Page 352 - Distillation theory

P1: JPJ/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH
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326 Short Glossary

located on separatrix sharp distillation re- jectory from the product point to the feed
gions for given product points and re- cross-section.
flux ratio and satisfy the material bal- Section sharp split product of a section
ance in feed cross-section: x f −1 ∈ [x f −1 ] ∈ contains only the part of feed compo-
sh,R sh,R
Reg sep,r and x f ∈ [x f ] ∈ Reg sep,s . nents.
Operating condition of trajectory tear-off Segment of possible feed cross-section com-
L/V > K t1 if only one tear-off point t 1 positions the set of possible of feed
j
t2 t1
exists; K > L/V > K if both points t 1 cross-section composition points x f −1 or
j
j
and t 2 exist on reversible distillation tra- x f at reflux greater then minimum.
jectory. Separatrix element of section trajectories
Pitchfork region (Reg pitch ) region of con- bundle (Reg sep,r or Reg sep,s or Reg sep,e )
centration simplex where the section tra- separatrix element that belongs to
jectory at certain reflux or reboil ra- both working and unworking bundles
R
tios leaves its own distillation region and of section trajectories Reg sep ≡ Reg •
w
R
comes into another distillation region. Reg .
Possible sharp split split whose product Separatrix min-reflux region (Reg min,R ,
sep,r
points belong to section product regions Reg min,R ) separatrix element of work-
sep,s
x D ∈ Reg and x B ∈ Reg . ing bundle of section trajectories for
D B
(k)
Product region (Reg (k) or Reg ) region given reflux and product point containing
D B
2
+
of k-component boundary element of tear-off point S and N and free from
1
2
concentration simplex in which section points S and N : {S → ··· → N } ≡
+
−
2
2
+
+
product points can be situated. S ⇒ N (in abbreviated form S – N )
Product simplex (Reg ) simplex whose to which belong the feed cross-section
simp
vertexes are stationary points of distilla- compositions at minimum reflux: x f −1 ∈
tion subregion and their number is equal Reg min,R and x f ∈ Reg min,R .
sep,s
sep,r
sh,R
to the total number of components. Separatrix sharp split region (Reg sep,r ,
sh,R
Reversible distillation region of section Reg sep,s ) separatrix element of work-
(Reg h rev,r , Reg l rev,s , Reg m ) unification ing bundle of section trajectories for
rev,e
of several regions of components’ or- given reflux and product point contain-
2
1
der for which one and the same compo- ing tear-off points S , S , and N + and
2
1
nent appears to be (1) the most heavy- free from point N : {S → S → ··· →
−
1
volatile for rectifying section, (2) the most N } ≡ S ⇒ N + (in abbreviated form
+
1
+
light-volatile for stripping section, and S – N ) to which belong the feed cross-
(3) middle-volatile between top and en- section compositions at sharp split: x f −1 ∈
trainercomponentsforextractivesection. Reg sh,R and x f ∈ Reg sh,R .
sep,r
sep,s
Rule of connectedness condition satisfied Sharp split split when each of the prod-
to product points at R =∞ and N =∞. ucts contains only the part of feed com-
The stable node N of the top product ponents. There some kinds of sharp splits:
+
D
boundary element of distillation region direct split1:2,3,..., n; indirect split 1,
at infinite reflux Reg ∞ and the unstable 2,..., n – 1 : n; intermediate splits 1,...,
D
−
node N of the bottom product boundary k:k + 1,..., n; preferred split 1,..., n –
B
element of distillation region at infinite 1 : 2,..., n; splits with distributed compo-
−
reflux Reg ∞ should coincide (N ≡ N ), nent 1,... ,k:k,k + 1,..., n.
+
B D B
or should be connected with each other by Sharp split region (Reg i: j , Reg i: j ,
sh,s
sh,r
i: j
+
−
the bond (N → N ) or chain of bonds Reg sh,e ) region of concentration sim-
B
D
in direction to the bottom product. plex in which working bundles of sec-
Section composition profile (x D → x f −1 or tion trajectories for given sharp split in a
x B → x f ) part of working section tra- section (i D : j D or i B : j B or i DE : j DE ) are