Discussion on the strict prohibition of the inner floating disk from touching the bottom during operation
Thread Content
**Order No. 84 issued by the State Administration of Work Safety stipulates the \"Ten Provisions on Fire and Explosion Prevention in Oil and Gas Tank Farms,\" one of which reads: VI. It is strictly prohibited for the floating disk of internal floating roof storage tanks to touch the bottom while the tank is in operation. Due to the increasing environmental regulations in recent years, many of our tanks have been equipped with internal floating roofs. However, since it is a commercial storage area, there are always customers who request that the internal floating roof tanks be emptied. This was also a common and normal requirement in the past. Because settlement is done after a shipment is completed. However, in accordance with the requirements of Order No. 84, it is also prohibited for the internal floating roof to touch the bottom. How can the requirements be fulfilled while meeting customer needs?
The official explanation is: “The float settling to the bottom occurs when the liquid level in the tank is too low, causing the float to rest on the support legs.” During normal operation, once the floating disk settles at the bottom, a gas space is formed between the disk and the oil surface. When the flow rate of the material is too high, static electricity tends to accumulate at the outlet of the material pipeline, which can easily lead to fires and explosions. ”However, there are times when the containers are empty, and sometimes customers request that a container be sent out with an empty contents level or at a low liquid level. In such situations, how can this be done safely without violating the regulations set by the State Administration of Work Safety?
Additionally, the stainless steel we use features a floating type inner float, with the support feet located on the inner float plate
The space between the floating disk and the material at low liquid levels is inevitable. Not only under the floating disk, but also after it touches the bottom of the tank, the automatic vent valve opens; as a result, the entire interior of the tank is filled with saturated gas from the material. In such situations, static electricity is a major concern, so it’s necessary to reduce the flow rate of liquid in and out to avoid the generation of static electricity. For safety reasons, it’s best to avoid operating at such low liquid levels.
Carry out monitoring and inspection tasks in the strong tank areas and storage areas, check the condition of anti-static facilities to ensure they are in good working order. In particular, it is essential to take proper anti-static measures during the transfer and loading/unloading of materials, as well as under abnormal weather conditions. It is necessary to strictly comply with the relevant provisions of the \"Code for Static Electricity Safety of Liquid Petroleum Products\" (GB13348-2009), control the flow rate of materials, and prevent accidents caused by static electricity. At the same time, when the wind force is above level 5, operators must not carry out related operations ； Operators must not work near the tank during thunderstorm conditions.
We strictly prohibit the level from dropping; basically, the liquid level must not be lower than 2.2 meters. The allocation of oil needs to be determined after careful consideration, with coordination by the dispatch team to assign as many trucks as necessary for the amount of oil available. Generally, there is no need to lower the liquid level. It is only emptied during tank inspection.
After emptying, should the air in the interlayer be removed?