US3322647A

US3322647A - Quenching apparatus

Info

Publication number: US3322647A
Application number: US385150A
Authority: US
Inventors: Lloyd R Calaway
Original assignee: Monsanto Co
Current assignee: ConocoPhillips Co
Priority date: 1964-07-27
Filing date: 1964-07-27
Publication date: 1967-05-30
Anticipated expiration: 1984-05-30
Also published as: GB1113266A; DE1501402B2; DE1501402A1; IL24032A

Description

Q 16? L. R. CALAWAY QUENCHING APPARATUS 5 Sheets-Sheet 1 Filed July 27. 1964 FIGURE I INVENTOR. Lloyd R. Culowuy ATTORNEY L R. CALAWAY QUENCHING APPARATUS 3 Sheets-Sheet 2 Filed July 27, 1964 FIGURE 2 INVENTOR. Lloyd R. Cutaway BY zzfi ATTORNEY 3Q, 1967 L. R. CALAWAY QUENCHING APPARATUS 3 Sheets-$heet :5

Filed July 27. 1964 FIGURE 3 INVENTOR. Lloyd R. Co luwoy 3,322,647 Patented May 30, 1967 3,322,647 QUENCHHNG APPARATUS Lloyd R. Calaway, Galveston, Tex, assignor to Monsanto Company, St. Louis, Mo., a corporation of Delaware Filed July 27, 1964, Ser. No. 385,150 6 Claims. (Cl. 196-140) The present invention relates to an apparatus and method for the quenching or rapid cooling of high temperature fluid media. More particularly, the present invention relates to an apparatus and method for quenching high temperature fluids by contact with quench liquids whereby coking and metal fatigue are substantially reduced.

In many industrial processes, it is necessary to rapidly quench or cool hot product streams. Such is relatively common in the thermal cracking of hydrocarbons in which vaporized hydrocarbon products pass from the cracking zone at rather high temperatures. Other processes employing high temperatures in the reaction zone also produce reaction products which must be rapidly cooled to prevent further reaction. Many problems have been encountered in attempting to quench these high temperature product streams. Rapid cooling of high temperature, high carbon content, product streams containing hydrocarbons or derivatives of hydrocarbons produces coking which has been known to completely plug take-off lines from reaction zones in a matter of minutes. Also, where there is rapid cooling or interference with the flow of the product stream, considerable metal fatigue often occurs which materially shortens the usefulness of the piping or containing means of which the metal is a part and also increases the danger of blow-outs in such equipment with the attendant damages.

One of the better means known for rapidly quenching product streams involves the use of a quench medium, usually a liquid, which is brought into contact with the high temperature product stream to absorb heat from the product stream and cool the same. However, as heretofore practiced, the use of quench liquids has resulted in coking in the quench zone and significantly contributed to metal fatigue of the quench apparatus. In fact, quench liquids have actually increased the coking problem since in many instances much of the quench liquid is vaporized by heat exchange with the product stream thereby allowing fall out and deposition of the solids which may be found in commercially practical quench liquids. Further, in presently practiced quenching means wherein a liquid quench is used, the degree of quenching is quite often inadequate.

It is an object of the present invention to provide a new and novel quenching apparatus and method for quenching high temperature fluids. Another object of the present invention is to provide a new and novel apparatus and method for quenching high temperature fluids in which a liquid quench medium is employed. Still another object of the present invention is to provide a new and novel apparatus and method for quenching high temperature fluids whereby the deposition of foreign deposits such as coke, carbon and solids precipitated from the quench medium or high temperature fluid medium is substantially reduced. A further object of the present invention is to provide a new and novel apparatus and method for quenching high temperature fluids whereby metal fatigue in the quench zone is materially reduced. Additional objects will become apparent from the following description of the invention herein described.

According to the present invention, there is provided a method of quenching high temperature fluids within a tubular quench chamber wherein said high temperature fluid to be quenched is contacted with a quench liquid, said method comprising forming a divergent spray of said quench liquid and injecting a stream of high temperature fluid to be quenched into said divergent spray of quench liquid from a point adjacent to but out of contact with said divergent spray and without substantial cooling of said fluid to be quenched prior to contact with said quench liquid in a manner such that a substantial portion of said stream of fluid to be quenched intersects the outer lateral surface of said divergent spray of said quench liquid at an angle approximating degrees, said divergent spray of quench liquid being in substantial contact with the lateral walls of said quench chamber at all points downstream from the point of injection of said stream of high temperature fluid to be quenched into said divergent spray of quench liquid.

Also, according to the present invention, there is provided an improved apparatus for quenching high temperature fluids by contact with a quench liquid, said apparatus comprising a tubular quench chamber, an inlet means for introducing said quench liquid into said chamber in the form of a divergent spray to contact at least a portion of the lateral walls of said quench chamber, an injection means insulated against the loss of heat for introducing a stream of high temperature fluid to be quenched into said chamber into contact with said divergent spray of quench liquid so that a substantial portion of said stream of fluid to be quenched intersects said divergent spray of quench liquid at an angle approximating 90 degrees, said injection means being arranged upstream from the point where said quench liquid contacts the lateral walls of said quench chamber and out of contact with said divergent spray of quench liquid but adjacent thereto, and an outlet means for withdrawing quenched fluid from said chamber.

To further describe the present invention, reference is made to the accompanying drawings.

FIGURES 1 through 3 are schematic representations of three different embodiments of the present invention.

Referring to the drawings in which the same reference characters are used throughout to denote like parts of the present invention, a high temperature fluid such as a vaporized normally-liquid hydrocarbon stream is introduced into tubular quench chamber 10 by means of one or more injection tubes 11 extending into tubular quench chamber 10 and in open communication with tubular quench chamber 10 by means of open end 112. Directional arrows indicate the direction of flow of the high temperature fluid within injection tube 11. Quench liquid is introduced into tubular quench chamber 10 by means of line 13 and spray nozzle 14. The type and arrangement of spray nozzle 14 must be such that the quench liquid is injected into quench chamber 10 in the form of a diverging conical-shaped spray in a manner so that a portion of the outer lateral surface of the spray intersects the flow of the high temperature fluid to be quenched at approximately a right angle immediately upon introduction of the hot fluid into quench chamber 10 through open end 12 of the injection tube 11. The broken lines in the accompanying drawings illustrate the conical-shaped spray of quench liquid from nozzle 14. Quench nozzle 14 is further positioned within quench chamber 10 so that the portion of the quench liquid not vaporized in quenching the high temperature fluid strikes the tubular wall of quench chamber 10 downstream from the point of introduction of the high temperature fluid into quench chamber 10 from injection tube 11. The quenched high temperature fluid and vaporized quenched liquid pass from quench chamber 10 through line 15. By this method and apparatus the high temperature fluid is rapidly cooled and carbon formation and deposition in the quench chamber is substantially reduced. Also, because of the efficiency of the rapid cooling and the wetting of the wall of the quench chamber downstream from the point of introduction of the hot fluid, metal fatigue is very significantly reduced due largely to lower andmore uniform surface temperatures of the walls of the quench chamber.

As shown in FIGURE 1, injection tubes 11 are preferably encased within cylindrical arms 16 for a substantial distance extending from quench chamber so as to provide an annular space 17 to insulate injection tubes 11 and prevent cooling of injection tubes 11. Injection tubes 11 terminate in open end 12 at a point outside quench tube 10 but within arms 16 and do not protrude into quench chamber 10. Thus, contact of quench liquid with the surface of injection tubes 11 is avoided. It may also be seen in FIGURE 1 that the conical spray from quench nozzle 14 is substantially coaxial with quench tube 10.

Referring particularly to FIGURE 1 which presents a preferred embodiment of the present invention, a means of purging annular spaces 17 surrounding injection tubes 11 is provided. This means comprises one or a plurality of purge inlets 1-8 for introducing a purge medium into annular spaces 17. The number and arrangement of inlets 18 should be such as to produce a relatively uniform disl'lllblltlOIl of the purge medium throughout annular spaces 17. The purging medium is supplied via lines 19.

FIGURES 2 and 3 present an embodiment of the present invention wherein the quench liquid is introduced from the lateral side of tubular quench chamber 10 instead of from one end of the quench chamber. As in FIG- URE 1 injection tube 11 is insulated by an annular space 17 but this annular space is formed between the walls of quench chamber 10 and injection tube 11. Quench line 13 and nozzle 14 are arranged such that their axis is at substantially a 45 angle with the axis of said tubular quench chamber 10. Open end 12 of the injection tube 11 is located just above the point where quench liquid is introduced through quench line 13 so as to not be in contact with quench liquid. The upper surface of the conical spray of quench liquid intersects the flow of high temperature fluid to be quenched at an approximate right angle because quench line 13 is arranged at an approximate 45 angle to the axis of quench tube 10; however if desired, quench line 13 may be arranged perpendicular to the axis of quench tube 10 with nozzle 14 mounted at an angle to the axis of quench tube 10 to obtain the same relationship upon the intersection of the spray of quench liquid with high temperature fluid. As may be seen in FIGURE 2, injection tube 11 extends coaxially into quench chamber 10.

In FIGURE 3, an embodiment of the invention similar to the embodiment of FIGURE 2 is illustrated wherein the high temperature fluid to be quenched i introduced at one end of quench chamber 10; however, in this embodiment the quench liquid is introduced through a plurality of nozzles 16 set in the lateral wall of quench chamber 10 to uniformly wet the walls of quench chamber 10 downstream from the point of introduction of said high temperature fluid medium. A further feature of the embodiment of the present invention illustrated by FIGURE 3 is the expansion in the diameter of quench chamber 10 downstream from injection tube 11.

In the practice of this invention a substantial proportion of high temperature fluid to be quenched or cooled must be introduced into contact with the external surface of the divergent spray of quench liquid at approximately a 90 angle in order to obtain the advantages of this invention. Intersection at exactly 90 is not required and the angle may vary from 75 up to 105 and still some improvement in quenching obtained. The quench liquid is usually introduced as a divergent spray of liquid; that is, as a conical spray. The high temperature fluid to be quenched is preferably brought into contact with the quench liquid without much divergence of flow; however,

4- the fluid to be quenched may be in the form of divergent flow provided that a substantial proportion of the fluid can still be brought into contact with a quench liquid at approximately a angle.

It is necessary in the present invention to provide a means of insulating the outer surfaces of the injection tubes to reduce the loss of heat from the injection tubes. In the present invention, this insulating means is most often an annular free space between the walls of the quench chamber and the injection tubes. However, insulating materials may be used instead of or in combination with the annular free space. The type and kind of insulation will vary with the temperatures and fluid media to be quenched as well as with the quench medium. Determination of the type and kind of insulation is well within the ability of those skilled in the art. The insulating materials, if used, preferably do not fill the annular space surrounding the injection tube. It is preferable that little or no insulating material be used and that the annular space he left open in order to allow flow of a purge medium around the injection tubes and to provide for minimum heat loss from the injection tubes.

In practicing the present invention in the preferred manner wherein annular space surrounding the injection tubes and a means for purging said annular space is provided, a wide variety of materials may be used as a purge medium. Most often, an inert gaseous material is used. The purpose of the purge medium is to keep the annular spaces surrounding the injection tubes free of coke and carbon. Although the present invention results in substantially decreased carbon formation and deposition, some carbon is formed on the walls of the quench chamber adjacent the open ends of the injection tubes, especially when the fluid to be quenched is at very high temperatures. After a period of time, this carbon formation will become such as to close off an annular space and increases the loss of heat from the injection tubes. Introduction of the purge medium into the annular spaces sweeps these carbon or other deposits, if any, out into the quench chamber as it forms thus preventing a carbon buildup. The preferable purge media are nitrogen or steam with steam generally preferred over nitrogen.

The apparatus and method of the present invention have a wide variety of applications in providing for the quenching of high temperature fluids. Such fluids may either be a gas, a gas containing entrained liquid, a vaporized liquid, or a liquid. Most often, the fluid is a substantially vaporized normally liquid hydrocarbon stream. In practice, the present invention is useful in quenching or rapidly cooling process streams wherein a relatively large and very rapid decrease in temperature of the process stream is needed in order to either stop further reaction or for other considerations. A particularly useful application of the present invention is in the quenching of the product of relatively high temperature cracking operations, particularly the thermal cracking of petroleum feedstocks.

The choice of a quench liquid for use in the present invention will vary substantially depending upon the fluid media to be quenched, the condition of its arrival in the quench zone, i.e., temperature, etc. as well as the desired degree of quenching. The selection of a quench liquid for a particular utility of the present invention is well within the ability of those skilled in the art. In practicing the present invention in accordance with a-particular application thereof whereby it is used in the quenching of the product of relatively high temperature cracking operations, particularly thermal cracking, it is usually preferred that the quench liquid be a hydrocarbonaceous liquid.

In order to demonstrate the efficacy of the present invention, comparison was made between two quenching systems, one constructed in accordance with the present invention and the other constructed somewhat similarly but without the present invention. The quench system constructed in accordance with the present invention was substantially the same as that shown in FIGURE 1 of the drawings. The other quench system was constructed quite similar to FIGURE 1 with two major exceptions. In describing this other quench system, reference will be made to FIGURE 1. In this quench system, no injection tube 11 surrounded by annular space 17 was provided. Rather, the material to be quench was introduced directly through arms 16. Further, in this more conventional system, quench nozzle 1% was not positioned such as to discharge quench liquid in a manner to intersect the incoming hot liquid at substantially a right angle and at the same time wet the walls of the quench chamber downstream from the point of injection of the hot liquid as provided for by the present invention.

In comparing these two quench systems, a hot reaction product from the thermal cracking of a petroleum condensate was introduced continuously. In each of the systems substantially the same quench oil was introduced into contact with the hot products. It was found that with the quench system lacking the features of the present invention, substantial coking within the quench system occurred in periods ranging from two days to two weeks, while with the quench system constructed and operated in accordance-with the present invention, no significant coking occurred for a period in excess of 9 months. It was further found that metal fatigue as exemplified by extreme metal failure in the conventional quench system occurred at periods ranging from 4 to 7 months, whereas with the quench system of the present invention, no metal fatigue was noted within the 9 months period.

In view of this comparison, it is believed apparent that the present invention provides a significant improvement in the art of quenching high temperature fluid media.

What is claimed is:

1. An apparatus for quenching high temperature fluids by contacting with a quench liquid, said apparatus comprising a tubular quench chamber, a spray nozzle for introducing said quench liquid in the form of a conical spray to contact at least a portion of the lateral walls of said quench chamber, an injection tube coaxially extending into said tubular quench chamber for introducing a stream of high temperature fluid to be quenched into said conical spray of quench liquid so that a substantial portion of said stream of fluid to be quenched intersects a portion of the outer lateral surface of said conical spray of quench liquid at an angle approximating 90 degrees, said injection tube being surrounded by an annular space provided with one or a plurality of purge inlets for introducing a purge medium into said annular space, said injection tube being arranged upstream from the point where said quench liquid contacts the lateral walls of said quench chamber and out of contact with said conical spray of said quench liquid but adjacent thereto, and an outlet means for withdrawing quench fluid from said chamber.

2. The apparatus of claim 1 wherein there are a plurality of purge inlets.

3. The apparatus of claim 1 wherein the angle approximating 90 degrees is within the range of from to 105.

4. An apparatus for quenching high temperature fluids by contacting with a quench liquid, said apparatus comprising a tubular quench chamber, a spray nozzle for introducing said quench liquid in the form of a conical spray which spray contacts at least a portion of the lateral walls of said quench chamber, said spray nozzle being substantially coaxial with said tubular quench chamber, two injection tubes extending into said tubular quench chamber for introducing two streams of high temperature fluid to be quenched into said conical spray of quench liquid so that a substantial portion of said streams of fluid to be quenched intersects a portion of the outer lateral surface of said conical spray of quench liquid at an angle approximating degrees, each of said injection tubes being surrounded by an annular space provided with one or a plurality or purge inlets for introducing a purge medium into said annular space, said injection tubes being arranged upstream from the point where said quench liquid contacts the lateral walls of said quench chamber and out of contact with said conical spray of said quench liquid but adjacent thereto, and an outlet means for withdrawing quench fluid from said chamber.

5. The apparatus of claim 4 wherein there are a plurality of purge inlets.

6 The apparatus of claim 4 wherein the angle approximating 90 degrees is within the range of from 75 to References Qited UNITED STATES PATENTS 2,769,692 11/1956 Heller 23259.5. 2,791,549 5/1957 Iahnig 20848 3,009,783 11/1961 Sheer et a1. 23-259.5 3,015,619 1/1962 Wimmer et al 208-48 3,130,146 4/1964 Plaster 208-106 FOREIGN PATENTS 321,473 11/ 1929 Great Britain.

DELBERT E. GANTZ, Primaly Examiner. H. LEVINE, Assistant Examiner.

Claims

1. AN APPARATUS FOF QUENCHING HIGH TEMPERATURE FLUIDS BY CONTACTING WITH A QUENCH LIQUID, SAID APPARATUS COMPRISING A TUBULAR QUENCH CHAMBER, A SPRAY NOZZLE FOR INTRODUCING SAID QUENCH LIQUID IN THE FORM OF A CONICAL SPRAY TO CONTACT AT LEAST A PORTION OF THE LATERAL WALLS OF SAID QUENCH CHAMBER, AN INJECTION TUBE COAXIALLY EXTENDING INTO SAID TUBULAR QUENCH CHAMBER FOR INTRODUCING A STREAM OF HIGH TEMPERATURE FLUID TO BE QUENCHED INTO SAID CONICAL SPRAY OF QUENCH LIQUID SO THAT A SUBSTANTIAL PORTION OF SAID STREAM OF FLUID TO BE QUENCHED INTERSECTS A PORTION OF THE OUTER LATERAL SURFACE OF SAID CONICAL SPRAY OF QUENCH LIUQID AT AN ANGLE APPROXIMATING 90 DEGREES, SAID INJECTION TUBE BEING SURROUNDED BY AN ANNULAR SPACE PROVIDED WITH ONE OR A PLURALITY OF PURGE INLETS FOR INTRODUCING A PURGE MEDIUM INTO SID ANNULAR SPACE, SAID INJECTION TUBE BEING ARRANGED UPSTREAM FROM THE POINT WHERE SAID QUENCH LIQUID CONTACTS THE LATERAL WALLS OF SAID QUENCH CHAMBER AND OUT OF CONTACT WITH SAID CONICAL SPRAY OF SAID QUENCH LIQUID BUT ADJACENT THERETO, AND AN OUTLET MEANS FOR WITHDRAWING QUENCH FLUID FROM SAID CHAMBER.