US1850429A - Heat exchanger - Google Patents

Description

' Ic. R. WAGNER HEAT EXCHANGER Fild Jan. 29, 1929 4. um. ww n ||||H|||f|||| FIIIIIIIIIIIIII" I I I o ".IIhIIvIIIIIIIII L WIIIIIIIIIIuIII 1Q S HI||,|.n|||||. m MMIII t I I |||I I I "UII'IIWIIWIIIII NI, I Ih I w I I I lnl x March 22, 1932.

Patented Mar. 22, 1932 CARY R. WAGNER, OF CHICAGO, ILLINOIS, .ASSIGNOR T GYRO PROCESS COMPANY, OF

DETROIT, MICHIGAN, A CORPORATION 0F MICHIGAN HEAT EXCHANGER Application led January 29, 1929. Serial No. 335,843.

In a general sense this invention relates to heat exchangers, and particularly to that form of heat exchanger wherein hot vapors are brought into intimate contact with cooler liquids for the dual purpose of sharply decreasing the temperature of the vapors and at the ,same time raising the temperature of the liquids, the fluids being brought into direct-contact with each other to procure leiiicient heat exchange there-between.

It is a primary object of the invention t0 provide an improved heat exchange employing the above principles of operation in connection with vapor phase oil converters. It is known that large quantities of free carbon are liberated from the vapors discharged from high temperature oil converters. As set frth in the patent to J. B. Weaver, No. 1,601,7 86, October 5, 1926, carbon is liberated mainly during the time the temperature of the oil vapors falls from an active converting temperature in excess of 1000o F. to a non-converting temperature not in excess 0f 600 F.

v It is therefore important to redu'ce the time element involved in effecting this cooling of the oil vapors to the greatest practicable extent. The present invention provides an improved structural type of cooler in that 'it is formed to include open vapor passages or chambers from which carbon collecting and obstruction forming elements are eliminated to the end that the vapors may pass freely through the cooler but at a greatly reduced rate of iow as compared with their velocity through the converter, whereby carbon entrainment in the released vapors from the cooler is to all intents and purposes precluded as well as the formation of carbon deposit within the confines of the cooler itself Itis another object of the invention to provide the jet condenser or cooler, comprising .the present invention, with separate outlets for the vapors and the liquid oil, the liquid oil outlet being connected with a pump and filter by which carbon, which collects in the liquid oil, may be removed from the system and prevented from entering other correlatedapparatus.

For a further understanding of the invention reference is to be had to the following description and to the accompanying drawings wherein:

Figure 1 is a diagrammatic view of a vapor phase system ofoil conversion utilizing the improved cooler or jet condenser, comprising the presentinvention,

Figure 2 is a vertical sectional view taken through the cooler,

Figure 3 is a horizontal sectional view taken through the cooler on the line 3 3 of Figure 2.

Referring more particularly to the drawings, the numeral 1 designates the improved cooler vor jet condenser to which the present invention has specific reference. This cooler or condenser is utilized in connection with systems of oil conversion, and particularly those systems wherein the oil undergoing conversion is maintained in the vapor phase and suitably treated so as t'o be rendered adaptable for subsequent use as a motor fuel. To further a more complete understanding of the invention the cooler 1 has been shown as situated in an oil converting system which comprises basically a vaporizer 2. #This vaporizer contains a bank of tubes 3- through which the charging stock of the system is passed and subjected to temperatures suiiiciently high to eiiectvaporiza-tion of the lighter constituents of the charging stock blfit without any appreciable cracking thereo The products discharged from the vaporizer enter an evaporator 4, wherein said products arel fractionated to separate the vaporous and liquid constituents thereof, the liquid constituents being removed from the bottom of the evaporator by way of a pipe line 5 and may thus be permanentlyremoved from the system. The vaporous constituents pass overhead from the evaporator through the pipe line 6 and enter a bank of tubes 7 arranged within a converter 8. Within this converter the oil vapors are subjected to temperatures of the order of 1000 F. or higher, wherein said vapors are subjected to molecular decomposition for arequired period of time, usually not in excess of two seconds. The vapors, immediately upon leaving the converter 8, enter the cooler or vao 'et condenser 1, where said vapors are brought into intimate contact with a body of fresh or cold oil, which may be at atmospheric teniperature or slightly higher. 4By thus Acommg into intimate contact with the liquid oil,

ithe temperature of the vapors leaving the converter' is substantially instantaneously lowered from a highly reactive converting temperature in excess of -1000 F. t0 a nonconverting temperature not in excess of 600 F. This drop 'in temperature occurs substantially instantaneously and, as previously explained, the reasons for this reside in the fact that free carbon. is liberated to the greatest extent in a system of this character during the cooling of the converter vapors between the temperature limits specified. Therefore, the shorter the time element involved in this cooling operation the less is the amount of' carbon formed. This feature has been set forth 'and claimed in the Weaver patent, above identified. The oils which remain in vaporous form at a temperature below 600 F. pass from the cooler 1 by way of a pipe line 9 and enter a fractionating column 10, 4"and after passing through said fractionating column or tower the vapors are conducted by means of a pipe line 11 to condensing or treating apparatus (not shown). The liquid oils which accumulate in the bottom of the cooler or condenser 1 flow by way of a pipe line 12 to thelower portion of the fractionating column in which liquid oil accumulates as a result of fractionation operations. A pipe line- 13 in which is provided a pump` 14 connects with the bottom of the fractionating tower for returning the recycle stock together with fresh oil to the tube bank 3 of the vaporizer 2, thus providing for continuous operation. The fresh charging stock is obtained from a tank 15 from which leads aV pipe line 16 to the cooler 1, the line 16 being provided with a. pump for forcing the charging stock at a desired rate of flow throughthe cooler 1. Usually this rate of flow is lin excess of the actual fuel requirements of the system since in order to reduce the temperature of the converter vapors abruptly it is necessary to use a relatively large quantity of cold liquid oil, and this quantity materially exceeds that which is necessary to maintain a constant amount of oilunder yheat treatment in the system. Therefore, the base of the fractionattower 10 is connected with a return pipe line 17 which leads back to the stock tank 15 so that by this means a substantially constant liquid level may be maintained in the bottom of the fractionating column.

The present invention refers more particularly, however, to the specific construction of the cooler 1 and associated apparatus. This cooler comprises a substantially cylindrical casing 18, provided with a. conical lower portion 19 and a. crowned 'upper portion 20',A

Within said casing to one side thereof there is situated a fixed baille wall 22 which extends from the crown of the casing to very nearly the conical wall or portion 19 of the casing, the said baille wall thus serving to separate thecasing internally into a cooling chamber 23 of relatively restricted proportions and a cate with the pipe line 16 leading from the n charging stock tank 15 to the cooler. It will be seen that the heated oil vapors and the finely divided liquid oil issuing from the jets 27 come into intimate contact while traveling through the cooling chamber 23, and due to the fact that the liquids and vapors are traveling at relatively high velocity and to the dispersion thereof and temperature differentials, an abrupt drop in the temperature of the oil vapors takes pla-ce.' Tests have disclosed that in less than one-fifth part of a second the vapors drop in temperature from approximately 1000O F. to 600 F.

The oils which remain in vaporous form following this drop in temperature arise in the enlarged vapor chamber 24 where they are permitted to expand and to travel at relatively low velocity as compared with their rate of travel through the conduit 26 and the cooling chamber 23. It will be understood ythat in a system of this kind a certain small amount of carbon is formed or liberated. This may be due to the time required in dropping the temperature of the oil vapors from 1000o F. to less than 600 F. I believe, however, that it is due in part at least to the fact that the charging stock introduced into the vapors is heated so rapidly that it is evaporated to a point of dryness, and this is apt to leave a trace of carbon deposit. Due to the provision of the enlarged vapor chamber and the relatively reduced rate of flow of the vapors therethrough into the line leading to the fractionating column, any free carbon present. in the cooler is dropped into the bottom 19 thereof, and is not carried by entrainment with the vaporsvinto the fractionating column and then through other associated apparatus. Again, the cooler herein described eliminates the employment of jackstones or other analo gous obstructions in the oil and vapor l1ne thereof, as described in the aforesaid patent to Weaver. Due to the removal of all such obstructions-the cooler is maintained in an open condition at all times so that dangerous pressures cannot be built up therein.

The liquid oil which accumulates in the bottom of the cooler passes by way of the pipe line 12 to the bottom of the .fractionating tower. In this pipe line I place a pump 28 and afpair of alternately used filters 29. These filters may each comprise a casing, consisting vof a bed of fullers earth. The oil is forced therein, the other filter may be in operation so that the sustained operation of the system will not be interrupted.

In view of the foregoing it will be seen that the present invention provides a cooler for use in vapor phase systems of oil conversion characterized by its simple, mechanically durable and operatively efficient design. `The restricted cooling chamber provides for effective heat transfer between the converter vapors and the liquid oil of the charging stock,

ybrin,f 1;ing about the desired substantially instantaneous drop in the temperature of the converter vapors. It will be observed that the cooling chamber 23 is open and unobstructed so that the vapors and liquid oil may pass therethrough athighivelocity. The lighter fractions ofthe liquid oilmay be vaporized by the heat exchange thus effected. These vapors may pass oft to the fractionating tower together with the vapors resultingfrom the conversion operation. Due 'to the size of the enlarged vapor chamber 24 the entrainment of carbon in said vapors flowing to the fractionating tower is rendered negligible without the use of a screen or other lter in the vapor outlet of the cooler. The liquids which accumulate in the bottom of the cooler and which contain to some extent coke or free carbon are filtered so that when such liquid y oils enter the -fractionating tower, or other tank, they are substantially free from coke or free carbon.

What is claimed is:

l. In an oil treating system, a cooler formed to include a casing provided with communicating internal cooling and vapor chambers. means for introducing heated oil vapor and nely divided liquid oil into said cooling chaniber for intimate heat exchanging admiXt-ure, said cooling and vapor chambers being in open communication with each other contiguous to the lower portions thereof, a vapor outlet leading from the upper end of said vapor chamber, a liquid outlet leading from the lower portion of said vapor chamber, a fractionating tower. a pipe line between said vapor outlet and said fractionating tower, a pipe line between said liquid outlet and the lower portion of said fractionating tower, and a carbon removing lter in the pipe line leading froml said liquid outlet to said fractionating tower.

2. In an oil treating system, a cooler comprising'a casing structure formed to include spaced inlet and outlet chambers, said chambers being in relative communication adjacent to their lower ends, the inlet chamber being of restricted cross-sectional area as compared with said outlet chamber, means for passing commingled highly heated oil vapors and a cooling liquid at high velocity through said inlet chamber to effect a sudden reduction in the temperature of the oil vapors, means for withdrawing liquids from the lower portion of the casing structure below said chambers together with solids formed asa result of said cooling operation, a fractionating tower, a vapor line leading from the upper portion of said outlet chamber to said fractionating tower, and meansfor passing the liquids withdrawn from the bottom of said cooler to said fractionating tower below the tower.

3. In an oil treating system, .a cooler formed to comprise a casing structure having provided therein spaced inlet and outlet chambers, the outlet chamber being of materially greater cross-sectional area than said inlet chamber, meansfor introducing highly heated oil vapors into the top of said inlet chamber, cooperative means for introducing a finely divided cooling liquid simultaneously introduced into the inlet chamber, whereby said mixture of vapors and liquid pass at high velocity downwardly through said inlet chamber to effect a sharp cooling in the temperature of said vapors, the cooled vapors passing upwardlyA at low velocity through said'outlet chamber, a fractionating tower into which the vapors released from `the top of said outlet chamber are delivered, a liquid line extending from the bottom of 4. In an oil converting system, a. converter,

means for passing oils through said converter and heating the same'to convertingl and vaporizing temperatures, a cooler situated convapor inlet of the l tiguous tothe vapor outlet of said converter u y "md .COmPlSm spaced inlet and outlet chambers, means for introducing vapors discharged from s( id converter into the top of said inlet chamber, means for introducing liquid oil in a finely divided form into the top of said inlet chamber for admixture with the vapors discharged from said converter whereby to efi'ect a sharp drop in the temperature of said vapors, a ractionating tower, means for passing vapors from the out-let chamber of said cooler into said fractionating tower, a liquid line extending from the bottom of said cooler to said fractionating tower, a filter disposed in said liquid line for'removing solids contained in the liquid upon the discharge of the latter from said cooler, a liquid line extending from said fractionating tower to the oil inlet side of said converter, and means for withdrawing vapors from the top of the fractionating tower.

5. In an oil treating system, a cooler formed to. include a casing provided with a vertically elongated cooling chamber of restricted cross sectional area and a parallel outlet chamber of materially greater cross sectional area, said chambers being in relative communication adjacent to the lower end of the casing, means for introducing highly heated oil Vapor which liberates solids during cooling into said cooling chamber, cooperative means for simultaneously introducing a finely divided liquid into the upper part of said cooling chamber for intimate admixture with said vapors, the restricted cooling chamber providing for a higher velocity of fluid travel therethrough than that which obtains in the larger outlet chamber, whereby to effect rapid cooling of the vapor in the cooling ch amber and the rejection of liberted solids from the yfluids passing through the n outlet chamber which were produced during the cooling of the vapors, aI ractionating tower, a vapor line for transmitting vapors from the upper portion of said outlet chamber to said fractionating tower, and a liquid outlet line leading from the lower portion of the cooler casing to said fractionating tower and entering the latter below the vapor entrance.

6. In anoil treating system, av cooler formed to include a casing provided with a l vertically elongated cooling chamber of restricted cross sectional area and a parallel outlet chamber of materially greater cross sectional area, said chambers being in relative communication adjacent to the lower end of the casing, means for introducing highly heated oil vapor which liberates solids dur ing cooling into said cooling chamber, co-

operative means for simultaneously introducing a finely divided liquid into the upper part of said cooling chamber for intimate admiXture with said vapors, the restricted cooling chamber providing for a higher velocity to fluid travel therethrough than that which obtains in the larger outlet chamber, whereby to effect rapid cooling of the vapors in the cooling chamber and the rejection of liberated solids from the fluids passing through the outlet chamber which were produced durcooler casing to said fractionating tower and entering the latter below the vapor entrance, and a pressure filtering means arranged in the liquid outlet line between said cooler and ractionatinof tower and operative to remove solids from tie liquids before the latter enter the fractionating tower.

7. In an oil treating system, a converter for cracking loils in the vapor phase, a cooler arranged to receive the highly heated vapors discharged from the converter, means cooperative with said cooler or introducing a relatively cool liquid into intimate contact with the vapors to sharply reduce the temperature of the latter, a fractionating tower, a vapor line for conducting vapors discharged from said cooler to said fractionating tower, a liquid line for conducting liquids discharged from said cooler to said fractionating tower, and pressure filtering means arranged in said liquid line to remove solids from liquids passing through said line ina confined flow stream prior to the introduction of such liquids into the fractionating tower.

In testimony whereof I afiix my signature.

CARY R. WAGNER.

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