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5. Microwave Measuring System, LB 356-456 Micro-Moist
Moisture Content in Coal is an important parameter:
Preparation-Regulate Moisture Content
Handling-Dust-Ice
Transport-Weight
Trading-Weight
Calorific Value 5

6. Microwave Measuring System, LB 356-456 Micro-Moist
Microwave Transmission Techniques are the most accurate
method of determining moisture content of Coal
Attenuation/Area Weight
Phase Shift/Area Weight
Phase Shift and or/Attenuation 6

7. Microwave Measuring System, LB 356-456 Micro-Moist
Attenuation measurement
can provide accuracy up to 1wt% moisture
Temperature dependence error
Bulk Density dependence error
Particle size dependent error
Conductivity dependent error 7

8. Microwave Measuring System, LB 456 Micro-Moist
Phase Shift Measurement:
or (Combined Attenuation and Phase Shift)
Independent of Temperature of Coal
Independent of Particle Size variations
INTEGRAL Area Weight Compensation
Accuracy of 0.2 wt% moisture achievable 8

9. 9 Principle of Operation
Microwave Measuring System, LB Micro-Moist
Principle of Operation 9

10. Microwave Measuring System, LB 354-356-456 Micro-Moist
The choice of GHz frequency range:
Measurement of bulk, not surface. This provides a representative measurement
The temperature coefficient of free water crosses zero at 3 GHz
Attenuation due to ionic conductivity (salt content,…) is reduced at higher
frequencies
Frequency analysis over the frequency range provides phase measurement greater
than 360 deg with plausibility control 10

11. Microwave Measuring System, LB 356 Micro-Moist11

12. Microwave Measuring System, LB 356 Micro-Moist
Coal Preparation Plant: 12

13. Microwave Measuring System, LB 356 Micro-Moist
Coal Preparation Plant management reported precision of 0.4% moisture (one sigma RMS) 13

14. Microwave Measuring System, LB 456 Micro-Moist
Product Improvements:
Reference cable can be replaced by short link if To constant
PT-100 Temperature Compensation with direct connection
Detector to Evaluation Unit uses FSK (Frequency Shift Keying) 14