The Design Of Inline Deliquidiser And Its Numerical Simulation Research

In recent decades, with the increasing depletion of onshore oil and gas resources, offshore oil and gas is becoming a hot-spots in the field of oil and gas exploration. But technical problems limit its further development, in which gas-liquid separation problem is particularly prominent. The compact inline deliquidiser is getting huge attention and rapid development due to its outstanding features that it can improve the separation efficiency, can solve the problems of the fluid overload of the segregating apparatus and the limited space of the offshore platform and can be used in the oil and gas exploitation in the deep-water area, even the ultra deep-water area. The structural parameters of the inline deliquidiser is presented through numerical simulation and theoretical analysis and its related numerical studies are conducted in this paper. In addition, the experimental methods are employed to verify and analyze the separation performance and the stability of the inline deliquidiser, which lays a foundation for its industrialization.The main research contents are as follows: Closely tracking foreign developments of the inline deliquidiser, on the basis principle of the cyclone separation, the key structural dimensions of the inline deliquidiser are identified preliminary, such as the guide-vane, separation chamber, exhaust pipe and so on. Next, the geometric model of the inner flow field of the inline deliquidiser is built and the distribution of the flow field and the simulation of the separation features in the inline deliquidiser are simulated through the CFD software FLUENT. Following that, it is done further with the different number of the guide-vanes and the guide-vane outlet angles. Then, the laws of separation efficiency and pressure drop loss of the inline deliquidiser caused by the changes of the droplet size, the inlet velocity and the fluid content are achieved. Finally, combining the theory design and the numerical simulation, a set of indoor test system is designed and fabricated. The experimental prototype is tested with the different operating conditions and experiment results obtained are made a contract analysis with the numerical simulation results.According to this paper, the following main conclusions are obtained: the results of the numerical solution show that the separation efficiency of the inline deliquidiser increases with the inlet velocity, the droplet size and guide-vane outlet angle. The pressure drop of the inline deliquidiser increases with the guide-vane outlet angle and inlet velocity, and the pressure drop of the separator increases like a parabolic rise with the inlet velocity, in conformity with the local pressure drop calculation formula. Meanwhile, the coefficient K can be used to represent the energy loss of the inline deliquidiser intuitively and fully during its unit operation process. The number of the guide vane and the guide-vane outlet angle have an optimum value. When the number of the guide vane is eight and guide-vane outlet angle is 45 degrees, the separation efficiency of the inline deliquidiser reaches the best. In certain conditions, fluid content of the inline deliquidiser has also a critical value, any increase or decrease will reduce the separation efficiency of the inline deliquidiser. The experimental results show that when the liquid flow is constant, the separation efficiency and the pressure drop loss of the inline deliquidiser will increase as the gas flow does for the certain structure of deliquidiser. If the gas flow is set, the separation efficiency and the pressure drop loss of the inline deliquidiser will increase first and decrease shortly. Since the experimental results perfectly match the law achieved by simulation analysis, it proves that the numerical simulation method employed in this thesis is reliable.The separation prototype of the inline deliquidiser presents a favorable separation performance and stability during the experimental process.But there is still room for improvement in its separation performance. Moreover, Its research has important practical implications for offshore platforms where space is limited.