A Study of Drying of Soybean (III)

Some Experiments of Hot Air Drying

Abstract

The drying theory was applied to determine the effects of air temperature and initial moisture content on the drying character of soybean. The data were obtained under the various conditions; air temperatures from 30 to 61.5°C, air velocitiee from 0.6 to 1.7 (m/s), initial moisture contents from 25 to 43 (%) (D. B.), absolute humilities from 0.0055 to 0.0065 (kg H₂O/kg dry air) and grain depth of 3cm.
1) It was found that in the case of remoistened soybean, like other cereals, the results indicated the falling-rate drying equation was applicable to it.
2) The straight lines were obtained, plotting free moisture ratios and drying times on semilogarithmic graph, and the calculated slopes of these lines are related to the drying constant K. This drying constant K has been given by the empirical formura,
K=0.0419 Mo^0.422×e^0.00886t
where Mo=initial moisture content % (D. B.)
t=air temperature °C.
3) Air velocity V has no important bearing on the drying constant, compared with the above-mentioned factors, Mo and t.
4) The pressure drop per grain depth has been given by the empirical formura,
ΔP/L=2.67V^1.37(kg/m²⋅cm).
where ΔP=pressure drop (kg/m²)
L=grain depth (cm)
V=air velocity (m/s).