ABSTRACT
In general, it is difficult to make online measure-
ment of product quality; it is often an inferred entity
based on experience. The moisture content can be a
measured variable if a suitable moisture sensor is used
in the process. Analyzers are available for moisture
analysis, which can be adapted for automatic, closed-
loop dryer control. The most successful of these units
rely on infrared, microwave, or capacitance detection
[1]. Care must be exercised in the selection to allow
for changes in bulk density or for void spaces, which
will introduce an error. In many industrial-drying
plants, such sensors are not available because either
they are expensive or they have low reliability. Con-
sequently, in such cases the moisture content is an
unmeasured output variable.
