Desiccant dryers are an essential element for any compressed air that comes into contact with food. But where the requirements are less stringent, new technology could be set to offer a desiccant-free, low cost alternative.
A refrigerated dryer chills water vapour to its dewpoint, so it can easily be drained from the system, but it’s not suitable for operations requiring extremely dry air. Nor is it the right option for circuits operating in sub-freezing temperatures.
Desiccant dryers for food manufacturing
Desiccant dryers absorb moisture, so they’re far more effective in freezing conditions and they’re much better at scrubbing the moisture from the air used in food manufacturing systems. If there’s a downside, it’s that they cost a little more initially, they can be energy intensive and the desiccant needs replacing every few years. But those negatives could be set to be removed by a new type of dryer which, once it reaches the UK market, could eliminate the need for desiccant whilst remaining suitable for some food production applications.
The subfreezing dryer isn’t appropriate for all forms of food manufacturing – but it is appropriate for Class 3 applications. As Food Engineering explains, the dryer takes elements from existing dryer technology and combines them.
Drying without desiccant
First is a regenerative dryer with two drying chambers. The first dries the air, while the other regenerates and removes stored moisture. Next, a heat-of-compression (HOC) dryer uses the heat from the compressor to regenerate without wasting any compressed air through purging compressed air. This keeps the dryer highly efficient. Finally, a refrigerated dryer uses refrigerant to dry, which reduces maintenance requirements.
The result is a dryer which should be able to deliver air dried to Class 3 standards, but which will cost less in terms of initial purchase, operation and maintenance.
When the new technology becomes available we’ll let you know. In the meantime, to explore the current new technology that can protect the performance whilst reducing the running costs of your compressed air system, talk to us on 0114 243 2347.