Natural gas desulfurization device and control method thereof

Abstract

The application discloses a natural gas desulfurization device and a control method thereof, relates to the technical field of natural gas purification, and comprises a desulfurization absorption tower, a gravity separator, a dehydration absorption tower, a desulfurization regeneration tower and a desulfurization solution low-position tank, wherein a liquid level meter one is connected in the gravity separator, a liquid level meter two is connected in the dehydration absorption tower, and a liquid level meter three is connected in the desulfurization solution low-position tank; the desulfurization solution low-position tank is connected with the gravity separator and the dehydration absorption tower through a solution automatic recovery structure; the desulfurization solution low-position tank is connected with the desulfurization regeneration tower and the desulfurization absorption tower through a solution automatic supplement structure; the desulfurization solution low-position tank is connected with a pressure detection structure; and the signals of the liquid level meter one, the liquid level meter two, the liquid level meter three, the solution automatic recovery structure, the solution automatic supplement structure and the pressure detection structure are all connected to a controller. The solution automatic + quantitative + small-flow recovery and supplement functions are realized, the protection effect of preventing high-pressure leakage into low-pressure is achieved, and the safety risks of endangering equipment and personnel that may occur in the recovery process are eliminated.

Description

Technical Field

[0001] This invention relates to the field of natural gas purification technology, specifically to a natural gas desulfurization device and its control method. Background Technology

[0002] Natural gas purification mainly refers to the process of removing impurities from crude gas to make it suitable for city gas quality requirements. Crude gas generally contains impurities such as dust, naphthalene, tar, water, nitrogen compounds (such as NH, HCN, NO), inorganic sulfur (such as HS), and organic sulfur (such as CS, COS). These impurities can clog pipelines, corrode equipment and appliances, or pollute the environment during combustion, and must be removed. Natural gas desulfurization equipment is required when removing sulfur impurities from natural gas.

[0003] Current natural gas desulfurization (FGD) systems, after the raw natural gas passes through the desulfurization absorption tower, contains a large amount of gaseous desulfurizing agent. This gas then passes through a gravity separator and enters a dehydration tower for dehydration. During this process, the desulfurizing agent is carried away by the natural gas in the liquid separation section of the gravity separator and dehydration tower, resulting in a significant amount being separated and accumulating at the bottom of these systems. This requires manual recovery to a low-level tank, followed by manual replenishment to the FGD system to maintain a stable total amount of desulfurizing agent and ensure effective desulfurization.

[0004] Current desulfurization equipment can only recover and replenish the desulfurizing agent through manual operation. This results in high operation frequency and easy disturbance to the desulfurization system. Moreover, untimely or improper manual recovery and replenishment of the solution can lead to substandard natural gas quality or even accidents such as cross-pressure and interlock shutdown of the desulfurization equipment, causing natural gas to be vented and burned. Summary of the Invention

[0005] The technical problem this invention aims to solve is that current desulfurization devices can only recover and replenish desulfurizing agents through manual operation, which results in high operation frequency and easy disturbance to the desulfurization system. Moreover, untimely or improper manual recovery and replenishment of the solution can lead to substandard natural gas quality or even accidents such as cross-pressure and interlock shutdown of the desulfurization device. The purpose is to provide a natural gas desulfurization device and its control method, which solves the problems of high operation frequency and easy disturbance to the desulfurization system caused by the current desulfurization devices that can only recover and replenish desulfurizing agents through manual operation.

[0006] This invention is achieved through the following technical solution:

[0007] A natural gas desulfurization device includes a desulfurization absorption tower, a gravity separator, a dehydration absorption tower, a desulfurization regeneration tower, and a desulfurization solution low-level tank. A level gauge is connected to the gravity separator, a level gauge is connected to the dehydration absorption tower, and a level gauge is connected to the desulfurization solution low-level tank. An automatic solution recovery structure connects the desulfurization solution low-level tank to the gravity separator and the dehydration absorption tower. An automatic solution replenishment structure connects the desulfurization solution low-level tank to the desulfurization regeneration tower and the desulfurization absorption tower. A pressure detection structure is connected to the desulfurization solution low-level tank. The signals from level gauges 1, 2, and 3, the automatic solution recovery structure, the automatic solution replenishment structure, and the pressure detection structure are all connected to a controller.

[0008] By connecting level gauge 1, level gauge 2, level gauge 3, the automatic recovery structure, and the automatic replenishment structure to a controller (which can be a system or controller with control functions, such as a PLC, RTU, DCS, or SIS), not only is the liquid level in the gravity separator, dehydration absorption tower, and desulfurization solution low-level tank monitored, but the automatic recovery and replenishment of the desulfurization solution is also realized. This keeps the solution in the gravity separator, desulfurization regeneration tower, dehydration absorption tower, and desulfurization solution low-level tank in dynamic equilibrium. Furthermore, the connected pressure detection structure provides protection against high pressure escalation to low pressure, eliminating potential safety risks to equipment and personnel during the solution recovery process.

[0009] Furthermore, the automatic solution recovery structure includes a reflux pipe connected between the desulfurization solution low-level tank and the dehydration absorption tower and gravity separator; an automatic shut-off valve one is connected to the reflux pipe connected to the gravity separator, and an automatic shut-off valve two is connected to the reflux pipe connected to the dehydration absorption tower; the signals of the automatic shut-off valve one and the automatic shut-off valve two are both connected to the controller.

[0010] Furthermore, both the return pipe connected to the gravity separator and the return pipe connected to the dewatering absorption tower are connected to a main sewage discharge pipe, and both are equipped with manual valves.

[0011] Furthermore, two manual valves are connected to the return pipes of the automatic shut-off valve one and the automatic shut-off valve two respectively; a flow limiting orifice plate one is connected to the return pipe between the automatic shut-off valve one and the manual valves; and a flow limiting orifice plate two is connected to the return pipe between the automatic shut-off valve two and the manual valves.

[0012] The automatic solution recovery structure enables quantitative and low-flow-rate automatic solution recovery, minimizing the impact on the operation of the gravity separator and dehydration absorption tower, thus ensuring the stable operation of the desulfurization unit. At the same time, the connected limiting orifice plate one and flow limiting orifice plate two can limit the flow rate and reduce the pressure, greatly reducing the impact of the desulfurization solution flowing between different devices within the unit.

[0013] Furthermore, the automatic solution replenishment structure includes a solution replenishment pipe connected between the desulfurization solution low-level tank and the desulfurization regeneration tower and desulfurization absorption tower; an automatic shut-off valve three and a one-way valve one are connected to the solution replenishment pipe connected to the desulfurization regeneration tower, and a flow-limiting orifice plate three is connected between the automatic shut-off valve three and the one-way valve one; an automatic shut-off valve four and a one-way valve two are connected to the solution replenishment pipe connected to the desulfurization absorption tower; a starting pump is connected to the connection between the solution replenishment pipe and the desulfurization solution low-level tank; at least one solution pump is connected to the solution replenishment pipe connected to the desulfurization absorption tower; and the signals of the automatic shut-off valve three, the automatic shut-off valve four, the starting pump, and the solution pump are all connected to the controller.

[0014] Furthermore, a branch pipe is connected to the solution replenishment pipe connected to the desulfurization absorption tower, and a manual valve is connected to the branch pipe, which is connected to the solution storage tank.

[0015] Furthermore, a regulating valve is connected between the automatic shut-off valve four and the single-phase valve two, and a manual valve is connected between the regulating valve and the automatic shut-off valve four, and a manual valve is also connected between the regulating valve and the single-phase valve two; a branch pipe is connected to both ends of the regulating valve, one end of the branch pipe is connected to the solution replenishment pipe between the single-phase valve and the manual valve, and the other end is connected to the solution replenishment pipe between the automatic shut-off valve four and another manual valve; a manual valve is also connected to the branch pipe.

[0016] Furthermore, a connecting pipe for connecting a desulfurization flash tank is connected to the solution replenishment pipe connected to the desulfurization absorption tower, and a control valve is connected to the connecting pipe.

[0017] The automatic solution replenishment structure can automatically replenish the desulfurization unit to the regeneration tower in a quantitative and small-flow manner during operation. During start-up or in case of abnormalities, a large flow of replenishment solution can be pumped into the desulfurization absorption tower, ensuring both stable operation of the unit and meeting the unit's need for large-flow replenishment. The regeneration tower is the device for regenerating the desulfurization solution. The automatic solution replenishment structure has a smaller impact on the amount of solution entering the regeneration tower, thus minimizing its impact on the tower's operation. The outlet of the solution pump connects to both the desulfurization absorption tower and the desulfurization flash tank. Connecting the pump to the inlet with replenishment solution does not affect the outlet flow rate, and therefore does not affect the desulfurization effect of the absorption tower on natural gas or the flash vapor from the flash tank gas column. Furthermore, this replenishment method does not affect the pump's circulation rate, thus having no impact on the operation of the absorption tower and flash tower.

[0018] During production, desulfurization equipment requires continuous replenishment of solution at a small flow rate to reduce the impact on the system. However, during start-up, it requires rapid replenishment of solution at a large flow rate to save time and improve work efficiency. The desulfurization equipment of this application can switch between the two replenishment methods of large and small flow rates by connecting a regulating valve, so as to meet the adjustment needs of the solution replenishment flow rate in the entire equipment at different times and operating conditions.

[0019] Furthermore, the pressure detection structure includes a nitrogen water seal tank and a pressure transmitter for pressure measurement. The pressure transmitter is installed on the pipeline connecting the nitrogen water seal pipe and the desulfurization solution low-level tank, and the signal of the pressure transmitter is connected to the controller.

[0020] To achieve the above objectives, this application also proposes a control method for a natural gas desulfurization device.

[0021] The control method employs automatic, quantitative, and low-flow-rate operation.

[0022] The automatic control method for the solution to enter the desulfurization solution low-level tank from the gravity separator is as follows: the liquid level in the gravity separator is detected by the liquid level gauge. When the liquid level is higher than the set high alarm value and the pressure in the desulfurization solution low-level tank is lower than the set high alarm value, the controller automatically opens the automatic shut-off valve and alarms. When the liquid level is lower than the set low alarm value or the pressure is higher than the set high alarm value, the controller automatically closes the automatic shut-off valve.

[0023] The automatic control method for the solution to enter the desulfurization solution low-level tank from the dehydration absorption tower is as follows: the liquid level in the dehydration absorption tower is detected by level gauge 2. When the liquid level is higher than the set high alarm value, and the pressure value of the desulfurization solution low-level tank is lower than the set high alarm value and the liquid level of the gravity separator is lower than the set high alarm value, the controller automatically opens automatic shut-off valve 2 to perform desulfurization solution recovery operation; during the recovery process, when the liquid level is lower than the set low alarm value or the pressure value is higher than the set high alarm value, the controller automatically closes automatic shut-off valve 2.

[0024] The automatic control method for replenishing the desulfurization regeneration tower and desulfurization absorption tower solution is as follows: The level gauge three detects the liquid level in the low-level desulfurization solution tank. When the liquid level exceeds the high alarm value, the controller automatically starts the start pump and opens the automatic shut-off valve three, automatically replenishing the solution in the low-level desulfurization solution tank to the desulfurization regeneration tower. During the automatic replenishment process, when the liquid level in the low-level desulfurization solution tank exceeds the set high alarm value, the automatic shut-off valve four automatically opens, and the regulating valve opens simultaneously. When the liquid level in the low-level desulfurization solution tank falls below the set low alarm value, the automatic shut-off valves three and four, and the regulating valve, are simultaneously closed, thus achieving automatic replenishment of solution from the low-level desulfurization solution tank to the desulfurization unit.

[0025] The solution recovery and replenishment are controlled quantitatively and at low flow rates by connecting flow-limiting orifice plate one, flow-limiting orifice plate two, and flow-limiting orifice plate three.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] (1) By connecting level gauge 1, level gauge 2, level gauge 3, automatic recovery structure and automatic replenishment structure to the controller, it not only realizes the monitoring of the liquid level in the gravity separator, dehydration absorption tower and desulfurization solution low-level tank, but also realizes the automatic recovery and replenishment of desulfurization solution, so that the solution in the gravity separator, desulfurization regeneration tower, dehydration absorption tower and desulfurization solution low-level tank is in dynamic equilibrium, and the connected pressure detection structure plays a protective role against high pressure crossing low pressure, eliminating the safety risks that may occur to equipment and personnel during the solution recovery process;

[0028] (2) The automatic solution recovery structure can realize the automatic recovery of solution in a quantitative and small flow rate, which has little impact on the operation of gravity separator and dehydration absorption tower, ensuring the stable operation of desulfurization unit. At the same time, the connected limiting orifice plate can limit the flow rate and reduce the pressure, greatly reducing the impact of desulfurization solution flow between different equipment in the unit.

[0029] (3) The automatic solution replenishment structure can automatically replenish the solution to the regeneration tower in a quantitative and small-flow manner during the operation of the desulfurization unit. During the start-up period or in case of an anomaly, a large-flow replenishment can be made by pumping the solution into the desulfurization absorption tower, ensuring both stable operation of the unit and meeting the unit's need for large-flow solution replenishment. The regeneration tower is the equipment for reviving and regenerating the desulfurization solution. The automatic solution replenishment structure has a smaller impact on the amount of solution entering the desulfurization regeneration tower. Therefore, it has a smaller impact on the operation of the desulfurization regeneration tower. The outlet of the solution pump is connected to the desulfurization absorption tower and the desulfurization flash tank. Connecting the replenishment solution to its inlet will not affect the outlet flow rate, thus not affecting the desulfurization effect of the desulfurization absorption tower on natural gas and the desulfurization flash tank gas column on flash vapor. Furthermore, this replenishment method does not affect the circulation rate of the solution pump, therefore it has no impact on the operation of the desulfurization absorption tower and the flash tower.

[0030] (4) During production, the desulfurization unit needs to continuously replenish the solution at a small flow rate to reduce the impact on the system, while during start-up, it needs to replenish the solution at a large flow rate to save time and improve work efficiency. The desulfurization unit of this application can switch between the two replenishment methods of large flow rate and small flow rate by connecting the regulating valve, so as to meet the adjustment needs of the solution replenishment flow rate in the whole unit at different times and working conditions. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0032] Figure 1 This is a schematic diagram of the structure of a natural gas desulfurization device in Embodiment 1 of the present invention;

[0033] Figure 2 for Figure 1 Enlarged view of A in the middle;

[0034] Figure 3 This is a partial structural schematic diagram of a natural gas desulfurization device in Embodiment 2 of the present invention;

[0035] Figure 4 This is a partial structural schematic diagram of a natural gas desulfurization device in Embodiment 3 of the present invention;

[0036] Figure 5 This is a partial structural schematic diagram of a natural gas desulfurization device in Embodiment 4 of the present invention;

[0037] Figure 6 The control flowcharts for Embodiments 1 to 4 of this invention are shown below;

[0038] Figure 7 The following are the automatic valve opening operation logic diagrams for Embodiments 1 to 4 of this invention;

[0039] Figure 8 This is a logic diagram of the automatic valve closing action in Embodiments 1 to 4 of the present invention.

[0040] The attached diagram shows the markings and corresponding component names:

[0041] 11-Desulfurization regeneration tower, 12-Automatic shut-off valve three, 13-Check valve one, 14-Check valve two, 15-Solution pump, 16-Automatic shut-off valve one, 17-Desulfurization absorption tower, 18-Level gauge one, 19-Desulfurization flash tank, 21-Gravity separator, 22-Dehydration absorption tower, 23-Level gauge two, 24-Automatic shut-off valve two, 25-Flow limiting orifice plate, 26-Sewage main pipe, 27-Return pipe, 28-Nitrogen water seal tank, 29-Pressure transmitter, 31-Level gauge three, 32-Desulfurization solution low-level tank, 33-Solution replenishment pipe, 34-Starting pump, 35-Automatic shut-off valve four, 36-Regulating valve, 37-Branch pipe, 38-Solution storage tank, 39-Flow limiting orifice plate two, 40-Flow limiting orifice plate three. Detailed Implementation

[0042] 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.

[0043] 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.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, a joint, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] Example 1

[0047] Reference Figure 1 and Figure 2 This embodiment provides a natural gas desulfurization device, including a desulfurization absorption tower 17, a gravity separator 21, a dehydration absorption tower 22, a desulfurization regeneration tower 11, and a desulfurization solution low-level tank 32. A level gauge 18 is connected to the gravity separator 21, a level gauge 23 is connected to the dehydration absorption tower 22, and a level gauge 31 is connected to the desulfurization solution low-level tank 32.

[0048] An automatic solution recovery structure is connected between the desulfurization solution low-level tank 32, the gravity separator 21, and the dehydration absorption tower 22. This structure includes a return pipe 27 connecting the desulfurization solution low-level tank 32, the dehydration absorption tower 22, and the gravity separator 21. An automatic shut-off valve 16 is connected to the return pipe 27 connected to the gravity separator 21, and an automatic shut-off valve 24 is connected to the return pipe 27 connected to the dehydration absorption tower 22. Both the automatic shut-off valve 16 and the automatic shut-off valve 24 communicate with a PLC controller. Connections; two manual valves are connected to the return pipe 27, which is connected to the automatic shut-off valve 16 and the automatic shut-off valve 24 respectively; a flow limiting orifice plate 25 is connected to the return pipe 27 between the automatic shut-off valve 16 and the manual valve; a flow limiting orifice plate 39 is connected to the return pipe 27 between the automatic shut-off valve 24 and the manual valve; a main sewage pipe 26 is connected to the return pipe 27 connected to the gravity separator 21 and the return pipe 27 connected to the dewatering absorption tower 22, and a manual valve is connected to the main sewage pipe 26.

[0049] An automatic solution replenishment structure is connected between the desulfurization solution low-level tank 32 and the desulfurization regeneration tower 11 and the desulfurization absorption tower 17. This structure includes a solution replenishment pipe 33 connecting the desulfurization solution low-level tank 32 and the desulfurization regeneration tower 11 and the desulfurization absorption tower 17. An automatic shut-off valve 32 and a one-way valve 13 are connected to the solution replenishment pipe 33 connected to the desulfurization regeneration tower 11. A flow-limiting orifice plate 40 is connected between the automatic shut-off valve 32 and the one-way valve 13. An automatic shut-off valve 45 and a one-way valve 2 are connected to the solution replenishment pipe 33 connected to the desulfurization absorption tower 17. A starter pump 34 is connected to the connection between the solution replenishment pipe 33 and the desulfurization solution low-level tank 32. A solution pump 15 is connected to the solution replenishment pipe 33 connected to the desulfurization absorption tower 17. The signals from the automatic shut-off valve 32, the automatic shut-off valve 4, the starter pump 34, and the solution pump 15 are all connected to a controller.

[0050] A connection pipe for connecting to the desulfurization flash tank 19 is connected to the solution replenishment pipe 33 connected to the desulfurization absorption tower 17, and a control valve is connected to the connection pipe.

[0051] The desulfurization solution low-level tank 32 is connected to a pressure detection structure, including a nitrogen water seal tank 28. A pressure transmitter 29 is connected to the pipeline connecting the nitrogen water seal pipe and the desulfurization solution low-level tank 32. The pressure transmitter 29 is communicatively connected to the controller.

[0052] Reference Figure 6-8 The control method for the above-mentioned natural gas desulfurization device is: to adopt an automatic, quantitative, and low-flow control method;

[0053] (1) The control method for automatically controlling the solution to enter the desulfurization solution low-level tank 32 from the gravity separator 21 is as follows: the liquid level value in the gravity separator 21 is detected by the liquid level gauge 18. When the liquid level is higher than the set high alarm value and the pressure value in the desulfurization solution low-level tank 32 is lower than the set high alarm value, the controller automatically opens the automatic shut-off valve 16 and alarms; when the liquid level is lower than the set low alarm value or the pressure value is higher than the set high alarm value, the controller automatically closes the automatic shut-off valve 16.

[0054] (2) The control method for automatically controlling the solution to enter the desulfurization solution low-level tank 32 from the dehydration absorption tower 22 is as follows: the liquid level value in the dehydration absorption tower 22 is detected by the liquid level gauge 23. When the liquid level is higher than the set high alarm value and the pressure value of the desulfurization solution low-level tank 32 is lower than the set high alarm value, the controller automatically opens the automatic shut-off valve 24 to perform the desulfurization solution recovery operation; during the recovery process, when the liquid level is lower than the set low alarm value or the pressure value is higher than the set high alarm value, the controller automatically closes the automatic shut-off valve 24.

[0055] (3) The method for automatically replenishing the solution in the desulfurization regeneration tower 11 and the desulfurization absorption tower 17 is as follows: The liquid level in the low-level tank 32 of the desulfurization solution is detected by the level gauge 31. When the liquid level is higher than the high alarm value, the controller automatically starts the start pump 34 and opens the automatic shut-off valve 312 to automatically replenish the solution in the low-level tank 32 of the desulfurization solution to the desulfurization regeneration tower 11. During the automatic replenishment process, when the liquid level in the low-level tank 32 of the desulfurization solution is higher than the set high alarm value, the automatic shut-off valve 45 is automatically opened and the regulating valve 36 is opened at the same time. When the liquid level in the low-level tank 32 of the desulfurization solution is lower than the set low alarm value, the automatic shut-off valve 24 is automatically opened and the automatic shut-off valve 312, the automatic shut-off valve 45 and the regulating valve 36 are closed at the same time to realize the automatic recovery of the solution from the dehydration absorption tower 22.

[0056] The solution can be quantitatively controlled and the flow rate can be controlled by connecting the flow-limiting orifice plate 25, flow-limiting orifice plate 39, and flow-limiting orifice plate 40.

[0057] The automatic solution recovery structure enables quantitative and low-flow-rate automatic solution recovery, minimizing the impact on the operation of gravity separator 21 and dehydration absorption tower 22, thus ensuring the stable operation of the desulfurization unit. At the same time, the connected limiting orifice plate 25 can limit the flow rate and reduce the pressure, greatly reducing the impact of the desulfurization solution flowing between different devices within the unit.

[0058] The automatic solution replenishment structure can automatically replenish the solution to the desulfurization regeneration tower 11 in a quantitative and small-flow manner during the operation of the desulfurization unit. During start-up or in case of abnormalities, a large flow of replenishment solution can be introduced into the desulfurization absorption tower via the solution pump 15. This ensures both stable operation of the unit and meets the unit's need for large-flow replenishment solution. The desulfurization regeneration tower 11 is the device for regenerating the desulfurization solution. The automatic solution replenishment structure has a smaller impact on the amount of solution entering the desulfurization regeneration tower 11, thus having a smaller impact on its operation. The outlet of the solution pump 15 connects to the desulfurization absorption tower and the desulfurization flash tank 19. The amount of replenishment solution entering its inlet does not affect its outlet flow rate, and therefore does not affect the desulfurization effect of the desulfurization absorption tower 17 on natural gas or the desulfurization flash tank 19 on flash vapor. Furthermore, this replenishment method does not affect the circulation rate of the solution pump 15, and therefore has no impact on the operation of the desulfurization absorption tower 17 and the desulfurization flash tank 19.

[0059] Example 2

[0060] Reference Figure 3 The difference between this embodiment and embodiment 1 is that in this embodiment, an adjusting valve 36 is connected between the automatic shut-off valve 4 35 and the single-phase valve 2, and a manual valve is connected between the adjusting valve 36 and the automatic shut-off valve 4 35. A manual valve is also connected between the adjusting valve 36 and the single-phase valve 2. Branch pipes are connected to both ends of the adjusting valve 36. One end of the branch pipe is connected to the solution replenishment pipe 33 between the single-phase valve and the manual valve, and the other end is connected to the solution replenishment pipe 33 between the automatic shut-off valve 4 35 and another manual valve. A manual valve is also connected to the branch pipe.

[0061] The aforementioned added technical features enable the automatic solution replenishment structure to automatically replenish the solution to the regeneration tower in a quantitative and low-flow manner. The flow rate of the replenished solution entering the solution pump 15 can be adjusted, ensuring stable operation of the device. The regeneration tower is the equipment for regenerating the desulfurization solution. The automatic solution replenishment structure has a smaller impact on the amount of solution entering the desulfurization regeneration tower 11, thus having a smaller impact on the operation of the desulfurization regeneration tower 11.

[0062] Example 3

[0063] Reference Figure 4 The difference between this embodiment and embodiment 2 is that in this embodiment, a branch pipe 37 is connected to the solution replenishment pipe 33 connected to the desulfurization absorption tower 17, a manual valve is connected to the branch pipe 37, and the branch pipe 37 is connected to the solution storage tank 38.

[0064] By connecting the solution storage tank 38 at this location, the space for solution recovery can be increased, thus preventing the solution in the desulfurization solution low-level tank 32 from being unable to be discharged when there is too much solution in the desulfurization solution low-level tank 32 and the desulfurization absorption tower 17 does not require solution recovery. This structure can solve the above-mentioned technical problems.

[0065] Example 4

[0066] Reference Figure 5 The technical difference between this embodiment and embodiment 4 is that there are two solution pumps 15 in this embodiment.

[0067] Setting up two solution pumps 15 not only improves the stability of the device's operation, but also allows one of the solution pumps 15 to serve as a backup pump. If one solution pump 15 malfunctions, the other can be used to replace it promptly, preventing the entire device from shutting down due to a single pump malfunction. Alternatively, multiple solution pumps 15 can be configured, achieving 2 in operation and 1 on standby, or 2 in operation and 2 on standby, further enhancing the device's reliability.

[0068] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A natural gas desulfurization apparatus comprising a desulfurization absorption tower (17), a gravity separator (21), a dehydration absorption tower (22), a desulfurization regeneration tower (11), a desulfurization solution low tank (32), characterized by, The gravity separator (21) is connected with a liquid level gauge one (18), the dehydration absorption tower (22) is connected with a liquid level gauge two (23), and the desulfurization solution low-level tank (32) is connected with a liquid level gauge three (31); the desulfurization solution low-level tank (32) is connected with the gravity separator (21) and the dehydration absorption tower (22) through a solution automatic recovery structure; the desulfurization solution low-level tank (32) is connected with the desulfurization regeneration tower (11) and the desulfurization absorption tower (17) through a solution automatic supplement structure; the desulfurization solution low-level tank (32) is connected with a pressure detection structure; the signals of the liquid level gauge one (18), the liquid level gauge two (23), the liquid level gauge three (31), the solution automatic recovery structure, the solution automatic supplement structure, and the pressure detection structure are all connected to a controller; The solution automatic recovery structure comprises a reflux pipe (27) connected between the desulfurization solution low-level tank (32) and the dehydration absorption tower (22) and the gravity separator (21); the reflux pipe (27) connected with the gravity separator (21) is connected with an automatic cut-off valve one (16), and the reflux pipe (27) connected with the dehydration absorption tower (22) is connected with an automatic cut-off valve two (24); the signals of the automatic cut-off valve one (16) and the automatic cut-off valve two (24) are connected to the controller; The reflux pipe (27) connected with the automatic cut-off valve one (16) and the automatic cut-off valve two (24) is connected with two manual valves respectively; the reflux pipe (27) between the automatic cut-off valve one (16) and the manual valve is connected with a flow restrictor one (25); the reflux pipe (27) between the automatic cut-off valve two (24) and the manual valve is also connected with a flow restrictor two (39); The solution automatic supplement structure comprises a solution supplement pipe (33) connected between the desulfurization solution low-level tank (32) and the desulfurization regeneration tower (11) and the desulfurization absorption tower (17); the solution supplement pipe (33) connected with the desulfurization regeneration tower (11) is connected with an automatic cut-off valve three (12) and a one-way valve one (13), and the automatic cut-off valve three (12) and the one-way valve one (13) are connected with a flow restrictor three (40); the solution supplement pipe (33) connected with the desulfurization absorption tower (17) is connected with an automatic cut-off valve four (35) and a one-way valve two (14); the solution supplement pipe (33) connected with the desulfurization solution low-level tank (32) is connected with a start pump (34); the solution supplement pipe (33) connected with the desulfurization absorption tower (17) is connected with at least one solution pump (15); the signals of the automatic cut-off valve three (12), the automatic cut-off valve four (35), the start pump (34), and the solution pump (15) are connected to the controller; The automatic cut-off valve four (35) is connected with the regulating valve (36) between the one-way valve two (14), the regulating valve (36) is connected with the manual valve between the automatic cut-off valve four (35), the regulating valve (36) is also connected with the manual valve between the one-way valve two (14), the regulating valve (36) is connected with the branch pipe at both ends, one end of the branch pipe is connected on the solution supplement pipe (33) between the one-way valve two (14) and the manual valve, the other end is connected on the solution supplement pipe (33) between the automatic cut-off valve four (35) and the other manual valve, the branch pipe is also connected with the manual valve.

2. A natural gas desulphurization unit as claimed in claim 1, wherein, The backflow pipe (27) connected with the gravity separator (21) and the backflow pipe (27) connected with the dehydration absorption tower (22) are both connected with the blowdown main pipe (26), the blowdown main pipe (26) is connected with the manual valve.

3. The natural gas desulfurization device of claim 1, wherein, The solution supplement pipe (33) connected with the desulfurization absorption tower (17) is connected with the branch pipe (37), the branch pipe (37) is connected with the manual valve, the branch pipe (37) is connected with the solution storage tank (38).

4. The natural gas desulfurization device of claim 1, wherein The solution supplement pipe (33) connected with the desulfurization absorption tower (17) is connected with the through pipe for connecting the desulfurization flash tank (19), the through pipe is connected with the control valve.

5. The natural gas desulfurization device of claim 1, wherein The pressure detection structure includes the nitrogen water seal tank (28) and the pressure transmitter (29) for pressure measurement, the pressure transmitter (29) is installed on the pipeline connected between the nitrogen water seal tank (28) and the desulfurization solution low tank (32), the signal of the pressure transmitter (29) is accessed to the controller.

6. A control method for a natural gas desulfurization apparatus according to any one of claims 1 to 5, characterized by, The control method is automatic, quantitative and small flow; The control method for automatically controlling the solution from the gravity separator (21) into the desulfurization solution low tank (32) is that the liquid level value in the gravity separator (21) is detected by the liquid level gauge one (18), when the liquid level is higher than the set high alarm value and the pressure value in the desulfurization solution low tank (32) is lower than the set high alarm value, the automatic cut-off valve one (16) is automatically opened by the controller and an alarm is given, when the liquid level is lower than the set low alarm value or the pressure value is higher than the set high alarm value, the automatic cut-off valve one (16) is automatically closed by the controller; The control method for automatically controlling the solution from the dehydration absorption tower (22) into the desulfurization solution low tank (32) is that the liquid level value in the dehydration absorption tower (22) is detected by the liquid level gauge two (23), when the liquid level is higher than the set high alarm value and the pressure value in the desulfurization solution low tank (32) is lower than the set high alarm value and the liquid level in the gravity separator (21) is lower than the set high alarm value, the automatic cut-off valve two (24) is automatically opened by the controller for desulfurization solution recovery operation, when the liquid level is lower than the set low alarm value or the pressure value is higher than the set high alarm value during the recovery process, the automatic cut-off valve two (24) is automatically closed by the PLC controller. The method for automatically controlling the solution replenishment of the desulfurization regenerator (11) and the desulfurization absorber (17) is as follows: the liquid level value in the desulfurization solution low-position tank (32) is detected by the liquid level gauge three (31), when the liquid level is higher than the high alarm value, the starting pump (34) is automatically opened and the automatic cut-off valve three (12) is opened by the PLC controller, the solution in the desulfurization solution low-position tank (32) is automatically replenished to the desulfurization regenerator (11), during the automatic solution replenishment, when the liquid level in the desulfurization solution low-position tank (32) is higher than the set high alarm value, the automatic cut-off valve four (35) is automatically opened, and the regulating valve (36) is opened at the same time; when the liquid level in the desulfurization solution low-position tank (32) is lower than the set low alarm value, the automatic cut-off valve three (12), the automatic cut-off valve four (35) and the regulating valve (36) are closed at the same time, so as to realize the automatic replenishment of the solution from the desulfurization solution low-position tank (32) to the desulfurization device; The control of the quantitative and small-flow recovery and replenishment of the desulfurization solution is realized through the connected flow-limiting orifice plate one (25), the flow-limiting orifice plate two (39) and the flow-limiting orifice plate three (40).

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