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Join us at Booth 1354!
Bulk Material Flowability Testing – What Is It and Why Does It Matter?
Tracy Holmes and Carrie Hartford
Bulk solids handling systems are often the weakest links in the process plant, and their performance can dictate the performance of the entire operation. Therefore, they deserve special attention. When designing a bin, hopper,
transfer chute, or stockpile for a bulk material, it is critical to understand how the bulk solids will “flow” through the system. Flowability is a function of
the material and the equipment handling it. A “free-flowing” material placed in poorly designed equipment may have difficulty flowing reliably. Similarly, a material that seems difficult to handle placed in the correct equipment may flow without a problem. When designing a liquids plant, the density and viscosity of a liquid is looked up or tested and used as a design parameter. With bulk solids, the design process is similar except the friction, cohesive strength, compressibility and sometimes permeability need to be measured for the material. It is important for these tests to be run at representative process conditions. Measuring flow properties and applying them correctly will reduce project risk and potentially save a significant amount of capital.
Bulk Solids Virtual Simulations vs. Real World Performance
Dr. David Craig and Carrie Hartford
Investigations reveal that the throughput difference between a perfect production day and an average is ~ 40%, and that bulk solids handling (BSH)
system deficiencies are the largest (>50%) class of lost opportunity. To reduce or eliminate BSH problems requires an analysis of troublesome equipment – for example, a transfer chute that experiences plugging, excessive wear, unacceptable dust generation, high belt wear, and product spillage. These problems often lead to significant maintenance costs because of the need to unplug chutes, pick up spillage, or frequently replace wear liners. Further, the process may include a stockpile that only functions at 10% live capacity, or a bin that plugs causing unreliable flow. Simulation tools, such as calibrated Discrete Element Method (DEM) models, can be used to build a virtual model of material flow through the plant such as bins, stockpiles, and transfer chutes. Then changes can be made in these virtual numerical models, such as flowrate and material characteristics (e.g. higher clay/fines/moisture), to evaluate how the changes will respond in reality. Then design or operational changes can be planned for to ensure a successful change.
The 2019 SME Annual Conference & Expo and CMA 121st National Western Mining Conference gives you access to a forum for more than 6,000 industry professionals from across the world to share innovative ideas, best practices and cutting-edge research in more than 120 technical sessions along with an expansive marketplace of more than 575 exhibiting companies.