The Performance Investigation On Water-Saving Component And Application In Disc Filter Cleaning Process

Titanium dioxide pigment (TiO₂) is a kind of white powder with high opacity, brilliant whiteness, excellent covering power and resistance to color change. These properties have made it a valuable pigment and opacifier for a broad range of applications in paints, plastic goods, inks and paper. During the production procedures of Titanium dioxide pigment, raw materials need washing and cleaning by much water in order to get rid of the impurities. As a fluid machine, ejector is widely applied in industries but few used as water-saving device. In this paper we are engaged in the performance analysis and experimental investigation of the ejector which is used as water-saving component in disc filter cleaning process within TiO₂ production procedures of Xingzhong Titanium Co. in Panzhihua, Sichuan province. By theoretical and experimental research, the main factors governing the performance of water-saving component are determined, and application and economy analysis of water-saving component in disc filter cleaning process are made.The water-saving component is on the basis of ejector theory of fluid dynamics knowledge. When the component works, it is injected with the pressure water as motive fluid and the air from surroundings as suction fluid, then water and air meet with each other and turn out to be gas-liquid two phase flow in the mixing section. While the speed of sound in two phase flow is much lower than it in single phase flow, that is to say that the subsonic flow, including motive fluid and suction fluid, turn out to be the supersonic flow, i.e. the gas-liquid two phase flow; when shock wave occurs, through which pressure of the two phase flow increase abruptly. Accordingly, when water get through the water-saving component, both the flow rate and the velocity of work fluid out of it increase, and the function of it comes into effect.Firstly, we theoretically analyze the performance of water-saving component, which depends on the entrainment ratio of it. The more the value of entrainment ratio of water-saving component is, the greater the effect upon water-saving is. The results show that there are many relations among entrainment ratio, ejector configuration and operating parameters, including area ratio, working pressure, ejecting pressure and outlet pressure. The expressions of parameters are obtained in this paper, and how the variables affecting are also analyzed.Secondly, test-bed of water-saving component is set up, with water as motive fluid and air as suction fluid. According to the theoretical performance analysis of water-saving component, the property parameters of it are studied and the configuration of it is designed. In the experiment investigation, we study that how the water-saving performance of ejector is affected by parameters, viz. the nozzle, the absorber, the mixing-chamber, and the diffuser, and the optimal performance of water-saving component is concluded. According to the optimal performance of water-saving component, the optimal configuration of it is made.Finally, according to the actual TiO₂ production procedures of Xingzhong Titanium Co., the water-saving component is experimentally applied in the disc filter cleaning process, and economy analysis of it in disc filter cleaning process is made.