US2507523A - Conversion of hydrocarbons - Google Patents

Description

May 16, 1950 E. J. HouDRY CONVERSION oF HYDRocARBoNs 2 Sheets-Sheet 1 Filed Aug. 51, 1946 IN V EN TOR. 17011097 `14] AVEK 2 Sheets-Sheet 2 E. J. HOUDRY CONVERSION 0F HYDROCARBONS 1N VEN TOR. l] we all/01109' BY May 16, 1950 Filed Aug. :51, 194e latented May 16, 1950 CONVERSION OF HYDROCARBONS Eugene J. Houdry, Ardmore, Pa., assignor to Houdry Process Corporation, Wilmington, Del., a

corporation of Delaware Application August 31, 1946, Serial No. 694,327

(Cl. 19E-49) 7 Claims.

This invention relates to treatment, conversion or transformation of hydrocarbons, particularly heavy hydrocarbons such as reduced crudes and tarry or asphaltic bottom or residual fractions of any type or source, and to production therefrom of valuable motor fuels, burning fuels, special chemical products, etc. In other Words. it proposes to use as its charging stock the materials in a renery which are the least valuable, the most troublesome to handle and to dispose of, and the most diiicult to process by reason of the fact that most of the undesirable difficultly vaporizable components of petroleum such as tar, asphalt or the like together with corrosive compounds from sulphur crude, etc. tend to concentrate in the heavier fractions. These residual hydrocarbon fractions crack readily but tend to go almost directly to gas and coke if the reaction temperature is too high or the contact mass too active and the liquids produced will still contain corrosive components.

One object of the invention is to process residual hydrocarbons so as to obtain a good yield of desirable light products therefrom. Another object is to handle corrosive as well as non-corrosive stocks. Another object is to produce high quality products. Other objects will be apparent from the detailed description which follows.

The invention involves treating the charging stock in a series of operations or zones. In the first zone a contact treatment with solid, substantially inert, heat resistant material is effected to vaporize, viscosity-break or vis-break, desalt and remove solid inorganic materials from the charging stock. To this zone the charge stock is fed preheated if necessary, together with hot vapors from any suitable source but preferably with hydrocarbon vapors from a cracking operation. The vaporized products from this rst zone, if from a sweet crude, are sent directly to a fractionating zone for separation into desired fractions for direct use or for further treatment. If the vaporized products from the vis-breaking and desalting zone are corrosive, as from sulphur crudos, they are given an intermediate treatment before fractionation by being sent directly to a selective cracking and desulphurizing zone. In the selective cracking zone the vaporized products from the rst zone are subjected under mild freckin'r conditions to the action of mild cracking catalysts to break down the sulphur and corrosive compounds with or Without desulphurizing agents or catalysts to extract and retain the sulphur.

The heavier fractions separated out in the `2 fractionating zone are good cracking stocks and may be charged to a conventional cracking zone of any desired type for further conversion as to gasoline or the like. When this is done the resulting vaporized cracked products may comprise in whole or in part the hot vapors to be mingled with the heavy fresh charge fed to the first zone.

In accordance with the invention, the aforesaid vaporizing and viscosity-breaking zone may comprise a, plurality of spaced contact masses formed from material which is substantially inert catalytically. The charge stock comprising heavy hydrocarbons of the character described, while at least partially in the liquid phase, is fed into the respective chambers dened by each set or pair of adjacent contact masses and, in each chamber, partial vaporization of such charge stock occurs, the remaining liquid phase portion of the charge stock passing into the succeeding contact mass where it is vaporized and viscositybroken.

Further in accordance with the invention, the aforesaid cracking zone may comprise a plurality of spaced contact masses formed at least to substantial extent from catalytic material. The heavier fractions from the fractionating zone may be charged through these contact masses in series and, simultaneously, hydrocarbon material adapted for cracking, while either in the gaseous phase, liquid phase, or both, is admitted to the respective chambers dened by each set or pair of adjacent contact masses last named.

Various other objects and advantages of my invention will become apparent from the following detailed description.

My invention resides in the art, process and system of treating hydrocarbons as hereinafter described and claimed.

This application is a continuation in part of my pendinT applications Serial No. 505,109, filed October 6, 1943, now abandoned, and Serial No. 574,731, iiled January 26, 1945, now abandoned.

For an understanding of my invention and for an illustration of some of the applications thereof, reference is to be had to the accompanying drawings, in which:

Figures v1 and 2 are diagrammatic views illustrating the process of my invention.

Referring to Fig. 1, heavy fresh charge, while at least partially in the liquid phase, is fed by line 2 into Zone A where low pressure conditions should prevail. Prior to the beginning of an on-stream period, the temperature of the contact material in zone A is elevated in suitable manner, as by a regenerating operation following a, previous on-stream period, into a range, for example, between 800 F. and 1250 F., which is effective as regards vaporization and viscositybreaking of the difflcultly vaporizable components of the heavy fresh charge. The upper lev^l of the aforesaid range should not exceed 1250 F., for example, so as to avoid, for a contact time, for example, not exceeding fifteen seconds, any substantial cracking of the heavy fresh charge into lower boiling hydrocarbons of the gasoline type, the contact time being the time required for passage through the contact material of those vapors which are introduced thereto or produced therein.

At the beginning of an on-stream period, heavy fresh charge, while at least partially in the liquid phase, is fed into zone A by line 2, Fig. 1. Hot vapors enter the zone A as the foregoing operation proceeds and, to this end, if desired but not necessarily, the hot vapors may be passed through line 3 and mingled with the heavy fresh charge before admission thereof to said zone A. If the heavy fresh charge is not free-flowing at room temperature, it should be heated at least to such extent that it is free-flowing so that it may readily be passed through the line 2. The temperature of the heavy fresh charge may be higher than as just stated, for example, as high as 850 P. or within a range such, for example, as from 200 F. to 800 F. The temperature of the hot vapors traversing the line 3 should be higher than that of the heavy fresh charge traversing the line 2 but the temperature and relative quantity of these hot vapors should not be enough to cause the mixture in the zone A, prior to engagement with the contact material, to have temperature higher than that of said contact maierial. In zone A, the mixture of vapors and heavy charge is subjected to reaction in the presence of the aforesaid solid contact material which is substantially inert catalytically, heat resistant and in pieces of substantially uniform surface area and volume, as in spheres or equivalent pieces having diameters in the range of 1A to of an inch for example, about half an inch. The contact material may be made up of any substances which have the requisite properties and are otherwise suitable, such as fused alumina, fused silica and alumina, heat resistant quartz and quartz pebbles, fused silica, etc. The size of the pieces of this contact mass bears a relation to the operating temperature in this zone; for example, the size just indicated is suitable for operations in a temperature range averaging 850 F. to 950 F. of the contact mass. For lower average temperature within the desired operating range, pieces of smaller size should be used so as to present more surface.

While the contact material in zone A is substantially inert it may have some slight catalytic effect. However, the cracking that takes place is mostly from the effect of heat. As stated, the purpose of this zone is to vaporize the heavy charging stock and such cracking as takes place is largely in the nature of splitting of the heavy molecules of the charge in what is essentially a vis-breaking operation. This vaporizing and viscosity-breaking operation is effected in response to transfer'to the heavy charging stock of heat from the contact material and, preferably, it is the heat which is stored in said contact material by a. previous regenerating operation that constitutes the sole source of heat for effecting said vaporizing and viscosity-breaking operation. Relatively high feed rates are maintained in this zone, as one volume (liquid basis) oi the feed (liquid basis) of mixture to one volume of con' tact material.

A substantial depth of contact material is maintained in zone A and the operation may be conducted with fixed bed or beds, with a moving bed, or in a process of the general fluid" type. With fixed and moving beds, an overall depth of from 8 to 12 feet of contact material is practical for the usual heavy stocks, as, for example, 9 feet of bed. If fixed bed reactors are used they may have, for example, a single contact section 9 foot in depth, 2 sections of 41/2 feet each, 3 sections of 3 feet each, or 4 sections of 21/2 feet each, etc. When sectional beds in a plurality of spaced contact masses are thus used, a portion of the fresh charge is fed between each pair of sections as, for example, after the manner disclosed in my aforesaid copending application Serial No. 505,109, filed October 6, 1943, now abandoned, relating to sectional converters. During the vaporizing and vis-breaking operation a layer of carbonaceous material accumulates in and on the contact mass along with non-volatile inorganic material which may be referred to as ash and/or salts. The burnable portions of the deposit are removed periodically by a regenerating operation in known manner. The contact material should also be freed of ash and deposited salts at intervals by a hot water or dilute acid wash. When a moving bed reactor is used in zone A the washing of the contact mass can be effected as a part of the regenerating operation. Since the procedure in both moving bed and static bed reactors is well known. detailed disclosures of such reactors and of conventional regenerating methods and apparatus are omitted.

Referring again to the drawing, the vaporized vis-broken and desalted product leaves zone A in vapor phase by line I and, if from a sweet crude, may be passed by lines 5 and 6 directly to fractionating zone B. However` if the charge is corrosive, it is given a preliminary selective cracking and desulphurizing treatment in zone C on being fed thereto by valved line 1. In zone C the vaporized products from zone A are subjected to the action of low activity cracking catalysts, with orl without desulphurizing catalysts. Any known catalysts suitable for these purposes may be utilized. For mild cracking, catalysts from natural or activated clay or synthetically produced catalysts, with or without treatment to adjust activity, are suitable but they should have an activity index in the range of 10 to 25. The activity index states the liquid volume percent of light products which the catalyst is capable of producing from a standard charge stock under standard operating conditions, the test procedure being described for example in detail on page 2 of United States Patent No. 2,347,216, issued to Albert G. Peterkin on April 25, 1944, or, as another example. as expressed in terms oi the standard test described in "Laboratory Method for Determining the Activity of Cracking Catalysts, by J. Alexander and H. G. Shimp, page R537, National Petroleum News, Technical section. August 2, 1944. For additional desulphurization in zone C, a suitable catalyst is a metallic oxide, for example, the oxides of nickel, cobalt,

etc. on an inert support such as celite or other porous inert material. One such desulphurizing agent or catalyst is disclosed in United States Patent No. 1,775,366, issued September 9, 1930, to Alfred Joseph. The proportion of desulphurization catalyst to mild cracking catalyst in zone C will depend upon the quantity of corrosive components in-the crude charging stock. For most operations the proportion will be of the order of one part by volume of desulphurizing agent or catalyst to ten parts of cracking catalyst. The quantity of active material in zone C is determined by the amount of reaction required to effect the necessary desulphurization. In general, it will be of the order of one volume of catalyst or catalyst-containing mixture to two volumes of fresh charge (liquid basis) per hour.

For zone C, fixed bed reactors with circulated heat exchange media for temperature control may beutilized, or there may be utilized a moving bed system, or the so-called fluid system in which the catalysts are in powdered form and mixed with the charge, or converters having one or more sections in which inert heat retaining material is mingled with the catalysts for temperature control. In zone C, a cracking catalyst is used having low activity as stated. The cracking operation proceeds under conditions such that the degree of cracking is small as measured by conversion of the charge to gasoline and gas. Generally, it is preferred that the pressure and temperature within the zone C as well as the feed rate of the charge thereto be selected so that no more than 25% and preferably no more than 20% of the charge is converted to gasoline and gas.

The pressure, preferably, is low as from atmospheric pressure to rI pounds per square inch. The temperature of the contact material within said zone should be in a range from 800 F. to 1100'J F'. The feed rate of the charge should be relatively high and, usually, should be in excess of one volume of charge (liquid basis) to one volume of catalyst per hour. In most instances, the vaporized products from zone A will issue from the latter at a suitable temperature to be passed directly to zone C without intermediate heating or cooling. The products leaving zone C pass through lines 8 and 6 to fractionating zone B.

Fractionation may be effected in zone B in any known or desired manner and with any suitable equipment. Usually, gasoline and gas will be taken as an overhead fraction, Aas by line 9, the heaviest products will be removed as a bottoms fraction as by line I0, and one or more side stream fractions, such as naphtha or gas oil, may be removed by line i l, for example. The bottom fraction is a suitable fuel of excellent quality and it `may be withdrawn in whole or in part by line Illa. Similarly a side stream fraction may be withdrawn from the system in whole or in part by line Ha.

If further conversion of products from fractionating zone B is desired, either the bottom fraction or one or more side stream fractions, or any combination of the same, may be sent by line l2 through suitable heating means I3 (the use of which is optional) to a cracking zone D of any known or desired type, whether thermal orcatalytic and if catalytic, whether fixed bed, moving bed, fluid type, etc. All or a portion of the cracked vaporized products which leave cracking zone D by line M may pass directly into line 3 and thus be added to and mingled with the fresh charge to zone A supplied by line 2. Or, under some circumstances, a portion of said cracked vaporized products may be passed to a fractionating zone by a line |411. Substitute or additional vapors or vaporizing media from any source may be supplied by line l5. Alternatively, as hereinafter described, the cr-acking zone D may comprise a plurality of spaced contact masses traversed in series by material passing along the line l2. Simultaneously, suitable hydrocarbon material is admitted to the respective chambers dened by each pair of adjacent contact masses.

From the above it will be apparent that the invention provides for the complete conversion oi heavy charging stock into lighter products without the recovery of tarry or asphaltic materials, the latter being intercepted in the vaporizing vis-breaking and desalting zone A, for the production in zone A of clean products for fractionation in zone B with necessity for intermediate treatment in zone C only when the fresh charge is corrosive, and for fractionating in zone B of final products which may be separated out for immediate use or for further conversion. Any available cracking equipment in a renery can be utilized for zone D in the system, even if the cracking is effected thermally with the production of tarry bottoms, for the final products which are recovered in fractionating zone B will still not contain tarry or asphaltic material since the same will have been intercepted and retained by the contact mass in zone A when the cracked vaporized products from zone D are added to and mingled with the fresh charge fed by line 2. Certain advantages arise from using the selective cracking and sweetening operation of zone C even when the nature of the charging stock does not make such use necessary, for by its use a better cracking stock is prepared for separation in zone B, protection is given to subsequent cracking catalysts which may be utilized in zone D, and a more suitable boiling range of heavy cracking stock and a greater proportion of material in the gas oil or domestic fuel boiling range is prepared for separation in fractionating zone B.

Preferably, the hot hydrocarbon vapors traversing the line 3 are mixed with the fresh charge prior to engagement thereof with the contact mass in the Zone A. The quantity of hydrocarbon vapors traversing said line 3 should Ibe sufficient to cause the contact time of the vapors in the zone A to be short as hereinbefore described. In addition, the quantity thereof should be sufcient, depending on the relative temperatures of said hydrocarbon vapors and the fresh charge together with the character of the latter, to produce a partially vaporized mixture of desired character for subsequent engagement with the contact mass. In the event that the charge supplied to the zone A is of such character that the quantity of hydrocarbon vapors traversing the line 3 is insufficient for the purposes stated above or for any other desired purpose. distillate hydrocarbon material in vapor phase, if sulphur-bearing, may be introduced into the system by the line la. If not sulphurbearing, such distillate hydrocarbon material may be admitted to the system by the line I2a.'

Referring to Fig. 2, I have shown a vaporizing and viscosity-breaking zone AI wherein a suitable casing or shell 2) contains a desired number of contact masses I which are supported by suitable apertured partitions 2|. The casing 20 and the contact masses I define a plurality of chambers 22 into which, by the respective valve- 7 controlled branch lines 23a, 23h, 23e of a lino 23, heavy hydrocarbons, as hereinbefore described, while at least partly in the liquid phase, are introduced in the manner hereinafter described. Each of the chambers 22 should contain an arrangement for atomizing the liquid phase portion of the heavy hydrocarbons admitted thereto and this is exemplied by the nozzles 23d which are secured to the respective branch lines 23a, 23h and 23e.

The contact masses I, as hereinbefore described with respect to the zone A, are formed from solid contact material which is substantially inert catalytically. Preferably, as disclosed in my aforesaid application Serial No. 505,109 with respect to spaced contact masses utilizable for conversion purposes, the contact masses I of Fig. 2 are subjected, after an on-stream period, to a regenerating operation which stores in said contact masses heat in excess of that required for supplying reaction heat during the subsequent on-stream period. With heat thus stored in the contact masses I in the manner just described and with the temperature thereof in a range such as hereinbefore described with respect to the contact material in the zone A prior to the beginning of an on-stream period, hot hydrocarbon vapors are admitted to the chamber 22 above the upper contact mass I to initiate an on-stream period of the system shown in Fig. 2. Simultaneously, heavy hydrocarbons, while at least partly in the liquid phase, are introduced into the chambers 22 -by way of the respective branch lines 23a, 23h and 23e.

The temperature of the heavy hydrocarbons traversing the branch line 23a should be lower, to suitable extent, than that of the hot vapors entering the shell by way of the line 3. Therefore, in the upper chamber 22 exchange of heat occurs between the hot vapors and the heavy hydrocarbons as atomized by the nozzle 23d or equivalent. As a result, there is produced in said upper chamber 22 an atomized mixture having temperature lower than that of the upper contact mass I, this being true by reason of the fact that the temperature of the heavy hydrocarbons traversing the branch line 23a is at a suitable low magnitude as stated above. As the operation proceeds, the partially vaporized mixture passes into and is deposited on the upper contact mass I with resultant vaporization and viscosity-breaking of the dillicultly vaporizable components thereof and, from said upper contact mass, a stream of hot vapors passes into the chamber 22 directly therebelow at temperature which has been elevated by said contact mass. The temperature of the heavy hydrocarbons admitted, while at least partially in the liquid phase, to the chambers 22 by the respective branch lines 23h, 23e is lower, to suitable extent, than the hot vapors entering said chambers from the respective contact masses positioned directly thereabove. Therefore, in each of the said last named chambers 22, a heatexchange operation occurs in the manner described with respect to the upper chamber 22 and, in each of the two lower contact masses I, a vaporizing and viscosity-breaking operation occurs with respect to the liquid phase hydrocarbon material passed thereinto. The resulting vaporized products pass from the shell 2U by way of the line 4 and, thereafter, in the zones C and/or B, the operation may be the same as hereinbefore described with respect to Fig. 1.

Referring further to Fig. 2, I have shown a cracking zone DI wherein a suitable casing or shell 8 30 contains a desired number of contact masses C which are supported by suitable apertured partitions 3 I. The casing 30 and the contact masses C define a plurality of chambers 32 into which. by the respective valve-controlled branch lines 33a, 33h, 33e of a line 33, hydrocarbon material is introduced in the manner hereinafter described. This hydrocarbon material may be of any suitable character such, for example, as fresh distillate gas oil or recycle material traversing the line I2. It may be totally liquid, totally in the vapor phase or partly in each phase. It will be understood that the hydrocarbon material thus introduced to the system by line 33 increases the quantity of hot hydrocarbon vapors traversing the line 3. As disclosed in my aforesaid application Serial No. 505,109, the contact masses C may comprise catalytic material suitable for effecting a cracking operation and, if required, additional inert material having high heat capacity. In the same manner as described with respect to the contact masses I in the zone AI, the contact masses C, prior to the start of an on-stream period, should have stored therein heat in excess of that required for reaction purposes and the temperature thereof should be within the cracking range of approximately 800 F. to 1200 F.

Upon initiation of the described on-stream period of the system shown in Fig. 2, the selected fractions from the zone B may traverse the line I2 and be subjected to temperature elevation in the heater I3. Thereafter, they enter the lower chamber 32 of the casing 30. The hydrocarbon material entering the chambers 32 by way of the respective branch lines 33a, 33h and 33C has temperature lower, to suitable extent, than that of the hydrocarbon products which traverse the line I2 and enter said chambers in succession. Accordingly, as described with respect to the zone AI, a heat-exchange operation is effected in each of the chambers 32 of the casing 30. As the operation proceeds, the hydrocarbon material traversing the contact masses C is cracked and the resulting cracked, vaporized products leave the casing 30 by way of the line I 4.

As stated, the hydrocarbon material traversing the branch lines 33a, 33h and 33e may be entirely vaporized or it may be at least partly in the liquid phase. If the latter condition obtains, suitable atomizing arrangements may be provided therefor in the respective chambers 32 and, in each of the chambers, entire or partial vaporization of the liquid phase material last named may be effected as desired.

It has been hereinbefore stated that the temperature of the hydrocarbon material charged into the chambers 22 of the zone AI and the chambers 32 of the zone DI is lower to suitable extent than the vapors passing into said chambers from the respective contact masses. Obviously, the temperature of such hydrocarbon material will vary with the quantity thereof, increase in quantity being accompanied by increase in its temperature and vice versa. In general, the temperature of such hydrocarbon material may be substantially lower, for example, F. to 125 F., than that of the aforesaid vapors although, as just stated, the temperature of such hydrocarbon material will vary in accordance with the quantity thereof. In any event, it is important for the hydrocarbon material to be introduced into the chambers 22 and 32 under conditions such that approximately the entire quantity of excess heat in the contact masses is absorbed thereby.

If desired, a valve-controlled line la may branch from line 4 and be extended to the hereinbefore described line 2, said line la including a. suitable cooler if desired. By the line V4a, vapors produced in the zone A and having suitable temperature, as determined by the cooler,

' may be returned to said zone, under the influence of a suitable pump or equivalent, not shown, and admitted thereinto along with the fresh charge traversing the line 2. The vapors passing through the line 4a may be used in lieu of or they may supplement the cracked vapors traversing the line 3. When and if admitted to the zone A, it will be understood that the vapors passing through the line 4a function substantially the same as herenbefore described with respect to the vapors traversing the line 3.

With respect to the invention as herein disclosed, it shall be understood that, if desired, a single bed vaporizer may be utilized with a multibed cracking unit and, further, that a multi-bed vaporizer may be used with a single bed cracking unit.

For purposes of explanation and without limitation of the invention, the following example is included as a part of this specification.

A converter having three separate contact masses formed from pieces of fused silica and alumina each having a major transverse dimension of about 1/4 to of an inch was operated as follows: Cracked hydrocarbon vapors including cracked gasoline and xed gas, produced as hereinafter described, and having temperature of ap-` proximately 935 F. were charged into one end of the converter under pressure of 23 pounds per square inch and at a rate, compared with the total volume of contact material in said converter, of 2.1 volumes (liquid basis) per hour. Into the space in advance of each contact mass, there was admitted a stream of a heavy oil, together with 15% of steam by weight, which was the 43% through 100% cut of East Texas crude having the following boiling range characteristics as determined by vacuum assay: 5% at 486 F., 50% at 663 F. and 89% at 1005 F. VThe charging rate of each stream of heavy oil, compared with the total volume of contact material in said converter, was 0.4 volume (liquid basis) per hour. At the beginning of the on-stream period, the following temperature conditions existed with respect to the contact masses: The rst contact mass at the respective entrance and exit sides thereof had temperature of 1000" F. and 910 F.; the second contact mass at the respective entrance and exit sides thereof had temperature of 950 F. and 945 F.; and the third contact 'lass at the mid-point and exit sides thereof had temperature of 920 F. At the termination of the on-stream period, the following temperature conditions existed with respect to said contact masses: The first Contact mass at the respective entrance and exit sides thereof had temperature of 865 F. and 870 F.; the second contact mass at the respective entrance and exit sides thereof had temperature of 850 F. and 855 F.; and the third contact mass at the respective midpoint and exit sides thereof had temperature of 860 F. and 870 F. The heavy oil, While substantially in the liquid phase, was admitted to each of the aforesaid spaces at a temperature of 600 F. By action thereon of the stream of hot vapors, the heavy oil was vaporized to some extent and, therefore, in each space, a partially vaporized mixture was produced having temperature lower than that of the succeeding contact mass.`

Hence, a partially vaporized mixture was admittd to each contact mass with resultant vaporization and viscosity-breaking of the liquid phase material, the totally vaporized mixture leaving each contact mass at temperature which had been elevated toward that of the contact mass. The contact time of the vapors in the rst, second and Vthird contact masses was, respectively, 2.8 seconds, 2.3 seconds and 1.9 seconds.

Of the heavy East Texas bottoms admitted in advance of each contact mass, more than 96% by Weight was discharged from the converter as vaporized material admixed with the cracked vapors Iwhich were admitted to said converter. The remainder, less than 4% by weight of said heavy East Texas bottoms, was retained in the contact mass as a deposit of coke or carbonaceous material containing substantially all of the inorganic saits and other non-volatile inorganic material present in said bottoms as well as the coke or carbonaceous material resulting from conversion of the diicultly vaporizable components of the bottoms.

The vaporized material discharged from the aforesaid converter was passed to a selective cracking and desulphurizing zone where it was subjected under mild cracking conditions to the action of mild cracking catalysts to break down sulphur and corrosive compounds.

The vaporized material from the zone last noted was sent to a fractionating zone from which a side stream fraction in the form of a light gas oil was passed through a heater in order to produce vapors which were admitted to a cracking converter at a temperature of 850 F. The A. P. I. gravity of this light gas oil was 29.3, the initial boiling point was 480 F., the 50% boiling point was 558 F., and the 95% boiling point was 723 F. The vaporized gas oil was thus charged to the cracking converter under pressure of 23 pounds per square inch and at a rate, compared with the total volume of contact material in the cracking converter, of 0.75 volume (liquid basis) per hour. The cracking converter had six separate contact masses formed from equal parts of pieces of fused silica and alumina, as hereinbefore described, and pieces of catalytic contact material having an activity index of 25 as expressed in terms of the standard test described in Laboratory Method for Determining the Activity of Cracking Catalysts, by J. Alexander and H. G. Shimp, page R537, National Petroleum News, Technical section, August 2, 1944. The respective contact masses were formed from progressively increasing amounts of contact material. Thus, the contact mass rst engaged by the aforesaid vaporized material was formed from 4.5 liters of contact material and the succeeding contact masses were formed, respectively, from 5.3 liters, 6.2 liters, 7.3 liters, 8.5 liters and 10.0 liters of contact material.

Into the space in advance of each contact mass, with the exception of the rst (that contact mass which is rst engaged by the vaporlzed gas oil), there was admitted, together with 10% of steam by weight, a heavy gas oil in the form of a bottom fraction from the aforesaid fractionating zone.V The charging rates of the respective streams of heavy gas oil, compared with the total volume of contact material in the cracking converter, which were admitted in advance of the second, third, fourth, fth and sixth contact masses were, respectively, 0.11, 0.13, 0.15, 0.17 and 0.19 volumes (liquid basis) per hour. The A. P. l. gravity of this heavy gas oil was 23.9, the initial boiling point was 476 F., the 50% boiling point was 640 F., and the 93% boiling point was 762 Il'.

This heavy gas oil, while in the liquid phase, was admitted into each of the aforesaid spaces, except the nrst, at a temperature of 275 F. and, by action thereon of the streams of vaporized material, it was substantially completely vaporized. Therefore, in each of said last named spaces, a vaporized mixture was produced having temperature lower than that of the succeeding contact mass. From each space last referred to, then, a vaporized mixture passed into the succeeding contact mass with resultant elevation in temperature and conversion thereof into hydrocarbon products. During the on-stream period. the average temperature of the vapors entering and leaving each contact mass was substantially as follows: First contact mass, 850 F. and 950 F.; second contact mass 852 F. and 940 F.; third contact mass, 860 F. and 915" F.: fourth contact mass. .865 F. and 975 F.; fifth contact mass 870 F. and 940 F.; and sixth contact mass, 870 F. and 1000" F.

The cracked hydrocarbon vapors leaving the cracking converter were passed to the vaporizing converter and charged into the inlet end thereof as and for the purpose hereinbefore described.

The East Texas bottoms supplied in advance of the beds of the vaporizing converter constituted the total fresh charge to the system. Based on this fresh charge, the product which was obtained as an overhead fraction in the fractionating zone consisted of (1) 60% gasoline by volume having the following characteristics: pounds per square inch, Reid vapor pressure, 90% boiling point, 365 F.; (2) 18.9% gas oil by volume having an end boiling point of approximately 800 F. suitable for use as distillate fuel; and (3) 18.3% gas by weight. The amount of coke or carbonaceous material produced in the system was 13% by weight of the total charging stock.

While Vthe invention has been described with respect to certain particular preferred examples which give satisfactory results, it will be understood by those skilled in the art, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention and it is intended, therefore, in the appended claims to cover all such changes and modications.

I claim as my invention:

1. In the conversion of all of a heavy hydrocarbon fraction containing tarry or asphaltic material to volatile hydrocarbon products and coke, the process which comprises elevating the temperature of contact material which is substantially inert catalytically into a range which is effective for the purpose hereinafter specified, mingling a charge of said heavy hydrocarbon fraction, while at least partially in the liquid phase, with cracked hydrocarbon vapors having a temperature higher than that of said charge and produced as described below to obtain a mixture having temperature above 750 F. but lower than that of the contact material as elevated in temperature, contacting said mixture with said inert contact material as elevated in temperature and while disposed in a vaporizing and viscositybreaking zone to thereby vaporize the charge in response to passage of heat thereto from said contact material, fractionating the vaporized products produced in said zone so as to produce distillate fractions having different boiling ranges, cracking at least one of said distillate fractions escasas in a cracking zone under conditions, including temperature above about 750 F., such that hot cracked hydrocarbon vapors having temperature higher than that of said charge are produced, and mingling at least a portion of the hot cracked hydrocarbon vapors so produced, while at temperature higher than that of said charge, with the charge as described above, whereby heat contained in the hot vapors leaving the cracking zone is supplied to said vaporizing and viscosity breaking zone to assist the conversion therein.

2. The process of claim 1 in which the vaporized products are subjected to desulfurization prior to yfractionation thereof.

3. The process of claim 1 in which the fraction clix-lacked has a boiling range above that of gaso- 1 e.

4.*The process of claim 1 in which all of the cracked hydrocarbon vapors from the cracking zone are mingled with the charge of said heavy hydrocarbon fraction.

5. The process of claim l in which the fraction cracked is the bottoms fraction produced by fractionating the vaporized products from the vaporizing and viscosity breaking zone.

6. In converting heavy or residual hydrocarbon fractions without recovery of tarry or asphaltic materials, the process which comprises elevating the temperature of contact material which is substantially inert catalytically into a range which is eilective for the purpose hereinafter specied, mingling a charge of said hydrocarbon fractions with cracked hydrocarbon vapors having temperature higher than that of said charge and produced as described below to obtain a mixture having temperature above 750 F., contacting the mixture with said inert contact material as elevated in temperature and while disposed in a vaporizing and viscosity-breaking zone to thereby vaporize the charge in response to passage of heat thereto from said contact material. sending the products from said zone to a cracking zone and subjecting them under cracking conditions to desulphurization and mild cracking in the presence of cracking catalyst,

fractionating the products produced in said last named zone, cracking a resulting fraction with resultant production of cracked hydrocarbon vapors having temperature higher than that of said charge as aforesaid, and utilizing at least some of the hydrocarbon vapors last named as the high temperature hydrocarbon vapors which are contacted with the inert contact material along with the charge as described above.

7. In converting heavy or residual hydrocarbon fractions without recovery of tarry or asphaltic material, the process which comprises elevating the temperature of contact material which is substantially inert catalytically into a range which is effective for the purpose hereinafter specified, mingling a charge of said hydrocarbon fractions, while at least partially in the liquid phase, with cracked hydrocarbon vapors having temperature higher than that of said charge and produced as described below to obtain a mixture having temperature above 750 F. but lower than that of the contact material as elevated in temperature, contacting the mixture with said inert contact material as elevated in temperature and while disposed in a vaporiznj; and viscosity-breaking zone to thereby vaporize the charge in response to passage of heat thereto from said contact material, sending the products from said zone to a cracking zone and subjecting 7s them under cracking conditions to desulphuriza- 13 14 tion and mild cracking in the presence of crack- REFERENCES CITED ing catalyst, fractionating the products produced in said last named zone. cracking a resulting ml fllgvgxferences are of record in the fraction with resultant production o1' cracked hydrocarbon vapors having temperature higher 5 UNITED STATES PATENTS than that of said charge as aforesaid. and utiliz- Number Name Date ing at least some of the hydrocarbon vapors last 2,161,677 Houdry June 6, 1939 named as the high temperature hydrocarbon 2,166,177 Peterkin July 18, 1939 vapors which are contacted with the inert con- 2,235,639 Koch Mar. 18, 1941 tact material along with the charge as described l0 2,282,451 Brooks May 12, 1942 above. 2,378,531 Becker June 19, 1945 EUGENE J. HOUDRY. 2,388,055 Hemminger Oct. 30, 1945 2,393,028 Dunham Jan. 15, 1946

Claims (1)

1. IN THE CONVERSION OF ALL OF A HEAVY HYDROCARBON FRACTION CONTAINING TARRY OR ASPHALTIC MATERIAL TO VOLATILE HYDROCARBON PRODUCTS AND COKE, THE PROCESS WHICH COMPRISES ELEVATING THE TEMPERATURE OF CONTACT MATERIAL WHICH IS SUBSTANTIALLY INERT CATALYTICALLY INTO A RANGE WHICH IS EFFECTIVE A CHARGE OF SAID HEAVY HYDROCARBON FRACTION, WHILE AT LEAST PARTIALLY IN THE LIQUID PHASE, WITH CRACKED HYDROCARBON VAPORS HAVING A TEMPERATURE HIGHER THAN THAT OF SAID CHARGE AND PRODUCED AS DESCRIBED BELOW TO OBTAIN A MIXTURE HAVING TEMPERATURE ABOVE 750*F. BUT LOWER THAN THAT OF THE CONTACT MATERIAL AS ELEVATED IN TEMPERATURE, CONTACTING SAID MIXTURE WITH SAID INERT CONTACT MATERIAL AS ELEVATED IN TEMPERATURE AND WHILE DISPOSED IN A VAPORIZING AND VISCOSITYBREAKING ZONE TO THEREBY VAPORIZE THE CHARGE IN

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