US2442898A - Method for quenching fluids - Google Patents

Description

June 8, 1948. B. G. MAGUIRE METHOD FOR QUENCHING FLUIDS Filed July 2, 1945 INVENTOR B. G MAGUIRE BY ATI' OR EYS Patented June 8, 1948 UNITED METHOD FOR QUENCHING FLUIDS Bernard G. Maguire, Kansas City, Mo., assignor to Phillips Petroleum Company, a corporation of Delaware Application July 2, 1945, Serial No. 602,884

2 Claims. 1

This invention relates to the quenching of hot hydrocarbon fluids. In one of its more specific aspects it relates to an improved method for quenching hot hydrocarbon fluids by th use of an improved quench oil injection fitting. My improved fitting may be used for the quenching of hot vapors as well as for the quenching of hot liquids in transit.

Quenching devices for the instantaneous cooling of liquids, or for the rapid cooling of vapors with or without condensation are common in the art. The main object of most older quenching methods has been with respect to the speed or rapidity ofv the cooling, and for the most part, apparatus which promoted the more rapid cooling or quenching was considered to be the more desirable.

I have found in certain cases and under certain conditions that the conventional rapid quench of hot streams of fluids is a marked disadvantage. When streams of hot, liquid, cracked hydrocarbons which contain tarry, coke-forming materials, are quenched, these materials tend to precipitate out due to the decrease in temperature. Quench oils usually are relatively good solvents for such precipitated materials. If, however, the cracked stock is high in such constituents, the quench oil may not be able to dissolve the tarry, coke-like materials as fast as they are formed. The overall result of such conditions will be a deposition of coke on the walls of the transfer line on the downstream side of the point of quenching. Ultimately the pipe may become suificiently choked that a shut down and cleancut is necessitated. Too rapid cooling of vapor streams may cause similar results.

To overcome such impractical operation I have devised means for quenching or cooling such hydrocarbon streams which means accomplishes the desired cooling and at the same time prevents coking of the transfer line following the point of quench.

One specific object of my invention is to provide ,a quench fitting so designed as to produce as little turbulence as possible at the point of quench.

Another object of my invention is to provide a quench fitting designed for the addition of a quenching material in a direction as nearly parallel as possible to the direction of flow of the fluid being quenched.

Still other objects and advantages will-be apvide an apparatus for the rapid quenching of hot hydrocarbon fluids and still prevent deposition of coke on the downstream side of the quenching apparatus.

Another object of my invention is to provide a quenching fitting for use in hydrocarbon cracking furnace transfer lines for cooling streams of cracked oils or vapors without substantial precipitation and deposition of coky materials on the inside. walls of said transfer lines.

Still other objects and advantages will be apparent to those skilled in the art from a careful study of the following detailed description taken in conjunction with the attached drawing which respectively describes and illustrates a preferred embodiment of my invention, and wherein Figure 1 is a longitudinal, elevational view, partly in section, showing one type of my quenching apparatus.

Figure 2 is an end view of the quench fitting looking from the line 2-2 of Figure 1 in the direction of the attached arrows.

Figure 3 is a cross sectional view of the quench fitting taken on the line 33 of Figure 1.

Figure 4 is a longitudinal sectional View of a second type of quenching apparatus.

Referring to the drawing and specifically to Figure l, numeral H refers to the quench fittin proper while numeral l2 refers to an auxiliary fitting. The quench fitting is composed mainly of a body I3 and two end flanges I4 and it. A free and unobstructed opening it is the conduit through which a stream of hot fluid to be quenched flows. The fluid flows in the direction indicated.

The main body of the fitting is provided with some channels 11 through which quench oil may flow. In the fitting illustrated by Figures 1, 2 and 3, I have shown four of these channels. It will be obvious that the fitting member may be made to contain as many of these channels as desired, ranging from one to any number as four, six or even eight, or in very large sized equipment a relatively large number may be required. The angle I8 which the longitudinal axes of the channels I! make with the conduit l6 should prefr b be as small as is consistent with good mechanical construction. The outer ends of these channels terminate in openings l9. The inner ends of the channels terminate in slots 20 adjacent the fluid conduit. The flange l4 contains bolt holes for securing the fitting member to its operating position in a fluid carrying transfer pipe. Since the endflange I5 is of a greater diameter than is normal for the conduit It, the auxiliary flange reducing fitting I2 is used, and this fitting terminates in a flange .2I to which ma be attached pipe fittings of standard dimensions. Thus in the overall installation of my quenching apparatus, the assembly illustrated in Figure 1 is simply inserted into a transfer line at a point at which it is desired to quench the fluid in transit.

As an alternative the auxiliary flanged fitting l2 may be omitted if other means is available for attaching the large end flange Hi to the flange of a transfer pipe 22. This auxiliary flanged fitting l2 serves no purpose as regards the quenching operation, but is merely a reducing flange. The joint between this reducing flange l 2 and the flange i5 is sealed by use of a gasket 23.

The quench fitting embodiment illustrated in Figure 4 is intended to function in substantially the same manner as does the embodiment of Figure 1. The only difference is in its mechanical construction. In Figure 4, the quench member is composed of two parts, these being identified by reference numerals 25 and 26. The outer housing member 25 is composed of a standard diameter flange 21, an outer conical shaped housing 28, and a large diameter flange portion 29 coring holes 30 threaded to take pipe fittings. The inner member 26 is composed of two parts identified :by numerals 3| and 32. The conical portion referred to by numeral 3| may be considered what would be left from a cone by having its longitudinal axis drilled out and the base of the remaining annular portion attached to a flange, identified by numeral 32. With this type of quencher a reducing flange I2 is needed in like manner as was explained in reference to Figure 1. This reducing flange and the quench member are held in fluid tight contact by bolts 34 and a gasket 35. A fluid tight seal is also necessary between the flanges 32 and 29, and accordingly a gasket 33 is inserted. The several large diameter flanges 29, 32 and flange member l2 may be held together by a single set of flange bolts, as bolts 34.

As mentioned hereinbefore, my apparatus may be used in the quenching of hot vapors as well as for quenching hot liquids. In either case, the quench fitting H or 25 and a reducing flange member 52 are merely inserted into a transfer line at the desired point of quench.

For the quenching of hot liquids in transit, a quench oil or other desired liquid is forced through the quench oil inlets IQ (of Figure 1), into the fittings against transfer line pressure. The oil flows through the channels I l and enters the conduit it at points 20. The quench oil entering the conduit [6 is swept in a downstream direction by the hot oil to be quenched. Since the quench oil enters the conduit I6 at a relatively small angle with the conduit, mixing of the two oils is slight, and for the most part the central core of hot oil and the added quench oil fiow downstream in substantially a streamline manner. The slot openings'Zll are intended to be of such length that four of them as shown in Figures 1 and 2 cover substantially the entire circumference of the conduit 16. Thus the relatively cool quench oil entering the conduit l6 through the slots 20 forms a layer of cool oil adjacent the side wall of the transfer pipe.

While the quench oil follows the pipe walls for quite some distance before mixing with the hot oil in transit, yet the time period prior to complete mixing is relatively short since hot oil transfer line velocities are rather high.

These quench fittings may be used for adding quench oil to streams of hot vapors as well as to liquids or even to streams containing liquids and vapors. The mechanism of operation of my quench fitting in these several cases is substantially the same, that is, cool quench oil enters and is carried downstream adjacent the pipe walls.

While quenching liquid is in transit slowly, tarry and coke-forming constituents are precipitated rather slowly due to a relatively slow drop in temperature. In addition, little turbulence is caused at the point of quench because the direction of flow in the transfer line is not changed. The inner diameter of the transfer conduit is not changed as is the case when using conventional quench fittings. The quench oil on flowing downstream in a streamline manner sweeps the walls of the transfer line and prevents deposition of coke and coke-forming materials. My quenching is not immediate and in fact is intended to be relatively slow. This type of quenching results in a smaller concentration of coke and tarry material being precipitated in the case of liquids, and condensed in the case of vapors, per length of transfer line and allows these undesirable materials to be swept away by the stream rather than to be deposited on the walls of the transfer line.

In the quenching of hot liquid or vapor streams it is believed that the actual precipitation or condensation of tarry coke-forming particles cannot be prevented in any manner. The amount of such material formed would appear to be dependent upon the type of stock being quenched, its composition, temperature and pressure and quench temperature rather than upon the speed of quench. Thus by my slow quench the precipitated tarry materials may be actually dissolved and/or carried away by the wall sweeping action resulting from the particular design of my apparatus.

My fitting was designed primarily to get away from the conventional T injection fitting wherein the quench oil and transfer line effluent meet at right angles causing what I consider undue turbulence at that point. I believe that an added advantage of my design is that the quench oil will sweep the walls of the transfer line downstream from the injection point and thereby cool the main body of the furnace eflluent over a longer section of transfer line. Since the time of quenching is longer and therefore the rate of tar and coke precipitation accordingly less than that involved when using conventional quench fittings, the quench oil has less coke formers to dissolve in a given interval of time.

My fittings are suitable for use with any type of quench oil it is desired to use. To those skilled in the art it is well known that many different vapors, oils and other liquids need to be quenched for various reasons, and I have found my fittings and the principles embodied therein have wide application. For example, my fittings may be used for the quenching of high temperature oils, such as hydrocarbon oils, hydrocarbon vapors, or mixtures of liquid and vaporous hydrocarbons; water may be added to liquid or vaporous materials, or one liquid chemical to another liquid or vapor wherein final mixing should not be extremely rapid. v

My fittings may be made of any size desired depending upon its intended use; For example, a fitting for installation in a two inch diameter pipe should have a conduit (16) diameter of about two inches. The size of the inlet ports l9 of Figure 1 and of ports 30 of Figure 4 will be dependent upon the volume flow of quench oil required for a given problem as well as upon the number of such ports in the fitting. The angle between the channels H and the longitudinal axis of conduit 16 of Figure 1 and the corresponding angle between the annular conduit space 37 and the longitudinal axis of the conduit 36 should be as small as possible consistent with good mechanical construction. The smaller this angle the more efiicient will be the washing action of the added quench oil and the slower will be the mixing of the quench oil and the material being quenched.

Materials of construction may be selected from among those commercially available and found to be suitable for the purpose at hand. For contacting one hydrocarbon oil with another, ordinary steel may serve the purpose. For handling corrosive chemicals, special corrosion resistant material should be used.

I do not wish to limit my invention in any manner by the above given explanation or theory as to how my quench fitting functions, since the same was given merely as a means of illustrating the principles involved and preferred embodiments of my invention. It will be obvious to those skilled in the art that many modifications in design and construction may be made, as well as many additional applications for its use without departing from the intended scope and spirit of my invention.

I have described two embodiments of a quench fitting which main body member has a conical shape or rather that of a truncated cone. This particular shape or form, however, plays no part in my invention since the actual exterior shape or form is immaterial. This body member may be cylindrical in form, or rectangular, or hexagonal, or any other form, likewise it may be conical or rather that of a truncated cone or even that of a truncated pyramid of as many sides as desired. The only reason for using the pyramidal or conical form is as a means of saving of material and therefore cost of construction.

If the body member is square or hexagonal in cross section then the channels I! (of Figures 1, 2 and 3) may well be directly under the edges of said figures for structural reasons.

If both ends, that is the flanged ends, of my quench fittings are of too great diameter to be attached to standard pipe fittings, then reducing flanges will be needed. By using a conical or pyramidal form of fitting a downstream end reducer flange will usually not be needed since this end of the fitting will fit to standard pipe flanges. However, a reducing flange mechanism will usually be required on the upstream end of my quench fitting.

What I claim is:

1. The method of quenching with a first cooler fluid, a second hotter fluid flowing in a pipe which second fluid during quenching tends to precipitate solids on the inner surfaces of said pipe, and which solids are relatively slowly soluble in the first fluid, which comprises passing the second fluid through the pipe in substantially streamlined flow, injecting the first fluid in the form of a substantially annular sleeve between the second fluid and the walls of the pipe and in a direction of flow concurrent with the direction of flow of said second fluid, said first fluid meeting said second fluid at such a small angle of contact that substantially no turbulence at the point of injection occurs, confining the second fiuid and any solids precipitated therein within said annular sleeve of cooler fluid until at least a cooler portion of said pipe is reached whereby adherence of said solids to said pipe is substantially reduced, and subsequently mixing said first and second fluids together slowly whereby said first fluid may dissolve some of said precipitated solids before all of said solids have been precipitated whereby the adherence of said solids to the pipe walls is substantially reduced.

2. The method of quenching with a first cooler fluid, a second hotter fluid flowing in a pipe which second fluid during quenching tends to precipitate solids on the inner surfaces of said pipe, and which solids are relatively slowly soluble in the first fluid, which comprises passing the second fluid through the pipe in substantially streamlined flow, injecting the first fluid in the form of a substantially annular sleeve between the second fluid and the walls of the pipe and in a direction of flow concurrent with the direction of flow of said second fluid, said first fluid meeting said second fluid at such a small angle of contact that substantially no turbulence at the point of injection occurs, and that the second fluid continues to flow in a streamlined manner surrounded by the streamlined flow of the annular sleeve of said cooler fluid, confining the second fluid and any solids precipitated therein within said annular sleeve of cooler fluid until at least a cooler portion of said pipe is reached whereby adherence of said solids to said pipe is substantially reduced, and subsequently mixing said first and second fluids together slowly whereby said first fluid may dissolve some of said precipitated solids before all of said solids have been precipitated whereby the adherence of said solids to the pipe walls is substantially reduced.

BERNARD G. MAGUIRE.

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

UNITED STATES PATENTS Number Name Date 1,655,053 Fleming Jan. 3, 1928 1,957,946 Donnelly May 8, 1934 1,966,113 Booth et al July 10, 1934 2,165,880 Arkin et a1. July 11, 1939 2,310,265 Sweeney Feb. 9, 1943 FOREIGN PATENTS Number Country Date 354,393 France Oct. 4, 1905 409,875 Great Britain May 10, 1934 Certificate of Correction Patent No. 2,442,898. June s, 1948.

BERNARD G; MAGUIRE It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 1, line 53, strike out Still other objects and advantages will be apand insert instead Still another object of my invention is to pro-; column 3, line 52, for fittings read fitting; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record oi'the case in the Patent Oflice.

Signed and sealed this 31st day of, August, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

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