Principle Steam distillation

diagram of how economically clean plant wastewater streams. steam use stripping gas remove hydrocarbons waste water. method effective when volatile organic compounds (i.e. chlorine) have lower boiling points water or have limited solubility in water.

when mixture of 2 practically immiscible liquids heated while being agitated expose surface of each liquid vapor phase, each constituent independently exerts own vapor pressure function of temperature if other constituent not present. consequently, vapor pressure of whole system increases. boiling begins when sum of vapour pressures of 2 immiscible liquids exceeds atmospheric pressure (approximately 101 kpa @ sea level). in way, many organic compounds insoluble in water can purified @ temperature below point @ decomposition occurs. example, boiling point of bromobenzene 156 °c , boiling point of water 100 °c, mixture of 2 boils @ 95 °c. thus, bromobenzene can distilled @ temperature 61 °c below normal boiling point.