US1799734A - Heat exchanger - Google Patents

Description

April 7, 1931- W. M. CROSS 1,799,734

HEAT EXCHANGER Filed DeC. 17. 1924 2 Sheets-Sheet l NVFNTR. WalTer @V055- f ,47 f/zz@ ATTO NEY.

W, M. CROSS HEAT EXCHANGER April 7, EQSE.

. 1924 2 Sheets-Sheet 2 Filed Deo. 17

7' d INVENTOR. W Wa'er M-CVOSS- l ATTORNEY.

Patented Apr. 7, 1931 warren 1r. caoss, vor KANSAS crrr,

ro essonne rnonuc'rs comrANY, 'non or Dmwnnn MISSOURI, ASIGNOB, BY MESNE ASSIGNMENTS,

INC.,

OF WILMINGTON, DELAWARE, A CORPORA- HEAT EXCHANGEB y vA ppucazimi mea member 17, 1924. 'serial no. 756,474.'

This invention relates to improvements in heat exchangers, and refers more. articularly to a tower construction adapta le for use in treating vapors, particularly hydrocarbon 5 vapors in their ltravel from a distillation source to a stage of condensation. y

Among the objects-of the invention are, to provide a tower construction in which the vapors are introduced into 'the bottom and are caused to rise through a series of pools `of liquid, which pools are successively'cooler in temperature from the bottom to the topof the tower; to provide a construction whereby the liquid is coursed in an opposed direction to the vapors, separating out from'the vapors in the separate pools a condensate which overflows to the pools below and is collected in the bottom of the tower; to provide a' construction in which a relatively hot medium is introduced to the bottom of the tower in order to reboil the collected condensate or cooling liquid in order to'drive of the lighter fractions or relatively lowboiling point va ors for retreatment in the tower; to provi e a mechanical construction devised to withstand the relatively wide range of temperatures to which'it, is subjected and one in which expansion and contractionis com ensated for particularly in the lower reboi ing portion,

and a construction in which an eiiicient heat exchange is effected to reboil the liquid by passing the hot medium in a continuous passage through a plurality offrelatively small coils and during the travel of the hot inedium to provide an immense radiating surface and a more complete. heat exchange.

In order to prevent the. obstructing of the inlet to the 4reboiling ,element through dep- 0 osition and accumulation of.l deleterious matter from the medium, a plurality ofA inlets are provided in order that an alternate inlet may be used 'should .one become, objstructed. 'y

Fig. 1 is an'elevational. view of the tower with portion of the shell broken away.

Fig. 21s a view taken along `the line 2-2 in Fig. 1. 'Y Fig. l is inrlg. 1.

aview taken along the line 3-3 vfiow of stand pipes 5. The excess liquld -part of the invention, and for that reason is Fig. 4 is a sectional plan taken along the line 4-4 in 'Fig'. 1. A

Fig. 5 is a view taken along the line 5-5 in 4. l

Re erring to the drawings, the tower -is preferably constructed in the form of acylindrical shell such as that shown at-l, althou h a square, rectangular tower may as well is used. Centrally inthe tower are constructed a plurality of pans or separating partitions 2, through which extend risers 3 surmounted by caps 4.' -Liuid collects in pools upon the partition 2 an overflow or downcomer pipes 5 maintain the levell of the liquid onthe separate pools and permit the liquid to overiow tothe pool below. Vapors are introduced to the tower-through vapor line 6, controlled by a valve 7, and pass upwardlythrough the risers to the adjacent pool above, being caused to percolate or bubble through the liquid in the successive pools by the caps which surmount the risers and reverse'the ow of the vapors. i

In the upper portion of the tower are'positioned further cooling means in the form of coils Sand 9. Through these coils are circulated cooling mediums which further serve to separate out the higher boiling point fractions from the. vapors. The uncondensed vapors pass o through the-lined() to further treating stages notshown.- In each ofthe separate pools there is separated from vthe vapors liquid condensate .which accumulates and is maintained at a level by the overpasses in a reverse direction to the vapors, gravitating downwardly through the system to the bottomof the 'tower where it is collected and maintained at a level--shown by the dotted line ll--by an automatic liquid level regulating device 12. This device con trols the valve 13 in the drawof line 14. The function of this particular device forms no diagrammatically shown.

onll)7 p Y n the bottom of the tower is va reboiling unit which l consists of a fixed header 15, tubesl 16, a floating header A17 and a. housin 18-in which the loatinieader is positione The'func'tion off this re iler is to reheat and 10 reboil the condensate collected in the bottom ofthe toi-.ver in order to drive oil all but the relatively higher boiling point fractions, producing a more uniform redux condensate Withdrawn through the line 11i and eliminating the lighter fractions trom this oil body which materially increases the yield of distillate which passes over through the top ot the toiver in the form ci vapors.

As mentioned, this tovver is particularly adapted :for use in an oil treating system such as an atmospheric distillation process or a cracking process in which pressure is used. A heating medium such as the liquid residual material Withdrawn from the stage of conversion in a cracking system, may be circulated through the reboiling unit in order to give up its heat to the redux condensate in order to drive ofi the lighter tractions therefrom.` This hot liquid is introduced to the reboiling unit by ineens of either inlet pipes 19 or 20. A double inlet is provided in order that the operation of the apparatus need not. be .suspended should the loiver inlet line 19 become obstructed with accumulated material such as carbonaceous material suspended in the form of free carbon in the residual liquid.

The passage ot' this heating liquid through the reboiler, is shown best in Fig. 3. Being introduced through the inlet line 19., it is coursed tnrough the lower layer of tubes in the form oi: a double stream designated as 21, rising at the right end through the square header to the t'Wo tubes in the layer above, shown a 22, and passinfy thence in the pairs of tubes up and baclr and at the same time horizontally in a reverse direction to the layer below, Working' baclr lto the left side Where it rises again to the next layer 23. '"hus, the oil is coursed successively through the separate layers or" tubes to the top layer 2d and is discharged through the outlet pipe 25. it will be noted that the alternate inlet pipe 2G supplies the oil to the layer oi tubes 23, the third laycrabove the bottom row of tubes, and may be used as the inlet for the heating medium should the lorvcr tubes be come obstructed or clogged.

The hired header 15, shown in section in 3, is linedly mounted upon the side of the tower either by bolts, rivets or otherwise secured. i'jpposite the end of smh of tho tubes is emovable cleaning plug such as shown .26 order tha the tubes may be cleaned should it become necessary. lhe op posite ends of the tubes terminate in a floating header 1"? equipped with cleaning plugs Q7 and movably positioned at the end closure 18 which has cleaning plugs 28 opposite the plugs A in order that the tubes may be cleaned m both the hired end 15 and from moveable end 1'?, The purpose of the moveable header is to permit expansion and contraction of the tubes and metal parts due to Moorea the high temperature at which the medium is circulated through the reboiler. The oompound floating header 17 of the reboiler is preferably made up of individual sections 30, shown best in lig. 2, in order that it may be more easily assembled and repaired. These sections contact with each other at the faces 31 and are provided with lai-shaped members 32 fitting into suitable channels 33 in the adjacent sections in order to restrict lateral movement over each other while permitting unrestricted longitudinal movement. The bottom section is provided with a plurality of feet 34 which abut corresponding members 35 of closure 18. rlube supports may be positioned near the ends of the tubes to prevent sagging.

It is recognized that heretofore it has been common practice to pass a heating medium through liquid oil in a tower or introduce live steam for the purpose of driving oil1 the lighter fractions. lit is submitted, however, that there has not heretofore been a satisfactory apparatus for introducing a hot medium, such as the residual material produced in a cracking unit, and circulating it in the manner shown, providing for an ecient and effective heat exchange and preventing the clogging due to accumulated material and at the same time providing an apparatus which will satisfactorily prevent leaks due to ences sive stress and strain caused by the uneven expansion and contraction of the metals, resulting fromuneven and Wide temperature range to which the metal is subjected.

"vi/hilo this apparatus has been particularly described with reference to its adaptation to the treatment of hydrocarbon vapors, it is appreciated that it may, as Well, be used in the treatment ot other vaporous material, Water or other mediums being used in place of the oil in the reboiling element.

l claim as my invention:

1. A reboiling element for fractionating 1towers, comprising a unitary partitioned header, a compound partitioned header, a plurality of sets ot tubes arranged in series and connected into the partitioned headers to permit a continuous iloiv of the medium passing through the element, and inlet and outlet ports in one of the headers, the unitary header 'redly mounted in the tov/er, the compound header so mounted as 'to permit only longitudinal movement of its components.

2. A reboiling element for fractionating towers, comprising a partitioned liner header and a compound header, a plurality of sets of tubes arranged in series and connected into the headers to permit a continuous dow of the medium passing through the element, inlet and outlet ports for the lined header, the several members of the compound header being mounted in the tower so as to permit only horizontal movement thereof.

8. A reboiling element rior ractionating towers, comprising an integral partitioned header, a compound partitioned header, a housing for the compound header, a plurality of sets of tubes arranged in series and connected into the artitioned headers to permit a continuous ow of the medium passing through the element, inlet and outlet ports in one header, one header xedly mounted in the tower, the other movable therein to permit expansion and contraction of the metal, cleaning plugs opposite the ends of the tubes in both the fixed and movable headers, and separate plugs in the housing in aligned relation with the tubes.

4. A reboiling element for fractionating towers, comprising an integral partitioned header, acompound partitioned header, a plurality of sets of tubes arranged in series and connected into the partitioned headers to permit a continuous flow of the medium passingthroughtheelement,andinletandoutlet ports in one of the headers, one header fixedly mounted in the tower, the other movable therein to permit expansion and contraction of the metal, and an auxiliary inlet port for eliminating the necessity of discontinuing the flow of liquid through the reboiling element should one inlet port become clogged.

5. In a reboiling element for fractionating towers, a compound iioating header comprising' a plurality of independent, superimposed, movable header elements, and partitions within each element.

6. A compound floating header comprising a plurality of independent, superimposed,

movable header elements, each separate element being provided with a plurality of tired, horizontal partitions and a vertical partition defining separate chambers in said 40 elements.

. 7. In a header construction of the character described, in combination, a plurality of separate partitioned header elements independently movable, oppositely positioned sets of apertures in the header elements, sets of tubes connected into one set of apertures and individual closure plugs for the apertures of the oppositely positioned set.

8. A compound floating header comprising a stack of superimposed independently moveable header elements, and means to confine the movement of the elements to a single plane.

I 9. In a reboiling element for fractionating towers, a compound floating header comprising a plurahty of independent, superimposed, moveable header elements having V'- shaped members adapted to fit in corresponding channels in adjacent members.

so WALTER M. onoss.

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