The effect of particle size and density on pressure gradients in horizontal pipelines in lean phase pneumatic conveying

This project was brought about by the need to improve the accuracy of predicting the pressure losses along pneumatic conveying systems, and in particular, an investigation into the reasons why materials behave differently to each other when conveyed pneumatically along pipelines. It was intended that the information obtained from the project, would improve the accuracy of predicting the pressure losses along pneumatic conveying systems used in industry. A study has shown that no other researcher has investigated the differences between several materials in a systematic approach. This thesis outlines the procedures followed that led to the development of a graph that can be used as an aid for predicting the pressure losses along straight sections of pipeline. Groups of materials that were similar to each other except for the individual particle properties of median particle size or density, were used to find a connection between the properties and the pressure losses. From these comparisons, a fundamental appreciation was obtained, regarding the effect of these particle properties on the characteristic relationships of pressure drop to conveying conditions, and hence an optimum approach to modelling was developed. To obtain test data, the materials were conveyed around a test pipeline at the smaller end of the industrial scale. The pressures were measured along the pipeline to determine the pressure gradients in straight sections, and the pressure drop caused by the bends. Data storage and retrieval systems were used to transfer the data to additional software for analysis. The data was analysed for each material, and then collectively for all the materials, to determine a relationship between the pressure losses and the particle properties. The development of the test rig to meet the objectives of the project, the analysis of the results, and the development of the graph, are explained in detail.