Chemical safety instrument control system and control method

Abstract

The invention discloses a chemical safety instrument control system and a control method. The system comprises a reaction kettle monitoring control subsystem arranged for a reaction kettle, an air tank monitoring control subsystem arranged for a compressed air storage tank, a monitoring control subsystem arranged for a pressure pipeline, a sulfuric acid pipeline monitoring control subsystem arranged for a sulfuric acid pipeline, and a sulfuric acid tank area monitoring control subsystem arranged for a sulfuric acid tank area. And the natural gas furnace monitoring control subsystem is arranged for the natural gas furnace. The system is timely in monitoring and rapid in control, and the whole safety system is an independent system, convenient to control and high in safety performance.

Description

Technical Field

[0001] The present invention relates to chemical safety, and in particular to a chemical safety instrument control system and a control method. Background Art

[0002] The chemical industry's production often involves synthesis and reaction processes under high temperature and high pressure environments. The materials used are flammable, explosive, highly corrosive, and toxic, and there are safety risks such as leakage, explosion, toxic gas, and burns. As a result, the incidence of safety accidents in chemical companies is much higher than in other industries.

[0003] In recent years, the implementation of industrial automation has increased productivity, reduced labor intensity, improved working conditions, reduced manual operations, and improved production safety. However, when the production system operates at high load and in harsh environments, the production automation system has a series of problems with the increase in use time, such as aging and interference of transmission lines, malfunction and inaccuracy of execution equipment, damage and reduced accuracy of detection instruments, and line failures. The safety risks are still relatively large, resulting in frequent safety incidents in large chemical enterprises, causing great losses to personnel and property.

[0004] With the support of information technology, chemical companies should establish a safety instrument control system that is suitable for the company's production characteristics. When the production process is at high risk due to abnormalities such as variable exceeding the limit, mechanical equipment failure, malfunction, loss of control, energy interruption, and line aging, the safety instrument control system can automatically complete pre-set actions to ensure that personnel and equipment are transferred to a safe state to the greatest extent possible, thus guarding the last line of defense for safe production. Summary of the Invention

[0005] In order to solve the above-mentioned defects of the prior art, the present invention provides a chemical safety instrument control system and a control method. The present invention has timely monitoring and rapid control. The overall safety system adopts an independent system, which is easy to control and has high safety performance.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: a chemical safety instrument control system, comprising:

[0007] The reactor monitoring and control subsystem established for the reactor includes a reactor temperature sensor, a reactor liquid level sensor, an air cooler, a steam stop valve, and a feed pipeline safety valve. When the reactor temperature sensor detects that the temperature of the reactor has reached a safety limit, an alarm program is initiated. At the same time, the steam stop valve located on the steam inlet pipe to the reactor is controlled to be directly closed to cut off the steam heat supply, and the air cooler is controlled to blow air into the reactor for physical cooling. When the reactor temperature sensor detects that the temperature of the reactor has dropped to a safety recovery value, the steam stop valve is controlled to return to its original state and the air cooler is controlled to stop. When the reactor liquid level sensor detects that the liquid level in the reactor has exceeded a safety limit, an alarm program is initiated. At the same time, the feed pipeline safety valve is controlled to be closed to cut off the feed.

[0008] An air tank monitoring and control subsystem established for a compressed air storage tank includes an air tank pressure sensor and an air tank pressure reducing valve. When the air tank pressure sensor detects that the pressure in the compressed air storage tank reaches a safety set pressure limit, an alarm program is initiated and the air tank pressure reducing valve is controlled to open. When the pressure drops to a recovery value, the air tank pressure reducing valve is controlled to close.

[0009] A monitoring and control subsystem for the pressure pipeline includes a pressure sensor and a shut-off valve. The pressure sensor is used to monitor the pressure of the middle compartment of the double-layer pipeline in the medium- and high-pressure sections. The initial state of the middle compartment is a vacuum. When the pressure sensor detects pressure, it indicates a crack or leak in the pipeline, triggering an alarm sequence and controlling the shut-off valve to close.

[0010] A sulfuric acid pipeline monitoring and control subsystem is established for the sulfuric acid pipeline, including a sulfuric acid pipeline pressure sensor and a sulfuric acid pipeline stop valve. The sulfuric acid pipeline pressure sensors are multiple and are installed in each main, branch, and branch pipe section of the sulfuric acid pipeline. The sulfuric acid pipeline stop valves are multiple and are installed between adjacent sections. When the pressure loss ratio from the main pipe to the branch pipe or from the branch pipe to the branch pipe exceeds the safety limit, indicating a leakage, an alarm program is activated to control the pressure pipeline stop valve at the front end of the section to be closed. The pressure pipeline stop valve can only be opened after maintenance and manual restoration by the duty room staff;

[0011] The sulfuric acid tank area monitoring and control subsystem established for the sulfuric acid tank area includes a tank liquid level gauge, a collection tank liquid level gauge, a tank stop valve, and an atomizer. When the tank liquid level gauge detects that the liquid level in the tank of the sulfuric acid tank area exceeds the safety limit, an alarm program is activated to control the tank stop valve located at the tank inlet to close. When the liquid level in the tank is lower than the safety recovery value, the tank stop valve is controlled to open. When the collection tank liquid level gauge detects that the liquid level in the tank rises to the safety limit, an alarm program is activated to control the atomizer to spray mist water to the vapor cloud area formed by the leaked sulfuric acid for physical cooling.

[0012] A natural gas furnace monitoring and control subsystem established for a natural gas furnace includes a natural gas temperature sensor, a natural gas detector, a natural gas shut-off valve, a cooling water spray valve, a natural gas safety valve, and a blower. The natural gas temperature sensor is established inside the furnace and at the exhaust outlet of the natural gas furnace. When the natural gas temperature sensor detects that the temperature inside the natural gas furnace exceeds a safety limit, an alarm program is initiated to control the opening of the natural gas shut-off valve to be closed by 30%. When the temperature drops to a recovery value, the opening of the natural gas shut-off valve is controlled to be restored to 100%. When the exhaust outlet temperature of the natural gas furnace is detected to exceed a safety limit, an alarm program is initiated to control the cooling water spray valve to be opened and sprayed into the furnace for cooling. The natural gas detector is established in the combustion furnace area of ​​the natural gas furnace. When the natural gas detector detects the presence of combustible gas in the combustion furnace area, an alarm program is initiated to control the natural gas safety valve of the branch pipe of the natural gas pipeline entering the combustion furnace area to be closed, and the blower is controlled to start for exhaust.

[0013] Entering the alarm program means: controlling the alarm of the fire safety duty room system, controlling the alarm of the production site board, the production site board can monitor the numerical values ​​online, and the duty room can directly see the monitoring values ​​displayed on the production site board through video, wherein the monitoring values ​​include the temperature value of the reactor temperature sensor, the liquid level value of the reactor liquid level sensor, the pressure value of the air tank pressure sensor, the pressure value of the pressure pipeline pressure sensor, the pressure value of the sulfuric acid pipeline pressure sensor, the liquid level value of the tank liquid level gauge, the liquid level value of the collection tank liquid level gauge, the temperature value of the natural gas temperature sensor, the temperature value of the natural gas temperature sensor, and the detection value of the natural gas detector.

[0014] The air tank monitoring and control subsystem further includes an air tank temperature sensor, and the temperature inside the air tank monitored by the air tank temperature sensor is used as a reference value.

[0015] All detection elements of the chemical safety instrument control system and the detection elements of the production control system are selected as detection elements of different types of measurement methods, and the accuracy is 1-2 levels higher than the detection elements of the production control system. A single-loop mode is used to feedback and control the safety execution equipment. All execution equipment only has an on / off function or a limit valve switching degree, and does not have an adjustment function; wherein, all the detection elements include the reactor temperature sensor, the reactor liquid level sensor, the air tank pressure sensor, the pressure pipeline pressure sensor, the sulfuric acid pipeline pressure sensor, the tank liquid level gauge, the collection tank liquid level gauge, the natural gas temperature sensor, the natural gas temperature sensor, and the natural gas detector.

[0016] The chemical safety instrument control system is also equipped with a power supply, which adopts a dual power supply mode, one is a conventional power supply line, and the other is a storage power supply, ensuring normal operation for 2 hours after a power outage.

[0017] All valves used in the chemical safety instrument control system are pneumatic valves, and the pneumatic valve storage tank is an independent storage tank. When the air compressor does not produce gas, the gas storage capacity can supply gas to the safety instrument control system; wherein, the valves used include the steam stop valve, the feed pipeline safety valve, the air tank pressure reducing valve, the pressure pipeline stop valve, the sulfuric acid pipeline stop valve, the tank stop valve, the natural gas stop valve, the cooling water spray valve, and the natural gas safety valve.

[0018] All transmission lines of the chemical safety instrument control system use highly shielded signal control lines, and the wire pipes are laid in accordance with fire and explosion protection requirements.

[0019] The chemical safety instrument control system is independent of the production PLC, DCS, and FDS control systems.

[0020] A chemical safety instrument control method comprises the following steps:

[0021] When the reactor temperature sensor detects that the temperature of the reactor has reached a safety limit, an alarm program is entered. At the same time, the steam stop valve on the steam inlet pipe is controlled to be directly closed to cut off the steam heat supply, and the air cooler is controlled to blow air into the reactor for physical cooling. When the reactor temperature sensor detects that the temperature of the reactor has dropped to a safety recovery value, the steam stop valve is controlled to return to its original state and the air cooler is controlled to stop. When the reactor liquid level sensor detects that the liquid level in the reactor has exceeded a safety limit, an alarm program is entered. At the same time, the safety valve of the feed pipeline is controlled to be closed to cut off the feed.

[0022] When the air tank pressure sensor detects that the pressure in the compressed air storage tank reaches the safety set pressure limit, it enters the alarm program and, at the same time, controls the air tank pressure reducing valve to open. When the pressure drops to the recovery value, it controls the air tank pressure reducing valve to close.

[0023] When the pressure sensor of the pressure pipeline detects pressure, it indicates that there is a crack / leakage in the pipeline, and an alarm program is entered to control the shut-off valve of the pressure pipeline to close;

[0024] When the pressure loss ratio from the main pipe to the branch pipe or from the branch pipe to the branch pipe exceeds the safety limit, indicating a leakage, the alarm program is activated to control the shut-off valve of the pressure pipe at the front end of the section to be closed. The shut-off valve of the pressure pipe can only be opened after maintenance and manual restoration by the duty room staff;

[0025] When the tank level gauge detects that the liquid level in the tank of the sulfuric acid tank area exceeds the safety limit, the alarm program is activated to control the tank stop valve located at the tank inlet to close; when the liquid level in the tank is lower than the safety recovery value, the tank stop valve is controlled to open; when the liquid level gauge in the collection tank detects that the liquid level in the tank rises to the safety limit, the alarm program is activated to control the atomizer to spray mist water to the steam cloud area formed by the leaked sulfuric acid for physical cooling;

[0026] A natural gas furnace monitoring and control subsystem established for a natural gas furnace includes a natural gas temperature sensor, a natural gas detector, a natural gas shut-off valve, a cooling water spray valve, a natural gas safety valve, and a blower. The natural gas temperature sensor is set up inside the furnace and at the exhaust outlet of the natural gas furnace. When the natural gas temperature sensor detects that the temperature inside the natural gas furnace exceeds the safety limit, an alarm program is entered to control the opening of the natural gas shut-off valve to be closed by 30%. When the temperature drops to a recovery value, the opening of the natural gas shut-off valve is controlled to be restored to 100%. When the exhaust outlet temperature of the natural gas furnace is detected to exceed the safety limit, an alarm program is entered to control the cooling water spray valve to be opened and sprayed into the furnace for cooling. When the natural gas detector detects that there is combustible gas in the combustion furnace area, an alarm program is entered to control the natural gas safety valve of the branch pipe of the natural gas pipeline entering the combustion furnace area to be closed, and the blower is controlled to start for exhaust.

[0027] In summary, the present invention has achieved the following technical effects:

[0028] The present invention has timely monitoring and rapid control, and the overall safety system adopts an independent system, which is easy to control and has high safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the control block diagram of this system;

[0030] Figure 2This is the device block diagram of this system. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below with reference to the accompanying drawings.

[0032] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0035] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0036] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0037] Example:

[0038] Figure 1 This is the control block diagram of this system. Figure 2 This is the device block diagram of this system, a block diagram of a chemical safety instrument control system, including a reactor monitoring and control subsystem set up for the reactor, an air tank monitoring and control subsystem set up for the compressed air storage tank, a monitoring and control subsystem set up for the pressure pipeline, a sulfuric acid pipeline monitoring and control subsystem set up for the sulfuric acid pipeline, a sulfuric acid tank area monitoring and control subsystem set up for the sulfuric acid tank area, and a natural gas furnace monitoring and control subsystem set up for the natural gas furnace.

[0039] Specifically:

[0040] The reactor monitoring and control subsystem established for the reactor includes a reactor temperature sensor, a reactor liquid level sensor, an air cooler, a steam stop valve, and a feed pipeline safety valve; wherein, when the reactor temperature sensor detects that the temperature of the reactor reaches a safety limit, an alarm program is entered, and at the same time, the steam stop valve located on the steam inlet pipeline is controlled to be directly closed to cut off the steam heat supply, and the air cooler is controlled to blow air into the reactor for physical cooling, and the cooling water valve is opened when necessary; when the reactor temperature sensor detects that the temperature of the reactor drops to a safety recovery value, the steam stop valve is controlled to return to its original state and the air cooler is controlled to stop; when the reactor liquid level sensor detects that the liquid level in the reactor exceeds the safety limit, an alarm program is entered, and at the same time, the feed pipeline safety valve is controlled to be closed to cut off the feed, and the overflowing material can flow to the collection tank through the overflow pipeline;

[0041] An air tank monitoring and control subsystem established for a compressed air storage tank includes an air tank pressure sensor and an air tank pressure reducing valve. When the air tank pressure sensor detects that the pressure in the compressed air storage tank reaches a safety set pressure limit, an alarm program is initiated and the air tank pressure reducing valve is controlled to open. When the pressure drops to a recovery value, the air tank pressure reducing valve is controlled to close.

[0042] A monitoring and control subsystem for the pressure pipeline includes a pressure sensor and a shut-off valve. The pressure sensor is used to monitor the pressure of the middle compartment of the double-layer pipeline in the medium- and high-pressure sections. The initial state of the middle compartment is a vacuum. When the pressure sensor detects pressure, it indicates a crack or leak in the pipeline, triggering an alarm sequence and controlling the shut-off valve to close.

[0043] A sulfuric acid pipeline monitoring and control subsystem is established for the sulfuric acid pipeline, including a sulfuric acid pipeline pressure sensor and a sulfuric acid pipeline stop valve. The sulfuric acid pipeline pressure sensors are multiple and are installed in each main, branch, and branch pipe section of the sulfuric acid pipeline. The sulfuric acid pipeline stop valves are multiple and are installed between adjacent sections. When the pressure loss ratio from the main pipe to the branch pipe or from the branch pipe to the branch pipe exceeds the safety limit, indicating a leakage, an alarm program is activated to control the pressure pipeline stop valve at the front end of the section to be closed. The pressure pipeline stop valve can only be opened after maintenance and manual restoration by the duty room staff;

[0044] The sulfuric acid tank area monitoring and control subsystem established for the sulfuric acid tank area includes a tank liquid level gauge, a collection tank liquid level gauge, a tank stop valve, and an atomizer. When the tank liquid level gauge detects that the liquid level in the tank of the sulfuric acid tank area exceeds the safety limit, an alarm program is activated to control the tank stop valve located at the tank inlet to close. When the liquid level in the tank is lower than the safety recovery value, the tank stop valve is controlled to open. When the collection tank liquid level gauge detects that the liquid level in the tank rises to the safety limit, an alarm program is activated to control the atomizer to spray mist water to the vapor cloud area formed by the leaked sulfuric acid for physical cooling.

[0045] A natural gas furnace monitoring and control subsystem established for a natural gas furnace includes a natural gas temperature sensor, a natural gas detector, a natural gas shut-off valve, a cooling water spray valve, a natural gas safety valve, and a blower. The natural gas temperature sensor is established inside the furnace and at the exhaust outlet of the natural gas furnace. When the natural gas temperature sensor detects that the temperature inside the natural gas furnace exceeds a safety limit, an alarm program is initiated to control the opening of the natural gas shut-off valve to be closed by 30%. When the temperature drops to a recovery value, the opening of the natural gas shut-off valve is controlled to be restored to 100%. When the exhaust outlet temperature of the natural gas furnace is detected to exceed a safety limit, an alarm program is initiated to control the cooling water spray valve to be opened and sprayed into the furnace for cooling. The natural gas detector is established in the combustion furnace area of ​​the natural gas furnace. When the natural gas detector detects the presence of combustible gas in the combustion furnace area, an alarm program is initiated to control the natural gas safety valve of the branch pipe of the natural gas pipeline entering the combustion furnace area to be closed, and the blower is controlled to start for exhaust.

[0046] Among them, entering the alarm program means: controlling the alarm of the fire safety duty room system, controlling the alarm of the production site board, the production site board can monitor the numerical value online, and the duty room can directly see the monitoring value displayed on the production site board through video, wherein the monitoring value includes the temperature value of the reactor temperature sensor, the liquid level value of the reactor liquid level sensor, the pressure value of the air tank pressure sensor, the pressure value of the pressure pipeline pressure sensor, the pressure value of the sulfuric acid pipeline pressure sensor, the liquid level value of the tank liquid level gauge, the liquid level value of the collection tank liquid level gauge, the temperature value of the natural gas temperature sensor, the temperature value of the natural gas temperature sensor, and the detection value of the natural gas detector.

[0047] The air tank monitoring and control subsystem further includes an air tank temperature sensor, and the temperature inside the air tank monitored by the air tank temperature sensor is used as a reference value.

[0048] The present invention sets up temperature and liquid level monitoring points on the reactor, sets the high temperature limit to X degrees and the recovery value to Y degrees according to the equipment characteristics and production safety, and the safe high temperature limit is higher than the high temperature value of the production control system.

[0049] The compressed air storage tank of this invention features pressure and temperature monitoring points, with a pressure limit value X and a recovery value Y set based on equipment characteristics and production safety. The temperature measurement of the compressed air storage tank serves as a reference value, as high temperatures are generally associated with high pressures. The pressure reducing valve and safety valve are used simultaneously, with the pressure limit set higher than the safety valve when the pressure reducing valve is open.

[0050] In the pressure pipeline of the present invention, a double-layer pipeline welding method is adopted for the medium and high pressure sections. The double-layer pipeline method comprises two layers of seamless steel pipes, the inner pipe being made of stainless steel as a transmission pipe, and the outer layer being made of steel pipes that are 1-2 specifications larger than the inner pipe. The internal welding support points (or supports) are spaced to form a hollow state. During installation, the air in the hollow is evacuated to a vacuum state, and a pressure gauge is installed on each branch / section. When pressure appears on the pressure gauge, it means that there may be cracks / leakages in the pipeline, and an alarm state is displayed to remind you to carry out maintenance.

[0051] Pressure monitoring is installed on each branch / section of the sulfuric acid pipeline. When the pressure loss ratio between the main pipe and the branch pipe, or between the branch pipe and the branch pipe is too high (more than 10%-20%), leakage may occur in the pipeline. For pipelines with serious pressure loss, the back-end fire safety duty room system will sound an alarm, and the front-end safety valve (stop valve) of the section will automatically close. It can only be opened manually after maintenance by the duty room personnel.

[0052] In the acid and alkali tank area of ​​the present invention, a liquid level gauge is set on the tank body, and a liquid level gauge is set on the collection tank. When the liquid level gauge detects that the liquefaction in the tank is too high (according to the equipment and production safety setting value), the inlet safety valve is closed. When the liquid level in the tank drops to a safe recovery value, the inlet safety valve is automatically opened; when the liquid level gauge in the collection tank detects that the liquid level in the tank has risen, an alarm is sounded in the fire safety duty room system. The duty room can directly see the real-time situation on the scene through video and send out an alarm signal, and automatically start the safety system. The high-altitude atomizer sprays mist water to physically cool the steam cloud area formed by the leaked sulfuric acid.

[0053] The natural gas furnace of the present invention is provided with temperature detectors in the furnace and at the exhaust port, and safety limit values ​​and recovery values ​​are set according to equipment characteristics and safe production.

[0054] All detection elements of the chemical safety instrument control system and the detection elements of the production control system are selected as detection elements of different types of measurement methods, and the accuracy is 1-2 levels higher than the detection elements of the production control system. A single-loop mode is used to feedback and control the safety execution equipment. All execution equipment only has an on / off function or a limit valve switching degree, and does not have an adjustment function; wherein, all the detection elements include the reactor temperature sensor, the reactor liquid level sensor, the air tank pressure sensor, the pressure pipeline pressure sensor, the sulfuric acid pipeline pressure sensor, the tank liquid level gauge, the collection tank liquid level gauge, the natural gas temperature sensor, the natural gas temperature sensor, and the natural gas detector.

[0055] The chemical safety instrument control system is also equipped with a power supply, which adopts a dual power supply mode, one is a conventional power supply line, and the other is a storage power supply, ensuring normal operation for 2 hours after a power outage.

[0056] All valves used in the chemical safety instrument control system are pneumatic valves, and the pneumatic valve storage tank is an independent storage tank. When the air compressor does not produce gas, the gas storage capacity can supply gas to the safety instrument control system; wherein, the valves used include the steam stop valve, the feed pipeline safety valve, the air tank pressure reducing valve, the pressure pipeline stop valve, the sulfuric acid pipeline stop valve, the tank stop valve, the natural gas stop valve, the cooling water spray valve, and the natural gas safety valve.

[0057] All transmission lines of the chemical safety instrument control system use highly shielded signal control lines, and the wire pipes are laid in accordance with fire and explosion protection requirements.

[0058] The chemical safety instrument control system is independent of the production PLC, DCS, and FDS control systems.

[0059] The present invention monitors the safety instrument control system in high-risk areas (referring to areas with high pressure, high temperature, leakage, and explosion) within chemical enterprises.

[0060] The safety instrument control system adopts a safety system independent of the production PLC, DCS, and FDS control systems to reduce the probability of simultaneous failure of the control function and safety function in the production control system. It can independently complete the safety function of automatic protection interlocking without relying on the process control system. The detection elements, execution elements, communication equipment, and logic operators are all independently set.

[0061] The safety level of the safety instrument control system is higher than the safety level of the production process control. The set limit is above the maximum value of production control and is within the safety hazard range. When such a situation is monitored and detected, the production control system may be out of control. The safety control system intervenes as the last line of defense to stop the dangerous state.

[0062] The transmission lines laid by the safety instrument control system are not related to the transmission lines of the production process control system.

[0063] System Description:

[0064] 1. Set up dangerous production areas, among which the reaction tank area, air compressor area, sulfuric acid tank area, and hot air furnace area are key monitoring areas.

[0065] 2. In the reaction tank area, each reactor is equipped with a thermometer, liquid level gauge, overflow valve, supporting ventilator and cooling water;

[0066] 3. In the air compressor storage tank area, each storage tank shall be equipped with a pressure gauge, a pressure reducing valve, a thermometer, and a dedicated gas storage tank for safety instruments;

[0067] 4. Pressure pipelines are classified by pressure grade. For medium pressure and above pressure pipelines, double-layer seamless steel pipes are used.

[0068] 4. In the sulfuric acid tank area, a liquid level gauge and atomizer are installed on each storage tank;

[0069] 5. The natural gas hot air furnace is equipped with a temperature detector, gas valve, and matching cooling water valve;

[0070] 6. Each workshop is equipped with explosion-proof surveillance cameras and electronic display screens, which can synchronously display the data of the safety detection points in the area and the information on the background display;

[0071] 7. All detection elements of the safety instrument system and the production control system detection elements are selected to use detection elements of different types of measurement methods, and the accuracy is 1-2 grades higher than that of the production control system. A single-loop mode is used to feedback and control the safety actuators. All actuators only have on / off functions (or limit valve switching) and do not have adjustment functions;

[0072] 8. The power supply used by the safety instrument system is a dual power supply mode, one is the conventional power supply line, the other is the energy storage power supply, to ensure that it can operate normally for 2 hours after a power outage.

[0073] 9. All valves used in the safety instrument control system are pneumatic valves. The pneumatic valve storage tank is an independent storage tank. When the air compressor is not producing gas, the gas storage capacity can supply gas to the safety instrument control system.

[0074] 10. All transmission lines of the safety instrument control system use highly shielded signal control lines, and the wire pipes are laid in accordance with fire and explosion prevention requirements.

[0075] 11. All of the above testing equipment is a monitoring system independent of production process control. The main unit is located in the 24-hour fire safety duty room, the main display is located in the fire safety duty room, and the secondary display is located in the production control room. When displays are required at each production site, information is synchronized with the main display. The system utilizes PES technology and can be either a distributed control system or an independent microprocessor. The communication method is HART.

[0076] A chemical safety instrument control method comprises the following steps:

[0077] When the reactor temperature sensor detects that the temperature of the reactor has reached a safety limit, an alarm program is entered. At the same time, the steam stop valve on the steam inlet pipe is controlled to be directly closed to cut off the steam heat supply, and the air cooler is controlled to blow air into the reactor for physical cooling. When the reactor temperature sensor detects that the temperature of the reactor has dropped to a safety recovery value, the steam stop valve is controlled to return to its original state and the air cooler is controlled to stop. When the reactor liquid level sensor detects that the liquid level in the reactor has exceeded a safety limit, an alarm program is entered. At the same time, the safety valve of the feed pipeline is controlled to be closed to cut off the feed.

[0078] When the air tank pressure sensor detects that the pressure in the compressed air storage tank reaches the safety set pressure limit, it enters the alarm program and, at the same time, controls the air tank pressure reducing valve to open. When the pressure drops to the recovery value, it controls the air tank pressure reducing valve to close.

[0079] When the pressure sensor of the pressure pipeline detects pressure, it indicates that there is a crack / leakage in the pipeline, and an alarm program is entered to control the shut-off valve of the pressure pipeline to close;

[0080] When the pressure loss ratio from the main pipe to the branch pipe or from the branch pipe to the branch pipe exceeds the safety limit, indicating a leakage, the alarm program is activated to control the shut-off valve of the pressure pipe at the front end of the section to be closed. The shut-off valve of the pressure pipe can only be opened after maintenance and manual restoration by the duty room staff;

[0081] When the tank level gauge detects that the liquid level in the tank of the sulfuric acid tank area exceeds the safety limit, the alarm program is activated to control the tank stop valve located at the tank inlet to close; when the liquid level in the tank is lower than the safety recovery value, the tank stop valve is controlled to open; when the liquid level gauge in the collection tank detects that the liquid level in the tank rises to the safety limit, the alarm program is activated to control the atomizer to spray mist water to the steam cloud area formed by the leaked sulfuric acid for physical cooling;

[0082] A natural gas furnace monitoring and control subsystem established for a natural gas furnace includes a natural gas temperature sensor, a natural gas detector, a natural gas shut-off valve, a cooling water spray valve, a natural gas safety valve, and a blower. The natural gas temperature sensor is set up inside the furnace and at the exhaust outlet of the natural gas furnace. When the natural gas temperature sensor detects that the temperature inside the natural gas furnace exceeds the safety limit, an alarm program is entered to control the opening of the natural gas shut-off valve to be closed by 30%. When the temperature drops to a recovery value, the opening of the natural gas shut-off valve is controlled to be restored to 100%. When the exhaust outlet temperature of the natural gas furnace is detected to exceed the safety limit, an alarm program is entered to control the cooling water spray valve to be opened and sprayed into the furnace for cooling. When the natural gas detector detects that there is combustible gas in the combustion furnace area, an alarm program is entered to control the natural gas safety valve of the branch pipe of the natural gas pipeline entering the combustion furnace area to be closed, and the blower is controlled to start for exhaust.

[0083] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A chemical safety instrument control system, characterized by: include, The reactor monitoring and control subsystem established for the reactor includes a reactor temperature sensor, a reactor liquid level sensor, an air cooler, a steam stop valve, and a feed pipeline safety valve. When the reactor temperature sensor detects that the temperature of the reactor has reached a safety limit, an alarm program is initiated. At the same time, the steam stop valve located on the steam inlet pipe to the reactor is controlled to be directly closed to cut off the steam heat supply, and the air cooler is controlled to blow air into the reactor for physical cooling. When the reactor temperature sensor detects that the temperature of the reactor has dropped to a safety recovery value, the steam stop valve is controlled to return to its original state and the air cooler is controlled to stop. When the reactor liquid level sensor detects that the liquid level in the reactor has exceeded a safety limit, an alarm program is initiated. At the same time, the feed pipeline safety valve is controlled to be closed to cut off the feed. An air tank monitoring and control subsystem established for a compressed air storage tank includes an air tank pressure sensor and an air tank pressure reducing valve. When the air tank pressure sensor detects that the pressure in the compressed air storage tank reaches a safety set pressure limit, an alarm program is initiated and the air tank pressure reducing valve is controlled to open. When the pressure drops to a recovery value, the air tank pressure reducing valve is controlled to close. A monitoring and control subsystem for the pressure pipeline includes a pressure sensor and a shut-off valve. The pressure sensor is used to monitor the pressure of the middle compartment of the double-layer pipeline in the medium- and high-pressure sections. The initial state of the middle compartment is a vacuum. When the pressure sensor detects pressure, it indicates a crack or leak in the pipeline, triggering an alarm sequence and controlling the shut-off valve to close. A sulfuric acid pipeline monitoring and control subsystem is established for the sulfuric acid pipeline, including a sulfuric acid pipeline pressure sensor and a sulfuric acid pipeline stop valve. The sulfuric acid pipeline pressure sensors are multiple and are installed in each main, branch, and branch pipe section of the sulfuric acid pipeline. The sulfuric acid pipeline stop valves are multiple and are installed between adjacent sections. When the pressure loss ratio from the main pipe to the branch pipe or from the branch pipe to the branch pipe exceeds the safety limit, indicating a leakage, an alarm program is activated to control the pressure pipeline stop valve at the front end of the section to be closed. The pressure pipeline stop valve can only be opened after maintenance and manual restoration by the duty room staff; The sulfuric acid tank area monitoring and control subsystem established for the sulfuric acid tank area includes a tank liquid level gauge, a collection tank liquid level gauge, a tank stop valve, and an atomizer. When the tank liquid level gauge detects that the liquid level in the tank of the sulfuric acid tank area exceeds the safety limit, an alarm program is activated to control the tank stop valve located at the tank inlet to close. When the liquid level in the tank is lower than the safety recovery value, the tank stop valve is controlled to open. When the collection tank liquid level gauge detects that the liquid level in the tank rises to the safety limit, an alarm program is activated to control the atomizer to spray mist water to the vapor cloud area formed by the leaked sulfuric acid for physical cooling. A natural gas furnace monitoring and control subsystem established for a natural gas furnace includes a natural gas temperature sensor, a natural gas detector, a natural gas shut-off valve, a cooling water spray valve, a natural gas safety valve, and a blower. The natural gas temperature sensor is established inside the furnace and at the exhaust outlet of the natural gas furnace. When the natural gas temperature sensor detects that the temperature inside the natural gas furnace exceeds a safety limit, an alarm program is initiated to control the opening of the natural gas shut-off valve to be closed by 30%. When the temperature drops to a recovery value, the opening of the natural gas shut-off valve is controlled to be restored to 100%. When the exhaust outlet temperature of the natural gas furnace is detected to exceed a safety limit, an alarm program is initiated to control the cooling water spray valve to be opened and sprayed into the furnace for cooling. The natural gas detector is established in the combustion furnace area of ​​the natural gas furnace. When the natural gas detector detects the presence of combustible gas in the combustion furnace area, an alarm program is initiated to control the natural gas safety valve of the branch pipe of the natural gas pipeline entering the combustion furnace area to be closed, and the blower is controlled to start for exhaust.

2. A chemical safety instrument control system according to claim 1, characterized in that: The entering the alarm procedure refers to: controlling the alarm of the fire safety duty room system, controlling the alarm of the production site board, the production site board can monitor the numerical value online, and the duty room can directly see the monitoring value displayed on the production site board through video, wherein the monitoring value includes the temperature value of the reactor temperature sensor, the liquid level value of the reactor liquid level sensor, the pressure value of the air tank pressure sensor, the pressure value of the pressure pipeline pressure sensor, the pressure value of the sulfuric acid pipeline pressure sensor, the liquid level value of the tank liquid level gauge, the liquid level value of the collection tank liquid level gauge, the temperature value of the natural gas temperature sensor, the temperature value of the natural gas temperature sensor, and the detection value of the natural gas detector.

3. A chemical safety instrument control system according to claim 1, characterized in that: The air tank monitoring and control subsystem further includes an air tank temperature sensor, and the temperature inside the air tank monitored by the air tank temperature sensor is used as a reference value.

4. A chemical safety instrument control system according to claim 1, characterized in that: All detection elements of the chemical safety instrument control system and the detection elements of the production control system are selected as detection elements of different types of measurement methods, and the accuracy is 1-2 levels higher than the detection elements of the production control system. A single-loop mode is used to feedback and control the safety execution equipment. All execution equipment only has an on / off function or a limit valve switching degree, and does not have an adjustment function; wherein, all detection elements include the reactor temperature sensor, the reactor liquid level sensor, the air tank pressure sensor, the pressure pipeline pressure sensor, the sulfuric acid pipeline pressure sensor, the tank liquid level gauge, the collection tank liquid level gauge, the natural gas temperature sensor, the natural gas temperature sensor, and the natural gas detector.

5. The chemical safety instrument control system according to claim 1, characterized in that: The chemical safety instrument control system is also equipped with a power supply, which adopts a dual power supply mode, one is a conventional power supply line, and the other is an energy storage power supply, to ensure normal operation for 2 hours after a power outage.

6. A chemical safety instrument control system according to claim 1, characterized in that: The valves used in the chemical safety instrument control system are all pneumatic valves, and the pneumatic valve storage tank is an independent storage tank. When the air compressor does not produce gas, the gas storage capacity can supply gas to the safety instrument control system; wherein, the valves used include the steam stop valve, the feed pipeline safety valve, the air tank pressure reducing valve, the pressure pipeline stop valve, the sulfuric acid pipeline stop valve, the tank stop valve, the natural gas stop valve, the cooling water spray valve, and the natural gas safety valve.

7. The chemical safety instrument control system according to claim 1, characterized in that: All transmission lines of the chemical safety instrument control system adopt highly shielded signal control lines, and the wire pipes are laid in accordance with the fire and explosion protection requirements.

8. The chemical safety instrument control system according to claim 1, characterized in that: The chemical safety instrument control system is independent of the production PLC, DCS and FDS control systems.

9. A chemical safety instrument control method, characterized by: A chemical safety instrument control system according to any one of claims 1 to 8 comprises the following steps: When the reactor temperature sensor detects that the temperature of the reactor has reached a safety limit, an alarm program is entered. At the same time, the steam stop valve on the steam inlet pipe is controlled to be directly closed to cut off the steam heat supply, and the air cooler is controlled to blow air into the reactor for physical cooling. When the reactor temperature sensor detects that the temperature of the reactor has dropped to a safety recovery value, the steam stop valve is controlled to return to its original state and the air cooler is controlled to stop. When the reactor liquid level sensor detects that the liquid level in the reactor has exceeded a safety limit, an alarm program is entered. At the same time, the safety valve of the feed pipeline is controlled to be closed to cut off the feed. When the air tank pressure sensor detects that the pressure in the compressed air storage tank reaches the safety set pressure limit, it enters the alarm program and, at the same time, controls the air tank pressure reducing valve to open. When the pressure drops to the recovery value, it controls the air tank pressure reducing valve to close. When the pressure sensor of the pressure pipeline detects pressure, it indicates that there is a crack / leakage in the pipeline, and an alarm program is entered to control the shut-off valve of the pressure pipeline to close; When the pressure loss ratio from the main pipe to the branch pipe or from the branch pipe to the branch pipe exceeds the safety limit, indicating a leakage, the alarm program is activated to control the shut-off valve of the pressure pipe at the front end of the section to be closed. The shut-off valve of the pressure pipe can only be opened after maintenance and manual restoration by the duty room staff; When the tank level gauge detects that the liquid level in the tank of the sulfuric acid tank area exceeds the safety limit, the alarm program is activated to control the tank stop valve located at the tank inlet to close; when the liquid level in the tank is lower than the safety recovery value, the tank stop valve is controlled to open; when the liquid level gauge in the collection tank detects that the liquid level in the tank rises to the safety limit, the alarm program is activated to control the atomizer to spray mist water to the steam cloud area formed by the leaked sulfuric acid for physical cooling; A natural gas furnace monitoring and control subsystem established for a natural gas furnace includes a natural gas temperature sensor, a natural gas detector, a natural gas shut-off valve, a cooling water spray valve, a natural gas safety valve, and a blower. The natural gas temperature sensor is set up inside the furnace and at the exhaust outlet of the natural gas furnace. When the natural gas temperature sensor detects that the temperature inside the natural gas furnace exceeds the safety limit, an alarm program is entered to control the opening of the natural gas shut-off valve to be closed by 30%. When the temperature drops to a recovery value, the opening of the natural gas shut-off valve is controlled to be restored to 100%. When the exhaust outlet temperature of the natural gas furnace is detected to exceed the safety limit, an alarm program is entered to control the cooling water spray valve to be opened and sprayed into the furnace for cooling. When the natural gas detector detects that there is combustible gas in the combustion furnace area, an alarm program is entered to control the natural gas safety valve of the branch pipe of the natural gas pipeline entering the combustion furnace area to be closed, and the blower is controlled to start for exhaust.

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