JPS60175536A - Ultra-low flow amount liquid distribution apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to gas-liquid contact towers where intimate contact between gas and liquid is required to exchange the properties of the gas and liquid or to mutually change the states of the gas and liquid. Regarding the equipment used. More particularly, the apparatus relates to an apparatus for directing liquid downwardly in such columns at very low flow rates and in a very uniform distribution pattern.

In industrial processes where liquid and vapor are present together in a tower or column, it is necessary to add liquid to the process taking place inside the column or to condense the vapor as it rises through the column. There are many instances where it is desirable to flow downward through vapor to effect mass or heat transfer between the liquid and gas phases. In other cases, a liquid containing an inhibitor is fed to the column at a predetermined height to prevent or suppress undesirable events or processes from occurring. An example of the purpose of supplying an inhibitor to a column is to prevent polymerization of reactants and/or products in the column or packed column. Often such inhibitors are fed to the column along with the recycled gas and liquid.

In any case, it is best to distribute this liquid feed into the gas or vapor as closely as possible in order to achieve the homogeneity of the gas-liquid mixture necessary for close control of the process proceeding in the column. much desired.

Column packings are commonly used therein to help achieve more uniform mixing of the gas and liquid phases in the column.

Furthermore, in order to achieve better mixing in the column packing, the liquid fed into the column packing from above is often first fed through a mechanical device such as a distributor. The distributor uses a variety of means to separate the downwardly supplied liquid into smaller spread streams with a substantially uniform separation pattern therebetween. It is desirable to have these streams flow at substantially the same flow rate.

Many efforts have been made in the past to increase the efficiency of such liquid distributors. For example, U.S. Pat.
, No. 446゜489, No. 3,360,246, No. 3,937,769, No. 3,273,872, No. 3,143,581, No. 3,612.494 ,
Same No. 3,916,021, No. 3,392,967, No. 3,259,380, No. 3,006,623
No. 4,267.978 and No. 4,126.
No. 540, as well as British Patent No. 1,364,649. 1, please also refer to the following commercial catalog: (1) ” 1”rnuer Packing
Arrd Interluxls” (1975), Buretin A217. 2nd edition, pp. 10-20, published by G11t8ch, Inc., Dallas, Texas, USA.
'2) @Packed TcnoerJnt ern
txl s'' (1976), Buretin TA-8O
R, pp. 3.0-5.1, N. Akron, Ohio, USA.
Published by orton Com%n'jl.

Much of the information and equipment described in these publications is directed to improving the distribution of liquids in gas-liquid contact columns.

Nevertheless, achieving and maintaining uniform liquid distribution remains a vexing problem in industrial applications. Approximately 32.5 to 32.5 to
40.7t1min/i (0.8~1.0gal/min/ft
2) This is especially true when dealing with very low flow rate liquid dispensing, such as lower flow rates. One of the constant problems with these dispensers is blockage of the liquid distribution outlet by debris contained in the liquid. Of course, when an outlet begins to become occluded, the flow rate from the remaining open outlet changes and liquid misdistribution is an attendant undesirable consequence. Another factor contributing to liquid misdistribution is the presence of a vapor or gas phase within the liquid phase. Yet another well-known problem often encountered in plate or trough type distributors is imperfect horizontal alignment caused initially or subsequently by shifting of the tower during tower construction.

It would be advantageous to have a distributor that has much less trouble with debris in the liquid, vapor in the liquid, and misdistribution caused by very low flow rates. These and other advantages are achieved by the present invention.

The invention provides that the feed to a liquid distributor includes at least some incidental solid debris of a different density than the liquid, and that the liquid to be dispensed by the distributor extends over a virtual horizontal plane directly below the distributor by a unit area of the horizontal plane. A device for dispensing liquid in a vertical gas-liquid contacting column that is required to be distributed in a substantially uniform pattern across the liquid at a flow rate of less than 32.5 t1 min/i (0.8 gal/min/ft2), The dispensing device includes a series of substantially horizontally spaced closed distribution tubes, a transfer tube for maintaining the distribution tubes in fluid communication with each other, and a pressurized connection to the series of distribution tubes. and a plurality of substantially vertically spaced small tubes inserted into the bottom of the series of distribution tubes; The tubing has a sealing fit at the bottom and extends into this tubing a sufficient distance to prevent blockage by solid debris at the bottom of the tubing, but blockage may occur due to floating solid debris at the top of the liquid in the tubing. The tubes do not extend far enough to the top of the distribution tubes to extend far enough, and the bottoms of these tubes are spaced apart from each other so that the towers directly below the lower ends of these tubes in the tower do not extend far enough to the top of the distribution tubes to A liquid distribution apparatus is provided that is adapted to produce at least a substantially uniform pattern of distribution of liquid in a column across a virtual horizontal plane.

The present invention relates to a liquid distributor in a vertical gas-liquid contact column. The distributor distributes a feed having a liquid phase that has a different density than the liquid phase of the feed and at least incidentally contains some solid debris that either floats on top of the liquid or settles to the bottom of the liquid. It is designed to allow you to

Furthermore, this dispersion device can dissipate liquid at a rate of approximately 32.5 t/min/n?
It is designed to dispense at flow rates less than (0.8 gallons/minute/ft2). The area of the column in this case is measured with reference to an imaginary horizontal plane in the column directly below the distributor outlet (this plane is limited by the interior of the wall forming the column).

In addition to low flow rates, the distributor of the present invention is designed to allow a greater number of liquid distribution points per unit area of horizontal column cross section than is normally used. Typically, liquid distributors with no more than about one distribution point per 161i (251n2) of horizontal column cross section are used commercially. However, the need to provide distributors with a greater number of distribution points per unit horizontal cross-sectional area of the column has long been avoided. One of the major obstacles to going to such large numbers has been the problem of blockage of the distribution point by debris in doing so. This is because the larger the number of dispersion points per unit area, the smaller the size of the opening for a given flow rate must be. Of course, the smaller the aperture size #1, the more susceptible those apertures are to contamination and blockage by debris. Furthermore, the greater the occlusion of the aperture, the greater the maldistribution of liquid. This increased misdistribution, of course, defeats the purpose of increasing the number of distribution points per horizontal unit area of the column.

The distributor of the present invention provides a means for achieving a greater number of distribution points per unit area while substantially avoiding the increased clogging of these distribution points described above. This distributor accomplishes the above described means simply by using a distribution point of the distributor which is adapted to remove liquid from the distributor at a point substantially free of debris. That is, the inlets to these distribution points are not located at the top of the liquid level in the distributor, where lighter debris is suspended, nor at the bottom of the liquid level, where heavier debris is deposited.

Rather, these inlets are located at a point between the top and bottom of this liquid level where such debris is substantially absent.

By so locating the dispensing point inlet into the disperser liquid, the disperser of the present invention avoids the dispensing point blockages and liquid spoilage previously encountered when attempting to achieve this large dispensing point concentration. Much larger distribution point concentrations than normally achievable can be achieved without the occurrence of distribution. According to the present invention, the distribution point concentration can be easily increased so that there is at least one distribution point concentration per column cross section 129i (20 in2). In fact, the distribution point concentration is preferably as low as 6 so that there is at least one distribution point per 97 cJ (15 in2) of column cross-section without appreciable blockage.
It can be increased so that there is at least one distribution point per 10 in2.

Moreover, this large distribution point concentration is 932.5 t1 min/d (0.8 gal/min/ft2 per unit area of column cross section).
), preferably less than 20.35 t1 min/crIl (
0.5 gallons/minute/ft2), more preferably less than 8
．． Flow rates of less than 141.7 minutes/i (0.2 gallons/minute/ft2) can be achieved in uniform patterns over long periods of time. Furthermore, these liquids can be very uniformly distributed over long periods of time at these very low flow rates in combination with the high concentration (and necessarily small size) distribution points described above.

The distributor of the present invention essentially comprises (1) a series of substantially horizontally spaced distribution tubes and (2) a transfer line for maintaining the distribution tubes in fluid communication with each other. (3)
(4) a pressurized liquid supply device for supplying liquid to the series of distribution pipes at a pressure greater than the tower pressure outside the series of distribution pipes; and a plurality of substantially vertically spaced hollow tubules extending downwardly from the individual tubes of the distribution tube group.

The six tubes in the series of distribution pipes are hollow and sealed except for the transfer lines, liquid supply devices, and sump openings that provide connection points for the small tube series, and the liquid inside these distribution pipes is transferred to the series of distribution pipes. It is possible to maintain a higher pressure, preferably a constant higher pressure, than in the drywall immediately outside the pipe group.

A liquid supply device is capable of delivering liquid at a constant flow rate and at a constant pressure to a series of distribution pipes.

The tubules are arranged vertically and are sealingly fitted to the bottoms of the horizontal tubes of the series of distribution tubes. This group of tubules serves as the distribution point mentioned above.

These extend into the distribution tubes long enough to prevent placing the inlet openings of the distribution tubes in the lower layer or bottom of the liquid where debris heavier than the liquid will settle, but debris lighter than the liquid does not extend far enough into the distribution tube to place the inlet opening of the distribution tube group above the liquid in the tube where it settles.

The dimensions of the tubule groups are the same. That is, the length of the canalicular group insofar as it is desired that the flow rate of liquid through each of these canalicular groups is the same, and insofar as such flow rate is proportional to its internal cross-sectional area and inversely proportional to its length. are the same and their inner diameters are the same. These dimensions are of course determined by the total flow rate desired to come from the total number of tubes, and the total number of tubes is proportional to the dimensions of the tower and the concentration of tubes per unit area of the horizontal section of the tower. do. Since a uniform flow distribution pattern is desired from the outlet of the tube group, the number of tubes along a distribution tube must be such that these tubes form a more uniform pattern across all the tubes in the series. Therefore, it is limited by the distance from one distribution pipe to an adjacent distribution pipe. Another consideration in determining flow rate is the pressure drop caused by the liquid flowing through the tubules. That is, the distance between the distribution tube and the canalicular group, the number of canalicular groups, the dimensions of the holes in the canalicular group, the length of the canalicular group,
and the pressure drop of the liquid flowing through the tubules must all be adjusted to obtain the desired flow rate from the distributor of the present invention.

However, the central idea remains, and that idea is to maintain a sufficient pressure drop across the tubules so that the distribution pipe has enough liquid so that the pipes within the pipe The inlet opening of the tube should not be immersed in the liquid up to the middle stream of the distribution pipe to the bottom of the distribution pipe, which could cause blockage of the tube group. This greatly reduces the risk of occlusion, and the canalicule group can greatly reduce the internal opening size, allowing the canaliculi to form without occlusion.
This makes it possible to reduce the actual flow, making it possible to arrange more tubules per unit area and thus allowing for better uniformity of liquid distribution.

Further combinations of parts make the invention described above even more versatile. By adding a sufficiently long open top end storage vessel to the above arrangement at a given height above the series of distribution pipes, the liquid feed can now be fed into this storage vessel instead of directly feeding the series of distribution pipes. and the storage vessel is connected to and in fluid communication with a conduit descending from thence to a series of distribution tubes, then the liquid distribution device consists of a liquid phase and a gas phase. The present invention provides a multiphase ultra-low flow liquid distributor that can uniformly distribute the liquid phase of the feed into the column at ultra-low flow rates in a simple manner.

Industry has needed such equipment for a long time.

The invention will be better understood by reference to the accompanying drawings. Similar parts have the same reference numerals in these drawings.

FIG. 1 is an elevational cross-sectional view of a column housing the multiphase ultra-low flow liquid distribution device of the present invention.

2 is a top plan view of the apparatus of FIG. 1 taken along line 2--2 of FIG. 1; FIG.

FIG. 3 is an isometric drawing of the liquid dispensing device of FIGS. 1 and 2;

FIG. 4 is an enlarged, fractured side view of one of the distribution tubes with one of the groups of tubules located in the distribution tube indicated by the circled area FIG. 4 in FIG.

FIG. 5 is an isometric drawing of another embodiment of the dispensing device.

FIG. 6 is a bottom view of the dispensing device of FIGS. 3 and 5. FIG.

One embodiment of the present invention that is capable of handling feeds consisting of both gas and liquid phases is shown in Sections 1 and 4 South and in FIG. An example in which there is no need to deal with the gas phase in the feed is shown in FIG. Many features of the second embodiment are also shown in the first embodiment. This is because both concrete examples have many characteristics in common.

Referring to FIG. 1, the multiphase ultra-low flow liquid distribution system 10 of the present invention may be installed in a typical column 12 that includes a bed 14 of column packings. In this column, liquid from distributor 10 is intimately mixed with vapor rising in column 12 from below packed bed 14. Liquid distribution device 10 is connected to column 12 by supports 16 welded around the interior of the vertical cylindrical side wall of column 12.
supported inside.

The distributor 10 includes a storage tank 18, a series of distribution pipes 20, and a distribution pipe 2o.
a conduit 22 forming a fluid communication connection between the reservoir 18 and the reservoir 18;
, and a group of liquid distribution small tubes 2 extending downward from the distribution pipe 20.
Has 4.

Transfer tubes 21 interconnect the distribution tubes 20 to provide fluid communication and pressure transfer connections between the tube groups of the distribution tubes 20.

Reservoir 18 is designed to be sufficiently large to maintain the gas-liquid mixture supplied to reservoir 18 from inlet conduit 28 in a substantially stationary state. This is done in order to separate the gas phase from the liquid phase of the feed and pass it through the open top of the reservoir 18 into the interior of the column.

To prevent solid debris in the incoming feed from entering conduit 22, distribution pipe 20, and tube group 24 and occluding the tubes, reservoir 18 has two features.

The first of these features is the screen 3o through which the feed from the inlet conduit 28 must pass before it can reach the top of the conduit 22.

The second feature 9 places the opening of the conduit 22 at a sufficient distance above the bottom of the reservoir 18 so that debris heavier than the liquid settles from the liquid to the bottom of the reservoir 18 before the liquid flows into the opening of the conduit 22. This is a combination made like this.

To further facilitate the installation of the reservoir 18 through the column opening, the feed pipe 28 has a breakaway coupling 31 on the side of the reservoir 18 and the conduit 22 connects the bottom of the reservoir 18 with the distribution pipe 2.
It has a breakaway cup 1 lug 32 between it and the top of the o. Similarly, the series of distribution pipes 2° has breakaway flanges 33 to separate the distribution pipe group into two different sections ν to facilitate installation in the column.

The conduit 22 is fixed at a certain height above the distribution tube 20 so as to provide a constant liquid head pressure to the liquid in the distribution tube 20. In this manner, slight variations in the heights of the distribution tubes 2o relative to each other do not have as great an effect on the distribution of the flow from the distribution tubes as they do in conventional plate and trough type distributors. (See U.S. Pat. No. 3,446,489 for an example of a grate-type distributor; U.S. Pat. No. 3,392,967 and 3,937,76 for an example of a trough-type distributor.
Please refer to No. 9. ) The series of distribution pipes 20 are formed from a number of closely spaced horizontally arranged parallel closed pipes which are interconnected by transfer pipes 21 so that they are all at substantially the same height in the column. It is connected to the. Therefore, the pressure of the liquid inside each of the distribution pipe 2o and the transfer pipe 21 is
The liquid that can pass through o and 21 is conduit 2.
When the conduit 22 experiences no appreciable pressure drop compared to the constant head pressure provided by the liquid in the conduit 22.
is substantially the same as the liquid head pressure at the bottom of the

A large number of vertical, spaced small tube groups 24 form the distribution pipe 20.
Screwed into the bottom of the set of screws. The top of the small tube group 24 is between the top and bottom of the distribution pipe 20! It extends an intermediate distance to prevent debris remaining in the liquid from entering the openings of the canaliculi and clogging them. This is because substantially all of the debris is either suspended near the top of the distribution tube 20 or is deposited at the bottom in the distribution 920, away from the intermediate flow. Canalicular group 24
The number of tubes, their internal diameters and their lengths are adjusted according to the spacing of the distribution pipes and the height of the conduit 22 to achieve the desired flow rate out of the distributor 10.

Another example of this distributor is shown in FIG. This is the case when there is no gas present in the feed and a constant pressure is applied to the liquid in the distribution pipe 20 by means other than the liquid head pressure provided by the liquid level in the conduit 22 of the first embodiment described above. It is designed for. This further embodiment 11 is supplied at any point entering the series of distribution pipes 20. A horizontal feed pipe coupling 34 is provided here.

Referring to FIG. 6, the square uniform distribution of the tubelets 24 is illustrated by the dashed lines 40 connecting the tubelets 24.

EXAMPLE A liquid distributor similar to that shown in FIGS.
4 inch) packed column. Each of the parallel distribution pipes 20 had a 2.54 crn x 2.54 (1 inch x 1 inch) square vertical cross section.

There were a total of 7 distribution pipes spaced 10 crn (4 inches) apart. Conduit 22 had a diameter of 1.27 cTnuA inches) and a total length of 30.5 (771 (12 inches)). Reservoir 18 was 30.5 rfn long x 30.5 crn wide.
It was 10 cm tall (12 inches long x 12 inches wide x 4 inches high). The top of storage tank 18 was open. The conduit 22 was extended from the bottom of the storage tank 18 a distance of about 1.27 m (V2 inches) above the bottom of the storage tank 18.

A group of small tubes 24 extended into these tubes 20 a distance of approximately 1.27 cTn (V2 inches) from the bottom of the distribution tube 20. Each of these tubule groups is 20.3 crn (8
inch) and the inner diameter is 0.14 rrn (0,055 inch)
Met.

Forty-nine tubules were used and these were spaced in the same distribution pattern as shown in FIG. This is 10Cr
It is a square pattern of n x 10 (-In (4 inches x 4 inches). The concentration of the small tube group is 64.5 in the plane cross section of the virtual tower.
tr! There was approximately one tubule per (10in2).

3. Feed from inlet conduit 28 to storage tank 18; Ot1 minute (0
, 80 gallons/minute) for approximately eight months.

The feed consisted of a liquid phase and a gas phase, with a ratio of about 90 volumes of liquid phase to about 10 volumes of gas phase. The gases in the gas phase are mainly acrolein, formaldehyde, and inerts. -4-1-
1i11f1-'IP)yIIn,tMbh-)r(M
There was one τFA-ysf. The feed also contains an inhibitor which incidentally reacts with impurities to produce solid debris that is deposited in the bottom of the reservoir 18 and the screen 3.
It accumulated to 0. Column light beam 1 from the bottom of the canalicular group 24
The flow rate to 4 is only 10 in the cross section of the tower: l/min C
0.25 gallons/minute per square foot). The flow rate from each tube 24 was 0.06 tons/minute (0.016 gallons/1). The tower was able to operate consistently for five months without any blockages in the pipe groups 24. After approximately three months of operation, two of the 49 tubules were partially occluded.

[Brief explanation of drawings]

FIG. 1 is an elevational cross-sectional view of a column housing the ultra-low flow rate liquid distribution device of the present invention. FIG. 2 is a top plan view of the apparatus of FIG. 1 taken along line 2--2 of FIG. FIG. 3 is an isometric drawing of the liquid dispensing device of FIGS. 1 and 2; FIG. 4 is an enlarged, cut-away side view of one of the distribution pipes, with one of the groups of tubules disposed within the distribution pipe indicated by the circled area FIG. 4 in FIG. FIG. 5 is an isometric drawing of another embodiment of the dispensing device of the present invention. FIG. 6 is a bottom view of the dispensing device of FIGS. 3 and 5. FIG. 10... Liquid distribution device, 12... Tower,
14... Column packing, 16... Support, 18... Storage tank, 20... Distribution pipe, 22... Conduit, 24 ...Canalicular group, 2
8... Inlet conduit, 30... Screen, 31. 32... Break-off coupling, 33...
. . . Departure flange, 34 . . . Supply tube coupling, 40 . . . Chain line showing the distribution pattern of the small tube. FIG, I FIG, 2 FIG, 6

Claims (1)

Claims: 1. The feed to the liquid distributor contains at least some incidental solid debris of a different density than the liquid, and the liquid to be distributed by the distributor lies in a virtual horizontal plane immediately below the distributor. in a vertical gas-liquid contact column which must be distributed in a substantially uniform pattern across the horizontal surface at a flow rate of less than 32.5 t/min/ft2 (0.8 gallons/min/ft2) per unit area of the horizontal plane. A liquid dispensing device comprising: a series of substantially horizontally spaced sealed distribution tubes; a transfer tube for maintaining the distribution tubes in fluid communication with each other; a liquid supply device for supplying liquid under pressure to the distribution pipe group;
a plurality of substantially vertically spaced tubes inserted into the bottom of the series of distribution tubes; The tubes extend a sufficient distance into the tube group to prevent blockage by solid debris at the bottom of the tube group, but do not extend far enough to the top of the tube group to prevent blockage from floating solid debris at the top of the liquid in the tube group. are not sufficiently extended and the bottoms of these tubelets are spaced apart from each other to reduce at least the distribution of liquid in the column across the imaginary horizontal plane of the column directly below the lower ends of these tubelets in the column. A liquid dispensing device adapted to produce a substantially uniform flow. 2. Dispensing device according to claim 1, in which there is a canalicular distribution of at least one canalicule per cross-sectional area of 129 ttl (201s2) in each case. 3. The series of distribution tubes are closed hollow tubes except that in these tubes there are openings for small tubes, connecting transfer tubes and liquid supply devices: these small tubes, transfer tubes and A liquid supply device is hermetically connected to the opening of said distribution tube group such that all of the liquid flow entering the series of distribution tube groups passes through the liquid supply device and the liquid flow exiting the series of distribution tube groups passes through the small tube group. The flow of liquid between the tubes in the pipe series and between the pipes in the series of distribution pipes is maintained with all the liquid feed inside the transfer pipe series and this pressure is equal to the column pressure just outside the series of distribution pipes. The system has also grown in size: a series of distribution pipes are in fluid communication with each other through a series of transfer pipes connected to them in a connecting arrangement; a series of distribution pipes for supplying liquid at a substantially constant flow rate and at a substantially constant pressure greater than the pressure immediately outside and about the series of distribution pipes; connected to a group: a distribution device according to claim 1 or 2. 4. The dimensions of the openings leading to the tubes, the length of the tubes, the dimensions of the tubes and the dimensions of the liquid supply device are adjusted with respect to the desired flow rate of the liquid to be dispensed, and the liquid supplied to the distribution device is The effect of the non-horizontal nature of the liquid outlet of the distribution device is to maintain a positive differential pressure on the liquid in the tube group relative to the environment immediately outside the tube group while entering from the bottom end of the tube group at the desired flow rate. 4. A dispensing device as claimed in claim 1, 2 or 3, wherein the dispensing device is arranged so as to minimize the 5. the feed to the liquid distribution device includes a liquid phase and a gas phase;
The liquid dispersion apparatus includes a storage vessel and a conduit creating a fluid communication connection between the series of distribution pipes and the storage vessel, the storage vessel being positioned in the column at a predetermined height above the series of distribution pipes. 5. The distribution device according to claim 1, wherein a constant liquid column pressure is maintained throughout the group of distribution pipes. 6. The storage container is of sufficient size to form a quiescent zone so that when the gas-liquid feed is fed through the storage container to the distribution device, the two-phase feed is
IJJ is kept sufficiently stationary so that the main part of the gas phase is separated from the liquid phase of the feed and escapes from the liquid through an opening in the top of the storage vessel, and the liquid is passed from the storage vessel into a series of distribution pipes. 6. A dispensing device as claimed in claim 5, which remains as part of the feed remaining as it descends the conduit device.