US1558811A - Process for condensing vapors - Google Patents

Description

'oct 27,1925. 55ml Y E... W. ISOM ET Al.

PROCESS FOR CONDENSING VAPORS Original Filed June 1921 3 Sheets-Sheefi 1 INVENTORS Edward W150? I JbfiflfTBe/l w M$W ATTORNEYS E. W. iSOM ET AL PROCESS FOR CONDENSING VAPORS inal Filed June 25, 1921 3 Sheets-sheet 2 INVENTOR5 Edward W Asa/27 finale,

ATTORNEYS Patented Oct... 27, 1925.

UNITED STATES PATENT OFFICE.

EDWARD w.1som, or Loons'r VALLEY, AND mm :s. BELL, or BROOKLYN, NEW YORK, ASSIGNORS '10 SINCLAIR nnrmme COMPANY, or CHICAGO, ILLINOIS, A con PORATION 0F MAINE PBQCESS FOB CONDEKSING VAIOBS.

Original application filed June 23, 1821, Serial No. 479,796. Divided and this application filed November To all whom it may concern:

Be it known that we, EDWARD W. ISOM and JOHN E. BELL, citizens of the United States, and residents of Locust Valley, county of Nassau, and State of New York,

and Brooklyn, county of Kings, and Stateof New York, respectively, have invented certain new and useful Improvements in Processes for Condensing Vapors; and we do hereby declare the following to bea full,

clear, and exact description of the invention,

. sure distillate, therefrom. The invention ineludes an improved process of condensing the vapors from pressure stills, an improve process of fractionating pressure dlstillate, and an improved method ofoperatingpres sure stills.

In the process of the present invention,

the vapors from the pressure still are cooled and condensed by injecting them into a body of liquid of the same general COITI-r position as the Vapors themselves, the liquid body is cooled, and the cooling and condensa tion of the vaplors are promoted, by circulating the liquid ody in indirect heat exchangin relation with a cooling medium, such as re with advantage, be employed as the liqu1d body into which the vapors from the still are introduced. The condensation of the vapors thus results in the production of an additional amount of pressure distillate'or condensate of the same composition as that into which the vapors are introduced and l atively cool oil or water, and the circula successive liquid bodies may,

12,1924. Serial "no. 749,408.

by which they are condensed so that extraneous liquids are kept from direct contact with the condensed vapors although the vapors are intimately and directly mingled with the cooling and condensing body of liquid. Other oils or distillates, corresponding in character to the pressure distillate, mayyhowever, be employed.

The pressure maintained upon the body of condensate may be atmospheric, or it may be a predetermined pressure above atmospheric but lower than the pressure maintained in the pressure still. The reduction in pressure between the"still and the condensing means is employed to force the vapors into the liquid body and to thoroughly and intimately intermingle them there.-

with, and to maintain a rapid circulation ofthe liquid body and admixed vapors and condensate in heat exchanging relation with the external cooling medium whereby heat transfer between the circulating body and the cooling medium and the cooling and condensing of the vapors is promoted. The condensing operation thus also serves to effeet a reduction of the still pressure-and the injection of the vapors into the liquid" body may be regulated to control the pressure reduction. The rapid agitation and circulation of the liquid body by the introduction of the. still vapors also assists in maintain? ing an approximately uniform temperature in the liquid body;

The rocess of the invention may also be carried out to fractionally condense the vapors from the pressure still and to produce a series of condensates of progressively lighter character by injecting the vapors from the still into a liquid bod ,i'njecting the vapors uncondensed there y into a second and cooler liquid body, and so forth with progressive reduction in pressure from and with the production of a step to step corresponding series of condensates. The progressive reduction in temperature of the advantageously be effected by circulating the external ooolin medium in indirect heat exchanging re ation with them in counter-current to the flow of the still vapors, so that the fresh and 'coolest cooling mediumjis brought into heat exchanging relation with the coolest liquid body, and the cooling medium as, it is progressively heated by absorbing heat from the vapors and the liquid bodies is successively brought into heat exchanging relation with the hotter liquid bodies.

Any permanent gases discharged with the vapors from the pressure still are also intimately contacted with the liquid body or bodies into which the stillvapors are introduced and are thereby efi'ectively cooled, so that any permanent gases and uncondensed vapors escaping, uncondensed, from the condensing operation of the present invention are cool, and 'may be withdrawn and sub-" jected to suitable treatment for the recovcry of the condensible constituents, or for the utilization of the condensable constituents or the permanent gases, as may be desired. Due to the improvedcooling and condensing effected by the process of the present invention, however, only a minimum of unabsorbed permanent gases and uncondensed light vapors need be permitted to escape from the condensing'operation.

The invention will be further described in connection with the accompanying drawings which illustrate, somewhat diagrama is defined in the subj'oined claims, in which we have endeavored to distinguish it from the prior art so far as known to us without, however, relinquishing or abandoning any feature or portion thereof.

Inthe accompanying drawings, 7

Fig. l represents, in elevation and partly in section, a condensing apparatus adapted for the practice of the invention,

Fig. 2 is a section on line 2-2 of Fig. 1,

Fig. 3 is a similar elevation, partly broken away, of a difi'erent form of condensing apparatus adapted for the practice of the invention,

'Fig. 4 is a section on line 44 of Fig. 3.

Fig. 5 is an enlarged vertical section view showing an injection nozzle, and.

Fig. 6 diagrammatically represents, in elevation and partly in section, a pressure still and condensing apparatus arranged for operation in accordance'with the present invention.-

It will be evident that the pressure still may be of different construction and the pressure still illustrated is merely for urposes of exemplification. In the crac ing of hydrocarbon oils in a pressure still, the entire body of cracked vapors may be withdrawnor these vapors may be refluxed un- .forms the subject matter of a copending applicationjfiled June 23, 1921, Serial No. 419,796 ofwhich this application is a division.,

Referring to Figs. 1 and 2, the condensing apparatus there illustrated is arranged for fractionall Y condensing the vapors in 3 stages, an comprises 3 condensing units, 6, 7 and 8. It will be apparent that a greater or lesser number of condensing units may be employed for the separation of a corresponding number of fractions. The condensing units are arranged so that the vapors from the still are assed first into the lowermost' unit and t en successively upward through the middle and the upper unit.

Cooling coils, through which an appropriate cooling medium is circulated, are arranged in theunits to cool the contents thereof.

The condensing units are alike except in respects which will be particularly pointed out, and the description of one of them will sufiicefor all. Each of the condensing units illustrated comprises a cylindrical drum or shell 9 having closed ends 10 and 11. In operation, these drums are maintained partially full of oil; the oil level may be. maintamed, for example, at about the height indicated by the dotted line in unit 8. A

pair of downwardly extending hollow legs 12 and 13 connected by and con'lniunicatmg with the drum, are arranged'there below and are also connected by the pipe 14."

The vapors from the pressure still, or from the preceding condensing unit, are introduced into the pipe 14 at one end through a connection 15. The vapors from connection 15 are introduced throu h a nozzle 16 arranged m the pipe 14 so t at the vapors enter theipe 14 in the direction of its length, an ,with relatively great velocity due to the expansion through-the nozzle 16. The injection of the vapors promotes and maintains a rapid circulation of the oil from the drum down the hollow leg 13. through thepipe 14 where it admixes with the vapors, and u the hollow leg 12 back to the drum. In t e drum,.the oil circulates from the inlet of'the leg 12 to the 'outlet of the leg 13 and is cooled as it passes there- .spective condensing units.

through. The injected vapors are thoroughly and intimately mixed and intermingled with the circulating cooled oil in the pipe 14: and this mixture is also brought into contact with the oil in the drum and with the cooling means therein. The uncon densed vapors and fixed gases are also forced-to'bubble up throughthe oil in the drum to the vapor space above. The liquid body in the drum, and the vapors and gases admixed with it and collecting above it, are cooled by heat exchange with the cooling coils. 17 through which a cooling medium is circulated. As illustrated, the cooling coils 17 are in the form of'flat involutes substantially filling the cross section of the drum, arranged at intervals along the drum, and connected together in series. In each condensing unit the cooling fluid enters the cooling coils at the end remote from the point atwhich the admixed vapors and circulating oil are introduced into the drum so that the flow of cooling medium through each drum is also countercurrentto the flow of the circulating body of oil and admixed components therein. A draw-oft 26 is provided for withdrawing condensate from each of the drums.

In the apparatus illustrated, the cooling medium is introduced into one end of the coil in the uppermost drum through connection 18, is discharged from the cooling coil .in the upper drum to the next drum through connection 19, is discharged from the cooling coil in this drum to the cooling coil in the lower drum through connection 20 and is discharged from the cooling coil in the lower drum through connection 21. The vapors from the lower drum are introduced into the lower drum through connection 22, the uncondcnsed vapors and gases from this drum into the intermediate drum through connection 523, and the uncondensed vapors and gases from the intermediate drum into" the upper drum through connection 24, any uncondensed vapors escaping through con nection 25. The circulation of the cooling medium and of the vapors through the entire series of condensing units isthus maintained in a general counter-current relation as is the circulation of the cooling medium and of the condensate and vapors in each of the re- The pressure upon the vapors is progressively reduced by expansion to each one of the nozzles as the vapors pass through the successive units. In this way the several condensing units may be maintained at progressively lower temperatures so that the cooling medium is brought to its highest temperature in the lowermost unit into which the vapors are introduced in their hottest state and so that the condensates collecting'in the several successive drums are progressively lighter.

Water may be employed as the cooling medium or a suitable oil may be so used. Where -Water is employed, the condensing operation may be used to preheat the water for use in steam boilers. An oil suitable for use as charging stock in the pressure still may be employed as the cooling medium, being thereby preheated, and may be introduced into the pressurest-ill, in. whole or in part, after being used for cooling and condensing the vapors.

,In carrying out the process of the invention in the apparatus illustrated, the con- (lensing drums are partially filled with an oil corresponding in character to the desired condensate, and the vaporsfrom the pressure still areinjected into the circulation pipe of the lowest unit. The vapors are thus mingled with the oil in the circulation pipe and a rapid circulation in the direction indicated by the arrows is set up. The vapors are partially cooled and condensed by inter-mixture with the cooler oil circulating through the circulating pipe from pressure. The condensate may be drawn off from the condensing units in a continuous manner or from time to'time as desired.

It is desirable to maintain the circulation of cooling medium through'the cooling coils in each drum sufficientto absorb the heat of the fresh vapors introduced therein and to reduce them in'temperature to the temperature of the main body of liquid in the drum. The rapid circulation and agitation i'naintained by the introduction of the vapors into each of the condensing units and the intimate admixture and contacting of the vapors with the circulating oil and with the relatively larger body of oil in the drum'promotes the thorough cooling and condensation of the vapors and promotes the maintenance of a uniform temperature in each condensing unit so that the introduced vapors and gases are brought substantially to equilibrium with the body of oil in each drum. In this way. a well defined difference in temperature is maintained in the successive condensing units offthe series anda correspondingly close or accurate fractional condensation of the vapors can be effected.

The operation ot'this apparatus in accordance with the present. inventionwill be further illustrated by the following example: In cracking a gas oil charging stock 100 F. respectively. In the last unit thetcmperature may be reduced to within a few degrees of the temperature of the entering cooling medium.'- Any uncondensed vapors escaping with the permanent gases from the last unit may be condensed in the usual way.

A somewhat different type of condensing unit is illustrated in Figs. 3, 4 and 5. In this apparatus the external circuit is arranged communicating with the ends of the drum and additional cooling coils are ar-" ranged in the vapor space of the drum for further cooling the vapors. The circulation pipe 31, having the T connection 33 therein, is arranged below thedrum 30 connecting to its ends 32 through connections 3i and 35. The vapors to be cooled and condensed.

are introduced into the T 3?) through con nection 86 where they mingle with oil flowing from the drum 30 through connection 35. The vapor .pipe 36 is secured to a cap plate 37 on the T and a nozzle 38 having a reduced outlet 39 is arranged within the T to receive the vapors from pipe 36 and.

discharge them axially into the circulation pipe 34. The cooling coils 40, 41 and 42 are arranged longitudinally of the drum, the coil 40 being arranged inthe upper part of the, drum to further cool and condense vapors and gases bubbling up through the body of oil in the drum. Uncondensed vapors and gases are discharged through outlet 43 and connection 44 is arranged for witlulrawing condensate. \Vhere fractional or multiple condensation is: desired a plu- 5 rality of their units-may be employed as in the term first described. The operation of this form of apparatus is substantially that of the apparatus which has been previously described and it may be employed in a' similar way in carrying out the process of the invention.

The pressure still illustrated is of the gem cral construction described in U. S. Letters Patent No. 1,285,200 granted to the Sinclair Refining Company. November 19, 1918 on.

the application of Edward \V. Isom. This pressure still. which is illustrated in a diagrammatic and conventional manner, comprises the bulk supply tank 45, vertical heating tubes 46 arranged in the heating flue of a. furnace, the circulating pump 47 and circulating connections for circulating Oll from the-bulk supply tank to and through the heater and back to the bulk supply tank. A tan-draw-ofl' is provided at 48. A reflux tower 49 is arranged-above the bulk supply tank and receives the vapors therefrom through vapor-line 50. A connection 51 is arranged for introducing fresh oil into the upper end of the reflux tower in direct contact with the vapors therein. A return line 52 is provided for returning reflux and admixed fresh oil to the 'still.- The vapors escape from the reflux tower through the vapor-line 53 having the pressure regulating and reducing valve 54 therein. The vapors escaping from the reflux lower may be introduced into the condenser at still pressure or the pressure may be reduced to an intermediate valve by controlling the valve 54. The vaporsare injected into the condensing unit (one similar to that shown in Fig. 3 is illustrated) through connection 55. A bypass connection for discharging the vapors is also provided at 56. In the condensing unit the vapors and gases are cooled and condensed as has been described, a cooling medium being circulated through connections 57 and 58, uncondensed vapors and gases being discharged through connection 59, and condensate being withdrawn through connection 60.

It will thus be seen that the present invention provides an improved method oi cooling and condensing the vapors from pressure stills and of scrubbing the pressure still gases. .The condensing action is obtained by injecting the vapors and gases into a stream or streams of liquid, corresponding in character to the pressure distillate, which is circulated from and back to a relatively large body of the liquid which is cooled by an external cooling medium, the circulation being maintained and promoted in an advantageous way by utilizing the still pressure for injecting the vapors and gases into the circulating liquid. The vapors and gases are initially cooled and condensed by intermixture with the circulating stream or streams into which they are introduced, while the condensation of the vapors and the absorption and scrubbing of the gases are further completed by contact with the relatively large body of cooler liquid into which the circulating liquid stream or streams and the gases and vapors admixed therewith are introduced.

It will further be seen that this invention provides'an improved method of tractionally condensing the vapors from pressure stills'in which the separation of tho-progressively lighter fractions of the pressure distillate is eli'ected by successively passing the vapors through a series of liquid bodies, of a character corresponding to the desired fraction maintained at progressively lower temperature by indirect cooling and in which 1. An improved method of condensing hy-' drocarbon vapors, which comprises main"- raining a body ,ofcondensate of correspond ing composition, cooling said body, circulating a stream of said condensate from and to said body through an external circuit, in-

- jecting the vapors into said circulating stream and maintaining the circulation by the injection of the vapors.

2. An improved method of condensing hydrocarbon vapors, which comprises main: taining a plurality of bodies ofcondensate of corresponding composition at progressively lower temperatures, circulating a stream of said condensates from and backto each of said bodies through an external-circuit, injecting the vapors into the circulating stream of highest temperature, collectin the uncondensed vapors therefrom and injecting them into the circulating stream of next lower temperature and so on, and maintainingthe circulation in eachcircil'i't by the injection of the vapors.

' 3. An improved method of condensing hydrocarbonvapors, which comprises maintaining, a plurality of bodies of condensate of corresponding composition at progressively lower temperatures, by passing a cooling medium in indirect heat exchanging relation therewith in counter order to the tempera ture gradient, circulating a stream of said condensates from and back to each of said bodies through an external circuit, injecting the vapors 1nto the circulating stream of highesttemperature, collecting the uncondensed vapors therefrom and injecting them into the circulating stream of next lower temperature and so on, and maintaining the circulation in each circuit by the injection of the vapors. v

4. An improved method of condensing hydrocarbon vapors, which comprises maintaining anelongated body of condensate of corresponding composition, circulating a stream of condensate from one end of said body through an external circuit back to the other end, injecting the vapors into said circulating stream and maintaining the circulation by the injection of the vapors, and

circulating a cooling medium in indirect heat exchanging relation with the said body in a direction generally countercurrent to the circulation of condensate therein.

5. An improved method of condensing the vapors from pressure cracking stills for cracking hydrocarbon oils,.which comprises maintaining a body of the condensed pressure distillate, cooling said body, circulating a stream of said condensed distillate from andto said body through an external circuit, and reducing the pressure upon the still vapors and introducin them into said stream and thereby maintaining circulation through said circuit.

culation by the injection of the vapors, and circulating a cooling medium in indirect heat exchanging relation with the said body in a direction generally countercurrent to the circulation of condensate therein.

In testimony whereof we affix our signatures.

EDWARD W. ISOM. JOHN-E; BELL.

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