US2449587A

US2449587A - Vertical heating and circulating tube still

Info

Publication number: US2449587A
Application number: US568374A
Authority: US
Inventors: John M Chambers
Original assignee: Arthur D Little Inc
Current assignee: Arthur D Little Inc
Priority date: 1944-12-15
Filing date: 1944-12-15
Publication date: 1948-09-21
Anticipated expiration: 1965-09-21

Description

Sept. 21, 1948. J. M. CHAMBERS 2,449,587

VERTICAL HEATING AND CIRCULATING TUBE STILL Filed Dec. 15, 1944 2 Sheets-Sheet l INVENTOR ATTORNEYS Sept. 21, 1948. J. M. CHAMBERS 2,449,537

VERTICAL HEATING AND CIRCULATING TUBE STILL Filed Dec. 15, 1944 2 Sheets-Sheet 2 ATTORN EYS INVENTOR I Patented Sept. 21, 1948 1 mhiscinvention el'aite to methodandzapparatust tfor rdistillation wherebyiwapor is separated 1 from axrsolutiony the term solution heingtusedxbroadly iavS ireferringtto: any more for lessxoonoentraitedusolution of solids, liquids *ori gasesln a mediumithat is :wlihbeimpeliedi the' desiredidireotiu men:

c-sziurtheri r-advant'agezlaccording- & 151 ,1 1 m mm V I; thatthe concentration-ofisolution in thevaporize- .i tion cchamherawis kept more tunitormsend formadsaliquidunderitheimaihtained conditionstot tem-i -.D rature.a,nd pressure i It is =2; purpose ofvthis' iinven'tion totimprove the operation -and"i effectiveness moi? the: vaporization irportifon ofza distillationsystem. amt-This invention relateswparticul'a y -=t1on-,. systems: :flwhere'in solution to beidistilled is boiled; in medically-extending messages 1 with rup- .-ward;flow of the boiling solution within the past sages and recirculation; of-the 3 solution through Q etdown-comer to the zlowen-endswot the passages pfor rebollinglof theisolution therein-w sax wit-J2; "It is .a feature of. the present *inventiomthat in a distillation; system :of the. character -referre iv to to v tionwoftundesirahle zones 0 excessive solute oncentrationis minimized: :1"

-. rpl 'urtherl purposesm-features and advantagestlof this invention iwill be apparent connectionwith the followingidescriptioni g m r tthls rinvention; which is. shown: for purposes a: il-

lustratlon'lnthe accompanying drawing, wherein p Fig. lzis L a/side elevation, largely diagrammaitic, 10f: distillatlonr-apparatus according torthis rinven- 1 $1011; Whichvis 1 shown,domillustrative purposesg ies vpart of a distillation system' of the vaporicompression type. 1

w aF'iQ- 2 is; an :enlarged rtiew of 1 th wvatnoriz'tttion v-andawheet exchangemzportions: of w the zapparatus -shown ;,in :Fi 151th: "view heinga-:=sidE' levation the incomlngmfeedrof fresh solution instead :1 of ma1ttlmdnsegtlon,

1:beingwfed indiscriminately into the -body, of @so-B 1 lution inthe wvaporizationwchamber as ha's been the, general priorfipractlce, :is ifed intopthe downcomer portion of the system: -It-iissawturther.fea-

arms-13 i yatdetanipmn ietv of themfee mafia tteeddiseharge.header,i a,ndw 4.;9155 91 sd tail sideelevation of the epparatus shown in Fig. 3.

ture Qfwthis invention;thatiitheyincomingtfeed ;1 he sol1ltion;,to be 1distilled isteontelnetl inzthe is discharged ;-,into 7: the downgcomer through. an i;- ejector that vforcibly; ejeotszthelncoming feed into i the down-r-comer :the, direction fotxnormalz now of solution through the down-comer: Itlls armrvvapor!tutlon chamber, IIL. :Wlthinzthe vaporization chamb ris the heat: exchangrpwhlch ls'in the fornrot epplurality or ,verticaly-tubes Ill that ere hel d 111 1130511301! by the barrier plates 1 =1: and

ther zfeatureaofythis invention-that the outlet for 13mm. hich are. open-ended at their upper and withdrawing: concentrated-solution;from the sys- 1.

.lower endso In; the "space about the exterior: :of the tubes H and between barrier pletesatll: and i 2:5 9, heated fluid.- eawbe supplied for? the purpose maintaining ,the heated :fluid in out-of-v-contact heat exohenge relationiwith thewsolutl'on within Lthgtubes lLso thatybymaintaimngpthefiuidtat it temperature abovethe boiling point otthe' soi- H lQPs w thim he ubes H, t e soluttonoin the tubes will hoilond generate t-tvaporwwhichi rises in tion ofithei system ,thegcirou-lation totwsolution to 40 vthe }tuhes end.esjwpes intozthe;vaporwregionilla and nthrouzhentheax o mew passagestandt ibaok through -the down-,pornercisdmprovecl;I imamfo s nt i 1;du wh e .fact th t incoming f e d; lS;atjj!a lqwemtemperature than thesolutlon bemglboiledwithin the-boiling; assages. -1- aB tmixv mg the cooler in pmlp ifeedmwlth,thediquid in i h do o-m er the t erature of thei-liqulddn the down-pointer. is kept get a minimum. the eby hp d t a 1 m xlm mwmtthisman m ertm a out? 7 va orz pw mb r @Theigen ration ofya'nor n,

normal ,liquicl level of? 'SOhltfiODgiill the o heatih pfthe solutio wl by t,

time. Iii-tame is weryxsubstantlaL-z MfllfeLYifordllustration;

the vaporization chamber escapes into the vapor region 13, and, in' order to eliminate entrained droplets of solution, can be passed through any suitable type of liquid-vapor separator, which, for purposes of illustration, is shown in the drawing as comprising the balilcs 15. The vapor then passes through the low pressure vapor line 32 to the compresssor l6 which may be of any suitable type and which may be driven by any suitable source of power such as the motor II. The vapor compressed by the compressor I6 is directed by the compressed vapor line It! to theregion surrounding the tubes H. The vapor compressed by the compressor is compressed to a pressure such that its condensing temperature is above the boiling point of the solution within the tubes Ii. Such being the case the compressed vapor will be condensed and give up its latent heat of vaporization as well as any sensible heat carried thereby to the boiling solution with which it is in out of-contact heat exchange relation. densate is taken off through the line IS.

The concentrated solution that results from the boiling of solution in the vaporization chamber, after the separation of vapor therefrom, is directed from the vaporization chamber by the line 20, which is provided with a receiving mouth 33 which determines the normal liquid level of 5011?. tion in the vaporization chamber I.

At the bottom of the vaporization chamber ber through line 20, and the hot condensate withdrawn through the line l9, are directed in outof-contact and counter-flow heat exchange relation in preheater heat exchanger 2| with incoming feed of fresh solution which enters the system through line 22 and is directed from the heat exchanger 2| to the vaporization chamber; ID by the line 23. The feed is preferably forced into the system as by the pump 24 although a gravity force feed can be employed if desired. The pump 24 may be of a fixed displacement type so that the amount of feed entering the system can be controlled by regulation of the speed of the pump. Alternatively a constant pressure type of pump may be employed, or a constant pressure gravity feed may be employed, together with a valve 25, or other flow regulating device, to control the rate at which the feed is introduced into the system. The employment of a preheater such as the preheater 2| is not essential to the practice of this invention, but is especially desirable in a distillation system of the vapor compression type. A- drain 30, controlled by valve 3 I, is also provided.

Features of this invention relate to the manner of introducing the feed of incoming fresh solution into the body of solution in the vaporization chamber. In the embodiment shown, the feed is directed to the header 26 by the feed line 23. The

. header 28 has a plurality of lines 21 projecting downwardly therefrom which terminate in nozzles 28.

It is to be noted that the feed is injected into the system in the down-comer passage H of the disillation unit. This has the effect of increasing the rate of circulation of solution in the vaporization chamber. This increase in rate of circulation is due to the fact that the feed of fresh solution at a lower temperature is of a greater density as compared with the balance of the solution in the vaporization chamber. There is, therefore, a greater density differential between the solution in the down-comer l4 and the solution in tubes II, which fact promotes convection circulation. This in itself is one feature and advanas shown, to further promote the circulation of The con- 7 vented. Difficulties of this character have been the solution by the ejector action of the feed of fresh solution in being discharged into the solution in the down-comer N in the direction of normal liquid how in the down-comer. Theyincoming feed is ejected as a let which affords a positive propulsion of the liquid in the downcomer in the desired direction.

It may also be noted that the incoming feed is commingled with the solution in the vaporization chamber so that the outlet for concentrated solution from the vaporization chamber is intermediate between the upper ends of the tubes H and the point of introduction of the feed. In this manner the incoming feed is caused to become thoroughly commingled with the solution in the vaporization chamber and to pass through the tubes H before any of the incoming feed is taken fromthe vaporization chamber. This is of considerable advantage since premature discharge of insufliciently concentrated solution is prevented and the complementary undesirable building up of solution of excessive concentration is preincident to other types of apparatus due to disproportionate amount of feed passing prematurely out of the overflow line.

More uniform distribution of the boiling solution amongthe tubes II is also afforded in the practice of this invention. Apparatus and method of the character aforesaid can advantageously be used, for example, in a distillation system designed to recover pure water from sea water. In such an operation the feed can, for example, be fed into the system at the rate of gallons per hour and introduced into the vaporization chamber after having been preheated to about 200 F. in the preheater heat exchanger 2|. Using the method and apparatus of this invention the circulation of solution through the down-comer H can be at the rate of about 12,000 gallons per hour in a system of the capacity aforesaid.

It is apparent that the foregoing embodiment of the invention is merely illustrative and that the method and apparatus can be varied considerably without departing from the scope of this invention. Thus it is apparent that the location from absolutely vertical) provided the upper end is above the lower end. The down-comer may have appropriate connections, elbows, etc.,,as may be required to connect it in operative relation for returning the solution from the upper to the lower ends of the tubes H.

The feed introducing means may be varied.

-' Thusif desired, a single feed line may introduce the feed into the down-comer, instead of the plurality of-lin'es 21. Moreover, the nozzles 28 .or the equivalent, may bedispensed with, but the useof the nozzles 28,-or equivalent jet producing means, is to be-preferred in order to obtain the ejector impulsion, action. In this connection it may be noted that the pump or other pressure supply means for the feed cooperates with the nozzles 28 -or the equivalent to positively impel the solution in the down-comer.' The point of introductionioi" the feed solution into the downcomerisordinarily'adjacent the upper end, as

shown {but may be at'any other location in the down-comer. Preferably, the feed is introduced into the down-comer at a point substantially above the lower-ends of the tubes ll.

I The tubes ll may .be as shown or may be in I the form oiany other suitable passages. They maybe vertical, as shown, or in any other vertically extending position, within the meaning of the term vertically extending that has been mentioned above. i

The vapors which are introduced for condensation in out-of-contact heat exchange with solutions in the tubes Il may, "of course, be derived from other sources than thecompressor it. Thus the vapor may be supplied from an independent boiler and may be other than the vapor which is evolved inthe vaporization chamber. Moreover, hot combustion gasesor other heated fluid may be used.

While I this invention has been described in connection with atypical example of the practice thereof, it is to-be understood that this has been done for illustrative purposes only and that the practice of this invention may be varied within the-scope thereof as defined by the language of the following claims.

I claim: 7

1. Distillation apparatus for the separation of vapor from a solution which comprises a vertically disposed vaporization chamber, a heat exchanger within said vaporization chamber in the form of a heating chest which is disposed between the upper and lower portions of said vaporization chamber and which consists of upper and lower walls, a. plurality of vertically extending conduit passages extending through said heating chest and said walls in open communication with solution within said vaporization chamber above and below said heating chest, and a single vertically extending down-comer passage centrally located in said chest and of substantially larger flow capacity than the individual conduit passages 01' said plurality of conduit passages for returning solution from the portion of said vaporization chamber above said heating chest to the portion of said vaporization chamber below said heating chest, said heating chest separating the said upper and lower portions of said vaporization chamher from each other except for said conduit passages and said down-comer passage, means for introducing a fluid at a temperature above the boiling point of solution within said vaporization chamber into said heating chest to heat and boil solution within said conduit passages by out-ofcontact heat exchange through the walls of said conduit passages, means for removing vapor from the upper portion of said vaporization chamber, outlet means for withdrawing residual concentrated solution from the said vaporization chamber, and feed means for supplying fresh solution into said vaporization chamber, said feed means being arranged to forcibly discharge a stream of incoming fresh feed downwardly into said downcomer passage in the normal downward direction of flow of solution within and through said downcomer passage.

2. Distillation apparatus according to claim 1 wherein said means for supplying fresh solution into said vaporization chamber includes jet means located adjacent the upper end of said down-comer passage for forcibly "ejecting a jet of incoming feed downwardly into said downcomer passage.

JOHN M. CHAMBERS.

REFERENCES CITED The following references are of record in the