优秀毕设常压二元精馏筛板塔设计Word格式.docx
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优秀毕设常压二元精馏筛板塔设计Word格式.docx
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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℃
0.000.00100
1.9017.0095.5
7.2138.9189.0
9.6643.7586.7
12.3847.0485.3
16.6150.8984.1
23.3754.4582.7
26.0855.8082.3
32.7358.2681.5
39.6561.2280.7
50.7965.6479.8
51.9865.9979.7
57.3268.4179.3
67.6373.8578.74
74.7278.1578.41
89.4389.4378.15
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
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:
取φ=0.6
HT+hw≥Hdφ,Hd≤(0.4+0.04)/0.6=0.7333
h0)2=4611.55Ls2
hc=0.051(Vs/A0C0)2×
(ρv/ρl)=5.658Vs2
hl'
=0.024+1.293Ls2/3
hp=hc+hl'
=0.024+1.293Ls2/3+5.658Vs2
Hd=0.7333=hl+hd+hp
=0.1+5.388Ls2/3+4611.55Ls2+5.658Vs2
∴Vs2=0.112-0.952Ls2/3-815.05Ls2
∴ls=0.000121m3/s
HT/Ls,Ls=Af×
0.000076)/5=0.0000076
hl=hw+how=0.04+2.434ls2/3m
Uom=Vsmin/A0=Vsmin/0.003024
(ρl/ρv)]0.5
Vsmin=0.0104[7.628+370.19ls2/3]0.5
hf=2.5hl=0.1+6.085Ls2/3
Ug=Vs/(AT-Af)=Vs/0.0465
ev=(0.00
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