当前位置:首页 > 传质分离过程课后习题答案
第一章 绪论
略
第二章习题
1. 计算在0.1013MPa和378.47K下苯(1)-甲苯(2)-对二甲苯(3)三元系,当x1 = 0.3125、x2 =0.2978、x3 =0.3897时的K值。汽相为理想气体,液相为非理想溶液。并与完全理想系的 K值比较。已知三个二元系的wilson方程参数(单位: J/mol ):
λ12-λ11=-1035.33; λ12-λ22=977.83 λ23-λ22=442.15; λ23-λ33=-460.05 λ13-λ11=1510.14; λ13-λ33=-1642.81 在T =378.4 K时液相摩尔体积(m3/kmol)为: =100.91×10 -3 ;
=177.55×10 -3 ;
=136.69×10 -3
安托尼公式为(ps:Pa ; T:K ): 苯:1n 甲苯:1n
=20.7936-2788.51/(T-52.36); =20.9065-3096.52/(T-53.67);
=20.989 1-3346.65/(T-57.84);
对 -二甲苯:1n 解:
由Wilson方程得:
V2llV1Λ12=exp[-(λ
12
-λ11)/RT]
177.55?1033 =100.91?10×exp[-(1035.33)/(8.314×378.47)]=2.4450
Λ
31
21
=0.4165 Λ
13
=0.8382 Λ
=1.2443
1
Λ23=0.6689 Λ32=1.5034 ln
13
γ
1
=1-ln(Λ
12
X2+Λ
X3)-[
X3?31X1?21X2??]
X1??12X2??13X3X1?21?X2?X3?23X1?31?X2?32?X3=0.054488 γ1=1.056
同理,γ2=1.029; γ3=1.007
lnP1S=20.7936-2788.51/(378.47-52.36)=12.2428, P1S=0.2075Mpa lnP2S=20.9062-3096.52/(378.47-53.67)=11.3729, P2S=0.0869Mpa lnP3S=20.9891-3346.65/(378.47-57.84)=10.5514, P3S=0.0382Mpa 作为理想气体实际溶液,
?1P1SK1=P=2.16, K2=0.88, K3=0.38003 若完全为理想系,
P1SK1=P=2.0484 K2=0.8578 K3=0.3771
2. 在361K和4136.8kPa下,甲烷和正丁烷二元系呈汽液平衡,汽相含甲烷0.60387%( mol ),与其平衡的液相含甲烷0.1304%。用R-K 方程计算
和
Ki值。
.50.42748R2?Tc21解:a11=a22=b1=
pc1=3.222MPa ? dm6 ? k0.5 ? mol-2 =28.9926 MPa?dm6?k0.5?mol-2 =0.0298 dm3mol-1
2
.50.42748R2?Tc22pc20.08664R2?Tc1pc1.50.42748R2?Tc22b2=
pc2=0.0806 dm3mol-1
其中Tc1=190.6K, Pc1=4.60Mpa Tc2=425.5K, Pc2=3.80Mpa 均为查表所得。
a12=√a11?a22=9.6651MPa?dm6?k0.5?mol-2 液相:
a=a11x12+2a12x1x2+a22x22
=3.22×0.13042+2×9.6651×0.1304×0.8696+28.9926×0.86962 =24.1711
b=b1x1+b2x2=0.0298×0.1304+0.0806×0.8696=0.0740 由R-K方程: P=RT/(V-b)-a/[T0.5V(V+b)]
0.0083145?36124.1711l0.5llV?0.0740361V(V?0.0740) mmm4.1368=-
解得 Vml=0.1349 ln
??1l=ln[V/(V-b)]+[bi/(V-b)]-2Σ
yiaij/bmRT1.5*ln[(V+b)/V]+abi/b2RT1.5{ [ln[(V+b)/V]-[b/(V+b)] }-ln(PV/RT)
0.13490.0298)?l?ln1=ln0.1349?0.0740+0.1349?0.0740-
(0.1349?0.07402?(0.1304?3.222?0.8696?9.6651)0.13400.0740?0.0083145?3611.5×ln()+ 24.1711?0.02980.1347?0.07400.13490.07402?0.0083145?3611.5×[ln() 0.07404.1368?0.1349-0.1347?0.0740]-ln0.0083145?361
=1.3297
3
??1l=3.7780
?l?l??2同理ln=-1.16696, 2=0.3113
汽相:a = 3.222×0.603872+2×9.6651×0.60387×0.39613+28.9926×0.396132 = 10.3484
b=0.0298×0.60387+0.0806×0.39613=0.0499
0.0083145?36110.3484v0.5vvV?0.0499361V(Vmm?0.0499) 由4.1368=m-
得
vVm=0.5861
v10.58610.0298lnΦ=ln(0.5861?0.0499)+0.5861?0.0499-
2?(0.60387?3.222?0.39613?9.66510.5861?0.049910.3484?0.0298?ln()?0.58610.0499?0.0083145?3611.50.04992?0.0083145?3611.5
0.5861?0.04990.04994.1368?0.5861()?0.58610.5861?0.0499]-ln(0.0083145?361) ×[ln
=0.0334942 故Φ=1.0341
?l?l??2同理,ln=-0.522819, 2=0.5928
v?l?1故K1=y1/x1=0.60387/0.1304=4.631 ( K1=1/Φ)
v11?0.60387K2=y2/x2=1?0.1304=0.4555
3. 乙酸甲酯(1)-丙酮(2)-甲醇(3)三组分蒸汽混合物的组成为y1=0.33,
y2=0.34,y3=0.33(摩尔分率)。汽相假定为理想气体,液相活度系数用Wilson
方程表示,试求50℃时该蒸汽混合物之露点压力。
解:由有关文献查得和回归的所需数据为: 【P24例2-5,2-6】 50℃时各纯组分的饱和蒸气压,kPa
4
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