CFD Study and Energy Optimization of Industrial Double-Cyclone in HDPE Drying Process

In this paper, a double-cyclone is used as a gas-solid separator in the fluid bed-drying process to prepare dry HDPE powder from a wet feed of 56000 kg/hr. The quality of dry HDPE depends mainly on particles behavior and flow pattern in the dryer which affect the double-cyclones as an effective equipment in this process. Controlling of the inlet carrier gas causes excellent flow pattern, desired final volatile and high separation efficiency of different HDPE grades. Less flow rate of escaped particles from the cyclones leads to minimum energy consumption in the used blowers, the distributor orifices without dusts and clean trays in scrubbing tower. Numerical simulation of the fluid flow field and particle dynamics in the double-cyclone presented by CFD technique to characterize cyclone pressure drop and turbulence parameters helps us to evaluate the system. Navier-Stokes equations through the Euelerian-Lagrangian framework by RNG k-ɛ turbulence model are used as a mathematical method. Fluid flow field is solved using the finite volume method based on the PISO pressure-velocity coupling scheme in the fluid computational domain. The CFD calculated results of the cyclone are in an acceptable agreement with industrial operating parameters like pressure drop across the cyclone.