US2690057A - Process and apparatus for cooling particle form solid contact material - Google Patents

Description

P 28, 1954 s. c. EASTWOOD 2,690,057

PROCESS AND APPARATUS FOR COOLING PARTICLE FORM SOLID CONTACT MATERIAL Filed April 5, 1950 4 Sheets-Sheet l '0 57/16 K 01? ECONOM/ZEI? INVENTOR. J'glvqnder Kids/Maud EASTWOOD FORM SOLID CONTACT MATERIAL 4 Sheets-Sheet INVENTOR. J'ylvam/er 6 [as/Mada! AGENT 0/? 17/ TUE/V5 7 Sept. 28, 1954 PROCESS AND APPARATUS FOR COOLING PARTICLE Filed April 5, 1950 u w a Sept. 28, 1954 Filed April 5, 1950 S. C. EASTWOOD PROCESS AND APPARATUS FOR COOLING PARTICLE FORM SOLID CONTACT MATERIAL 4 Sheets-Sheet 3 i l? i 52 KIL NI f L t I F i:

COULiER 1 INVENTOR.

gy/wander l? [ash/001i Sept. 28, 1954 s. c. EASTWOOD 2,690,057

PROCESS AND APPARATUS FOR COOLING PARTICLE FORM SOLID CONTACT MATERIAL Filed April 5, 1950 4 Sheets-Sheet 4 ?i E E 3;, INVENTOR. Jy/mnder K [as/mood MJW Patented Sept. 28, 1954 PROCESS AND APPARATUS FOR COOL- ING PARTICLE FORM SOLID CONTACT MATERIAL .Sylvander C. Eastwood, Woodbury, N. J assignor to Socony-Vacuum Oil Company, Incorporated, a corporation of New York Application April 5, 1950, Serial No. 154,130

Claims.

This application relates to the conversion of hydrocarbons in the presence of a comminuted solid contact material. It is particularly directed to the control of the temperature of, granular contact materials used in hydrocarbon converprocesses.

Various hydrocarbon conversion processes are known in which a hydrocarbon liquid or vapor is brought into contact with a comminuted solid material at a suitable, high temperature and for a suillcient period of time to provide a substantial conversion of the hydrocarbons into other more desirable hydrocarbons. In these conversion processes, a carbonaceous deposit is formed on the solid contact material impairing the function of the contact material, making it essential that the deposit be removed therefrom. It is customary in these processes to regenerate or restore. the contact material to its former condition by burning the carbonaceous deposit from the contact material.

In a preferred form of hydrocarbon conversion the solid contact material is continuously passed through a conversion zone as a substantially compact moving column of particle-form material. Hydrocarbons are admitted to the conversion zone and converted products removed therefrom continuously for long periods of time. The particle-form material is continuously withdrawn from the zone, contaminated with carbonaceous material. The contaminated material is then passed downwardly as a substantially compact column through a burning zone wherein the carbonaceous material is burned from the contact material, restoring the contact material substantially to its original state.

The burning of carbonaceous material on the solid contact material is highly exothermic. In many instances it is necessary to extract heat from the contact material before it can be transported through elevators which would be damaged by the excessive temperature of the material or before it can be supplied to the reaction vessel for further hydrocarbon conversion. The nature of the problems involved and the manner in which they are met by the present invention is well illustrated by apparatus for conversion of hi er boiling hydrocarbons to ethylene by reaction for a very short time, say 0.2 second at high temperatures on the order of 1500 F. and

above. To obtain the necessary short reaction time the high temperature reaction mixture must be promptly quenched to a low temperature. One advantageous system for accomplishing this high temperature short time reaction is to pass the charge hydrocarbons in direct contact with a bed of highly heated granular solid and then pass the hot reaction mixture through a bed of relatively cold granular solid. This requires two contacting chambers connected by a transfer line which will confine the hot gaseous mixture within a predetermined path. The hot contact material from the reaction chamber on which carbonaceous material is deposited during the conversion reaction is cooled from about 1000 to 1300 F. down to about 500 to 1000 F., lifted by a suitable elevator to a heater, in which the carbonaceous material is burned from the material, and then readmitted to the reaction chamber as a downwardly moving column of contact material. This problem is also illustrated by the adiabatic TCC process, in which solid contact material is passed downwardly as a substantially solid column through a reaction zone wherein it is contacted with hydrocarbons which are converted to suitable hydrocarbons in the gasoline range in substantial amounts and the contact material is then passed downwardly as a substantially solid column through a regeneration zone in which the contact material is contacted with a combustion supporting gas to burn off the carbonaceous deposits on the surface of the material. In the prior TCC processes, the regeneration, generally, provided suflicient heat to damage the catalyst, requiring the removal of heat from the kiln. This was accomplished by dividing the kiln into a series of burning and cooling zones. The temperature of the catalyst leaving each burning zone was controlled partly by the number of cooling coils in service in the following cooling zone. The cooling in the cooling zone was provided, generally, by one or more levels of horizontal, spaced tubes. Water was circulated through the number of tubes necessary to give the required cooling. Thus the effective heat transfer surface was varied by the number of tubes through which cooling water or steam was circulated. In normal cracking operations, the reactor conditions vary frequently, which, in turn, causes variations in the amount of heat generated in the kiln and, therefore, the amount of heat which must be removed in the cooling zones. This requires cutting water flow in and out of some of the tubes. Since a tube which does not have water flowing through it may be at a temperature of about ll;0.0 F., for example, while the water used for cooling may be only 200 to 400 F., severe stresses are set up in the tubes each time water is cut in or out. This caused frequent failure of the tubes,

particularly at the location where they are sealed into the header.

In the recent adiabatic process the catalyst flow rate is increased substantially, approximately 2 or 3 times the old rate. Consequently, the carbon laydown on the catalyst during reaction is reduced because the catalyst is retained in the reactor a shorter period. The maximum temperature reached in the regenerator, therefore, is maintained below the heat damaging level because there is a smaller per cent of carbon to be burned. The catalyst enters the kiln at approximately 850 F. and is withdrawn at some temperature below the heat damaging temperature limit. The heat damaging limit may vary depending upon the catalyst being of the order of 1200 F. for clay catalysts and 1400" F. for synthetic silicaalumina gel catalysts. No heat transfer tubes are needed in the kiln, permitting the kiln design to be exceedingly simple and easy to service. But, as previously indicated, generally, more heat is released in the kiln than is needed in the reactor, and, therefore, there is presented the problem of removing this excess heat from the sypstem. A catalyst cooler of some sort must be included in the system, usually located subsequent to the kiln.

Prior art catalyst or pebble coolers are not found satisfactory for a variety of reasons. Inasmuch as more or less heat must be extracted from the catalyst from time to time, some means of control of the cooler characteristics: is required. For example, many coolers allow the coolant to flow through exchanger tubes, being equipped with controls for preventing the fiow of coolant through selected tubes. The empty tubes assume the temperature of the moving contact material. Consequently, when they are put back in service, the cold coolant fluid contacts the hot walls of the tube, causing the metal to spall and crack. This necessitates frequent cooler repair and replacement. Many of the prior coolers are disfavored because of their complexity, excessive cost or difficulty of control. Because of their tendency to develop leaks, the use of cooling fluids under pressure was largely precluded in the prior art coolers.

The object of this invention is to provide a simple method of cooling and adjusting the temperature of hot granular contact material.

A further object of this invention is to provide a simple cooler for cooling and adjusting the temperature of hot, particle-form contact material.

Anotherobject of this invention is to provide an improved hydrocarbon conversion process.

Another object of this invention is to provide an improved process for the catalytic cracking of hydrocarbons,

These and other objects of this invention will be made apparent in the following discussion of the invention, read in conjunction with the attached sketches. The sketches are intended to illustrate the invention, and are highly diagrammatic in form.

The nature of this invention is best understood in connection with specific apparatus for practicing the specific processes noted above and such processes are described below in connection with the annexed drawings, all highly diagrammatic in form, in which Figure 1 is a diagrammatic showing of the relationship of the several elements making up a plant for the conversion of hydrocarbons toethylene; and in which Figure 2 is a detail view in section of the reactor outlet port of Figure l and the cooler located therebelow; and in which Figure 3 is a plant for conducting hydrocarbon conversion in accordance with adiabatic TCC principles; and in which Figure 4 is a view, partially in section, of the cooler used in the plant of Figure 3 and in which Figure 5 is a sectional view of an alternate embodiment of the invention.

Referring specifically now to Figure 1, a hot granular solid is heated to a suitable high temperature in heater It] and transferred by feed leg ll through a steam sealing zone IE to a reactor 13. A charge for the reaction is introduced by a plurality of inlet tubes M depending from ring manifolds l5 at the top of the reactor. Within the reactor 13 the charge is passed in direct contact with the highly heated granular solids and is thus rapidly coverted to a vapor phase mixture having the temperature desired for the reaction. Upon leaving the contact bed, the reaction mixture is quenched by the injection of water supplied from inlet I6 and is passed by conduit I! to a quencher l8 wherein it is passed through a moving bed of relatively cool granular solids for further reduction in temperature. The quenched reaction mixture is transferred by line E9 to a spray condenser 29 from which product vapors are taken overhead by line 2! to a suitable gas plant for purification and recovery of the gaseous products of the reaction. Oil and water from the bottom of condenser iii are passed to a settler 22 wherein they separate into an upper oil layer which is cooled in heat exchanger 23 before transfer to processing or storage and a lower water layer which is cooled in heat ezichanger 24 to be recycled in part to the spray condenser by line 25. If the charge to the reactor is in liquid phase, water from the bottom of settler 22 may be used in the charge since contamination of the charge water has no detrimental efiect in such operations, the contaminants being either vaporized with the water or deposited on the granular solid from which they may be removed by burning in the heater.

Returning now to the reactor 53, a purge gas such as steam is admitted to the bottom of the reactor at inlet 25 and a pressuring medium, which may also be steam, is admitted at inlet iii to be used to provide a pressure seal in the insulation of the vessel for preventing deposition of the carbonaceous substances in the reactor insulation. The granular solids are withdrawn from the bottom of reactor It by pipe 22 and are passed through a cooler 29 and depressuring pct 30 and then to the bottom of the elevator iii. In general, solids transferred to the elevator must be maintained at a temperature which will not damage the elevator or adversely affect its operation. The excess heat is extracted from the solids in the cooler 29. Solids are discharged from the top of elevator 38 into a feed pipe 32, passed through a classifier 33 for removal of particles broken down to a size smaller than that desired and are then fed to heater iii to again pass through the cycle. In the heater, fuel from inlet 34 is burned in preheated air supplied at 35 to generate a flame in direct contact with the solid granules and thus heat the latter to the desired degree. Flue gases are withdrawn at and passed to an economizer or stack.

The quencher is an element of a similar cycle of granular solids and wherein the granules serve to cool vaporous reaction mixture from reactor l3 and are then purged by steam admitted at 31 and passed by pipe 38 through the cooler 39 and depressuring pot 40 to an elevator 41. From the top of the elevator il the solids are discharged by pipe 42 through a classifier 43 to a hopper M. Solids are supplied through feed leg 45 to an air preheater t5 wherein they are contacted with air from blower il to preheat the same. The preheated air is then transferred by line -48 to inlet 35 of heater it.

Referring now to Figure 2, the internal structure of the coolers 29 and 39 is shown. The outlet of the reactor projects through the top of the cooler 29. In the lower section of the cooler is located a system of headers and connecting pipes 5i, horizontally disposed across the vessel. Cooling fluid is introduced through the headers and circulated through the pipes, all the pipes being maintained in a flooded condition. Contact material is discharged from th conduit 28 onto a horizontally disposed plate 52. A multiplicity of depending conduits 53 are substantially equally distributed across the plate, adapted to feed the contact material into the lower section of the cooler. Each depending conduit has a telescoping conduit 5 adapted to slip over the depending conduit to effectively increase or decrease the length of the conduit. The movable conduits 5 5 have lugs 55 attached to their outside wall to permit the attachment of cables 56. The cables 55 are attached to the wheel-s El. The wheels 57 are mounted on the horizontally disposed shafts 58, and rotate with the shafts. The shafts 58 are rotated, when desired, by operation of the motor 59, which drives through the reduction gear box 80.

Control of the contact material temperature is obtained, therefore, by controlling the position of the extension conduits 54. When less cooling is required, the conduits 5d are lowered, and the level of the compacted column of solid contact material in the cooling section of the cooler is lowered thereby, exposing one or more levels of horizontal cooling coils. Thus, a smaller volume of contact material is brought into contact with the cooling surface and, therefore, less heat is extracted from the contact material. When it is desired to extract more heat from the contact material, the extension conduits 54 are raised, which in turn raises the level of the contact material column in the heat exchanger section of the cooler. placing a larger volume of contact material in contact with the cooling surface.

It is seen thata ready means of adjusting the temperature of the contact material, while maintaining the heat exchanger flooded with coolant fluid is provided. Besides obviating the difficulties of former coolers, this cooler is simple and inexpensive to build and operate.

Referring now to Figure 3, a system is shown for carrying out adiabatic regeneration in a TCC process. A downwardly moving compacted column of catalyst particles .in the reactor is contacted with the hydrocarbon charge admitted through the conduit 1 I from .a stock preparation zone, not shown. The charge admitted may be in the form of a liquid, vapor or mixture of liquid and vapor, and the hydrocarbons may be admitted for concurrent or countercurrent flow with respect to the catalyst flow. The products produced by the catalytic conversion of the hydrocarbon charge are removed through the conduit T2 to other apparatus, not shown, for further treatment. .The fouled contact material is removed from the "bottom of the reactor 1E) 6 through the conduit 13 to the mixer 14. Lift gases are introduced into the mixer 14 through the conduits l5, l6, lifting the catalyst upwardly through the lift 11 to the separator it. The catalyst is separated from the gases and discharged through the conduit l9 into the regenerator 3d. The gases are discharged from the separator 38 through the conduit 8|. The regenerator 38 is a single zone kiln of relatively simple construction, and possessing no cooling coils. The catalyst is gravitated downwardly through the kiln and contacted with combustion supporting gas admitted to the kiln through the conduit 82. The flue gases formed by the combustion of the carbonaceous deposits on the catalyst are withdrawn from the regenerator through the conduit 33. Purge or inert gases are introduced into the system at appropriate points to prevent the reactant and converted vapors from mixing with the combustion supporting gas and vice versa. This is old in the art and not shown on Figure 3.

The regenerated catalyst is withdrawn from the bottom of the kiln 89 into the top section of the cooler 85. The cooler will be described in greater detail subsequently. The cooled catalyst is withdrawn from the bottom of the cooler through the conduit and introduced into a second mixer 88. The regenerated catalyst is lifted through a second lift 81 to a second separator 88. The catalyst is then discharged through the conduit 89 into the top of the reactor id, thereby completing the closed, continuous path.

The catalyst withdrawn from the regenerator in a dehydrated state, is lifted through the lift by means of air of flue gas to the separator 38 which also serves as a storage hopper. Steam is admitted to the hopper 88 through the conduit as. The flow is controlled by the valve. The steam enters the bed of material in the hopper through connecting pipes designed with a multiplicity of orifices for distributing the steam uniformly throughout the mass. The catalyst is hydrated upon contact with the steam releasing, in many instances, a large amount of heat. This heat release, for certain natural or treated clay catalysts may be as much as the heat of reaction of the hydrocarbons. In other instances, for example, when using various synthetic materials as catalyst, the heat release may be much less. The catalyst is withdrawn from the hopper, therefore, with a higher temperature than it possesses at introduction.

The catalyst is withdrawn from the kiln at a temperature of about 1200 F. and cooled in the cooler. The amount of heat extracted in the cooler is limited such that when the heat of hydration is added to the catalyst in the hopper above reactor, the catalyst will supply to the reaction zone at least a substantial amount of heat needed in the reaction zone. This heat requirement may include the heat of the conversion reaction and the sensible and latent heat required to bring the hydrocarbon charge up to reaction temperature and condition. For example, with a mixed liquid and vapor charge, the charge may be introduced into the reactor at say 700 F. and the catalyst at 1050 F. The average reactor temperature may be 925 F., with catalyst and converted products being withdrawn from the reaction zone at 875 F. The space velocity used in this process may vary from about 0.5 to 20 volumes of oil (at 60 F.) per hour per volume of catalyst in the reaction zone, and the catalyst to oil ratio may vary from about 1 to 10 volumes of catalyst introduced into the reaction zone per volume of oil (at 60 F.) introduced.

The catalyst circulation rate is maintained fast enouugh to prevent heavy depositions of coke on the catalyst to permit regeneration in one zone. In some instances, however, it may be desirable to use two or more zones with a cooling zone, as herein disclosed, between each burning zone. Or, in some instances, it may be expedient to use cooling coils within the kiln. But, the preferred form is as herein disclosed; the cooling zone located apart from the burning zone in the form of a separate cooler.

Referring now to Figure 4., the lower section of the kiln 80 is shown, wherein the catalyst discharges directly into the upper section of the cooler 84. The cooler 84 may have a circular or rectangular cross-section, although other shapes may be used successfully. The plate 5553 is horizontally disposed across the cooler and the conduits 9! depend from the plate at locations equally distributed across the plate. Surrounding each depending conduit 9| is a closely fitting conduit 92 adapted for rotation about the inner conduit. The outer conduit 92 is supported on the fiange 93 attached to the lower end of the inner conduit SI. The inner conduit is closed at the bottom by the flanged end 93 and has a series of orifices in its side wall located at equally spaced intervals along the length, each one being indexed an equal amount from the one located directly above. The outer conduit 82 has orifices similarly located with the exception that they are not indexed, being located one above the other. It is possible, therefore, by rotating the outer conduit to align any pair of orifices in the two conduits at any desired level. The catalyst flows into the inner conduit from the upper section of the cooler and out through the orifices placed in juxtaposition, forming a column of catalyst in the lower section of the cooler. The height of the column is seen to be controlled by the selection of the position of the outer conduit that brings the orifices in the conduits into alignment at the desired level. The catalyst gravitates by the cooling pipes 94 through which a cooling fluid is circulated. Therefore, the volume of catalyst placed in contact with the cooling surface is controlled by controlling the height of the column of catalyst in the cooler.

The shaft s5 is mounted in suitable bearing and rotated through rotation of the chain-driven wheel 98 and chain 99. The shaft IE is supported in upper and lower bearings IllI, I02. The lower bearings are supported by the crosssupport N33. The mating bevel gears I04, I rotate the shafts in, causing the rotation of the mating helical gears H38, 18?. By this pro cedure all the outer conduits 92 are indexed the same amount by the operation of the single element, the chain 99, thereby permitting easy adjustment of the height of the compacted column in the cooler.

The heat exchanger is kept flooded with coolant at all times, thus obviating many of the difiiculties of prior art coolers. There is no danger of the pipes cracking at the point of attachment to the headers, and hence, high pressure fluids can be used safely in the pipes. This is advantageous when water is used as the coolant. By controlling the pressure at a fixed value, for example 350 pounds per square inch, the temperature of the coolant is maintained at the boiling point at that pressure, and high pressure steam is produced for use in many places in the refinery operations. Other coolants than water may be used safely, such as salts in fused form, mixtures of potassium nitrate or nitrite, molten alloys and steam, for example, but water is preferred.

Referring now to Figure 5, another embodiment of the invention is shown, indicating that the invention is applicable to lateral movement of the catalyst across the tubes. Catalyst from a kiln is introduced into the top of the vessel I through the conduit I06. The conduit 1% is rectangular in cross-section, and has a slot in the lower section of one side. This may be covered by the cover IO'I, adapted to slide up and down in the grooves I08. By raising or lowerirrg the cover I01, the level of the catalyst in the vessel can be controlled. Cooling fiuid is introduced into the lower header I09 through the conduit H0, flows upwardly through the tubes III to the upper header H2, and is discharged through the conduit II3. The cooled catalyst is discharged from the vessel through the outlet conduit H4 located in the bottom thereof. The cover I6! is manually adjusted by the line H5 which passes over the pulley wheel IIE to give the desired amount of cooling of the catalyst. The tubes III are maintained flooded with the coolant fluid, obviating many of the difiiculties of prior coolers.

The drawings used to illustrate this invention are highly diagrammatic in form and are not intended to limit the invention to these embodiments shown.

One of the broad aspects of this invention relates to apparatus for and a method of cooling hot, granular contact material by gravitating the contact material through the cooling zone as a compacted column in contact with a cooling surface, maintaining the cooling surface in contact with a cooling fluid throughout its entire area, said cooling fluid being in indirect heat exchange relationship with the contact material, discharging the contact material from the cooling zone and adjusting the temperature of the contact material discharged by varying the volume of the contact material in the cooling zone in contact with the cooling surface. The volume of contact material in contact with the cooling surface is varied by changing the height of the column of contact material in the cooling region.

A method of operation related to that disclosed herein is disclosed in copending application Serial No. 148,669, filed March 9, 1950, which differs in several important respects from that disclosed herein.

What is claimed is:

1. The method of cooling 2, particle-form solid contact material which comprises feeding the contact material downwardly into a cooling zone as at least one confined stream, discharging at least a portion of the confined stream at a location to establish there the level of a gravitating column of contact material, gravitating the contact material through the zone as a compacted column in contact with a cooling surface, passing cooling fluid through confined paths in the cooling zone to form the cooling surface, maintaining the cooling surface in contact with the cooling fluid throughout its entire area, said cooling fluid being in indirect heat exchange relationship with the contact material, discharging the contact material from the cooling zone and controlling the temperature of the contact material discharged by varying in a vertical direction the locationat which the controlling portion of the confined stream is discharged, intermediate the top and bottom of said cooling surface.

2. The method of cooling a particle-form solid contact material which comprises feeding the contact material downwardly into a cooling zone through a multiplicity of confined zones projected into the cooling zone, said confined zones each having a cross-section substantially smaller than the cooling zone and being substantially equally distributed across said zone, discharging the contact material from the confined zones into the cooling zone at a substantially uniform vertical location to form there the free surface of a descending column of contact material, passing a multiplicity of confined streams of cooling fluid through said cooling zone to effect an indirect heat exchange with the gravitating contact material, withdrawing the contact material from the bottom of said cooling zone and adjusting the temperature of the contact material discharged by varying the elevation at which the contact material is discharged from the confined zones intermediate the top and bottom of said cooling zone to control thereby the volume of contact material in indirect heat exchange contact with the confined streams of cooling fluid.

3. A cooler for granular contact material comprising an enclosed vessel, means for feeding contact material into the top of said vessel, a horizontally disposed plate in the upper portion of said vessel dividing the vessel into an upper storage chamber and a lowercooling -cham ber, a vertically disposed heat exchanger located in the lower cooling chamber, a multiplicity of depending conduits attached to said plate equally distributed across said plate adapted to feed contact material from said storage chamher into said cooling chamber, a multiplicity of conduits telescoping said depending conduits, said conduits adapted to be lowered into the interstices of the heat exchanger to maintain at the outlet of said conduits a gravitating, substantially solid column of contact material, means defining an outlet in the bottom of said vessel for withdrawing contact material from said vessel, and means for raising and lowering the telescoping conduits to control the temperature of the contact material discharged from said vessel.

4. A cooler for particle-form solid contact material comprising an enclosed vessel, means for feeding contact material into the top of said vessel, a horizontally disposed plate in the upper portion of said vessel dividing the vessel into an upper storage chamber and a lower cooling chamber, a vertically disposed heat exchanger located in the lower cooling chamber, a multiplicity of depending conduits attached to said plate equally distributed across said plate, said conduits being closed at the bottom and defining a series of orifice openings through the side wall at various levels, said conduits adapted to feed contact material from the storage chamber through the orifice opening to the cooling chamher, a multiplicity of outer conduits surrounding said depending conduits of substantially the same length and similarly closed at the bottom, said outer conduits also defining orifice openings at substantially the same level as the orifices of the inner conduits, the orifices of the inner and outer conduits so located that rotation of the outer conduit brings into juxtaposition the orifices of the inner and outer conduits at each selected level separately, said conduits projected into the interstices of the heat exchanger, means defining an outlet in the bottom of said vessel for withdrawing contact ma terial from the vessel, and means for rotating said outer conduits to adjust the tensperature of the contact material discharged from said vessel.

5. A cooler for particle-form solid contact material comprising an enclosed vessel, said vessel. having a downwardly and laterally directed floor, the angle of said floor being greater than the angle of repose of the contact material, a vertically disposed heat exchanger located in said vessel, a feed conduit projected into the top of said vessel adapted to feed contact material into said vessel to maintain a laterally gravitating column of contact material in contact with the lower portion of said heat exchanger, outlet means for withdrawing contact material from the bottom of said vessel, and means associated with said feed conduit for varying the vertical location of the free surface of the laterally gravitating contact material to control the temperature of the contact material discharged from the cooler.

6. The method of changing the temperature of a particle-form contact material which comprises passing the particle-form contact material downwardly as a substantially compacted mass through a heat exchange zone having a predetermined maximum heat transfer area available for contact with the compacted mass of contact material moving therethrough, directing the fiow of contact material in the heat exchange zone into contact with only the lower portion of said maximum heat transfer area up to an adjustable level, efiecting intermediate the top and bottom of said heat transfer area, variation of the level of the substantially compacted mass in contact with the heat transfer area as required to maintain the desired contact material exit temperature from said heat exchange zone.

7. The method of cooling a particle-form solid contact material which comprises: passing a cooling fluid in indirect heat transfer relationship with but out of communication with at least a portion of at least one flow space available for contact material fiow in a cooling zone so as to provide predetermined maximum cooling heat transfer area which could be contacted by contact material when fiowing in compacted condition through said fiow space, discharging at least one gravitating laterally-confined stream of contact material into said flow space to form therebelow a gravitating substantially compact bed of thecontact material in contact with at least a portion of the cooling heat transfer area, intermediate the top and bottom of said heat transfer area, discharging cooled contact material from the lower section of said fiow space and effecting variation of the level at which contact material is discharged into said flow space to adjust the level of the bed in contact with the cooling heat transfer area so that the contact material contacts that portion of the heat transfer surface required to maintain the desired contact material discharge temperature.

8. The method of cooling a particle-form solid contact material which comprises: passing a multiplicity of confined streams of cooling fiuid through a cooling zone to provide a predetermined maximum cooling surface area for indirect heat exchange contact with gravitating hot solid contact material, feeding the contact material downwardly into the cooling zone through a multiplicity of laterally confined paths downwardly projected into the zone, said laterally confined paths each having a cross-section substantially smaller than the cooling zone and being substantially equally distributed across the zone, discharging the contact material from the laterally confined paths into the cooling zone at a substantially uniform vertical location to form there the free surface of a gravitating substantially compact bed of the contact material which contacts the cooling surface area up to that level, intermediate the top and bottom of said cooling surface area, withdrawing the contact material from the bottom of said cooling zone, and varying the elevation at which the contact material is discharged from the laterally confined paths to place that volume of contact material in indirect heat exchange contact with cooling surface required for producing the desired temperature of the contact material withdrawn from the cooling zone.

9. A cooler for comminuted solid contact material comprising an enclosed vessel, heat exchanging means in the lower portion of the vessel, said means providing a predetermined cooling surface area available for contact with hot contact material, conduit means adapted for transfer of contact material from the upper portion of the cooler downwardly out of contact with the cooling surface to a discharge level located intermediate the top and bottom of the heat exchanging means, means defining an out let in the bottom of the cooler for withdrawal of contact material, and means associated with said conduit means adapted to permit variation of the level at which contact material is discharged,

whereby the volume of contact material in contact with the cooling surface is adjusted to that required for the desired temperature adjustment.

10. Apparatus for adjusting the temperature of a granular contact material comprising in combination: an enclosed vessel, heat exchanging means in the lower portion of the vessel, said means providing a predetermined maximum heat transfer surface area available for contact with the contact material, conduit means projected downwardly in said apparatus and terminating at a level intermediate the top and bottom of the heat exchanging means, said conduit means adapted for transfer therethrough of contact material in the form of a substantially compact bed and the formation of a substantially compact bed of contact material in said vessel up to the level at which said conduit means terminates, means for varying the length of said conduit means to place the contact material in contact with sufficient heat transfer surface area to provide the desired temperature adjustment and means defining an outlet in the bottom of said vessel through which the temperature adjusted contact material is withdrawn in the form of a substantially compact column.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,803,081 Uhle et al. Apr. 28, 1931 2,379,195 Simpson et al June 26, 1945 2,452,172 Willard Oct. 26, 1948 2,477,502 Utterback et al July 26, 1949 2,506,545 Crowley May 2, 1950 2,573,795 Lanning Nov. 6, 1951

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