Answer:
Explanation:
A liquid food containing 12% total solids is heated via steam injection at a pressure of 232.1 kPa (see Fig. E3.3). The product starts at a temperature of 50°C and has a flow rate of 100 kg/min, being elevated to a temperature of 120°C. The specific heat of the product varies with its composition as follows:
and the
specific heat of the product at 12% total solids is 3.936 kJ/(kg°C). The goal is to calculate the quantity and minimum quality of steam required to ensure that the leaving product has 10% total solids.
Given
Product total solids in (
) = 0.12
Product mass flow rate (
) = 100 kg/min
Product total solids out (
) = 0.1
Product temperature in (
) = 50°C
Product temperature out (
) = 120°C
Steam pressure = 232.1 kPa at (
) = 125°C
Product specific heat in (
) = 3.936 kJ/(kg°C)
The mass equation is:
Also 
Therefore: 
The energy balance equation is:
kJ/(kg°C)
By substituting values into the energy equation:
From the properties of saturated steam at 232.1 kPa,
= 524.99 kJ/kg
= 2713.5 kJ/kg
% quality = 
Any steam quality above 63.5% will result in higher total solids in the heated product.
