US1530325A

US1530325A - Oil dephlegmator

Info

Publication number: US1530325A
Application number: US581050A
Authority: US
Inventors: Price Joseph
Original assignee: Griscom Russell Co
Current assignee: Griscom Russell Co
Priority date: 1922-08-11
Filing date: 1922-08-11
Publication date: 1925-03-17
Anticipated expiration: 1942-03-17

Description

March 17, 1925. 1,530,325

- J. PRICE OIL DEPHLEGMATOR Filed Aug. 11. 1922 ATTOkNEY g the heavier fractions in the Patented Mar. 17, 1925 UNITED STATES 1,530,325 PATENT OFFICE.

JOSEPH PRICE, or nEwYonx, N. Y., AssIqNon TO THE eR Iscoir-nossELI. oonrAnY,

or NEW YORK, 11. Y., A conrona'rron or DELAWARE.

OIL DEPHLEGMATOB.

Application filed August 11, 1922. Serial No. 581,050.

To all whom it may con/cam:

Be it known that I, J osErH PRICE, a citizen of the United States, residing at New York city, in the county of Bronx, State of New York, have invented certain new and useful'lmprovements in Oil Dephleg-v mators; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make ang use the same.

The present inventid relates to apparatus for use in oil refining processes, and has to do particularly with a dephlegmator or similar apparatus for cgkpdensing out I t Va rs issuingv from the evaporating cha hen or still and passing the lighter fractionswhn in the form of vapor.

Crude petroleum or similar substance consists of a number of different 'constitutents, each of which has a distinct vaporization temperature. The product distilled off from a body of crude petroleum at a given temperature does not consist solely of the particular constituent whose boiling point .corresponds to this temperature, but contains appreciable quantities of other constituents or fractions of different vaporization temperatures. To increase the purity of the distilled product re-distillation of the previously distilled portions has been resorted to. This method is, of course, open to the objection that much additional expense is involved in the time required to accomplish the re-distillation processes and in the provision of additional heat for effecting the second evaporation. It has also been proposed to effect re-distillation of the product in the same apparatus thatreceives the hot vapors issuing from the. still in which the original evaporation is carried out. For accomplishing this purpose the hot vapors from the still generally are passed through a condenser in which the heavier fractions are condensed and the greater part of the lighter fractions remains in vaporous form and may be passed out of the apparatus. The condensate issuing from the condenser is then subjected to the action of a heating element provided in the same apparatus and maintained at such temperature as to permit only certain of the heavy fractions to pass, at the same time re-evaporating a ortion of the lighter fractions and passing t e vapor thus formed back into the pgincipal vapor passage.

It has also en proposed to effect reevaporation of the lighter fractions which have been condensed along with the heavier tion, the dephlegmator is commonly .pro-

vided with a chamber for receiving the hot vapors, the chamber being either an open space or having a bafiie or tubes projecting into 1t. After circulating about in this chamber the hot vapors are passed into a condenser whose cooling medium is cold water, oil, or other medium at relatively low temperature. A ortion of the lighter fractions will pass t rough the condenser uncondensed but the heavier fractions, together with a portion of the lighter fractions, will be condensed and will drain back into the lower chamber. In this chamber, however, the condensate comes in contact with the incoming hot vapors, and the result is that the lighter fractions are again vaporized and will pass up into the condensing element. The'intent of such an apparatus is to obtain a flow of the heavier fractions out of the apparatus in the form of condensate, while the lighter fractions are passed on through the condenser in the form tion that the outflowing stream of lighter fractions in the form of va or invariably carries a part of the heavier ractions along through the condenser before condensation occurs.

It is accordingly an object of this invention to provide an oil refining apparatus or dephlegmator of the above. type in which only the heavier fractions of the vapor are condensed, thus avoiding the necessity of re-evaporating lighter fractions of the vapor with the consequent danger of contaminating the distilled product with constituents of different volatility.

It is a further object of the invention toprovide an apparatus of the above type in. which the condensed heavier fractions and the vapors comprising .the lighter fractions, after issuing from the condenser, are separated in a thorough and efficient manner, whatever particles of the condensate have become entrained with the vapor bemg separated out.

It is also an object to provide an apparatus of this character in which the condensation temperature may be regulated so that constituents of greater or lesser volatility may be included in the condensate, yet in which during a perlod of operation the condensation temperature is automatically maintained at a fixed value sov that distilled products of uniform purity may be obtained.

It is a further object to provide an apparatus of this type in which a heat transfer of maximum efficiency is obtained for effecting condensation of the heavier fractions of the vapors.

It is a still further object to provldean apparatus of this type of improved des gn such that its construction will be effective and inexpensive, provision being made for convenient disassembling ofthe parts of the apparatus and for removing scale or other impurities which may accumulate on the heat transferring surfaces.

In carrying out the invention the hot vapors from the still are admitted to the dephlegmator and are brought 1nto heat transferring relation with a cooling medium. The temperature ofthe cooling medium is regulated as desired to correspond to the vaporizing temperature of the least volatile fraction which it is desired to include in the vaporous distillate. When the temperature of the cooling fluid is thus regulated to a desired value it is maintained at this tem perature by automatic means provided for this purpose. The products from the still are passedin intimate heat transferring relation with the cooling fluid and are maintained in such relation for a length of time suflicient to insure complete condensation. For the purpose of increasing the heat transfer rate between the incoming vapors and the cooling liquid, the liquid is preferably maintained in a state of constant ebullition or agitation so that a continuous circulation and consequent distribution of heat will be maintained. It may be seen, then, that only those fractions will be condensed whose condensation temperatures are above the temperature of the cooling fluid while all of the lighter fractions of the product will remain in vaporous form and may be passed on in this state to be condensed and stored. The mixed vapors and condensate issuing from the condenser are preferably passed into a separator, the vapor being there freed of entrained particles of condensate and subsequently passed out of the apparatus.

trating another embodiment of my invention; and t Fig. 4 is a detailed sectional view taken on line 4-4 of Figure 3 showing the separator head.

Referring to the drawings. 1 indicates the shell or housing for the condensing element of the dephlegmator, and 2 the casing which houses the separator for dividing the liquid portion of the distillate from thevaporous portion. At the upper end of the apparatus is a head or chamber 3 containing an inlet opening 4 through which'the crude oil vapor issuing from the still is admitted to the dephlegmator. The chamber 3 is in communication with the upper ends of the heat transferring tubes 5, which tubes extend longitudinally of the 'apparatus between the supporting tube sheets 6 at each end of the housing 1. The tubes 5 may be straight tubes extending between the plates 6, but I preferably employ tubes having the middle portion of their length bent out of a straight line connecting their ends, as shown in the drawings. This construction facilitates the removal of scale or other impurities which may collect on the surface of the tubes inasmuch as the tube surface may be flexed bysubjecting it to a sudden change in temperature as, for instance, by admitting cold water to the tubes when they are in a heated condition. Such a sudden change in temperature causes the tubes to contract and the bowed portion of the tube assumes a conformation approaching a straight line. The change in conformation of the tubes and their consequent scale cracking power is increased when the middle portion of a tube is normally deformed only a slight distance out of a straight line connecting its ends, since with this condition the maximum amount of lateral movement occurs with a. given elongation or contraction of the tube. The lower ends of the tubes 5 are in communication with the separator 2. The vapor thus enters the apparatus, traverses the length of the tubes 5, passes into the separating chamber 2 partly as condensate and partly as uncondensed vapor, and issues from the separator chamber through the condensate outlet 7 and vapor outlet 8 respectively. The apparatus is usually embodied in a vertical unit as shown.

The cooling liquid for condensing the oil paratus.

.vapors is contained within the housing 1 and occupies the space surrounding the heat transferring tubes 5. Oil or other liquid may be employed, but I preferably use water as the cooling medium inasmuch as I am able to obtain a 'better heat transferring eliic-iency. The water inlet 9 is preferably located near the bottom of the shell 1 and through it water is supplied in proper quantity from any desired source. For regulating the quantity of the inflowing water a float 10 is provided to actuate the inlet valve 11, the float being raised with rising water level in the shell 1 to close the valve 11 and exerting the opposite action when the water level in the shell 1 falls.

For maintaining the proper temperature within the shell 1 I provide a back pressure valve 12 in the steam line 13 leading from the vapor space at the upper-end of the ap- The heat transferred to the cooling water by the vapors passing through the tubes 5 serves to keep the entire body of water within the shell in a state of ebullition. By means of the back pressure valve any desired pressure may be maintained in the shell, and steam will be permitted to escape through the line 13 only when an excess pressure is developed in the shell. The steam will. of course, be saturated and conse-quently there is a definite temperature corresponding to any desired pressure for which the valve 12 may be set to regulate. In this manner the temperature of the cooling liquid is automatically maintained at a certain value depending upon the regulation of the valve 12. The steam passing out through the line 13 is preferably conveyed into heat exchanging relation with the feed water supply to the shell and the available heat of this excess steam thus utilized. This may be conveniently accomplished by conveying the steam into a condenser or similar heat exchanger 14 and the feed water passed through the same apparatus and heated to within a few degrees of the temperature in the-shell. By heating the feed water to a uniform temperature approximately that of the temperature in the shell, the temperature along the entire length of the heat transferring tubes 5 is substantially constant and at the proper value for effecting the condensation of only those fractions which it is desired to condense. Condensation of the lighter fractions which should be passed through in vaporous form is avoided.- The excess steam may, of course, be utilized in any other manner as desired.

The water within the shell 1 is in a state of constant ebullition. Due to the boiling the entire volume of the water is agitated, and this agitation serves to effect a circulation and maintain a uniform temperature throughout the body of the liquid. As a result all of the liquid is brought repeatedly into intimate contact with the heat transferring tubes 5 and a high rate of heat transfer results. The apparatus is designed so that the vapors in passing through the condensing portion of the apparatus have ample opportunity to come into heat transferring relation with the cooling water in the shell. It is thus clear that all of the constituents of the crude oil vapor whose vaporization temperatures are higher than the temperature of the cooling liquid will be condensed. while those constituents whose vaporization temperatures are lower than the cooling liquid are forced to pass through the tubes 5 uncondensed. This is in contrastto the use of a relatively cold cooling liquid as in the ordinary type of condenser, where in order to avoid complete condensation of the vapors the volume of distillate must be hurried through the condenser so quickly that complete condensation cannot 1 occur. In this old type of condenser it is evident that the condensation of the heavy constituents will be imperfect. That is, some of the lighter fractions are bound to be condensed along with the heavier frac tions in order to insure complete condensa-.

tion of the heavier fractions. In the present embodiment of my invention it is possible to effect complete condensation of a predetermined number of the heavier fractions, while the lighter fractions remain completely uncondensed.

The heavier fractions issuing from the tubes 5 as condensate and the lighter frac tions occurring as a vapor enter immediately into the'separator 2, which comprises a bat- He 15 serving to impart a whirling motion to the fluid. Due to the centrifugal action arising from this whirling motion whatever particles of condensate are entrained in the vapor will be thrown to the outer wall of the shell, while the vapor will enter the opening 16 provided in the central core tube 17 of the separator and will find its way out of the apparatus through the outlet 8. The condensate will collect in the bottom of the separator housing 2, its level being determined by the outlet 7 provided at any de-' sired height in the separator casing. The function of the separator is independent from that of the condensing portion of the dephlegm-ator and serves not to condense out any of the fractions occurring in the vapor but merely to separate out whatever condensate has already formed and thus do liver a purified product both through the condensate outlet and the vapor outlet.

In Fig. 3 I have illustrated a modified form of apparatus in which the flow of vapor is up instead of down, which condition may be desirable in certain instances. The structure is in general similar to they embodiment above described. The crude oil vapor enters at the inlet opening I near the bottom of the apparatus and passes up through the length of the condensing tubes 5 into the separator 2, from whence the vaporous portion of the fluid 1s discharged through the outlet open ng 8. A battle plate 22 is preferably provided ad acent the vapor inlet 4 for the purpose of protecting the ball float 23 from down falling oil condensate. The condensate forming during the passage of the fluid along the tubes'5 drains back down the length of the tubes into the chamber 24 at the bottom of the apparatus which may be a separate compartment as shown. The condensate accumulates in the bottom of this compartment and is discharged through the outlet opening 7. If desired, a float 23 controlling the valve 18 in the condensate discharge line may be provided. The construction of the separator 2 is slightly different from that above described, inasmuch as the main body of the condensate does not enter the separator the separating operation need not be carried out to as great an extent. The vapor containing whatever particles of the condensate have been entrained in it issues from the upper ends of the tubes 5 and enters the central passage 19 of the separator. This passage 19 is provided with a lateral opening, 20, which opening is bisected by a flange or wall 21 provided on the shell 2 of the separator and serving to divide the outflowing fluid into two portions, each effecting a rotation half way around the separator body.

centrifugal force of rotation causes the entrained particles of condensed liquid to be thrown against the outer walls of the separator head while the vapor continues in its rotation and is discharged through the opening 8, which opening assumes the form of a tubular passage extending an appreciable distance into the interior of the separator head 2 in order to prevent discharge of any condensate which has been separated out. The condensate drains down from the separator head through the line 25 and mingles with the principal body of condensate in the lower chamber 24. The embodiment of Fig. 3 may, of course, be equipped with means For preheating the cooling fluid admitted to the shell 1, for regulating the inflow of the cooling fluid by means of a float valve, and the like. The back pressure valve 12 serves to maintain the desired temperature within the shell 1.

\Vhile the intent of the present invention is primarily to maintain the temperature of the condensing water in the shell 1 at such value as to condense out only certain desired fractions, the temperature of this water may be maintained somewhat lower than the theoretically proper value, if desired, and means may be provided for a greater or lesser reevaporation of the con- The densate issuing through heat transferring tubes 5. For this purpose the chamber 24 would preferably be provided with one or more baflles to receive the condensate issuing from the lower ends of the tubes 5 and at the same time directthe incoming hot vapors from the still into contact with the condensate. In this manner a portion of the lighter fractions of the condensate would be reevaporated.

While I have illustrated and described a preferred embodiment of my invention, it is to be understood that the invention is not limited to the structural details shown andits embodiment may be varied within the full scope of the appended claims.

I claim:

1. An apparatus of the class described comprising a portion for receiving hot vapors, said vapors having constituents of different boiling temperatures, means for providing a cooling medium in heat transferring relation with said'vapors, means for regulating the temperature of said cooling medium to effect condensation of a definite number of said constituents and means for introducing additional cooling medium to replenish that lost through evaporation without substantially disturbing the temperature of the principal body of the cooling medium.

2. Apparatus of the class described comprising a portion for receiving hot vapors, said vapors having constituents of difierent vaporizing temperatures, a chamber in heat exchanging relation with said vapors for containing a cooling medium, means for maintaining the temperature of the cooling medium intermediate the maximum and minimum vaporizing temperatures of said constituents, whereby the heavier constituents may be completely condensed and the lighter constituents remain totally uncondensed, means for maintaining a circula- 0 tion of said cooling medium by withdrawing a portion of said medium and adding additional cooling liquid to compensate therefor and means for controlling the temperature of the coolingliquid admitted 116 to said chamber to substantially the temperature maintained in said chamber.

3. Apparatus of the class described. comprising a passage for receiving hot vapors, a chamber in heat exchanging relation therewith for containing cooling liquid, the heat given up by said incoming vapors effecting ebullition of the cooling liquid, means for maintaining said cooling liquid at a predetermined temperature, means for discharging the vapor thus formed, means for condensing said vapors and means for supplying additional cooling liquid to said chamber containing heat derived from said discharged vapors.

4. Apparatus of the class described comprising a passage for receiving hot vapors, a chamber in heat exchanging relation therewith for containing cooling liquid, the heat given up by said incoming vapors effecting ebullition of the cooling liquid, means for discharging the vapor thus formed at a predetermined pressure Whereby the liquid in said chamber is maintained at a substantially constant temperature, means for replenishing the cooling liquid in said chamber by admitting additional cooling liquid thereto and means for transferring heat from said discharged vapors to said additional liquid to thereby control the temperature of said added liquid to substantially the temperature maintained in said chamber.

5. Apparatus of the class described comprising a chamber for containing cooling liquid, a passage for hot vapors having a large heat transferring surface distributed throughout the volume of the liquid in said chamber, the heat given up by said incoming vapors effecting ebullition of the cooling liquid, means for discharging the vapor thus formed at a predetermined pressure whereby the liquid in said chamber is maintained at a substantially constant temperature, means for replenishing the cooling liquid in said chamber by admitting additional cooling liquid thereto and means for transferring heat from said discharged vapors to said added liquid to thereby control the temperature of the liquid entering said chamber to approximately the temperature maintained in the chamber.

6. Apparatus of the class described comprising a passage for receiving hot vapors, a chamber in heat exchanging relation with said passage for containing cooling water, the heat given up by said incoming vapors efi'ecting ebullition of the cooling Water, and means for maintaining in said chamber a temperature intermediate the maximum and minimum vaporization temperatures of the constituents in the incom-- ing oil vapors, said means comprising a back pressure valve for automatically maintaining a predetermined pressure in the chamber, whereby the temperature in the chamber is the vaporization temperature corresponding to the pressure maintained by said valve, and means for conveying steam discharged from the chamber into heat exchanging relation with the cooling water admitted to the chamber thereby preheating said cooling water.

7. Apparatus of the class described comprising a passage for receiving hot vapors, a chamber in heat exchanging relation 'with said passage for containing cooling water, the heat given up by said incoming vapors effecting ebullition of the cooling water, and means for maintaining in said chamber a temperature intermediate the maximum and minimum vaporization temperatures of the constituents in the incoming oil vapors, said means comprising a back pressure valve in said discharge line for automatically maintaining the predetermined pressure in the chamber, whereby the temperature in the chamber is the vaporization temperature corresponding to the pressure maintained by said valve, means for maintaining the liquid in the chamber at a substantially constant level, means for adding cooling liquid to said chamber to con'ipensate for the steam discharged therefrom and means for heating said added liquid before admission to the chamber to a temperature approximately equal to that maintained in said chamber.

8, Apparatus of the class described comprising a passage for receiving hot vapors, a chamber in heat exchanging relation with said passage for containing cooling water, the heat given up by said incoming vapors efi'ecting ebullition of the cooling water, and means for maintaining in said chamber a temperature intermediate the maximum and .minimum temperatures of the constituents in the incoming oil vapors, said means comprising a line for discharging steam resulting from the ebullition 1n the chamber, a back pressure valve in said discharge line for automatically maintaining a predetermined pressure in the chamber, whereby the temperature in the chamber is the vaporization temperature corresponding to the pressure maintained by said valve, and means for preheating the cooling water before :uhnission lo the apparatus to approximately the temperature of the Water in the chamber.

In testimony whereof I affix my signa ture.

JOSEPH PRICE.

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