Determination of the optimal construction parameters of dust collection facilities after pneumatic transport installation

Abstract

In metallurgy pneumatic transport installations for powders and metal particles (swarfs, shav- ings, etc.) generated during production processes are widely used. Fine-grained metal waste and/ or intermediate products are characterized by a wide range of particle size composition, different particle shapes and significant differences in the densities of individual components of the disperse system (from 2 to 10 g·cm-3). The listed features of the materials intended for pneumatic transport create certain difficulties in determining the parameters of the disperse system intended for carrying out the transport purposes. The differences in the physical characteristics and properties of the dispersed particles also cause significant differences in their aerodynamic behaviour in the facilities for separating the two phases (solid and gaseous) and for purifying the fluid (most often air) before releasing it into the environment. Unlike dust collection systems for process flue gases, pneumatic conveying systems require initial sedimentation of the transported material and subsequent purification of the transporting fluid (air). The present report summarizes the results of analytical determination of the physical characteristics of waste fine-grained metal materials and calculation of the aerodynamic parameters of dust collection equipment included in the system for the separation of solid-phase particles with sizes greater than 100 μm and subsequent purification of the waste gas to achieve concentration of fine dust particles lower than 5 mg·m-3. Based on the physical parameters of the disperse system, the best available techniques are de- termined for the separation of the solid phase particles and the purification of the waste fluid that is released into the atmosphere, as follow: gravity dust chamber;inertia cylindric cyclone. As a result of calculating the design parameters of the specified dust collection devices, the optimal conditions have been determined for the most complete separation of the transported material from the air flow and the subsequent purification of the air released into the atmosphere to meet the legal limit for emissions of dust particles.