US2020948A - Distillation system - Google Patents

Description

Nov. 12, 1935.y

J. D. KREls 2,020,948

DISTILLATON SYSTEM Filed Jan. 6. 1933 3 Sheets-Sheet l 48 52 2 50 52 f' 45 j \5^ la SV W ff {f3-@T Hf-"5i- NOV. 12, 1935. J, D, KRE|5 2,020,948

DISTILLATION SYSTEM Filed Jan. 6, 1953 3 Sheets-Sheet 2 NOV. 12, 1935. J, D. KRElS DISTILLATION SYSTEM Filed Jan. 6. 1953 3 Sheets-Sheet 3 Patented Nov. 12, 1935 UNITED STATES DISTILLATION SYSTEM Joseph D. Kreis, Cleveland, Ohio, assignor to E. L. Frantz, trustee for "Dry Cleaning Syndicate Application January 6, 1933, serial No. 650,452

19 Claims.

This invention relates to a method of and apparatus for distilling liquids and performing similar operations.

The principal object of the invention is to provide for the distillation of liquids in a more eicient and more economical manner than has heretofore been possible. A further object is to provide for distillation with a minimum loss of energy. More limited objects are to provide for condensation of relatively cool, semi-liquid vapors by the addition thereto of relatively hot vapors and to provide for substantial, although incomplete, condensation of relatively cool vapors by substantial isothermal compression thereof.

Other and more limited objects will become apparent from the following description when taken in connection with the accompanying drawings wherein Fig. 1 is a central vertical section taken through a distillingmachine embodying my invention; Fig. 2 4is a horizontal section taken therethrough; Fig. 3 is a horizontal section at the level of the pump S; Fig. 4 is a detail section of the oat valve M, identical in construction with that N and Fig. 5 is an enlarged detail section through the valve assembly D.

The construction of the machine which'I prefer to employ in carrying out my improved method will now be described with reference to the drawings and the method will be-'set forth in connection with the operation of the machine, and particularly set forth in the claims.

The reference characters K and V indicate storage tanks above and below the distilling mechanism and adapted for receiving the liquid to be distilled and the distillate respectively. 'Ihe distillingmecha-nism proper comprises an outer cylindrical wall Ill and an inner cylindrical wall II joined by downwardly sloping bottom wall I2 and dening between them a. receptacle C adapted to contain liquid at substantially `room temperature. "The receptacle or chamber C is covered by a top wall or dome I3 affording a gastight seal. Within the inner cylindrical wall II is a layer of insulating material I4 within which is a cylindrical wall I5 deiining a chamber A adapted to receive and conduct hot vapors. 'I'he lower end of the wall I5 is connected in sealing relation with the plate I6 which is connected to Y a lower plate II by a cylindrical wall I8. Sealed to the bottom of the plate I1 is a. bottom I9 completing a receptacle adapted to receive liquid to be distilled and to allow settling of any sludge therefrom. A closure 20 affords access for re moving such sludge.` Extending between the plates I6 and I1 are a plurality of tubes 2I and ber A.

22, the inner tube 22 being considerably larger than those 2I whereby to allow for return circulation of liquid which has iiowed upwardly by reason of the high temperature of the liquid therein. A steam inlet T communicates through 6 the wall I8 whereby to supply steam to the space surrounding the tubes 2I and 22.

At the lower end of the wall I5 is an inwardly and upwardly extending ange 23 adapted to guide the heated vapors toward the center of 10 the conducting passage or chamber 'A and to aiord a trap for relatively non-volatile portions of the liquid evaporated which may condense on the walls I5 and run downwardly. An outlet (not shown) from the space between the flange l5 23 and the wall I5 may be provided.

Liquid to be distilled passes downwardly from thelstor'age tank K through a pipe L and hand operated valve-I to a iioat valve M which communicates by means of a pipe 24 with the cham-v 20 ber C and is vented by a pipe 25 communicating with the interior of the chamber C'above the liquid level. Liquid from the tank K passes also directly into a passage Q and thence downwardly through a pipe R to a second oat valve N from 25 which it passes through pipe O to a; heating cham- The oat valve N maintains a constant level in this chamber and is vented by a pipe 26 extending to the interior of the chamber A above the liquid level. There is also a. connec- 30 tion between the pipe L and the oat valve N through a hand operated valve J and pipe P to a circular radiating tube 21, provided with iins 28, and a connecting pipe 29. A pipe 30 connects the pipe 2l to an agitating valve assembly 35 D which is positioned with its outlet within the chamber C and slightly below the liquid level.

At the top of the storage tank K is a motor 3| mounted in any suitable manner and provided with a shaft 32 extending downwardly through 40 the storage tank and connected in driving relation ,with the rotor of a compression pump S.

l The said rotor is positioned within the passage Q and separated therefrom by a thin wall 33 composed of heat conducting material preferably metal'. The inlet for the pump S is a passage 34 communicating with the chamber C. The outlet of the pump communicates by a narrow port 35 with a circular chamber E. It will be noted that the passage Q substantially entirely surrounds the pump whereby to facilitate delivery of the heat of compression to the liquid to be heated.

The chamber E delivers to a mixing chamber B at the narrow inner edge thereof. A narrow I5 and the lower edge of the wall 31 defining the chamber E a'ords ingress for hot vapors to the mixing chamber B. Insulation 38 is provided for preventing the heat from the chamber A from being transferred to the mist in chamber E and the liquid in passage Q. A Vcuri/ed corrugated plate U is provided in the mixing chamber B for guiding the mixed vapors upwardly into contact with the inner wall 39 defining the passage Q.` The plate U is provided with perfrations 40 adaptedl to drain condensed liquid therefrom downwardly upon the bottom of the chamber B.

Extending downwardly from the chamber B are a plurality of tubes G each of which is provided with a twisted ribbon 4I adapted .to guide the liquid against the wall of the tube whereby it will tend to give up its heat to the vapors in the chamberfC and to the liquid therein instead of dropping directly through the tubes as would be the case if the ribbon were not provided. Sealed toy the bottom wall I2 in any suitable manner is an annular member 42 defining with the wall I2 a chamber H adapted to receive the distillate.

A tube 43 communicates with the interior of the chamber H above the bottom thereof and the valve D whereby to provide for,withdrawing any uncondensed vapors from said chamber. The valve assembly D is provided with adjusting means 44 and 45 for adjusting the outlet openings for liquid from the pipe 30 and vapors from upper and lower storage chambers to a minimum and to this end is provided, in each said tank, a float 48 which covers most of the surface thereof and is provided with edge flanges 49 and 50 dening a receptacular space 5I. One or more perforations 52 are'provided in the flanges 49 and 50 for the purpose of admitting to the receptacularl space `5I any excess of water or other iloatlng liquid which may then be drained olf through a pipe 53 which communicates with the space 5I and is coiled whereby to provide for vertical movement.

In operation the liquid to be distilled passes from the upper storage chamber K through passages` Land It to the iloat valves M and N and from these valves into the evaporation chambers A and C, a constant level being maintained therein by the oat valves as indicated. 'While the supply to the float valve N may be through the pipe P past the valve J, it will normally be supplied from the storage chamber K through the passage Q and pipe R whereby the heat of compression from the pump S may be used for preheating the4 liquid which is to be converted into vapor by boiling at substantially normal boiling temperature.

Under the influence of the pump S vapors are drawn from the cold evaporation f chamber' C and a partial vacuum is created over v 2,020,948 passage 36 between the upper edge of the wall ployed, the pump need only handle a volume equal to the increase due to evaporation and the pressure may remain normal Inasmuch as the vapor volume is greatly reduced by the pump, in the present machine operating on carbon tetrachloride to about four volumes in a thousand,

there is not the corresponding pressure increase on the other side of the pump but only about normal atmospheric pressure, in the present machine about 762 mm. Hg. The pump S not only 1o produces circulation of the vapors from the chamber C but tends to condense them to liquid and in so doing to liberate an amount .of heat substantially equal to the latent heat of vaporization of the vapors passing therethrough. The heat 15 of compression thus liberated tends to oppose condensation but most of it is transferred through C the walls surrounding theA pump to the incoming liquid in the passage Q. The removal is not quite perfect and the result is that the vapors from the 20 chamber C pass into the chamber E in the form of a fine mist, the minute globules of which remain suspended and do not'coalesce to form a liquid, although possessing substantially none of the latent heat of vaporization. That is, the mist 25 possesses most of the characteristics of a liquid, merely being so finely divided andY suspended as to resemble a vapor. This mist is delivered from the chamber E into the chamber B at a point immediately underneath the chamber E where ii 3o is mixed with vapors at substantially the normal boiling point of the liquid, produced in the cham-v ber A by boiling the liquid in the lower portion thereof through the action of steam supplied through the pipe T or by any other suitable heat- 35 ing means. As the hot and cold vapors mix, they begin to roll upwardly over the curved perforated plate U. The addition of the hot vapors to the mist entering the chamber B from the chamber E causes substantially complete condensation of 40 bot-h vapors and coalescence of the globules to form a liquid. (It is my belief that the mist" in the chamber E consists of very small globules of liquid separated from each other by a distance only slightly greater than would result in coales- 45 cence and that thesev globules are suspended in a small amount of vapor or possibly air remaining in the system, and that as soon as the hot vapors come into contact therewith they, so to speak, begin to condense upon the colder globules forming o thereon a thin lm and giving up their latent heat of vaporization to the globules, both of which tend to increase theirsize.` This results in overcoming the balance required for suspension a and the globules coalesce to form a liquid which 55 flows through the perforations in the plate U and thence downwardly throigh the pipes G). The vacuum created by the pump S causes liquid to be drawn into the chamber- C through the valve assembly D as well as vapors from the chamber 00 H. These produce surface turbulence of the liquid in the chamber C with lthe result that evaporation at room temperature proceeds much more rapidly than would be the case if the surface were not agitated. Where the vacuum is great G5 enough to cause the liquid in chamber C to boil at normal temperature, the surface agitation may optionally be dispensed with.

In evaporating at normal temperature the liquid in the chamber C absorbs from its surroundings the amount of heat required to convert thc liquid into the vapor. This heat is substantially entirely abstracted at the pump by theincoming liquid in the passage Q and carried to the body of liquid tobe evaporated at boiling point.

The result is that the mist in the'chamber E is practically without any latent heat of vaporization. The hot vapors from the evaporation chamber A possess the latent heat of vaporization together with the sensible heat required to elevate the temperature to normal boiling point. The amounts of liquid evaporated in the two chambers are so selected that the latent heat content ofthe hot vapors are approximately equal to the heat required to elevate the mist in the chamber E, which, at that point is at 'substantlally room temperature, to the boiling point.`

It will thus be seen that if the hot vapors lose their latent heat, that is, condense to a liquid,

there will be just sumcient heat inthe system to result in a liquid at the boiling point. It has been observed in practice that the hot vapors mix with the cold vapors, their latent heat is given up, both vapors condense, and a liquid at substantially the boiling point is formed in the chamber B. This liquid is carried downwardly by the pipes G where it gives up its sensible heat to the liquid in the chamber C, the result being that the distillate is delivered to the compartment H and nally to the lower storage tank V at room temperature. l

The thermodynamic relations involved may possibly be better understood by reference to a specific example, assuming the Vpresent machine to be operating on carbon tetrachloride, in

a given time :i: pounds of liquid will be evaporated in the cold evaporation chamber C and y pounds from the `hot evaporation chamber A.

Since the latent heat of vaporization of C014 at 64 F. (the working temperature in the chamber C) is 91.6 B. t. u. per pound, 91.6 :z: B. t. u. will be abstracted from the surroundings', principally from the liquid in chamber C. nearly this amount of heat will be removed at the pump S 40 and transferred to the liquid in the passage Q.

` There must be supplied to the hot vaporv chamber AA'v enough heat to elevate the y pounds of liquid to the boiling point and to supply the latent heat of vaporization. 'I'his is supplied in part by the heat of compression of the pump. The amount of heat required to raise y pounds of liquid from 70 F. to 170 F., theboiling point, will be (100) (.192) y and the amount of heat required to vaporize it at 170 F. will be 83.7 y

B. t. u. Since, as has already been `stated, it is desirable that the latent heat of vaporization of the hot vapors should be equal to the heat required to raise the compressed cold vapors from room temperature to boiling point it appears that the relative values of :i: and y will be given by the equation (.132 being the specific heat of the cold vapors): (100) (.132) :z:=83.7 y. Solving the equation, =6.34 y. Therefore, when one pound is evaporated in the chamber A, 6.34 50 lbs. should be evaporated in the chamber C. The above figures are rough, no allowancabeing made for change of specific heat with temperature or for the semi-liquid state of the vapors in the chamber E, but they agree fairly well with the actual relations found to exist in practice. The

sensible heat of the liquid condensed in B must be given up to the liquid and vapors in the chamber C and this is done as it ows down the 0 tubes G. This heat amounts, for each pound of u hot vapors, to (7.34) (100) (.192) or 141 B. t. u. @As shown above, the heat abstracted from the liquid in chamber C due to cold evaporation is 91.6 :n or 580 B. t. u. The deciency of 439 5n B. t. u. is supplied in part from the passage Q by leakage through the wall into the chamber and in part by leakage through the outer wall of the machine. The latter lags a little with the result that the temperature in the chamber C runs a few degrees below room temperature. 5

Obviously the amount of liquid evaporated by boiling may be regulated by varying the steam supply while that evaporated from the chamber C may be controlled by the valve D or by the motor speed. It will therefore be easy to se- 10 cure a proper balance between the two evaporation chambers.

By normal boiling point is to be understood, wherever it appears in this specification and claims, the boiling point temperature un- 15 der usual atmospheric pressure, that is, pressures of the order of 30 inches of mercury. By normal temperature or room temperature, as used in this specification and claims, is to be understood that range of temperatures which is usual- 20 ly encountered in temperate climates, that is, temperatures of the order of from to 90 F.

Having thus described my invention, what I claim is:

1. 'Ihe method which comprises producing a 25 mist by substantially isothermal compression of vapors of a substance at a temperature below the normal boiling point of the substance and producing coalescence of the minute globules of the mist by the addition of saturated vapors of 30 the substance at substantially the normal boiling temperature.

2. The method which comprises producing a mist by substantially isothermal compression of vapors of a substance at a temperature below 35 the normal boiling point of the substance and producing coalescence of the minute globules of the mistby the addition of saturated vapors of the substance at substantially the normal boiling "temperature, the hot vapors being added in such 40 proportion that the latent heat of vaporization thereof is approximately equal to the heat required to elevate the mist to t e normal boiling point.

3. In a device of the class described, a cold 45 evaporation chamber, means for supplying liquid thereto, means for compressing vapors therefrom, means for removing the heat of compression of said' vapors, a hot evaporation chamber. means for supplying liquid thereto, a mixing chamber, and means for causing the compressed cold vapors and .the.hot vapors to enter said mixing chamber and a liquid outlet from the latter. l

-4. In a device of the class described, a cold evaporation chamber, means for supplying liquid thereto, means for compressing vapors therefrom, a hot evaporation chamber, means for supplying liquid thereto, means for transferring the heat of compession of said cold vapors tothe liquid in said hot evaporation chamber, a mixing chamber, and means fer causing the compressed cold vapors and the hot vapors to mix therein and a liquid outlet from said mixing chamber.

5. In a device of the class described, a cold evaporation chamber, a hot evaporation chamcber, means for supplying liquid to said chambers, means for compressing vapors from said cold evaporation chamber just short of enough to produce liquefaction, means for removing the heat of compression of said vapors, a mixing and condensing chamber, means for causing the va pors from said evaporation chambers cto mix therein and a liquid outlet from said mixing chamber.

6. In a device of the class described, a cold evaporation chamber, a hot evaporation chamber, means for supplying liquid to said chambers, means for compressing vapors from said cold evaporation chamber just short of enough to produce liquefaction, means for removing the heat of compression of said vapors, a mixing and condensing chamber, means for causing the vapors from said evaporation chambers to mix therein and a liquid outlet from said mixing chamber, means being provided for transferring the heat of compression of said cold vapors to the liquid in said hot evaporation chamber.

7. In a device ofthe class described, a cold evaporation chamber, means for compressing vapors therefrom just short of liquefaction, means for removing the heat of compression of said vapors, a hot evaporation chamber, a mixing chamber, means for causing the compressed cold vapors and hot vapors to enter said mixing chamber, a liquid outlet from said mixing chamber, and means for transferring the sensible heat of the liquid from said mixing chamber to said cold evaporation chamber.

8. In a device of the class described, a cold evaporation chamber, means for compressing vapors therefrom just short of liquefaction, means for removing the heat of compression of said vapors, a hot evaporation chamber, a mixing chamber, means for causing the compressed cold vapors and the hot vapors to enter said mixing chamber, a liquid outlet from said mixing chamber, and means for transferring the sensible heat of the liquid from said mixing chamber to said cold evaporation chamber, the relative proportions of liquid evaporated from said hot and cold evaporation chambers being so adjusted that the latent heat of vaporization of the hot vapors is` substantially enough to elevate the cold vapors from room temperature to the boiling point.

9. In a device of the class described, a cold evaporation chamber, means for maintaining the same partially filled with liquid, means for agitating the surface of said liquid, means for compressing vapors from said chamber to a point just short of liquefaction, means for removing the heat of compression of said vapors, a hot evaporation chamber, means for elevating liquid therein to 'boiiing'temperatura a mixing chamber, means for causing the compressed cold vapors and hot vapors to mix therein, andfmeans for conveying liquid from said mixing chamber.

10. In a device of the class described, a cold evaporation chamber, means for maintaining the same partially lled with liquid, means for agitating the surface of said liquid, means for compressingvapors from said chamber to a point just short of liquefaction, means for removing the heat of compression of said vapors, a hot evaporation chamber, means for elevating liquid produced by boiling to be brought toge er 5 whereby to produce liquefaction of both "port ons of the vapor. il]

12. The method or distilling uquid which com f prises the steps of evaporating a portion ot such liquid at room temperature, compressing the va- 10 pors thus created just short of sufllcient to produce liquefaction, removing the heat of compression, evaporating another portion of such liquid by boiling and then causing said compressed vapors andthe hot vapors produced by boiling to`15 be brought together whereby to produce liquefaction of both portions of the vapor, the relative proportions of liquid evaporated at normal temperature and at boiling point being such that the latent heat of vaporization of the hot vapors 20 is substantially equal to that required to elevate the cold vapors from room temperature to boiling point.

13. The method of distilling liquid which comprisesv the steps of evaporating a portion of such 25 liquid at room temperature, compressing the vapors thus created just short of suiilcient to produce liquefaction, removing the heat of compression, evaporating another portion of such liquid by boiling and then causing said com- 30 pressed vapors and the hot vapors produced by boiling to be brought together whereby to produce liquefaction of both portions ofthe vapor, the amount of liquid evaporated at the boiling point being such relative to the amount evapo- 35 rated at room temperature that the hot vapors will produce substantially complete condensation of the hot and cold vapors when they are brought together.:

14. The method of distilling liquid which com- 40 prises the steps of evaporating a portion of such liquid at room temperature, compressing the vapors thus created just short of suflicient to produce liquefaction, simultaneously removingthe heat of compression, evaporatinganother por- 45 tion of such liquid by boiling and then causing said compressed vapors and the hot vapors produced by boiling to be brought together whereby to produce liquefacton of both portions of kthe vapor, the amount of liquid evaporated at the 50 boiling point being such relative to the amount evaporated at room temperature that the hot vapors will produce substantially complete condensation of the hot and cold vapors when they are brought together.

15. The method of distilling liquid which comprises evaporating a portion thereof at approximately room temperature whereby to produce cold vapors and another portion thereof at its boiling point whereby to produce hot vapors, so compressing the cold vapors slightly less than enough to produce liquefaction, removing the heat of compression therefrom, andlcausing condensation of both portions of vapor by bringing the hot vapors into contact with said compressed '651l vapors. y .l

' 16. The method of distilling liquid which cornprises evaporating a portion thereof at approximately room temperature whereby to produceA cold vapors and another portion thereof at its 70 boiling point whereby to produce hot vapors, compressing the cold vapors slightly less than enough to produce liquefaction, removng the heatof compression therefrom, causing condensation of both portions of vapor by bringing the hotva- 7s Dors into contact with said compressed vapors,

and then causing transfer vof the sensible heat from the condensed liquid. to liquid yet to 'be distilled whereby to assist in maintaining the latter at approximately room temperature.

17. The method of distilling a liquid which comprises steps of evaporating al portion of said liquid at approximately room temperature whereby to produce. cold vapors, compressing such liqproximately equal to the heat required to elevate the temperature of the co pressed vapors to the boiling point. s

181A device for the continuous distillationV of liquids which comprises a closed system provided with inlet and outlet means for the liquid to be p distilled, a pair of evaporation chamber'sand a mixing chamber each being in communication l with said inlet means and a mixing chamber communicating with said evaporation chambers and .nuxing chamber and one of said evaporation i chambers for compressing vapors therefrom, Y

means for removing the neat of compression from said vapors before they are delivered to said mixing chamber, and means forevaporating liquid in said other evaporation chamber at its boiling point.

19. A device for the continuous distillation o1' liquids which comprises a closed system provided f with inlet and outlet means for the liquid to be distilled, 'a pair of evaporation chambers and a mixing chamberv each being in communication with said inlet means and a mixing chamber comymunicating with said evaporation chambers and said outlet means, means interposed between said mixing chamber and one of said evaporation chambers for compressing vapors therefrom,O

means for removing the heat of compression from said vapors before they are delivered to said mixing chamber, and means "for Aevaporating liquid insaid other evaporation `chamber at its boiling point; said outlet means passing through the liquid in said rst mentioned evaporation chamber whereby to deliver the sensible the condensed lquid thereto.

f JOSEPH D. KREIS.

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