Research On Dense-Phase Pneumatic Conveying Desulfurated-Gyspum Powder In Complex Pipe Section

Viewing of the growing pressure on the current environment, SO₂ emissions has been a much attention and urgent problem which as the main pollutants of air pollution. Therefore, what the flue gas desulfurate gypsum in thermal power plant is very important and the by-product is desulfurated-gypsum. From the view of quality point, desulfurated-gypsum have high purity, stability composition, high moisture content, smaller particle size, powder shape, containing less water-soluble salts compared with natural gypsum. Therefore there is considerable value in use. But due to the complex terrain from desulfurization tower to the using land, such as gypsum board factory, cement plant, etc. vehicles and transportation costs are too high, which leaded the transports been an application bottleneck.Pneumatic conveying powder is widely used in many kinds of industrial processes because of merits like almost no dust pollution and more flexibility of pipeline layout. Widely used too are the high-density and low-velocity conveying of powder due to merits like the low energy loss, the prevention of the attrition of pipes and that it inhibits to make powder crash. Using dense-phase pneumatic conveying desulfurated-gypsum powder not only can maintain the activity of powder and continuity of easy transportation, but also has important theoretical significance there is an important value and prospects.View of this, variable pipe (including the stepped pipe, diverging pipe) and horizontal curved duct which were widely used in the engineering project and less researched on in the high concentration of fluidized transportation were studied in this paper. In the research we used compress air as the transmission power, desulfurated-gypsum as the transport medium and found out the change and law of flow parameters by changing the geometry of the transmission pipeline, the system's operating parameters and other factors. The experiments indicated that the geometry of the transmission pipeline and the system's operating parameters played an important role. Based on the experiments, the physical and mathematical model was established which considered of the geometry of the transmission pipeline, flow parameters and other factors to calculate the pressure lost. The error analysis shows that the model has good accuracy and can be used to calculate and optimize the pipe layout, providing reference for practical application.Numerical simulation of dense phase pneumatic conveying has been fully developed at the last decade as a new research method. Based on the actual size of the geometry of the transmission pipeline, the geometric model and mesh creation was set up by using the software GAMBIT in former course of treatment. The boundary layer was divided near wall and refinement mesh was carried out in complex pipe in considering of the complexity of the flow to improve the accuracy of the simulation. Based on the experiment, an Euler-Euler two fluid model was used to simulate the process of the pneumatic conveying which was based on the kinetic theory of dense gases and kinetic theory of granular, including the interactions between two phases, particles and the particles, particles and wall in the ANSYS computing Platform. The visual information of flow field in the process such as the distribution of static pressure, dynamic pressure, distribution of particle phase, velocity vectors were simulated and analyzed. The simulation results and experimental results are consistent with each other, indicating that numerical simulation can be used to predict the two-phase flow.