Advanced Cyclone Systems, S. A. (ACS) designed a settling chamber, followed by a Hurricane system with the double purpose of dust recovery and Particulate Matter (PM) emission reduction, from a sawdust rotary dryer in an industrial wood pellets production plant with 2 ton/h capacity (VIMASOL).
High quality pellets are manufactured from sawdust coming from nearby sawmilling plants (mainly pine wood), after being dried with VI-MASOL's own drying facility. A furnace burning forestry waste delivers the hot air for the dryer.
Pellets production involves several phases, from the collection of raw material, drying, grinding or milling, granulation and packaging. Learn more about Vimasol Pellets at: http://pellets.vimasol.pt/.
IDENTIFYING THE PROBLEM AND SOLUTION
The existing cyclone after the dryer was not efficient enough to meet the Portuguese emission limit (150 mg/Nms). Measured emissions at the stack reached 1,625 mg/NmJ of total suspended particles (mass flow of 9 kg/h). The objective of the client was to meet the legal standards without investing in a Wet Electrostatic Precipitator (WESP) and contacted ACS to present a solution based on cyclones.
In order to design the most appropriate system for this case, a dust sample was collected through an isokinetic sampling at the stack and subsequently measured in a Coulter LS230 analyzer. With the information of the recovery rate of the existing cyclones and the current emissions of these cyclones, ACS easily perfectly reconstruct the particle size distribution and solids concentration (g/Nm1) at the exit of the dryer.
Hurricane for PM Emission Reduction from Dryer off Gases on a Wood Pellet Production Line 8074 m3/h @ 110 ◦C - Case Study