Measurement of drying rate in the production scale dryer

4 MEASUREMENT OF DRYING RATE IN THE PRODUCTION SCALE DRYER 

Numerous drying rate data have been obtained in laboratory drying experiments using thermo-gravimetric analyzers as shown in the previous chapters. However it was difficult to know the actual dr5dng rate or solvent concentration profiles in the pilot or production scale dryer from these experimental results. 

Measured solvent concentration in the supply and exhaust air respectively, at zone k [kg/m ] 

Q wi Volumetric supply and exhaust airflow rale at zone k, respectively m /min] 

The example of solvent concentration measurement and the accompanying results of drying rate calculation are shown in Table 7.3.2., and the accompanying specification of dryer and the formulation of coating solution is given in Table 7.3.3 and 7.3.4. The solvent concentrations at the exhaust duct are measured by gas chromatography(MTl Analytical Instrument 200, Portable GC). The solvent concentrations were measured three times at the same point, and the deviations from flie average value were less flian 5%. 

Wm IVwt Initial and final solvent coating amount respectively (kg/rh and Wait S practically zero in this drying application (less than 1000 ppm) 

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