Product recovery solutions for chemicals industry - Chemical & Pharmaceuticals
Efficient recovery of active pharmaceutical ingredients (APIs), chemical substances or food powders after drying applications such as spray and fluid bed drying is frequently a problem. The same problem occurs in many milling and micronization applications. The preferred way to recover these sensitive products is with cyclone collectors due to their direct powder capture. Unlike bag filters or wet scrubbers, cyclones minimize filter or product contamination and product cross contamination and can easily handle a wide range of operating temperature, pressure and moisture conditions.
The current problem with cyclones is their low efficiency. And therefore, when necessary, cyclones have to be complemented with expensive specialized bag filters or wet scrubbers to increase yield or to avoid emissions to the atmosphere.
Client's needsinclude a high cyclone system that dramatically increases powder yield, is easy to clean and is efficient enough to comply with regulatory PM emission limits, thus avoiding the use of secondary filters.
Spray Drying - General Arrangement
Usual spray drying arrangements (single point, two point and closed cycle) include a high efficiency cyclone and a bag filter.
The cyclone serves the purpose of separating and collecting the dried powder originated in the spray-drying chamber. For some chemical powders, the fraction of product escaping to the bag filter is not considered as first grade product, and thus seen as losses. The main reasons for this are contamination with filter fibers, product cross contamination and risk of heat degradation.
For fine powders with a median diameter in volume (MVD) of less than 5 µm, losses due to low cyclone efficiency can rise to more than 25 %.
Fluid Bed Drying - General Arrangement
In fluidized bed arrangements, cyclones are used to recover the fine fraction of the dried powder, collecting or returning it to the bed.
This fraction frequently has a very small particle size distribution which results in low yields in the cyclone.
Improving the efficiency is crucial both to recover first grade product and to reduce filter bag cleaning and frequent change of bags.
Client needs include a cyclone system efficient enough in order to replace the bag filter and comply with regulatory emission limits.