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Claims  |
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What is claimed is:
1. A baffle tray tower for distillation or absorption of polymerizable
unsaturated compounds comprising a tower body, a plurality of stages of
baffle tray means disposed within said tower body, and partition plates,
each disposed within said tower body transversing a vertically middle area
of a curtain zone defined between two adjacent stages of said baffle tray
means so as to divide the curtain zone into an upper curtain zone for
mainly passing a gas therethrough and a lower curtain zone for mainly
passing a liquid therethrough such that the upper curtain zone just below
one baffle tray means allows the gas to be directed therethrough at
increased speed to the liquid falling from said one baffle tray means.
2. The baffle tray tower of claim 1, in which said baffle tray means in
each of the stages comprises a baffle tray and the edges of said baffle
trays from which the liquid flows down are in parallel with each other.
3. The baffle tray tower of claim 2, in which the upper surface of the
baffle tray is made horizontal.
4. The baffle tray tower of claim 2, in which curtain zone, the upper and
the lower edges of which are defined by the edge of the baffle tray at the
odd number stage and the edge of the adjacent baffle tray, is slanted with
respect to the longitudinal direction of the tower body.
5. The baffle tray tower of claim 2, in which the baffle tray is sloped
such that it is lowered toward the edge thereof from which the liquid
flows down.
6. The baffle tray tower of claim 2, in which the baffle trays at each of
the stages have a same shape, each of said baffle trays at the odd number
stages is disposed at the position just aligning with other baffle trays
at the odd number stages along the longitudinal direction at the tower
body, and each of said baffle trays at the even number stages is disposed
at a position just aligning with other baffle trays at the even number
stages along the longitudinal direction of the tower body.
7. The baffle tray tower of claim 1, in which at least one of the baffle
tray means at the odd number stage and the baffle tray means at the even
number stage comprises a plurality of baffle trays.
8. The baffle tray tower of claim 7, in which the baffle tray means at one
of the odd number stage and the even number stage comprises two baffle
trays, said two baffle trays have edges opposing to each other so as to
define a gap allowing the fluid to flow therethrough, the baffle tray
means at the other of the odd number stage and the even number stage
comprises one baffle tray, and said one baffle tray has two opposing edges
so as to form two gaps between the inner wall of the tray body for
allowing the fluid to flow therethrough.
9. The baffle tray tower of claim 7, in which the baffle tray means at one
of the odd number stage and the even number stage comprises three baffle
trays, said three baffle trays are disposed within the tray body so as to
define two gaps for allowing the fluid to flow therethrough, the baffle
tray means at the other of the odd number stage and the even number stage
comprises two baffle trays, and said two baffle stages are disposed within
the tray body so as to define three gaps for allowing the fluid to flow
therethrough.
10. The baffle tray tower in any one of claims 2-5, 7-9, 1 or 6 in which a
width for the curtain zone is made adjustable.
11. The baffle tray tower of claim 10, in which the width for the curtain
zone is adjusted by a curtain width control plate disposed within the
tower body.
12. The baffle tray tower in any one of claims 2-5, 7-9, 1 or 6 in which
the position for the upper edge and/or lower edge of the partition plate
in the longitudinal direction of the tower body is made adjustable so as
to adjust the height for the upper and/or lower curtain zone.
13. The baffle tray tower of claim 12, in which position for the partition
plate in the longitudinal direction of the tower main body is made
adjustable.
14. The baffle tray tower in any one of claims 2-5, 7-9, 1 or 6, in which
the tower body is of a cylindrical shape.
15. A baffle tray tower comprising:
(a) a baffle tray body extending vertically and having a top closure means
and a bottom closure means, said top closure means having a liquid inlet
and a gas exit therein and said bottom closure means having a gas inlet
and a liquid exit therein, said baffle tray body having a central
longitudinal plane extending along its axial length;
(b) a plurality of baffle trays mounted at spaced intervals in said baffle
tray body, each of said plurality of baffle trays extending from the
interior wall of said baffle tray body to said central longitudinal plane
and having an inner edge surface located in said central longitudinal
plane, alternate ones of said plurality of baffle trays extending from the
interior wall of said baffle tray body in opposite directions; and
(c) a plurality of at least generally planar partition plates mounted in
said baffle tray body, each of said at least generally planar partition
plates:
(i) having a central longitudinal plane which is coplanar with the central
longitudinal plane of said baffle tray body;
(ii) being spaced beneath a next higher adjacent one of said pluralty of
baffle trays so that a planar upper curtain zone is defined in said
central longitudinal plane between the lower, inner edge of said next
higher adjacent one of said plurality of baffle trays and the upper edge
of the generally planar partition plate; and
(iii) being spaced above a next lower adjacent one of said plurality of
baffle trays so that a planar lower curtain zone is defined in said
central longitudinal plane between the upper, inner edge of said next
lower adjacent one of said plurality of said baffle trays and the lower
edge of the generally planar partition plate, whereby, in use:
(d) liquid enters said baffle tray body through the liquid inlet in said
top closure means, flows downwardly from each one of said plurality of
baffle trays to the next lower one of said plurality of baffle trays
through one of said planar lower curtain zones, and exits said baffle tray
body through the liquid exit in said bottom closure means;
(e) gas enters said baffle tray body through the gas inlet in said bottom
closure means, flows upwardly from beneath each one of said plurality of
baffle trays to beneath the next higher one of said plurality of baffle
trays through one of said planar upper curtain zones, and exits said
baffle tray body through the gas exit in said top closure means; and
(f) the liquid and the gas flow through each other in counter-current
fashion as the liquid flows downwardly from each one of said plurality of
baffle trays to the next lower one of said plurality of baffle trays.
16. A baffle tray tower as recited in claim 15 wherein:
(a) said baffle tray body is cylindrical in shape;
(b) said baffle trays are at least generally semi-circular in shape; and
(c) said partition plates are at least generally rectangular in
cross-section perpendicular to said central longitudinal plane.
17. A baffle tray tower as recited in claim 15 wherein the upper surfaces
of said plurality of baffle trays are at least generally horizontal.
18. A baffle tray tower as recited in claim 15 wherein the upper surfaces
of said plurality of baffle trays are inclined downwardly towards their
inner edges.
19. A baffle tray tower comprising:
(a) a baffle tray body extending vertically and having a top closure means
and a bottom closure means, said top closure means having a liquid inlet
and a gas exit therein and said bottom closure means having a gas inlet
and a liquid exit therein, said baffle tray body having a central
longitudinal plane extending along its axial length;
(b) a plurality of baffle trays mounted at spaced intervals in said baffle
tray body, each of said plurality of baffle trays extending from the
interior wall of said baffle tray body to an inner edge surface located
adjacent to, but short of, said central longitudinal plane, alternate ones
of said plurality of baffle trays extending from the interior wall of said
baffle tray body in opposite directions; and
(c) a plurality of at least generally planar partition plates mounted in
said baffle tray body, each of said at least generally planar partition
plates:
(i) having an upper edge, a lower edge, and a central transverse axis which
is located in said central longitudinal plane;
(ii) being spaced beneath a next higher adjacent one of said plurality of
baffle trays so that a planar upper curtain zone is defined between the
lower, inner edge of said next higher adjacent one of said plurality of
baffle trays and the upper edge of the generally planar partition plate;
(iii) being spaced above a next lower adjacent one of said plurality of
said baffle trays so that a planar lower curtain zone is defined between
the upper, inner edge of said next lower adjacent one of said plurality of
baffle trays and the lower edge of the generally planar partition plate;
and
(iv) being disposed so that it cuts said central longitudinal plane, its
upper edge being on the side of said central longitudinal plane adjacent
said next higher adjacent one of said plurality of baffle trays and its
lower edge being on the side of said central longitudinal plane adjacent
said next lower one of said plurality of baffle trays, whereby, in use:
(d) liquid enters said baffle tray body through the liquid inlet in said
top closure means, flows downwardly from each one of said plurality of
baffle trays to the next lower one of said plurality of baffle trays
through one of said planar lower curtain zones, and exits said baffle tray
body through the liquid exit in said bottom closure means;
(e) gas enters said baffle tray body through the gas inlet in said bottom
closure means, flows upwardly from beneath each one of said plurality of
baffle trays to beneath the next higher one of said plurality of baffle
trays through one of said planar upper curtain zones, and exits said
baffle tray body through the gas exit in said top closure means; and
(f) the liquid and the gas flow through each other in counter-current
fashion as the liquid flows downwardly from each one of said plurality of
baffle trays to the next lower one of said plurality of baffle trays.
20. A baffle tray tower as recited in claim 19 wherein:
(a) said baffle tray body is cylindrical in shape;
(b) said baffle trays are at least generally semi-circular in shape; and
(c) said partition plates are at least generally rectangular in
cross-section perpendicular to said central longitudinal plane.
21. A baffle tray tower as recited in claim 19 wherein the upper surfaces
of said plurality of baffle trays are at least generally horizontal.
22. A baffle tray tower as recited in claim 19 wherein the upper surfaces
of said plurality of baffle trays are inclined downwardly towards their
inner edges. |
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Claims |
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Description |
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This invention concerns a baffle tray tower and, more specifically, it
relates to a baffle tray tower applied to the gas-liquid contacting
operation such as gas absorption or distillation.
Packed towers or tray towers have heretofore been employed as the
gas-liquid contacting device applied to the gas absorption, distillation
or the like.
However, the packed tower has a drawback of giving a difficulty in
scaling-up the tower since its operation efficiency is generally reduced
as the diameter of the tower increases although the efficiency is good
when the diameter of the tower is small, and in a necessity of determining
the required packing height experimentally. In view of the above, the use
of the packed tower with a large diameter is generally restricted only to
the case where the number of theoretical plates is relatively small.
While on the other hand, the plate tower or column has a demerit of
generally providing a great pressure loss although it can be used
conveniently based on the established scaling-up technique. Furthermore,
since the growth of polymer tends to occur on portions of the wall or the
like in the tower to which the liquid does not contact sufficiently, the
plate tower requires frequent maintainance when applied to the
rectification of easily polymerizable unsaturated compounds.
Further, in view of the structure in the conventional baffle tray tower
generally known so far, although the pressure loss can be reduced,
effective contact between the gas and the liquid is difficult to be
realized (low contact efficiency) since the gas stream passes through the
curtain zone between the adjacent stages of the baffle trays while being
spreaded over the entire zone. Therefore, the conventional baffle tray has
scarcely been employed for the gas absorption or distillation, being used
mainly for the heat transfer operation such as heating or cooling, dust
collection and the like.
In the conventional baffle tray tower, the contact efficiency or the tray
(plate) efficiency may be improved if the flow velocity of the gas is
increased in the curtain zone, which can be attained by decreasing the
interval between the baffle trays or reducing the tower diameter, but this
would result in an increase in the flow velocity in the window zone
leading to a greater pressure loss.
This invention has been accomplished in view of the foregoing problems and
an object thereof is to provide a gas-liquid contacting baffle tray tower
with a high gas-liquid contact efficiency and a low pressure loss.
According to this invention, the above-mentioned object can be attained by
a baffle tray tower comprising a tubular tower body, a plurality stages of
baffle tray means disposed within the tower body, and partition plates
each disposed within the tower body so as to divide a curtain zone defined
between two adjacent stages of the baffle tray means into an upper curtain
zone for mainly passing a gas therethrough and into a lower curtain zone
for mainly passing a liquid therethrough.
Another object of this invention is to provide a baffle tray capable of
distillation or absorption operation reliably and over a long time for
mixed liquid containing solid matters or easily polymerizable unsaturated
compounds.
This object can be attained in accordance with a baffle tray tower having
the foregoing constitution or, more preferably, with such a baffle tray
tower in which each of the above-mentioned baffle tray means has an upper
surface sloped such that the level of the tray means is lowered toward the
side of the window.
This invention is to be described in more details referring to the
accompanying drawings, by which the foregoing and other objects, as well
as the features of this invention will be made clearer in which
FIG. 1 is an illustrative perspective view for a baffle tray tower as a
first embodiment of this invention;
FIG. 2 is an illustrative transversing cross sectional view for the baffle
tray tower shown in FIG. 1;
FIG. 3 is an illustrative vertical cross sectional view taken along the
line III--III in FIG. 2;
FIG. 4 is an illustrative transversing cross sectional view for the baffle
tray tower as a second embodiment of this invention;
FIG. 5 is an illustrative cross sectional view taken along the line V--V in
FIG. 4;
FIG. 6 is an illustrative perspective view for a baffle tray tower as a
third embodiment of this invention;
FIG. 7 is an illustrative transversing cross sectional view for the baffle
tray tower shown in FIG. 6;
FIG. 8 is an illustrative vertical cross sectional view taken along the
line VIII--VIII in FIG. 7;
FIG. 9 is an illustrative perspective view for a baffle tray tower as a
fourth embodiment of this invention;
FIG. 10 is a partially broken illustrative transversing cross sectional
view for the baffle tray tower shown in FIG. 9;
FIG. 11 is an illustrative vertical cross sectional view taken along the
line XI--XI in FIG. 10; and
FIG. 12 is an illustrative perspective view for a baffle tray tower as a
fifth embodiment of this invention.
This invention will now be explained by way of a baffle tray tower 1 as the
first preferred embodiment referring to FIG. 1 through FIG. 3.
In FIG. 1 through FIG. 3, a cylindrical baffle tray body 2 is extended
vertically and has a liquid inlet 4 and a gas exit 5 at its top 3, as well
as a liquid exit 7 and a gas inlet 8 at its bottom 6.
Each of baffle trays 9, 10, 11, 12 and 13 as the baffle tray means is
formed with a semi-circular plate which is in close contact at the arcuate
edge thereof to the inner wall 14 of the tower body 2. The number of
plates for the baffle trays is determined depending on the application use
of the tower 1. Each of the baffle trays 9, 10, 11, 12 and 13 is disposed
substantially horizontally and arranged at an equal interval in the
vertical direction or the longitudinal direction of the tower body 2.
Among the trays 9 to 13 illustrated in FIG. 1, the third tray 11 and the
fifth tray 13 are situated just below the first tray 9, while the second
tray 10 and the fourth tray 12 are situated just below a first window 15
of a semi-circular space area defined by the first tray 9 and the inner
wall 14 of the tower main body 2. A third window 16 of a semi-circular
space area complementary to the horizontal shape of the third tray 11 and
a fifth window 17 of a semi-circular space area complementary to the
horizontal shape of the fifth tray 13 are situated just below the first
window 15, while a second window 18 of a semi-circular space area
complementary to the horizontal shape of the second tray 10 and a fourth
window 19 of a semi-circular space area complementary to the shape of the
fourth tray 12 are situated just below the first tray 9.
The number of baffle trays is properly selected depending on the kinds of
liquid and gas to be distillated or absorbed. The baffle trays at the odd
number stages and the windows complementary in the shape to the baffle
trays at the even number stages are of the substantially same shape and
situated at the positions just aligned vertically to each other. In the
same manner, the baffle trays at the even number stages and the windows
complementary in the shape to the baffle trays at the odd number stages
are of the substantially same shape and situated at the positions just
aligned vertically to each other.
Curtain width control plates 20 and 21 are extended vertically along the
inner wall 14 of the tower body 2 from the vicinity of the top 3 to the
vicinity of the bottom 6 of the tower. The curtain width control plates 20
and 21 define the horizontal length, that is, the width A of curtain zones
22, 23, 24 and 25, the respective upper and lower edges thereof being
defined with each pair of vertically adjacent trays 9, 10, trays 10, 11,
trays 11, 12 and trays 12, 13, as well as support the baffle trays 9, 10,
11, 12 and 13 at their linear edges 26, 27, 28, 29 and 30, respectively.
Partition plates 31, 32, 33 and 34 divide the curtain zones 22, 23, 24 and
25 respectively into upper curtain zones 35, 36, 37 and 38 and into lower
curtain zones 39, 40, 41 and 42, and the partition plates 31, 32, 33 and
34 transverse the vertical middle area of the curtain zones 22, 23, 24 and
25 and secured at both ends thereof to the curtain width control plates 20
and 21 respectively.
The partition plates 31 to 34 can eliminate the vertical middle zones in
each of the curtain zones 22 to 25 where the contact efficiency has
inevitably been lowered in the conventional baffle tray towers having no
such partition plates 31 to 34.
The term curtain zones 22, 23, 24 and 25 used in this specification means
those substantially or nearly vertical plane spaces, in which the upper
and lower edges of each of them are defined with one of the baffle trays
9, 10, 11 and 12 and the respective one of the baffle trays 10, 11, 12 and
13 situated one stage below the above-mentioned one of the baffle trays 9,
10, 11 and 12 so as to receive a liquid flowing down from the linear edges
26, 27, 28 and 29 of one of the higher baffle trays 9, 10, 11 and 12. Both
side edges of the curtain zones 22, 23, 24 and 25 are defined by the
curtain width control plates 20 and 21 and the area of the curtain zone is
defined as the maximum cross sectional area capable of passing
therethrough the gas and the liquid to be contacted.
The lower curtain zones 39, 40, 41 and 42 are those areas which mainly pass
the liquid. The area of each lower curtain zone, that is, the height B2
and the width A of the lower curtain zone is set to an appropriate size
depending on the flow rate of the liquid to be contacted. For varying the
curtain width A, the curtain width control plates 20 and 21 may be
replaced with other plates of different width. Alternatively, each of the
curtain width control plates 20 and 21 may, for example, be constituted
with at least two plate members partially overlapped in the lateral
direction with each other, and the relative position in the lateral
direction of these two plate members for each control plate 21 or 22 may
be changed by varying the laterally overlapping width for adjusting the
curtain width. Moreover, it may be constructed to adjust the width for the
upper curtain zone and the width for the lower curtain zone individually.
The upper curtain zones 35, 36, 37 and 38 are those areas which mainly pass
a gas therethrough. The height B1 or the area [(width A).times.(height
B1)] for the upper curtain zone is set to an appropriate size depending on
the flow rate of the gas to be contacted. Since a portion of the gas can
pass through the lower curtain zones 39, 40, 41 and 42 as well, the height
B2 or the area [(width A).times.(height B2)] for the lower curtain zone
may be also taken into the consideration in evaluating the flow rate of
the gas, and the effective area for the curtain zone [(width
A).times.(height B1+B2)] is set to an appropriate size as a whole.
Assuming that the width for the curtain zone is substantially defined, the
area for the upper and the lower curtain zones may be set appropriately by
adjusting the position for the upper and lower edges of the partition
plates 31, 32, 33 and 34, that is, the width i.e., height C and the
position for the partition plates 31 to 34 depending on the flow rate of
the gas. For changing the area of the upper and lower curtain zones, the
vertical mounting positions of the partition plates or curtain area
control plates 31, 32, 33 and 34 may be changed or the plates 31 to 34 may
be replaced with other plates of different width C. Alternatively, each of
the partition plates 31 to 34 may be constituted with at least two plate
members partially overlapping in their width direction (vertical
direction) and each of the width C for the partition plates 31 to 34 may
be changed by changing relative position of the two plate members in the
direction of their widths (by varying the overlapping width) to thereby
change the area for at least one of the upper and lower curtain zones.
As described above, the baffle tray tower 1, having the partition plates 31
to 34, can be operated efficiently over a wide operating range, for
example, from low to high production rate depending on the flow rate of
the gas and liquid.
The curtain width control plates 20, 21 may not be provided if the
partition plates 31, 32, 33 and 34 and the trays 9, 10, 11, 12, and 13 are
secured directly to the tower body 2.
In the case of the buffle tray tower where a number of baffle trays are
provided, the partition plates may not be provided in some of the curtain
zones.
In the baffle tray tower 1, the flow velocity of the gas or vapor passing
through the curtain zones is set usually at 2-10 m/sec in an atmospheric
pressure system and at 3-20 m/sec in a reduced pressure system, but it is
preferably set usually at 3-6 m/sec in the atmospheric pressure system and
at 3-15 m/sec in the reduced pressure system, in order to keep the
pressure loss low and the contact efficiency high.
In case of carrying out distillation under a reduced pressure in the baffle
tray tower 1 comprising a number of trays for example, it is preferred to
increase the height of the upper curtain zones 35, 36, etc. (that is,
increasing the upper curtain area) toward the top of the tower and to
decrease the height (that is, decreasing the upper curtain area) toward
the bottom of the tower. The height for the lower curtain zones 39, 40,
etc. may be different from each other as well. In this case, a highly
efficient operation is possible depending on the change in the ratio of
the flow rates of the gas and the liquid in the tower (from the top to the
bottom of the tower).
A similar partition plate 43 may be disposed as well between the lowermost
baffle tray 13 and the bottom 6 of the tower. In this case, the lower edge
of the partition plate may be below the liquid level at the bottom of the
tower.
The operation for the baffle tray tower 1 as the first embodiment according
to this invention having the foregoing constitution will now be explained
for a case where it is employed as an absorption tower.
A liquid introduced into the tower body 2 from the inlet 4 at the top 3 of
the tower flows down onto the uppermost baffle tray 9 and the liquid on
the tray 9 flows down from the edge 26 of the tray 9 through the window 15
onto the second tray 10 in the direction D in the form of a curtain-like
thin film, thread or droplet stream. The liquid on the tray 10 flows down
from the edge 27 of the tray 10 through the lower curtain zone 39 and the
window 18 onto the third baffle tray 11 in the direction E in the form of
the curtain-like thin film, thread or droplet stream. Then, the liquid
flows down in the same manner through the lower curtain zones 40, 41, 42
and the adjacent windows 16, 19 and 17 onto the trays 12 and 13 in the
direction D or E in the form of the curtain-like thin film, thread or
droplet stream and, finally, flows down from the tray 13 to the bottom 6
of the tower and is then recovered from the exit 7.
Each tray may have a plurality of fine parallel grooves extended to the
edge thereof on the upper surface of each tray so that the liquid may flow
uniformly over the entire width of the tray edge.
While on the other hand, a gas introduced into the tower body 2 from the
inlet 8 at the bottom 6 of the tower flows upwardly through the
semi-circular post space 44 below the tray 13, enters into the
semi-circular post space below the tray 12 passing through the curtain
zone 45 in the direction F where it is in contact with the liquid stream
in the direction D from the tray 13, passes through the window 17 while
turning its direction upwardly along the inner wall 14 of the tower body
2, flows upwardly in the space 46 and, thereafter, passes from the space
46 through the upper curtain zone 38 in the direction G into the
semi-circular post space 47 below the tray 11. The gas flowing in the
direction G into the space 47 is in contact with the liquid flowing down
in the direction E from the tray 12, passes upwardly in the space 47
through the window 19 while turning its direction upwardly along the inner
wall 14 of the tower main body 2, passes from the space 47 through the
upper curtain zone 37 in the direction F, contacts the liquid flowing down
in the direction D from the tray 11 and then reaches the window 16. The
gas having flown upwardly in the window 16 passes, in the same manner,
through the semi-circular post space 48 below the tray 10, the upper
curtain zone 36, the semi-circular post space 49 below the tray 9, the
upper curtain zone 35 and the semi-circular post space 50 above the tray
10 successively and, finally, reaches the top 3 of the tower and is then
sent out from the exit 5.
In the above process, gas-liquid contact is carried out between the liquid
stream flowing down from the lower curtain zone situated just above each
of the baffle trays in the direction D or E and the gas stream directly
after passing through the upper curtain zone situated just below the
baffle tray in the generally horizontal direction, that is, the direction
F or G.
In the baffle tray 1, since the gas is selectively passed mainly through
the upper curtain zones 35, 36, 37 and 38 by the presence of the partition
plates 31, 32, 33 and 34, the gas stream can surely be brought into
contact with the thin film-like liquid just after passing through the
lower curtain zones, as compared with the conventional baffle tray tower
without such partition plates when applied to gas-liquid contacting
devices. Specifically, the liquid stream and the gas stream are brought
into a close and concentrated contact at a comparatively high relative
speed in restricted gas-liquid contact regions 51, 52, 53, 54 and 55,
while the flow passage for the gas and the flow passage for the liquid are
separated by the baffle trays and the partition plates in the
semi-circular post spaces 46, 47, 48, 49 and 50 other than the contact
regions 51 to 55. Consequently, since the gas stream can be rapidly
separated from the liquid droplets after the contact in the course where
the gas flows from a gas-liquid contact region to the suceeding gas-liquid
contact region, a high gas-liquid contact efficiency can be obtained.
While on the other hand, in the baffle tray tower 1, since the gas flow
velocity in the region other than the restricted region near the upper
curtain zone is relatively low and the gas can flow slowly and smoothly
through the semi-circular post space, the pressure loss in the gas can be
kept lower.
The gas stream of a relatively high speed flux can be obtained by
appropriately defining not only the height B1 but also the width A of the
upper curtain zone. Specifically, the curtain width control plates 20 and
21 as well as the partition plates serve to gain the high speed flux of
the gas stream passing through the region where the high speed flux of
liquid is passed.
As described above, when the baffle tray tower 1 is applied as a reduced
pressure distillation tower, because of its low pressure loss as well as
high contact efficiency, the temperature at the bottom 6 of the tower can
be lowered to thereby reduce the degradation of the liquid staying at the
bottom 6, whereby heating by the steam at relatively low pressure and
relatively low temperature can be employed in the course of distillation.
On the other hand, in a case where the temperature at the bottom 6 of the
tower is unchanged, since the temperature at the top 3 of the tower may be
increased, inexpensive cooling water can be used for cooling distilled
vapors instead of providing low temperature refrigerated water for the
condenser at the top of the tower. Furthermore, since the contact
efficiency is high and the pressure loss is low in this baffle tray tower
1, distillation in a single tower can be expected in such a case where it
would otherwise be necessary to conduct the distillation by two towers in
series due to the restriction in view of the temperature at the top and
the bottom in the conventional tower.
In addition, since this baffle tray tower 1 produces less bubbles because
of its structure, different from the conventional plate tower, it can be
effectively applied even to easily bubbling liquid.
Furthermore, this baffle tray tower 1 is also suitable for the
rectification of mixed liquid containing solid matters or easily
polymerizable unsaturated compounds such as vinyl monomers.
The liquid in the form of the thin film or thread-like stream upon contact
with the gas stream flowing along the direction G in the gas-liquid
contact region, for example, the region 52, is scattered in the form of
droplets 56, collides against the inner wall 14 of the tower body 2 and
flows down along the inner wall 14 to the tray 11 while washing the inner
wall 14. That is, since the inner wall 14 of the baffle tray tower 1 is
always washed with the droplets containing a polymerization inhibitor, if
unsaturated compound is condensed on the inner wall 14, the condensed
droplets do not stay on the inner wall 14 for a long time, thereby
enabling to avoid the polymer formation on a inner wall 14.
Furthermore, since the baffle tray is flat causing no substantial liquid
hold-up on the surface thereof, the staying time of the liquid in the
tower is relatively short to reduce the possibility of the polymer
formation.
In addition, this baffle tray tower 1 has a simplified structure and can be
fabricated with a reduced cost.
FIG. 4 and FIG. 5 show a portion of a baffle tray tower 58 as the second
embodiment of this invention. In these figures, those components of a
baffle tower 58 of the same function and configuration as those in the
baffle tray tower 1 in the first embodiment carry the same or
corresponding reference numerals.
In the baffle tray tower 58 of the second embodiment, each of the baffle
trays 11a, 12a, 13a, etc. is disposed while slanted such that the height
or level for the upper surfaces 59, 60, 61, etc. is lowered toward the
curtain zone. Each of the trays 11a, 12a, 13a, etc. has a partially
elliptic shape corresponding to the slope of the upper surface so that the
linear edges 28a, 29a, 30a, etc. of the tray may be extended substantially
horizontally in the diametrical direction of the tower body 2. The
vertical cross sectional shape in FIG. 5 for each of the baffle trays 11a,
12a, 13a, etc. may be a wedged shape, instead of plate, so that the tray
thickness is reduced toward the edges 28a, 29a, 30a, etc. In this case,
the lower surface for each of the baffle trays 11a, 12a, 13a, etc. may be
horizontal.
This baffle tray tower 58 can operate as a gas-liquid contacting device
with a high contact efficiency and a low pressure loss in the same manner
as the baffle tray tower 1 of the first embodiment. Furthermore, in this
baffle tray tower 58, since the upper surfaces 59, 60, 61, etc. of the
baffle trays 11a, 12a, 13a, etc. are lowered toward the edges 28a, 29a,
30a, etc., solid matters if contained in the liquid can be rapidly
directed down along the slope to the bottom and discharged out of the
tower 58. Accordingly, in the case where the baffle tray tower 58 is
applied to the distillation of an easily polymerizable unsaturated
compound, if the polymer seeds are included in the liquid of the
unsaturated compound, the polymer seed or polymer can be rapidly flown
down to the bottom along the slope of the trays 11a, 12a, 13a, etc. and
discharged out of the tower body 2 before the polymer is formed or grown.
As described above, this baffle tray tower 58, when applied to the
distillation of the easily polymerizable unsaturated compound, can stably
operate as a distillation tower over a long time with less fear of the
polymer growth in the tower main body 2.
Furthermore, since there is little fear that the solid matters may remain
or deposit in the tower main body 2, this baffle tray tower 58 is also
suitable as a contacting device for liquid suspensions of polymer
particles or sludges.
In addition to its low pressure loss, since the amount and the time of the
liquid staying on the baffle tray are reduced in the baffle tray tower 58,
it is suitable also to the distillation of temperature-sensitive
materials, for example, those materials lacking in stability at high
temperature.
Furthermore, since the liquid can be drained satisfactorily or
substantially completely upon stopping of the tower operation and the
stationary operation can be attained shortly after the start of the
operation in this tower 58, the start and the stop for the operation can
be facilitated.
In the baffle tray tower 58, the slopes for the baffle trays may be
different at the upper and the lower portions of the tower 58, for
example, the slope may be increased for the baffle trays nearer to the
tower bottom.
The baffle tray means may comprise a plurality of baffle trays so that the
contact efficiency per unit volume can be improved in the baffle tray
tower.
FIG. 6 through FIG. 8 show a baffle tray tower 61 as the third preferred
embodiment of this invention, in which a baffle tray means 64 comprising
two baffle trays 62 and 63 of a same shape and a baffle tray means 66
comprising one baffle tray 65 are vertically disposed alternately.
The baffle trays 62 and 63 generally of a semi-circular plate shape are
arranged substantially within a horizontal plane so that their linear
edges 67 and 68 which are a little shorter than the diameter of the tower
body 2 are opposed in parallel with each other. The other baffle tray 65
each having two parallel linear edges 69 and 70 of an identical length and
two arcuate portions 71 and 72 in close contact with the inner wall of the
tower main body 2 is disposed substantially horizontally between the upper
and lower baffle trays means 64 so that the linear edges 69 and 70 are in
parallel with the linear edges 67 and 68 of the baffle trays 62 and 63.
The baffle trays 62 and 63 may be slanted such that the height or levels
of the upper surface thereof are lowered toward the respective edges 67
and 68, and the baffle tray 65 may have an upper surface formed by
connecting two planes slanted such that the height or level of the upper
surface of the tray 65 is lowered toward both of the linear edges 69 and
70.
Curtain width control plates 73, 74, 75 and 76 are disposed between the
baffle tray 62 and the baffle tray 65, while curtain width control plates
77, 78, 79 and 80 are disposed between the baffle tray 63 and the baffle
tray 65. The curtain width control plates 73 to 80 connect the baffle
trays 62, 63 and 65 securely. However, such curtain width control plates
73 to 80 may not be used in a case where the baffle trays 62, 63 and 65
are secured directly to the tower body 2.
Partition plates 81, 82, 83 and 84 are secured respectively at both ends
thereof to the curtain width control plates 73 to 80 and the partition
plates 81, 82, 83 and 84 divide the curtain zones 85, 86, 87 and 88
between the baffle tray means 64 and 66 into the upper curtain zones 89,
90, 91 and 92 and into the lower curtain zones 93, 94, 95 and 96
respectively.
In the baffle tray tower 61 of this third embodiment, two upper curtain
zones and two lower curtain zones are formed between the baffle tray means
64 and the baffle tray means 66, by which the gas and liquid streams are
brought into contact with each other in contact regions 97, 98, 99 and 100
and separated again after contact.
The width for the curtain width control plates 73, 74, 77 and 78 may be
made greater than the width for the curtain width control plates 75, 76,
79 and 80, so that the widths for the curtain zones 85, 86, 87 and 88 may
be identical. The tower body 2 may be made of a square tube or post member
having an inner space in the form of a quadrangular prism and the width
for the curtain zones 85, 86, 87 and 88 may be made of a same size.
FIG. 9 through FIG. 11 show a baffle tray tower 101 as the fourth
embodiment of this invention. In the baffle tray tower 101, a baffle tray
means 105 comprising three baffle trays 102, 103 and 104 and a baffle tray
means 108 comprising two baffle trays 106 and 107 of a same shape are
vertically disposed alternately.
The baffle trays 102 and 104 are of a same shape, and their linear edges
109 and 110 corresponding to chords of the circle are opposed in parallel
with parallel linear edges 111 and 112 of the baffle tray 103 by way of
gaps or windows 113 and 114 respectively.
The baffle trays 106 and 107 have linear edges 117 and 118 opposed to the
inner wall 14 of the tower body 2 by way of gaps or windows 115 and 116
respectively and linear edges 120 and 121 in parallel with the linear
edges 117 and 118 and opposed in parallel with each other by way of a gap
or window 119 respectively. While the baffle trays 102, 103, 104, 106, 107
are disposed horizontally in the illustrated embodiment, each of the tray
upper surface may be sloped or inclined such that the height or level of
their upper surfaces are lowered toward the linear edges 109, 110, 111,
112, 117, 118, 120 and 121.
Curtain width control plates 122, 123, 124 and 125 are disposed between the
baffle trays 102 and 106, in which the curtain width control plates 122
and 123 define the width for the curtain zone 126 and the width for the
passage of a liquid flowing down from the edge 109, while the curtain
width control plates 124 and 125 define the width for the curtain zone 127
and the width for the passage of the liquid flowing down from the edge
117. Curtain width control plates 128, 129, 130 and 131 are disposed
between the baffle trays 103 and 106, in which the curtain width control
plates 128 and 129 define the width for the curtain zone 132 and the width
for the passage of the liquid flowing down from the edge 111, while the
curtain width control plates 130 and 131 define the width for the curtain
zone 133 and the width for the passage of the liquid flowing do | | |
