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PROBLEM 9.7-2 drying tests with a foodstuff
PROBLEM 9.7-2drying tests with a foodstuff
Ercille Mae O PacamoSeptember 9 2014ProblemIn order to test the feasibility of drying a certain foodstuff, drying data were obtained in a tray dryer with air flow over the top exposed surface having an area of 0.186 m2 . The bone-dry sample weight was 3.765 kg dry solid. At equilbrium after a long period, the wet sample weight was 3.955 kg h2o + solid. Hence, 3.955-3.765, or 0.190 kg of equilibrium moisture was present. problemThe following sample weights versus time were obtained in the drying test.
GivenA= 0.186 m2Ws = Ls =3.765 kg dry solidEquilibrium moisture= 0.190 kg h20
REQUIREDcalculate the free moisture content x kg h20/kg dry solid for each data point and plot x versus timeMeasure the slopes, calculate the drying rates R in kg h20/hm2Using this drying rate curve, predict the total time to dry the sample from x=0.20 to x=0.04. use graphical INTERGRATION FOR THE FALLING-RATE PERIOD. WHAT IS THE DRYING RATE RC IN THE CONSTANT-RATE PERIOD AND xC ?Solutiona. calculate the free moisture content x kg h20/kg dry solid for each data point and plot x versus timeSolutiona. calculate the free moisture content x kg h20/kg dry solid for each data point and plot x versus timeTimehrsX kg H20/kg Dry solid
0.00.262680.40.247010.80.226561.40.197612.20.159103.00.119264.20.075965.00.051797.00.017009.00.0061112.00.00000
Solutionb. Measure the slopes, calculate the drying rates R in kg h20/hm2
Solutionb. Measure the slopes, calculate the drying rates R in kg h20/hm2
X kg H20/kg Dry solidR kg H20/h m2
0.2626800.247010.7930110.226561.0349460.197610.9767030.159100.9744620.119261.0080650.075960.7302870.051790.6115590.017000.3521510.006110.1102150.000000.041219
Solutionc. Using this drying rate curve, predict the total time to dry the sample from x=0.20 to x=0.04. use graphical INTERGRATION FOR THE FALLING-RATE PERIOD. WHAT IS THE DRYING RATE RC IN THE CONSTANT-RATE PERIOD AND xC ?
Solutionc. Using this drying rate curve, predict the total time to dry the sample from x=0.20 to x=0.04. use graphical INTERGRATION FOR THE FALLING-RATE PERIOD. WHAT IS THE DRYING RATE RC IN THE CONSTANT-RATE PERIOD AND xC ?
Rc= 0.998 kg H20/ h m2xc= 0.12 kg H20/kg Dry solid
Solutionc. Using this drying rate curve, predict the total time to dry the sample from x=0.20 to x=0.04. use graphical INTERGRATION FOR THE FALLING-RATE PERIOD. WHAT IS THE DRYING RATE RC IN THE CONSTANT-RATE PERIOD AND xC ?
X1/R0.230.9660.201.0240.161.0260.120.9920.081.3690.051.6350.022.840
Solutionc. Using this drying rate curve, predict the total time to dry the sample from x=0.20 to x=0.04. use graphical INTERGRATION FOR THE FALLING-RATE PERIOD. WHAT IS THE DRYING RATE RC IN THE CONSTANT-RATE PERIOD AND xC ?
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