Performance Research Of Decanter Centrifuge In The Dewatering Separation Of Coal Ash

As a new and highly efficient dewatering separation equipment, decanter centrifuge has been widely used in many industries, which possessed the advantages of good performance of separation, low water content, running continuously as well as strong processing ability. Considered with the ability of dehydration, decanter centrifuge is one of the most appropriate equipments in dewatering. there is no specific equipment to dewatering and separate coal ash, because of the coal ash characteristics of wide particle diameter distribution, small particle diameter and big throughput. Besides, using the existing decanter centrifuge to dewatering and separate coal ash can cause various problem such as higher water content, small processing capacity and prone to clogging failures. In order to develop new specific equipment to dewatering and separate coal ash or provide basis theory for customers to choose decanter centrifuge, it’s necessary to study and master the decanter centrifuge about the flow field characteristics and the regular of segregation in the process of separating coal ash. This paper made the following aspects:This paper describes the decanter centrifuge’s composition, structural features, working principle and characteristics of the separated material, as well as the physical properties of the coal ash.Based on the flow characteristics of decanter centrifuge drum liquid, theoretical analysis and mechanical model of decanters liquid pook were established between two cases where the screw blade impact, while deriving the equations of motion respectively according to the laminar flow theory.After analyzing and comparing several turbulent model, RNG k-ε is chose as turbulence model. Meshing and setting the boundary conditions of decanter centrifuge by using ICEM software, and importing Fluent software for numerical simulation.Distribution and characteristics of the flow field of the liquid pool in a variety of operating parameters between two cases where the screw blade impact are carried out. And static pressure, dynamic pressure, axial velocity, tangential velocity as well as radial velocity are also studied, by using the discrete phase mode, the motion of coal ash solids is simulated to obtain different size separation, separation time, separation efficiency etc. The result indicates that when absence of screw blade, the axial velocity distribution is more complex and comprehensive tangential velocity is relatively small in the vicinity of the feed inlet which occurs partial reflux. Besides axial velocity was relatively uniform and improve the solid-liquid separation, meanwhile the way of increasing the separation to improve the separation efficiency of fine particles is not appropriate.