14. Effects of Surface Modifications on Wear Mechanisms in Fly Ash Conveying Pipelines

Pneumatic conveying is a frequently used method of material transport particularly for in-plant transportation over relatively short distances. This is primarily to exploit the degree of flexibility it offers in terms of pipeline routing as well as dust minimization. Approximately 80 % of industrial systems are traditionally dilute phase system which uses relatively large amount of air to stay away from trouble, such as blocking the pipeline. Wear in pneumatic conveying is a very complex problem, and at present, there is limited understanding of the wear mechanisms responsible for the severe wear in certain areas of the pipeline. One of the recent studies [1] showed that the surface modifications by conveying materials can alter surface characteristics which change the wear mechanisms of the pipeline. Better understanding of the surface modifications and their effects on wear mechanisms can play a significant role in developing predictive models for the service life of pneumatic conveying pipelines. In this paper, wear surfaces from fly ash conveying pipeline have been studied for a better understanding of the surface modification and its effects of wear mechanisms. Wear samples were analyzed using SEM Energy Dispersive X-ray Spectroscopy (SEM-EDS). Analysis of surface elements discovered high level of silicon (Si) and aluminum (Al) present in the modified surface areas which apparently responsible for brittle failure of the surface layer. Although the actual form of the chemical compounds has not been analyzed, it is evident that the surface modification by the constituents of the conveying material is one of the major contributors to the severity of wear in fly ash conveying pipelines.