US1743289A - Apparatus for distilling liquids - Google Patents

Description

Jan. 14, 1930. w. E. SANGER APPARATUS FOR DISTILLING LIQUIDS Filed July 25, 1925 Patented Jan. 14,1930

UNITED STATES PATIENT OFFICE 'WALTEB E.,SANGEB, OF CHICAGO, ILLINOIS; UNION TRUST COMPANY, OF DETROIT, MICHIGAN, EXEC'UTOR OF THE SAID WALTER E. SANGER, DECEASED, ASSIGNQR TO OSCAR H. WURSTER .Application filed'July 23,

This invention relates to an apparatus for distilling various liquids, and especially those which show a tendency to partially decom ose directly or alone at normal pressure. uch liquids are distilled in a partial" Vacuum whereby the boiling point of the liquids is lowered in accordance with the degree of exhaustion. The improved apparatus is particularly adapted for distilling crude glycerine, but'the invention is not limited to this particular substance.

The object of the invention is to provide an improved apparatus for. performing distillations of the nature referred to above.

The present invention may be considered in some respects as an improvement upon the invention disclosed in my prior Patent No. 1,452,617, granted April 24, 1923.

' The present invention is exemplified in the combination and arrangement of parts shown in the accompanying drawingand described in the followingspecification and in the steps of the process disclosed therein.

In the drawing, the figure is a diagrammatic elevation, with'parts in section, showing one form of apparatus comprised in the present invention.

As shown in the drawing, the numeral designates a still of the same general nature as shown in my prior patent referred to above. The still is provided with an internal heating coil 11 through which steam or other heating medium may be circulated for evaporating the contents of the still. The still may be additionally heated by an external sourcev in the usual manner if desired. pipe 12 enters the top of the still and is provided with a perforated'spider 13 at the bottom from which heated vapor'is discharged into the glycerine or other liquid within the still to assist in the operation. A ring or coil 14 is positioned near the bottom of the still and is of slightly less diameter than the coil 11. The

erforations for directing fluid discharge therefrom toward the top of the coil 11. Outside the still the ,coil 14 is provided with connections 15 and 16 by which either air'or steam may be introduced into the perforated ring 14. .At the top of the still a second perforated ring 17 1s described in my prior patent.

APPARATUS FOR DISTILLING LIQUIDS 1923. Serial No. 653,074.

' ber 23 and end chambers 24 and 25 separated from one another by heads 26. The cham- "bers 24 and 25 are connected by a series of tubes 27 passing through the central chamber 23. Baflle plates 28 are preferably provided for directing the vapor from the pipe 19 about the tubes 27. The tubes 27 are supplied with vapors at a lower temperature than that of the vapor from the still in a manner to be explained so that the vapor from the still will give up a portion of its heat to the vapor passing through the tubes and in this way a portion of the glycerine will be condensed and pass downwardly into a receiver 29. The uncondensed portion of the vapor from the distilling liquid will rise through pipe 30 and pass through pipes 31 and 32 to a second condenser 33. To eflfeot this operation the valve 34 will be closed and the valve 35'open. The condenser 33 is of the same general construction as a superheater condenser 21 and is provided with pipes through which a cooling medium may be circulated, the medium being supplied by connctions 36. Watermay be used as a cooling medium or oil may be employed and the amount of condensation may be controlled by the temperature of the cooling medium which can be regulated as desired.

The condensate from the condenser 33.

passes through pipe 39 intoa-collector 40. If further condensation is, desired the vapors may pass from the collector 40 through pipe 41 to a third condenser 42 similar to the conthe glycerine, and glycerine of any desiredgravity may be obtained. For example, if a sufiiciently high temperature condensing medium is used it would be possible to obtain glycerine of dynamite grade without further concentration. By the use of successive condensers with decreasing temperature of condensing medium all of the glycerine may be condensed separately, giving varying concentrations of glycerol. In some cases a single condenser 33 in addition to the superheater g condenser 21 will be sufiicient, and in such cases the condenser 42 and its receiver 47 will be omitted.

The various receivers 29, 40 and 47 are arranged to drain into a pipe 50 which is con- 58 nected by means of a pipe 51 to the bottom of a concentrator 52. The opposite end of the ipe 50 is connected through pipe 53 to the ttom of the evaporator 54, there being a syphon bend 55 in the pipe 53 for purposes to be described. Valves 56, 57, 58 and 59 control the pipe connections so that the condensate from the different receivers may be conducted either to the concentrator 52 or the evaporator 54. The concentrator 52 is provided with a heating coil 60 which ma be supplied with steam or other heating medium from any suitable source, and at the upper portion of the concentrator a separate coil or coils 61 is located to which a heating medium may be supplied by connections 62 for superheating the vapor arising from the concentrator. The glycerine in the concentrator will have a relatively high boiling point so that the exhaust steam from the plpe 60 may coil62 in the evaporator 54. The evaporator 54 will be supplied either with water through a connection-63 or with the distillate from the-receiver 47, or perhaps from the receiver 40. This distillate which enters the evaporator throu h pipe 53 will have the larger portion 0% its glycerine condensed therefrom and returned to the concentrator 52 through the pipe 51 so'that the liquid supplied to the evaporator will have only a small percentage of glycerine and is known as sweet water. 7

The vapor from the evaporator 54 may be passed through pipe 65 to the upper portion of the concentrator 52 where it is subjectedto the action of the superheating coil 61 and mingles with the vapor from the concentrator 52. It then passes upwardly'through pipes 66 and 67 to the superheater condenser 21 where under ordinary operation it is further be used for supplying heating medium to the discharged into the crude glycerine to aid in distillation in the manner described in my prior patent.

It will be seen that the exhaust pump 49 operates through the various condensers in series to the top of the still 10. The upper portion of the evaporator 54 and concentrator 52 are connected with the bottom of the still so that the evaporator and concentrator will also operate at a reduced pressure due to the action of the pump, but in actual prac: tice the pressure in the evaporator and concentrator, will be greater than that in the still, the diflterence in pressure usually corre: sponding to a head of approximately ten inches of mercur If the still is operated say under 28 inc es of vacuum, the vapors from the evaporator are at a temperature of steam at approximately 18 inches of vacuum or about 173 Fahrenheit.

, The .liquor in the concentrator is a highly concentrated solution of glycerine and water with some impurities and has a boiling point of approximately 300 Fahrenheit and the vapors passing from the concentrator have a temperature closely approximating this temperature. I find that these vapors from a concentrated solution of glycerine (70 to 90% glycerol) will carry over mechanically.

or through partial pressure an appreciable amount of glycerol, thesevapors after concentration of the same analyzing an average of 3% of glycerine. Heretofore these 0011- densed vapors have been collected as sweet water which yields an inferior product or were re-distilled with the sweet water if that method of disposing of glycerine in sweet water was resorted to. proved process these vapors are not condensed directly but passed to the still in the form of vapors and are used for distilling the crude glycerine contained therein. With this arrangement more glycerine is obtained in a purer form, such as dynamite glycerine.

I find that by providing superheating coils (through which there is passed steam ata' temperature in excess of 360 Fahrenheit) in the upper part of the concentrator and passin both the vapors from the evaporator an the concentrator around these coils, that the resultant mixture of these vapors enters the superheater at a considerably higher temperature than-if the vapors of the 'sweet water evaporator are utilized and perature there is a smaller difierencein temperatu're between the vapors passing/from the still and the injection vapors so that less glycerine is automatically condensed in the superheater, and that which is condensed is of a higher degree of concentration.

By the use of successive condensers, as described with decreasing temperature of condensing medium, all .of the glycerine may be condensed separately, giving various concentrations of glycerol in the diiferent receivers. The piping of the return lines from the various receivers is so arranged that any part of the distillate may be returned to the concentrator or to the sweetwater evaporator, as desired. As previously pointed out, the sweet water evaporator 54 will be un der a vacuum of; approximately 18 inches, while the sweet water receivers are more thoroughly exhausted and are under a vacuum of about 28 inches. In order that the sweet water will run by gravity from the receivers to the evaporator without danger of reverse flow it is necessary that there be a considerable difference in'level or head between the bottom of the receivers and the level of the liquid in the evaporator. I find that by using a siphon 55 in the receiver return line, as shown in the drawing, less space is required between the bottoms of the receivers and the top of the evaporator, since it is always necessary to lift a head of water to the top of the siphon before there is danger of return flow from the evaporator to the receiver. This reduces the height necessary for the equipment, allowing it to be installed in buildings with lower ceilings. To further guard against any chance of return flow of the sweet water from the evaporator through the receiver and through the exhaust pump where it would be lost, a check valve 68 may be placed in the line 53 to prevent reverse flow therein. Since the same condition may exist in the connection between ,the concentrator andthe receivers, a check valve 69 is also placed in the line 51.

In the distillation of crude glycerine the coils in the still become coated with material known as foots which is baked on the coil,

thus interfering with the transfer of heat. This foots is readily soluble in hot Water and .by providing a perforated pipe 17 over the top of the heating coil and of substantially the same diameter as the heating coil, hot water may be run over the heating coil from this open pipe and the coil may thus be cleaned. and kept in a high degree of eiiiciency. The same result may be obtained by running cold water through the perforated coil 17 and keeping a small amount of steam turned on on the closed coil in the still. I find further that by placing a. perforated coil 14 inthe bottom of the still having connection for steam and air that a violent splashing may be obtained and the still may be thoroughly cleaned.-.

Assuming that, for instance, dynamite glycerine is to be produced, the crude glycerine is fed automatically into the still 10 to which external heat is preferably supplied.

Air is now exhausted from the entire apparatus by means of the vacuum pump 49. The evaporator 54 contains water orjis lled with sweet water from a previous distillation. This water is heated by the coil 62and under the reduced pressure the sweet water in the evaporator passes out through pipe into i the concentrator '52 around the superheater coil 61 and into the superheater condenser 21. Here it passes through the tubes 27 and may be further superheated by the vapors of glycerine and steam which pass upwardly from the still through pipe 19 and pass around the condenser tubes 27 Asthe sweet water vapor which passes from the evaporator is saturated steam produced in a vacuum, its

temperature is considerably below 212 Fahrenheit. The vapors passing from the liquid in the concentrator are produced under a vacuum, but due to the high concentration of. glycerine therein they have a temperature considerably in excess of saturated steam at the reduced pressure, and also partly due to the fact that these vapors carry some glycerol and glycol. The vapors from the evaporator are heated by the vapors passing from the glycerine in the concentrator and the mixture of vapors from the evaporator and concentrator are both superheated by the superheater coil 61. Accordingly there may be a difference in temperature between the va ors from the still and the vapors passing rom the concentrator, and the mixed vapors from the concentrator being cooler than those from the still may act as a condensing medium and a part of the glycerine will be condensed in the superheater condenser 21. The amount of glycerine so condensed is controlled by the amount of superheating done in the concentrator.

If the vapors from the concentrator are superheated to a temperature in excess of the temperature of the vapors from the still none "of the vapors from the still will be condensed but on the contrary the vapors from the still will be superheated. If the vapors from the ture below the temperature of the vapors from the still, some of the vapors from the still will be condensed and it will thus be amount of evaporating surface provided in concentrator are superheated toa temperathe evaporator and concentrator and the temperature which is there maintained. The

pors thus injected cause the hot glycerine to distill over througn the pipe19, as stated. It will be noted that ,the pipe connection 12-.extends downwardly through the still from the topthereof in the arrangement shown so that the steam contained in pipe 12 may be further superheated by the vapors of the distill- ,ing glycerine as they pass upwardly through the still on their way through the pipe 19. The part of the glycerine condensed in the condenser 21 drops into the receiver 29 from which it passes through pipe 51 into the con-' centrator 52. Most of the water vapor which is carried along with glycerine vapor does not condense in the superheater condenser, but passes along with the remaining uncondensed glycerine through pipes 30 and 32 to the condenser 33. If the condenser 33 is the only additional condenser employed, then the remaining vapor is condensed and drops into receiver and from there passes through the pipe connections shown either to the concentrator 52 or the evaporator 54. If the additional condenser 42 is employed, the portion of the vapor not condensed in 33 is condensed in 42 and passesthrough the receiver 47 to the pipe connection 50, and thence to the concen trator or the sweet water? evaporator where the glycerine is finally concentrated to a finished product.

Perforated pipes 70 and 71 are provided for injecting open steam into the lower part of the concentrator 52 and evaporator 54, respectively. If by any cause an impurity such as trimethylene-glycol is run into the concentrator with the glycerine, this substance may be distilled from the concentrated solution of the glycerine containing this impurity by injecting open steam through the perforated pipe 70 which is located below the level of the liquor in the concentrator. The open pipe 1 in the evaporator may be used in a similar manner. I

In the distillation of chemically pure'glycerine the process is the same as that described for distillation of. dynamite glycerine, except that fresh water in place of sweet water is used for generating the vapor discharged at the bottom of the still. I find that'in making a high grade of glycerine sweet water is unsuitable because some of the impurities of the sweet water are carried over into the still from where they are distilled over. and

collectpartly in the concentrator making it impossible at times to secure a chemically pure grade to meet the requirements of the United States Pharmacopoeia. In carrying out the process with fresh water the 'water is supplied to the evaporator throughout the I said still.

which is condensed is held in the receivers until completion of distillation when they are evaporated in any suitable vessel.

It will, of course, beobvious that my process is not limited in its application to the distillation of glycerine, but that the same may be used in distilling other liquids which'are distilled by steam or water vapors, and particularly such liquids which show a tendency to decompose when distilled at partial or normal pressure.

It will be apparent that the superheater coil 61 could be located in the evaporator 54 instead of concentrator 52. In this case the pipe 65 would connect with the concentrator at the top thereof and enter the evaporator below the superheater coil and the pipe 66 would lead the superheated vapors from the top of the evaporator 54 instead of from the concentrator, as illustrated. The two de vices 52 and 54 are very similar in construction and operation and in fact either could be called an evaporator or a concentrator. The terms have been applied in the manner used above merely for convenience and because the vessel 52 is commonly supplied with a more concentrated solution of glycerine.

It should be notedvthat my invention is not limited strictl to the various details of the apparatus which has been particularly described, except as panying claims.

I claim I pointed out by the accom- 1. Distilling apparatus comprising a still, v

condensate of saidvapors into said evapo-. rator, means for closlng conductlng means to exclude said condensate from said evapo rat'or, means for supplying fresh water to said evaporator so that said fresh water may be vaporized therein to produce fresh water vapors, and means for conveying said fresh water vapors to said still comprising a suitable conduit connecting said evaporator with 2. In a distillation unit, the combination with astill of a sweet water evaporator, a sweet water receiver above said evaporator for receiving condensed vapor from said still, a conduit extending from said receiver to said evaporator, and a check valve in said conduit preventing the return of the sweetwater to said receiver.

3. In combination, a still, a condenser for vapors from said still, a receiver for the condensate from said condenser, means for exhausting air from said receiver, a eoneen trator positioned below and having a c011 duit connection with said receiver, and a check valve in said conduitfor preventing return flow ot'liquid from said concentrator to said receiver under the influence of the vacuum in said receiver.

4. In distilling apparatus, the combination with a still, of a concentrator in the upper part of which there is a superheating coil, means for condensing vapor from said still and directing the condensate to said concentrator, means separate from said superheating coil for heating the condensate in said concentrator to dispel vapor therefrom, and a conduit opening into said concentrator above said superheating coil, said conduit being connected to said still to return said vapor to said still after it has passed said superheater.

- 5. Distilling apparatus comprising a still, a condenser connected with said still, a concentrator, a liquid conduit through which condensate passes from said still to said concentrator, heating means associated with said concentrator, a vapor conduit connecting said concentrator and still through which vapor may be passed to said still, and a superheater for said vapors located near the top of said concentrator. I

6. In a distillation unit, the combination with a still, of an evaporator, a water line connected to said evaporator, a conduit connecting saidevaporator with said still, and

means interposed in said conduit for heating the vapor from said evaporator before itenters said still.

7. In apparatus for distilling glycerine, the combination of a still, a condenser connected with the upper portion of the still,.an evaporator arranged at alower level than said condenser, means for exhausting air from said condenser, and a pipe line connecting said condenser with said evaporator arranged to permit gravity flow of condensate from the condenser to the evaporator, said pipe line having therein an upward bend constituting a siphon at the upper end adjacent the condenser, and means for independently heating the still and evaporator.

8. Distilling apparatus comprising a still, a series of condensers connected with said still for condensing vapor therefrom, a concentrator having a conduit connecting one of said condensers for receiving condensate therefrom, an evaporator having a conduit connecting another of said condensers for receiving the condensate in the form of sweet-- water therefrom, and means for introducing open steam near the bottom of said concentrator, and of said evaporator.

9. Distilling apparatus comprising a still, means for introducing vapor into said still, a superheater condenser having a pair of conduits associated for heat exchange, one of said conduits being connected with said still for passing vapors'to said still, the second of said conduits being connected with said still to receive the vapors therefrom, and means for superhfeating the vapor passing through said first-named conduit prior to its passage through said superheater condenser.

10. In apparatus for distilling liquids, the combination of a still, a condenser connected with the upper portion of said still, an evaporator arranged ata lower level than said condenser, means for exhausting air from said condenser, and a pipe line connecting said condenser with said evaporator arranged to permit gravity flow of condensate from the condenser to said evaporator, said pipe line having therein an upward bend constituting a siphon, and means for heating said still and evaporator.

11. In distilling apparatus the combina-- condensers to said evaporator, said pipe linen having therein an upward bend constituting a'siphon, and means for heating said still and I evaporator.

12. In distilling apparatus, the combination of a still, a condenser connected with the upper portion of sa1d still, a recelver below said condenser, an evaporator arranged at a lower level than said receiver, means for exhausting air from said receiver, and a-pipe line connecting said receiver with said evaporator arranged to permit gravity flow of condensate from said receiver to said evaporator, said pipe line having therein an upward bend constituting a siphon, and means for heating said still and evaporator.

In testimony whereof I have signed my name to this specification on this 18th day of July, A. D. 1923.

' IVALTER E. SANGER.

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