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

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 rate of 56000 kg/hr. Particles’ behavior and flow pattern in the dryer affect the cyclones as effective equipment. In evaluation of this system, the numerical simulation of the fluid flow field and particle dynamics, presented by CFD technique, characterize cyclone pressure drop and turbulence parameters. Navier-Stoke equations through the Euelerian-Lagrangian framework by RNG k-ɛ turbulence model are used as mathematical methods and the calculated results are in an acceptable agreement with industrial parameters. The obtained carrier gas flow rates of 14040, 14011 and 14000 m3hr-1 as thermal energy for PE100, BL3, and EX5 respectively cause excellent flow regime, desired final volatile of 0.04%, 0.06% and 0.07% as well as high separation efficiency in different HDPE grades.  The created flow pattern in the dryer makes the efficient use of the immersed coils as another source of energy for drying the particles. Double-cyclones conduct the minimum escaped contents of 70.2, 75.8 and 76.2 for the distributor section and 69.3, 75.3, 75.9 gr in 1 hr for the scrubbing tower. These rates of dusts provide the optimized electrical energy consumptions with maximum saving value of 17%.