US1992307A - Temperature exchange between a catalytic mass in the course of regeneration and a cooling liquid - Google Patents

Description

E. HOUDRY IQUID TEMPERATURE EXCHANGE BETWEEN A CATALYTIC MASS IN T H COURSE OF REGENERATION AND A COOLING L Filed Jan. 27, 1932 Feb. 26, 1935.

I JHINVENTOR 06% g BY f ATTORNEY Patented Feb, 26, 1935 UNITED STATES PATENT OFFICE 1,992,307 I TEMPERATURE EXCHANGE BETWEEN. a

CATALYTIC MASS IN THE COURSE OF REGENERATION AND A COOLING. LIQUID Eugene Houdry, Paris, France, assignor to Houdry Process Corporation, Dover, DeL, a corporation of Delaware Application January 2'1,

In France February 21, 1931 8 Claims.

. This invention relates to ways and means for controlling the temperature of a catalytic mass during regeneration in the conversion and treatment of hydrocarbons.

Disclosures have been made in' United States pending application Serial No. 440,199 /2' of Alfred scribe arangements for the treatment of gas or of mixtures of gas or of vapors in the presence of catalytic and refining agents, and -for the reactivation of these agents. In the aforesaid United States application Serial No. 440,199 /2, there has been described a form of construction which is characterized by the disposition, within the catalytic or refining mass, of a pipe system (bank or coil) forthe circulation of a cooling medium, the purpose of this medium being to hinder excessive rise in temperature during the period of regeneration of the catalytic or reflning mass from the combustion of the material deposited therein, which must be eliminated in order to reactivate the catalytic or refining mass.

It has been discovered that, in order to obtain practical results on a commerical scale by this process of cooling, which operates within the mass during the periods of regeneration, it is indispensable that a systematic exchange of calories be effected between the cooling medium and the mass to be cooled. This systematic interchange is practically impossible of realization if a gaseous fluid is employed as the cooling medium. Indeed, such a fluid is heated progressively in the measure that it circulates in the pipe stack of the ,exchangen-with the result that the walls of the latter in the end are found to be at temperatures quite variable between the point of admission of the fluid into the apparatus and the point of exit from the latter. In order to accomplish, between the gaseous fluid and the mass, through the'wall of the exchanger, an in-- 1932, Serial No. 589,134

cordance with previous usage, namely, with the pipes constantly full of liquid.

The present invention has for its object process and apparatus which can be employed in a manner particularly advantageous in combination with constructions such as described and shown in the aforesaid United States patent applications and which overcome entirely the defects and disadvantages referred to above.

The operation conforms to the invention, which permits in known'manner the use of a .heat exchanger formed by a pipe bank (in serpentine coil or otherwise), wherein circulates a liquid such, for example, as water, the stack traversing the catalytic or refining mass to be regenerated. It is characterized in that the sections in the pipe bank and the outlet for the cooling liquid are proportioned and arranged'in such a manner that they insure, throughout the length stantly the temperature of ebullition corresponding to the. circulation pressure.

From this fact, it follows that the temperature of thewall of the exchangeris itself maintained substantially constant throughout the extent of the bank. Each element of the bank, always maintained charged with liquid up to a predetermined level which permits vaporization, functions, so to smak, as a boiler tube producing steam at constant temperature.

,With the methods employed up to this time for the circulation of a gaseous-fluid or of a liquid, the cooling agent, at the expense of the surrounding temperature, was suflicient without giving any concern to the maintenance of a uni- 7 fect such umformity. The new procedure solves a new problem in the particular arrangement disclosed herein, and it solves it by the indicated means, namely, by a pipe bank maintained constantly charged with liquid up to a conveniently determined level. In conformity with the new arrangement, the evacuated liquid, which is under control at its exit from the exchanger, is brought back to the feeding manifold, the delivery of cooling water to the exchanger being maintained constant by the addition of water corresponding to the quantity which has been transformed into steam in the course of the admission and evacuation cycle. 7

One form of realization of an apparatus for the application of the new-principle'is represented in the annexed drawing, applied, by way of example, in combination with an apparatus element conforming to those described and shown in the aforesaid copending United States application Serial Nos. 505,140 and 516,159.

Fig. 1 shows such an element in side elevation, but partly cut away to show a portion in central vertical section.

Fig. 2 is a transverse sectional view substantially on the line 22 of Fig. l.

The disclosed apparatus comprises a continuous chamber a-b with vaporization efiected in the upper portion or chamber a, catalytic crackingtaking place in the chamber b immediately therebelow in such a way that the products, whatever their degree of vaporization, pass directly by gravity from the evaporator a into the cracking chamber 1) without any dephlegmation, and without the need of submitting them to any intermediate reheating. The contact material a may comprise any inert porous material in lump form such as pumice stone, broken brick, or molded pieces of the porous carrier disclosed and claimed in United States Patent No. 1,818,403, issued August 11, 1931 to Alfred Joseph. The catalyst 17 is of any suitable material for effecting the desired conversion such as broken fragments of metal, such as iron and nickel, or metallic oxides, preferably in or on a carrier such as that disclosed in the.aforesaid United States Patent No. 1,818,403, or activated clay with or without the addition of metal, metallic oxides, or other active or non-' active substances, in the form of pellets or molded pieces, as disclosed in my copending application, .Serial No. 600,581, filed March 23, 1932. The operating temperature will depend upon the extent and character of the conversion and upon the nature of the oil undergoing transformation, but will normally be in excess of 750 F. The regeneration of catalyst b with which the cracking chamber is charged, and the regeneration of the absorbent material a, with which the vaporizer is charged, can thus be effected simultaneously by the admission of air under pressure into the lower chamber b. As the drawing shows, there is provided, for this purpose, an admission pipe 11 from which the air is distributed by a series of conduits to all parts of mass 1), the waste air rising throughthe contact mass a to regenerate the latter.

Well within the mass 2) is disposed the heat exchanger, formed, by way of example, by a serpentine coil whose horizontal elements 1 to 10, inclusive, are connected together as shown in the drawing. In the coil during the periods of regeneration, there is caused to circulate a cool- 1 ing liquid, such, for example, as water, admitted into the branch or horizontal. element 1 by a conduit 0. From time to time, from points high in the connections between the horizontal elements of the coil, lead bent conduits d and d for the steam, which discharge into a collector 6, into the lower end of which extends element 10 of the coil. Below collector e is disposed a reservoir from which condensed water is drawn by pump g, which discharges it, by a conduit it, into the lowerend of the water feed line near the first horizontal element 1.

In accordance with the invention, the sections of the pipe elements 1 to 10, inclusive, and the rate of feed from conduit 0 are established so thatthroughout the length of horizontal elements 1 to 10, inclusive, there is continuously present liquid with a free level, as indicated in Fig. 2, in order to insure continuous vaporiza- The constant presence of water throughout the coil can be ,controlled, for example, by restriction at the lower end of collector e. As has been pointed out above, ,the supply of water from conduit 0 will be controlled in a manner to maintain a constant feed, the amount of feed water corresponding to the quantity of water vaporized during the course of the admission and evacuation cycle.

The steam carried away by the vent pipe e from the upper end of collector e can be utilized in various ways.

In order to show the economy of the above described proceeding, it can be illustrated by the following example: Apparatus-such as that represented, and of which the catalyzer or refractory material charge t6 be regenerated is about 900 liters, is disposed in a heater maintained at a temperature of 450 C. Then, if one is to accomplish regeneration on an industrial scale, it is necessary to effect, during the period of regeneration, a cooling such that the temperature in chambers aand b shall not exceed 550 C. or thereabouts. From the fact that a consant temperature fixed at 550 is to be maintained in the mass to be regenerated, the heater in which the elements a and b are disposed being maintained at 450 C., a constant exchange must be effected between the regenerating mass and the heater, through the metallic wall of element a-b, some 10,000 calories per hour. The charge of air is, in the example considered, about 84 cubic meters per hour, and thedquantity of carbon burned per hour amounts to 109% kilograms, which gives a time of regeneration, at most, equal to the duration of the working period. During the regeneration, there is circulated on the average 120 kilograms of water per hour, comprising 60 kilograms of water recovered at the discharge of the exchanger at a temperature of 100 C. and 60 kilograms of water admitted into the circulating coils. There is collected, at the vent or evacuation conduit e, 60 kilograms of steam per hour.

In summary, the described procedure permits not only the maintenance of a constant temperature at the walls of the exchanger elements 1 to 10, inclusive, but it effects, in comparison with apparatus disclosed in the aforesaid copending United States application Serial No. 516,159, with a systematic and regular exchange of calories, a

considerable economy in the amount of water consumed and an additional economy of calories in the form of the recovered water vapor or steam.

The invention claimed is:

1. In a process for converting heavier hydrocarbons into lighter hydrocarbons involving the use of a transforming catalytic mass requiring periodic regeneration by oxidizing the contaminating material taken' up during an operative run and the removal of a portion of the heat of regeneration, the process steps which comprise efiecting indirect heat exchange during regeneration of the mass between the mass and a cooling liquid at a plurality of substantially horizontal levels within and throughout the mass, and maintaining the liquid under pressure at each level while permitting vaporization of the liquid, thereby to insure heat absorption by said cooling liquid at a substantially constant and uniform temperature all through the mass.

2. In a process for converting heavier hydrocarbons into fighter hydrocarbons involving the use of a transforming catalytic mass requiring periodic regeneration by oxidizing the contaminating material taken up during an operative run and the removal of a portion of the heat of regeneration, the process steps which comprise eifecting indirect heat exchange during regeneration of the mass between the mass and a cooling liquid at a plurality of substantially horizontal levels within the mass, supplying the liquid at a predetermined rate while permitting vaporization of the same by the heat taken up from said mass, and venting the vapors so as to maintain the liquid under a predetermined pressure so that heat will be absorbed throughout the mass by the liquid at a substantially constant temperature, namely, the boiling temperature of the liquid under the predetermined pressure conditions.

3. In a process for converting heavier hydrocarbons into lighter hydrocarbons involving the use of a catalytic mass requiring periodic regeneration by oxidizing the contaminating material taken up during an operative run and having a pipe bank or coil embedded in said mass for the purpose of dissipating a portion of the heat of regeneration, the process steps which comprise circulating a cooling liquid through said coil, maintaining the liquid at all parts of said coil at a level permitting free vaporization,

progressively venting the liquid vapors to prevent interference with the movement of the liquid and to maintain a predetermined pressure in said coil, condensing a portion of said vapors, and recirculating the condensate along with fresh liquid.

4. Apparatus for the conversion of hydrocarbons comprising a chamber having a mass of catalytic material therein requiring periodic regeneration, means for supplying oxidizing material to said mass to effect regeneration of the same, heat removing means in the form of a heat exchange coil embedded in said mass and having a plurality of horizontal sections, means for feeding liquid to said coil, and means for progressively venting the vapors from said coil thereby to provide for liquid in all portions of the coil at levels permitting free vaporization.

5. Apparatus for the conversion of hydrocarbons comprising a chamber having a mass of catalytic material therein requiring periodic regeneration, means for supplying oxidizing material to said mass to eifect regeneration of the same, heat removing means in the form of a pipe bank or coil having vertically spaced horizontally extending sections, means for admitting cooling fiuid'to the upper portions of said coil, vents for certain of said sections of said coil for carrying away vapor of said liquid, means for condensing at least a portion of said vapor, and

means for discharging said condensate into the upper portions of said coil.

6. Apparatus for the conversion of hydrocarbons comprising a chamber having a mass of catalytic material therein requiring periodic regeneration, means for supplying oxidizing material to said mass to effect regeneration of the same, heat-removing means in the form of a pipebank or coil having vertically spaced horizontally extending sections, means for admitting cooling fluid to the upper portions of said coil, vents for certain of said sections of said coil for carrying away vapor of said liquid, a collector into which said vents discharge, the lowermost of said horizontal sections of said coil leading into said collector, said collector having an outlet at one end thereof for vapor, and means for recirculating the condensate from the other end of said collector through said coil.

7. Apparatus for the conversion of hydrocarbons comprising a chamber having a mass of catalytic material therein requiring periodic regeneration, means for supplying oxidizing material to said mass to effect regeneration of the same, heat removing means in the form of a pipe bank or coil having vertically spaced horizontally extending sections, means for admitting cooling fluid to the upper portions of said coil, vents for certain of said sections of said coil for carrying awayvapor of said liquid, a collector into which said vents discharge, the lowermost of said horizontal sections'of said coil leading into said collector, said collector having an outlet at one end thereof for vapor, a reservoir beneath said collector, a conduit of restricted size providing a gravity connection between said collector and said reservoir, and means for discharging into the liquid inlet to said coil the condensate which drains into said reservoir.

8. In apparatus for the conversion of hydrocarbons, a casing providing two connecting chambers in superposed relation, the upper or evaporating chamber having a mass of absorbent material therein, the lower or cracking chamber having a mass of adsorbent catalytic material therein, means in said lower chamber for distributing air or other oxidizing substance throughout said catalytic mass, heat removing means in the form of a pipe bank or coil having vertically spaced horizontally extending sections embedded in said catalytic mass, means for supplying cooling liquid to said coil so as to maintainthe liquid in said horizontal sections at levels permittng free vaporization thereby to establish during regeneration periods a temperature in all portions of said coil conforming to that of the boiling point of the liquid under the pressure conditions obtaining in said coil, means for condensing a portion of the vapor of the liquid and for recycling it through said coil, and means at the top of said upper casing for admitting the hydrocarbon during operating periods, and for venting theioxidizing substance and its products during the periods of regeneration when both masses are simultaneously freed of deposits from the previous working period.

EUGENE HOUDRY.

CERTIFICATE or CORRECTION.

Patent No. l, 992, 307. February 26, 1935.

It is hereby certified that the name of the patentee in the above numbered patent should have been written and printed as Eugene J. Houdry instead of Eugene Houdry; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case ,in the Patent Office.

Signed and sealed this 26th day of March, A. D. 1935.

Les l ie Frazer (Seal) Acting Commissioner of Patents.

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