Environmental Engineering Reference
In-Depth Information
Figure 3.8.
Inray fuel analyzer.
The absorption and scattering of photons are due to the photoelectric effect and Compton
scattering. Figure 3.8 shows an on-line system from the Finnish manufacturer Inray.
3.4.2.5
Method selection
Although a large number of instrumental methods allow for indicative measurement of moisture
content, the actual choice of an instrumental method is likely to depend on several factors. Rather
than recommending a certain technology, the choice depends on the performance of the systems
commercially available. There is also a trade-off between measurement performance and the cost
of a certain system. Further, due to economies of scale a large plant can distribute the cost over
large volumes while a small actor may not afford measurement at all.
A central issue is the type of material to be analyzed and the properties to be determined.
The requirements may range from moisture analysis of a homogeneous material such as sawdust
to determination of several properties of a complex mixture of various types of forest residue.
A special consideration in the Nordic countries is whether the system must be able to analyze
frozen material or not. Further, there are requirements concerning accuracy, precision and the
need for representative sampling. These requirements vary depending on application and are
discussed in more detail in section 3.5.
3.5 PRACTICAL APPLICATIONS FOR MOISTURE DATA
3.5.1
Real-time measurement
During the last decade, several newmethods for non-destructive, real-time moisture measurement
have become commercially available. A number of actual, and potential, applications are listed
in the section below.
3.5.2
Price settlement
Price settlement has been discussed in the section about sampling. Three important requisites
for a reliable method are accuracy, unbiasedness and representative sampling. Price settlement
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