大型原油储罐防静电流速研究

大型原油储罐往往采用大型油轮进库的方式装卸原油,在满足装卸船时间的要求也必须满足防静电流速的要求.静电的产生与所装卸油品的性质、装卸油管道的长度、管径和流量等因素有关.因此,有必要对它们之间的关系进行研究以保证输油的安全.通过建立以场强和装卸船时间为约束条件的数学模型,在给定初始管径求解满足装卸时间要求的流速,判断是否满足防静电要求,满足则流速可继续增加,直到不满足时输出流速;不满足则按50 mm一档加大管径重新进行循环计算,并给出具体算例进行求解,得出满足100000 m3油罐卸100000 t油轮最小管径为DN400. 同时对理论计算与经验公式进行比较,得出经验公式更适合成品油防静电流速的计算,并不适合原油防静电流速的计算.理论计算误差较小,仅为2.8%.建立的数学模型为原油管道的设计和运行提供理论支持.

Study on Antistatic Flow Speed of Large Crude Oil Storage Tank

Crude oil is often loaded and unloaded into/from large crude oil storage tanks by supertanker entering into the fuel tanks. The requirements of antistatic flow speed must be satisfied in loading and unloading crude oil processes. The generation of static electricity is related to the oil type, length and diameter and flow rate of the oil pipeline. Therefore, it is necessary to study their relations to ensure safe oil transportation. A mathematics model with electric field intensity and loading/unloading oil time as constrained conditions was established. Under given initial diameter, the model was solved to obtain the flow rate meeting the loading/unloading oil time, and whether the obtained flow rate met anti-static requirements or not was analyzed. If the flow rate can satisfy the requirements, the flow rate may be increased until it can not satisfy the requirements; if the flow rate can't satisfy the requirements, the diameter should be increased 50 mm a recycling calculation. A case was solved. The results showed that the minimum diameter was DN400 for unloading crude oil into a 100 000 m3tank from a 100 000 t supertanker. At the same time, the results obtained by theoretical calculation and empirical formula were compared. It's pointed out that the empirical formula is more suitable for calculating the anti-static flow velocity of refined oil, and is not suitable for calculation of anti-static flow velocity of crude oil. Theoretical calculation error is small, only 2.8%. The established mathematical model can provide theoretical support for the design and operation of crude oil pipelines.