LearnChemE

#### Single-effect Evaporators: Interactive Simulations

The first simulation plays directly in a browser. The optional simulation was prepared using Mathematica and can be viewed using the free Wolfram player

##### Simulation: Single-Effect Evaporation

This demonstration shows the efficacy of single-effect evaporation of a dilute sugar solution. The saturated or unsaturated liquid is fed into a tank, which contains a steam-fed heat exchanger. The user may adjust the feed flow rate and feed temperature of the feed solution. The conditions of each inlet and outlet stream are shown in colored boxes, with green boxes representing the sugar solution or vapor from the sugar solution, and red boxes representing the steam fed into the heat exchanger.

Try to answer these questions before determining the answer with the simulation. We suggest that you write down the reasons for your answers.

1. As the feed flow rate to a single-effect evaporator increases, how does the flow rate of evaporated water change? Why?
2. As the feed pressure and temperature increase so the feed to a single-effect evaporator remains a saturated liquid, how does the flow rate of evaporated water change? Why?

This simulation runs in your browser. Try to predict the behavior when a parameter changes before using a slider to change that parameter.

##### Simulation: Mass Balance in a Single-stage Evaporator (optional)

This Demonstration calculates the amount of concentrate and vapor produced by a single-stage evaporator from a given amount of feed. The adjustable parameters are the feed’s mass or mass flow rate and the concentrations of the feed and concentrate expressed as mass fractions on a wet basis.

Try to answer these questions before determining the answer with the simulation. We suggest that you write down the reasons for your answers.

1. For a single-effect evaporator used to concentrate a solute in water, as the weight fraction of solute in the feed increases (for a given mass feed rate), does the mass flow rate of the vapor increase or decrease if the solute concentration in the outlet stream remains the same?
2. For a fixed feed, if the solute concentration in the outlet stream doubles, how does the flow rate of the vapor stream change? Does it double, more than double, or less than double?