US1757108A - Apparatus for condensing hydrocarbon vapors - Google Patents

Description

1925 2 sneensmsnw i May 6, 1930. J E, BEL

.APPARATUS FOR CONDENSNG HYDRQGARBON VAPORE Filed Jan. 22,

May 6, 1 930. J. E. BELL APPARATUS FOR CONDENSING HYDROCARBONy VAPORS 2 Sheets-*Sheet Filed Jan. 22V, 1925 l V? ATI'ORNEY Patented May 6, 1930 UNITED STATES,

PATE-NT ori-lcs JOHN E. BELL, DECEASED, LATE OF BROOKLYN, NEW YORK, BY LOLA R. BELL, EXECU- TRIX, OF BROOKLYN, NEW YORK, ASSIGNOR T SINCLAIR REFINING NEW YORK, N. Y., A CORPORATION OF COHPANY, 0l'

APPARATUS FOR CONDENSING HYDROCARRON VAPORS .Application mea January 2a, 192s. yserial 1ro., 3,986.

"ing the condensed distillates from stills in which hydrocarbon oils are subjected to dis- 5 tillation.

In condensing and cooling the vapors and distillates from oil stills, heat is abstracted from the hot vapors escapin from the still to cool and to condense t e ist-illed vapors, 1o and heat is further abstracted from the condensed distillate to cool it to a final temperature below the temperature of condensation.

The distilled roducts escaping from oil stills always inclu e, although in varying amount, some fixed gases. In the methods hitherto generally employed, the sensible heat of coolingr water has been used to effect the cooling and condensation of the oil vapors, and the cooling and condensing operation has been carried out in a sin le receptacle so that as lcondensate formed urther cooling and condensation involved heat transfer to a mixture of vapors, liquids and gases. Due to the presence of fixed gases, even the final cooling of thecondensed distillate is commonly carried out while the distillate is admixed with gases, but there are several difficulties incident to the transfer of heat from such mixtures as well as mechanical difficulties involved in handling such mixtures. In the methods hitherto used, it has been necessary to discharge the cooling water from the condenser at relatively low temperature and to employ relatively large volumes of cooling water to maintain the desired low final temperature. Moreover, the cooling ofthe condensed distillate to the desired final temperature is usually the factor controlling the amount ofcooling water employed andthe amount of heat transferringV surface required, so that it has been impossible to realize the full benefit from other economies effected in cooling and condensing the vapors; and even where the temperature of the vapors enterin the condenser has been lowered it has not geen possible to obtain an entirely. corres nding decrease in the amount of cooling water employed due to the fact that the tem erature difference between the vapors an cooling waterris alsov lsecond coolin reduced so that the heat transfer is thereby retarded.

Among the objects of the present invention are to provide an improved apparatus for condensing and cooling the vapors and distillates from oil stills in which the difiicult-ies incidentV to the absorptionl of heat from mixtures of gases, vapors and liquids, or of gases and liquids are overcome or minimized, in which an improvement in the econom of cooling Water employed'is effected wit out sacrifice as to the final temperature of the condensed distillate, and which enables fulladvantage to be taken of improvements in the general efliciency .and economy of the cooling and condensing operation when practiced in conjunction with methods or in a paratus in which an initial coolin of t e vapors from the still is effected be ore they enter the condenser proper.

According to the present invention, the oil vapors from the still are cooled and condensed, the fixed gases and-condensed distillate are then separated, and the separated condensed distillate is subjected to a further cooling operation after `separation of the fixed gases, whereby the eiiiciencyf and economy of the combined cooling and condensing In one way of operating the appxaratus. of i the invention,.the hot vapors from t e still are first cooled and condensed by `heat 'exchange with coolin water, the fixed gases and condensed disti late are then separated, the se arated condensed distillate is then brougiit in heat exchanging relation with cooling water, and cooling Water is passed from the operation to the 'first cooling and con ensing operation. The condensed distillate is thereby cooled to the desired final temperature in an improved way, while the water discharged from this iiscoolmg operation is available at a tem rature suitable for use as a coolingA m ium i in the first cooling and condensing operaf" tion. A lower final temperature of the eondellSed distillate may thus be Obtained Withthe. same amount of cooling water or the same final temperature may be obtained with a reduced amount of cooling water, While at the same time the burden of cooling the condensed distillate tothe desired final temperature is removed, in large part,`from the main condenser so that less cooling vwater may be employed therein. Due to the increased eiliciency of the operation of cooling the condensed distillate when it is carried out subsequent to separation of the fixed gases, a marked economy in overall consumption of water may be obtained. The main cooling and condensing of the hot vapors from the still ma be carried out in much the usual way, an in a condenser of ordinary construction, although the amount of cooling water employed and the size of the condenser may be materially reduced.

It is advantageous to employ all of the cooling water in the second cooling treatment and toemploy all of the cooling water dischar ed from the second cooling treatment in the rst cooling and condensing operation as in this way the maximum cooling and condensation is secured in both stages of the combined operation. Where all of the cooling water is hot vapors from the stil first em loyed in cooling the separated condensed istillate to the desired final temperature and then for cooling and condensing the the amount of cooling water may be regulated to control the final tem y ratureof the condensed distillate and, in a ordinary cases, this will provide more than enough cooling water toV carry out the cooling and condensing operation in the condenser proper. A supplementary amount of cooling water may, however, be supplied to either the second cooling operation, the first -cooling and condensing operation, or to both operations.

The apparatus of the present invention is of special value and application when employed in conjunction with an improved method and aparatus described in an appli- .cation filed 746,471. The made available ctober 29, 1924, Serial No.

(potential econom thereby ue to the reduce temperaf ture of the vapors entering the condenser can thus be more fully realized and a further improvement in etliciency and economy obtained. `In such a combined operation, a sav- Ai of as much as 50% or more may be effected with respect to the cooling water used.

The apparatus of the present invention comprises a still, which may or may not be provided vwith a refiux or fractionating tower, -a condenser communicating-with the vapor s'pace of the still or with theV reflux tower and arran d to discharge into ag'separator, and a coo er connected to the separator so that the condensed distillate is discharged therethrough. The cooler may advantageously take the form of a tubular heat exchanger, arranged for circulation of the condensed dis- /relux tower illustrated is of the tillate through the tubes and for circulation of the coolin water through a jacket about the tubes. he condenser may be of conventional construction and arran ement although a considerably smaller con enser may be employed. Connections are provided to conduct cooling water firstthrough the cooler and then through the condenser. The apparatus of the invention ma also include an evaporative cooler, or con enser, arranged between the main condenser and the still or reflux tower so that the hot vapors from the still first pass therethrough before they enter the condenser proper. Connections may be provided for introducing water to the evaporative condenser either from the. main condenser or from a separate source.

The apparatus. of the present invention l distillate as isV maintained on the condenser to a point beyond the se arator,v but the pressure on the condensed istillate may then be reduced either before it enters or after it leaves the cooler.

The invention will be further described in connection with the accompanying drawings illustrating, somewhat diagrammatically and conventionally, apparatus embodying the in- `vention, but it will be understood that the invention is exemplified by this further description and illustration and is not limited thereto.

InV the accompanying drawings:

Fig. 1 represents in elevation and partly in section a still, condenser and cooler, and

Fig. 2 similarly 'represents a still, evaporative condenser, main condenser and cooler. The still illustrated in the drawing is of the direct fire heatedtype and comprises a shell 1 arranged over a setting 2. Arranged above the still shell is a reflux tower 3. The

v neral construction and operation describe in a prior application filed. April 1, 1924, Serial No. 703,338. The still is provided with 'a charg- -ing line 4, and connection 5 is arran ed at the upper end of the tower for intr ucing feed into the stillthrough the tower. The vapors escape from the top of the tower throu li vapor connections.

Re erring to Fig. 1,.the vapors escaping from the tower on the still enter the condenser through connection 7. In the con-v denser, the va ors, and Icondensate as it is formed, flow own'wardly through a series of pipe coils 8 in indirect heat exchanging relation with cooling water in which they are immersed in the condenser box 9. Cooling water enters the condensing box through connection `10 and overflows therefrom through connection 11'.

The condenser illustrated is the pipe coil type in general use in oil refinin In such a condenser, Vthe condensate as Formed collects in the lower part of the condensing pipes and Hows as a trickling stream therethrough to the discharge outlet. It will be apparent that the area of heat transfer to the condensate is relatively small as compared to the area of heat transfer to the uncondensed vapors and gases and this renders the condenser structure illustrated inefiicient as a cooler of the condensate. In the way in which such condensers are ordinarily employed, the are requiredto condense the vapors an also to cool the condensate, and therein eir'iciency in this latter function renders the entire operation ineii'icient, particularly as compared to the apparatus of the present invention in which these functions are separated to an extent whereb a marked increase in eiiiciency is obtaine In the apparatus of the present invention, the vapors are condensed and are cooled after separation from the iixed gases, whereby the efficiency of the entire operation is im roved, as will appear from the continuing esr1ption.

From the condenser,the condensed distillate and admixed gases are discharged into a separator l2, the fixed gases being discharged upwardly therefrom through connection 13 and the condensate downwardly through connection 14. The condensate flows through connection 14 to and through the cooler 15 where it is passed in indirect heat exchan 'ng relation with cooling water and from which the cooled condensed distillate escapes to a run-down tank or other receiver through connection 16. Cooling water is supplieda to the cooler through connections 17 and 18 and the cooling water discharged from the cooler is circulated to the condenser box through coni nections 19 and 10. Aby-pass connection. 20

is provided for supplying cooling water directly to the condenser and a connection 21 for discharging cooling water from the cooler without passing it to the condenser.

In operation, the hot vapors are cooled to the condensation temperature and are condensed in the condenser and the resulting mixture of condensate and fixed gases is then separated. The fixed gases escaping may also include some smallamount of uncondensed very light vapors which may be recovered in` suitable recovery apparatus. The separated condensed distillate is discharged from the separator at atemperature somewhat above temperature, approaching that of the condensed distillate entering the cooler but below the temperature of condensation, and is then employed in the main condenser to cool and condense the hot vapors from the still. In general, all of the cooling water is first passed Vto the cooler and then to the lcondenser and the iiow ofcooling -wateris regulated to control the final temperature' of the condensed distillate as it escapes from the cooler. Additional cooling water may, however, be supplied either to the condenser or to the cooler, or to both.

Referring to Fig. 2, the vapors escaping from'the tower on the still enter the evaporative vcondenser through connection 6. In the evaporative condenser, the vapors enter headers 25 from which theyflow through horizontal tubes 26 and 27 and the return header 28 to headers 29 from which they are discharged from connection 30 to the condenser proper. The headers 25 28 and 29 and the horizontal tubes 26 and 27 are arranged within a receptacle 31 adapted to contain a relatively small body of Water submerging, or almost submer ing, the tubes 26 and 27. The tubes 26 and 2,7 may be provided with Vflanges or a series of annular rings or may consist of s ecial elements for increasing the amount o heat transferring surface. Water vapor liberated Within the receptacle 31 escapes upwardly through the stack 32, and openings 33 provided with dampers 34 are arranged in the upper part of the receptacle above the normal liquid level to permit a regulated draft of air to be drawn in over the surface of the water by the escape of steam through the stack to zation of the water. v

In the condenser proper, the partially cooled vaporsfrom the evaporative condenser, together with any condensate produced therein, flow downwardly through a series ofpipe coils'L in indirect heatv exchanging relation with the cooling wat-er in which they are immersed in a condenser box 9"; and from the condenser the condensed distillate and admixed gases are dischar ed into a separator 12, the lixed gases being discharged upwardly therefrom through theconnection 13a and the condensate downwardly through connection 14a. The separated condensate Hows through connection 14 to and through the cooler 15 and the cooled condensed distillate escapes` from the cooler through connection 16a. t

Cooling water is supplied through connection 17a and after passing through' connection 18a and the cooler' 15ll is circulated to the condenser box through connections 19.*

promote vaporiv and 1.0. Additional cooling water may be supplied to the condenser box through connections 20* and part of the water circulated Y through the cooler may be discharged through 'connection 21. The cooling water overflows is supplied to the evaporative condenser through the connection 36 at a'rate just sutiicient to maintain the level in the receptacle 31 as the Water is evaporated with the minimum of overfiow therefrom necessary for practical control. Suflicient cooling water is circulated through the cooler 15' to cool the condensed distillate to the desired `final temperature and sufiicient cooling water is supplied to the condenser 9a to condense the vapors from the still. VAdvantageously, all of the cooling water employed is circulated first through the cooler 15 and then through the condenser 9, and part of the water from the condenser 9 is employed inthe evaporative condenser. Additional cooling water may, however, be supplied to either operation to regulate the cooling or the condensation.

The hot vapors from the still first pass through the tubes 26 and 27 and cause evaporation of the relatively small volume of Water maintained in the receptacle 31 and are thereby partially cooled. Heavier constituents of the vapors-boiling above the boiling point of Water may also be condensed in whole or in part. The partially cooled vapors then enter the condenser proper where they are condensed, and after separation of the fixed gases, the condensed distillate is cooled to the desired final temperature in the cooler 15. A large part of the cooling of the condensate is thus carried on after the separation of fixed gases when it can be carried out more etticiently due to the absence of the fixed gases while the temperature of the vapors entering the condenser is also reduced, and by removing the major burden of cooling the condensed distillate from the condenser proper in this way a further improvement in the efficiency of the operation following is secured.

The vapors escaping from an oil still comprise a mixture of constituents of various boiling points, and condensation, or vaporization, of the different constituents takes place over a range of temperature rather than -at a single definite temperature. Different constituents alsovhave different specic heats as vapors and liquids and different heats of. vaporization. These factors. mayv var the saving of cooling Water which can be e ected in any given case.

It Will be apparent that the present invention provides an improved apparatus for condensing and cooling oil vapors and distillates in which the vapors from the still are first cooled and condensedby heat `exchange With cooling water and are then further cooled after separation of fixed Gases and in which cooling water isemployedifirst in the cooling operation and then in the cooling and condensing operation to which the vapors are first submitted. In cooling and condensing light fractions of low average boiling po1nt the temperature at which the distilled products are discharged from the c'ondenser dproper must be maintained at a cor,- respon ingly low point to insure effective condensation of all of the light constituents. With heavier fractions of higher average boiling oint, however, the distilled products. may be ischarged from the condenser proper at a correspondingly increased temperature y and a greater roportion of the cooling effected in the a er cooler.

It will also be apparent 'that the present invention provides an improved apparatus for condensing and cooling oil vapors and distillates in which the vapors from the still are first partly cooled, and in some cases partly condensed, by vaporizing a relatively small body of water, then further condensed by 'ving up additional heat to a relatively large bdy of Water as sensible heat, followed by cooling of the condensate after separation of the fixed gases. In the evaporative condenser, the temperature of the vapors may be reduced to a temperature somewhat above and approaching the temperature of water, and the amount of heat which can be extracted from the vapors by vaporizing water in the evaporative condenser varies with the character of the disl tillate as welll as with the temperature of the vapors escaping from the still, heavier vapors and hotter vapors giving up a greater, proportion of their heat therein. Where the condensation of the vapors and cooling of the' condensed distillate is carried out inthree stages in this wav, the load on the condenser proper is reduce both by reducing the temperature at which the vapors enter the condenser and by relievingthe condenser of the burden of cooling the condensate from the temperature of condensation to the desired final temperature.

What is claimed as new and desired to be secured by Letters Patent of the United States is 1. In combination in an apparatus for condensing and cooling vapors and distillates from oil stills, a condenser and a cooler, connections therebetween including a separator arranged to discharge liquid condensate 'to the cooler and to separate fixed gases, andmeans for supplying cooling water to the cooler and for su plying cooling water to the condenser from t e cooler.

2. In combination in an apparatus for condensing and cooling vapors and distillates from oil stills, an evaporative cooler, a condenser and connections for passing vapors and gases from the evaporative cooler therethrough, a separator communicating with the condenser, an after cooler and connections for passing liquid condensate from the separator through the cooler, and means for supplying water to the after cooler and for supf plying water to the condenser from theafter cooler. 3. In combination in an apparatus for condensing and cooling vapors and ,distillates from oil stills, an evaporative cooler, a condenser and connections for passing vapors Y and gases from the evaporative cooler therethrough, a separator communicating with the condenser, an after cooler and connections for passing liquid condensate from the separator through the cooler, and means for bringing water successively into heat exchanging relation with the after cooler and the condenser and for supplying the evaporative cooler with water from the condenser.

In testimony whereof I aix my siature.

LOLA R. B LL, Eec'utrz'a: of the LaatV Will and Testament of Jom E. Bell, Deceased.

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