Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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VAPOR/LIQUID CONTACT COLUMN STRUCTURE
Backq~ound_of the Invention:
The invention relates to columns such as fractional
distillation column structures and, more particularly,
provides an improved structure for increasing the
efficiency of vapor-and-liquid contact column operation.
The patent literature as relates to bubble plates or
contact devices, fractionation or rectification columns,
and so forth, is quite developed though no such
literature is currently known to the inventors which is
directly related to the subject invention as claimed.
The problem presently confronting the industry is one of
increasing efficiency of a column without incurring
substantial increases in fabrication and operating
costs. A hint of part of what can be done by changes in
internal design of columns is given in a paper generated
50 years ago at the Massachusetts Institute of
Technology entitled ~ectification~of Bin~y_~L~y~g~ by
W.K. Lewis, Jr., of that institution, publication date
at M.I nT~ April, 1936. At page 400 of such publication
there is il~ustrated the concept that, for stacked
bubble trays or contact devices, efficiency is enhanced
where liquid flow is in the same direction over each
tray. The publication, however, does not consider how
descending reflux liquid can be conducted other than in
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an enclosed downcomer diagonally through the space
directly between the plates; nor does it consider how
- the substantial vapor content in foam, of the descending
reflux liquids, can escape back into the primary vapor
- 5 path. Such vapor entrained in the reflux, of course,
defeats some of the suggested theoretical efficiency of
unidirectional reflux liquid flow over the contact
trays. Also, the downcomer causes a structural
obstruction in the contact chamber, further negating the
suggested theoretical efficiency of unidirectional flow.
For ease of discussion of the present invention, the
term "contact chamber" shall be used to describe the
inner chamher separating the vertically-spaced bubble
contact trays. The term "contact tray" or, generically,
"contact device", shall be used to identify any one of a
variety of trays used in, e.g., distillation towers and
columns which can be employed ln the present invention,
to-wit: sieve trays, valve trays, bubble cap trays, etc.
The term "downcomer" shall be used to describe the means
of conducting reflux liquid from one tray, or "contact
device", to the next lower tray. It shall also be used
to describe the space outside the contact chamber and
inside the column shell that serves for conducting
descending liquid in Ihe present invention. The term
"downcomer reservoir" shall be used to describe the
reflux pool held back in the downcomer for defoaming
prior to entering into the next lower contact chamber
prior to side draw cuts being taken.
Certain types of downcomer structures and tray designs
have been suggested by a number of authorities to
increase li~uid flow rates and to tend to minimize loss
of efficiency of vapor-and- liquid contact devices. See
examples cited in Chapter 16 entitled Fractionation and
Towers, Petroleum Refining Engineering, Fourth Edition
at pages 480-483 and in Chapter 6 entitled New
1 31 823~
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Fractionating-Tray Desi~ns, from the work "Advances in
Petroleum Refining and Chemistry", Volume I, at pages
277-334.
No means, since the publication date of these articles,
to the knowledge of the inventors, have been devised to
carry forward such germ ideas to the extent of the
present invention in devolving practical structure.
Also, nowhere in any literature, of which the inventors
are aware, is there disclosed any means or teaching
whatever of accomplishing unidirectional flow across
contact devices in a vertical column in a manner such
that descending reflux liquid does not interfere with
upwardly ascending vapors between contact trays; nor is
there indicated in the prior art, of which the inventors
are currently aware, of the teaching of using
rectangular contact tray areas in vertical columns for
maximum use of effective vapor-liquid contact, and also
the teachin~ of fabricating substantially identical
column sections of equivalent design, with each fitted
with custom-engineered, rectangular contact trays so
that the vertical columns herein may be made from
modules to fit a needed column or tower, engineering-
design profile. Furthermore, there is nothing in the
teachings in the prior art of the concept of providing
elongated ramp-type downcomer structures so as to create
essentially quiescent downcomer de-foaming reservoirs
prior to almost pure liquid introduction i.nto a next
succeeding contact chamber and onto its bubble tray.
This increases liquid throughput capacity, saves heat
energy, and reduces the need for side-stripper columns
and/or processes. In short, the above discussed
features and advantages makes the contact column of the
present invention more cost efficient.
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Su_marY o~ the Invention
In accordance with ~he present invention there is
provided a vertical column containing countercurrent reflux liquid
and vapors, including, ln combination, a rectangular, horizontal,
perforate vapor-and-liquid contact devlce having opposite ends;
conduit means of transverse rectangular cross-section in
correspondence with said contact device disposed above and secured
to said contact device for constraining and conducting vapors
emanating from said contact device upwardly, said conduit means
including a reflux-fluid inlet openlng adjacent one of said
opposite ends of said contact device and a weir opposite said
lnlet opening at the remaining one of sald ends ~or forming a
reflux-li~uid pool over said contact device, said conduit means
being provided a vapor-admittance side opening directly above said
weir; a downcomer structure exterior oi and secured to said
aonduit means and including a bottom portion adjacent to and
connected with said conduit means inlet opening, a top portion
positioned over said side opening, and a reflux-liquid slanted
downcomer ramp secured to and spiralling about said conduit means,
said downcomer ramp with said top portion beginning at a level
above said contact device and above said weir and made integral
with said bottom portion and said top portion; means for
conducting reflux liquid to said downcomer ramp via said ~op
portion; and a wall structure secured about said conduit means in
spaced relationship therewith and directly secured to said
downcomer structure and defining, with said downcomer structure
and said conduit means, a vapor-ascent space beneath said
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downcomer structure proximate said side opening of said conduit
means.
In accordance with the present invention there i5 also
provided a column section constructed for vertical stacking with
respect to similar sections, said section including, in
combination: a vertical conduit of transverse rectangular cross-
section and having upper and lower ends; a corresponding,
rectangular vapor-and-liquid horizontal contact davice secured to
said conduit transversely across said lower end and having an
inlet end and an exit end opposite each other, said conduit having
an inlet throat opening at and connected with said inlet end and a
gases' admittance and liquid discharge opening proximate and above
said contact device beneath said gases' admittance and liquid
discharge opening thereof; downcomer structure secured to and
outside of said conduit and having a lower end connected with said
throat, an upper end disposed above said discharge opening, and a
sloping ramp joining said lower and upper ends of said downcomer
structure; a wall structure disposed about said conduit and
secured to said downcomer structure and con~igured to form
therewith a countercurrent reflux li~uid and gases', 360
progressively redirected flow path between said wall structure and
said conduit; and structural means secured to said conduit
proximate said upper opening thereof for joining the conduit of a
corresponding external section to said conduit of said section.
In accordance with the present invention there is
further provided a vertically stacked column, with reflux liquid
froth, and ascending gases and vapors, said column including, in
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combination: plural, vertically stacked sections each including an
inner vertical conduit of transverse rectangular cross-section and
having upper and lower ends, an outer housing fixedly disposed
with respect to but spaced from and circumscribing said inner
conduit, strllcture securing the vertlcal inner conduits and the
outer housings of said sections in respective registration, said
conduits including horizontal, rectan0ular, vapor-and-liquid
contact devices positioned at and connected wlth their said lower
ends in registration ~herewith, respectively, said contact devices
having aligned inlet ends and side-opposite aligned exit ends the
latter beiny provided with respective weirs, said conduits having
vertically aligned liquid inlet mouths respectively registering
with said contact devicas' inlet ends and also vertically aligned
gases' exit openings respectively disposed above said weirs,
plural, downwardly sloping downcomer means disposed between and
secured to each conduit and its respective outer housing for
conducting reflux liquid overflow from the said weir of an upper
section along a 360 spiralled path to said inlet mouth of the
next lower section, said downcomer means also defining an upwardly
sloping ceiling partition for vapor flow resulting from the decay
of reflux liquid froth from that section next below, between its
conduit and outer housing, whereby to conduit said vapor flow
upwardly, exterior said central conduit, from the area of said
reflux liquid to the con~act device of the next higher section via
the said opening of said opening's associated conduit.
In accordance with the present invention there is
provided a stacked vertical column constructed for accommodating
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4c 61293-177
ascending vapors and gases and countercurrent descending reflux
liquid and froth, said column including, in combination: plural,
mutually-spaced, vertically aligned, rectangular, horizontal
vapor-and-liquid contact devices each provided with mutually
vertically aliyned outlet weirs, condui~ means of transverse
rectangular cross-section connected wlth said contact devices for
conducting vapor flow from one contact device to and through a
next-upper contact device, said conduit means having gases'
admittance wall apertures respectively disposed above said weirs
and reflux liquid admittance throats connec~ed to said contact
devices at ends thereof opposite said weirs; plural, vertically
spaced, spiralling, downwardly sloping downcomer means, laterally
disposed exterior of and secured to each of said conduit means,
for conducting overflow reflux liquid from each contact device to
the next lower contact device along a 360 path such that the
liquid flow across each of said contact devices is in the same
dixection, said downcomer means being constructed to direct,
countercurrent vapor and gases' flow as develops through reflux
liquid decay exterior of said conduit, over said descending reflux
liquid and into said conduit for progression upwardly through
progressively higher one of said contact devices.
In accordance with the present invention there is also
provided a column having countercurrent reflux liquid and vapors
and gases and including, in com~ination: a column section having a
vertical upward gas-and-vapor flow conduit of rectangular cross-
section; a horizontal, rectangular, vapor-and-liquid contact
device connected to said conduit and having liquid feed and liquid
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discharge ends, said conduit being provided with aperture means
providing reflux liquid ingress and egress relative to said
contact device; and structural means surrounding and affixed to
said conduit for creating with said conduit a reservoir pool of
reflux liquid above and at said aperture means operatively
associated with such ingress, whereby to permit progressively
bubble-decay and consequent degassing at a liquid level above said
ingress and thus allowing liquid, a~ a lower level of said
reservoir pool, for ingress to and over said contact device.
In acco.rdance with the present invention there is
further provided a column for ascending vapors, including, in
combination: a series of vertically-stacked sections mutually
secured together, feed inlet means provided said column, discharge
means provided sald column, and a series of removable,
rectangular, horizontal, vapor-and-liquid contact device means
mutually vertically superposed and respectively mounted in and
affixed to said sections and preselected, so as to provide for
desired inter-device vapor-pressure differential and desired vapor
flow rate.
In accordance with the present invention there is
provided a joined series of superposed, vertically stacked column
sections for accommodating countercurrent liquids and vapors, each
section including, in combination: inner and outer, concentric,
mutually-spaced conduits, said inner conduit having a transverse
rectanyular cross-section; a rectangular vapor-and-liquid contact
device horizontally disposed and mounted in said inner conduit;
liquid ingress and liquid-and-vapor egress means ~onnected with
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said contact device at opposite ends thereof; downcomer means
disposed between and secured to said inner and outer conduits and
connected with said ingress means; and plural means for
registering and securing other, exterior, upper and lower column
sections to said one section at said inner and outer conduits
thereof.
In accordance with the present invention there is also
provided a vertical column section for accommodating
countercurrent reflux liquid and vapors, comprising: a vertical,
rectangular conduit; a horizontal, rectangular, vapor-and-liquid
contact device connected with said ~onduit, said contact device
having a reflux liquid ingress end provided with a weir, said
conduit being provided with a throat connected with said ingress
end and a discharge openlng connected with said egress end; wall
enclosure structure surrounding said conduit; sloplng downcomer
structure secured to and between said conduit and said wall
enclosure structure, said downcomer structure having an upper end,
a lower end connected with said throat, and a ramp sloping from
said upper end downwardly to said lower end, said downcomer
structure comprising a baffle for isolating a space directly above
said downcomer structure from the space directly beneath said
downcomer, said conduit having a vapor admittance aperture,
forming an upper extension of said discharge opening, beneath said
downcomer structure and above said weir, for admitting ascending
vapors from between said conduit and said wall enclosure structure
into the space defined by and within said conduit, said upper end
of said downcomer structure being constructed to receive reflux
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4f 61293-177
liquid from the section next above, for allowing said reflux
liquid to flow downwardly toward said throat.
In accordance with the present invention there is
further provided a vertical column for accommodating counter
current descending reflux liquid and ascending vapors, said column
including, in combination: vertical conduit structure having a
transverse rectangular cross-section and provided with mutually
aligned and vertically spaced reflux liquid throat openings and,
side-opposite thereto, a series of mutually aligned and vertically
spaced vapor inlet openings, each o~ said vapor inlet openings
having upper portions disposed at respective horizontal levels
above corresponding ones of said throat openings; a series of
horizontal, rectangular, mutually-vertically-spaced, superposed
vapor-and-liquid contact devices, each having a reflux liquid
ingress end and a side-opposite re$1ux liquid egress end provided
a weix, secured to and within said conduit structure such that a
respective ingress end is contiguous with a respective throat
opening, and a corresponding weir of said egress end is connected
with a lower portion of said vapor inlet opening, said vapor inlet
openings of said conduit structure being constructed to provide
for reflux liquid egress from respective ones of said contact
devices; wall structure horizontally spaced from, secured ~o, and
surrounding said conduit structure; and plural downwardly sloping
downcomer structure disposed ~etween and ~ecured to said wall
structure and said conduit structure, representative ones of said
downcomer structures having lower portions contiguous with said
throat openings and upper portions disposed above corresponding
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ones of said vapor admittance openings, each of said upper
portions being secured beneath the respective, next~above vapor
openings for receiving a reflux liquid flow as occurs over the
weir of the respective next-above contact device, respective ones
of said downcomer structures downwardly curving about said conduit
whereby to provide 360 progressive-travel re-directional flow of
said reflux liquid as the same cascades ~or the egress opening of
the next-above contact devlce to the throat opening operatively
associated with ~he next-lower contact device.
The present invention provides, e.g., a fractionation
columnr distillery column, absorption column, etc, and sectors
thereof, comprising a series of ~enerally uniformly constructed
contact modules fitted with contact trays, pre-engineered for the
desired vapor capacity, that can be easily assembled one on top of
the other into a complete column prior to shipment to use site.
Fabrlcating columns of basically identical modules that contain
custom-engineered contact trays, as taught herein, results in
manufacturing costs being lower or at least comparable to present
column costs. The individual sections are desi~ned such that the
path of descending reflux liquid is outside of the ascending
primary vapor stream progressing through one contact tray upwardly
into the next contact chamber. Furthermore, elongated ramps are
provided within the downcomer structure so as to deter froth
and/or foam ~uildup choking the downcomer to the next lower
chamber. Also, a structure is provided for permitting ascending
secondary vapors evolving from the downcomer reflux reservoirs to
rise counter-current relative to the reflux liquid so as to ascent
1 3 1 8238
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into the contact chamber between vertically adjacent contact
trays, and to proceed with the primary vapor stream upwardly
through the next upper contact tray. The contact tray and the
contact chamber area between contact trays is maintained in an
unobstructed condition so as to maximize vaporflow efficiency.
Additionally, reflux liquld flows uniformly across the contact
trays in the same direction at all levels~ thus further enhancing
contact tray efficiency. Theoretical studies indicate a 15~ to
40% increase efficiency for unidirectional reflux liquid flow.
Tests have indicated that the present invention operates in a
manner superior to prior designs so far as capacity and operating
range are concerned. Column
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capacity to flood is materially extended. Liquid flow
rates over the exit weir of each contact device is
greatly improved. Tests have likewise indicated the
unique ability of the present still or column to operate
at wide ranges of liquid and vapor ratios with low
pressure drop.
The present invention may be utilized in petroleum
distillation, fractionation, alcohol distillation or
rectification, absorption, and indeed, wherever resort
is to be had, of in effect separating or combining
liquids and semi-liquid materials. It should be noted
that by the invention, engineering and capital costs of
construction as well as operating costs and heat energy
use are significantly reduced over prior art structures.
Accordingly, a principal object of the present invention
is to provide a new and improved`vapor-and-liquid
contact column and components thereof.
A further object is to provide a structure for a more
cost-efficient separation of various liquids, semi-
liquids, and gases into nearly pure fractional compounds
and for absorption of gases into liquids.
An additional object is to provide a downcomer structure
with an elongated sloping path and reservoir means for
reflux liquid to maximize defoaming, defrothing, and
degassing or reflux liquid.
An additional object is to provide ~or a reservoir in
the downcomer structure from which vapor-free reflux
liquid is introduced onto a next succeeding contact
tray.
An additional object is to provide a downcomer reservoir
from which essentially vapor-free liquid can be drawn as
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product, reducing the need for side cut stripper
columns, pumps, etc.
A further object is to provide a structure in columns of
S the type described which will conduct secondary vapor
generated by degasing of liquid in the downcomer, back
into the primary vapor flow within a contact chamber.
A further object is to provide a structure having a
series of vertically-spaced contact chambers which are
unimpeded by the downcomer reflux liquid carrying
structure.
An additional object is to provide in a column, a series
of vertically-spaced contact trays wherein reflux liquid
flow thereover is unidirectional.
An additional object is to provide means for
installation of custom engineered and designed contact
trays for desired vapor flow capacity to achieve optimum
pressure drop between successive chambers.
An additional object is to provi~e a contact column
whereby each vertically-spaced contact tray can have a
di~ferent vapor flow capacity and thereby make possible
for heat-removal from the top of the tower and by side-
cut products reducing the need for pump-around and
pump-back streams lower in the tower.
3Q An additional object is to provide a tower section
structure of essentially identical modular units which
can be stacked and secured together in a desired tower
column.
Brief Description of the Drawinas
The present invention may be understood by reference to
1 31 823~
the following detailed description, taken in connection
with the accompanying drawings in which:
Fig. 1 is a frontal perspective view of a column
incorporating the features of the present invention,
shown partially broken away, and illustrating two of the
several essentially similar sections of ~he column that
can be stacked and secured together.
Fig. 2 is a top plan of a representative one of the
column sections and is taken along line 2-2 in Fig. 1.
Fig. 3 is a front view of a pair of sections in the
structure of Fig. 1, broken away, and is taken along the
arrow 3 in Fig. 1.
Fig. 4 is a right side elevation, partially broken away,
and is taken along the line 4-4 in Fig. 1.
Fig. 5 is a left side elevation, partially broken away,
and is taken along the line 5-5 in E'ig. 1.
Fig. 6 is a rear view of the pair of sections
illustrated in the column of Fig. 1 and is taken along
the arrow 6 in Fig. 1.
Figs. 7, 8, and 9 are details taken along the arcuate
line 7-7 in Fig 6, illustrating a few of various forms
of construction that the individual bubble trays or
contact devices used may take.
Fig. 10 is an enlarged detail, principally in section,
and taken along the line 10-10 in Fig. 11, illustrating
adjustable gate and weir contructions.
Fig. 11 is a schematic drawing, similar to ~ig. 4, but
illustrates reflux liquid and vapors flows within a pair
1 3 1 8238
of joined sections of the column in Fig. 1.
Figs. 2-6 and 11 are shown in reduced scale.
Detailed Description
In Fig 1, column 10 is shown to comprise a multi-stage
device having a series of sections or modules 11 which
may be identical or substantially ~imilar in
construction and constructed to fit together in a
stacked relationship. Column 10 can include a heat
source 12 when that is desired as it would be in some
chemical and alcohol distillation processes. Any
modular section 11 can be fitted with a feed line inlet
13, a liquid draw line 13A or steam interjection line
13B, as illustr~ted in Figs. 1 and 11. The individual
sections 11 include a shell or wall enclosure structure
14 surrounding a vertical conduit comprising a conduit
structure 15A incluing a plurality of vertically stacked
chamber stages 15B.
Each of the chamber stages 15B is provided with
horizontal liquid-and-vapor "contact tray" 16 which
sometimes are also known as bubble trays or contact
devices. The contact trays provide a means for
developing a shallow pool 20, see Fig. 10, of reflux
liquid such that a bubbling vapor may pass upwardly
through such pool. Contact trays are installed such
that they can subsequently be removed and updated for
maintenance or custom-engineered changes in vapor flow
capacity. Thus, as seen in Figs. 7-9, the ontact
device or tray 16 may include perforations (sieve tray)
17 as seen in Fig. 7; the plates or trays 16 may also
include respective bubble caps 18 as in Fig. 8; or the
individual con'act tray 16 can be the Uniflex tray as in
Fig. 9. Such contact devices are sometimes known and
sometimes take the form known to those in the industry
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as sieve trays, bubble cap trays, Flexitrays, float
valve trays, and Uniflex trays. Suffice to say at this
juncture, as to operation, upwardly ascending vapors
within the individual contact chamber sections 11
proceed upwardly through the tray such that a portion of
the vapors will condense and enrich the progressively
upper reflux pools 20, successively, with lighter
fractions ascending from lower pools.
Again, the individual chamber stages 15B may be
identical in structure, rectangular in form, and be~
secured together b~ suitable straps 22, see Figs. ~ and
5. It is important to note that a panel 23 of each
chamber or stage 15B includes a lower gate opening or
throat 24, see Figs. 3 and 1~, for the admittance of
reflux liquid onto the corresponding contact tray 16.
Correspondingly, and at the other end of the contact
tray 16 for each stage or section 15B, there will be
disposed an exit weir 25 and, thereabove a rear opening
26 in such contact chamber 15B. Successive chambers 15B
form the conduit structure 15A for ascending vapors. A
downcomer structure 27 is disposed outside the area of
the contact chambers 15B, i.e., outside of but affixed
to the conduit structure 15A. Each downcomer structure
27 includes an upper portion 28 and a lower hori20ntal
portion 29, interconnected by two, declining ramps 30
and 31. If desired, a single declining ramp 30, 31 need
be employed; in such event the remaining side may be
simply closed.
In any event, and in the embodiment shown, the downcomer
structure receives reflux liquid which gradually
descends into reflux reservoir 20A along ramps 30 and 31
to horizonta~ portion 29. The reflux liquid enters the
opening or gate 24 to form a pool 20 over the associated
contact plate 16. The pool depth can be defined by the
inclusion and setting of the weir 25. Accordingly, and
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in operation, reflux liquids descend downwardly along
the downcomer structure 27 then proceed unidirectionally
over the contact trays 16 by virtue of the reflux pools
20 formed relative to weir 25. The reflux liquid
overflows the upper edge of weir 25 and through side
opening 26; such reflux liquids will descend into the
upper position 28 of a next lower downcomer structure 27
via the ramps 30,31.
Fig 10 illustrates that attachments 32 may be employed
to secure the contact devices within their several
sections to accommodating brackets 33. These may be
included such that the contact trays can be removed when
desiredl as from the top. Also, Fig. 10 illustrates
that opening 24 in Fig. 1, for example, may be formed by
an adjustable gate 34, see Fig. 10, that is hinged at 35
to the primary structure and moved by a control 34A.
This is for the purpose of selectively increasing the
depth of the downcomer reflux liquid, as at reservoir
20A, and thus increase the pressure of such liquid,
whereby to introduce liquid uniformly into the contact
chambers; reflux liquid depth in the downcomer reservoir
will allow for gradation or zoning of the liquid, i.e.,
from some dense low-level liquid which is essentially
gas-free to upper low density liquid levels where gas
bubbles are substantially prevalent and susceptible to
decay.
Fig. 11 is in schematic form and illustrates the flow of
the reflux liquid, the vapors within chamber sections
l5B, and also the vapors that ascend from the liquid in
the reflux reservoir 20A of the downcomer structure 27.
In the latter case, the downcomer structure provides a
gradual settling in of descending reflux liquid into the
reflux reservoir proximate opening 24. This in essence
forms a generally quiescent zone prior to reaching the
mouth of 24 above horizontal portion 29. It is
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essential that the still or column be operated such that
the reflux reservoir 20A level is above the lip defining
the top or opening 24, thereby forming a liquid seal and
keeping any foam or froth above such reflux liquid. The
collapsing of bubbles will produce vapors that will be
free to go countercurrent to the reflux liquid, prior to
the gradually descending reflux li~uid, entering opening
24 and the vapor ascending back into one of the conkact
chambers 15B, then through the associated contact tray
16 into the contact chamber 15B thereabove. A feed Iine
13, draw-line 13A, steam injection line 13B are also
included. Stea~-injection may be employed at 13B to
lower vapor pressure, at selected still levels, to
enchance vaporization.
To be noted is the fact that optimum plate area is
employed for vapor-and-liquid contact and to maintain
constant liquid flow velocity and to reduce transverse
hydraulic gradient across the tray 16; also, inter-plate
space is unobstructed ~nd unidirectional flow across the
several plates is achieved. Fig. 11 illustrates in
detail the reflux liquid and countercurrent vapor flo~.
Heat can be supplied if needed by a heat source 12, as
illustrated in Fig. 1. Bottoms are drawn off and
separately processed as indicated at 36. Non-condensed
gas and vapors are drawn off at 37 and fed to condensing
units and a portion of which is fed back to the column
at the top plate thereof as reflux liquid. The column
may be made of any number of modules 11 as shown; each
module i5 engineered for the sections to be easily
fitted together and seam-welded or otherwise connected
at 38. The regulation of pressure between individual
contact module~ may be had by custom-engineered contact
trays for optimum pressure drop and contact efficiency.
The individual sections are constructed such that the
1 31 82~8
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upper portion 28 of a respective downcomer structure 27
is positioned below the horizontal level of contact
plate 16 from which the reflux liquid is descending,
this so that there will be a desired dropping of reflux
liquid as the same overflows the weir and descends in
the downcomer structure 27. The elongation and slanted
nature of the downcomer ramps 30,31 of each section
serves to minimize gas entrainment, frothing and
foaming, relative to the relatively gas-free reflux
li~uid that descends and gathers at the next lower
contact chamber at opening 24. This greatly improves
the operating efficiency of each contact device. It is
noted that reflux flow and defrothing is kept totally
outside of the area of the contact chamber of each
module appertaining thereto. Further, contact chamber
area is unimpeded by a structure carrying reflux liquid
to a next lower chamber. In the invention shown, the
reflux liquid path as to its descent through the column
is maintained outside of conduit structure 15A. Thus,
efficiency is further enhanced as to each section and
the combined column.
Finally, it is seen that the downcomer structure 27 is
arranged such that over-plate liquid proceeds across
each contact device in the same direction, i.e., from
left to right as per Fig 4. This further increases
efficiency of the column as explained hereinbefore.
.
What is provided therefore is a new and useful
construction for separation or combining ~absorption) of
vapors, liquids, fractions, etc., through the employment
of contact devices for maximum contact of descending
reflux liquid and ascending vapors. Provision is made
for minimizi'ng inefficiencies, and for omitting
downcomer structure directly above and beneath the
contact devices, so as to maximize efficiency of use of
such contact devices. Likewise, provision is made ~or
1 31 8238
upward ascent of secondary vapors and gases escaping
from the reflux liquid outside of the contact chamber,
so that such may be reintroduced, beneath the next upper
contact device.
Accordingly, the present invention provides a vertical
conduit comprising a conduit structure 15A including a
plurality of vertically stacked conduit chamber stages
15B. In a preferred embodiment, each of the conduit
chamber stages 15B is of a transverse rectangular
crcss-section and mounts a rectangular vapor-and-liquid
contact tray or device 16, see Figs. 1 and 11. The
conduit structure 15A is arranged to be in
correspondence with ~he contact devices for constraining
and conducting vapors emanating from each contact device
16 upwardly. In the structure, the reflux-liquid,
slanted downcomer ramps 30, 31 are secured to and
spiral, and thus are found spiralling about the conduit
structure 15A. The reflux-liqu.id flow is unidirectional
over all of the vapor-and-liquid contact devices 16 due
to the configuration of the downcomer structure 27,
Indeed, pursuant to the invention, the reflux-liquid
path defined by the arrangement and configuration of the
wall structure 14, conduit structure 15A, contact
devices 16 and the downcomer structure 27 spirals 360
between adjacent, vertically aligned openings 24 of the
contact devices 16, as seen in Figs. 1, 6 and 11. The
downcomer ramps 30, 31, with the wall enclosure 14, thus
effectively form a countercurrent reflux liquid and
gases', 360 progressively redirected flow path about
the c~nduit structure 15A, i.e., a 360 spiralled path,
spiralling from one contact device 16 to the contact
device 16 next below.
While particular embodiments of the present invention
have been shown and described, it will be apparent to
those skilled in the art that changes and modifications
1 3 1 823~
-14-
may be made without departing from the invention in its
broader aspects, and, therefore, reference should be
made to the appended claims, in determining the true
spirit and scope of the invention.
