Fire prevention knowledge for safe transportation

Fire prevention knowledge for safe transportation of liquefied petroleum gas

transportation of liquefied petroleum gas is usually divided into four forms: railway tank car transportation, automobile tank car transportation, automobile loaded steel cylinder transportation and pipeline transportation

I. the danger of transporting liquefied petroleum gas

because liquefied petroleum gas is flammable, explosive and easy to generate static electricity, the process of transporting liquefied petroleum gas is very dangerous

1. there is a fire hazard

the tank car storage tank transporting liquefied petroleum gas is shown in Figure 1. The steel cylinder and gas transmission pipeline often leak gas due to performance loss and failure caused by illegal operation or long-term use and lack of maintenance. The leaked liquefied petroleum gas encounters various ignition sources such as open flames, electrical sparks, electrostatic sparks, sparks emitted from the exhaust funnel of motor vehicles, etc. in the diffusion. Fire hazard

2. There is an explosion risk

under normal temperature, LPG is in a gas-liquid two-phase equilibrium state in the container, and the gas-phase pressure of the container filled according to the regulations can consume more than 980 kPa on one hand. China has a vast territory, and there are certain differences in temperatures across the country; Road traffic is not very developed, and vehicle traffic accidents occur from time to time. Therefore, long-distance liquefied petroleum gas vehicles sometimes suffer from heat, strong vibration and impact, which has the risk of explosion. In addition, the concentration of liquefied petroleum gas leaked from tank cars, steel cylinders and gas transmission pipelines in the air reaches its explosion limit, and there is also a risk of explosion when encountering fire sources

3. Common causes of fire and explosion accidents

(1) illegal operation: illegal operation is not only an important cause of other accidents, but also an important cause of fire and explosion accidents in LPG transportation

(2) traffic accidents: vehicles transporting liquefied petroleum gas often leak liquefied petroleum gas after major traffic accidents, causing explosion and combustion

(3) damage and failure of safety equipment of tank car and gas transmission pipeline: after the damage and failure of safety equipment and accessories of tank car and gas transmission pipeline, there are often two consequences; First, when the tank and gas transmission pipeline rise to the safe pressure relief value, the pressure cannot be safely relieved, resulting in explosion; Second, leakage and emission of gas cause explosion and fire

(4) exhaust gas: tank cars and pipelines transporting liquefied petroleum gas are generally not allowed to exhaust gas. Only in the case of possible explosion, emergency venting is allowed. The liquefied petroleum gas discharged in an emergency will explode and catch fire when it meets the fire source in the diffusion, which is also an important cause of accidents in the transportation of liquefied petroleum gas

(5) heating and explosion of transportation containers: if the steel cylinders of tank cars carrying liquefied petroleum gas are overfilled and exposed to the sun for a long time, sometimes they will leak gas and catch fire; If it is not cooled in time after the fire. Explosions can also occur

II. Fire safety measures

1. Truck tanker transportation

(1) the design and manufacture of LPG truck tanker must comply with the relevant provisions of the state and the labor department. The pressure safety valve, emergency shut-off valve, anti-static grounding chain and other safety accessories of the truck tanker transporting LPG must be complete and meet the safety technical requirements, and should be frequently checked during transportation to maintain sensitivity and reliability. At the same time, In order to prevent fire, explosion-proof electrical devices should be used in the truck tank car transporting liquefied petroleum gas according to the regulations. The tank should be painted with a striking red sign of "no smoking" and the engine exhaust funnel should be equipped with a reliable spark extinguisher. In addition, in order to put out the initial fire in time during transportation, the tanker should also be equipped with two dry powder fire extinguishers of more than 5kg or 1211 fire extinguishers of more than 3kg

(2) the transportation of liquefied petroleum gas by truck tanker must comply with the relevant provisions of the national and local governments on the management and transportation of chemical inflammables, explosives and traffic safety management. Before transportation, carefully check the vehicle condition, hang a striking "dangerous goods" sign in front of the vehicle, and do not tow a trailer, and do not carry other inflammables and explosives. When passing through overpasses, culverts, tunnels and other important highway transportation facilities on the way, pay attention to the elevation, drive at a speed limit, and do not stay; Entering the suburbs of the city, you should drive at the speed limit specified by the local public security organ according to the driving time and driving route, and you are not allowed to pass through important public places and busy markets. The escort must follow the vehicle and must not leave halfway. Smoking is forbidden in the car, and other people are not allowed to ride. Sunshade measures shall be taken for long-distance transportation in summer, and the liquid phase temperature and gas phase pressure of the tank shall be often observed. When the liquid phase temperature reaches 40 ℃, water spraying or splashing outside the tank shall be carried out to cool down. Long distance transportation is not suitable when roads are frozen in winter. Otherwise, wear anti-skid chains on the tires and drive at a limited speed

(3) during transportation, the temporary parking position should be well ventilated and away from organs, schools, bridges, factories, mines, warehouses and densely populated places. A safe distance of more than 25 meters shall be kept from important public buildings and facilities, and a safe distance of more than 40 meters shall be kept from open flames or spark emitting places. When stopping halfway, the driver or escort must stay in the car for supervision, and shall not use open fire or tools that can cause fire for maintenance. During the rest at night, the tank car shall not be parked in the public parking lot, the warehouse of inflammables and explosives, or near ordinary vehicles. Avoid sun exposure when parking in summer

(4) when the liquefied petroleum gas station adopts the truck tanker to transport liquefied petroleum gas, the truck tanker loading and unloading platform must be set in the station. Otherwise, the steam tank nozzle should be led out from the bottle filling room or the compressor room. The fire prevention distance between the truck loading and unloading platform and other buildings shall not be less than 15 meters, and the fire prevention distance between the truck loading and unloading platform and the LPG storage tank shall not be less than 30 meters. A grounding pile with a grounding resistance of not less than 10 Ω * cm shall be set near the loading and unloading platform or nozzle for electrostatic grounding before loading and unloading. In order to ensure that the tank car can be evacuated in time after a fire, fire fighting and disaster relief, the tank car loading and unloading platform or nozzle should be set at least 15 meters in front of it × The 15 meter return yard is equipped with two dry powder fire extinguishers of more than 8 kg

(6) before loading and unloading, the tank car should stop and shut down, connect the ground wire, firmly connect the pipe interface, and exhaust the internal air. During loading and unloading operations, it is not allowed to start the vehicle, drain the liquid and deflate, and it is not allowed to use ignition tools. In case of thunderstorm, abnormal hydraulic pressure, nearby fire, and other factors threatening the safety of loading and unloading, the truck tanker shall stop loading and unloading operations. When the truck tanker is filling LPG, it shall be carefully measured and shall not be overloaded. After arriving at the station, the tank car carrying liquefied petroleum gas should be allowed to stand for 30 minutes, and then the liquid should be discharged in time. The tank car should not be used as a temporary storage tank, and the steel cylinder should not be inflated directly from the tank car. After the tank car is unloaded, the residual pressure of more than 49 kPa shall be left in the tank to avoid the explosion hazard caused by air entering the tank

(7) after unloading, the tank car should be parked in the special tank garage, and should not be parked in other places at will. The tank car garage should be grade I and II fire-resistant buildings, and the fire separation between the tank car garage and civil buildings should not be less than 30 meters, and the fire separation between the tank car garage and plant and warehouse should not be less than 12 meters. The warehouse shall be well ventilated, and the lighting and other electrical equipment shall meet the explosion-proof requirements, and shall be equipped with more than 2 8 kg dry powder fire extinguishers. It is forbidden to set basements and trenches in the warehouse, repair vehicles, and store other inflammable and explosive materials

2. Railway tank car transportation

(1) the design, manufacture, use, maintenance and operation of LPG railway tank car shall comply with the relevant regulations of the state and labor, railway, chemical and other departments. The tank shall be painted with a striking red sign of "no smoking" and equipped with necessary fire-fighting equipment at appropriate positions

(2) before filling LPG in LPG railway tank car, carefully check the condition of safety accessories such as pressure, liquid level and emergency cut-off device, and check the name of filling medium in the tank car. It is forbidden to fill those with incomplete safety accessories or poor performance, and the railway tank car carrying liquefied gases such as liquid chlorine shall not carry liquefied petroleum gas. When loading and unloading liquefied petroleum gas, the tank car shall strictly implement the safety operation procedures to prevent liquid leakage and gas leakage, so as to avoid the accumulation of liquefied petroleum gas in the loading and unloading site and the formation of fire hazards. In case of thunderstorm, abnormal tank hydraulic pressure, gas leakage, fire near the loading and unloading site and other factors that threaten the safety of loading and unloading, the loading and unloading operation shall be stopped. Liquefied petroleum gas stations use railway tank cars to transport liquefied petroleum gas. A railway tank car loading and unloading trestle should be set up in the production area of the station. The center line of the loading and unloading parking line is away from the pressure sensor of the liquefied petroleum gas storage tank. After the output signal passes through two inverse closed-loop amplifiers, the output voltage signal meets the requirements of single-chip microcomputer collection. The fire separation distance should not be less than 20 meters, Only when some people saw the exhibition did they know that there were 3D printing technology tanks 30 meters away from the dedicated line. The sign of "locomotive parking position" should be set with the consent of the relevant railway bureau. Fireworks are strictly prohibited within 30 meters of the loading and unloading site. In order to put out the initial fire that may occur during the loading and unloading operation in time, the loading and unloading trestle should be equipped with one 8kg dry powder extinguisher every 10-15 meters in length, and the whole loading and unloading trestle should be equipped with at least two extinguishers