As a critical industrial raw material, liquid ammonia requires extreme caution during transportation due to its volatility, flammability, and toxicity. A leak or accident could pose a serious threat to personnel, the environment, and property. Therefore, ensuring the safety of liquid ammonia transportation is crucial. This article details the precautions required when transporting liquid ammonia, helping transporters and businesses better manage and address potential risks.
I. Pre-Transportation Preparations
(Ⅰ) Transport Vehicle Inspection
The vehicle transporting liquid ammonia must be a tanker truck specifically designed for transporting cryogenic liquids. Before transportation, a comprehensive inspection of the vehicle should be conducted to ensure it is in good working order. Inspections include:
Tanker Tightness: Ensure there are no leaks in the tanker's valves, pipes, and joints.
Pressure Gauge and Safety Valve: Check that the pressure gauge is functioning properly and that the safety valve is within its expiration date.
Vehicle Braking System and Tires: Ensure the braking system is reliable, tire pressure is normal, and there is no excessive wear.
Emergency Shutoff Device: Ensure the emergency shutoff device is functioning properly to quickly shut off any liquid ammonia leaks in the event of an accident.
(Ⅱ) Transport Personnel Training
Drivers and escorts transporting liquid ammonia must receive professional training to familiarize themselves with the physical and chemical properties of liquid ammonia and master emergency response procedures. This training should include:
Hazards of Liquid Ammonia: Understand its toxicity, flammability, and volatility.
Operating Procedures: Familiarize themselves with the operating procedures for loading, unloading, and transporting liquid ammonia.
Emergency Response: Master emergency response procedures for liquid ammonia leaks, fires, and other accidents, including the use of fire extinguishers, gas masks, and leak-proofing tools.
Safety Regulations: Understand and comply with national and local laws and regulations regarding the transportation of hazardous chemicals.
(Ⅲ) Documents and Permits
Before transporting liquid ammonia, ensure all necessary documents and permits are in place. This includes:
Dangerous Chemical Transport Permit: Ensure vehicles and personnel have legal transportation qualifications.
Transport Route Approval: Select an appropriate transport route and ensure that the route is approved, avoiding densely populated areas and critical facilities as much as possible.
Emergency Plan: Carry a detailed emergency plan, including leak handling, personnel evacuation, and accident reporting.
II. Precautions During Transportation
(I) Monitoring and Inspection: During transportation, drivers and escorts should regularly check the vehicle's status, especially the pressure gauge and level gauge on the liquid ammonia tanker. If any abnormality is detected, the vehicle should be stopped immediately for inspection and appropriate measures should be taken. For example, if the pressure gauge shows an abnormally high pressure, it may be a liquid ammonia leak or excessive pressure inside the tanker, which requires prompt attention.
(II) Avoiding High Temperatures and Fire Sources: Liquid ammonia easily vaporizes at high temperatures, increasing the internal pressure of the tanker and potentially causing an explosion. Therefore, during transportation, the vehicle should be protected from exposure to high temperatures, such as prolonged periods in direct sunlight. Furthermore, the use of open flames and smoking near the transport vehicle are strictly prohibited to prevent fire or explosion.
(III) Speed Limits: Vehicles transporting liquid ammonia should strictly adhere to traffic regulations, operate within speed limits, and avoid sudden braking and sharp turns. This is because when the liquid ammonia tanker is traveling at high speeds or braking suddenly, the liquid ammonia may slosh inside the tanker, increasing the risk of leakage. Speed limits also help reduce the likelihood of traffic accidents.
(IV) Emergency Preparedness: Transport vehicles should be equipped with necessary emergency equipment, such as fire extinguishers, gas masks, and leak detection and repair tools. Escorts should be familiar with the use of this equipment and be able to take prompt action in the event of an accident. For example, if a liquid ammonia leak is discovered, they should immediately use a gas mask to protect themselves, then use leak detection tools to repair the leak and activate the emergency plan.
III. Precautions During Loading and Unloading
(I) Loading and Unloading Site: Liquid ammonia loading and unloading should be carried out in a dedicated loading and unloading site that is well ventilated and away from sources of fire and heat. Clear warning signs should be posted at the loading and unloading site to restrict access to unauthorized personnel. Firefighting equipment and leak alarms should also be installed at the loading and unloading site to ensure prompt detection and effective action in the event of a leak.
(II) Operating Procedures: When loading and unloading liquid ammonia, operating procedures must be strictly adhered to to ensure the safety of operators. Operators should wear appropriate personal protective equipment, such as gas masks, protective gloves, and protective clothing. Loading and unloading should be carried out slowly to avoid violent shaking and impact from the liquid ammonia. For example, when connecting and disconnecting pipes, ensure that the connections are secure to avoid leaks.
(III) Leak Inspection: After loading and unloading, conduct a comprehensive inspection of the vehicle and loading and unloading equipment to ensure that there are no liquid ammonia leaks. This inspection should include the tightness of pipe connections, valves, and tank trucks. If a leak is detected, immediate measures should be taken to address it and prevent further leakage of the liquid ammonia.
IV. Emergency Response and Accident Reporting
(I) Leak Response: In the event of a liquid ammonia leak, the emergency plan should be immediately activated. Operators should wear gas masks and use specialized plugging tools to seal the leak. Simultaneously, ventilation systems should be activated to dilute the leaked liquid ammonia to prevent accumulation and fire or explosion. A cordon should be established around the leak area to restrict access.
(II) Evacuation: In the event of a liquid ammonia leak or accident, immediate evacuation of nearby personnel should be ensured to ensure personal safety. Evacuation should be directed upwind to avoid inhaling the leaked liquid ammonia. Nearby businesses and residents should also be notified and required to take necessary protective measures.
(Ⅲ) Accident Reporting: After an accident occurs, it should be reported immediately to the local safety regulatory authorities, including information such as the time, location, amount of leakage, and measures taken. Reporting the accident facilitates the timely mobilization of emergency rescue forces and minimizes accident losses.
Transporting liquid ammonia is a high-risk operation and requires special attention to safety. Proper pre-transport preparation, including vehicle inspections, personnel training, and document preparation; strict adherence to transportation precautions, such as monitoring and inspection, avoiding high temperatures and ignition sources, speed limits, and emergency preparedness; and strict adherence to operating procedures and leak checks during loading and unloading, can effectively reduce the risks of liquid ammonia transportation. Furthermore, mastering emergency response methods and promptly reporting accidents can minimize losses in the event of an accident.
