Chemical Technology October 2016

PUMPS AND VALVES

Pumps play a crucial role in the coal preparation process. Tony Lawson, engineering director at Weir Minerals Europe, explains how evolving pump design and condition monitoring are helping drive efficient production at coal mines around the world. Coal, pump design and smart maintenance

T he complexity of a coal preparation plant varies accord- ing to the nature of the rawmaterial, the requirements for the end product and the local regulations around water use and waste production. Some plants can require up to 15 different stages, whilst others have significantly fewer. One thing that many plants have in common is that the coal is moved around the plant by slurry pumps. The pumps are vital components in the process, as the other pieces of equipment in the circuit – screens, hydro cyclones and separators, for example – are all gravity-driven. It is slurry pumps that provide the energy to lift the material to the top of the plant, to transport it from one stage to the next, and to carry waste slurry to the disposal facilities. This crucial role means that the performance of pumps has a direct impact on the efficiency of an operation. A unit that does not perform efficiently can become a major bottleneck in the process. The curved vane centrifugal slurry pump was developed in the middle of the 19th century, and the basic principle remains the same today. However, the increasing sophistica- tion of computational fluid dynamics (CFD) and computer- aided design has seen engineers make significant advances in terms of understanding the complex flow of slurries and how it interacts with the impeller and casing inside a pump. The research that has taken place in recent years has allowed engineers to continue to improve the efficiency,

versatility and ease of repair of pump units and this has meant significant reductions in the total cost of ownership of pumps – the factor that determines the value delivered to the customer. It was this challenge that led the research and develop- ment team at Weir Minerals to develop the latest model of Warman ® slurry pump – the Warman WBH® pump. Over the past 50 years, Weir Minerals’ best selling pump The new Warman MDC pump is designed for heavy-duty slurry applications.

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Chemical Technology • October 2016