US2522425A - Tunnel-type bubble cap baffle - Google Patents

Description

P 1950 G. P. BAUMANN ETAL 2,522,425

TUNNEL-TYPE BUBBLE CAP BAFFLE Filed Aug.. 21, 1947 Patented Sept. 12, 1950 TUNNEL-TYPE BUBBLE CAP BAFFLE George P. Banmann, Elizabeth, and Cyril 0.

Rhys, Jr., Oranford, N. 1., assignors to Standard Oil Development Company, a corporation of Delaware Application August 21, 1947, Serial No. 769,860

2 Claims.

, The present invention relates to an improved fractionating and distillation means. The invention is particularly concerned with an improved design for tunnel type bell caps used in connection with the plates of i'ractionating and distillation towers. A specific adaptation of the invention involves the use of longitudinal and/or transverse bailles internally of fractionating plate chimney members and bell caps therefor. I

It is well known in the art to employ bell caps in conjunction with the trays or plates of fractionating and distillation towers. Ordinarily, in such equipment, a plurality of transverse plates are provided in a tower structure, dividing it into a plurality of chambers throughout its height. Liquids are introduced into the top of the tower to flow downwardly over the plates in succession. Gaseous elements are introduced lower down in the tower to flow upwardly thru chimney type openings in the plates. Bell caps, usually having slotted edges, are disposed telescopically over the chimney elements in such a manner that the gases are forced to escape around the lower edges of the bell caps through the liquid medium flowing over 25, The invention and its objects may be fully the plates.

A type of design presently employed involves I the use Of a comparatively small number of 10118,

generally rectangular chimney openings in the fractionating plates, over which are telescopically disposed tunnel type bell caps. The chimneys and caps are usually arranged on the plates with their long axis parallel to the flow of liquid over the plates. Although chimneys and caps, according to such design, have many advantages, it has been found that in many instances they may perform inefliciently, due to a tendency for the vapors rising through the chimney to develop preferential flow, whereby the greater proportion of the flow of vapors escaping from beneath a bubble cap may be concentrated at one point or area thereof. Although the use of tunnel type bell caps is attractive because of the lower cost of construction, because of this characteristic of tunnel type bell caps, it has been necessary to use the more expensive form of construction involving the use of small round chimneys and bell (cl. zen-114) same at all points on any one tray. Since plate distribution is a function of pressure drop through the caps, it can be shown that plate distribution depends upon the pressure drop of vapors escaping thru the plate liquid over the lower edges of the bubble cap. Using the long tunnel type bubble caps without the aid of the present invention, even though the initial distribution and pressure drop through the chimney is regulated by means of chimney chokes, a, preferential flow ofyapors can occur from end to end, or side to side, within the bell cap-after issuing from the chimney. When such swing action occurs, vapors will escape from under one side of the cap for a short time, and then the flow may switch to the other side or end of the cap. Such action causes the entire plate to swing or cycle.

caps in order to obtain proper distribution'and flow of gases thru the plate liquid sealing the space'between cap and chimney.

As indicated, regardless of the type of plate construction, it is desirable to have equal vapor distribution over the area of each tray for maximum tower capacity and eiliciency. In the ideal situation, the C. F. S. of the vapor per square loot of .tray area rising thru the tower is the Chimney chokes alone have been found not eiiective in preventing such action.

It is an object of this invention to provide suitable baflle means associated with the chimney and the bubble cap in such a manner as to provide even vapor flow over the entire length of the edge portions of a tunnel type bubble cap.

understood from the following description when read in conjunction with the accompanying drawings, in which:

Figure 1 is a plan view of a portion of a fractionating tower plate, showing a tunnel type bubble cap and chimney according to the invention with a portion of the cap broken away to show interior structure.

Figure 2 is a vertical section thru a portion of a tower plate showing a tunnel type cap and chimney according to Fig. 1, along the line 11-11 thereof.-

Figure 3 is a side elevation of a combination chimney and cap baflle.

Figure 4 is an end elevation of the bafl'le.

Figure 5 is a side elevation of the longitudinal ballle.

Figure 6 is a side elevation of a transverse ballle.

Referring again to the drawings, the numeral I designates a 'fractionating tower tray, having an elongated vapor chimney 2, over which is telescopically disposed a tunnel type bell cap 3. A longitudinal baille is indicated by the numeral 4. This ballle is provided with upwardly extending slotted portions la adjacent to each end, and adapted to fit over and engage the end edge portions oi the chimney 2. Slotted portions 4b are also provided in the baflle l to receive one or more transverse baflle members 5. Each such member, as particularly shown in Fig. 6, is provided with downwardly extending slotted portions a, adjacent to the outer edges of the baffle adapted to fit over and engage the side edge portions of the chimney 2. A centrally disposed slotted portion 51) may be provided to coincide with the slotted portions of lb of the baiile l, in order to provide a combination bailie having longitudinal and lateral portions, the upper edges of which are in the same plane.

As shown in Fig. 2, when the bames are disposed over the edge portions of the chimney 2, the tunnel type cap 3 will be supported by the upper edge portions of the baflles so that the lower edge of the bubble cap is disposed in spaced relation to the surface of the plate I, with the lower edge portions of the baille members 4 and 5, which overlap and extend beyond the chimney 2, in engagement with the surface of the plate I. By means of the baiile arrangement described, there is provided within the chimney and the bell cap a series of compartments of which a portion of each compartment lies within the chimney element 2. Preferably the portions of these compartments which lie within the chimney element 2 are of substantially equal volume. If desired a chimney choke 2a may also be used in conjunction with the baflle elements as described. Also where indicated by operating conditions, the number and type of baflle elements utilized may be varied without departing from the inventors concept. For example, longitudinal bames or transverse baflies'may be used alone, together or in combination with chimney chokes, and the number of transverse or longitudinal bailies used in combination with each other may be increased or decreased to suit operating conditions. The flow of vapors thru the compartmented chimney and bubble cap and their escape through the plate liquid surrounding and sealing the cap are illustrated in Figure 2.

In operation, vapors from the space below the plate as illustrated, flow upwardly through the chimney I, being divided in a substantially uniform fashion by the baille members 4 and 5. In the chimney space, and in the space within the bell cap itself, preferential flow or swing action is likewise prevented by the baffle members 4 and 5, all the vapors entering any compartment being forced to escape over the comparatively limited lower slotted edge portions in that area of the bell cap.

While the invention is generally directed towards the improvement of the distribution of upflowing gases in a distillation or fractionating tower, wherein relatively large bell caps are employed, the invention has been set forth and described primarily with reference to the use of means for controlling the flow of vapors within the bell caps and chimneys associated with a fractionating tower plate. It is preferred to use a combination transverse and longitudinal banie element but, as indicated, either may be used without the other, and some of the benefits of the invention will be obtained. Although illustrated and described in its preferred embodiments, it is to be understood that the invention is not considered as limited by such disclosure for the purpose of illustration, but only by the appended claims,

We'claim:

1. In combination with an elongated, substantially rectangular, walled, chimney member opening upwardly through a bubble plate, said memher having an upper end terminating above said plate in vertically spaced relation thereto, and a substantially rectangular walled, bubble cap for said member adapted for disposition over said cap in vertically and peripherally spaced, telescopic relation thereto, internal bafile means for said chimney and cap, comprising one baflle element longitudinally of said chimney and cap along the center line thereof, at least one lateral baille element for said chimney and cap disposed in fitted, intersecting relation to said longitudinal element, an inner portion of each element extending downwardly into said chimney in edgewise contact with opposite inner wall portions thereof, opposite outer end portions of each element exteriorly of said chimney extending in edgewise contact between an outer wall surface of said chimney and an inner wall surface of said cap and downwardly therebetween into contact with said plate, and an upper baille element portion uniting said inner portion and outer end portions as an integral unit in one plane, said upper portion extending upwardly from the upper end of said chimney, terminating in vertically spaced edgewise relation thereto, said upper and outer portions adapted to support said cap in spaced telescopic relation to said chimney element, and in vertically spaced relation to said plate, said baflie elements forming with the chimney and cap, interiorly thereof, a plurality of substantially uniform,noncommunicating compartments individually opening outwardly below said cap adjacent the plate.

2. Apparatus according to claim 1, including a chimney choke, formed integrally with the inner portions of said baille elements, supported thereby within said chimney member in an intermediate horizontal plane therein, peripheral edge portions of said choke extending into laterally spaced relation to the inner wall surface of said chimney member.

GEORGE P. BAUMAN'N. CYRIL O. RI-IYS, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,918,005 Urquhart July 11, 1933 1,961,711 Rosenow June 5, 1934 2,084,726 Duey June 22, 1937 2,225,390 Ostergaard Dec. 17, 1940 FOREIGN PATENTS Number Country Date 3,708 Great Britain July 30, 1883 4:324 Great Britain Mar. 19, 1890

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