A three-converter gasholder joint operation system and method

Abstract

The present invention relates to the technical field of converter gas recovery, storage, and utilization in the metallurgical industry. It proposes a system and method for the combined operation of three converter gasholders. This system comprises a basic process control system consisting of a two-stage piston converter gas main tank, a two-stage piston converter gas auxiliary tank, and a single-stage piston converter gasholder. The single-stage piston converter gasholder is integrated with the two-stage piston converter gas main tank and the two-stage piston converter gas auxiliary tank, which operate in series. The gas storage pressure of the single-stage piston converter gasholder is set between the first-stage piston pressure of the auxiliary tank and the second-stage piston pressure of the main tank. This invention effectively simplifies the pressure levels for the combined operation of the three gasholders, facilitates the independent operation and control of two converter gasholders, or even a single converter gasholder, and facilitates the configuration of safety instrumentation systems for the converter gasholders.

Description

Technical Field

[0001] The present invention belongs to the technical field of converter gas recovery, storage and utilization in the metallurgical industry, and particularly relates to a three-converter gasholder joint operation system and method. Background Art

[0002] Converter gasholders are essential power equipment for converter gas recovery and utilization in steel mills. Traditionally, rubber membrane-sealed dry gasholders (commonly known as PRC (piston, rubber membrane seal, cylindrical shell) dry gasholders, Wiggins tanks, or membrane tanks) have been used. Membrane-sealed gasholders utilize side panels at the bottom of the tank to seal the gas, while a rubber membrane secured between the side panels and the piston at the top seals the gas. The pistons are categorized as either single-stage or two-stage pistons, depending on the number of sections in the sealing membrane. Single-stage piston gasholders (hereinafter referred to as single-stage) maintain a constant gas storage pressure, while two-stage piston gasholders (hereinafter referred to as two-stage) conserve steel but have two different gas pressure levels. Membrane-sealed dry gasholders are widely used for converter gas storage due to their advantages, such as fast piston speed and suitability for storing gas with high dust content. However, due to limitations in the length of the rubber mold, these gasholders are difficult to expand in capacity. Consequently, insufficient capacity necessitates the need to increase the number of gasholders.

[0003] Converter gas is extracted from the converter by an exhaust fan. The exhaust fan typically boosts the pressure by approximately 5 kPa, and qualified gas reaches the gasholder inlet at a pressure of approximately 3 kPa. After being mixed within the converter gasholder, it is pressurized and delivered to users. Currently, there are successful experiences in operating two or fewer converter gasholders together, particularly with two two-stage gasholders operating in series (the main gasholder supplies and discharges gas, and the auxiliary gasholder is supplied via the main gasholder). This has yielded satisfactory results. However, there is no precedent in China or abroad for adding a second converter gasholder to the existing two-converter in-line operation to meet production needs. Furthermore, the existing three-converter gasholder combined operation model uses a method that adjusts the opening of the gasholder inlet valve to control the height of the piston. This method suffers from frequent inlet valve adjustments, severe wear, and frequent maintenance. Any maintenance can render all converter gas unrecoverable. (See "Optimal Control of Converter Gasholder Clusters in Steel Enterprises" for more information.) Furthermore, large and medium-sized converter gasholders are generally significant sources of hazardous chemicals. With rising safety standards, the deployment of safety instrumentation systems also needs to be considered. Therefore, it is necessary to design a three-converter gasholder joint operation system based on the in-line operation of two two-stage gasholders. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a system and method for the joint operation of three converter gas holders, aiming to solve the pressure level and configuration problems of the safety instrument system for the gas holders in the joint operation of the three gas holders.

[0005] The present invention is achieved through the following technical solutions:

[0006] The present invention provides a three-converter gas tank joint operation system, including a basic process control system, which is composed of a two-stage piston converter gas main tank, a two-stage piston converter gas auxiliary tank and a one-stage piston converter gas tank. The one-stage piston converter gas tank is combined on the basis of the two-stage piston converter gas main tank and the two-stage piston converter gas auxiliary tank running in series, and the gas storage pressure of the one-stage piston converter gas tank is set between the first-stage piston pressure of the two-stage piston converter gas auxiliary tank and the second-stage piston pressure of the two-stage piston converter gas main tank.

[0007] The principle of the present invention is: a one-stage piston converter gas tank with a constant gas storage pressure is used to operate in parallel with a two-stage piston converter gas main tank and a two-stage piston converter gas auxiliary tank that are operated in series, that is, the gas inlet pipe and the gas outlet pipe of the one-stage piston converter gas tank are connected to the supporting pipelines (converter gas main pipe, reflux / synthesis gas pipe, etc.) of the existing two-stage piston converter gas main tank and the two-stage piston converter gas auxiliary tank that are operated in series, and the gas storage pressure P5 of the one-stage piston converter gas tank is set, and the gas pressure of the two-stage piston converter gas main tank is set. The piston pressure is P1-P3. The piston pressure of the two-stage piston converter gas auxiliary tank is P2-P4, with P4>P3>P2>P1, and P5 is operated between P2 and P3. When the three tanks are operated in conjunction, the gas outlet pipe and gas return pipe of the two-stage piston converter gas auxiliary tank are also cut off by the water seals of the corresponding cut-off devices (consistent with the in-line operation of the two tanks). The gas return pipe of the one-stage piston converter gas tank is also cut off by the water seals of the corresponding cut-off devices. Its reflux function is mainly realized by the gas return pipe of the two-stage piston converter gas main tank. At the same time, the piston height or tank capacity of the three converter gas tanks is set to H4>H3>H2>H1>0.5H (approximately half the tank capacity)>L1>L2>L3>L4>L5>L6>0. The newly added one-stage piston converter gas tank also has a separate basic production process control system. The interlocking control logic of its tank positions and valves is as follows:

[0008] 1. Interlocking conditions of the control valve (C1 valve) on the gas inlet pipe

[0009] 1) C1 valve opening conditions (initial state: C1 valve is closed);

[0010] 1.1) The opening condition of C1 valve is: when the cabinet level of the one-stage piston converter gas tank is lower than 0.5H and the cabinet level of the two-stage piston converter gas main tank is greater than 0.5H, C1 valve opens;

[0011] 1.2) C1 valve closing condition (initial state: C1 valve is open);

[0012] 1.2.1) High cabinet interlock: When the cabinet level of the one-stage piston converter gas cabinet is higher than H1, an alarm will be triggered, and when it is higher than H2, the C1 valve will be automatically shut down;

[0013] 1.2.2) Low cabinet interlock: When the cabinet level of the one-stage piston converter gas cabinet is lower than L4, the C1 valve will be automatically closed (the only possible abnormality is that the cabinet levels of the two-stage piston converter gas main cabinet and the two-stage piston converter gas sub-cabinet are both at low levels, and the one-stage piston converter gas cabinet flows out to the two-stage piston converter gas main cabinet and the two-stage piston converter gas sub-cabinet through the gas inlet pipe; when the cabinet level of the two-stage piston converter gas main cabinet rises to above 0.5H, the C1 valve will open).

[0014] 2. Interlocking conditions of the control valve (C2 valve) on the gas outlet pipe

[0015] 1) When the level of the gas tank of the one-stage piston converter is lower than L3, the C2 valve will be automatically closed and reopened when the level rises to L2.

[0016] 2) When the level of the one-stage piston converter gas tank is higher than H3, the C2 valve will be automatically closed (abnormal, it is very likely that the level of the two-stage piston converter gas main tank and the two-stage piston converter gas auxiliary tank is at a high level, and gas flows into the one-stage piston converter gas tank through the gas outlet pipe); the condition for the C2 valve to be reopened is: the level of the two-stage piston converter gas main tank or the two-stage piston converter gas auxiliary tank is less than L1.

[0017] The advantages of the present invention are as follows: while continuing to use the existing two two-stage converter gas holders for serial operation, the present invention minimizes the impact on the normal production of the existing two gas holders for serial operation, simplifies the pressure level of the joint operation of the three gas holders, facilitates the independent operation and control of the two gas holders or even a single gas holder, and facilitates the configuration of a safety instrument system for the gas holders.

[0018] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings, in which:

[0020] Figure 1 This is a schematic diagram of the three converter gas holder joint operation system of the present invention.

[0021] Figure numerals: 1 is the converter gas main, 2 is the shut-off device VII, 3 is the control valve V (or C1), 4 is the one-stage piston converter gas cabinet, 5 is the shut-off device IV, 6 is the control valve III (or B1), 7 is the two-stage piston converter gas sub-cabinet, 8 is the shut-off device I, 9 is the control valve I (or A1), 10 is the two-stage piston converter gas main cabinet, 11 is the shut-off device III, 12 is the control valve II (or A2), 13 is the shut-off device II, 14 is the reflux / synthesis gas pipe, 15 is the gas compressor I, 16 is the control valve IV (or B2), 17 is the shut-off device V, 18 is the shut-off device VI, 19 is the control valve VI (or C2), 20 is the shut-off device VIII, 21 is the shut-off device IX, and 22 is the gas compressor II. DETAILED DESCRIPTION

[0022] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0023] like Figure 1As shown, the three-converter gas tank joint operation system mentioned in this embodiment includes a basic process control system consisting of a two-stage piston converter gas main tank 10, a two-stage piston converter gas auxiliary tank 7, and a one-stage piston converter gas tank 4. The two-stage piston converter gas main tank 10 and the two-stage piston converter gas auxiliary tank 7, which operate in series, are combined with a one-stage piston converter gas tank 4 to form a three-tank joint mode. The gas storage pressure of the one-stage piston converter gas tank 4 is set between the first piston pressure of the two-stage piston converter gas auxiliary tank 7 and the second piston pressure of the two-stage piston converter gas main tank 10. In this way, the one-stage piston converter gas tank 4, which has a constant gas storage pressure, is operated in parallel with the two existing two-stage gas tanks operating in series, and the corresponding gas storage pressure is set within this range. At the same time, the gas inlet pipe, gas outlet pipe, and gas return pipe of the one-stage piston converter gas tank 4 are all connected to the supporting pipelines of the two existing two-stage gas tanks running in series. That is, the gas inlet pipe of the two-stage piston converter gas main tank 10, the gas inlet pipe of the two-stage piston converter gas sub-tank 7, and the gas inlet pipe of the one-stage piston converter gas tank 4 are all connected to the converter gas main pipe 1 from the primary dust removal of the steel plant, and each is equipped with a shut-off device I8, a shut-off device IV5, a shut-off device VII2, and a control valve. Ⅰ9, control valve Ⅲ6, control valve Ⅴ3; the gas outlet pipe of the two-stage piston converter gas main cabinet 10, the gas outlet pipe of the two-stage piston converter gas auxiliary cabinet 7, and the gas outlet pipe of the one-stage piston converter gas cabinet 4 are all connected to the original gas compressor Ⅰ15, and each is equipped with another shut-off device Ⅱ13, shut-off device Ⅴ17, shut-off device Ⅷ20 and another control valve Ⅱ12, control valve Ⅳ16, control valve Ⅵ19; the gas return pipe of the two-stage piston converter gas main cabinet 10, the two-stage movable The gas return pipe of the plug converter gas sub-tank 7 and the gas return pipe of the one-stage piston converter gas tank 4 are both connected to the reflux / synthesis gas pipe 14, and are each provided with another shut-off device III 11, a shut-off device VI 18, and a shut-off device IX 21. All the shut-off devices adopt a structure combining a gas water seal and a blind plate, and all the control valves can adopt pneumatic butterfly valves with remote control. Due to the large fluctuation of the gas tank inlet flow, the gas inlet pipe is equipped with a remote fast control valve. Two two-stage gas tanks are in series. During operation, the shut-off device II13 of the gas outlet pipe (without the original gas compressor I15) of the two-stage piston converter gas main cabinet 10 is normally open, and the gas is sent to the original gas compressor I15 and then to the user. The shut-off device III11 on the gas return pipe connected to the return / synthetic gas pipe 14 is normally open; the shut-off device V17 on the gas outlet pipe and the shut-off device VI18 on the gas return pipe of the two-stage piston converter gas sub-cabinet 7 are normally closed, and the gas inlet and outlet of the two-stage piston converter gas sub-cabinet 7 are all completed through its inlet pipe.Shutoff device IX 21 on the gas return pipe of the single-stage piston converter gas tank is normally closed because the return / synthesis gas pipe 14 always flows into the lower-pressure two-stage piston converter gas main tank 10. The purpose of the control valve is to automatically close the control valve when the gas levels of the single-stage piston converter gas tank 4, the two-stage piston converter gas main tank 10, and the two-stage piston converter gas auxiliary tank 7 reach the high level or fall below the low level alarm, thereby protecting the converter gas tank.

[0024] This operating system also includes a safety instrument system (SIS), that is, an emergency stop safety interlock system. This system is independent of the basic process control system and is in a dormant or static state when production is normal. Once a situation occurs in the production equipment or facilities that may cause a safety accident, it can act instantly and accurately to safely stop the production process or automatically enter a predetermined safe state. It has high reliability (that is, functional safety).

[0025] Because the gas inlet and outlet pipes of the three gasholders use a water-seal shutoff mode, which typically takes half an hour, each gasholder's gas inlet and outlet pipes are equipped with remotely controlled control valves to align with the safety instrumentation system. Rapid shutoff of these pipes can be achieved by first shutting off the valves, while a longer shutoff followed by a water-seal shutoff is required. In other words, each gasholder, acting as a major hazardous chemical source, possesses a safety instrumentation system that can, in the event of a failure of the basic process control system, shut off the corresponding gas inlet or outlet control valves, bringing the gasholder into a predetermined safe state.

[0026] In this embodiment, the gas outlet pipe is also connected to a newly added gas compressor II 22, which is arranged in parallel with the existing gas compressor I 15 and is independently controlled relative to the existing gas compressor I 15. To reduce interference between the operations of the different gas compressors and minimize the impact on the existing basic production process control system, the basic process control systems of the newly added gas compressor II 22 and the existing gas compressor I 15 are operated in a relatively independent parallel mode. That is, the single-stage piston converter gas tank 4 and the newly added gas compressor II 22 share a single basic process control system.

[0027] The joint operation method based on the three-stage converter gas tank joint operation system includes: controlling the gas storage pressure of the one-stage piston converter gas tank 4 in the basic process control system to operate between the first-stage piston pressure of the two-stage piston converter gas auxiliary tank 7 and the second-stage piston pressure of the two-stage piston converter gas main tank 10; and in the event of failure of the basic process control system, and when the tank level of the one-stage piston converter gas tank 4 reaches its upper limit or lower limit, the safety instrument system can control the gas inlet pipe and gas outlet pipe of the one-stage piston converter gas tank 4 to be lowered. The control valve V3 and control valve VI19 are closed, and when the cabinet position of the two-stage piston converter gas main cabinet 10 reaches its high limit or low limit, the safety instrument system can control the respective control valves I9 and II12 on the gas inlet pipe or gas outlet pipe of the two-stage piston converter gas main cabinet 10 to be closed, and when the cabinet position of the two-stage piston converter gas sub-cabinet 7 reaches its high limit or low limit, the safety instrument system can control the respective control valves III 6 and control valve IV16 on the gas inlet pipe or gas outlet pipe of the two-stage piston converter gas sub-cabinet 7 to be closed, so as to bring the corresponding converter gas cabinet into a predetermined safe state.

[0028] Specifically, referring to the numerical table below, taking a certain steel plant as an example, the two converter gas holders commissioned earlier were designed for in-line operation. Specifically, the gas inlet control valves I9 and III6 of the two-stage piston converter gas main tank 10 (hereinafter referred to as the main tank) and the two-stage piston converter gas auxiliary tank 7 (hereinafter referred to as the auxiliary tank) were normally open, and the gas outlet and return pipes of the main tank were normally open. The water seals of the auxiliary tank's gas outlet and return pipes were normally closed, and gas inlet and outlet of the auxiliary tanks were all controlled through the main tank. When operating in a single tank, the gas inlet, outlet, and return pipes of each tank were all open. The design operating pressure of the main tank was P1 to P3 kPa, and that of the auxiliary tank was P2 to P4 kPa. The pressure change point height for both the main and auxiliary tanks was L1. The gas storage pressure P5 of the newly added one-stage piston converter gas holder 4 (hereinafter referred to as the new tank) was between P2 and P3. At the same time, the piston height or cabinet capacity of the three converter gas tanks is set to H4>H3>H2>H1>0.5H (about half of the cabinet capacity)>L1>L2>L3>L4>L5>L6>0.

[0029] Marker number table

[0030]

[0031] To minimize the impact of the new cabinet on the existing two-cabinet in-line production system and improve control over the gas cabinet, a major hazard source, the basic process control system of the new cabinet is relatively independent. That is, a separate basic process control system is set up, and the interlocking control logic of the new cabinet position and the basic process control system of each valve is as follows:

[0032] 1. Interlocking conditions of control valve V3 (C1 valve) on the gas inlet pipe

[0033] 1) C1 valve opening conditions (initial state: C1 valve is closed);

[0034] 1.1) The opening condition of C1 valve is: when the cabinet position of the new cabinet is less than 0.5H and the cabinet position of the main cabinet is greater than 0.5H, C1 valve opens;

[0035] 1.2) C1 valve closing condition (initial state: C1 valve is open);

[0036] 1.2.1) High cabinet interlock: When the cabinet level of the new cabinet is higher than H1, an alarm will be triggered, and when it is higher than H2, the C1 valve will be automatically shut down;

[0037] 1.2.2) Low cabinet interlock: When the cabinet position of the new cabinet is lower than L4, the C1 valve will be automatically closed (the only possible abnormality is that the cabinet positions of the main cabinet and the auxiliary cabinet are both at low positions, and the new cabinet flows out to the main cabinet and the auxiliary cabinet through its gas inlet pipe; when the cabinet position of the main cabinet rises to above 0.5H, the C1 valve will open).

[0038] 2. Interlocking conditions of control valve VI19 (C2 valve) on its gas outlet pipe

[0039] 1) When the position of the new cabinet is lower than L3, the C2 valve will be automatically closed and reopened when the cabinet position rises to L2.

[0040] 2) When the position of the new cabinet is higher than H3, the C2 valve will be automatically closed (abnormal, it is very likely that the cabinet positions of the main cabinet and the auxiliary cabinet are at a high position, and the gas flows into the new cabinet through the gas outlet pipe); the condition for the C2 valve to be reopened is: the cabinet position of the main cabinet or the auxiliary cabinet is less than L1.

[0041] 3. The main cabinet position is interlocked with control valve Ⅰ9 (A1 valve) and control valve Ⅱ12 (A2 valve)

[0042] 1) High-level alarm and interlocking of the cabinet

[0043] 1.1) When the cabinet reaches H2, an upper limit alarm is issued;

[0044] 1.2) When the cabinet reaches H3, the upper limit high alarm is issued and the A1 valve on the gas inlet pipe is closed;

[0045] 1.3) When the cabinet level drops to H2, the upper limit alarm is released and the A1 valve is opened;

[0046] 2) Its cabinet low position alarm and interlock

[0047] 2.1) The cabinet level drops to L3 and is filled into the main cabinet through the reflux / synthetic gas pipe 14, with the filling amount being 50% of the maximum synthetic converter gas volume;

[0048] 2.2) The piston drops to L4, a low alarm is issued, and the amount of synthesis converter gas charged is increased to full amount;

[0049] 2.3) The piston drops to L6, a low-low alarm is issued, and the A2 valve on the gas outlet pipe and the original gas compressor I15 are closed;

[0050] 2.4) When the piston stroke rises to L3, the interlock and alarm are released and the A2 valve is opened.

[0051] 4. The cabinet position of the auxiliary cabinet is interlocked with the control valve Ⅲ6 (B1 valve) and the control valve Ⅳ16 (B2 valve)

[0052] 1) When the pressure in the main cabinet rises to between P1 and P3, open the B1 valve on the gas inlet pipe of the auxiliary cabinet;

[0053] 2) When the auxiliary cabinet position drops to L4, close the B2 valve on the gas outlet pipe.

[0054] During maintenance on the auxiliary cabinet, shutoff device IV5 and control valve III6 on its gas inlet pipe, shutoff device V17 and control valve IV16 on its gas outlet pipe, and shutoff device VI18 on its gas return pipe are all closed. The main cabinet and the new cabinet operate in conjunction with each other. The main cabinet's shutoff device I8 and control valve I9 ​​on its gas inlet pipe, shutoff device II13 and control valve II12 on its gas outlet pipe, and shutoff device III11 on its gas return pipe are all fully open. The new cabinet's shutoff devices VII2, VIII20, control valve V3, and control valve VI19 on its gas inlet and outlet pipes are fully open, and shutoff device IX21 on its gas return pipe is closed. The same principles apply to the combined operation of the auxiliary cabinet and the new cabinet, and will not be further explained.

[0055] The safety instrument system is relatively independent from the basic process control system and is shared by three gasholders. For each gasholder, it at least includes the closure of the control valve on the gas inlet pipe when the cabinet capacity reaches H4 and the closure of the control valve on the gas outlet pipe when the cabinet capacity reaches L4, ensuring that the gasholder, a major hazard source of dangerous chemicals, remains in a safe state after a failure of the basic process control system of the gasholder.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. For example, the water seal may be replaced by other shut-off devices; the control valve may be a valve in the shut-off device that opens and closes faster; the cabinet height may be represented by the piston height or the corresponding cabinet capacity, etc. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is intended to encompass such modifications and variations.

Claims

1. A three-converter gas holder joint operation system, characterized in that: The invention comprises a basic process control system, which is composed of a two-stage piston converter gas main cabinet (10), a two-stage piston converter gas auxiliary cabinet (7) and a one-stage piston converter gas cabinet (4), wherein the one-stage piston converter gas cabinet is combined with the two-stage piston converter gas main cabinet and the two-stage piston converter gas auxiliary cabinet which are operated in series, and the gas storage pressure of the one-stage piston converter gas cabinet is set between the first-stage piston pressure of the two-stage piston converter gas auxiliary cabinet and the second-stage piston pressure of the two-stage piston converter gas main cabinet; The gas inlet pipes of the two-stage piston converter gas main cabinet, the two-stage piston converter gas auxiliary cabinet and the one-stage piston converter gas cabinet are all connected to the converter gas main pipe (1); the gas outlet pipes of the two-stage piston converter gas main cabinet, the two-stage piston converter gas auxiliary cabinet and the one-stage piston converter gas cabinet are all arranged in parallel and connected to two relatively independent gas compressors I (15) and gas compressor II (22); the gas return pipes of the two-stage piston converter gas main cabinet, the two-stage piston converter gas auxiliary cabinet and the one-stage piston converter gas cabinet are all connected to the return / synthetic gas pipe (14); It also includes a safety instrument system that is independent of the basic process control system, and the safety instrument system will urgently cut off the corresponding valves to enter a safe state when the basic process control system fails. Remote control valves are configured on the gas inlet pipe and the gas outlet pipe. Quick cutting is done by the remote control valve, and long-term cutting is done by water seal cutting.

2. The three-converter gas holder joint operation system according to claim 1 is characterized in that: The gas inlet pipe, gas outlet pipe and gas return pipe of the two-stage piston converter gas main cabinet are respectively provided with a cutting device I (8), a cutting device II (13) and a cutting device III (11); the gas inlet pipe, gas outlet pipe and gas return pipe of the two-stage piston converter gas auxiliary cabinet are respectively provided with a cutting device IV (5), a cutting device V (17) and a cutting device VI (18); the gas inlet pipe, gas outlet pipe and gas return pipe of the one-stage piston converter gas cabinet are respectively provided with a cutting device VII (2), a cutting device VIII (20) and a cutting device IX (21).

3. The three-converter gas holder joint operation system according to claim 2 is characterized in that: A control valve I (9) and a control valve II (12) are provided on the gas inlet pipe and the gas outlet pipe of the two-stage piston converter gas main cabinet and are respectively opposite to the cut-off devices I (8) and the cut-off devices II (13) on the two-stage piston converter gas main cabinet; a control valve III (6) and a control valve IV (16) are provided on the gas inlet pipe and the gas outlet pipe of the two-stage piston converter gas auxiliary cabinet and are respectively opposite to the cut-off devices IV (5) and the cut-off devices V (17) on the two-stage piston converter gas auxiliary cabinet; a control valve V (3) and a control valve VI (19) are provided on the gas inlet pipe and the gas outlet pipe of the one-stage piston converter gas cabinet and are respectively opposite to the cut-off devices VII (2) and the cut-off devices VIII (20) on the one-stage piston converter gas cabinet.

4. A method for joint operation of three converter gas holders, characterized in that: Based on the three-stage converter gas tank joint operation system as described in any one of claims 1 to 3, the joint operation method is to control the gas storage pressure of the one-stage piston converter gas tank (4) in the basic process control system to operate between the one-stage piston pressure of the two-stage piston converter gas auxiliary tank (7) and the two-stage piston pressure of the two-stage piston converter gas main tank (10).

5. The method for joint operation of three converter gas holders according to claim 4, characterized in that: When the cabinet position of the one-stage piston converter gas tank reaches its upper limit or lower limit, the basic process control system controls the control valve V and the control valve VI on its gas inlet pipe and gas outlet pipe to be closed.

6. The method for joint operation of three converter gas holders according to claim 4, characterized in that: In the event of failure of the basic process control system and when the cabinet position of the one-stage piston converter gas tank reaches its upper limit or lower limit, the safety instrument system will urgently cut off the control valve V and control valve VI on its gas inlet pipe and gas outlet pipe to bring it into a predetermined safe state.

7. The method for joint operation of three converter gas holders according to claim 4, characterized in that: In the event of failure of the basic process control system and when the cabinet level of the two-stage piston converter gas main cabinet reaches its upper limit, the safety instrument system will urgently cut off the control valve I on its corresponding gas inlet pipe, or when the cabinet level of the two-stage piston converter gas main cabinet reaches its lower limit, the safety instrument system will urgently cut off the control valve II on its corresponding gas outlet pipe, so as to bring it into a predetermined safe state.

8. The method for joint operation of three converter gas holders according to claim 4, characterized in that: In the event of failure of the basic process control system and when the cabinet level of the two-stage piston converter gas auxiliary cabinet reaches its upper limit, the safety instrument system will urgently cut off the control valve III on its corresponding gas inlet pipe, or when the cabinet level of the two-stage piston converter gas auxiliary cabinet reaches its lower limit, the safety instrument system will urgently cut off the control valve IV on its corresponding gas outlet pipe, so as to bring it into a predetermined safe state.

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