Integrated control system and method for safe storage and use of liquid ammonia

Abstract

This application provides an integrated control system and method for the safe storage and use of liquid ammonia. The system, by setting up an emergency unit for liquid ammonia storage, automatically lowers the liquid ammonia cylinder into a water tank using a lifting support frame upon detection of an ammonia leak. This achieves rapid and automatic submersion cooling and dilution absorption of the leak source at its source, significantly shortening emergency response time and substantially improving the system's inherent safety level and the efficiency of leak emergency handling. By incorporating a waste gas purification unit including an ammonia cracking tank, ammonia-containing tail gas is efficiently decomposed under high temperature and catalyst conditions, achieving thorough purification and safe treatment of the waste gas. Through a safety interlock control unit, multiple safety aspects, including explosion-proof isolation, leak detection, emergency response, pipeline shut-off, and waste gas purification, are organically integrated into a coordinated whole, achieving automated safety management throughout the entire process. This improves the reliability and efficiency of the overall emergency response and realizes integrated and coordinated control of the system.

Description

Technical Field

[0001] This application relates to the field of hazardous chemical safety technology, and in particular to an integrated control system and method for the safe storage and use of liquid ammonia. Background Technology

[0002] Liquid ammonia, an industrial raw material widely used in chemical and materials processing fields, is toxic, corrosive, flammable, and explosive. Therefore, safe management during its storage and use is crucial. However, existing safety management measures for liquid ammonia have many shortcomings.

[0003] First, regarding physical protection, existing liquid ammonia storage areas mostly use ordinary building structures, which are weak in terms of explosion-proof, fire-proof, lightning protection, and anti-static capabilities, making it difficult to effectively contain and control accidents. Second, in terms of emergency response, when liquid ammonia leaks occur, current technologies generally lack automated means to quickly control leaks at the source, relying mostly on manual operation or spraying with limited effectiveness, resulting in severely delayed response and low handling efficiency. Third, regarding pipeline safety, due to improper material selection or connection methods, ammonia delivery pipelines themselves become high-risk points for leaks. Furthermore, in terms of environmental treatment, the ammonia-containing exhaust gas generated during the use of liquid ammonia is often not thoroughly treated. Direct emissions not only pollute the environment, but improper handling of its cracking products (such as hydrogen) can also lead to safety risks such as secondary explosions.

[0004] More importantly, existing safety subsystems such as detection alarms, ventilation, sprinklers, and gas supply cutoff mostly operate independently, lacking an integrated and coordinated control strategy, and thus failing to form a unified emergency response in emergencies. Therefore, existing technologies generally suffer from technical problems such as delayed emergency response to liquid ammonia leaks, inability to quickly control leaks at the source, incomplete waste gas treatment posing secondary safety risks, and a lack of coordinated operation among various safety subsystems. A comprehensive solution is urgently needed, especially a safety control technology capable of automatically and rapidly suppressing leaks when they occur. Summary of the Invention

[0005] In view of this, this application provides an integrated control system for the safe storage and use of liquid ammonia, aiming to solve the technical problems existing in the prior art, such as delayed emergency response to liquid ammonia leaks, low processing efficiency, incomplete waste gas treatment, and lack of coordination among various safety subsystems. Specifically, by setting up an automatically sinking liquid ammonia container support structure, the leak source can be quickly immersed in the absorption medium after a leak occurs, reducing the ammonia release rate from the source. In addition, this application also provides a method applicable to the aforementioned integrated control system for the safe storage and use of liquid ammonia.

[0006] To achieve the above objectives, this application provides the following technical solution: An integrated control system for the safe storage and use of liquid ammonia includes: Explosion-proof isolation unit; An emergency unit for liquid ammonia storage is installed inside the explosion-proof isolation unit and is used for emergency handling of leaked liquid ammonia cylinders. A pipeline delivery unit for transporting liquid ammonia, and the pipeline delivery unit is equipped with a shut-off valve; The exhaust gas purification unit is used to purify the ammonia-containing tail gas generated during the use of liquid ammonia. A safety interlock control unit is electrically connected to the liquid ammonia storage emergency unit, the pipeline transportation unit, and the waste gas purification unit to achieve coordinated operation. The liquid ammonia storage emergency unit includes a water tank for containing emergency treatment liquid and a lifting support frame installed in the water tank. The water tank is filled with water or a solution containing an absorbent. The lifting support frame is used to support the liquid ammonia cylinder and, when an ammonia leak signal is detected, drives the entire liquid ammonia cylinder to sink into the water tank, so that the liquid ammonia cylinder's outlet valve or the entire liquid ammonia cylinder is immersed in the absorbent medium to suppress the volatilization and diffusion of ammonia. The safety interlock control unit includes an ammonia leak detector and an interlock controller. The interlock controller is used to control the lifting support frame to sink when the ammonia leak detector detects an ammonia leak. The exhaust gas purification unit includes a heating furnace and an ammonia cracking tank filled with a catalyst, which is disposed in the heating furnace. The ammonia cracking tank is used to catalytically decompose ammonia-containing tail gas at high temperature.

[0007] Optionally, in the above-mentioned integrated control system for the safe storage and use of liquid ammonia, the system further includes an emergency ventilation fan; the safety interlock control unit is equipped with at least two levels of alarm thresholds; the linkage controller executes a graded interlock control strategy based on changes in ammonia concentration, and is configured as follows: When the ammonia concentration reaches the first-level warning threshold, an audible and visual alarm is triggered and / or the emergency ventilation fan is activated. When the ammonia concentration reaches the secondary alarm threshold, control the lifting support frame to sink, and / or close the shut-off valve, and / or start the emergency ventilation fan, and / or send a remote notification.

[0008] Optionally, the aforementioned integrated control system for the safe storage and use of liquid ammonia also includes a lightning protection device installed on the explosion-proof isolation unit to prevent lightning strikes from causing an explosion.

[0009] Optionally, the above-mentioned integrated control system for the safe storage and use of liquid ammonia also includes an eyewash station installed next to the personnel evacuation route, the eyewash station having a heating function.

[0010] Optionally, in the above-mentioned integrated control system for safe storage and use of liquid ammonia, the exhaust gas purification unit further includes a burner located downstream of the ammonia cracking tank and equipped with an automatic ignition device, the burner being used to burn the hydrogen produced by cracking.

[0011] Optionally, in the above-mentioned integrated control system for safe storage and use of liquid ammonia, the pipeline of the pipeline conveying unit adopts a sealed connection structure, and the shut-off valve is a pneumatic shut-off valve. The walls of the explosion-proof isolation unit are a combination of steel and concrete, and the floor is made of non-sparking concrete.

[0012] Optionally, in the above-mentioned integrated control system for safe storage and use of liquid ammonia, the liquid ammonia storage emergency unit further includes a spray system, which is connected to the linkage controller to be activated when the ammonia leak detector detects an ammonia leak.

[0013] An integrated control method for the safe storage and use of liquid ammonia, applicable to the aforementioned integrated control system for the safe storage and use of liquid ammonia, includes the following steps: The ammonia concentration is monitored in real time using the ammonia leak detector. When the ammonia concentration is detected to reach the preset emergency threshold, the linkage controller automatically controls the lifting support frame to sink the liquid ammonia cylinder into the water pool for submersion and dilution. The exhaust gas purification unit is controlled by the safety interlock control unit to perform exhaust gas purification treatment, including: controlling the heating furnace to heat the ammonia cracking tank to a preset cracking temperature, and then controlling the ammonia-containing tail gas generated during the use of liquid ammonia to be transported into the ammonia cracking tank for catalytic cracking after the preset cracking temperature is reached.

[0014] Optionally, in the above-mentioned integrated control method for the safe storage and use of liquid ammonia, the system further includes an emergency ventilation fan, and the steps to be performed when the ammonia concentration reaches a preset emergency threshold specifically include: When the ammonia concentration is detected to reach the first-level warning threshold, a first-level response action is executed, including triggering an audible and visual alarm and / or starting the emergency ventilation fan. When the ammonia concentration is detected to reach the secondary alarm threshold, a secondary response action is executed, including controlling the lowering of the lifting support frame, and / or closing the shut-off valve, and / or starting the emergency ventilation fan for ventilation.

[0015] Optionally, in the above-mentioned integrated control method for the safe storage and use of liquid ammonia, the preset pyrolysis temperature is 850°C, and the catalyst is a nickel catalyst.

[0016] This application provides an integrated control system for the safe storage and use of liquid ammonia. By setting up an emergency unit for liquid ammonia storage, specifically a lifting support frame that automatically lowers the liquid ammonia cylinder into a water tank upon detection of an ammonia leak, it achieves rapid and automatic submersion cooling and dilution absorption of the leak source at its source. Compared to traditional spraying methods, this significantly shortens the emergency response time, effectively suppresses the volatilization and diffusion of toxic gases, and significantly improves the inherent safety level of the system and the efficiency of leak emergency handling. By setting up a waste gas purification unit including an ammonia cracking tank, ammonia-containing tail gas is efficiently decomposed under high temperature and catalyst action, and the hydrogen produced by cracking is treated by a burner. This not only greatly increases the ammonia decomposition rate, achieving harmless emission of tail gas and meeting environmental protection requirements, but also eliminates the risk of secondary explosions due to hydrogen accumulation, achieving thorough purification and safe treatment of waste gas. Through a safety interlock control unit, multiple safety aspects such as explosion-proof isolation, leak detection, emergency response, pipeline shut-off, and waste gas purification are organically integrated into a coordinated whole. This changes the traditional situation where safety facilities operate independently, achieving automated safety management throughout the entire process, improving the reliability and efficiency of the overall emergency response, and realizing integrated and coordinated control of the system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 A flowchart of the integrated control system for the safe storage and use of liquid ammonia provided in this application; Figure 2 This is a structural schematic diagram of the liquid ammonia storage emergency unit provided in this application; Figure 3 A structural schematic diagram of the heating furnace body and pipeline conveying unit provided in this application; Figure 4 This is a schematic diagram of the ammonia cracking tank for treating tail gas provided in this application.

[0019] exist Figures 1-4 middle: 1. Water tank; 2. Lifting support frame; 3. Sprinkler system; 4. Leakage alarm system; 5. Exhaust fan; 6. Lightning arrester; 7. Pressure reducing valve; 8. Ammonia drying tank; 9. Heating furnace body; 10. Exhaust pipe; 11. Exhaust stack; 12. Ammonia cracking tank. Detailed Implementation

[0020] This application provides an integrated control system for the safe storage and use of liquid ammonia, aiming to solve the technical problems existing in the prior art, such as delayed emergency response to liquid ammonia leaks, low processing efficiency, incomplete waste gas treatment, and lack of coordinated operation among various safety subsystems. In addition, this application also provides a method applicable to the aforementioned integrated control system for the safe storage and use of liquid ammonia.

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] like Figures 1-4 As shown, this application provides an integrated control system for the safe storage and use of liquid ammonia, used to automatically suppress the leakage source when an ammonia leak is detected. The system includes: an explosion-proof isolation unit; a liquid ammonia storage emergency unit, located within the explosion-proof isolation unit, used for emergency handling of leaking liquid ammonia cylinders; a pipeline delivery unit for transporting liquid ammonia, equipped with a shut-off valve; an exhaust gas purification unit for purifying ammonia-containing tail gas generated during the use of liquid ammonia; and a safety interlock control unit, electrically connected to the liquid ammonia storage emergency unit, pipeline delivery unit, and exhaust gas purification unit to achieve coordinated operation. The liquid ammonia storage emergency unit includes components for... The system includes a water tank 1 for containing emergency treatment liquids and a lifting support frame 2 installed within the water tank 1. The water tank 1 is filled with water or a solution containing absorbent. The lifting support frame 2 is used to support the liquid ammonia cylinder and, upon detecting an ammonia leak signal, drives the entire liquid ammonia cylinder to sink into the water tank 1, immersing the liquid ammonia cylinder's outlet valve or the entire liquid ammonia cylinder in the absorbent medium to suppress ammonia volatilization and diffusion. The safety interlock control unit includes an ammonia leak detector and a linkage controller. The linkage controller is used to control the lifting support frame 2 to sink when the ammonia leak detector detects an ammonia leak. The exhaust gas purification unit includes a heating furnace body 9 and an ammonia cracking tank 12 filled with a catalyst installed within the heating furnace body 9. The ammonia cracking tank 12 is used to catalytically decompose ammonia-containing tail gas at high temperatures.

[0023] Specifically, the system includes an explosion-proof isolation unit, a liquid ammonia storage emergency unit, a safety interlock control unit, a pipeline transportation unit, an exhaust gas purification unit, and a manual emergency unit. The safety interlock control unit, as the control core, connects to the actuators and sensors within each unit via electrical signals to collect information and issue commands. The physical flow of liquid ammonia occurs sequentially through the liquid ammonia storage emergency unit and the pipeline transportation unit, with the exhaust gas generated during its use ultimately being sent to the exhaust gas purification unit for treatment.

[0024] In the aforementioned system, a central safety interlocking control unit coordinates and schedules multiple functional sub-units to form an organic whole. Specifically, the system includes an explosion-proof isolation unit providing basic physical protection, a liquid ammonia storage emergency unit for rapid response at the source in the event of a leak, a pipeline transportation unit for the safe delivery of liquid ammonia, and a waste gas purification unit for the harmless treatment of process tail gases. All these units operate under the unified coordination of the safety interlocking control unit, thereby achieving efficient collaborative operation.

[0025] In the aforementioned system, the explosion-proof isolation unit is designed to provide a robust physical barrier for the entire system, responding to extreme situations such as fires and explosions. By employing specific building structures and materials (described later), this unit can limit the potential impact of accidents to a minimum, preventing their spread to the external environment. This is a fundamental measure to address the inadequate protection of storage areas in the background technology. Constructing such a controlled environment creates the preconditions for the effective implementation of subsequent automated emergency response measures.

[0026] The liquid ammonia storage emergency unit is the core of the emergency response mechanism in this application. Its purpose is to change the passive emergency response mode in existing technologies, which relies on manual intervention and is slow to respond. This unit achieves rapid and proactive intervention in leak accidents by setting up a lifting support frame 2 that automatically submerges the leak source (liquid ammonia cylinder) into a water tank 1. Once a leak occurs, the system no longer relies solely on methods such as spraying to dilute ammonia in the air, but directly floods, cools, and absorbs the leak source itself, thereby controlling the situation in the shortest possible time. This solves the key problems of inadequate and inefficient emergency response in the prior art.

[0027] It should be noted that after the ammonia is dried in the ammonia drying tank 8, it is fed into the waste gas purification unit through the pipeline transportation unit.

[0028] The pipeline delivery unit aims to address the problem in the prior art where pipelines themselves are prone to becoming leak sources. By employing corrosion-resistant materials, more reliable connection processes, and incorporating fast-response shut-off valves, this unit reduces the probability of pipeline leaks from the design stage. Simultaneously, the linkage between the shut-off valve and the safety interlock control unit ensures that the gas supply can be quickly cut off if a leak is detected at any point in the system, preventing further escalation of the accident.

[0029] The exhaust gas purification unit constitutes the final link in the safety and environmental protection closed loop of this application. Its purpose is to completely solve the problem of incomplete treatment of ammonia-containing exhaust gas in the background technology, which may even cause secondary safety risks (such as hydrogen explosion). By adopting high-temperature catalytic cracking technology, this unit can efficiently decompose toxic ammonia into nitrogen and hydrogen. The hydrogen is further converted into water vapor through combustion, realizing the harmless emission of exhaust gas and reflecting the design concept of emphasizing both safety and environmental protection in modern industrial production.

[0030] The exhaust gas purification unit heats the ammonia-containing tail gas to 800-900℃, where it undergoes cracking under the action of a catalyst. This specific temperature range is an optimized interval selected based on the kinetics and thermodynamic equilibrium of the ammonia cracking reaction. Too low a temperature results in a slow reaction rate and incomplete ammonia decomposition, leading to non-compliance with emission standards; too high a temperature significantly increases energy consumption and places more stringent requirements on equipment materials. By precisely controlling the temperature at 800-900℃, a high economic benefit can be achieved while ensuring an ammonia decomposition rate (e.g., exceeding 99%), solving the problems of incomplete exhaust gas treatment or excessive energy consumption in existing technologies.

[0031] The safety interlock control unit is the "brain" of the entire system, aiming to overcome the situation in the prior art where various safety facilities operate independently and cannot form a synergy. This unit uses an ammonia leak detector to sense environmental risks in real time and, based on preset logic, automatically issues coordinated action commands to the liquid ammonia storage emergency unit, pipeline delivery unit, ventilation equipment in the explosion-proof isolation unit, and exhaust gas purification unit. This integrated, coordinated control is the core of achieving the rapid, efficient, and automated emergency response of this invention, solving the fundamental defect of poor coordination in the prior art's safety systems.

[0032] In summary, by setting up an emergency liquid ammonia storage unit, especially the lifting support frame 2 that automatically lowers the liquid ammonia cylinder into the water tank 1 when an ammonia leak is detected, rapid and automatic submersion cooling and dilution absorption of the leak source are achieved from the source. Compared with traditional spraying methods, this greatly shortens the emergency response time, effectively suppresses the volatilization and diffusion of toxic gases, and significantly improves the inherent safety level of the system and the efficiency of leak emergency handling. By setting up a waste gas purification unit including an ammonia cracking tank 12, ammonia-containing tail gas is efficiently decomposed under high temperature and catalyst action, and the hydrogen produced by cracking is treated by a burner. This not only greatly increases the ammonia decomposition rate and achieves harmless emission of tail gas, meeting environmental protection requirements, but also eliminates the risk of secondary explosion caused by hydrogen accumulation, achieving thorough purification and safe treatment of waste gas. Through the safety interlock control unit, multiple safety links such as explosion-proof isolation, leak detection, emergency response, pipeline cut-off, and waste gas purification are organically integrated into a coordinated whole. This changes the traditional situation of individual safety facilities operating independently, realizes automated safety management throughout the entire process, improves the reliability and efficiency of the overall emergency response, and achieves integrated and coordinated control of the system. In an optional embodiment, to achieve more refined emergency management, the system also includes an emergency ventilation fan; the safety interlock control unit is set with at least two alarm thresholds; the linkage controller executes a graded interlock control strategy according to changes in ammonia concentration, and is configured to: trigger an audible and visual alarm and / or start the emergency ventilation fan when the ammonia concentration reaches the first-level warning threshold; and control the lifting support frame 2 to sink and / or close the shut-off valve and / or start the emergency ventilation fan and / or send a remote notification when the ammonia concentration reaches the second-level alarm threshold.

[0033] It should be noted that the linkage controller is electrically connected to the audible and visual alarm. When the ammonia concentration reaches the first-level warning threshold, the linkage controller triggers the audible and visual alarm, causing the alarm to sound and light.

[0034] Specifically, the purpose of this tiered response mechanism is to take different levels of action based on the severity of the leak, avoiding overreacting or underreacting. For example, if the ammonia concentration only reaches the first-level warning threshold, the system may only trigger an audible and visual alarm to alert on-site personnel and activate the emergency ventilation fan for dilution—a low-cost, preventative intervention. In this way, minor leaks can be handled without interrupting normal production, improving the system's operational economy and flexibility.

[0035] When the ammonia concentration continues to rise and reaches the more dangerous secondary alarm threshold, the linkage controller will execute a higher-level emergency response. This includes, but is not limited to: controlling the lowering support frame 2 to submerge the leak source, closing the shut-off valve on the pipeline delivery unit to cut off the gas supply, starting or continuously operating the emergency ventilation fan to dilute the diffused ammonia to the greatest extent, and simultaneously sending an alarm to management personnel via the remote notification module. The coordinated execution of this series of combined actions constitutes a decisive, comprehensive, and three-dimensional response to a serious leak accident. By employing multiple measures, it ensures that the damage from the accident is minimized in the shortest possible time, solving the problems of delayed emergency response and limited methods in the background technology.

[0036] In one example, the ammonia leak detectors are explosion-proof, with a range of 0-1000ppm and an accuracy of ±3%FS. Two detectors are installed in the liquid ammonia cylinder storage area, and one is installed above the manifold cabinet, at a height of 1.5m. The ammonia leak detectors have two alarm thresholds: the first-level warning threshold is 25ppm, which, when triggered, activates an audible and visual alarm with a sound intensity of 90dB and a flashing frequency of 1Hz. The central control screen displays the alarm location, and the normal ventilation fan speed increases to 100%. The second-level alarm threshold is 200ppm, which, when triggered, activates the linkage controller to automatically interlock, cuts off the ammonia pipeline inlet valve, starts the lowering of the lifting support frame 2, turns on the sprinkler system 3 (spraying water for 10 minutes), and activates the emergency ventilation fan. At the same time, the remote notification module sends an SMS alarm to the designated terminal, triggering the emergency system.

[0037] In optional embodiments, a lightning protection device is also included on the explosion-proof isolation unit to prevent lightning strikes from causing an explosion. Specifically, the lightning protection device includes a hot-dip galvanized lightning rod installed on the roof, arranged in a grid structure along the eaves and ridge. Four down conductors are installed, made of round steel, with test cards installed 0.5m above the ground. The grounding electrode is made of hot-dip galvanized angle steel, 2.5m long, spaced 5m apart, with a grounding resistance not exceeding 10Ω. The anti-static system includes an equipotential bonding network composed of 40×4mm galvanized flat steel. All metal equipment inside the isolation room is connected to the grounding main line, with 6mm² copper braided wire bridging the flange connections, and a transition resistance not exceeding 0.03Ω. The ground is covered with anti-static floor paint, and anti-static mats are installed at the entrance, with a surface resistance range of 1×10⁻⁶. 6 -1×10 9 Ω.

[0038] A surge arrester 6 is also installed in the explosion-proof isolation unit.

[0039] Liquid ammonia is flammable and explosive. The high-temperature arc or spark generated by a lightning strike can easily ignite leaked ammonia or hydrogen (generated from waste gas treatment). Lightning protection devices can effectively intercept lightning strikes and safely conduct the lightning current to the ground, fundamentally breaking the accident chain of "lightning strike-spark-explosion".

[0040] In an optional embodiment, an eyewash station is also included, located beside an evacuation route, and the eyewash station has a heating function. The eyewash station adopts a composite structure, including an eyewash nozzle and a shower head. The main body is made of stainless steel, while the nozzles and valves are made of corrosion-resistant materials. The nozzle orifice diameter is φ6mm, and it features an anti-clogging design. The eyewash nozzle has a flow rate of not less than 1.5L / min and a continuous water supply time of not less than 15 minutes; the shower head has a flow rate of not less than 75L / min, a water pressure range of 0.2-0.4MPa, and is connected to a fire-fighting water system.

[0041] The eyewash station must be located no more than 10 meters away from the liquid ammonia storage and operation area, meeting the 10-second arrival requirement. There must be no obstructions within 1 meter of the station, and the operating space must be at least 0.8m x 0.8m, avoiding areas directly affected by a liquid ammonia leak. The eyewash station uses a foot-operated valve with a dust cover, a response time of no more than 1 second, and an operating force of no more than 15N. This significantly lowers the operational threshold, ensuring rapid initiation of flushing even in panic or severe pain.

[0042] In winter, an electric heating device is installed to maintain the water temperature between 5-40℃. The heating cable has a power of 20W / m and is wrapped with 50mm thick insulation cotton. This solves the problem of eyewash stations freezing and failing in cold winters in cold regions. The water temperature is maintained within the physiological temperature range suitable for the human body, avoiding cold shock or secondary frostbite caused by low-temperature water, ensuring the effectiveness of emergency measures, and meeting ergonomic requirements.

[0043] The eyewash station base is fixed to a concrete foundation with expansion bolts. The concrete foundation thickness is not less than 100mm, the bolt spacing is 300mm×300mm, and the gap between the base and the ground does not exceed 2mm. The water inlet pipe connected to the eyewash station is made of seamless stainless steel. The eyewash station is independently connected to the fire water network and is controlled by a separate ball valve. The pipe is installed with a 1% slope towards the eyewash station. The drain outlet of the eyewash station is connected to a stainless steel drain pipe, which is connected to an emergency wastewater collection tank. The drain pipe is equipped with a water seal bend to prevent odors from rising. A conspicuous identification sign made of reflective material is installed 200mm above the eyewash station.

[0044] Thus, when personnel are covered in splashes from a leaked ammonia, a high-flow-rate shower can quickly penetrate clothing and dilute the high concentration of ammonia on the skin; when only the eyes are exposed, an eyewash station can precisely rinse the conjunctival sac. This dual configuration ensures immediate and effective first aid in cases of varying degrees of injury, preventing the chemical burns from worsening.

[0045] Furthermore, the exhaust gas purification unit also includes a burner equipped with an automatic ignition device located downstream of the ammonia cracking tank 12. The burner is used to burn the hydrogen produced during the cracking process. The ammonia cracking reaction generates a large amount of hydrogen, which is a flammable and explosive gas. If directly emitted or improperly treated, it can easily mix with air at the exhaust port to form an explosive gas. By installing a burner with an automatic ignition device, the hydrogen in the cracking products can be safely and controllably burned into harmless water vapor during discharge. This design completely eliminates the risk of secondary explosions, forming a complete safety closed loop from "toxic gas treatment" to "flammable gas treatment."

[0046] In optional embodiments, to improve system reliability from the source, the pipeline of the pipeline delivery unit adopts a sealed connection structure, preferably using argon arc welding, and the shut-off valve is a pneumatic shut-off valve. This solves the problem of loosening and leakage points in existing threaded or flanged connections under long-term corrosive environments. Argon arc welding can form a dense, continuous metallurgical bond, with sealing performance and strength far exceeding that of mechanical connections, thus greatly reducing the risk of pipeline leakage. Simultaneously, the shut-off valve is preferably a pneumatic shut-off valve, which, compared to manual valves or some electric valves, has advantages such as fast response speed, large actuation torque, and ease of remote and automatic control. By linking the pneumatic shut-off valve with the safety interlock control unit, rapid shut-off within milliseconds after receiving an alarm signal is achieved, buying valuable time to prevent the accident from escalating.

[0047] In an optional embodiment, to enhance the system's basic physical protection capabilities, the walls of the explosion-proof isolation unit are a combination of steel and concrete, and the floor is made of non-sparking concrete. This addresses the problem of weak explosion-proof and impact resistance of ordinary walls in existing technologies. The steel structure provides excellent toughness and resistance to deformation, while the concrete provides mass and rigidity; the combination effectively resists the shock waves generated by an internal explosion. Simultaneously, the non-sparking concrete floor prevents sparks from being generated by dragging or impacting tools and equipment, thus eliminating the risk of igniting potentially accumulated ammonia-air mixtures in the explosion environment. This represents a significant improvement in the safety level of hazardous chemical work sites.

[0048] In an optional embodiment, to enhance the handling capacity for ammonia gas that has diffused into the air, the liquid ammonia storage emergency unit also includes a spray system 3. The spray system 3 is connected to a linkage controller to activate when an ammonia leak detector detects an ammonia leak. By connecting the spray system 3 to the linkage controller, the spray system 3 can be activated synchronously or asynchronously with the lowering action of the lifting support frame 2 when an ammonia leak is detected. This complements the core measure of flooding the leak source with the lifting support frame 2. Even if the leak source is flooded, ammonia gas that has already leaked into the environment before flooding still exists. The spray system 3, by spraying water mist, can effectively absorb and dilute this airborne ammonia gas, reducing its concentration, thereby creating a safer environment for personnel evacuation and subsequent treatment, achieving "dual control" of the leak from its source to the environment.

[0049] In one example, the explosion-proof isolation unit is constructed as an independent isolation room, with dimensions of 5.0m × 4.0m × 3.5m. The concrete walls are 200mm thick, and the steel frame uses I-beams (vertical ribs φ12 spaced 150mm, horizontal ribs φ10 spaced 200mm). The floor is 150mm thick non-sparking fine aggregate concrete with a 0.5% drainage slope. Two explosion-proof axial flow fans are installed on the roof (normal ventilation 17.1 times / hour, emergency ventilation 28.6 times / hour). The lightning protection system grounding resistance is ≤8Ω, and the anti-static system forms an equipotential network through galvanized flat steel, with a transition resistance ≤0.03Ω. The walls of the explosion-proof isolation unit use a combination of a steel frame and concrete with a thickness of not less than 200mm to provide excellent impact resistance, while also offering explosion-proof, fireproof, and seismic performance. The ground is paved with 150 mm thick non-sparking fine aggregate concrete, with a flatness error of no more than 3 mm / m, and a drainage slope is provided so that wastewater can flow smoothly to the drain outlet.

[0050] The isolation room itself is equipped with double doors, the door size of which meets the requirements for forklift transport of liquid ammonia cylinders. The double doors are equipped with explosion-proof door closers and access control modules. The access control module can record card swipe operation data, and the keys are kept by designated personnel. The ventilation system includes two normal ventilation fans and two emergency ventilation fans arranged symmetrically at the top. The normal ventilation fans have an air exchange rate of no less than 6 times / hour, and the emergency ventilation fans have an air exchange rate of no less than 12 times / hour. The fan motors are explosion-proof, and the power supply is connected to an emergency power supply device with a backup power time of no less than 30 minutes to ensure that ammonia does not accumulate.

[0051] Water tank 1 is constructed from 304 stainless steel plates, with a bottom plate thickness of 6mm and side plate thickness of 5mm. The tank body is reinforced externally and has an internal I-beam support frame. The horizontal I-beam spacing is 500mm, the longitudinal I-beam spacing is 1000mm, and the vertical support angle steel spacing is 1000mm. The tank body passed a 120-hour leak-proof test, showing no leakage or visible deformation. The inner wall of water tank 1 is sequentially coated with epoxy zinc-rich primer, epoxy micaceous iron oxide intermediate paint, and epoxy resin topcoat, with a total dry film thickness of 250μm. The outer wall of water tank 1 is coated with epoxy zinc-rich primer and acrylic polyurethane topcoat, with a total dry film thickness of 220μm. The outer wall is also wrapped with an ultra-thin steel structure fireproof coating with a fire resistance limit of 1.5 hours. The external dimensions of pool 1 are 3000mm×2000mm×1500mm, with an effective volume of 9m³. The pool wall is 300mm above the ground to prevent rainwater backflow. The foundation is made of plain concrete with a thickness of 200mm. The length and width are each 300mm larger than pool 1. Anchor bolts are pre-embedded to fix the bottom plate of pool 1.

[0052] The absorption medium in pool 1 can be water, an acidic solution, or other liquids capable of absorbing ammonia.

[0053] The water tank 1 has a drain outlet at its bottom, using a DN80 stainless steel flange interface. The bottom of the tank has a 1% slope to guide the drain outlet. A minimum platform is constructed at the bottom of water tank 1. When the wastewater height exceeds 200mm, the stainless steel submersible pump automatically activates, discharging the wastewater into the centralized sewage pipeline. The sprinkler system 3 includes a DN65 galvanized steel pipe network and pendant sprinklers. The sprinkler spacing is 3.0m, the working pressure is 0.4MPa, and the spray intensity is not less than 6L / min. The facility is 1,000 square meters in size and is linked to a fire pump. It is also equipped with mobile fire-fighting equipment, including four dry powder fire extinguishers and two fire sandboxes, each containing a fire shovel.

[0054] The lifting support frame 2 is an electric chain type (in other embodiments, the lifting support frame 2 can be hydraulically driven, electrically driven, or pneumatically driven), with a load capacity of 500kg, a lifting speed of 0.2m / s, and platform dimensions of 1.8m × 1.2m. A liquid ammonia bottle fixing slot is welded to the surface, with a slot spacing of 1.0m, matching the liquid ammonia bottle base. A rubber buffer pad is provided inside the slot. The guide rails of the lifting support frame 2 are made of 20# channel steel, spaced 1.5m apart, with limit switches on both sides. The upper limit is 1.0m, and the lower limit is -1.0m, with a positioning accuracy of no more than 5mm. Under normal conditions, the liquid ammonia bottle is fixed to the platform, with the bottle opening 240mm from the pool opening, and not in contact with water. In the event of a leak, the platform sinks to the bottom of the pool within 30 seconds, ensuring the bottle opening is submerged to a depth of no less than 100mm.

[0055] Sprinkler system 3 consists of a DN65 galvanized steel pipe network with a water spray intensity ≥6L / min ㎡, fire pump flow rate 20L / s; drainage device with 1% slope, submersible pump automatically starts when wastewater level ≥200mm.

[0056] The safety interlock control unit includes an ammonia leak detector, an audible and visual alarm, a linkage controller, and a video monitoring module. The ammonia leak detectors are explosion-proof, with a range of 0-1000ppm and an accuracy of ±3%FS. Two detectors are installed in the liquid ammonia cylinder storage area, and one is located above the manifold, at a height of 1.5m. The ammonia leak detectors can employ electrochemical, infrared, or semiconductor sensors.

[0057] The ammonia leak detector is equipped with two alarm thresholds: the first-level warning threshold is 25ppm, which triggers an audible and visual alarm with a sound intensity of 90dB and a flashing frequency of 1Hz. The central control screen displays the alarm location, and the normal ventilation fan speed is increased to 100%. The second-level alarm threshold is 200ppm, which triggers an automatic interlocking mechanism that shuts off the ammonia pipeline inlet valve, starts the lowering of the lifting support frame 2, turns on the sprinkler system 3 (spraying water for 10 minutes), and activates the emergency ventilation fan. At the same time, the remote notification module sends an SMS alarm to the designated terminal, triggering the emergency system.

[0058] The safety interlock control unit is equipped with three explosion-proof ammonia detectors; the linkage controller synchronously controls the lifting frame, sprinkler system, emergency fan, and remote SMS notification; the video surveillance storage time is ≥30 days.

[0059] The video surveillance module includes one explosion-proof camera equipped with an IP66 explosion-proof housing, a resolution of 1080P, video signals connected to the security system, storage time of no less than 30 days, and automatic capture and saving of key frames when a leakage alarm is triggered.

[0060] The pipeline delivery unit includes delivery pipes and a manifold, and is responsible for safely delivering liquid ammonia from the liquid ammonia cylinder to the point of use. The main pipeline can use φ57×3.5mm high-temperature resistant stainless steel pipe, and the branch pipelines use φ25×2.5mm high-temperature resistant stainless steel pipe. The connection method is argon arc welding butt joint, and the weld seam is 100% penetrant testing qualified. Threaded or flanged connections are prohibited to eliminate possible leakage points caused by flanges or threaded connections. The manifold has dimensions of 2.0m×0.8m×1.8m and integrates multiple specifications of flow meters and pressure sensors (accuracy ≥0.5 grade) for ammonia, nitrogen, etc.

[0061] Each branch of the pipeline is equipped with a double shut-off valve, including an upstream manual ball valve and a downstream pneumatic shut-off valve. The pneumatic shut-off valve has a response time of no more than 5 seconds. An ammonia-specific pressure reducing valve 7 is installed after the valve, which can reduce the inlet pressure from 1.6MPa to the outlet pressure of 0.3MPa with an accuracy of ±1%. A DN20 vent valve with a blind flange is installed at the highest point of the pipeline, and a DN15 drain valve is installed at the lowest point, which is connected to the wastewater collection tank.

[0062] The aforementioned combiner cabinet is made of Q235B steel, 4mm thick, with an epoxy resin anti-corrosion coating. It features a double-layer explosion-proof glass observation window with a light transmittance of no less than 85%, and a cable pass-through hole at the bottom, equipped with an explosion-proof gland. The combiner cabinet is internally divided into an instrument area, a control area, and a safety area. The instrument area houses flow meters, including ammonia, air, nitrogen, and argon flow meters. The control area is equipped with pressure sensors, on / off solenoid valves, and a 4-way interlock with the leak alarm system. The safety area has a miniature ammonia detector at the top, with a range of 0-500ppm, and a 5-way interlock with the exhaust fan, providing forced ventilation for 15 minutes in case of a leak.

[0063] The pipeline flow of the above-mentioned manifold is as follows: liquid ammonia cylinder → manual ball valve → pressure reducing valve 7 → main inlet valve of manifold → branch (manual ball valve / pneumatic shut-off valve) → pressure sensor → flow meter → main outlet valve of manifold (on / off solenoid valve) → equipment. The accuracy of the pressure sensor is not less than 0.5 grade, the range is 0~1MPa, the solenoid valve is DC24V explosion-proof type, and the response time does not exceed 5 seconds.

[0064] The exhaust gas purification unit is used to treat ammonia-containing tail gas generated during the process. In this embodiment, a WQJ-5 type tail gas purification device is used, consisting of a heating furnace body 9, an ammonia cracking tank 12, electric heating elements, and an exhaust stack 11. The outer shell of the heating furnace body 9 is made of Q235 steel plate with a thickness of 4mm, and the interior is filled with aluminum silicate fiber modules with a density of 128kg / m³ and a thermal conductivity ≤0.04W / (m³). K), the insulation layer is 300mm thick, and the surface temperature rise of the furnace body does not exceed 40℃; the bottom of the furnace body adopts thick channel steel in the shape of a grid, with multiple layers of annular reinforcing rings inside, and the exterior of the furnace body is painted with two coats of primer and two coats of topcoat, and high-temperature paint is used around the furnace door.

[0065] The above-mentioned heating element uses 0Cr25Al5 alloy wire with a diameter of 3mm and a spiral diameter of 50mm. It is independently controlled in one zone with a total power of 7kW. It is equipped with a main controller and a monitoring instrument, with a temperature control accuracy of ≤±1℃, a heating rate of no more than 10℃ / min, and an empty furnace heating time of no more than 2 hours.

[0066] The ammonia cracking tank 12 is made of high-temperature resistant stainless steel and filled with nickel catalyst. Ammonia-containing tail gas is introduced into the tail gas purification device through a φ50mm stainless steel pipe. It is first heated to 300℃ in the preheating section, and then enters the ammonia cracking tank 12 to undergo a cracking reaction at 850℃, decomposing into hydrogen and nitrogen with a decomposition rate of not less than 99%. The decomposed hydrogen is automatically combusted at the outlet with an outlet temperature of not less than 600℃, producing water. Finally, the tail gas is discharged through a 15m high exhaust stack 11. A flame arrester is installed at the outlet of the exhaust stack 11 to prevent backfire.

[0067] Specifically, the ammonia discharged from the liquid ammonia storage emergency unit is preheated by the heating furnace 9 and then enters the ammonia cracking tank 12. It should be noted that pressure gauges and flow meters are installed in the pipeline to monitor the pressure and flow rate of the ammonia entering the heating furnace 9. After preheating, the ammonia enters the ammonia cracking tank 12 through the exhaust pipe 10 and decomposes into hydrogen and nitrogen within it, with a decomposition rate of not less than 99%. The decomposed hydrogen is automatically combusted at the outlet, with an outlet temperature of not less than 600°C, producing water. Finally, the exhaust gas is discharged through a 15m high exhaust stack 11.

[0068] The manual emergency unit, supplementing the automatic system, features a red explosion-proof emergency button with a lead seal on the control panel. Pressing this button forces all emergency measures to activate, regardless of whether the alarm concentration has been reached, and simultaneously locks the intake valve for 30 minutes to prevent accidental reset. In any extreme situation, on-site personnel do not need to wait for the automatic alarm; they can directly press this button to forcibly trigger all the aforementioned secondary response measures and lock the intake valve for 30 minutes, providing the highest level of safety for personnel evacuation and manual intervention.

[0069] In the existing technology, the specific configuration of the integrated control system for the safe storage and use of liquid ammonia is as follows: Storage area: There is no dedicated explosion-proof isolation room. The wall structure is ordinary brick (120mm thick) without steel reinforcement. The floor is ordinary cement floor with no drainage slope or anti-seepage design. Only one ordinary axial flow fan is configured (air change rate 4 times / hour). There are no lightning protection or anti-static facilities.

[0070] Emergency storage of liquid ammonia: A simple concrete water tank 1 (dimensions 2000mm×1500mm×1000mm) is used, without anti-corrosion treatment, and the welds have not been tested for leakage; the liquid ammonia cylinders are fixed by ordinary brackets without lifting devices, and in case of leakage, they need to be manually moved and immersed in water; there is no automatic sprinkler system 3, and only 2 MF / ABC4 type dry powder fire extinguishers are provided.

[0071] Safety protection: Equipped with one ordinary ammonia detector (range 0-500ppm, accuracy ±5%FS), with only audible and visual alarm function and no linkage control; no video monitoring, and manual notification of management personnel is required after a leak.

[0072] Pipeline transportation: Ordinary carbon steel pipes are used, with flange connections; only a single shut-off valve is used, and the pressure reducing valve has an accuracy of ±3%; there is no manifold cabinet, and the flow meters and pressure gauges are distributed separately without centralized control.

[0073] Waste gas treatment: A simple combustion furnace (rated temperature 700℃, no preheating section and nickel catalyst) is used, with an ammonia decomposition rate of about 85%; the exhaust stack is 11 meters high and has no backfire prevention device.

[0074] Auxiliary facilities: There is no dedicated eyewash station, only a regular faucet in the corner of the laboratory; there is no emergency protective cabinet, and personal protective equipment is stored haphazardly.

[0075] Safety performance of existing systems: Ammonia detector response delay ≥10 seconds after leakage, no automatic gas supply cut-off and flooding measures, manual handling requires 3-5 minutes, ammonia easily accumulates (peak concentration can reach over 500ppm); there have been two minor spark hazards caused by static electricity, and the measured grounding resistance is 15Ω, which does not meet safety requirements.

[0076] Environmental performance: Ammonia concentration in exhaust gas ≥100mg / m³, with a noticeable odor; leakage in water tank 1 causes ground corrosion, and indiscriminate wastewater discharge causes localized pollution. Reliability: Pipeline flange connections leak an average of 2-3 times per year; pressure fluctuation in pressure reducing valve 7 ≥±5%; poor temperature control accuracy of the exhaust gas combustion furnace, with repeated instances of incomplete decomposition, requiring frequent shutdowns for maintenance.

[0077] In contrast, the system described in this application exhibits the following safety performance: Upon triggering a level-two alarm, the gas supply is cut off within 5 seconds; the liquid ammonia cylinder is completely submerged within 30 seconds; and the ammonia concentration drops to below 25 ppm within 10 minutes of emergency ventilation, eliminating the risk of leakage and diffusion, thus improving safety performance. The lightning protection and anti-static system operates continuously without abnormalities, and the grounding resistance remains stable at 6Ω. Environmental performance: After waste gas treatment, the ammonia emission concentration is ≤30mg / m³, the hydrogen volume concentration is ≤1%, and there is no odor. Wastewater is centrally collected and treated, with no leakage or pollution observed. Reliability: After 30 days of continuous operation, the lifting system has undergone 50 trial runs without failure; the leakage alarm linkage test was conducted 3 times, with accurate responses in all cases; pipeline pressure fluctuations are ≤±1%; and the displays on all instruments in the manifold cabinet remain stable.

[0078] As can be seen, this application successfully overcomes the technical shortcomings of existing technologies, such as slow response, high pollution, and susceptibility to failure, through explosion-proof isolation, intelligent interlocking control, high-efficiency purification, and multiple emergency protection technologies. It not only shortens emergency response time by more than 80% but also reduces emission indicators by more than 70%, truly achieving inherent safety and green production in the storage and use of liquid ammonia.

[0079] In another preferred embodiment, based on the above embodiments, the structure of the lifting support frame 2 can be different. For example, instead of the electric chain structure, a hydraulic scissor lift platform can be used. This platform is driven by an independent micro hydraulic station, and its scissor arm structure design makes the platform more evenly stressed and runs more smoothly during lifting, especially suitable for carrying multiple liquid ammonia cylinders or for applications with strict requirements on vibration during lifting. When the secondary alarm is triggered, the linkage controller outputs a signal to the control solenoid valve of the hydraulic station. The solenoid valve actuates, and the hydraulic oil drives the scissor platform to descend smoothly and quickly, which can also sink the liquid ammonia cylinder into the water tank 1 within 30 seconds. This increases the practicality of the system.

[0080] In another preferred embodiment, the process of the waste gas purification unit can be further optimized to reduce energy consumption. In this embodiment, a supported platinum-rhodium alloy catalyst is used in the ammonia cracking tank 12 instead of the traditional nickel catalyst. Since the platinum-rhodium alloy catalyst has extremely high catalytic activity at relatively low temperatures, the rated operating temperature of the ammonia cracking tank 12 can be reduced from 850°C to 800°C. Correspondingly, the rated power of the heating furnace body 9 and the design of the insulation layer can also be optimized to match the lower operating temperature. This scheme significantly reduces the energy consumption of the waste gas treatment unit during long-term operation while still ensuring an ammonia decomposition rate of not less than 99%, providing a more energy-efficient solution.

[0081] An integrated control method for the safe storage and use of liquid ammonia, applicable to the aforementioned system, includes the following steps: real-time monitoring of ammonia concentration via an ammonia leak detector; when the ammonia concentration reaches a preset emergency threshold, automatic control of the lifting support frame 2 via a linkage controller to submerge the liquid ammonia cylinder into the water tank 1 for dilution; and control of the waste gas purification unit via a safety interlock control unit to perform waste gas purification treatment, including: controlling the heating furnace body 9 to heat the ammonia cracking tank 12 to a preset cracking temperature, and then, after reaching the preset cracking temperature, controlling the ammonia-containing tail gas generated during the use of liquid ammonia to be transported into the ammonia cracking tank 12 for catalytic cracking.

[0082] Specifically, the process begins with real-time monitoring of ammonia concentration using an ammonia leak detector, providing the data foundation for proactive early warning and automated response. When the ammonia concentration reaches a preset emergency threshold, the core step of the method is triggered: the lifting support frame 2, controlled by a linkage controller, automatically lowers the liquid ammonia cylinder it carries into a water tank 1 for submersion and dilution. This rapidly controls the leak at its source.

[0083] The method also includes a step of closed-loop control of the waste gas purification unit through a safety interlock control unit. Specifically, this involves first controlling the heating furnace 9 to heat the ammonia cracking tank 12 to a preset cracking temperature, such as 850°C. After confirming that the temperature has stabilized, the valve is then controlled to deliver the ammonia-containing tail gas generated during the use of liquid ammonia to the ammonia cracking tank 12 for catalytic cracking. This "heating first, then gas introduction" control logic aims to ensure that ammonia is always decomposed under optimal process conditions, avoiding problems such as incomplete decomposition and reduced catalyst activity caused by introducing tail gas when the temperature is insufficient, thus ensuring continuous and efficient waste gas treatment.

[0084] Furthermore, in order to achieve refined control that matches the system's hierarchical alarm function, the system also includes an emergency ventilation fan. The specific steps to be performed when the ammonia concentration reaches the preset emergency threshold include: when the ammonia concentration reaches the first-level warning threshold, a first-level response action is performed, including triggering an audible and visual alarm and / or starting the emergency ventilation fan; when the ammonia concentration reaches the second-level alarm threshold, a second-level response action is performed, including controlling the lifting support frame 2 to sink, and / or closing the shut-off valve, and / or starting the emergency ventilation fan for ventilation.

[0085] When the ammonia concentration is detected to reach a low Level 1 warning threshold, the system executes a Level 1 response, which may only include triggering an audible and visual alarm to alert personnel and / or activating emergency ventilation fans for preventative ventilation. This is intended to address initial, minor leak signs with minimal system intervention.

[0086] When the ammonia concentration is detected to reach a higher level of the secondary alarm threshold, a comprehensive secondary response is executed. This includes a series of parallel, automated emergency measures: immediately controlling the lowering of the lifting support frame 2 to address the leak at its source; simultaneously closing the shut-off valve on the pipeline delivery unit to cut off the subsequent ammonia supply; and starting or continuously operating the emergency ventilation fan for powerful ventilation to quickly reduce the ammonia concentration in the environment. This tiered, progressive response strategy makes the entire control method both sensitive and decisive, capable of intelligently allocating system resources according to the risk level.

[0087] In an optional embodiment, to obtain the best waste gas treatment effect, the preset pyrolysis temperature is 850°C, and the catalyst is a nickel catalyst.

[0088] Specifically, the preset pyrolysis temperature is preferably 850℃, and the catalyst filled in the ammonia pyrolysis tank 12 is preferably a nickel catalyst. 850℃ is a balance point verified in industrial practice that balances high decomposition rate and reasonable energy consumption. Nickel catalyst, as a mature, efficient, and relatively low-cost ammonia pyrolysis catalyst, exhibits excellent catalytic activity and stability at this temperature. By incorporating these specific and optimized process parameters into the control method, the present invention ensures that it can consistently achieve the expected environmental protection effects in practical applications.

[0089] More specifically, step 1: normal operation control.

[0090] Explosion-proof isolation unit: The normal ventilation fan runs continuously, maintaining an air exchange rate of no less than 6 times / hour; the access control module records personnel entry and exit data, and the double doors are locked, with only authorized personnel able to unlock them by swiping a card / NFC; the lightning protection and anti-static system works in real time, with the grounding resistance maintained at ≤10Ω, and the equipotential bonding network continuously conducting.

[0091] Liquid ammonia storage emergency unit: The lifting support frame 2 is in the upper limit position, the liquid ammonia bottle is fixed on the platform, the bottle mouth is 240mm away from the pool mouth and does not come into contact with water; the sprinkler system 3 is in standby mode, the fire pump is kept on standby; the submersible pump of the drainage device is in dormant mode, and the wastewater level in the pool 1 is monitored in real time.

[0092] Pipeline delivery unit: The manual ball valve is open, the pneumatic shut-off valve is in the conducting state, and the pressure reducing valve 7 stabilizes the liquid ammonia cylinder outlet pressure at 0.3MPa; the pressure sensor monitors the pipeline pressure in real time, and the data is transmitted to the linkage controller. When the pressure deviates from the range of 0.3MPa±1%, the linkage controller issues an early warning; the flow meter in the manifold measures the flow of each gas in real time, and the signal is connected to the PLC system to realize visual monitoring of the flow.

[0093] Exhaust gas purification unit: The exhaust gas purification device is preheated and started. The electric heating element is energized and heated. The main controller controls the temperature of the preheating section at 300℃ and the temperature of the ammonia cracking tank 12 at 850℃. When the furnace temperature reaches the set value, the ammonia-containing exhaust gas is introduced into the device. The cracked products are burned through the gas outlet. The combustion temperature is maintained at ≥600℃. The exhaust gas is discharged at high altitude through the exhaust stack 11.

[0094] Auxiliary safety facilities: When the eyewash station is in standby mode, the electric heating device will automatically start in winter. The temperature sensor monitors the water temperature in real time. When the water temperature is below 5℃, the heating cable will be powered on to heat the water. When the water temperature is above 40℃, the heating cable will be powered off to maintain the water temperature in the range of 5-40℃.

[0095] Step 2: Leakage classification control.

[0096] Level 1 Warning Trigger (Ammonia Concentration ≥25ppm and <200ppm): ① Safety Interlock Control Unit: Audible and visual alarm activated, sound intensity 90dB, flashing frequency 1Hz; central control screen displays the specific alarm location; video monitoring module automatically captures and saves images of the leak area. ② Explosion-proof Isolation Unit: Normal ventilation fan speed increased to 100% to enhance indoor air circulation and reduce ammonia concentration. ③ Combination Cabinet: If the internal miniature ammonia detector detects a concentration ≥50ppm, exhaust fan 5 is triggered for forced ventilation. After 15 minutes of continuous ventilation, the concentration is re-detected; if the concentration does not meet the standard, operation continues.

[0097] Level 2 Alarm Trigger (Ammonia Concentration ≥ 200 ppm): ① Safety Interlock Control Unit: The remote notification module sends an SMS alarm to the designated terminal, simultaneously triggering the emergency system; the linkage controller activates the emergency interlock of the entire system. ② Liquid Ammonia Storage Emergency Unit: After receiving the linkage signal, the lifting support frame 2 lowers to the lower limit within 30 seconds, and the liquid ammonia cylinder opening is submerged to a depth ≥ 100 mm; the electric valve of the sprinkler system 3 automatically opens, the fire pump starts, and the water spray intensity is ≥ 6 L / min. 3. **Pipeline Delivery Unit:** The pneumatic shut-off valve automatically closes within 5 seconds, cutting off the ammonia gas supply; the solenoid valves in the manifold close simultaneously, blocking the gas delivery path. 4. **Explosion-proof Isolation Unit:** The emergency ventilation fan starts, maintaining an air exchange rate of ≥12 times / hour until the ammonia concentration drops to <25ppm, after which it automatically switches back to normal ventilation mode.

[0098] Step 3: Manual emergency control.

[0099] When operators discover a leak or other emergency, they can press the red mushroom-shaped emergency button on the control panel to forcibly activate the emergency procedure: ① The linkage controller ignores the ammonia concentration detection results and directly triggers all emergency measures corresponding to the level 2 alarm, including closing the pneumatic shut-off valve, lowering the lifting support frame 2, starting the sprinkler system 3, and operating the emergency ventilation fan. ② The air inlet valve is locked for 30 minutes and cannot be manually reset during this period to prevent accidental operation from causing the leak to expand; after 30 minutes, it must be unlocked after manual confirmation of safety.

[0100] In an emergency, operators can wear protective suits and breathing apparatus from the emergency cabinet and use mobile fire-fighting equipment for on-site handling.

[0101] Step 4: Waste gas treatment and control.

[0102] Temperature closed-loop control: The temperature measuring component monitors the temperature of the preheating section, ammonia cracking tank 12 and the outlet in real time, and the data is fed back to the main controller and the monitoring instrument; when the temperature of the preheating section is <300℃ or the temperature of ammonia cracking tank 12 is <850℃, the main controller controls the heating element to increase the power of heating; when the temperature is 5℃ higher than the set value, the power supply of the heating element is cut off to maintain temperature stability.

[0103] Abnormal Handling: If the temperature of ammonia cracking tank 12 is detected to rise or fall abnormally by more than ±10℃, the monitor will issue an alarm; if the combustion temperature at the outlet is <600℃, the linkage controller will close the tail gas inlet valve and stop the tail gas supply until the temperature returns to normal.

[0104] Step 5: Wastewater discharge control.

[0105] After the emergency response to the liquid ammonia leak, the wastewater level in pool 1 is monitored in real time by a level sensor. When the level exceeds 200 mm, the linkage controller starts the submersible pump to discharge the wastewater to the accident wastewater collection pool through the centralized sewage pipeline. When the level drops below 50 mm, the submersible pump automatically stops running.

[0106] During the drainage process, the pH value of the wastewater is monitored in real time. If an abnormality is detected, the linkage controller will issue a prompt and notify personnel to perform neutralization treatment before discharge.

[0107] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0108] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0109] It should also be noted that in the apparatus, equipment, and housing of this application, the components or steps can be disassembled and / or reassembled. These disassemblies and / or reassemblies should be considered as equivalent solutions of this application.

[0110] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0111] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0112] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. An integrated control system for the safe storage and use of liquid ammonia, characterized in that, This system is used to automatically suppress liquid ammonia leaks when an ammonia leak is detected. The system includes: Explosion-proof isolation unit; An emergency unit for liquid ammonia storage is installed inside the explosion-proof isolation unit and is used for emergency handling of leaked liquid ammonia cylinders. A pipeline delivery unit for transporting liquid ammonia, and the pipeline delivery unit is equipped with a shut-off valve; The exhaust gas purification unit is used to purify the ammonia-containing tail gas generated during the use of liquid ammonia. A safety interlock control unit is electrically connected to the liquid ammonia storage emergency unit, the pipeline transportation unit, and the waste gas purification unit to achieve coordinated operation. The liquid ammonia storage emergency unit includes a water tank for containing emergency treatment liquid and a lifting support frame installed in the water tank. The water tank is filled with water or a solution containing an absorbent. The lifting support frame is used to support the liquid ammonia cylinder and, when an ammonia leak signal is detected, drives the entire liquid ammonia cylinder to sink into the water tank, so that the liquid ammonia cylinder's outlet valve or the entire liquid ammonia cylinder is immersed in the absorbent medium to suppress the volatilization and diffusion of ammonia. The safety interlock control unit includes an ammonia leak detector and an interlock controller. The interlock controller is used to control the lifting support frame to sink when the ammonia leak detector detects an ammonia leak. The exhaust gas purification unit includes a heating furnace and an ammonia cracking tank filled with a catalyst, which is disposed in the heating furnace. The ammonia cracking tank is used to catalytically decompose ammonia-containing tail gas at high temperature.

2. The integrated control system for the safe storage and use of liquid ammonia according to claim 1, characterized in that, The system also includes an emergency ventilation fan; the safety interlock control unit is equipped with at least two alarm threshold levels; the linkage controller executes a graded interlock control strategy based on changes in ammonia concentration, and is configured as follows: When the ammonia concentration reaches the first-level warning threshold, an audible and visual alarm is triggered and / or the emergency ventilation fan is activated; When the ammonia concentration reaches the secondary alarm threshold, the lifting support frame is controlled to sink, and / or the shut-off valve is closed, and / or the emergency ventilation fan is started, and / or a remote notification is sent.

3. The integrated control system for the safe storage and use of liquid ammonia according to claim 1 or 2, characterized in that, It also includes a lightning protection device installed on the explosion-proof isolation unit to prevent lightning strikes from causing an explosion.

4. The integrated control system for the safe storage and use of liquid ammonia according to claim 1, characterized in that, It also includes eyewash stations located next to personnel evacuation routes, the eyewash stations having a heating function.

5. The integrated control system for the safe storage and use of liquid ammonia according to claim 1, characterized in that, The exhaust gas purification unit also includes a burner located downstream of the ammonia cracking tank and equipped with an automatic ignition device, the burner being used to burn the hydrogen produced by cracking.

6. The integrated control system for the safe storage and use of liquid ammonia according to claim 1, characterized in that, The pipeline of the pipeline conveying unit adopts a sealed connection structure, and the shut-off valve is a pneumatic shut-off valve. The walls of the explosion-proof isolation unit are a combination of steel and concrete, and the floor is made of non-sparking concrete.

7. The integrated control system for the safe storage and use of liquid ammonia according to claim 1, characterized in that, The liquid ammonia storage emergency unit also includes a spray system, which is connected to the linkage controller to be activated when the ammonia leak detector detects an ammonia leak.

8. An integrated control method for the safe storage and use of liquid ammonia, characterized in that, The system applicable to claim 1 includes the following steps: The ammonia concentration is monitored in real time using the ammonia leak detector. When the ammonia concentration is detected to reach the preset emergency threshold, the linkage controller automatically controls the lifting support frame to sink the liquid ammonia cylinder into the water pool for submersion and dilution. The exhaust gas purification unit is controlled by the safety interlock control unit to perform exhaust gas purification treatment, including: controlling the heating furnace to heat the ammonia cracking tank to a preset cracking temperature, and then controlling the ammonia-containing tail gas generated during the use of liquid ammonia to be transported into the ammonia cracking tank for catalytic cracking after the preset cracking temperature is reached.

9. The integrated control method for the safe storage and use of liquid ammonia according to claim 8, characterized in that, The system also includes an emergency ventilation fan, and the steps to be performed when the ammonia concentration reaches a preset emergency threshold specifically include: When the ammonia concentration is detected to reach the first-level warning threshold, a first-level response action is executed, including triggering an audible and visual alarm and / or starting the emergency ventilation fan. When the ammonia concentration is detected to reach the secondary alarm threshold, a secondary response action is executed, including controlling the lowering of the lifting support frame, and / or closing the shut-off valve, and / or starting the emergency ventilation fan for ventilation.

10. The integrated control method for the safe storage and use of liquid ammonia according to claim 8 or 9, characterized in that, The preset pyrolysis temperature is 850°C, and the catalyst is a nickel catalyst.

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