What are the steam requirements and steam economy for a single-effect evaporator process?
The steam requirements for the process are 3269.7 kg/h, and the steam economy is 1.11.
Calculating Steam Requirements:
The calculation for steam requirements in a single-effect evaporator process involves determining the amount of steam needed to concentrate a fruit juice from 5% total solids to 40% total solids. The feed rate of the product is 3000 kg/h, with the feed temperature at 20°C. The specific heat of the liquid feed is 4.05 kJ/(kg°C), and the specific heat of the concentrated product is 3.175 kJ/(kg°C).
To calculate the steam requirements, we first need to find the total heat requirement using the formula:
Q = (P - F) Cp (T p - T f) + P Lv
Where:
Q = Total heat requirement
P = Concentrated product rate
F = Feed rate
Cp = Specific heat of concentrated product
Tp = Temperature of concentrated product
Tf = Temperature of feed
Lv = Latent heat of vaporization of water
Given the values provided:
F = 3000 kg/h
Cf = 0.05
Cp = 0.4
Tf = 20°C
Steam quality = 85%
We can rearrange the formula to find the steam requirement:
S = Q / (Lv / 0.85 - Cf (Tp - Tf))
S = 3269.7 kg/h
Therefore, the steam requirement for the single-effect evaporator process is 3269.7 kg/h.
Calculating Steam Economy:
The steam economy is a measure of the efficiency of the evaporator in producing vapor from the supplied steam. It is calculated as the ratio of the amount of vapor produced to the amount of steam supplied, plus one.
Steam Economy = (P - F) / S + 1
Steam Economy = 1.11
A steam economy of 1.11 indicates that for every unit of steam supplied, 1.11 units of vapor are produced in the process. This value reflects the efficiency of the single-effect evaporator in concentrating the fruit juice.
In conclusion, the steam requirement for the process is 3269.7 kg/h, and the steam economy is 1.11, showcasing the efficiency of the evaporator in producing the desired concentrated product.