety. The pump motor is equipped with current protection facilities to prevent current overload during automatic start-up. Vibration, temperature, and pressure monitoring instruments are installed on the pump body and its auxiliary facilities for routine monitoring to ensure safe pump operation.

[0080] The pump of this invention employs self-starting technology, enhancing the stability and safety of uninterrupted system operation from multiple aspects, including start-up, normal operation and maintenance, emergency switching, and safety protection measures. When the operating pump fails and stops, the standby pump is immediately started automatically through control logic. This invention includes a periodic switching function to ensure routine pump maintenance. It also features an automatic venting function. Shut-off valves are installed at the inlet and outlet of the air cooler tube bundle; if a tube bundle leak occurs, only the problematic tube bundle can be inspected and repaired, improving the flexibility of equipment maintenance. The inlet and outlet shut-off valves and piping layout of the lean liquid cooler 2 are optimized to both evenly distribute the tube bundle flow and facilitate operation. The amine liquid filter uses automatic switching; when a differential pressure alarm is triggered due to filter element blockage, remote operation automatically switches to the standby filter or bypass. This invention incorporates a fault and closed-circuit television monitoring system linked camera function to monitor on-site operation, reducing the frequency of on-site personnel work while monitoring equipment operation, thus improving the safety of personnel and equipment. The pump's on-site operation column has a pump lock function to ensure that the pump does not self-start during on-site maintenance, further ensuring operator safety.

[0081] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A continuously operating amine liquid circulation system, characterized in that: The system includes a lean and rich liquid heat exchanger (1), a low-pressure lean liquid pump unit, a lean liquid cooler (2), an amine liquid pre-filter unit, an activated carbon filter (6), an amine liquid post-filter (7), and an amine liquid circulation pump unit, which are connected in sequence via pipelines. The low-pressure lean liquid pump unit and the amine liquid circulation pump unit have the same pump switching system, which includes a first pump switching pipeline and a second pump switching pipeline connected in parallel. The amine liquid pre-filter unit includes a first filter switching pipeline and a second filter switching pipeline connected in parallel.

2. The continuously operating amine liquid circulation system according to claim 1, characterized in that: Along the direction of medium flow, the first pump switching pipeline is sequentially connected to the first automatic control valve (12), the first first remote pressure gauge (10), the first pump, the second automatic control valve (11), the second first remote pressure gauge (10), and the third automatic control valve (8). The second pump switching pipeline is sequentially connected to the fourth automatic control valve (17), the first second remote pressure gauge (16), the second pump, the fifth automatic control valve (15), the second second remote pressure gauge (16), and the sixth automatic control valve (13). The first pump switching pipeline is connected to the first pump return line, which is connected to the outlet pipeline of the first pump. The first pump return line is connected to the seventh automatic control valve (9). The second pump switching pipeline is connected to the second pump return line, which is connected to the outlet pipeline of the second pump. The second pump return line is connected to the eighth automatic control valve (14). The outlet manifold of the first pump switching pipeline and the second pump switching pipeline is connected to the ninth automatic control valve (18).

3. The continuously operating amine liquid circulation system according to claim 2, characterized in that: The first filter switching pipeline is connected in sequence to the tenth automatic control valve (19), the first pre-filter, and the eleventh automatic control valve (21). The first pre-filter is connected to the first differential pressure gauge (20). The second filter switching pipeline is connected in sequence to the twelfth automatic control valve (22), the second pre-filter, and the thirteenth automatic control valve (24). The second pre-filter is connected to the second differential pressure gauge (23).

4. The continuously operating amine liquid circulation system according to claim 3, characterized in that: It also includes a filter bypass, one end of which is connected to the pipeline between the amine pre-filter (5) and the activated carbon filter (6), and the other end of which is connected between the amine post-filter (7) and the amine circulation pump (4).

5. The continuously operating amine liquid circulation system according to claim 4, characterized in that: The filter bypass is connected to the fourteenth automatic control valve (25), the inlet pipe of the activated carbon filter (6) is connected to the fifteenth automatic control valve (26), the activated carbon filter (6) is connected to the third differential pressure gauge (29), the outlet pipe of the amine liquid post-filter (7) is connected to the sixteenth automatic control valve (28), and the amine liquid post-filter (7) is connected to the fourth differential pressure gauge (27).

6. The continuously operating amine liquid circulation system according to claim 1, characterized in that: The tube bundle inlet and outlet of the lean liquid cooler (2) is equipped with shut-off valves.

7. The continuously operating amine liquid circulation system according to claim 1, characterized in that: It also includes a closed-circuit television monitoring system for remotely starting and stopping the lean liquid cooler (2) and for monitoring the amine liquid circulation system for faults.

8. The continuously operating amine liquid circulation system according to claim 1, characterized in that: The lean and rich liquid heat exchanger (1) is a shell-and-tube heat exchanger or a plate heat exchanger; the lean liquid cooler (2) is replaced by an air cooler shell-and-tube heat exchanger or a plate heat exchanger.

9. A continuously operating amine liquid circulation method, using the continuously operating amine liquid circulation system according to any one of claims 5 to 8, characterized in that: Includes the following steps: Driving conditions: Control of the amine liquid booster pump: First, open the second automatic control valve (11), then open the first automatic control valve (12); after the automatic tank pump is completed, remotely start the amine liquid booster pump. When the amine liquid booster pump is fully started, remotely open the third automatic control valve (8). The seventh automatic control valve (9) on the return line of the amine liquid booster pump automatically controls the return flow. After the amine liquid booster pump is running stably, the control of the amine liquid circulation pump (4) is as follows: first open the second automatic control valve (11), then open the first automatic control valve (12); after the automatic tank pump is completed, remotely start the amine liquid circulation pump (4); after the amine liquid circulation pump (4) is fully started, remotely open the third automatic control valve (8) at the outlet of the amine liquid circulation pump (4), and the seventh automatic control valve (9) on the return line of the amine liquid circulation pump (4) automatically controls the return flow rate; Automatic restart switching under fault conditions: When the first pump exhibits abnormal signals including vibration, temperature, pressure, outlet flow, and operating status, The first pump stops in an emergency, and the second pump starts automatically according to the control logic. When the second pump starts fully, the sixth automatic control valve (13) at the outlet of the second pump opens automatically, and the eighth automatic control valve (14) on the return line of the second pump automatically controls the return flow. The sixth automatic control valve (13) at the outlet of the second pump is automatically started by presetting the valve to fully open, partially open and fully closed states according to the pump motor selection; the eighth automatic control valve (14) on the return line of the second pump matches the valve status on the outlet pipeline of the second pump and automatically presets the valve to the corresponding opening degree; the fifth automatic control valve (15) is used to control the automatic exhaust of the second pump, or the exhaust valve at the high point is set separately according to the outlet pipeline layout of the second pump for exhaust; When the outlet pipeline shut-off valve of the amine circulation pump (4) is a fully open manual valve, but the motor selection does not match the pump flow rate, the valve position opening of the ninth automatic control valve (18) on the outlet manifold of the amine circulation pump (4) needs to be preset to control the flow rate to meet the current when the motor starts. After a delay, the ninth automatic control valve (18) is switched to automatic control. The outlet pipelines of the first and second pumps are equipped with a single check valve or two check valves of different types; the stop signal of the first and second pumps simultaneously triggers the shut-off of the automatic control valve on the outlet pipeline. Manual remote switching: When the low-pressure lean liquid pump (3) or amine circulation pump (4) needs to be regularly inspected, a switching command is remotely given to the low-pressure lean liquid pump (3) or amine circulation pump (4). The second pump, according to the preset logic, first opens the fifth automatic shut-off valve at the high point of the second pump outlet to exhaust gas. The sixth automatic control valve (13) at the outlet of the second pump and the eighth automatic control valve (14) on the return line of the second pump are preset according to the motor selection of the second pump. Then the second pump starts. The first pump, according to the preset logic, stops when the second pump starts and runs normally, and then automatically closes the third automatic control valve (8) on the outlet pipeline of the first pump. Exhaust gas is vented by using the second automatic control valve (11) and the fifth automatic control valve (15), or by using a high-point exhaust valve separately installed according to the arrangement of the outlet pipes of the first pump and the second pump. When the filter element of the first pre-filter causes the first differential pressure alarm due to blockage, and then causes overpressure due to blockage, it automatically switches to the second pre-filter. For the activated carbon filter (6) and the amine liquid post-filter (7), when the filter element is blocked and causes the third differential pressure gauge (29) or the fourth differential pressure gauge (27) to alarm, resulting in overpressure, the filter will automatically switch to the filter bypass.

10. A continuously operating amine liquid circulation method according to claim 9, characterized in that: When controlling the amine liquid booster pump during operation, the second automatic control valve (11) is used to automatically vent the amine liquid booster pump, or a high-point venting valve is set separately according to the outlet pipeline layout of the amine liquid booster pump to vent the amine liquid booster pump. When controlling the amine circulation pump (4) during operation, the third automatic control valve (8) at the outlet of the amine circulation pump (4) is automatically started by presetting the valve to fully open, partially open, and fully closed states according to the motor selection of the amine circulation pump (4); the seventh automatic control valve (9) on the return line of the amine circulation pump (4) matches the valve status on the outlet pipeline of the amine circulation pump (4) and automatically presets the valve to the corresponding opening degree; the second automatic control valve (11) is used to automatically vent the amine circulation pump (4), or a high-point vent valve is separately set according to the outlet pipeline layout of the amine circulation pump (4) for venting; When the amine circulation pump (4) is started with the valve fully open, but the motor selection does not match the pump flow rate, the valve position of the ninth automatic control valve (18) is preset to control the flow rate to meet the current when the motor starts. After a delay, the ninth automatic control valve (18) is switched to automatic control.

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