Reduction of alpha lactose monohydrate build-up in pneumatic conveying lines: The use of rubber lined bends

Alpha lactose monohydrate, a normally free flowing powder, has been shown in previous studies to adhere to a surface as a consequence of the physical changes that occur during impact. In a pneumatic conveying process this adhesion can result in a build-up of powder on the conveying line wall, eventually leading to the blocking of the pipeline. These physical changes are thought to occur as a result of the energy released when the lactose crystals undergo attrition. This attrition may be deliberately induced, as is the case with milling or it may be an undesirable effect that occurs as the lactose powder is transported through a pneumatic conveying line. With the previous work already having developed an understanding of the conditions required to cause attrition and adhesion of the powder, this work focused on providing a method that could be used to reduce the attrition, where the need occurs, and to prevent the adhesion and build-up of the powder on the surface. The study has been carried out in two parts; the first looked at the effect of different impact surfaces on attrition. This was carried out on a single particle scale. The results showed that where impact occurred against a rubber surface, attrition was significantly reduced. In the second part of the study a rubber lined bend was placed at a high build-up point in a pneumatic conveying line. The rubber lining proved to be an effective method of reducing build-up at the point in the line.The use of rubber lined surfaces to reduce the breakage and build-up of alpha lactose monohydrate crystals in pneumatic conveying lines was investigated. The study was carried using a single particle approach and in an industrial conveying line. A large reduction in attrition and a complete elimination of build-up was observed.Figure optionsDownload as PowerPoint slide