US2030485A - Oil distillation - Google Patents

Description

J. s. WALLIS 2,030,485

OIL DISTILLATION Filed Deo. 5, 1930 Feb. l1, 1936..

2 Sheets-Sheet l I l u Z TVE TOR i WW1' MM Feb. 1l, 1936. J 5 WALLlS 2,030,485

OIL DISTILLATION Filed Deo. 5, 1930 2 Sheets-Sheet -2 fill 36 f 34 brface fonde/75er 36 36 gi/Sieg 46 f 46 Patented Feb. 11, 1936 UNITED STATES PATENT OFFICE to Foster Wheeler Corporation, New York,

N. Y., a corporation of New York Application December 3, 1930, Serial No'. 499,624

20 Claims.

My invention relates to oil rening apparatus.

I-Ieretofore it has been the practice in this art to make separate pieces of equipment for the vapor heat exchanger to which overhead vapors are conducted from a fractionating tower, the surface condenser to which the oil vapor next passes, the separator in the hot well of the vapor condenser, the barometric condenser for condensing the water vapor which leaves the tower with the oil vapor, and the vacuum run-down tank which receives the separated and liqueiied oil. This necessitates separate supporting steel structure, many connecting conduits, large space requirements and the accompanying expense necessitated by building separate items and the connection of these items into a system.

One of the objects of the present invention is to combine the heat exchanger, the surface condenser, the separator, the barometric condenser and the run-down tank all in a single unit, preferably a vertically disposed cylindrical drum. The combination of all these heretofore separate units in a single unit results in less supporting steel structure, less connecting conduits, less space requirements and is much cheaper. Furthermore, heat losses can be avoided and the danger of air leakage at high vacuum is reduced to a minimum.

Another object of my invention is to minimize the length of conduit between a fractionating tower and the apparatus or apparatuses for treating the oil vapor after its leaves the tower. By reducing the length of conduit I reduce the amount of expansion and contraction for which provision must be made. In the ordinary tower of the bubble tray type there are lateral portions of the bubble trays which are relatively ineffective. I eliminate these lateral portions or some of them as part of the bubble trays and provide one or more passages inside the tower laterally of the bubble trays for conducting overhead vapor downwardly within the tower to an intermediate point from which one or more conduits lead to the apparatus or apparatuses for subsequent .treatment. This also saves length of conduit and supporting steel work.

Further obj ects and advantages of my invention will be apparent from the following description considered in connection with the accompanying drawings, which are to be considered a part of this specication.

Fig. l is a view, partly in cross-section, of a preferred embodiment of my invention showing a fractionating tower in connection with my im.- proved combined unit;

Fig. 2 is a cross-sectional View taken on the line 2-2 of Fig. l;

Fig. 3 is a cross-sectional view of a portion of the fractionating tower shown in Fig. 1 but seen at right angles to the view shown in Fig. 1 and taken on the line 3-3 of Fig. 2;

Fig. 4 is a cross-sectional view of a preferred embodiment of the combined unit;

Fig. 5 is a cross-sectional view of the combined unit shown in Fig. 4 but seen at an angl-e of 90 degrees from the view in Fig. 4 and taken on the line 5-5 of Fig. 4;

Fig. 6 is a cross-sectional view taken on the line 6-6 of Fig. 4;

Fig. 'l is a cross-sectional view taken on the line 'I-l of Fig. 4; and

Fig. 8 is a cross-sectional View taken on the line 8-8 of Fig. 4.

Referring more particularly to Fig. l, reference character I0 designates a vacuum fractionating tower, the shell of which consists of a vertical cylindrical steel shell. An oil supply conduit II communicates with a lower portion of the tower, as shown. The tower below the point of communication of conduit II is of reduced cross-section as compared with that portion of the tower above and is provided with a series of bubble trays I2. Above conduit II there is located within the tower a series of baies I3 above which is a stripping section I4. Above stripping section I4 are a series of bubble trays I5, a stripping section I and another series of bubble trays Il. A by-pass conduit 9 having a valve 8 therein is provided around each of the stripping sections and, if Valve 8 is open, serves to convey liquid from the bubble tray above the stripping section, around the section and ontol the tray next below. All of these bubble trays I2, I5, and Il may be of similar type and comprise a tray portion I8 having central vapor passages I9 over which are bubble caps 2B having depending edges. Downflow conduits 2| serve to convey liquid from one bubble tray to the next. The stripping sections may be of any preferred design and comprise a member 2,2 secured to the interior of tower I0 and pro- 45 vided with a vertical flange 23 which forms a vapor passageway through the stripping section. The stripping section is the pocket dened by member 22, with flange 23 and the adjacent portion of the tower. Side streams may be with- 50 drawn from stripping sections I4 and IB through conduits 24 and 25, respectively, which convey the liquid collected at the stripping sections from the tower. A pump may be inserted in each of these conduits in order to force the liquid out of the 55 til tower against vacuum existing within the tower. A conduit 26 is supplied with superheated steam and in turn supplies this steam to branch conduits 21 and 28 which in turn distribute it within the stripping sections I4 and I6,respectively. The branch conduit 29 supplies superheated steam to the lower part of tower I0. A conduit 36 communicates with the bottom of the tower and conveys bottoms therefrom.

Some of the bubble trays, comprising the groups I5 and I1, are formed with straight edges to leave segment-shaped spaces between the trays and the interior of the tower shell. Member 22 defining stripping section I6 is formed in similar manner. Vertical plates 3I are secured within the tower with each vertical edge in contact with the cylindrical interior of the tower shell and with their inner surfaces in contact with and preferably secured to the straight edges of the bubble trays and of member 22. There are thus formed between the cylindrical shell of tower I and plate 3| segment-shaped, vertically extending passageways 32 which are open at the top and closed at the bottom by side extensions I a, of one of the bubble trays. Obviously the closing members for the bottoms of passageways 32 may be separate segment-shaped pieces and independent of the bubble trays.

While I have shown two passageways 32 it will be understood that there may be one or more of these passageways. Conduits 33 communicate with the bottom of passageways 32 and lead to opposite sides of the more central portion of a shell 34 which houses the combined heat exchanger, surface condenser, barometric condenser, and run-down tank. Conduits 33 open into a chamber 35 formed between vertical plates 36 which are placed within shell 34 vin a manner similar to that in which plates 3i, were placed Within the tower IU. The top of chamber 35 is closed by means of a plate 31. Within chamber 35 below th'e point of entrance of conduit 33 is located a bank of tubes 38 which constitute a heat exchanger.

The heat exchanger comprises an inlet header 39 and an outlet header 40 between which extend the tubes 38. These headers are secured to shell 34 in any suitable way, as by iiange members 4I. Below heat exchanger tubes 38 is a bank of surface condenser tubes 42 which extend between an inlet header 43 and an outlet header 44 in a manner similar to that described in connection with the heat exchanger.

Chamber 35, as defined by walls 36 extends some distance below the bank of condenser tubes 42 and there terminates in an open bottom, which communicates with the lower portion of shell 34, hereinafter referred to as vacuum run-down portion 45. The vertical plates 36 form a pair of segment-shaped passageways 46 between the plates and the interior of shell 34. These passageways are open at both the bottom and the top.

A conduit 41 supplies cooling water for the barometric condenser to a distributing device 48 which is located in the upper part of shell 34. Distributing device 48 comprises a cone-shaped member having a horizontal flange 49, the periphery of which contacts shell 34, and a vertical ange 50. Secured to flange 56 is a horizontal annular ring 5I provided with a series of apertures 5Ia. Below distributing device 48 within shell 34 is a battle and re-distributing device 52 which comprises a tray 53 formed with a series of apertures therethrough. Supported above tray 53 by means of members 54 is a cover plate 55, likewise provided with apertures. 'Ihe apertures in cover plate 55 and in tray 53 are not in alignment. Re-distributing device 52 extends the entire distance across the tower as viewed in Fig. 5 but as viewed in Fig. 4 there are passageways 56 left between the sides of the 1re-distributing device and the shell 34. Below re-distributing device 52 is a bafe and re-distributing device 51 through the central part of which' is a passageway 5B. Ete-distributing device 51 is similar to device 52 insofar as it comprises a tray 53 which has apertures 59a, formed therein and covered by cover plates 613 which are provided with apertures 66a out of alignment with the apertures in tray 53. Below re-distributing device 51 is a liquid receiver 6I which may be formed by hori- Zontal plate 31 in conjunction with an extended portion of vertical plates 36 and the shell 34. A conduit 62 communicates with liquid receiver 6I and extends downwardly a distance suiicient to hold a column of liquid corresponding to the vacuum maintained and preferably at least thirty-two feet and discharges into a well 63.

A conduit 64 communicates with the upper part of shell 34 and leads to a vacuum producing device, such as a steam jet vacuum pump 69. A conduit 65 leads from the vacuum run-down portion of shell 34 and communicates with the upper part of vacuum fractionating tower I3. A reux pump (not shown) is placed in this conduit in order to cause flow of liquid therethrough. A conduit 66 leads from the bottom of the vacuum run-down portion 45 to storage. A oat 61 operatively connected to a valve 68 serves to maintain a minimum quantity of liquid in the vacuum rundown portion of the shell. The float is arranged to close valve 68 when the level falls to a predetermined minimum.

The operation of the above described device is as follows:

Crude oil from storage or other source of supply is introduced into tubes 38 of the heat exchanger through inlet header 33 and passes therefrom through outlet header 43. In its passage through tubes 33 the oil is heated somewhat. The warm oil discharged from outlet header 4Q is conveyed to any suitable heater such as a tube still, where it is heated to the desired temperature and thence passed through conduit I I to the interior of vacuum fractionating tower I6, or it may rst pass into an atmospheric iractionating tower, the bottoms from which are then passed into vacuum fractionating tower I 0 through the conduit II. Any mode of heating the oil may be used. The oil may even be introduced directly into the tower and heated therein. There is also supplied to tower I0 superheated steam through conduit 26 and branch conduits 21, 28, and 29. This superheated steam reduces the partial pressure of the oil introduced into the tower and causes vaporization of a portion thereof. The oil vapor and superheated steam pass upwardly through the bubble trays I5 and I 1 and the oil vapor is acted upon and partially condensed by reflux liquid supplied through conduit 65. This liquid passes downwardly from one bubble tray to the next through down-flow conduits 2l and portions thereof are removed as side streams through conduits 25 and 24 from stripping sections I6 and I4, respectively, in a well known manner.

A portion of the oil remains in vapor form when it reaches the top of tower I0 and this oil vapor mixed with steam passes downwardly through passageways 32 formed between vertical plates 3| and the sides of the tower. The vaporous mixture passes from passageways 32 through conduits 33 to within chamber 35 formed within shell 34 by vertical plates 35. The vaporous mixture passes downwardly through chamber 35 and comes in contact with heat exchanger tubes 38. Here the mixture is cooled somewhat, at the same time heating the oil passing through tubes 38. The vaporous mixture of oil and steam continues downwardly through chamber 35 and comes in contact with surface condenser tubes 42 through which flows cooling water. A further reduction in the temperature of the mixture takes place at this point which results in the condensation of the oil vapor but not in the condensation of the steam. The liqueed oil drops out of the bottom of chamber 35 and is collected in the vacuum run-down portion i5 at the bottom of shell 34. The steam passes out of the bottom of chamber 35 and thence upwardly through passageways 46 formed between plates 35 and shell 34.

Cooling water is supplied to distributing device 48 through conduit 47 and passes' through the apertures formed in plate 5i and falls as a cylindrical curtain of water onto redistributing device 52. Here it strikes cover plate 55 and passes through the apertures formed therein and through the apertures formed in tray 53 which are so arranged as to produce a curtain of water on either side of the shell, which strikes re-distributing device 59. Re-distributing device 55 likewise causes the water to fall in a curtain on either side of the shell into receiver 5i, from which it passes through conduit 62 to well 53. The steam issuing from the upper ends of passageways 45 is caused to pass in a tortuous path through aperture 58 in baiiie 5l and around the re-distributing device 52 and hence passes through the curtains of water produced by these devices and is thereby condensed. Non-condensable gases, such as air, which are introduced into shell 34 are withdrawn therefrom through conduit 54 by a steam jet vacuum pump 35 or the like, which serves to maintain a vacuum within shell 34 and also within vacuum fractionating tower l5. Ine asmuch as the vertical distance between liquid receiver 6| and well 33 is suiiicient to give a great enough head of water to overcome the vacuum Within the shell, the water will ow from receiver 6l by gravity against the difference in pressure resulting from the vacuum maintained within the tower.

The oil collected in the vacuum run-down portion 45 of shell 34 passes therefrom through conduits 65 and 63, Tl'ie oil withdrawn through conduit 65 is introduced into the upper part of tower l0 and serves as reflux liquid while the oil withdrawn through conduit 55 isI passed to storage. Float 6'! maintains a minimum liquid level by regulating the rate of dischargev of oil through conduit 66.

Thus it will be seen that I have combined in a novel manner at least four units, which heretofore have been separate units, into a single struc* ture. Furthermore, I have greatly reduced the length of the conduit for conveying Vapor from the fractionating tower. If this vapor conduit communicated with the upper 'part of the tower shown in Fig. 1, it will be seen` that i't would be necessary to provide a conduit several times as long as are the vapor conduits 33 which I am able to use because of my invention.

While I have shown and described a preferred embodiment of my invention it is `to be understood that modifications thereof which are apparent to a person skilled in the art fall within its scope, which is to be limited only by the appended claims viewed in the light of the prior art.

What I claim is:

l. Apparatus for separately condensing and collecting oil vapors and steam from a mixture of the same, comprising a shell, means for introducing a mixture of oil vapors and steam into the shell, means for condensing the oil vapors from the mixture, means for collecting the oil condensate in the shell, a plurality of trays in the shell, means for introducing water onto one of the trays, means for distributing the water and causing it to flow in a curtain between at least two of the trays and through which` curtain the steam from said mixture is adapted to pass and be condensed thereby, means for collecting the water and steam condensate in the shell out of contact with the oil condensate and means for withdrawing the water and steam condensate from the shell.

2. Apparatus for separately condensing and collecting oil vapors and steam from a mixture of the same, comprising. a shell, means for introducing a mixture of oil vapors and steam into the shell, means for condensing the oil vapors from the mixture, means for collecting the oil condensate in the shell, a plurality of trays in the shell, means for introducing water onto the uppermost of said trays, means for distributing the water to cause it to ow in a curtain between said trays, said trays being arranged and disposed so as to cause the steam from said mixture to How through said curtains of water to thereby condense the steam, means below said trays for collecting the water and steam condensate and means for withdrawing the water and steam condensate from the shell.

3. Apparatus of the character described comprising a shell, means for maintaining a vacuum in the shell, a chamber in the shell, means for introducing a mixture of oil vapors and steam into the chamber, a heat exchanger in the chamber for cooling the vapors, a condenser in the chamber for condensing the oil vapors from the mixture, means for collecting the oil condensate in the shell, means for withdrawing the oil condensate from the shell, a plurality of trays in the shell, means for introducing water onto the uppermost of the trays, means associated with the trays for causing the water to flow in a curtain between said trays, a passageway between the chamber and the shell through which steam is adapted to flow from said chamber to said trays, said trays being arranged and disposed to cause the steam to flow in a circuitous path through the curtains of water to thereby condense the steam, a collecting tray below said trays for collecting the water and steam condensate and means for withdrawing the water and steam condensate from said tray.

4. Apparatus for separately condensing and collecting oil vapors and steam from a mixture oi the same, comprising a shell having an inlet for a mixture of oil vapors and steam, oil vapor condensing means in the shell below the inlet, means causing said mixture to flow downwardly into Contact with said condensing means to thereby condense the oil vapors from the mixture, means below the condensing means for collecting the condensate of the oil vapors in the shell, a steam condenser in the shell above the inlet, means causing the steam from said mixture to flow into contact with the steam condenser to condense the steam, and means in the shell below the steam condenser for collecting the steam condensate out of contact with the oil vapor condensate.

5. Apparatus for separately condensing and collecting oil vapors and steam from a mixture of the same, comprising a shell having an inlet for a mixture of oil vapors and steam, means for maintaining a vacuum in the shell, oil Vapor condensing means in the shell below the inlet, means causing said mixture to ilow downwardly into contact with said condensing, means to thereby condense the oil vapors from the mixture, means below the condensing means for collecting the condensate of the oil vapors in the shell, a steam condenser in the shell above the inlet, means causing the steam from said mixture to flow into contact with the steam condenser to condense the steam, and means in the shell below the steam condenser for collecting the steam condensate out of contact with the oil vapor condensate.

6. Apparatus for separately condensing and collecting oil vapors and steam from a mixture of the same, comprising a shell having an inlet for a mixture of oil vapors and steam, a heat exchanger in the shell below the inlet, means causing said mixture to flow downwardly into contact with the heat exchanger to thereby cool the mixture, oil vapor condensing means in the shell below the heat exchanger, means causing said cooled mixture to ilow into contact with said condensing means to thereby condense the oil vapors from the mixture, means below the heat exchanger for collecting the condensate of the oil vapors in the shell, a steam condenser in the shell above the inlet, means causing the steam from said mixture to flow into contact with the steam condenser to condense the steam, and means in the shell below the steam condenser for collecting the steam condensate out of contact with the oil vapor condensate.

7. Apparatus for separately condensing and collecting oil vapors and steam from a mixture of the same, comprising a shell having an inlet for a mixture of oil vapors and steam, oil vapor condensing means in the shell below said inlet, means causing said mixture to flow into Contact with said condensing means to thereby condense the oil vapors from the mixture, means below said condensing means for collecting the condensate of the oil vapors in the shell, a steam condenser in the shell above said inlet, means causing the steam from said mixture to flow into contact with the steam condenser without again coming into contact with the oil vapor condensing means to condense the steam, and means in the shell below the steam condenser for collecting the steam condensate out of contact with the oil vapor condensate.

8. An apparatus for condensing mixtures of hydrocarbon Vapor and the like comprising a vertical shell, a cooling unit within said shell, means for introducing hydrocarbon vapor above said cooling unit and means for directing the vapor downwardly over the unit to the lower portion of the shell and upwardly to the upper portion of the same independently of the downilowing vapor.

9. An apparatus for condensing hydrocarbon vapor and the like comprising a vertical shell, a cooling unit transversely disposed within said shell, means for introducing hydrocarbon vapor above said cooling unit, means for directing the Vapor downwardly over the unit to the lower portion of the shell, and for directing vapor fro-1n the said lower portion of the shell to the upper portion of the same independently of the downflowing vapor, the lower portion of the shell serving as a condensate receiver and condensing means disposed at the upper part of said shell.

l0. An apparatus for condensing vaporized hydrocarbons and the like, comprising a vertical shell, a plurality of heat exchangers removably.7 positioned in said shell, a baille partially surrounding said heat exchangers and forming a hood having its lower portion open and extending downwardly into the lower portion of said shell, said lower portion of the shell forming a receiver for the condensate and permitting it to collect in a pool, means for withdrawing the condensate from said pool, means for introducing vaporized hydrocarbons and the like into said hood forming baille, and means disposed above said heat exchangers adapted to condense the uncondensed portions of said vaporized hydro-- carbons.

11. A condenser as in claim l0, wherein said hood forming baille is spaced inwardly of said shell to form a passage for the uncondensed vapors leading to said condensing means.

l2. A condenser as in claim l0, in which a. condensate receiving means is disposed below said condensing means', an outlet for the condensate, and an outlet for the uncondensed portions of the vapors.

13. An apparatus for condensing hydrocarbon vapors and the like comprising in combination. a. shell, an inverted baille within the shell in spaced relation therewith, condenser tubes extending through said baille and means for introducing hydrocarbon vapors and the like into said baille.

14. An apparatus for condensing hydrocarbon vapor and the like comprising a vertical shell having a vapor inlet opening, and a condensate outlet opening in its bottom portion, a cooling unit disposed within said shell, means for directing the ilow of vapor from said inlet opening, over the cooling unit to the lower portion cf the shell and for changing the course of the vapor at the said lower portion of the shell and directing the same upwardly at the sides of the cooling unir, to the upper portion of said shell.

15. An apparatus for condensing hydrocarbon vapor and the like comprising a vertical shell having a vapor inlet opening, a cooling unit transversely disposed in the shell below said inlet, a baille structure disposed so as to enclose said unit within said shell and adapted to direct the flow of vapor over said unit, said shell having a condensate outlet opening in its lower portion below said cooling unit, and said baille structure providing a space between the cooling unit and the shell to permit the upward passage or vapor from the said lower portion of the shell to the upper portion of the same.

16. An apparatus for condensing hydrocarbon vapor and the like comprising a vertical shell having a Vapor inlet opening, a. cooling unit transversely disposed in the shell below said inlet, a baffle disposed above and at the sides of said unit within said shell and adapted to direct the ilow of vapor over said unit, said shell having an outlet opening in its lower portion below said cooling unit, said baille providing a space at the side of said shell to permit the upward passage of vapor from the said lower pcrtion of the shell to the upper portion of the same. and vapor condensing means disposed at the upper end of said shell.

17. An apparatus for condensing hydrocarbon vapor and the like comprising a vertical, substantially cylindrical shell having a vapor inlet opening, a cooling unit transversely disposed in the shell below said inlet, the lower portion of said shell embodying a condensate receiving zone and having an outlet c-pening for liquid condensate, baille plates disposed above and at the sides of the cooling unit adapted to direct the flow of vapor from the said inlet port over said cooling unit, said baffles providing segmental spaces at the sides of said unit permitting the upward passage of vapor from the lower portion of the shell tc the upper part of the same.

18. An apparatus for condensing hydrocarbon vapor and the like comprising a vertical, substantially cylindrical shell, a cooling unit transversely disposed within the shell, baffling means above and at the sides of said cooling unit, means for introducing hydrocarbon vapor above the cooling unit within said baiiles, said baiiles at the sides of said cooling unit providing passageways at the sides of the said cylindrical shell adapted to permit the passage of vapor from the lower portion of the shell to the upper portion of the same, and condensing means disposed above the said upper baille.

19. An apparatus for condensing hydrocarbon vapor and the like comprising a vertical, substantially cylindrical shell having a vapor inlet opening, a cooling unit transversely disposed in the shell below said opening, the lower portion of said shell embodying a condensate receiving zone and having an outlet opening for liquid condensate, baiiie plates disposed above and at the sides of the cooling unit adapted to direct the ow oI Vapor from the said inlet port over said cooling unit, said bales providing segmental spaces at the sides of said unit, permitting the upward passage of residuary uncondensed vapor from the lower portion of the shell to the upper part of the same, means in the upper part of said shell above the said inlet opening for condensing the said residuary Vapor, and means for separately withdrawing the condensate from the receiving Zone of the shell, the condensate of the residuary vapor, and the non-condensed vapor.

20. An apparatus for condensing hydrocarbon vapor and the like comprising a vertical, substantially cylindrical shell, a cooling unit transversely disposed within the shell, baflling means above and at the sides of said cooling unit, means for introducing hydrocarbon vapor above the cooling unit within said baffles, said baies at the sides of said cooling unit providing passageways at the sides of the cylindrical shell, adapted to permit the upward passage of vapor from the lower portion of the shell tothe upper portion of the same.

JOHN SAMUEL WALLIS.

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