Practical solutions for solving bulk solids flow problems

Though well over 100 million tons of Portland cement is consumed in the US each year, many are unaware of the hardships encountered during manufacture of this critical building material. Numerous cement plants are plagued with bulk solids flow problems like bridging, ratholing, and flooding, each of which can negatively impact production efficiency. Some of the most challenging bulk materials are handled in making cement, including limestone, slag, gypsum, bauxite, and clay. Unfortunately the theory of how to design storage and handling equipment for these materials is generally not taught in US universities. Plant operators commonly hammer on hoppers to promote flow, and often this technique is ineffective and creates a safety hazard. This paper will discuss proven and practical technology available to ensure reliable discharge of these cohesive and sticky bulk solids. Hopper flow patterns and flow properties tests will be reviewed, and a brief discussion of interfacing feeders with hoppers is provided.