ACHEMA Trendreport Particle Charcterisation A Question of (Particle) Character...
Roughly 50 % or more of substances used in the chemical industry are solids which need to be processed, handled and transported, so it is hardly surprising that exhibitors and visitors at ACHEMA have an interest in bulk solids technology. A learning curve is associated with the handling of powder and granulate.
The ideal particle rarely exists. In most cases, minor variations in size and surface characteristics make it difficult to accurately predict filling and dosing behavior. Knowledge about properties such as bulk solid density, particle size, particle shape, moisture, etc. makes things easier.
Precise characterization of the flow properties is also important. Getting that wrong can lead to disruption in the process flow. Most equipment manufacturers have a test and development center where they can run trials and investigations. The engineering teams identify industry-specific characteristics.
Powder Bulk Handling
The widespread use of pods and capsules for household coffee makers would be inconceivable without particle technology expertise. The same is true of powdered soup and prepared mixes. The trick is to prevent the ingredients from separating after packaging. The dried product has a longer shelf life and is easier to transport than canned soup.
The basic principles behind many bulk solids processing techniques including screening, mixing and comminution have not changed for the past hundred years. That does not mean, however, that no further innovation is possible. Mechanical processing on display in Halls 5 and 6 at ACHEMA is currently undergoing a renaissance.
Bulk solid property profiles are becoming increasingly complex and the quality standards are more and more demanding. Particle size, for example, continues to decrease. 20 years ago the micrometer range tended to be the norm but nanotechnology has now become mainstream. This has created the need for finer distributions.
Strategic Raw Materials
The properties of fluids are now well understood, but surprising things can happen during handling of powder, dust and granulate. This is something which equipment and plant operators are well aware of. What makes bulk solids handling so difficult? One bulk solid can be easily filled, but bridging can be a problem with a second product and a third substance rushes through the pipes like a liquid.
There are products that constantly exhibit different behavior in identical filling trials or, even worse, stagnant zones form in the fourth trial (but not before), negating all of the previous results. Upstream handling of bulk solids can also have an influence. Particle compaction during conveying and filling is a factor that may need to be considered.