Question - What Are Some Characteristics Of Bulk Solids That Can Affect Their Ability To Flow Properly?
Answer -
Four (4) main factors to consider include moisture content, temperature, particle size (and shape), and time at rest.
- An increase in moisture content will generally make solids more "sticky". Some solids will absorb moisture from the air, which is why nitrogen is often used as a carrier gas (among other reasons).
- For some solids, their ability to flow can be adversely impacted by temperature or even the length of time that the particles are exposed to a specific temperature. For example, soybean meal flows nicely at 90 °F but start to form large bridges at 100 °F.
- Generally, the finer a bulk solid becomes, the more cohesive the particles. Round particles are generally easier to handle than "stringy" or oddly shaped particles. As particles rest in a bin, they can compact together from their own weight. This can create strong bonds between the particles.
- Often times, re-initiating flow can break these bonds and the solids will flow as normal, but this can depend on the load at given locations in the bin.