Safety device and alarm method for liquid ammonia tank truck

Abstract

The present invention relates to a safety device and an alarm method for a liquid ammonia tank truck. At present, the emergency shut-off valve of a liquid ammonia tank truck is manually controlled, and personnel are required to track and monitor the entire process of loading and unloading liquid ammonia, exposing personnel to a dangerous environment. A safety device for a liquid ammonia tank truck, comprising: a temperature sensor 1 (1), a temperature sensor 2 (2), a liquid ammonia tank truck valve box (3), a weight sensor (4) and a concentration sensor (5), wherein the temperature sensor 1, the temperature sensor 2, the weight sensor and the concentration sensor are respectively connected to an actuator (12), the temperature sensor 1 is installed at the bottom (outer wall) of the liquid ammonia tank truck (13), and the temperature sensor 2, the weight sensor and the concentration sensor are installed in the valve box of the liquid ammonia tank truck. The present invention is applied to the loading and unloading protection of dangerous goods in the chemical industry and the power industry.

Description

Technical Field

[0001] The invention relates to a safety device and an alarm method for a liquid ammonia tank truck. Background Art

[0002] At present, the emergency shut-off valve of the liquid ammonia tank truck is manually controlled, and personnel are required to track and monitor the entire process of loading and unloading liquid ammonia, and personnel are exposed to dangerous environments. The existing protection device requires manual closing of the discharge valve after the leak is discovered, which is highly uncertain and dangerous. According to relevant data and theoretical calculations, the leakage intensity of pressurized liquid ammonia is large, and it quickly vaporizes and spreads to the surroundings. According to the circumferential leakage calculation of the 5mm flange gap of the DN80 pipeline, the leakage rate is 1.8t / min at 20℃. According to calculations, the lethal concentration radius of 20 tons of liquid ammonia after leakage and diffusion under calm wind conditions is 80m. As ammonia evaporates rapidly and diffuses with the airflow, its impact range can reach nearly 1,000 meters. From the current design of the liquid ammonia denitrification system in thermal power plants, the parts with serious leakage risks are at the discharge interface, as well as the first flange and valve directly connected to the liquid ammonia storage tank. Manual operation has serious lag, and after the leak occurs, the first instinct of the personnel is to escape, and they take safety protection and then isolate, which prolongs the leakage incident and expands the accident. Summary of the invention

[0003] The purpose of the present invention is to provide a safety device and an alarm method for a liquid ammonia tank truck, which effectively improves the safety issues in the process of loading and unloading liquid ammonia. In case of leakage, early warning and cut-off can be carried out in the first time to avoid the expansion of the accident. The leakage situation at the quick connector can be automatically judged and an alarm can be issued. The emergency cut-off valve of the liquid ammonia tank truck can be closed remotely, manually or by remote control, thereby ensuring the safety of loading and unloading.

[0004] The above purpose is achieved through the following technical solutions:

[0005] A safety device for a liquid ammonia tank truck, comprising: a temperature sensor 1, a temperature sensor 2, a valve box of the liquid ammonia tank truck, a weight sensor and a concentration sensor, wherein the temperature sensor 1, the temperature sensor 2, the weight sensor and the concentration sensor are respectively connected to an actuator, the temperature sensor 1 is attached to the bottom (outside) of a storage tank using a magnet, and the micro switches of the temperature sensor 2 and the weight sensor and the concentration sensor are installed in the valve box of the liquid ammonia tank truck.

[0006] The safety device of the liquid ammonia tank truck and the operating device in the valve box of the liquid ammonia tank truck are respectively connected to the liquid phase emergency shut-off valve and the gas phase emergency shut-off valve. The liquid phase emergency shut-off valve and the gas phase emergency shut-off valve are connected to the storage tank through a liquid phase pipeline and a gas phase pipeline.

[0007] The safety device of the liquid ammonia tank truck, the liquid phase pipeline is connected with a dry quick connector, and the liquid phase pipeline is connected with a relief valve.

[0008] The safety device of the liquid ammonia tank truck, the gas phase pipeline is connected with a dry quick connector, and the gas phase pipeline is connected with a relief valve.

[0009] Beneficial effects of the present invention:

[0010] 1. The present invention adds sensors at the bottom of the tank truck and in the valve box to measure the temperature difference at that point, the leakage weight of the tank truck joint, and compare the ammonia concentration with the ambient temperature. When the temperature difference reaches a preset value, the micro switch is actuated to determine that liquid ammonia is leaking and trigger an alarm. When the ammonia concentration reaches the alarm value, the safety device is triggered and sends an action signal to cut off the emergency shut-off valve, thereby achieving safety.

[0011] The invention adds an actuator and a control module on the basis of a spring-type emergency shut-off valve, automatically determines and identifies the leakage of the quick connector of the liquid ammonia tank truck through a micro switch, a temperature and a concentration sensor, realizes the alarm function, and automatically closes the emergency shut-off valve after reaching the protection value, thereby realizing the safety function.

[0012] After the improvement, the present invention realizes remote control of the emergency shut-off valve through a small actuator, and realizes the judgment of leakage by monitoring the temperature and concentration of the liquid phase and gas phase joints of the liquid ammonia tank truck, thereby realizing automatic shut-off of the leakage. An interface is reserved, which can be operated in parallel with the loading and unloading system, and the original safety facilities in the ammonia area can be used to realize the extension function of enlarging the monitoring area and remote control.

[0013] Control part of the present invention:

[0014] Sensor: Use temperature sensor 1 to measure the temperature T1 of the outer wall (bottom) of the storage tank, temperature sensor 2 to measure the temperature T2 inside the valve box of the liquid ammonia tank truck, weight sensor 3 (micro switch) to measure the weight M of the small plate, and concentration sensor 4 to measure the gas concentration C inside and around the valve box.

[0015] Under normal circumstances, T1 measures the tank car temperature, which is slightly lower than the ambient temperature, T2 is the ambient temperature, and the measured value of temperature sensor 2>temperature sensor 1; T1-T2=σ<0; when liquid ammonia leaks, it quickly absorbs heat, and the valve box is in a relatively closed and narrow space. The temperature of T2 drops sharply, causing σ to increase. When σ increases to a predetermined value, it is judged as a suspected liquid ammonia leak A;

[0016] Under normal conditions, there is no liquid in the tray. There is a leakage hole on the tray, and the liquid can be discharged through the leakage hole. The tray automatically resets. When liquid ammonia leaks, the dripping liquid ammonia is collected in the tray. The amount of liquid ammonia entering is greater than the amount of liquid ammonia flowing out through the small hole. Gravity offsets the reverse force generated by the damping spring, triggering the micro switch and generating a weighing alarm B. The B alarm is connected to the control system and triggers a red sound and light alarm at the same time;

[0017] Concentration 4 uses an ammonia concentration detector to measure the leakage concentration C, detect the concentration in a certain area of ​​the docking and unloading system, and expand the detection area;

[0018] Execution part:

[0019] After receiving the system alarm system (1. remote signal; 2. remote control signal; 3. temperature difference & weighing signal; 4. concentration signal), the actuator will act.

[0020] A small cylinder is fixed on the side of the emergency cut-off handle with a quick-release bolt. After the control system issues an execution, the cylinder moves, pushes the emergency cut-off valve to move, closes the valve, and installs a whistle when the cylinder is exhausted. The action process can sound an alarm. The small cylinder uses vehicle-mounted compressed air for air supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Attached Figure 1 It is a structural schematic diagram of the present invention.

[0022] Attached Figure 2 It is a structural diagram of the execution part.

[0023] Attached Figure 3 This is a schematic diagram of the weight sensor structure

[0024] In the figure: 1. temperature sensor 1, 2. temperature sensor 2, 3. valve box of liquid ammonia tank truck, 4. weight sensor, 5. concentration sensor, 6. liquid phase emergency shut-off valve, 7. gas phase emergency shut-off valve, 8. liquid phase pipeline, 9. gas phase pipeline, 10. dry quick connector, 11. relief valve, 12. actuator, 13. storage tank, 14. sewage outlet, 15. alarm, 16. operating device, 17. tray, 18. leakage hole, 19. damping spring, 20. micro switch, 21. base. DETAILED DESCRIPTION

[0025] Embodiment 1:

[0026] A safety device for a liquid ammonia tank truck, comprising: a temperature sensor 1, a temperature sensor 2, a liquid ammonia tank truck valve box 3, a weight sensor 4 and a concentration sensor 5, wherein the temperature sensor 1, the temperature sensor 2, the weight sensor and the concentration sensor are respectively connected to an actuator 12, the temperature sensor 1 is installed in a storage tank 13, and the temperature sensor 2, the weight sensor and the concentration sensor are installed in the liquid ammonia tank truck valve box.

[0027] Embodiment 2:

[0028] According to the safety device of the liquid ammonia tank truck described in Example 1, the operating device 16 in the valve box of the liquid ammonia tank truck is respectively connected to the liquid phase emergency shut-off valve 6 and the gas phase emergency shut-off valve 7, and the liquid phase emergency shut-off valve and the gas phase emergency shut-off valve are connected to the storage tank through the liquid phase pipeline 8 and the gas phase pipeline 9.

[0029] Embodiment 3:

[0030] According to the safety device of the liquid ammonia tank truck described in Example 1 or 2, the liquid phase pipeline is connected to the dry quick connector 10, and the liquid phase pipeline is connected to a relief valve 11.

[0031] Embodiment 4:

[0032] According to the safety device of the liquid ammonia tank truck described in Example 1, 2 or 3, the gas phase pipeline is connected to a dry quick connector, and a relief valve is connected to the gas phase pipeline.

Claims

1. An alarm method for a safety device of a liquid ammonia tank truck, applied to the safety device of a liquid ammonia tank truck, characterized in that: The safety device of the liquid ammonia tank truck includes: a temperature sensor 1, a temperature sensor 2, a weight sensor and a concentration sensor. The temperature sensor 1, the temperature sensor 2, the weight sensor and the concentration sensor are connected to the actuator respectively. The temperature sensor 1 is attached to the outside of the bottom of the storage tank through a magnet. The temperature sensor 2, the weight sensor and the concentration sensor are installed in the valve box of the liquid ammonia tank truck. The alarm method comprises the following steps: (1) Control part: Sensor: Use the temperature sensor 1 to measure the temperature T1 of the outer wall of the storage tank, the temperature sensor 2 to measure the temperature T2 inside the valve box of the liquid ammonia tank truck, the weight sensor to measure the weight M of the pallet, and the concentration sensor to measure the concentration C of the valve box and the surrounding gas; Under normal circumstances, T1 measures the tank car temperature, which is slightly lower than the ambient temperature. T2 is the ambient temperature. The measured value of temperature sensor 2 is greater than the measured value of temperature sensor 1. T1-T2=σ<0. When liquid ammonia leaks, it quickly absorbs heat. The valve box is in a relatively closed and narrow space. The temperature of T2 drops sharply, causing σ to increase. When σ increases to a predetermined value, it is judged as a suspected liquid ammonia leak A. Under normal conditions, there is no liquid in the tray. There are small holes on the tray, and the liquid can be discharged through the small holes to eliminate the deviation caused by condensation of moisture in the air and facilitate the reset of the system; When liquid ammonia leaks, the amount of liquid flowing into the tray is greater than the amount of liquid ammonia flowing out of the small hole, and gravity offsets the reverse force generated by the spring, triggering the weight sensor and generating a weighing alarm B; B alarm is connected to the control part and triggers the red sound and light alarm at the same time; the concentration sensor adopts an ammonia concentration detector, which can measure the leakage concentration and can be conveniently measured in a small space, and the concentration in a certain area of ​​the docking and unloading system can be detected to expand the detection area; (2) Execution part: A small cylinder is fixed on the side of the emergency cut-off handle with a quick-release bolt. After the control system issues an execution, the cylinder moves, pushing the emergency cut-off valve to move and close the valve. A whistle is installed at the cylinder exhaust position, and a sound alarm can be issued during the action process. (3) Logical part When σ increases to a predetermined value, it is judged as a suspected leakage of liquid ammonia A BAfter the weighing alarm is triggered, it is judged that liquid ammonia is suspected to leak B The concentration sensor ammonia concentration detector alarms, judging that liquid ammonia is suspected to leak C A&B signals, C alarm signal and DCS control signal E are sent to the controller at the same time. If any one of the signals is triggered, it means that liquid ammonia is leaking, which triggers the alarm and action actuator to cut off the leakage source.

2. The alarm method of the safety device of the liquid ammonia tank truck according to claim 1 is characterized in that: The operating device in the valve box of the liquid ammonia tank truck is connected to the liquid phase emergency shut-off valve and the gas phase emergency shut-off valve respectively, and the liquid phase emergency shut-off valve and the gas phase emergency shut-off valve are connected to the storage tank through a liquid phase pipeline and a gas phase pipeline.

3. The alarm method of the safety device of the liquid ammonia tank truck according to claim 2 is characterized in that: The liquid phase pipeline is connected to a dry quick connector, and a relief valve is connected to the liquid phase pipeline.

4. The alarm method of the safety device of the liquid ammonia tank truck according to claim 3 is characterized in that: The gas phase pipeline is connected to a dry quick connector, and a relief valve is connected to the gas phase pipeline.

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