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As a crucial component of the oil transportation system, the oil terminal (or oil tank farm) may often pose some serious threats and damage to the ecological environment and production safety for the oil leakage. An effective emergency management strategy is particularly significant, involving the accurate assessment of leakage time, oil migration path, volume distribution, etc. Therefore, the volume of fluid (VOF) and liquid phase leakage model were applied to investigate the migration and distribution characteristic after the accidental hole occurs in the tank wall, and influence factors including height and diameter of the hole were considered in our study. Results show that the lower the leaking hole position is, the faster the horizontal injection rate of the leakage hole, the increase of the accumulation area of the oil on the ground, and the difference in the overall pressure value at the leakage hole is nearly four times. Under different leakage diameters, the oil spill is symmetrical. The larger the leakage diameter, the higher the amount of oil leakage and the initial leakage speed, the maximum speed is 1.5 times the minimum speed, causing harm to safety and environmental pollution. These results can quickly locate the leakage location of the tank and provide valuable references for emergency management of the oil pipeline transportation system.

Desorption of activated carbon saturated with VOCs (volatile organic compounds) under supercritical CO2 is greatly affected by pressure and temperature, and the influence mechanism remains ambiguous. In this paper, toluene is considered as the representative of VOC, influence of pressure and temperature on the toluene desorption ratio is investigated by experimental and molecular dynamic simulation methods. The experimental results show that the toluene desorption ratio increases as pressure increases, but the influence of temperature on the toluene desorption ratio is affected by pressure. The desorption ratio decreases with increasing temperature at lower pressure, while the desorption ratio increases at the beginning but then decreases with increasing temperature at higher pressure. The mechanism analysis presents that the influence of pressure is governed by “density effect”, the influence of temperature is governed by “density effect” and “diffusion effect” together, the final result is determined by the competition between the two effects.

As the standards for emissions of organic waste gas become increasingly strict, the competitive adsorption of water vapor and organic waste gas is becoming the hot spot of research on treatment of organic waste gas. Therefore, three adsorbents (AdsFOV-1, AdsFOV-2 and AdsFOV-3) were used for the research, and their adsorption capacity and thermal effect were investigated through the static adsorption to the vapors of n-hexane, gasoline and water after structural characterization. In addition, dynamic adsorption experiments were performed with the vapors of n-hexane and gasoline under different relative humidity conditions, so as to study the influence of relative humidity on adsorption effect and temperature rising curve, as well as the stability of cyclic adsorption. Meanwhile, the kinetics behavior of the adsorption process was judged by kinetic fitting. The results show that: the adsorption capacity of the three adsorbents to the vapors of n-hexane and gasoline decreases with the increasing of relative humidity, but the thermal effect of adsorption becomes more obvious. Besides, AdsFOV-1 and AdsFOV-2 have good cyclic adsorption performances, specifically, when the inlet vapor mass concentration is set to 25 g/m3, the outlet vapor mass concentration of the adsorption tower can meet the emission requirements of less than 80 mg/m3. Further, the adsorption kinetics behavior of the three adsorbents on the vapor of n-hexane is consistent with the Bangham dynamic equation, which means the adsorption rate is mainly controlled by the pore diffusion. In general, the research results could provide theoretical basis for the treatment of industrial organic waste gas with high humidity.

Oil evaporation and vapor diffusion from storage tanks will have adverse effects on atmospheric environment, social economy and the safety of tank farm. In this study, the current status and achievement of the researches on oil evaporation and vapor diffusion were summarized in terms of theoretical analysis, experimental research and numerical simulation for tracing carbon emission from storage tanks. Specifically, the potential mechanism of vapor-liquid phase change, mass transfer of oil vapor in the tank gas space, and vapor diffusion were revealed through theoretical analysis. Meanwhile, the field test and wind tunnel experiment were reviewed, which show that most experimental researches are performed in the aspects of temperature variation characteristics of crude oil in tanks, oil vapor emission during vehicle and ship loading, and dynamic structural change of storage tanks. In addition, simulation methods like Direct Numerical Simulation (DNS), Reynolds Average Navier-Stokes (RANS), and Large Eddy Simulation (LES) were used to analyze the vapor-liquid mass transfer, dynamic tracing of oil-gas interface and the process of vapor diffusion and flow under the coupling of different factors, which could trace diffused substances in a wide range with lower costs and shorter time. Finally, based on the low-carbon development demand of oil and gas industry, suggestions and prospects for oil evaporation and vapor diffusion in storage tanks were put forward with the expectation to maximize the comprehensive benefits of environmental protection.

Oil vapor emitted during refueling process has caused serious issues of air pollution, especially the environmental impact in surrounding residential areas. Most petrol stations have installed oil vapor recovery systems, but some stations did not properly maintain or switch on them. With the increasing emphasis on ecological environmental protection, it is more crucial to investigate the internal mechanism of vapor-air mass transfer. In this study, a computational fluid dynamic (CFD) model was developed and verified to analyze the effects of wind speed, vehicles number, and residential layout on oil vapor diffusion in residential areas. Simultaneously, the effectiveness of oil vapor recovery was assessed by comparing contamination before and after recovery. Results indicate that wind speed greatly affects the area and location of excess emission areas (EEAs). As the wind speed increases from 2 m/s to 4 m/s, highest concentration, distance to buildings and width of EEAs decreases by 49.1%, 43.8%, and 33.3%, respectively, and EEAs disappear at the wind speed of 6 m/s. Vehicles number has a more significant effect on the symmetry of EEAs, and EEAs become gradually symmetrical as the number increases from 3 to 12. Further, the enclosure layout proves to be an effective layout for protecting residential air, with a minimum concentration of 0.18 mg/m³ . Notably, the effectiveness of oil vapor recovery is remarkable, with a purification rate of 98.5%. These findings can offer a valuable guidance for controlling air pollution in residential areas and enhancing the environmental protection level of petroleum enterprises. [ABSTRACT FROM AUTHOR]

In order to study the effect of ignition position on the deflagration characteristics of oil mist in ship cabins, a self-constructed simulated cabin experimental platform was created to conduct experiments on the effect of ignition position on oil mist deflagration characteristics. The results indicate that the deflagration process of oil mist under various conditions can be divided into four stages, they are respectively deflagration, turbulent combustion, flame stretch and self-extinguishing. The peak velocity of flame propagation decreases with the increasing of the distance between the ignition position and the nozzle. When the distance increases from 13 cm to 83 cm, the peak velocity decreases by 6 m/s with a reduction of 57.14%. The peak temperature inside the cabin decreases with the increasing of the distance between the ignition position and the nozzle. When the distance increases from 13 cm to 83 cm, the peak temperature decreases by 118.2°C with a reduction of 13.94%. The pressure distribution inside the cabin after ignition increases first and then decreases. As the distance between the ignition position and the nozzle increases, the peak pressure at various positions also increases, and the maximum peak pressure is located at 110 cm in the cabin. At the ignition position of 83 cm, the peak pressure reaches the maximum value of 1.603 MPa, which increases by 0.858 MPa (115.17%) compared with the ignition position of 13 cm. [ABSTRACT FROM AUTHOR]

The pipe structures and opening conditions have an important influence on gas explosion, but little research has been done on the coupling analysis of the two. In order to reveal the effect of pipe structure on the flammability characteristics of hydrogen-air premixed gas under end-opening conditions, the flame structure, flame propagation velocity, explosion pressure and flow field distribution in the explosion process of hydrogen-air premixed gas in different pipe structures were analyzed by numerical simulation. The results show that the flame propagation velocity and pressure are less influenced by the end-opening structure in the initial ignition stage, however, when the flame propagates to the pipe end, the flame propagation velocity in each pipe structure is significantly enhanced. The 90° elbow has a certain inhibitory effect on the flame development, while the T-shaped bifurcation structure can effectively increase the degree of gas detonation. In pipe with large aspect ratio, due to the wall effect, the effect of acoustic oscillation disturbance on the flame front and the air-flow release effect of the end-opening, there are two peaks and two troughs in the pressure rise rate curve of each pipe-line structure. [ABSTRACT FROM AUTHOR]