1. Industries with potential electrostatic hazards: chemical, petroleum, coatings, plastics, pharmaceuticals, food, printing and electronics industries.
2. The cause of static electricity: ①The friction of solid materials in a large area. The solid materials come into contact with each other under pressure and then separate. When the solid materials are extruded and filtered, there will be friction between the pipe wall and the filter wall, and The process of crushing, grinding and mixing solid materials may cause dangerous static electricity accumulation. ②The process of filtering, sieving, pneumatic conveying, mixing, spraying, and transferring of powder materials may also produce dangerous static electricity accumulation. Liquid materials in the process of high-speed flow, filtration, stirring, spraying, spraying, scouring, splashing, pouring, and even sedimentation may cause dangerous static electricity accumulation. ③ Combustible liquid vapor and combustible gas may also cause dangerous static electricity accumulation when they are ejected from gaps or valves at high speeds or flow at high speeds in pipes due to impurities contained in solids or liquids. ④In addition, people wearing synthetic chemical fiber clothing may generate dangerous static electricity accumulation during activities and airplanes in flight. Therefore, many fires and explosions are caused by the accumulation of static electricity.
3. The generation of electrostatic hazards: as we all know, static electricity is caused by the contact, separation or friction of different substances, such as extrusion, cutting, stirring and filtering in the production process, as well as walking, standing up, and undressing in life And so on, will generate static electricity. The most important of these is the contact separation process.
4. Hazards of static electricity: When static electricity accumulates to a certain level, it will be discharged. The sparks of the discharge can induce a mixture of fuel and air, causing explosions and fires. The charge on the charged body is always released. There are two ways to release the charge: natural dissipation and different forms of discharge. Electrostatic discharge is the process of converting electrical energy into heat, which can ignite combustibles and become a source of ignition or explosion.
5. Static electricity can constitute a discharge hazard only when the following conditions are met at the same time:
① The accumulated charge can form an electrostatic voltage that is sufficient to cause sparks;
② There is a suitable discharge gap;
③ The discharge reaches the minimum energy that can ignite combustible gas;
④ The discharge must occur within the explosive concentration range of the explosive mixture. It is generally believed that for places with oil vapor, when there are metal protrusions, it is safe that the potential of the oil surface does not exceed 8-10kV, and the danger is very high when it is close to 20kV. Therefore, the safe oil surface potential value during the storage and transportation of light oil products is specified as 12kV.
6. Regarding the static electricity prevention of oil tanker trucks:
⑴ Reliable electrical connections should be made between the loading and unloading facilities of automobile tank trucks, including crane pipes, oil pipelines, metal oil loading platforms, etc.
And ground.
(2) The ground scales, crane pipes, fueling guns, pipelines, etc. of the oil loading and unloading site should be bridged and equipped with electrostatic grounding devices. The grounding resistance is not more than 100Ω.
⑶ The fuel tank truck fuel delivery site should be equipped with a copper core soft stranded wire with a cross-sectional area of not less than 4mm2, one end of which is connected to a crocodile clamp that can break the paint, a special connecting clamp, etc., so as to connect with the tank truck body; and the other end The grounding device should be connected. ⑷The tank truck should use rubber towed belts, and metal towed belts are prohibited.
⑸ The oil tank of the tanker should be equipped with baffles.
⑹The resistance between the oil tank and the car body shall not be greater than 106Ω. The resistance value of the conductive path between any two points in the metal pipeline or on the conductive parts inside the oil tank and the end of the mopping tape shall not be greater than 5Ω.
⑺ The maximum safe flow rate for crane pipes of different diameters when the tanker is loaded with oil.
⑻The connection between the electrostatic grounding wire and the tank car should meet the following requirements.
① The connection should be tight and reliable, and winding connection is not allowed.
②Connect before opening the tank lid.
③It should be connected to the special ground terminal board of the tanker, etc., and it is not allowed to be connected within 1.5m of the loading and unloading oil port.
④Remove the connection after closing the tank lid.
⑼ During the operation, the light oil products should be loaded and unloaded in strict accordance with the relevant operating procedures.
⑽When the tanker uses the top to fill the oil, the oil loading crane pipe should go deep to the bottom of the tank, and the distance from the bottom of the tank should not be greater than 200mm. Splashing light oil is strictly prohibited.
⑾Original oil tanks with high volatile oil products (including tankers) should be tested for the concentration of oil and gas in the tank when replacing low volatile oil products. When the concentration of oil and gas exceeds 25% of the lower explosive limit, ventilation or cleaning should be carried out.
⑿In the process of loading and unloading flammable fuel products, no field test or test that may generate static ignition sparks is not allowed without approval.
⒀It is strictly forbidden to wipe and test vehicles, objects or the ground in the workplace, and conduct various temporary operations that may cause electrostatic hazards
During oil storage and transportation, whether it is connecting, unloading, blending, storage, transfer, pumping, and transportation, the oil is always in flow and friction. Therefore, every intermediate link in static electricity exists objectively. Sometimes when the conditions are met, a static spark will cause an oil tank, a loading platform, a tank truck or an oil tanker to catch fire and explode instantly.
