88.2 Equilibrium between liquid and gas 8.2.ISolubility at equilibrium c(1) limitation of 一~平衡溶解度 gas a bsorption The solubility of gas in the liquid At T and P, s+ mixture of gases of A+B, intimate contact。随着两者的不断接触, solute a from gas phase→ transfer to liquid phase,unti液相 中 solute达到un- saturation It is dynamic balance at the moment which concentrations of a are constant within&v. that is the amount of molecules of A entering in L phase the amount of molecules of A escaping from L phase
一.The solubility of gas in the liquid At T and P, S + mixture of gases of A+B, intimate contact 。随着两者的不断接触，solute A from gas phase →transfer to liquid phase, until液相 中solute达到un-saturation。 It is dynamic balance at the moment which concentrations of A are constant within L &V, that is, the amount of molecules of A entering in L phase = the amount of molecules of A escaping from L phase. 8.2.1Solubility at equilibrium 平衡溶解度 §8.2 Equilibrium between liquid and gas ～ ⑴ limitation of gas absorption
821 Solubility at equilibrium~平衡溶解度 从宏观上看,吸收过程终止,即气液两相达 到相平衡。显然,此时A在液相中的浓度最大。 此浓度称为饱和浓度,或溶质A的溶解度CA※ Definition solubility: * A Kg A or A kg Solution M Solution
从宏观上看，吸收过程终止，即气液两相达 到相平衡。显然，此时A在液相中的浓度最大。 此浓度称为饱和浓度，或溶质A的溶解度CA ※ . ∴ Definition solubility: 8.2.1Solubility at equilibrium ～平衡溶解度 3 * kg A = or kg A kg Soluti A on M Solution C
8,2. I Solubility at equilibrium~平衡溶解度 1. Solubility curve~溶解度曲线 Assume: that only one component is transferred between phases According to the phase rule of F=c-p+2,p=2 and there are three components c=3 F=3-2+2=3 There are four variables: Pressure, Temperature, and the concentrations of component A in liquid and gas. The temperature and pressure may be fixed. One concentration may be chosen as the remaining independent variable. The other concentration is then determined
1. Solubility curve ～溶解度曲线 Assume: that only one component is transferred between phases . According to the phase rule of F= c – p + 2, p=2 and there are three components, c=3. F = 3 – 2 + 2 = 3 There are four variables: Pressure, Temperature, and the concentrations of component A in liquid and gas. The temperature and pressure may be fixed. One concentration may be chosen as the remaining independent variable. The other concentration is then determined. 8.2.1Solubility at equilibrium ～平衡溶解度
82.1S0 ibility at equilibrium~平衡溶解度 溶解度曲线的3种表示方式,即3 种气~液平衡相图简称相图)。 t=293K 101.3kPa 60℃ 0 0.4 355N CPA=1. 38cA 0.3 0 0.1 图9-3293K下几种气体在水中的溶解度曲线cA 图中横坐标10°cA中的n值如下 气 体 COz 液相中氨的摩尔分数x 0.0020.0040.0060.0080.010.0120.014 液相中SO2摩尔分数x 例:气相溶质的分压p=20kPa时,水中溶质的平衡浓度 图8-3氨在水中的平衡溶解度 对CO2为102c·(CO2)=0.78,故c(CO2)=0.0078 图8-4101.3kPa下SO2在水中的溶解度 kmol/m3,对SO2为10c·(SO2)=3.37,故c(SO2)= 0.337 kmol/m
8.2.1Solubility at equilibrium ～平衡溶解度 溶解度曲线的3种表示方式，即3 种气～液平衡相图(简称相图)
82.1 Solubility at equilibrium~平衡溶解度 For example Fig 8-4, p=1013kpa, t=40C, all points of(ye,xe) on the curve pertain to(关于) the same temperature and pressure. 2 Factors affecting on solubility According to the phase rule. F=3 In the four variables of T, P, pa and cA, there are three independent variables only where: pa partial pressure of A in gas phase. CA =f(T,P,pA
For example Fig .8-4， p=101.3kpa，t=40℃, all points of (ye , xe ) on the curve pertain to (关于）the same temperature and pressure. 2 Factors affecting on solubility ∵ According to the phase rule, F =3 ∴ In the four variables of T, P, pA and cA, there are three independent variables only. where: pA ～ partial pressure of A in gas phase. 8.2.1Solubility at equilibrium ～平衡溶解度 ( A ) * C = f T, P,p A