Mass Balance in a Single-Stage Evaporator

Degrees Brix (symbol °Bx) is a measure of the dissolved sugar-to-water mass ratio of a liquid.

Snapshot 1: orange juice concentration from 12 °Bx

Snapshot 2: making tomato paste, 28 °Bx, from tomato juice, 4.5 °Bx

Snapshot 3: 1:4 concentration of a solution

This Demonstration calculates the amount of vapor and concentrate produced by a single-stage evaporator. The adjustable parameters are the feed, expressed in terms of total mass or mass flow rate units, and the concentrations of the feed and concentrate, expressed as mass fractions on a wet weight basis. The mass balance is based on solving the equation , where and are the amount or flow rate of the concentrate and the feed, respectively. and are the concentrations of the feed and concentrate, respectively. The amount or flow rate of the vapor, , is calculated from .

The , , and values are entered with sliders and the Demonstration calculates and displays the corresponding values of and . The Demonstration also plots versus and versus for the current values of and . The current values of and corresponding to the chosen are marked as purple dots on the plots. The maximum limit on the axis may also be set with a slider.

References:

R. L. Earle and M. D. Earle, Unit Operations in Food Processing, NZIFST, Inc., 1983.

M. Karel and D. B. Lund, Physical Principles of Food Preservation, 2nd ed., New York: Marcel Dekker, 2003.

R. T. Toledo, Fundamentals of Food Process Engineering, 3rd ed., New York: Springer, 2007.

R. P. Singh, "Single-Effect Evaporator".