Question

The quantity of water needed to increase the moisture content of 50 kg paddy grains from 13% (dry basis) to 35% (dry basis) in the hydrothermal treatment process is _________ kg. (Rounded off to 2 decimal places)

Hint:

To calculate the quantity of water needed for moisture content change, use the initial mass of the paddy and the difference in moisture content, considering the final and equilibrium moisture content values.

Answer 1

Given: Initial moisture content (dry basis): $X_1 = 0.13$ Final moisture content (dry basis): $X_2 = 0.35$ Initial total mass of paddy: 50 kg 
Step 1: Calculate dry matter \[ {Total mass} = {dry matter} \times (1 + X_1) \Rightarrow 50 = M_{{dry}} \cdot (1 + 0.13) \Rightarrow M_{{dry}} = \frac{50}{1.13} \approx 44.25\ {kg} \] Step 2: Calculate final total mass \[ M_{{final}} = M_{{dry}} \cdot (1 + X_2) = 44.25 \cdot 1.35 = 59.74\ {kg} \] Step 3: Calculate water added \[ {Water added} = M_{{final}} - M_{{initial}} = 59.74 - 50 = \boxed{9.74\ {kg}} \]