When a component is transferred from a gas phase to solution in a liquid phase, the latent heat associated with the condensation is evolved. In the operations where mass transfer proceeds by equimolar counter diffusion, as in distillation or in operations where latent heat effect are small, as in liquid –liquid extraction, gas absorption in dilute solutions, and leaching, heat transfer is of minor importance as a rate controlling mechanism. In others, particularly where there is a net transfer of mass from gas phase to condensed phase or vice versa, the heat transfer rate is important. In these cases, heat transfer significantly limits the rate at which mass can be transferred.
Of those operations where both heat transfer and mass transfer affect the rate, humidification and dehumidification involve two components and two phases. The liquid phase, most often water, is single component, and the gas phase consists of a non-condensable gas, usually air, in which some vapor from the liquid phase is present.
When a component is transferred from a gas phase to solution in a liquid phase, the latent heat associated with the condensation is evolved. In the operations where mass transfer proceeds by equimolar counter diffusion, as in distillation or in operations where latent heat effect are small, as in liquid –liquid extraction, gas absorption in dilute solutions, and leaching, heat transfer is of minor importance as a rate controlling mechanism. In others, particularly where there is a net transfer of mass from gas phase to condensed phase or vice versa, the heat transfer rate is important. In these cases, heat transfer significantly limits the rate at which mass can be transferred.
Of those operations where both heat transfer and mass transfer affect the rate, humidification and dehumidification involve two components and two phases. The liquid phase, most often water, is single component, and the gas phase consists of a non-condensable gas, usually air, in which some vapor from the liquid phase is present.
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