Greetings Gunter,

Rather than dehumidification perhaps dilution of plant air is warranted here. Can you increase the ventilation rate into the physical plant to remove plant air more rapidly? Seeing as your processing and packaging is the culprit it seems that increasing air volume into the plant will reduce the total moisture in plant,

preheating intake air will help as well. remember that cold air is heavier than warm air. ■

The question could be better addressed if there was more information about the particular problems that caking is causing. In general, the two main issues raised by caking are sticking to contact surfaces and the forming solid masses. Assuming that the use of anti-caking agents is not effective or satisfactory, the surface adhesion problem can be reduced by: - trace heating to stop condensation, fitting a liner of UHMDP as insulation and for its non-crystall bonding characteristics, or by avoiding extended duration surface contact by inducing regular surface slip, e.g storing in mass flow hoppers and affecting regular small extractions or re-cycling.

Solidification of the bulk has either to be avoided, in the case of silos and storage containers, or accepted and accomodated, as with breaking devices for big bags. To prevent the formation of strong particle bonds in a mass it is necessary to induce regular bulk deformation. This can be done by re-cycling the product, even at relatively small rates if all of the material is regularly sheared. This will not happen within the body of a mass flow hopper and is hopeless in a non-mass flow hopper if the product experiences an extended storage life. However, specially profiled hoppers can be made that does cause a degree of bulk shear to occur with relatively small amounts of flow but a more cost effective method, particularly with existing facilities, is to emloy flow inserts. This is not, however, a techique to be adopted by the amature or faint hearted, but demands considerable expertise and committment.

If the problem is commercially serious it would appear to warrent a technical review by a specialist. Free advice can only go so far. ■