水乙醇体系常压二元精馏筛板塔设计Word文档下载推荐.doc
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水乙醇体系常压二元精馏筛板塔设计Word文档下载推荐.doc
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2.1混合参数计算----------------------------------------
2.2塔径计算--------------------------------------------
2.3塔板详细计算----------------------------------------
2.4校核-------------------------------------------------
2.5负荷性能图------------------------------------------
三、筛板塔数据汇总----------------------------------------
3.1全塔数据--------------------------------------------
3.2精馏段和提馏段的数据-------------------------------
四、讨论与优化--------------------------------------------
4.1讨论-------------------------------------------------
4.2优化-------------------------------------------------
五、辅助设备选型------------------------------------------
5.1全凝器----------------------------------------------
5.2泵---------------------------------------------------
一、总体设计计算
1.1汽液平衡数据(760mmHg)
乙醇%(mol) 温度
液相X 气相Y ℃
0.00 0.00 100
1.90 17.00 95.5
7.21 38.91 89.0
9.66 43.75 86.7
12.38 47.04 85.3
16.61 50.89 84.1
23.37 54.45 82.7
26.08 55.80 82.3
32.73 58.26 81.5
39.65 61.22 80.7
50.79 65.64 79.8
51.98 65.99 79.7
57.32 68.41 79.3
67.63 73.85 78.74
74.72 78.15 78.41
89.43 89.43 78.15
1.2物料衡算
1.1-1已知:
1.进料:
F=6kmol/hq=0Xf=0.45
p顶=4KPa单板压降≤0.7KPa
5.选定:
R/Rmin=1.6
D=(Xf-Xw)/(Xd-Xw)×
F
=(0.45-0.01)/(0.88-0.01)×
6=3.03kmol/h
W=F-D=6-3.03=2.97kmol/h
查y-x图得Xd/(Rmin+1)=0.218
∴Rmin=3.037∴R=1.6Rmin=4.859
∵饱和蒸汽进料∴q=0
L=RD=4.859×
3.03=14.723kmol/h
V=(R+1)D=(4.859+1)×
3.03=17.753kmol/h
L'
=L+qF=14.723+0×
6=14.723kmol/h
V'
=V-(1-q)F=17.753-(1-0)×
6=11.753kmol/h
1.3操作线及塔板计算
1.精馏段操作线:
Y=R×
X/(R+1)+Xd/(R+1)
∴Y=0.829X+0.150
2.提馏段操作线:
Y=(L'
/V'
)×
X-(W/V'
Xw
∴Y=1.253X-0.00025
3.理论塔板的计算
利用计算机制图取得理论板数
Nt=29.33块,其中精馏段塔板Nt1=26.85块,第27块为加料板,提馏段Nt2=2.48块。
1.4全塔Et%和Np的计算
1.精馏段:
t=(t顶+t进)=(79.25+87.32)/2=83.285℃
Xa=0.34Xb=1-Xa=0.66
Ya=0.59Yb=1-Ya=0.41
查得液体粘度共线图μa=0.382cp,μb=0.592cp
αμL=YaXbμL/XaYb=1.454
查得:
Et1%=0.49(αμL)-0.245=0.5471
Np1=Nt1/Et1=49.08
2.提馏段:
t=(t底+t进)/2=(99.9+87.32)/2=93.61
Xa=0.045Xb=1-Xa=0.955
Ya=0.27Yb=1-Ya=0.730
查得液体粘度共线图μa=0.468cp,μb=0.532cp
μL=ΣXiμi=0.045×
0.468+0.955×
0.532=0.5291
αμL=YaXbμL/XaYb=4.15
Et2%=0.49(αμL)-0.245=0.346
Np2=Nt2/Et2=7.17
∴Np=Np1+Np2=49.08+7.17=56.25
圆整为57块
其中精馏段49块,提馏段8块。
二混合参数计算
2.1混合参数计算
溶质C2H5OH分子量:
Ma=46.07kg/kmol
溶剂H2O分子量:
Mb=18.016kg/kmol
ρa=0.789g/mlρb=1.000g/ml
(1)精馏段:
进料板液体温度:
t进=87.32℃
塔顶温度:
t顶=79.25℃
tm=(87.32+79.25)/2=83.285℃
Xm=0.34Ym=0.59
μa=0.382cpμb=0.592cp
Ml=Xm×
Ma+(1-Xm)Mb=0.34×
46.07+(1-0.34)×
18.016
=27.55kg/kmol
Mg=Ym×
Ma+(1-Ym)Mb=0.59×
46.07+(1-0.59)×
=34.56kg/kmol
质量分率:
Wa=XmMa/Ml=0.34×
46.07/27.55=0.6855
Wb=1-Wa=1-0.6855=0.3145
1/ρl=Wa/ρa+Wb/ρb=0.6855/0.789+0.3145/1.00
ρl=845.1kg/m3
P=105325Pa
ρv=PMg/RT=105325×
34.56/(8314×
(273.15+79.25))
∴ρv=1.2424kg/m3
(2)提馏段:
t进=87.32℃t底=99.9℃tm=93.61℃
Xm=0.045Ym=0.27
Ma+(1-Xm)Mb=0.045×
46.07+(1-0.045)×
=19.278kg/kmol
Ma+(1-Ym)Mb=0.27×
46.07+(1-0.27)×
=25.59kg/kmol
Wa=XmMa/Ml=0.045×
46.07/19.278=0.1275
Wb=1-Wa=1-0.1275=0.8725
1/ρl=Wa/ρa+Wb/ρb=0.1275/0.789+0.8725/1
ρl=1.0341kg/m3
25.59/(8314×
(273.15+93.16))
∴ρv=0.8839kg/m3
σa=58.46dyn/cm,σb=18.4dyn/cm
σ=ΣXσ=0.688×
58.46+(1-0.688)×
18.4=45.96dyn/cm
2.2塔径计算
Ls=L×
Ml/(3600ρl)=442.03×
27.55/(3600×
845.1)
=0.004m/s
Vs=V×
Mv(3600ρv)=543.39×
34.56/(3600×
1.1952)
=4.365m/s
tm=83.285℃
此温度下液体的表面张力
σa=18.2dyn/cmσb=67.3dyn/cm
σ=Xmσa+(1-Xm)σb=0.34×
18.2+0.66×
67.3=50.606
两相流动参数:
Flv=Ls/Vs×
(ρl/ρv)0.5
=0.00013/0.137×
(845.1/1.2424)0.5=0.0247
初设板间距HT=0.5m清液层高度HL=0.06m
∴HT-HL=0.44m
Cf,20=0.093
液气气相负荷因子:
Cf=[(σ/20)0.20]×
Cf,20=0.112
气体气速:
un,f=Cf[(ρl-ρv)/ρv]0.5
=0.112×
[(845.1-1.2424)/1.2424]0.5=2.919m/s
空速:
un=0.7un,f=0.7×
2.919=2.0433m/s
初估塔径:
D=(Vs/(0.785un))0.5
=(0.137/(0.785×
2.0433))0.5=0.292m
圆整为D=0.3m
uf=vs/(0.785×
D2)=0.137/(0.785×
0.32)=1.939m/s
实际泛点百分率:
uf/un,f=1.939/2.919=0.6643
Ls=L’×
Ml/(3600ρl)
=14.723×
19.278/(3600×
1034.1)=0.000076m/s
Vs=V’×
Mv(3600ρv)
=11.753×
25.59/(3600×
0.8839)=0.0945m/s
tm=93.61℃
σ=Xmσa+(1-Xm)σb=0.045×
18.2+0.955×
67.3=65.091
=0.000076/0.0945×
(1034.1/0.8839)0.5=0.0275
Cf,20=0.0947
Cf=[(σ/20)0.20]×
Cf,20=0.1199
un,f=Cf[(ρl-ρv)/ρv]0.5
=0.1199×
[(1034.1-0.8839)/0.8839]0.5=4.099m/s
4.099=2.869m/s
=(0.0945/(0.785×
2.869))0.5=0.205m
圆整为D=0.25m
D2)=0.0945/(0.785×
0.252)=1.926m/s
uf/un,f=1.926/4.099=0.470
2.3塔板的详细设计
1.流动型式:
选取单溢流型
2.堰的计算:
堰长取lw=0.6D=0.6×
0.3=0.18m
堰高hw=0.04m
lh/lw2.5=0.00013×
3600/0.182.5=34.046
又lw/D=0.6查得:
E=1.03
堰上清液高how=0.00284E(Lh/lw)2/3=0.00553m
清液层高度hl=hw+how=0.04+0.00553=0.04553m
降液管底隙高ho=hw-0.008=0.032m
0.25=0.15m
3600/0.152.5=53.705
又lw/D=0.6查得:
堰上清液高how=0.00284E(Lh/lw)2/3=0.00137m
清液层高度hl=hw+how=0.04+0.00137=0.04137m
降液管底隙高ho=hw-0.012=0.028
3.塔板的布置
(1)精馏段:
选取碳钢为筛板的材料,板厚δ=4mm,孔径do=6mm
取孔中心距t=18mm,t/do=3
开孔率φ=Ao/Aa=0.907/(t/do)2=0.1008
Ao—开孔面积,Aa—开孔区面积
Af—降液管截面积,At—空塔截面积
取外堰前的安定区:
Ws1=0.02m
取内堰前的安定区:
Ws2=0.02m
边缘区:
Wc=20mm(D≤2.5m)
lw/D=0.6
r=D/2-Wc=0.3/2-0.02=0.13m
Wd=0.1×
0.3=0.03
x=D/2-(Wd+Ws)=0.1
An=2[x×
(r2-x2)0.5+r2arcsin(x/r)]=0.0463
开孔区面积/塔板面积=0.0463/(0.785×
0.32)=0.6553m2
筛孔总面积A0=An×
φ=0.0463×
0.1008=0.004667m2
孔数:
N=A0/u=0.004667/(0.785×
0.0062)=165.15
取整:
N=166孔
开孔率φ=Ao/Aa=0.907/(t/do)2=0.1008
Ws1=20mm
Ws2=20mm
r=D/2-Wc=0.25/2-0.02=0.105m
0.25=0.025
x=D/2-(Wd+Ws)=0.08
(r2-x2)0.5+r2arcsin(x/r)]=0.030
开孔区面积/塔板面积=0.030/(0.785×
0.252)=0.7856m2
φ=0.030×
0.1008=0.003024m2
N=A0/u=0.003024/(0.785×
0.0062)=107.006
N=108孔
2.4校核
(1)精馏段
1.压降校核
δ=4mm,do/δ=1.5,查图得Co=0.78
Hc—干板压降,Co—孔流系数
下板阻力Hc=0.051(ρv/ρl)×
(Uo/Co)2
Uo筛孔汽速,Uo=Vs/Ao=0.137/0.004667=29.355
∴Hc=01062(m液柱)
Hl—液层有效阻力,Fo—气相动能因子
Ua=Vs/(At-2Af)=0.137/0.063162=2.169
Fa=Ua(pv)0.5=2.4176
查表得β=0.6
Hl=β(hw+how)=0.6×
0.04553=0.02732m(液柱)
总压降--Hp=Hl+Hc=0.1335(m液柱)≤0.6kg液/kg气
∴合格
2.液沫夹带的校核
Ug--气体通过有效截面的面积的速率
Ug=Vs/(At-Af)=2.0477m/s
hf板上鼓泡层高度Φ物系的起泡系数
hf=hl/Φ=0.07167m,Φ=0.6
∴Ev=(5.7E10-3/σ)(Ug/(Ht-hf))3.2
=0.01392kg(液)/kg(汽)≤0.1kg(液)/kg(汽)
∴不产生过量液沫夹带,合格.
3.液泛校核
Hd降液管液面高度,hd液相流经降液管的阻力
hd=0.153(Ls/(lw×
ho))2=0.0000779m
Hd=hw+how+hd+Hp=0.179m,Φ=0.6
Hd/φ=0.2984m≤0.44m
∴合格,不会产生液泛
4.停留时间的校核
Af=0.003744m2
τ=Af×
Ht/Ls=0.003744×
0.5/0.004=27.91≥(3∽5s)
5.漏液校核
hσ-表面张力压头,Uom-漏点气速,Co-孔流系数
hσ=4σ/9810ρl×
do=0.00407(m液柱)
do/δ=1.5查图得Co=0.78
Uom=4.4Co×
((0.0056+0.13hl-hσ)×
ρl/ρv)0.5=6.381m/s
K=Uo/Uom=4.6≥1.5
∴操作弹性大,不会发生严重漏液,合格。
Hc-干板压降,Co-孔流系数
Uo筛孔汽速,Uo=Vs/Ao=0.0945/0.003024=31.25
∴Hc=0.0700(m液柱)
Hl—液层有效阻力,Fo气相动能因子
Ua=Vs/(At-2Af)=2.153
Fa=Ua(pv)0.5=2.0239
Hl=β(hw+how)=0.02482m(液柱)
总压降--Hp=Hl+Hc=0.09482(m液柱)≤0.6kg液/kg气
Ug=Vs/(At-Af)=2.032m/s
hf板上鼓泡层高度Φ物系的起泡系数
hf=hl/Φ=0.04137m,Φ=0.6
∴Ev=(5.7E10-3/σ)(Ug/(Ht-hf))3.2
=0.01453kg(液)/kg(汽)≤0.1kg(液)/kg(汽)
∴不产生过量液沫夹带,合格.
ho))2=0.0000501m
Hd=hw+how+hd+Hp=0.1362m,Φ=0.6
Hd/φ=0.2270m≤0.44m
∴合格,不会产生液泛
Af=0.0026m2
Ht/Ls=0.0026×
0.5/0.000076=17.105≥(3∽5s)
hσ=4σ/(9810ρl×
do)=0.00428(m液柱)
ρl/ρv)0.5=7.915m/s
K=Uo/Uom=3.948≥1.5
2.5负荷性能图
1.液相下限线
取how=0.006mE=1.04
how=0.00284E(3600ls/lw)2/3
∴ls=0.000145m3/s
2.液相上限线
取τ=5s
HT/Ls
Ls=Af×
HT/τ=(0.5×
0.003744)/5=0.0003744
3.漏液线
hl=hw+how=0.04+2.155ls2/3m
Uom=Vsmin/A0=Vsmin/0.2028
Uom=4.4C0[(0.0056+0.13hl-hσ)×
(ρl/ρv)]0.5
Vsmin=0.016[4.578+190.56ls2/3]0.5
4.过量液沫夹带线:
取ev=0.1,E=1.04
hf=2.5hl=0.1+5.388Ls2/3
Ug=Vs/(AT-Af)=Vs/0.0669
ev=(0.0057/σ)[Ug/(HT-hf)]3.2
Vs=0.459-6.176Ls2/3
5.液泛线
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