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1、Overview of absorption process part 2Principles of Chemical Engineering-CDUTto purify or refine gasexample:in the process of ammonia synthesis,propylene carbonate is used to remove carbon dioxide from the synthetic gasexample:to absorb hydrogen chloride by water to make hydrochloric acidto recycle s
2、ome components that needed in mixed gasexample:to treat coke oven gas with washing oil to recycle arenethe treatment of industrial waste gas example:waste gas discharged by industrial production often contains a small amount of SO2,no,NO2several conditions of gas absorption applicationto make a liqu
3、id product from a certain gasindustrial application of gas absorption7.1 Overview of absorption processPrinciples of Chemical Engineering-CDUTThe following points should be considered when selecting the absorbent solubilityselectivityvolatilityviscosityother pointsThe solubility of absorbent to solu
4、te components should be strong.Absorbent should have good absorption capacity to solutecomponents,while other components in mixed gas should not beabsorbed or slightly absorbed.The vapour pressure of absorbent should be low.That is,thevolatility should be small so as to reduce the loss of solvent.Th
5、e viscosity of absorbent at operating temperature is smallernon-toxicity,non corrosivity,inflammable and non explosion,nonfoaming,low freezing point,low price and stable chemicalproperties.Selection of absorbent7.1 Overview of absorption processPrinciples of Chemical Engineering-CDUTsummaryAbsorptio
6、n is a unit operation to separate gas mixture by using the difference of solubility of each component in a certain liquid solvent.absorbate(solute):A,inert gas(carrier):B,absorbent:S,absorb tail gas:B+A,absorption liquid:A+S7.1 Overview of absorption processPrinciples of Chemical Engineering-CDUTsum
7、maryThe following points should be considered when selecting absorbent:storng solubility,absorbent with good selectivity,small volatility,small viscosity,stable chemical propertiesThe he volatility should be smalvolatility should be smallThe process of gas absorption is carried out in absorption tower,generally adopting counter current operation.the application of absorption：（1）to purify or refinine gas；（2）to make a liquid product from a certain gas；（3）to recycle some components that needed in mixed gas；（4）the treatment of industrial waste gas.7.1 Overview of absorption process