During the transportation of oil tankers, static electricity acts as an "invisible fire source". Sometimes, if you are not careful, it can cause unexpected and dangerous accidents. So, how to prevent static electricity hazards?
If a tanker truck is filled with too little oil, there will be a large space for shaking during transportation, and static electricity may easily occur; if it is filled with too much oil, it may cause overflow if the oil tank mouth of the tanker truck is not tightly sealed. Therefore, the filling capacity should be around 95%. as appropriate. In addition, driving at a medium speed should be maintained during transportation to ensure that the oil in the tank truck's tank is relatively stable, and emergency braking should be minimized.
The so-called change of oil content refers to the situation where, for example, an oil tank that was originally filled with gasoline is now filled with kerosene or diesel, or vice versa. Changing the oil filling can easily form an explosive mixed gas in the tank, especially when the tank truck tank was originally filled with gasoline and is now filled with kerosene or diesel. The reason is that both kerosene and diesel have the property of absorbing gasoline vapor, which will dilute the oil tank that was originally filled with gasoline vapor and reached a rich state to the point where it can explode. This is especially true in winter. If static electricity occurs Flashover means that serious accidents such as fire and explosion may occur.
According to an accident investigation report by the American Petroleum Institute, of the 620 static electricity accidents that occurred on fuel tanker trailers, 440 were caused by changes in oil filling. Therefore, when changing the oil filling of a tank truck, try to drain the accumulated oil in the tank, open the mouth of the tank, and allow the oil remaining in the tank to evaporate as much as possible. In addition, when loading oil, the oil delivery personnel should also be informed of the original oil contained in the oil tank, so that the oil delivery personnel can operate according to regulations, such as limiting the oil delivery flow rate, etc.
There should be no moisture, impurities, etc. in the tank of a tanker truck, because the water in the fuel will significantly change the charging tendency of the fuel, causing the voltage in the tank to increase dozens or even hundreds of times, and it may also cause sparks in the form of sparks. Discharge.
Impurities in oil also have a great impact on the generation of static electricity, especially some floating substances, such as sawdust, rubber, and isolated metal balls (the floating balls on the tank content gauge of some tank trucks have fallen off), which are very dangerous. The main reason is that this type of conductor has a capacitive effect and can collect and store more electrostatic charges. There is no fixed movement track in the tanker tank, and it is easy to access the tank wall or other accessories in the tanker tank to form an appropriate discharge. gap. According to tests, once this phenomenon is formed, spark discharge may occur as long as the potential difference between the liquid level and the liquid level is 1-2KV (ordinary liquid level is 28-30KV), and the discharge energy is strong, and all the stored energy can be released at one time.
The valves on the oil tank, the exhalation valve, and the sealing ring of the tank cap of the oil tanker truck should always be in good condition to prevent fuel from leaking or overflowing and causing fire due to static electricity flashover.
Before loading and unloading oil, the oil tanker and the oil loading and unloading equipment should be connected together with electrostatic wires (static wires are installed in the oil depot to connect to the tanker).
effect:
① Conduct the static electricity induced by the oil tank to avoid flashover with external substances;
② Keep the oil tanker and the entire oil loading and unloading equipment at the same potential to prevent potential differences;
③ It has the effect of accelerating leakage of electric charges in oil. When connecting the electrostatic wire, be sure to choose a rust-free and exposed metal part of the tanker. Do not connect it to a severely rusted or painted place.
Data show that good electrostatic conductivity can only be achieved when the resistance of the entire electrostatic grounding system is less than 10 ohms. A more ideal approach is to install a special copper connection plate on a certain part of the tank truck for connecting static conductors. In addition, the electrostatic grounding wire on the oil tank truck cannot be used as the electrostatic conductor for loading and unloading oil. The reason is that the tank truck is usually parked on the cement floor or a tight hard ground when loading and unloading oil, and the resistance of the electrostatic grounding wire is not high. It may be lower than 10 ohms. Therefore, it is difficult to ensure that the same potential is maintained with the oil loading and unloading equipment.
The anti-static facilities on oil tankers are mainly static grounding wires and oil separators in the oil tank. There are two types of static grounding wires: chain type and conductive rubber belt. The former has shortcomings such as sparks easily generated by mopping the floor, time lag when grounding, and easy corrosion that increases leakage resistance. Nowadays, newly manufactured tank trucks use rubber grounding straps. Therefore, the electrostatic grounding wire should be adjusted frequently to ensure that it has good contact with the ground. A multimeter should be used to check whether it is smooth and whether there is any breakage. If problems are found, replace them in time. The function of the oil barrier is to reduce the shaking and splashing of oil in the tank during the transportation of the tank truck to reduce the generation of static electricity. If the oil barrier is removed from the maintenance tank, it must be installed in time and must not be considered an optional device.
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