The following companies are full SHAPA members, and with a proven track record in providing high-quality solutions for characterisation, are our recommended suppliers of your requirements for your characterisation equipment. Please click on a name to find out more about the company.
A large number of industries across many sectors including power generation, petrochemical, plastics, bulk and fine chemicals, pigments, pharmaceuticals and agrochemicals, detergents, water treatment, food processing etc, are involved in handling bulk solids in raw ingredient form, either storage of primary ingredients, during intermediate processing or at the packaging and distribution. Many companies supply all of their products in bulk whereas most other manufacturing companies use powders within their process either as an additive or primary ingredient.Consequently, a prodigious variety of bulk solids are stored in hoppers or silos in quantities ranging from a few kilos to hundreds and, in some cases, thousands of tonnes.
It is an unfortunate fact that many installations regardless of their size are plagued by discharge and handling problems. Common difficulties include the inability to discharge on demand through bridging or arching, or difficulties associated with segregation or uncontrollable ‘flushing’. It has long been recognised that these issues result in severe restrictions on plant performance
The main issues for solids processing plants are not necessarily in the chemistry of processes but rather that most problems resulted from the tendency of bulk solids to cause blockages, stick, flow erratically or go where they should not. The lack of a thoughtful design approach to ‘low tech’ items like hoppers is a major factor contributing to production shortcomings
Perhaps the most important aspects for flow are how the product slides on a contact surface e.g. hopper wall, and the resistance offered by the shear strength of the powder. These characteristics are influenced by the ‘condition’ or ‘compaction’ of the bulk – a tightly packed product is less free flowing than a loose aerated powder. This ‘condition’ is directly related to the bulk density.
The actual flow behaviour in a plant is not only contingent on the material characteristics – the equipment form has a major influence too. For example steep hoppers with large outlet sizes often have flow benefits: they prevent arches and rat holes, they generate mass flow and mitigate the effects of segregation. By contrast, a ‘rat hole’ may form if the hopper slope is shallow, so the effective storage capacity of the hopper is reduced. If the outlet is too small, an ‘arch’ may stop the flow altogether.
The following companies are full SHAPA members, and with a proven track record in providing high-quality solutions for characterisation, are our recommended suppliers of your requirements for your characterisation equipment. Please click on a name to find out more about the company
