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The Source for Dry Processing and Bulk Handling Technology

Energy Usage – Driver for Development

February 28, 2013

Having been in the bulk materials handling business for almost 30 years it is clear to me that the need for bulk materials handling solutions is as strong as ever. The need to store, feed, convey, discharge, and receive bulk particulate solids in an efficient and environmentally sound manner is growing not diminishing. It is staggering to list all the industries that need to handle particulate solids since almost all forms of manufacturing – even areas one might not think of – need this technology. The scale can vary enormously from (say) a few pounds per hour of carbon black feeding into a flue gas cleaning operations to 10,000 tn/hr of coal into ships at the port of Newcastle in Australia. The range of materials to be handled continues to grow, yet, on the whole, we still do not generally educate undergraduate engineers in this important area.
    In considering what I might address in this guest column, I started to ponder the changes I have seen in the bulk solids handling industry over the last 30 years. Without doubt the biggest change has been the much greater focus on the use of energy. I started out my research career in pneumatic conveying – a technology that has some incredibly strong advantages over alternatives - but is acknowledged as being at the higher end of the specific energy requirements. Back in the 80s, minimized power consumption was not on the list of deliverables. How this has changed. Energy efficiency, and in my part of the world (Australia) minimized water usage, are key targets for any materials handling and processing operation.
    Another big change has been the much greater focus on environmental considerations, particularly dust control and noise pollution. The Bulk Materials Handling Committee of the Institution of Mechanical Engineers in the UK was one of the first professional organizations to recognize the cost to industry in their review in the 1980s. They produced a report entitled “Dust, Mess and Spillage in Bulk Materials Handling Plant – The Cost to UK Industry”, which estimated that in 1987, the cost in the UK alone exceeded 200M pounds sterling. At all levels and sectors of the industry these issues are now well recognized but the challenges of dealing with them are still current.  
    The effect of these changes has altered the approach to the design and implementation of solids handling projects. There is a move to fully enclosed systems and a real focus of specific energy consumed per ton of material conveyed especially so in the heavier end of the industry. For example, there is a push to increase the length of belt conveyors that can be achieved in a single stage to minimize transfers. This has seen a gradual increase in stage length as belt technology has developed and been refined, which has seen stage lengths increase from typically 10 km several years ago to stages in excess of 20km in the last few years. This is a good example of where research effort and the refinement and optimization around a host of conflicting parameters have seen real improvements and developments in belt conveyor technology.
    Similarly, there has been significant research effort in the area of dense-phase pneumatic conveying. The last 30 years has seen an almost cyclical interest in dense-phase pneumatic conveying driven by the need to minimize wear and maintain product quality, but balanced by the more exacting requirements for the design of dense-phase systems in order to ensure reliable operation. However, the drive towards energy efficiency has revitalized the interest in dense-phase pneumatic conveying.
    Hence, there is little doubt that there has been a significant industry shift in terms of the drivers for research and development. Centers such as TUNRA Bulk Solids (TBS) at the University of Newcastle that are highly focused on industry relevant research have seen the shift in its research programs (many of which are collaborative with industry) with a strong focus on reducing energy intensity and minimizing dust and noise pollution. This is clearly important and an indication that the vital industry of bulk materials handling is doing its bit in balancing real industry needs with the global drive for a more efficient use of energy.  
    Professor Mark Jones holds the Chair in Bulk Solids Handling at the University of Newcastle, Australia. He is also the director of the Centre for Bulk Solids and Particulate Technologies and Director of TUNRA Bulk Solids Handling Research Associates. For more information, visit www.bulksolids.com.au/.