?u???10.26?2.874hc?0.051?o?V?0.051??0.0284m ??0.8?849?Co??L22式中孔流系数Co由do/δ?5/3?1.67查图11-10得出,Co?0.8。
2.气体通过板上液层的压降hl
hl???hw?how???hL?0.62?0.06?0.0372m 式中充气系数β的求取如下:
气体通过有效流通截面积的气速ua,对单流型塔板有:
ua?Vs0.312??0.66m/s
AT?Af0.502?0.03动能因子Fa?ua?V?0.662.874?1.12 查化原图11-12得??0.62
3.气体克服液体表面张力产生的压降hσ
4?4?21.19?10?3h????0.002035m
?Lgdo849?9.81?0.0054.气体通过筛板的压降(单板压降)hp和Δpp
hp?hc?hl?h??0.0284?0.0372?0.002035?0.068m
?pp??Lghp?849?9.81?0.068?566.35Pa<0.7kPa(满足工艺要求)。
3.雾沫夹带量ev的验算
3.25.7?10?ua?5.7?10?6?0.66?eV?????3???H?h21.19?100.35?2.5?0.06?? ??Tf???0.012kg液/kg气?0.1kg液/kg气(满足要求)?63.2式中:hf?2.5hL,验算结果表明不会产生过量的雾沫夹带。
4.漏液的验算
漏液点的气速uom
uom?4.4Co?0.0056?0.13hL?h???L/?V?0.0056?0.13?0.06?0.002035?849/2.874 uo10.26??1.59?1.5(不会产生过量液漏) uom6.450?4.4?0.8?6.450m/s筛板的稳定性系数K?5.液泛的验算
为防止降液管发生液泛,应使降液管中的清液层高度Hd?Φ?HT?hw?
Hd?hp?hL?hd
?L??0.00042?hd?0.153?s??0.153???0.0028m
lh0.48?0.0478???wo?Hd?0.068?0.0372?0.0028?0.108m
22??HT?hw??0.5?0.35?0.0538??0.2019m
Hd?Φ?HT?hw?成立,故不会产生液泛。
通过流体力学验算,可认为精馏段塔径及塔板各工艺结构尺寸合适,若要做出最合理的设计,还需重选HT及hL,进行优化设计。
十、塔板负荷性能图
1.雾沫夹带线
5.7?10?6ev?σ??ua??H?2.5hL??T3.2 (1)
式中:ua?VsVs??2.119Vs
AT?Af0.502?0.03hf?2.5hL?2.5?hw?how?2/3??3600Ls???2.5?0.0538?0.00284E?????lw????
2/3??3600Ls???2.5?0.0538?0.00284?1.02???0.48???????0.135?1.088L2/3S将已知数据代入式(1)
?2.119Vs5.7?10???21.19?10?3?0.35?0.135?1.008L2/3s?Vs?0.645?3.025L2/3s (1-1)
?63.2?0.1
在操作范围内,任取几个Ls值,依式(1-1)算出对应的Vs值列于下表:
Ls,m3/s Vs,m3/s 依据表中数据作出雾沫夹带线(1)
2.液相负荷上限线(2)
取液体在降液管中停留时间的下限为4s
Ls,max?HTAf??0.35?0.03?0.00263m3/s 43.液相负荷下限线(3)
取平堰堰上液层高度how?0.006m,E?1.02。
?3600Ls,min?how?0.00284E??lw??2/3?3600Ls??0.00284?1.02???0.48?2/3?0.006
Ls,min?0.000410m3/s
4.漏液线(气相负荷下限线)(4)
hL?hw?how?0.0538?1.088L2/3s
漏液点气速
2/3?uom?4.4?0.8?0.0056?0.130.0538?1.088L?s??0.002035?849/2.874 ?Vs,min?Aouom,整理得:
2/3Vs2?0.477L,mins?0.037
在操作范围内,任取几个Ls值,依式(4-4)算出对应的Vs值列于下表:
Ls,m3/s Vs,m3/s 依据表中数据作出漏液线(4)
5.液泛线(5)
令Hd???HT?hw??hp?hw?how?hd?hc?hl?h??hL?hd (2)
how?1.088L2/3s
?u?????V????hc?0.051?o??V??0.051?s??V??Co???L??CoAo???L?Vs???2.874??0.051?????0.8?0.0304??849??0.292Vs2hl???hw?how??0.6?0.0538?1.088L2/3s??0.033?0.675Lh??0.002035
/3hp?hc?hl?hσ?0.01389Vs2?0.3711L2?0.0318s2/3s222
?L?Ls??2hd?0.153?s??0.153???290.64Ls
?0.48?0.0478??lwho?0.5?0.35?0.0538???0.292Vs2?0.675L2/3s?0.002035??0.0538?1.088L?290.64L2/3s2s22
2Vs2?0.400?6.01L2/3s?994.82Ls (2-2)
在操作范围内,任取几个Ls值,依式(2-2)算出对应的Vs值列于下表:
Ls,m3/s
苯一氯苯分离过程板式精馏塔设计



