Steam pipe network double system interlocking protection process

Abstract

The present application provides a kind of steam pipe network double system interlock protection process, comprising: the highest pressure grade pipe network of first steam pipe network system and the highest pressure grade pipe network of second steam pipe network system, the lowest pressure grade pipe network of first steam pipe network system and the lowest pressure grade pipe network of second steam pipe network system are communicated into steam whole pipe network by interconnection module;First steam pipe network system is configured with first interlock protection module, second steam pipe network system is configured with second interlock protection module, and steam whole pipe network is configured with third interlock protection module;First interlock protection module, second interlock protection module and third interlock protection module do not interfere with each other during the operation of first steam pipe network system and second steam pipe network system work.The present application realizes double system and single system interlock quick switching by a set of interlock control logic, does not interfere with each other, satisfies the intrinsic safety of steam pipe network and multi-working condition protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipe network interconnection and intercommunication, and particularly relates to a steam pipe network double-system interlocking protection process. BACKGROUND

[0002] Chemical plants usually use steam for production heating and power driving, and the steam is mainly provided by boilers or process devices with rich heat. Generally, multi-stage steam pipe networks are established according to different pressure grades to meet the different pressure and temperature requirements of process devices. According to the scale effect and the advantage of energy comprehensive utilization, chemical plants tend to be larger and more integrated, which is generally characterized by long process flow, complex system, multiple operating conditions and high correlation, which makes the whole plant steam pipe network balance and accident interlocking protection more complex.

[0003] At present, the steam pipe network can only achieve pipe network balance through interlocking protection in an accident state, otherwise it will cause large fluctuations in the pipe network, causing the boilers or key power equipment to shut down, even large-area system shutdown, and the benefits will be severely damaged, which will also bring safety and environmental protection risks and great harm.

[0004] Therefore, it is necessary to study a steam pipe network interlocking protection process to avoid large fluctuations in the steam pipe network. SUMMARY

[0005] The present application provides a steam pipe network double-system interlocking protection process, two single-system steam pipe networks form a steam overall pipe network through an interconnection and intercommunication module, the double-system interlocking protection process is designed according to the steam overall pipe network, and the double-system interlocking protection logic is set according to a third interlocking protection module, which does not interfere with a first interlocking protection module and a second interlocking protection module as single-system interlocking protection.

[0006] The technical solution for achieving the purpose of the present application is as follows:

[0007] A steam pipe network double-system interlocking protection process, comprising:

[0008] The highest pressure grade pipe network of the first steam pipe network system and the highest pressure grade pipe network of the second steam pipe network system, and the lowest pressure grade pipe network of the first steam pipe network system and the lowest pressure grade pipe network of the second steam pipe network system are connected into a steam overall pipe network through an interconnection and intercommunication module;

[0009] The first steam pipe network system is configured with a first interlocking protection module, the second steam pipe network system is configured with a second interlocking protection module, and the steam overall pipe network is configured with a third interlocking protection module;

[0010] The first interlocking protection module, the second interlocking protection module and the third interlocking protection module do not interfere with each other during the operation of the first steam pipe network system and the second steam pipe network system.

[0011] In this invention, two single-system steam pipe networks are interconnected through pipes (interconnection module) to form a dual-system steam pipe network. The dual-system interlocking process is designed according to a single steam pipe network (overall steam pipe network). The dual-system interlocking logic is set according to a set of interlocking control (third interlocking protection module). The dual-system interlocking protection (third interlocking protection module) and the single-system interlocking protection (first interlocking protection module and second interlocking protection module) do not interfere with each other.

[0012] In this invention, the first and second steam pipeline systems have four pressure levels: high-pressure steam pipeline, medium-pressure steam pipeline, low-pressure steam pipeline, and low-low-pressure steam pipeline. This invention connects the high-pressure steam pipelines of the two systems and connects the low-low-pressure steam pipeline systems. The purpose is to combine the high-pressure steam generating and consuming equipment involved in the two systems, analyze the overpressure or underpressure conditions of interlocking processes caused by accidental trips of single, multiple, or combined equipment, and form dual-system interlocking conditions. Connecting the low-low-pressure steam pipelines is to balance the pressure of the two steam pipeline systems.

[0013] In one possible implementation, a third interlocking protection module is used to interlock and protect the highest pressure level pipeline of the first steam pipeline system and the highest pressure level pipeline of the second steam pipeline system.

[0014] The first interlocking protection module is used to interlock and protect the intermediate pressure level pipeline and the lowest pressure level pipeline of the first steam pipeline system.

[0015] The second interlocking protection module is used to interlock and protect the intermediate pressure level pipeline and the lowest pressure level pipeline of the second steam pipeline system.

[0016] In one possible implementation, the highest pressure level pipeline network connects to steam supply equipment and steam production equipment;

[0017] The third interlock protection module protects the steam-using equipment from tripping, causing overpressure in the highest pressure-level pipeline network to reach pressure balance.

[0018] The third interlock protection module protects against pressure imbalance when the steam-generating equipment trips, causing a loss of pressure in the highest pressure-level pipeline.

[0019] In one possible implementation, when the steam equipment trips, the third interlock protection module interlocks and opens the desuperheater and pressure reducer between the highest pressure level pipeline and the second highest pressure level pipeline of the corresponding steam pipeline system.

[0020] When a steam-powered equipment trips, the third interlock protection module interlocks and opens the vent valve between the highest pressure level pipeline and the second highest pressure level pipeline in the corresponding steam pipeline system.

[0021] In one possible implementation, the third interlock protection module determines the valve opening of the desuperheater and pressure reducer based on the steam consumption of the tripped unit, the pipeline capacity, and the high-pressure interlock value of the pipeline.

[0022] In one possible implementation, when a steam-producing unit trips, the third interlocking protection module sets up interlocks according to the number of tripped steam-producing units, and the third interlocking protection module prioritizes interlocking the generator sets in the steam-producing units to be shut down.

[0023] In one possible implementation, the control program of the third interlocking protection module is compiled by converting switch signals into logical conditions;

[0024] The third interlock protection module activates the de-cooling and pressure reducing device by outputting logical commands or receiving signals through the control program.

[0025] In one possible implementation, the first interlocking protection module is the original logic control of the first steam pipeline system;

[0026] The second interlock protection module is the original logic control of the second steam pipeline system;

[0027] The third interlock protection module is a logic control system that adds interlocking logic conditions to the logic control of the first and second interlock protection modules for the highest pressure level pipeline network.

[0028] In one possible implementation, the third interlocking protection module is a logic control formed by adding interlocking logic conditions to the logic control of the first and second interlocking protection modules for the highest pressure level pipeline network, including:

[0029] The logic control formed by the added interlocking logic conditions is mainly for the accident tripping of steam-producing equipment and steam-consuming equipment. The steam-producing equipment includes 6 boilers, and the steam-consuming equipment includes 2 generator sets and 4 air separation units.

[0030] When a steam-producing equipment trips due to an accident, the third interlock protection module for 1 boiler trip, 5 boiler trip, and 6 boiler trips will not trigger the interlock; the third interlock protection module for 2 boiler trips will trigger the interlock to shut down the generator unit; the third interlock protection module for 3 boiler trips and 4 boiler trips will trigger the interlock to shut down the generator unit and the air separation unit.

[0031] When a steam-using equipment trips due to a malfunction, the third interlock protection module of the generator set trips triggers the interlock to open the desuperheater and pressure reducer and the low-pressure steam vent valve; the third interlock protection module of the air separation unit trips triggers the desuperheater and pressure reducer of the first or second steam pipeline system.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] The two single-system steam pipelines (the first steam pipeline system and the second steam pipeline system) of the present invention are interconnected to form an integrated steam pipeline network. The dual-system interlocking protection process is designed according to the integrated steam pipeline network, and the dual-system interlocking protection logic is set according to the third interlocking protection module. The third interlocking protection module as the dual-system interlocking protection, the first interlocking protection module as the single-system interlocking protection, and the second interlocking protection module do not interfere with each other. Attached Figure Description

[0034] Figure 1 A schematic diagram of a dual-system interlock protection process for a steam pipeline network provided by this invention;

[0035] Figure 2 A logic control diagram of an interlocking protection module for dual-system interlocking protection of a steam pipeline network is provided by the present invention.

[0036] In the diagram: 1 - First steam pipeline system; 2 - Second steam pipeline system; 3 - Interconnection module at high-pressure steam pipeline; 4 - Interconnection module at low-pressure steam pipeline; A1 - Generator set #1; A2 - Generator set #2; B1 - Air separation unit #1; B2 - Air separation unit #2; B3 - Air separation unit #3; B4 - Air separation unit #4; C1 - Emergency desuperheating and pressure reducing device for generator sets #1 and #2; C2 - Emergency desuperheating and pressure reducing device for air separation units #1 and #2; C3 - Air separation unit #3 and #4 Emergency desuperheating and pressure reducing device; C4 - Medium-pressure emergency desuperheating and pressure reducing device; C5 - Desuperheating and pressure reducing device 1 between medium and high-pressure pipelines; C6 - Desuperheating and pressure reducing device 1 between medium and low-pressure pipelines; C7 - Desuperheating and pressure reducing device 1 between low-low-low-pressure pipelines; C8 - Desuperheating and pressure reducing device 2 between medium and high-pressure pipelines; C9 - Desuperheating and pressure reducing device 2 between medium and low-pressure pipelines; C10 - Desuperheating and pressure reducing device 2 between low-low-low-pressure pipelines; S1 - High-pressure steam pipeline; S2 - Medium-pressure steam pipeline; S4 - Low-pressure steam pipeline; S5 - Low-low-pressure steam pipeline. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0038] Steam network accidents are mainly caused by boiler and large power equipment shutdowns. In this state, steam network balance is maintained through interlocking protection between the boiler and power equipment, supplemented by process measures or desuperheaters / pressure reducers when necessary. The project was completed and successfully operated in two phases. The high-pressure (S1) and low-pressure (S5) steam networks of the two phases are interconnected, forming a dual-system steam network. The interlocking protection of the dual system is complex, and the switching between dual-system and single-system interlocking is also a new challenge.

[0039] This invention, through research on the interlocking process of a dual-system steam pipeline network, develops an interlocking protection technology for the simultaneous operation of the two systems in a two-phase project's steam pipeline network. A single interlocking control program enables rapid switching between dual-system and single-system interlocking without interference, meeting the inherent safety and multi-condition protection requirements of the steam pipeline network. This solves the drawbacks and risks associated with prolonged self-retrieval and sequential control procedures caused by using multiple interlocking control programs. This interlocking protection technology utilizes the system redundancy of the dual-system interlocking process through delayed interlocking or manual control, aiming to achieve stable, safe, and controllable operation of the process unit.

[0040] This invention provides a dual-system interlocking protection process for steam pipelines, comprising: the highest pressure level pipeline of the first steam pipeline system and the highest pressure level pipeline of the second steam pipeline system, and the lowest pressure level pipeline of the first steam pipeline system and the lowest pressure level pipeline of the second steam pipeline system, connected to form an integrated steam pipeline network via an interconnection module; the first steam pipeline system is equipped with a first interlocking protection module, the second steam pipeline system is equipped with a second interlocking protection module, and the integrated steam pipeline network is equipped with a third interlocking protection module; during the operation of the first and second steam pipeline systems, the first, second, and third interlocking protection modules operate independently without interference.

[0041] In this embodiment of the invention, the first steam pipeline system and the second steam pipeline system are interconnected through pipelines to form a dual steam pipeline system. The dual-system interlocking process is designed according to a single steam pipeline system, and the dual-system interlocking logic is set according to a set of interlocking control programs. The dual-system interlocking protection and the single-system interlocking protection do not interfere with each other.

[0042] In this embodiment of the invention, the interlocking process (overpressure) does not involve setting up an emergency shutdown of the high-pressure steam boiler. Instead, it uses a delayed sequential control procedure to postpone the interlocking or manual shutdown of the boiler, reducing the number of boiler start-ups and shutdowns, improving production responsiveness, and achieving stable operation of the unit. In this embodiment of the invention, the interlocking process (underpressure) selectively shuts down the air separation unit corresponding to the system to which the tripped boiler belongs. By receiving the boiler trip signal and collecting the high-pressure steam (S1) pipeline pressure, the interlocking conditions are set based on the pipeline pressure to postpone the shutdown of the air separation unit, providing an opportunity for planned adjustments to the air separation unit.

[0043] In this embodiment of the invention, two single-system steam pipe networks are interconnected through pipes (interconnection module) to form a dual-system steam pipe network. The dual-system interlocking process is designed according to a single steam pipe network (overall steam pipe network). The dual-system interlocking logic is set according to a set of interlocking control (third interlocking protection module). The dual-system interlocking protection (third interlocking protection module) and the single-system interlocking protection (first interlocking protection module, second interlocking protection module) do not interfere with each other.

[0044] In this invention, the first and second steam pipeline systems have four pressure levels: high-pressure steam pipeline, medium-pressure steam pipeline, low-pressure steam pipeline, and low-low-pressure steam pipeline. This invention connects the high-pressure steam pipelines of the two systems and the low-low-pressure steam pipeline systems of the two systems. The purpose is to combine the high-pressure steam generating and consuming equipment involved in the two systems, analyze the overpressure or underpressure conditions of the interlocking process caused by accidental tripping of single, multiple, and combined equipment, and form dual-system interlocking conditions. Connecting the low-low-pressure steam pipeline is to balance the pressure of the two steam pipeline systems. Preferably, two identical steam pipelines with four pressure levels are used: high-pressure (S1), medium-pressure (S2), low-pressure (S4), and low-low-pressure (S5) steam pipelines. The S1 and S5 steam pipelines are interconnected to form a dual system. The high-pressure (S1) steam pipeline is designed with an interlocking process as a single system, while the other three levels of pipelines are designed with independent interlocking processes. Interlocking processes for overpressure in the high-pressure (S1) steam network caused by boiler equipment tripping and interlocking processes for pressure loss in the high-pressure (S1) steam network when boiler steam generation equipment trips.

[0045] Preferably, a third interlocking protection module is used to interlock and protect the highest pressure level pipeline of the first steam pipeline system and the highest pressure level pipeline of the second steam pipeline system; a first interlocking protection module is used to interlock and protect the intermediate pressure level pipeline and the lowest pressure level pipeline of the first steam pipeline system; and a second interlocking protection module is used to interlock and protect the intermediate pressure level pipeline and the lowest pressure level pipeline of the second steam pipeline system.

[0046] The system prioritizes connecting the highest pressure-level pipeline to steam-using equipment and steam-producing equipment; the third interlock protection module protects against pressure balancing when the tripping of the steam-using equipment causes overpressure in the highest pressure-level pipeline; the third interlock protection module also protects against pressure balancing when the tripping of the steam-producing equipment causes pressure loss in the highest pressure-level pipeline.

[0047] In practical applications, the steam network dual-system interlocking protection process of this invention sets interlocks according to the number of boiler trips, prioritizing the interlocking shutdown of generator units. Simultaneously, considering the self-regulating capability of the process unit, no interlocking shutdown of process units is set. Unlike single-system interlocking, boiler trips do not involve interlocking shutdown of process units; instead, process units are shut down based on low pressure in the high-pressure steam network or manually when multiple boilers trip. The interlocking process converts switch signals into logical conditions to create a control program, which outputs or receives command signals to achieve action control. Based on the original single-system logic control program, a dual-system interlocking logic control program is developed by adding interlocking logic conditions. This dual-system interlocking logic control program includes both the original single-system and newly added single-system interlocking logic control programs. The dual-system interlocking logic control program and the single-system logic control program run on the same processor. Dual-system and single-system interlocking protection are implemented via a host computer (operation interface) mode selection button. The lower-level computer (i.e., the logic control program) implements the interlocking control program by triggering or cutting off interlocking conditions. There are three operating mode selection buttons: dual-system operating mode and two single-system independent operation modes.

[0048] When a steam-using equipment trips, the third interlock protection module interlocks and opens the desuperheater and pressure reducer between the highest pressure level pipeline and the second highest pressure level pipeline of the corresponding steam pipeline system; when a steam-using equipment trips, the third interlock protection module interlocks and opens the vent valve between the highest pressure level pipeline and the second highest pressure level pipeline of the corresponding steam pipeline system.

[0049] The preferred third interlock protection module determines the valve opening of the desuperheater and pressure reducer based on the steam consumption of the tripped unit, the pipeline capacity, and the high and high pressure interlock values ​​of the pipeline.

[0050] When a steam-producing equipment trips, the third interlock protection module sets up interlocks according to the number of tripped steam-producing equipment. The third interlock protection module prioritizes interlocking the generator sets in the steam-producing equipment that are out of service.

[0051] The control program of the preferred third interlock protection module is compiled by converting switch signals into logical conditions; the third interlock protection module realizes the action of the de-cooling and pressure reducing device through the logical output instructions or received signals of the control program.

[0052] The preferred first interlock protection module is the original logic control of the first steam pipeline system; the second interlock protection module is the original logic control of the second steam pipeline system; and the third interlock protection module is a logic control formed by adding interlock logic conditions based on the logic control of the first and second interlock protection modules for the pipeline system with the highest pressure level.

[0053] The preferred third interlock protection module is a logic control system formed by adding interlock logic conditions based on the logic control of the first and second interlock protection modules for the highest pressure level pipeline network. This includes: the logic control formed by the added interlock logic conditions mainly triggers the tripping of steam-producing and steam-consuming equipment in case of an accident. The steam-producing equipment includes 6 boilers, and the steam-consuming equipment includes 2 generator sets and 4 air separation units. When a steam-producing equipment trips due to an accident, the third interlock protection module does not trigger the interlock when 1, 5, or 6 boilers trip; the third interlock protection module triggers the interlock to shut down the generator sets when 2 boilers trip; the third interlock protection module triggers the interlock to shut down the generator sets and air separation units when 3 or 4 boilers trip; when a steam-consuming equipment trips due to a fault, the third interlock protection module triggers the interlock to open the desuperheater and pressure reducer and the low-pressure steam vent valve when the generator set trips; the third interlock protection module triggers the desuperheater and pressure reducer of either the first or second steam pipeline system when the air separation unit trips.

[0054] In practical application, the dual-system interlocking protection process for a steam pipeline network according to an embodiment of the present invention consists of two identical steam pipeline networks with four pressure levels: high pressure (S1), medium pressure (S2), low pressure (S4), and low-low pressure (S5). Interconnection is achieved by linking the S1 and S5 steam pipeline networks of the two systems. The S1 interconnection pipeline capacity is 320 t / h (single boiler capacity), and the S5 interconnection pipeline capacity does not affect the steam pipeline network interlocking protection. The interlocking process involves balanced operating conditions for the steam pipeline network, primarily including the operating status of the boiler and power equipment, as well as the steam pipeline network pressure conditions. This is reflected in the interlocking protection as boiler and power equipment tripping and shutdown, and overpressure or underpressure information for each level of the steam pipeline network.

[0055] According to the system design, the interlocking conditions for single-system operation are designed according to the single-system interlocking process. For dual-system operation, the interlocking conditions for the high-pressure (S1) steam pipeline network are redesigned according to the single-system connection process. The interlocking conditions for other levels are the sum of the single-system interlocking conditions.

[0056] The interlocking process is designed according to a high-pressure (S1) steam pipeline network. It is implemented by combining the high-pressure (S1) steam generating equipment and steam consuming equipment involved in the two systems, analyzing the overpressure or underpressure conditions of the interlocking process caused by accident tripping of single, multiple, or combined equipment, and forming the interlocking conditions of the two systems.

[0057] Preferably, when the high-pressure steam network is overpressurized, interlocking is implemented according to the tripping conditions of 1 or 2 generator units and 1, 2, 3, or 4 air separation units. When 1 generator trips, the interlocking mechanism releases pressure from the desuperheater and pressure reducer. When 2 generators trip, instead of setting a direct interlock to shut down the boiler for a single system, the interlocking mechanism releases pressure from the desuperheater and pressure reducer of the dual-system emergency tank, delaying the interlocking or manually shutting down any one boiler. When 1, 2, 3, or 4 air separation units trip, instead of setting a direct interlock to shut down the boiler for a single system, the interlocking mechanism releases pressure from the desuperheater and pressure reducer of the dual-system emergency tank. Simultaneously, the process unit collects the steam network pressure or the air separation unit trip signal (whichever comes first) and interlocks the process unit to shut down to protect the steam network.

[0058] Preferably, when high-pressure steam loses pressure, interlocks are set for tripping 2, 3, and 4 boilers, while no interlocks are set for tripping 1, 5, and 6 boilers. For a single boiler trip, network balancing is achieved manually through production control; for 5 and 6 boiler trips, orderly shutdown relies on the process unit's own accident interlocks and production control. When 2 boilers trip, one generator unit is interlocked to stop; when 3 boilers trip, 2 generator units are interlocked to stop, and depending on the different combinations of the 3 boiler single-systems, a delayed interlock is selected to stop one air separation unit in each system; when 4 boilers trip, 2 generator units are interlocked to stop, and one air separation unit in each of the two systems is stopped.

[0059] Preferably, high-pressure steam (S1) overpressure occurs when the steam-consuming equipment trips, causing a reduction in high-pressure steam (S1) consumption and resulting in overpressure in the pipeline network. The steam-consuming equipment includes 2 generator sets (in the existing single system, not in the newly added single system) and 4 air separation turbine units (2 in each single system). High-pressure steam (S1) depressurization occurs when the steam-producing equipment trips, causing insufficient high-pressure steam (S1) supply and resulting in depressurization of the pipeline network. The steam-producing equipment consists of 6 high-pressure steam boilers.

[0060] The interlocking logic is as follows: the interlocking process is converted into logical conditions, and the logical conditions are converted into interlocking logic through the development of a control program. The dual-system interlocking logic is set up according to a single logic control program. Based on the original single-system logic control program, a dual-system interlocking logic control program is developed by adding interlocking logic conditions. This program includes the original single-system and the newly added large-system operating condition interlocking logic control programs. The interlocking protection is as follows: in the event of a train trip due to an accident, the interlocking logic receives and sends signals, instructing the steam-using equipment or steam-supplying equipment to shut down urgently or delay shutdown, thereby protecting the pressure balance of each level of the steam network. Protecting the pressure balance of each level of the steam network involves: when high-pressure steam (S1) is overpressured, the pressure is reduced to the medium-pressure (S2) steam network through a desuperheater and pressure reducer; when high-pressure steam (S1) loses pressure, the pressure is increased by shutting down the steam-using equipment. When other levels of steam are overpressured, a desuperheater and pressure reducer combined with a vent valve are used to reduce pressure; when pressure is lost, the steam-using equipment is shut down through an upstream desuperheater and pressure reducer or an interlock.

[0061] The interlocking protection between the dual system and the single system is implemented without interference as follows: For ease of description, we define Operating Condition 1 as the original single system, Operating Condition 2 as the newly built single system, and Operating Condition 3 as the dual system operating condition. 1. Develop interlocking logic programs for Operating Condition 2 and Operating Condition 3 based on the lower-level machine's Operating Condition 1 interlocking logic; 2. Set a mode switching button on the upper-level machine's operating interface and associate this button with the mode selection switch set in the lower-level machine; 3. Use the mode switching button to select whether to activate Operating Condition 3. Based on the selected mode selection switch, trigger the corresponding mode's interlocking conditions and execute related interlocking actions; 4. After the interlock is triggered, execute the relevant actions. After the actions are completed, production personnel can manually adjust according to the actual on-site operating conditions.

[0062] Preferably, step 1 adds interlocking conditions and actions for condition 2 to condition 1. Condition 1 and condition 2 conditions and actions are completely independent. The execution of condition 3 is determined by a mode switching switch and lower-level logic conditions. The mode switching switch in step 2 allows for flexible and rapid commissioning of condition 3, and condition 3 is highlighted after commissioning. In step 3, when condition 3 is not commissioned, condition 1 and condition 2 operate independently. When condition 3 is commissioned, after the interlocking conditions are triggered, some actions of condition 1 and some actions of condition 2 are executed simultaneously. Interlocking conditions that do not need to be executed are masked to disconnect the interlocking logic. In step 4, after the interlock is triggered, the corresponding interlocking actions are executed according to the relevant conditions. After the actions are completed, the process can adjust the relevant actions according to the actual operating conditions.

[0063] like Figure 1 As shown, the steam pipeline network in this embodiment of the invention is characterized by a dual system. "1" and "2" in the figure represent two steam systems, with three operating conditions: independent operation of the two single systems and joint operation of both systems. The interlocking processes need to be studied separately. Since the interlocking logic control program in this embodiment of the invention is set up according to a dual-system configuration, the interlocking process is studied according to the dual-system approach. The results of the dual-system study include the interlocking process for independent operation of the single system. This embodiment of the invention specifically describes the dual-system high-pressure (S1) steam interlocking protection, distinguishing it from single-system interlocking protection.

[0064] To facilitate the description and understanding of interlocking protection technology, the following explains the setup and interlocking process of the dual-system steam pipeline network.

[0065] The project is being constructed in two phases. The steam pipeline pressure levels are the same for both phases. The capacity of the high-pressure steam (S1), medium-pressure steam (S2), and low-pressure steam (S5) pipelines in the phase 1 is 2 times, 0.5 times, and 1.5 times that of the phase 2, respectively, while the capacity of the low-pressure steam (S4) pipeline is basically the same. The construction equipment and process technologies are basically the same in both phases, but the steam pipeline process settings and steam balance methods differ significantly, resulting in substantial differences in the interlocking processes of the steam pipelines in the two phases.

[0066] like Figure 1 As shown, under normal operating conditions, the steam pipeline network at each level can achieve system self-balancing. When the system self-balancing cannot meet the needs of multi-operation production, the steam pipeline network at each level is forcibly adjusted by the process desuperheater and pressure reducer to ensure the stability of the process unit's requirements.

[0067] It should be noted that, Figure 1 The desuperheating and pressure reducing devices C5- between medium and high-pressure pipelines, C6 between medium and low-pressure pipelines, and C7 between low and low-pressure pipelines are all process desuperheating and pressure reducing devices, not emergency desuperheating and pressure reducing devices, meaning they do not participate in the interlocking protection process of this invention. One of the main purposes of process desuperheating and pressure reducing devices is to achieve steam network balance, and the other is to protect the network from overpressure; they can be understood as an auxiliary means to emergency desuperheating and pressure reducing devices.

[0068] In the event of an accident, pressure signals from all levels of the pipeline network trigger protective interlocks, activating the emergency desuperheating and pressure reducing device and the "PV" pressure control vent valve to protect the steam pipeline network pressure, thus ensuring that the process unit can be shut down or its production conditions adjusted according to a preset priority sequence.

[0069] According to the interlocking process analysis, the main accident conditions are the tripping of steam-producing equipment (6 boilers) and steam-consuming equipment (2 generator sets and 4 air separation units). Tripping of other equipment or pipeline overpressure and underpressure interlocking also fall within the scope of the interlocking protection technology of this invention, but since they are no different from single-system interlocking protection technology, this invention will not elaborate on them.

[0070] When a steam-generating equipment trips due to an accident, to prevent a sudden drop in steam pipeline pressure, the interlock logic is triggered according to the following interlock conditions:

[0071] When one boiler trips, the interlock is not triggered.

[0072] When two boilers trip, regardless of which single system the boilers belong to, the interlock will be triggered to stop either generator set A1 or A2.

[0073] When three boilers trip, the system determines which single system the two boilers belong to, triggering an interlock to shut down generator units A1 and A2 and the corresponding single-system air separation unit. For example, when boilers #1, #2, and #3 trip, generator units A1 and A2, as well as one of the air separation units B1 or B2, are interlocked to shut down. Based on the interlocking process and actual operational analysis, this condition can be addressed by choosing not to directly trigger an interlock to shut down a specific air separation unit, but rather by using a low-pressure (S1) steam network interlock to shut down the air separation unit. Alternatively, the interlocking protection time can be calculated based on the network volume to delay the shutdown of the air separation unit. In this embodiment, a low-pressure (S1) steam network interlock is used to shut down one of the air separation units B1, B2, B3, or B4.

[0074] When all four boilers trip, regardless of which single system the boilers belong to, the interlock will be triggered to shut down generator sets A1 and A2, as well as one air separation unit, B1 or B2 air separation unit, or B3 or B4 air separation unit in each single system.

[0075] When boilers 5 and 6 trip, the interlock is not triggered, and the production department will protect the pipeline network according to the emergency control measures.

[0076] When steam-using equipment trips due to an accident, to prevent a sudden increase in steam pipeline pressure, the interlocking logic is triggered according to the interlocking conditions:

[0077] When either generator set A1 or A2 trips, the interlock is triggered to open the emergency desuperheating and pressure reducing device of generator set C1 and the low-pressure (S5) steam vent valve of generator set D1. The former valve is opened to 75%, and the latter to 100%.

[0078] When generator sets A1 and A2 trip simultaneously, the interlock is triggered to open the emergency desuperheating and pressure reducing device of generator set C1 and the low-pressure (S5) steam vent valve of generator set D1. Both valves are 100% open. This condition does not trigger the interlock to shut down the boiler; that is, the interlock logic cuts off the single-system boiler shutdown logic. At this time, the high-pressure (S1) steam network pressure will gradually increase. When it reaches the high interlock value for network pressure, the interlock opens the emergency desuperheating and pressure reducing device of air separation unit C2, with the valve opening at 15%. In this embodiment, a delayed interlock is set to shut down one boiler. The delayed interlock time is determined based on the network volume (in this embodiment, the delay time is 120 seconds).

[0079] When one of the air separation units B1, B2, B3, or B4 trips, the interlock is triggered to open the corresponding single-system C2 or C3 air separation unit's emergency desuperheating and pressure reducing valve, with the valve opening at 60%. Based on the pipeline network operation, the valve opening is manually readjusted, and the boiler is then shut down.

[0080] When two air separation units (B1, B2, B3, and B4) trip, the interlock is triggered to open the corresponding single-system air separation unit's emergency desuperheater and pressure reducer. The valve opening is executed according to the interlock opening of the respective single system. That is, if the air separation units belong to different single systems, the valve opening of the former is 60%, and the valve opening of the latter is 50%; if the air separation units belong to the same single system, the valve opening of both is 100%. For example, when air separation units B1 and B2 trip, the interlock opens the emergency desuperheater and pressure reducer of air separation unit C2, and the opening of C2 is 100%.

[0081] When any three air separation units (B1, B2, B3, and B4) trip, the interlock is triggered to open the corresponding single-system air separation unit's emergency desuperheater and pressure reducer. The valve opening degree is the same as the trip logic for two or one air separation unit. For example, when air separation units B1, B2, and B3 trip, the interlock opens the emergency desuperheater and pressure reducer for air separation units C2 and C3, with C2 opening at 100% and C3 opening at 50%.

[0082] When air separation units B1, B2, B3, and B4 all trip, the interlock is triggered to open the air separation unit desuperheater and pressure reducer, that is, the interlock opens the emergency desuperheater and pressure reducer of air separation units C2 and C3, and the opening degree of C2 and C3 is 100%.

[0083] All of the above-mentioned air separation unit trips triggered the interlock to open the medium-pressure (S2) vent valve, and the opening degree of the vent valve was consistent with the opening degree of C2 and C3.

[0084] The above embodiments describe the interlocking conditions of the high-pressure steam (S1) pipeline network in dual-system operation. According to the technical features of the embodiments of the present invention, the interlocking conditions for other equipment tripping accidents or pipeline overpressure and underpressure are not described, nor is the difference between the interlocking conditions of dual-system and single-system.

[0085] Based on the interlocking condition of high-pressure steam (S1), this embodiment of the invention achieves non-interference between dual-system and single-system interlocking protection through interlocking logic, sequential control program and mode selection.

[0086] like Figure 2 The diagram shows the logic control of the interlocking protection module. Condition 1 refers to the original single system, Condition 2 refers to the newly built single system, and Condition 3 refers to the dual system operation condition.

[0087] The interlocking conditions are selected by the selection module to enable or disable the interlocking conditions or trigger their activation. The interlocking conditions are input into the logic sequence control program through the selection module and converted into interlocking instructions to realize the interlocking action.

[0088] When the interlocking control screen displays operating condition three, the selected module triggers the operating condition three interlocking condition, enters the operating condition three logic sequential control program, and executes the operating condition three interlocking action.

[0089] The three interlocking conditions are the interlocking conditions within the solid-lined box of condition one, the interlocking conditions within the solid-lined box of condition two, and the unique interlocking conditions within the solid-lined box of condition three. The interlocking conditions within the dashed-lined box have had their interlocking logic cut off by shielding and removing them.

[0090] When the interlocking control screen displays operating condition one, select the module to trigger the operating condition one interlocking condition and disable the operating condition two and operating condition three interlocking conditions.

[0091] When the interlocking control screen displays operating condition 2, select the module to trigger the operating condition 2 interlocking condition and disable the operating condition 1 and operating condition 3 interlocking conditions.

[0092] The features and beneficial effects of the embodiments of the present invention are reflected in:

[0093] 1. In the embodiment of the present invention, the interlocking process (overpressure) does not set up an interlocking emergency shutdown of the high-pressure steam boiler. Instead, it adopts a delayed sequential control program to delay the interlocking or manually shut down the boiler, thereby reducing the number of boiler start-ups and shutdowns, improving production responsiveness, and achieving stable operation of the equipment.

[0094] 2. In the embodiment of the present invention, the interlocking process (pressure loss) selectively shuts down the air separation unit corresponding to the system to which the tripped boiler belongs. By receiving the boiler trip signal and collecting the high-pressure steam (S1) pipeline pressure, the interlocking conditions are set to delay the shutdown of the air separation unit based on the pipeline pressure, thus giving the air separation unit an opportunity for planned adjustments.

[0095] 3. In this embodiment of the invention, operating conditions 1 and 2 are set independently on the lower-level computer. Operating condition 3, except for the addition of interlocking conditions and actions, has its other logic nested within operating conditions 1 and 2 via a mode selection switch. This aims to reduce the scanning time and calculations required for the control system program, effectively improving the safety and speed of the lower-level program execution. Furthermore, after the interlocking action is completed, process personnel can manually control the system, ensuring both device safety and operational flexibility.

[0096] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

[0097] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0098] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A dual-system interlocking protection process for steam pipeline networks, characterized in that, include: The highest pressure level pipeline of the first steam pipeline system and the highest pressure level pipeline of the second steam pipeline system, as well as the lowest pressure level pipeline of the first steam pipeline system and the lowest pressure level pipeline of the second steam pipeline system, are connected to form an integrated steam pipeline network through interconnection modules. The first steam pipeline system is equipped with a first interlock protection module, the second steam pipeline system is equipped with a second interlock protection module, and the overall steam pipeline system is equipped with a third interlock protection module. The highest pressure level pipeline network connects to steam and steam production equipment; The third interlock protection module protects the steam-using equipment from tripping, causing overpressure in the highest pressure-level pipeline network to reach pressure balance. The third interlock protection module protects against pressure imbalance when the steam-generating equipment trips, causing a loss of pressure in the highest-pressure-level pipeline network. During the operation of the first and second steam pipeline systems, the first interlock protection module, the second interlock protection module, and the third interlock protection module do not interfere with each other. Interlocking conditions are enabled or disabled or triggered via a selection module. Interlocking conditions are input into the logic sequence control program via the selection module, where they are converted into interlocking commands to implement interlocking actions. When the interlocking control screen displays Condition 3, the selection module triggers the Condition 3 interlocking conditions, enters the Condition 3 logic sequence control program, and executes the Condition 3 interlocking action. When the interlocking control screen displays Condition 1, the selection module triggers the Condition 1 interlocking conditions, disabling or disabling Condition 2 and Condition 3 interlocking conditions. When the interlocking control screen displays Condition 2, the selection module triggers the Condition 2 interlocking conditions, disabling or disabling Condition 1 and Condition 3 interlocking conditions. Condition 1 refers to the original single system, Condition 2 refers to a newly built single system, and Condition 3 refers to a dual-system operating condition.

2. The steam pipeline dual-system interlocking protection process according to claim 1, characterized in that, A third interlocking protection module is used to interlock and protect the highest pressure level pipeline of the first steam pipeline system and the highest pressure level pipeline of the second steam pipeline system. The first interlocking protection module is used to interlock and protect the intermediate pressure level pipeline and the lowest pressure level pipeline of the first steam pipeline system. The second interlocking protection module is used to interlock and protect the intermediate pressure level pipeline and the lowest pressure level pipeline of the second steam pipeline system.

3. The steam pipeline dual-system interlocking protection process according to claim 2, characterized in that, When steam-using equipment trips, the third interlock protection module interlocks and opens the desuperheater and pressure reducer between the highest pressure level pipeline and the second highest pressure level pipeline of the corresponding steam pipeline system. When a steam-powered equipment trips, the third interlock protection module interlocks and opens the vent valve between the highest pressure level pipeline and the second highest pressure level pipeline in the corresponding steam pipeline system.

4. The steam pipeline dual-system interlocking protection process according to claim 1, characterized in that, The third interlock protection module determines the valve opening of the desuperheater and pressure reducer based on the steam consumption of the tripped unit, the pipeline capacity, and the high-pressure interlock values ​​of the pipeline.

5. The steam pipeline dual-system interlocking protection process according to claim 2, characterized in that, When a steam-producing unit trips, the third interlock protection module sets up interlocks according to the number of tripped steam-producing units. The third interlock protection module prioritizes interlocking the generator sets in the steam-producing units that are in use.

6. The steam pipeline dual-system interlocking protection process according to claim 5, characterized in that, The control program for the third interlocking protection module is compiled by converting switch signals into logical conditions; The third interlock protection module activates the de-cooling and pressure reducing device by outputting logical commands or receiving signals through the control program.

7. The steam pipeline dual-system interlocking protection process according to claim 1, characterized in that, The first interlocking protection module is the original logic control of the first steam pipeline system; The second interlock protection module is the original logic control of the second steam pipeline system; The third interlock protection module is a logic control system that adds interlocking logic conditions to the logic control of the first and second interlock protection modules for the highest pressure level pipeline network.

8. The steam pipeline dual-system interlock protection process according to claim 7, characterized in that, The third interlocking protection module is a logic control system that adds interlocking logic conditions to the logic control of the first and second interlocking protection modules for the highest pressure level pipeline network, including: The logic control formed by the added interlocking logic conditions is mainly for the accident tripping of steam-producing equipment and steam-consuming equipment. The steam-producing equipment includes 6 boilers, and the steam-consuming equipment includes 2 generator sets and 4 air separation units. When a steam-producing equipment trips due to an accident, the third interlock protection module for 1 boiler trip, 5 boiler trip, and 6 boiler trips will not trigger the interlock; the third interlock protection module for 2 boiler trips will trigger the interlock to shut down the generator unit; the third interlock protection module for 3 boiler trips and 4 boiler trips will trigger the interlock to shut down the generator unit and the air separation unit. When a steam-using equipment trips due to a malfunction, the third interlock protection module of the generator set trips triggers the interlock to open the desuperheater and pressure reducer and the low-pressure steam vent valve; the third interlock protection module of the air separation unit trips triggers the desuperheater and pressure reducer of the first or second steam pipeline system.

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