Numerical simulation on the separation process of liquid-solid two-phase flow in the hydrocyclone separator applicable in geothermal power plant

Most of geothermal power plants experience the deposition problems, mainly silica scaling that exhibits in the brine pipes and/ or the reinjection system. Many techniques have been introduced to overcome this problem, such as hot brine injection system, cold brine injection system and acidizing. Experiences showed that these techniques seemed not to be effective in handling the problems. This study proposes a technique of handling the scaling problem by separation process between liquid and solid using hydrocyclone separator where the solid phase is produced by adding a chemical into the brine. The reaction process between chemical and brine is not considered in this study. Before the manufacturing process, the numerical simulation on the separation process in the hydrocyclone separator is important to be carried out for the guidance in designing the appropriate separator geometry that meets the operating condition. The simulation was carried out using ANSYS Remote Solve Manager (RSM) and Discrete Phase Model (DPM). In this model, the fluid density was assumed to be constant and the inlet pressure was given for boundary condition. The mass flow rate of brines and the particles size were varied to evaluate the effects of these parameters on the cyclone efficiency. The simulation results showed that the values of particle size of 53 µm and the brine mass flow rate of 100 kg/s, respectively give the cyclone efficiency of 86 %. The cyclone efficiency increases as the fluid mass flow rate becomes larger.