Subtopic: Drying and milling of cereals, pulses and oilseeds
Question Statement:
A batch of $1000\text{ kg}$ of wet paddy at $25\%$ moisture content (wet basis) is dried to $14\%$ moisture content (wet basis). The amount of water removed during drying in $\text{kg}$ is ________ (round off to 1 decimal place).
Answer Key:
127.9
Step-by-Step Solution & Explanation
1. Bone dry matter in initial wet paddy ($W_1 = 1000\text{ kg}$, $M_1 = 25\%$ w.b.):
$DM = W_1 \times (1 - M_1) = 1000 \times (1 - 0.25) = 750\text{ kg}$
2. Dry matter remains constant during drying. Final mass $W_2$ at $M_2 = 14\%$ w.b.:
$DM = W_2 \times (1 - M_2)$
$W_2 = \frac{750}{1 - 0.14} = \frac{750}{0.86} = 872.09\text{ kg}$
3. Mass of water removed $\Delta W$:
$\Delta W = W_1 - W_2 = 1000 - 872.09 = 127.91\text{ kg} \approx 127.9\text{ kg}$