2) Flash Distillation (or Single-Stage Contact) A mixture of 60 mole % n-heptane and 40 mole % toluene is vaporized at 101.325 kPa (absolute) until 40 moles of vapor and 60 moles of liquid in equilibrium with each other are produced. This occurs in a single- stage system and the vapor and liquid are kept in contact until equilibrium is achieved. Calculate the composition of the vapor and liquid. Note: Assume the system exhibits ideal behavior (which it mostly does), e.g. Raoult's Law applies and an Antoine's Vapor Pressure correlation is a sufficiently accurate model of component vapor pressure.

A single effect evaporator is used to concentrate 10 000 kg / hr of tomato juice from 5% total solids to 30% total solids. The juice enters the Evaporator at 20 ° C. The evaporator is operated on Steam (80% quality) at 143.27 kPa. The vacuum in the evaporator allows the juice to boil at 75 ° C. The specific heat of the dilute material is 4.1 kJ / (kg ° C) and the concentrate product is 3.1 kJ / (kg ° C). Count it a. Steam demand rate = ..... kg / hour. b. Steam economy when condensate temperature is released at 75 ° C. = .... (kg of water evaporated / kg of steam)

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Fruit juices at 25 °C containing 5% total solids were concentrated via a single effect evaporator. The evaporator is operated in a vacuum at an evaporation temperature of 80 °C, and 85% quality steam is supplied at 169.06 kPa. The desired concentration of the final product is 40% total solids. The rate of concentrated product leaving the evaporator is 3000 kg / hour. The specific heat of fruit juice is 4.05 kJ / (kg °C), and the concentrated product 3.175 kJ / (kg °C). Count : a. The required steam rate is = Answer kg / hour. b. Steam economy if the condensate temperature cannot be released at 90 °C. = Answer (kg evaporated air / kg vapor)