关键词: 储油罐, 呼吸阀, 油罐温度, 油罐压力, 气通量, 峰值守恒法

Abstract: It is one of the requirements to ensure an oil storage tank equipped with breather valves for limiting its vented oil-gas capacity and keeping it in safety. As the variations of physical parameters caused with the time by surroundings of the oil storage tank, the uncertainty of the design of breather valves is increased. There are many physical parameters affecting the gas flow rate through valves. Temperature change is a main factor. Based on temperature variations, a new method, peak mass conversation(PMC), was presented to calculate the gas flow rate through breather valve. The method is referred to the mass change process of both gas phase and liquid phase as an independent mass conservation, taken the gas phase component of the conservation as a research object, and determined its peak gas flow rate under the saturated vapor pressure as the gas flow rate through breathing valve. By applying the principle of mass conservation, the formula for calculating gas flow rate through breather valve was obtained. Compared to the common methods, the PMC is helpful to get actual values as well as improves the accuracy of breather valve design and selection.

Key words: oil storage tank, breather valve, tank temperature, tank pressure, flow rate, peak mass conversation