Figure 7(a) shows the rate of moisture removal and temperature of Polypropylene for two trials. During 6
hours of dying period temperature of Polypropylene pellets varied between 50-60oC. Temperature of pellets increases
initially then it attains maximum temperature at noon and again it starts falling during late afternoon. This behaviour
of pellet temperature can be explained on the basis of solar intensity and air temperature. During 6 hours of solar
drying, moisture content of 100 g of Polypropylene pellets were reduce from 0.082 to 0.0015% on dry basis. Reduction
in moisture content for Polypropylene is very less as compared to that of Nylon-6. This can be increased if we use
forced convection solar dryer. Drying of Polypropylene falls in the falling rate period, which is clearly shown by
drying rate curve (figure 7 (b)). Trials shows results of drying polypropylene are highly reproducible.