US2544885A - Vertical tube evaporator - Google Patents

Description

M r h 1 5 H. E. JACOBY ET AL 2,544,885

VERTICAL TUBE EVAPORATOR Filed Feb. 27, 1946 2 Sheets-Sheet 1 INVENTOR ATTOR EYS March 13, 1951 H. E. JACOBY ETAL VERTICAL TUBE EVAPQRATOR 2 Sheets-Sheet 2 Filed Feb. 27, 1946 IL wm UN? INVENTOR Harold E. Jacoby' BY CheriesPzVz'Zen Qa ATT Patented Mar. 13, 1951 VERTICAL TUBE EVAPORATOR Harold E. J acoby, Brooklyn, and Charles P. Nilan, Point Lookout, N. Y., assignors to General American Transportation Corporation, Chicago, 111., a corporation of New York Application February 27, 1946, Serial No. 650,468

6 Claims. (Cl. 159-27) This invention relates to evaporators and more particularly to a novel unitary construction of evaporator body adapted to be incorporated in a multiple effect evaporating system.

A multiple effect evaporator commonly comprises two or more evaporator bodies each of which includes a heating element and a vapor separator chamber, the evaporator bodies being so interconnected that the vapors from one body or effect are fed to the heating element of the next effect. In evaporators of the type with which the present invention is concerned the liquor (i. e., any liquid which is to be evaporated) is heated within a heating element, usually of tubular construction, by transfer of heat from vapors outside the tubes. Movement of the liquor through the tubes is achieved either by maintenance of a suitable hydrostatic head of the liquor or by pumping the liquor through the tubes or by utilizing the thermosiphon action induced by heat transfer from the outside of the tubes to the liquor within the tubes or by a combination of two or more of these methods.

In addition to the evaporator body itself, it is the usual practice to provide a device known as an entrainment separator for removing any entrained liquor from the vapors formed in the evaporator. This is commonly done in a separator chamber which drains the separated liquor back to the evaporator. It is also known to provide one or more flash chambers through which steam condensate or superheated liquor are passed. In these flash chambers the hot liquor or condensate is exposed to a lower pressure at which its own heat serves to produce spontaneous vaporization or flashing of a part of the liquid and thereby to avoid possible waste of such heat. Each one of the evaporating units at different pressures is called an effect. Since the steam or vapor pressure in successive effects decreases,

- condensate from any effect except the last effect contains heat that may be converted into steam and used as a heating medium in a successive effect. By causing the steam condensate from one effect to flow into a flash chamber maintained at the lower pressure of another effect, a portion of the condensate vaporizes and may be used as a heating medium in the latter effect. In somewhat similar fashion, in cases where the liquor fed to the evaporator is superheated with respect to the conditions existing in the effect into which the liquor is to be introduced, the liquor may be passed through a liquor flash chamber to permit flash evaporation of a portion thereof.

It is an object of the present invention to provide an improved evaporator body construction wherein the evaporator body contains not only the usual heating element and vapor separator chamber but may also contain an entrainment separator or a condensate flash chamber or a liquor flash chamber or any two or all three of these additional elements. By incorporating the entrainment separator and flash chambers in the evaporator body in accordance with the present invention a completely self-contained and selfsupporting unit may be achieved. Such a selfcontained and self-supporting unit eliminates the necessity of expensive structural steel supports such as have been previously used for sup- "porting the different elements of an evaporator.

The work involved in installing an evaporator system and the cost of installation are thus reduced materially, since apart from accessories, such as pipes, pumps and the like only a single unit of the equipment need be handled for each effect'that is to be installed. Further the compactness of an evaporator incorporating the present construction reduces the space require-' that these arenot intended to be exhaustive or limiting of the invention. On the contrary, we are giving these as illustrations and are giving herewith explanations in order fully to acquaint others skilled in the artwith our invention and the principles thereof and a suitable manner of its application in practical use, so that others skilled in the art may be enabled to modify the invention and to adapt it and apply it in numerous forms each as may be best suited to the requirement of a particular use.

The many objects and advantages of the present construction may best be appreciated by reference to the accompanying drawings which illustrate an evaporator incorporating a preferred embodiment of the invention and wherein:

Figure 1 is a vertical section through the evaporator showing the arrangement of theprincipal elements within the evaporator body; and

Figure 2 is a diagrammatic illustration of the manner in which evaporator bodies incorporating the present invention may be interconnected in a multiple effect evaporating system.

Referring to the drawings, and more particular ly to Figure 1, the numeral generally designates an evaporator body comprising a cylindrical outer shell or casing ii that encloses a vapor separator chamber 2, a heating element comprising the tube bundle [4, an entrainment separator chamber [6, a liquor flash chamber I8 and a condensate flash chamber 20. (Relatively few tubes are shown in the tube bundle on. the drawing to avoid confusion of lines; but any required numbermay be used in accord with accepted engineering principles.) This tube bundle 14 comprises a plurality of tubes that are mounted in the usual manner in an upper tube sheet 22 and a lower tube sheet 24. The lower tube sheet 24 is mounted between a flanged condensate receiving section 26 of the evaporator body it and a flanged ring 28. Closure of the lower end of easing H is provided by a flanged cap section 38 connected to the flanged ring 28 in such manner that it may be easily removed to provide ready access to the tubes of the tube bundle Hi. the upper end of casing H a cap 31 is provided that may be removed to permit access to the vapor separator chamber l2 and upper tube sheet 22.

The upper tube sheet 22 is supported by an annular ring 32 fixed to the casing II. An expansion joint 34 is provided between the tube sheet 22 and supporting ring 32 to permit necessary expansion of the tubes of the tube bundle i l. The tube sheet 22, expansion joint 36 and ring 32 effectively comprise a wall of the vapor separator chamber I2.

Surrounding the upper and central portions of the tube bundle Hi there is a cylindrical partition 38 that is supported from the vertical wall of casing i I by an upper annular ring 38 and lower annular ring 48. The cylindrical partition 38 and annular ring 33 cooperate with the vertical wall of the casing H to define the annular opentopped entrainment separator chamber l5 into which the vapors from a previous efiect may be introduced tangentially through a pipe 42. The construction is such that the vapors entering through the pipe G2 are whirled around in the chamber I6 and non-gaseous constituents contained in the vapors are removed. The separated liquor is removed from the chamber it through a connection 44 and the vapors that have been freed from entrained liquor fiow over the top of the cylindrical partition 36 and thence downwardly in contact with the tubes of tube bundle As previously pointed out, the liquor to be evaporated may be superheated and it is desirable that a flash chamber be provided for removal of this superheat before subsequent utilization. The annular rings 38 and All, the lower portion of cylindrical partition .35 and the vertical wall of casing l define an enclosed annular liquor flash chamber [8 that may be used for this purpose. Liquor may enter the chamber 18 through a connection 46 and leave the chamber through a connection 48. Within the chamber 18 the pressure is maintained at such a value that a suificient portion of the entering liquor flashes into steam to de-superheat the liquor. The evolved vapor may be withdrawn through a connection 50 near the top of the chamber l8.

Liquor leaving the chamber 18 through connection 48 may be conducted by a pipe (not shown in Figure 1) to a connection 52 in the flanged ring section 28 of the evaporator body. The liquor thus introduced passes upwardly through the tubes of tube bundle M where it is heated by condensation outside the tubes of either steam or vapors from a preceding effect. As the liquor passes through the tubes, and evaporation of the liquor occurs, the velocity of the mixture 01 liquor and vapor increases, and the vaporliquor mixture leaving the upper end of the tubes of tube bundle l4 impinges upon a curved bailie plate 54 that is mounted in the path of the vaporliquor mixture to deflect the mixture downwardly. Separation of the vapor from the liquor in this mixture occurs within the vapor separator chamber 12 and the vapors leave the evaporator body through an outlet connection 56 near the top of the vapor separator chamber. The liquor thus separated may be withdrawn from the vapor separator chamber through a connection 53.

To utilize the superheat that may be present in the condensate from a previous effect a condensate flash chamber 20 is provided near the bottom of body I9. Surrounding the lower portion of tube bundle Hi there is a cylindrical partition 63 that cooperates with the casing wall H to define the open-topped annular condensate flash chamber 2e. Condensate from a previous efiect may enter the chamber 28 through a connection 52 and vapors flashing from the condensate pass over the top of cylindrical partition 55 into contact with the tube bundle is. The partition 58 forms a baille that effectively prevents the entering condensate from impinging directly on the tubes of tube bundle lil. De-superheated condensate flows through a'hole 6 3 in the partition 68 thence downward into the condensate receiving section 25 and out of the evaporator body through condensate outlet connection 66.

The vapors entering the evaporator body through the inlet connection 42 normally contain a small proportion of non-condensible vapor that tends to collect in the central and lower portions of the tube bundle is and means are provided for removing this non-condensible vapor. Centrally located in the tube bundle Hi there is a tube 68 that extends from the upper tube sheet 22 down through the center of tube bundle it, through the lower tube sheet 24 and then out through the wall of flanged ring 28. Near its lower end tube 68 is provided with a plurality of holes '58 through which non-condensible vapor that collects in the lower central portion of the tube bundle may pass to the interior of tube 58 and be withdrawn from the evaporator body, e. g., by an ejector or pump or by venting, depending upon the pressure. It is apparent that only the lower portion of tube 68 is effective in withdrawing non-condensible vapors from the evaporator body but it is desirable that the tube 58 extend to the upper tube sheet 22 so that the symmetry of the tube bundle may be preserved and channelling of the steam or'vapors avoided. If the tube 63 did not extend upwardly to the upper tube sheet, the resulting opening in the center 01 the tube bundle would provide a bypass through which steam .or hot vapors might flow without coming in contact with the heating surfaces of the tube bundle. This feature of the present evaporator is described more fully in copending application Serial No. 712,810 filed on November 29, 1946.

The evaporator body ill may be supported in any suitable manner. In the present embodiment the casing H and its associated structure is supported on a cylindrical skirt 12 that is fixed to the casing in any suitable manner, such as by welding, and extends from the bottom of the casing to the iioor or other structure on which the evaporator body is mounted. An opening 74 is provided in the skirt I2 to permit access to the lower portion of the evaporator body. It is apparent that other supporting means such as structural steel legs in the form of T-beams or I-beams may be used in place of the skirt 12.

The evaporator of the present invention is particularly adapted for use in multiple effect evaporating systems and the manner in which a number of evaporator bodies incorporating the present invention can be interconnected in a multiple effect system is illustrated diagrammatically in Figure 2 of the drawings. Referring to Figure 2, the numerals I68, I82 and I04 designate the several evaporator eifects having bodies Illa and IE1) generally similar to the evaporator body Ill shown in Figure l. Superheated liquor to be evaporated is fed to the liquor fiash chamber Ida of evaporator body Iuc of the final effect it through a pipe I66, and the superheat removed by partial vaporization of the liquor. From the liquor flash chamber of body Idc the liquor flows through pipe I98 to the bottom of the evaporator body Ito, enters the evaporator body through the connection 52a and then flows up through the tube bundle of this evaporator body to the vapor separator chamber I20 wherein the liquor and associated vapor are separated. The liquor leaves the evaporator body Iiic through pipe H9 and is transferred by means or" transfer pump H2 and pipe H4 to the bottom of evaporator body Ifib of the effect I02.

Since the liquor at this stage contains no superheat it is unnecessary that the evaporator body Iiib be provided with a liquor flash chamber. The entering liquor passes up through the tube bundle in the evaporator body Iiib of effect I62, the portion of the liquor vaporized within the tubes being separated from the liquor in its vapor separator chamber I221. The separated liquor leaves body Iilb through pipe HM and is transferred by transfer pump I I2a and pipe I Ida to the bottom of the evaporator body Illa of the first effect I08.

A further quantity of the liquor is vaporized within the tubes of evaporator body Illa and the resulting vapor-liquor mixture is separated in its vapor separator chamber IZa. Concentrated liquor leaves the body Illa through the outlet pipe I22.

Vapors from the vapor separator chamber I2a of body lea are conducted through a vapor pipe I26 to the entrainment separator ISb of the body ilib wherein entrained liquor is separated from the vapors. These vapors pass over the rim of the cylindrical baiiie 38b into contact with the tube bundle in the body Iflb and the separated liquor flows through pipe I2! into the concentrated liquor pipe I22.

Vapors from the vapor separator chamber I2b of the body Itb are conducted through a pipe 52 m to the entrainment separator of body Iflc of the next effect I65 where entrained liquor is separated from these vapors in the same manner as before. The vapors then pass into contact with the tube bundle of body I80 and the separated liquor is withdrawn through pipe I 2Ia and flows into pipe II Ba and thence through pump HM and pipe I I l to the bottom of body Ilia.

Vapors from the vapor separator chamber of the body lilcpass through a tangential vane, or other conventional, entrainment separator I36 on the top of body We and thence through vapor pipe I32 to a barometric or other condenser (not shown).

Vapors evolved in the liquor flash chamber I8a of the body Iiic are removed near the top of the liquor flash chamber and pass through pipe I34 to the separating chamber I20 or directly to the vapor pipe I32. If desired, a pressure differential may be maintained by a restriction or check valve (not shown) in the connecting pipe I34 Steam is supplied to the system and particularly to evaporator body I011. through a, steam inlet pipe I36. The steam flows into contact with the tube bundle of body Illa and is-condensed on the outer surface of the tubes, the condensate being collected near the bottom of the body Ifla and removed through pipe I38. Since the condensate in thefirst eifect is free from contaminants that are sometimes present in the vapor of the liquor being evaporated, it is desirable that the condensate from the first effect be segregated and not passed on to a subsequent effect where it would mix with other vapor condensate. Any condensate collecting in the chamber Ifia may be drained off through outlet Ma or an internal opening may be provided through flange 38a to drain the condensate to the bottom of the tube bundle where it is drawn off from outlet 66 through pipe I38.

The condensate collecting at the bottom of evaporator body Iiib of efiect IE2 is transferred through pipe I iii to the condensate flash chamber of body We. Since the steam, spaces I3 and Id of later effects, such as Iii l, are normally maintained at lower pressure than the corresponding space in preceding eifects (in the triple effect evaporator shown), a portion of the condensate entering the condensate flash chamber 20 of the third effect Iii i will vaporize and pass into contact with its tube bundle, The unvaporized condensate flows to the bottom of the body I where it mixes with condensate from the tube bundle of that body and the mixed condensate is withdrawn through a pipe I62 by a condensate transfer pump Hid.

From the foregoing description it is apparent that an evaporator body constructed in accordance with the present invention may be effectively incorporated in a multiple efiect evaporating system to provide a number of important advantages over previously proposed constructions. The principal evaporator elements of each effect are so combined in a compact unitary structure as to provide a self-contained, self-supporting unit that may be conveniently handled during installation. The self-supporting feature eliminates thenecessity for special structural steel supports and the expense incident to the erection of such supports. This self-supporting feature is particularly advantages where the evaporator is to be installed outside of a building and no building structure is available for supporting the evaporator unit or units. The arrangement of the entrainment separator and flash chambers in the form of annular chambers surrounding the tube bundle results in eiiicient utilization of the available space within the evaporator body and desired vapor flow parallel to the tubes of the tube bundle.

Further, the present construction provides flexi-bility in manufacture. Thus each of the chambers located adjacent the tube bundle, i. e., the entrainment separator, the liquor flash chamber and the condensate ffiash chamber may' be omitted from or incorporated in a particular evaporator body with special advantages as desired :but without interfering with the essentially self-contained and self-supporting character of the structure. If .desired different portions of the evaporator unit, such as the vapor separator chamber, may be separately fabricated and connected by fianges or in another suitable manner to facilitate shipment and erection.

We claim:

1. A unitary evaporator body adapted to be used in a multiple effect evaporating system for evaporating one :or more components of a solution, said evaporator body comprising upper and lower spaced tube sheets, a plurality of tubes mounted'at their ends in said tube sheets to form a tube bundle, a casing substantially enclosing said tube bundle, said casing extending substantially above said upper tube sheet and having a closed upper end that defines with the upper portion of the casing and the upper tube sheet a vapor separator chamber, cylindrical wall means surrounding said tube bundle and positioned close thereto, an annular partition extending from said wall means to said casing and defining with said wall means and easing an annular entrainment separator chamber surrounding said tube bundle, said separator chamber being open at its top to communicate with the tubes of said tube bundle, a tangential inlet connection formed in that portion of the casing that constitutes the outer wall of said annular chamber and through which a fiuid mixture may be tangentially introduced into said chamber for separation, and an outlet connection formed in said casing near the bottom of said chamber for removal of separated liquid from said separator chamber and evaporator body, the diameter of the portion of said casing that partially defines said annular chamber being sufiiciently greater than the diameter of said wall means to provide an efficient separating space in said separator chamber.

2. A unitary evaporator body adapted to be used in a multiple effect evaporating system for evaporating one or more components of a solution, said evaporator body comprising upper and lower spaced tube sheets, a plurality of tubes mounted at their ends in said tube sheets to form a tube bundle, a casing substantially enclosing said tube bundle, said casing extending substantially above said upper tube sheet and having a closed upper end that defines with the upper portion of the casing and the upper tube sheet a vapor separator chamber, cylindrical wall means surrounding said tube bundle and positioned close thereto, a first annular partition extending from said wall means to said casing and defining with said wall means and casing a first annular separator chamber surrounding said tube bundle, said separator chamber being open at its top to communicate with the tubes of said ;tube bundle, a tangential inlet connection formed in that portion of the casing that constitutes the outer wall of said annular chamber and through which a fluid mixture may be tangentially introduced into said first chamber for separation, an outlet connection formed in said casing near the bottom of said first annular chamber for removal of separated liquid from said first annular chamher and evaporator body, a second partition between said wall means and casing below said first partition and defining with said first partition casing and wall means a second annular 8 chamber, said :second annular chamber being provided with an :inlet connection-and a pair of outlet connections formed in that portion of said casing that constitutes the outer wall of said second annular chamber, one of said pairof outlet connections being located near the top of said second chamber and the other being located near the bottom of said second chamber, and the diameterof the portion of said casing partially l defining said two annular chambers being sufficiently greater than the diameter of said wall means to provide an efiioient separating space in said annular separator chambers. 3. A unitary evaporator body adapted to be 5 used in a multiple effect evaporating system for evaporating one or more components of a solution, said evaporator body comprising upper and lower spaced tube sheets, a plurality of tubes mounted at their ends in said tube sheets to form a tube bundle, a casing substantially enclosing said tube bundle, said casing extending substantially above said upper tube sheet and having a closed upper end that defines with the upper portion of the casing and the upper tube sheet a vapor separator chamber, a first cylindrical wall gmember surrounding said tube bundle and positioned close thereto, an annular partition extending from said wall member to said casing and defining with said first wall member and casing an annular entrainment separator chamber surrounding said tube bundle, said separator chamher being open at its top to communicate with the tubes of said tube bundle, a tangential inlet connection formed in the portion of the casing that constitutes the outer wall of said first annular chamber and through which a fluid mixture may be tangentially introduced into said chamber for separation, an outlet connection formed in said casing near the bottom of said chamber for re moval of separated liquid from said first annular chamber and evaporator body, a second annular wall member positioned below said first wall member and cooperating with said casing to define a second annular chamber surrounding said tube bundle and open at its top to communicate with tubes of said tube bundle, said second annular chamberhaving an inlet connection formed in its outer wall and a drain connection near the bottom thereof for removal of separated liquid, the diameter of that portion of said casing defining said first and second annular chambers being sufiiciently greater than the diameter of said wall members to provide an eificient separating space in said two annular chambers.

4. A unitary evaporator body adapted to be used in a multiple efiect evaporating system for evaporating one or more components of a solution, said evaporator body comprising upper and lower spaced tube sheets, a plurality of tubes 69 mounted at their ends in said tube sheets to form a tube bundle, a casing substantially enclosing said tube bundle, said casing extending substantially above said upper tube sheet and having w a closed upper end that defines with the upper portion of said casing and the upper tube sheet a vapor separator chamber, cylindrical wall means surrounding said tube bundle and positioned close thereto, and a plurality of annular partitions extending from said wall means to 70 said casing and defining with said well means and said casing three vertically spaced annular separator chambers surrounding said tube bundle, each of said annular chambers being provided with an inlet connection formed in said casing for admission of a fluid mixture to the chamber,

a first outlet near the top of said chamber for removal of separated vapor therefrom and a second outlet near the bottom of said chamber for removal of separated liquid therefrom.

5. An evaporator body according to claim 4 and wherein the upper and lower of said three annular chambers are open at the top to communicate with the tubes of said tube bundle, the uppermost of said three annular chambers is provided with a tangential inlet connection, and the diameter of said casing is uniform throughout its height.

6. A unitary evaporator body adapted to be used in a multiple efiect evaporating system for evaporating one or more components of a solution, said evaporator body comprising upper and lower spaced tube sheets, a plurality of tubes mounted at their ends in said tube sheets to form a tube bundle, a vertical cylindrical casing having a uniform diameter substantially greater than the diameter of said tube bundle and substantially enclosing said tube bunde, said cylindrical casing extending substantially above said upper tube sheet and having a closed upper end that defines with the upper portion of the casing and the upper tube sheet a vapor separator chamber, cylindrical wall means surrounding said tube bundle and positioned close thereto, an annular partition extending from said wall means to said 10 casing and defining with said wall means and casing an annular separator chamber surrounding said tube bundle, said separator chamber being open at its top to communicate with the tubes of said tube bundle, a, tangential inlet connection formed in the portion of said casing that forms the outer wall of said annular chamber and through which a fluid mixture may be introduced into said chamber for separation, and an outlet connection formed in said casing near the bottom of said annular chamber for removal of separated liquid therefrom, the diameter of said casing being sufiiciently greater thanthe diameter of said wall means to provide an efiicient separating space in said separator chamber.

' HAROLD E. JACOBY.

CHARLES P. NILAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,735,980 Sadtler Nov. 19, 1929 1,750,306 Harris Mar. 11, 1930 1,864,349 Grover June 21, 1932 2,181,750 Walker 1 Nov. 28, 1939

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