Key Technology And Performance Research On Gravity Oil-water Separator

Gravity oil-water separator is the most common oil-water separating equipment used in the process of oil exploitation. As the aging of oilfields, the water content in oilfield produced liquid is increasing, the requirement on the higher efficient oil-water separating equipment is increasing too. Besides, the separator used on the offshore platform will be in a swing state due to the effect of the wind and waves. In this paper, the effect of the factors on the oil-water separating performance are investigated by the means of numerical simulation and experiments, and the effect of the swing is performed by the numerical simulation.The main contents are as follows:A gravity oil-water separator is designed and processed by the reference of the domestic and foreign research. Numerical study on the factors affecting the separating performance of the gravity oil-water separator are performed by CFD software Fluent, the factors include the mixture inlet velocity, oil droplets size, coalescence components, swing frequency and swing amplitude. Then, the experimental research on the separating performance of the gravity oil-water separator prototype is performed on the experimental platform. The effect of the inlet velocity, stirring speed, oil droplets size, and different types of coalescence component on the separating performance are investigated and compared with the results of numerical simulation research. Finally, the efficient separating conditions for this gravity oil-water separator prototype are obtained through the comprehensive study of the numerical simulation and experimental research.According to this paper, the following main conclusions are obtained: The diameter of oil droplets becomes larger when the stirring speed is lower, and different particle size of oil droplets can be obtained by adjusting the stirring speed. The separating effect of gravity oil-water separator is reducing with the increasing of inlet velocity and the decreasing of oil droplets size. Coalescence component can accelerate the collision of oil particle so that the size of oil particle will increase, then it will promote the oil-water separating. Among the four different types of coalescence component, parallel snake plate and parallel corrugated plate can promote the effect of oil-water separation obviously, parallel plate and reversed snake plate can also promote separating but less obviously. The numerical results shows that the gravity oil-water separator can work well when the swing is not strong, but the fierce swing will significantly reduce the oil-water separating efficiency, horizontal and vertical swing will affect more than a single direction of swing, the separating effect is better when the swing cycle is longer, the frequency is lower, the amplitude is smaller. This separator prototype can separate oil-water mixture efficiently when inlet velocity is0.5m/s, stirring speed is 200rpm, and parallel snake plate or parallel corrugated plate is installed in the separator under steady state. The separating effect can be increased by the means of reducing inlet velocity, enlarging oil droplets size, and using coalescence component. Installing anti-shake plate will also weaken the swing and improve the separating efficiency.