Study On Evaporation Loss Of Light Oil Storage Tank

There will be part of the liquid hydrocarbon components vaporized into the air,during the process of oil extraction,refining,storage and transportation,seal,application.Volatile oil and gas into the air would cause a series of consequences,such as the pollution of the environment,the formation of oil and gas gathering,energy consumption.This paper is based on the key research projects of "Development of Control Technology for Volatile Organic Compounds(VOCs)in Petrochemical Enterprises".Collection and processing of the entire technology the row of oil and gas outside the light oil tank is still in the exploratory stage of the status quo.This paper study the concentration of oil and gas produced by the evaporation loss of oil and the change of oil vapor content in exhaled air.Oil evaporation mainly occurs during the process of oil storage.And provide the basis for determining the oil and gas recovery scheme suitable for the actual storage and transportation.The UDF of the tank oil is based on the theory of phase change,and combined with the actual process of oil evaporation loss in the tank.The UDF is written in C language and imported into the FLUENT software to simulate the oil evaporation in the tank.The simulation results show that the evaporation loss of oil is positively correlated with the ambient temperature and wind speed,and it is negatively correlated with the filling rate in the tank.The volatilization rate of different oil is obviously different.The volatilization rate of gasoline is obviously higher than that of diesel oil.The effect of daily temperature change on the exhalation of tank and its oil and gas content was studied.During the temperature rise phase in one day,the temperature of the gas space in the tank is higher than the atmospheric temperature,and the difference between the gas temperature and the ambient temperature is greater when closer to the noon.The maximum temperature difference can be close to 20 K.During this period,there has been gas outside the vent hole.The volume of exhaling gradually increased,and oil vapor concentration gradually increased to 1.3%.As the process of loading and unloading oil tank will produce a lot of oil evaporation loss phenomenon,and thus the process of oil and gas loss to focus on analysis.Aiming at the "wall-hanging phenomenon" of oil in the process of oil production,we can get a series of conclusions.According to the law of evaporation loss of light oil storage tank,the measures to control oil evaporation loss are summarized.According to the wall effect experiment combined with the dynamic grid model,the UDF suitable for evaporation of wall oil is obtained.The UDF of oil adhering to wall and the phase change UDF of the liquid surface evaporation were used to simulate the process of loading and unloading oil.The distribution of oil and gas concentration in the process of loading and unloading oil was obtained.After the oil and oil recovery process,due to the wall effect caused by wall phenomenon,and the existence of oil,oil before the start,there is a certain concentration of oil and gas concentration distribution.When the oil level reaches the maximum allowable liquid level,the tank oil vapor content would reach to 88%.The oil vapor content of the exhaled air in the low flow rate is higher than that of the high flow rate,when the oil is collected at different flow rates and the oil is discharged to the same level.That is,low-speed oil,the oil evaporation loss is greater.Therefore,to avoid the occurrence of electrostatic effects,it is recommended high-speed oil.