Nþ1 xt

Cx ¼ ¼

(27)

Z Z dx

R xt dx

mðxÞ— 1

dn ¼ N þ 1 ffi

0 xb

xð1 —

xÞ ln½aðxÞ]

(20)

xb   xð1—xÞ ln½aðxÞ]

Z

G 。Cy

Cx。

or for any two stages in the   column

hHETPi ¼ N ¼ a

ky  þ kx

(28)

n1

Z

dn ¼ ni — nj ffi

nj

xi

Z dx

xð1 — xÞ ln½aðxÞ]

xj

(21)

Although the calculations look overwhelming, they are actually quite easy to perform numerically—in fact, these integrals are substantially easier to evaluate than the sums discussed  earlier。  Further,  there  is  no  restriction  on    these

Note that the restriction of the Fenske equation to constant relative volatility has been  removed。

Next, the packed-height calculation can be   approximated

equations to constant relative  volatility。

Even without evaluating these integrals some important conclusions can be drawn。 First, note that hHETPi now depends explicitly on the bottom and top compositions。 So,   it

0

Z

Z ¼ HETPðnÞdn ¼

xt

Z  HETP  x  dn dx

dx

is not enough to just report hHETPi, one must also report the top and bottom compositions as well。 Second, as the bottom and top compositions depend on the packed depth, we   should

Nþ1 xb

xt

expect to see that   HETP   is packed depth dependent。  Indeed,

20–22

Z 。 1

mðxÞ。。 1

。 ln½mðxÞ]

this  is  oftentimes observed,

and  the  effect  is sometimes

kyam

þ kxam

xð1 — xÞ ln½aðxÞ]

dx

mðxÞ— 1

even    included    in    packed-column    mass-transfer correla-

4,23,24

xb tions。 Figure 3 shows how Cy  and Cx  vary with the  mole

fraction of the light component for a fictitious binary    mixture

with a ¼ 1。2 and the bottom composition fixed at xb  ¼ 0。05。

Dimensional  analysis

First, we consider expressions for the mass-transfer coefficients

hHETPi ¼ N ffi G

R xt dx

xb   xð1—xÞ ln½aðxÞ]

R xt 。

xb

1

kx am

。。 mðxÞ

xð1—xÞ ln½aðxÞ]

。  ln½mðxÞ]

mðxÞ—1

ky  ¼ KyðvV; qV; lV; cV; DV; deÞ

上一篇:注塑模具中设计内部销设计英文文献和中文翻译
下一篇:机器视觉维护检测与跟踪系统英文文献和中文翻译

移动码头的泊位分配问题英文文献和中文翻译

纤维素增强的淀粉-明胶聚...

多极化港口系统的竞争力外文文献和中文翻译

阻尼减震平台的设计英文文献和中文翻译

超精密自由抛光的混合机...

旋转式伺服电机的柔性电...

过程约束优化数控机床的...

压疮高危人群的标准化中...

STC89C52单片机NRF24L01的无线病房呼叫系统设计

AES算法GPU协处理下分组加...

浅论职工思想政治工作茬...

基于Joomla平台的计算机学院网站设计与开发

上海居民的社会参与研究

从政策角度谈黑龙江對俄...

浅谈高校行政管理人员的...

提高教育质量,构建大學生...

酵母菌发酵生产天然香料...