Safety Operating Procedures for Oil Tanks

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Section 2: Safety Operating Procedures for Oil Tanks 1. For newly built or overhauled oil tanks, an inspection of the tanks must be carried out, and a volume table for the tanks should be prepared. 2. After deciding to start feeding oil, check once again whether all accessories of the oil tank are complete, whether the connections are secure, and whether the valve positions are correct. 3. After thorough inspection, start feeding oil, with the feeding rate to remain within the range permitted by the breather valve. 4. When oil is being poured into the tank, increased patrols and inspections should be carried out to check for any leaks in the welds or at the bottom of the tank. Regular measurements should also be taken. When the oil level approaches the safe level, close monitoring is necessary to prevent accidents such as oil overflow. 5. Based on the specified structure and operational conditions of the oil tanks, it is necessary to clearly define the maximum filling height (safe height) and the minimum level of oil that should remain in each tank. When filling the tanks, it is essential to keep the oil level within the maximum filling height. During pumping, the oil level must not drop below the minimum level. 6. When opening the oil measurement port, the operator should stand upwind to ensure access to fresh air. When measuring the oil level, the measuring tape should be lowered along the aluminum (or copper) guide groove inside the port, to prevent sparks from being generated due to friction between the steel tape and the wall of the port. After taking the measurement, the cover for the oil measurement port should be closed properly, and it is necessary to check whether the washer inside the cover is in good condition. 7. When heating the oil tank, the condensate valve should be opened first, followed by the gradual opening of the air inlet valve, in order to prevent hydraulic shock from damaging the welds of the heating tubes, the gaskets, or other tube fittings. 8. Heating inside the tubes is allowed only when the page is more than 50 centimeters above the heating coil. 9. The oil heating temperature should be 15°C lower than its flash point; if it is necessary to raise the temperature due to system operations, it must not exceed 90°C to prevent bumping accidents caused by water present in the oil. 10. When carrying out dehydration operations on heavy oil tanks, it is advisable to heat the oil temperature to 80°C. When opening the valves, follow the principle of opening them gradually from a small degree to a full opening and then back to a small opening. Operators must stay at their posts carefully to prevent oil leaks. 11. When heating the oil tank, temperature should be measured at regular intervals, and the condensate return water should be checked; if oil is detected in the return water, the cause should be identified promptly. 12. Oil tanks should have the sediment at their bottom removed on a regular basis; the frequency of cleaning can be determined based on the degree of sediment accumulation and the required quality standards, with cleaning generally being carried out every two years or so. 13. Sufficient safety measures must be taken when emptying the tank, and a permit for entering the tank must be obtained. It is not allowed for anyone to enter the tank alone; those who enter must be equipped with a sturdy life-saving signal rope, with the end of the rope remaining outside the tank. There should always be a supervisor near the access holes on the outside of the tank, ready to provide assistance to those inside at any time. 14. When cleaning a tank, after the bottom oil has been drained, steam or hot water is usually used to displace the oil and gas inside the tank. At the same time, manholes as well as ventilation holes are opened to ensure proper air circulation. Operations can only be carried out inside the tank once the gas concentration there is below the explosive limit, and the concentration of oil vapors is below the maximum allowable level, in order to prevent gas explosions or poisoning. 15. After cleaning the oil tank, a thorough inspection of the tank body and all its attachments is necessary, especially to check whether the lower manholes are properly sealed and tightened, and whether the dehydration valves are closed. Only after confirming everything is in order can oil be poured into the tank. 16. Regularly check whether the breathing valve operates smoothly; especially in winter, it is important to ensure that the valve of the breathing valve, as well as the disc of the safety valve and the water accumulated at the bottom of the safety valve, do not freeze. This is to prevent the tank top from bursting or the tank from collapsing due to pressure exceeding acceptable levels during oil filling and drainage operations. The fire suppressors located beneath the breathing valve and safety valve should also be checked regularly to avoid blockages. 17. It is prohibited to enter the tank area wearing synthetic fiber clothing or shoes with nails; it is also forbidden to strike metal objects on the top of the tank, as well as to use flashlights there. 18. Before using a floating roof tank, it is necessary to check the following items: whether the floating ladder is on its track, whether there are any obstructions in the guide frames, whether the sealing devices are functioning properly, whether the manhole at the top is sealed, and whether there is any air trapped in the vent valves. 19. For the first filling of a floating roof tank (or the first filling after it has been emptied), gauging and measurement should be carried out 12 hours after filling the empty tank.