| Supercritical water has very low density and viscosity and dielectric constant. In supercritical water, organics can dissolve with arbitrary proportion, but the solubility of inorganic substance is very low. Based on the special solution properties of organics,the difficult degradable organic wastewater can treatment effectively with supercritical water oxidation technology, But on the other hand, low solubility of inorganic salts in supercritical water make them deposited easily in the reactor. This became the bottleneck of supercritical water oxidation technology's industrial applications. In the industrial application, inorganic deposition is the important content of monitoring and predicting. Therefore, it is necessary to studied the solubility of inorganic salts under different temperature and pressure. Through solubility data, the condition of different processes can be controlled and the situation of salt deposition under different conditions can be forecast.Because the inorganic salt solubility data in supercritical water was deficient,this paper designed a set of experimental apparatus in order to determine the solubility of inorganic salt. Using this device,the solubility of NaCl and Na2SO4 which were easily generated in the process of treating wastewater,was studied through a series of experiments.Through controlling the retention time, temperature and pressure, studied the solubility of two kinds of inorganic salt under different temperature and pressure. Experimental results show that, with the rise of temperature and reduce of pressure, the dissolve balance retention time of two kinds of inorganic salt were gradually shortened, and the solubility were gradually reduced. Namely,in supercritical water conditions, the higher temperature and the smaller pressure lead to the smaller solubility and more deposit.The solubility parameter and density are two important parameters of supercritical water. Based on these two parameters can establish the calculation model of solubility. This paper simulated the solubility parameter and density of supercritical water using Materials Studio4.0.On the basis of simulation data of solubility parameter and density, using experimental datas fitted the calculation model based on solubility parameter and supercritical water density respectively, gotten a series of calculation formula of the solubility under different temperature. By comparing the fitting effect of two kinds of model and experimental data, found that based on solubility parameter calculation model is more outstanding.Through detecting the concentration of Fe2+ on export solution,studied the corrosion of equipment in experimental process, in order to know the corrosion degree of equipment under two kinds of inorganic salt. The result indicated that, the corrosion speed was accelerated with the increment of temperature and pressure, and the corrosion for reactor under Cl- was more serioue than under SO42-. Moreover, the corrosion of reactor can be reduced effectively through desalting before into the reactor.
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