US2393333A - Chemical process - Google Patents

Description

Y Jan. 22, 1946. c. Q. MlLsouRNE 2,393,333 I CHEMICAL PROCESS Filed Nov. 21', 1944 2 sheets-sheet 1f 'is applicable to processes in vvaporized.- for example in a continuous beftcge its introduction into the cyclicly heatedv pa y 'inthepresenceofadiluentgaa Patented-Jan. l22, 1946 UNITED. -STATES PATENT wFF-CE Charles Gordon Milbourne, Los Angeles, Calif.,

asslgnor to The United Gas Improvement Com- 1 pany, a corporation of Pennsylvania application November 21, 1944', serial No. 564,540

` facture of combustible gas are the well known cyclic oil gas processes, carburetted water gas processes, and. hydrocarbons gas reforming processes.

Typical of the fluidhydrocarbon materials l pyrolyzed' in such processes `are crude petroleum oil and fractions thereof, such as naphtha, gas oil, fuel oils and reslduums; natural gas; renery oil gas; and sometimes tars derived from the Dyrolysis of petroleum oil or coal. Some of these materials contain non-hydrocarbon components in addition to their hydrocarbon constituents.

The invention, for convenience, will be described in connection with the employment of crude petroleum oil or a fraction thereof, which for convenience will be referred to generally as oil, although it is to be understood that the invention is applicable to the pyrolysis of 'other fluidhydrocarbon material.

The invention, also for convenience, will be described in connection with the introduction 'of the oil to the cycliclyheated gas making path in the liquid phase. for vaporization therein, although it is to be understood that' the invention tube still,

In the cyclic manufacture o f oil gas, a gas set comprising a vessel or vessels, provided with a refractory 'lining or linings and with refractory checker brick, is heated during the heating period of the cycle, termed the blow, by the combustion of fuel such as oil. tar or combustile gas, Vand by the passage of tion products through the vessel or vessels, thereby raising the refractory lining or linings and checker brick to elevated temperatures and storing 'heat therein to provide a path of stored heat.

After theffblogffh been terminated, a run" is made in' which oil is sprayed into the 'gas set auch for example auteannand vaporlned therein. the resulting oil which the oil is" Vucts of combustionk to the --a water gas run" sels, in which the i purse blast vapors being passed along the path of stored heat .with the steam and cracked therein by the stored heat to produce oil gas.

The cycle also includes steps for purging prodatmos'phere, and for purging oil gas to storage. f

' In the manufacturer of carburetted water gas,

an ignitedv bed or solid fuel, in a generator. is

,blasted with air and raised to a high tempera- A ture. The resulting blast products are burned with; secondary air, refractory lining and checker brick of a carburetting vessel or vessels, lproducing a path of blast, termed the blow ismade in which steam is passed through the highly heated fuel bed, generating blue water gas, which together with the excess steam -is passed along the path of stored heat in'theheated carburettlng vessel or ves- 'blue water glas is carburetted with oil, which is sprayed into the set, vaporized, and the vapor cracked by thestored heat in the presence' ofthe blue water sas.

' Purgin'g steps are performed in the Acycle to products to the atmosphere, and to purge carburetted water gas to storage..`

In normal cyclic oil gas and earburetted water gas practice, by far the larger part of the petroleum oil, which customarily comprises theless costly fractions of the crude such as gas oil and heavy residuuma finds its way into fixed gas or in other words into gases-which are liquefied with diiliculty, auch as hydrogen, methane, ethylene,

the resulting hot combus- 35% fines. Neverthelessl a 1 The tar. drip oil and possibly other' gaseous parailines and oleis used up in the production of tar, drip. oil and lower temperature'condensates, the quantity of the latter recovered depending upon vthe final temperature to whichthe gas is reduced before delivery to. a gas holder for distribution.

and lower temperature condensates contain awide variety of hydrocarbons, the number and quantity of which vary with the final temperature to which the gas is subjected.

- As an example hydrocarbon such as benzene,

toluene. xylene, naphthalene, anthracene, indene,

styrene. methyl prene, piperylene, butadiene, etc., might be detected in small quantities or recovered in substantial amounts. All of these hydrocarbons are valuable. p pounds perhaps more under normal gas small quantities only 'so than the others, because are produced.

and their heat stored in the f certain portion of the oilY styrene, cyclopentadiene, isothe unsaturated resin formlngcom v` manufacturing conditions` :From the standpoint ofl manufacture of gas ior distribution, these cyclic processes here been developed to a high-degree oi' eciency.

interior oi tubes presents operating diiliculties, besides in some cases exerting an -'undeoatalytic enect upon course of the pyroiysis. cyclic processes oi the general character oi d those above, the continual recurrence oi the heetins period eords and frequent opporior on deposited carbon, preventing accumulation and providing a substantially carbon free path ci pyrolysis at the oegunning ci each gas inciting rum ln the usual methods of operating these cyclic processes for the production of ses for distribution, however, even should the required oonditions for a high yield ci a given hydrocarbon oi good duality be accidentally attained in a portion oi the gas making path, and during a portion oi" the @as making "suny other portions of the ses making path and other portions of the gas malsins run may provide cracking conditionsiar removed from those 'which are desirable from the `stsiidpouit of production of the desired hydrocarbon material.

En the heating step of the cycle, in establishing temperature 'conditions approximating the desired temperatin'e conditions in the downstream portion of -the path of the heatingr gases suitable for effecting the desired'pyrolysis therein, it is extremely dimcult to avoid setting up temperature conditions in the upstream portion of the heating path, which are enurely too severe for the desired pyrolysis v During the gas f1.1; :i -run, due to thefact that the `stored heat in the path of pyrolysis is .being continually abstracted in the vaporization of the oil and the pyrolysis of the resulting vapors with consequent cooling of the heat storage material, thereis e continuel shift, during the run, toward pyrolysis conditions of decreased se- Verity as the run proceeds, which is indicated by the swine, with respect to time, of observed tenipetures at various points in the gas making pa v v 'The swing in pyrolysis conditions, throughout the gas making rum may be decreased by the escasos suing, volvo operations to up disproportionate portion ci the cycle, The time cccupied by purses may also .be disproportionate, or if it is not, an undue contamination of the make gas with combustion gases. or an undue loss or make gas to the atmosphere may take place.

The present invention is directed to the provision of a novel cyclic process of the above general character in the performance of which a greater uniformity of pyrolysis may be effected and greater yields of desired valuable hydrocarbons in good quality secured.

According to the present invention, during the first portion of Athe run, 'only a portion ci the entire path of stored heat established during the blow is employed as the path of pyrolysis, and during the run the path ci? pyro' s si loneitudinelly within the path of such manner that the succeechng; run is conducted under pyrolysis closely approximating pyrolym existing in the path of pyrolysis oi the run, than did those existing in the path of' pyrolysis immediately before the shift.

Stated otherwise, during the run after the pyrolysis conditions existing in the path oi pyrolysis tions more effect those at the beginning ci the run have been moderated employment of refractory heat storage material of relatively high heat conductivity as compared with that o1 the usual re clay brick, such for example as bricks of'bonded silicon carbide or l carborundum. Such refractory material has the capability of rapidly transferring heat fromthe outside surface to the interior during the blow,

and from the interior= to the outside surface of the brick, during the run,.thereby maintaining more uniform surface temperatures'. Y

unv operations with any given -oll input rate. There is a practical limit to the shortening of cycle time, however, in that, with continued. sh0rtdue the cooling action of the pyrolysis upon that portion ci the path ci stored employed as the path or pyrolysis, the path ci pyrolysis is shifted lengthwise within the path ci? stored heat, so as to alter the pyrolysis conditions in the direction o.. greater intensity o cracking and so as to approximate more closely the intensity of the cracking edected at the beginning of the run, whereby greater uniformity of cracking is attained. l

The shift of the path of pyrolysis within thev path oi stored heat during the run may be made in a number of ways depending, among other things, upon the temperature conditions set up in the path of stored heat during the b1oW, upon the particular portion oi the path'of stored heat employed during the initial part of the run, and upon the degree of compensation in pyrolysis conditions to be effected by the shift of the path of pyrolysis.

The restoration of pyrolysis effect produced by the shift of the path of pyrolysis during the run may be' obtained by shifting the path of pyrolysis so as to compensate for reduced temperature con- I ditions by increased time of contact, or by shifting the path of pyrolysis so as to operate during .the succeeding portion of the run with substantially the ssmetemperature and time of contact as at the start of the run, or even by shifting the path of pyrolysis so as to operate under more severe temperature conditions and with shorter time of contact, than those obtaining at the start ofthe run. v

The shift in the path of pyrolysis within the path of stored heat may be conveniently made by shifting either the point ofadmisslon of the oil to the path of stored heat, or the point of exit of the products of pyrolysis therefrom, or both.

'Other features o! 'the invention reside in the steps, combination ot stepsrsequence o! steps,

and in the commotion, combination, andarrangement of parts, all of -,which together with other features will become more apparent to persons .skilled in the art as the specification proceeds, .and .upon reference to the drawings, in

illustrating the process o! the present invention;

be more particularly described in connection. with, the manufacture of oil gas, although it is applicable as before stated to other processes in which fluidvhydrocarbon material isv pyrolyzed.

Referring to Figures 1 to 5: A

In all of the Figures 1 to 5, the path of stored heat established during the blow portion of the cycle is indicated by the shaded rectangle having an upstream end at I and a downstream end at 2.

In the operation diagrammatically illustrated in Figure 1, during the first part of the gas making run," oil is introduced to the path of stored heat at 3,whi'ch isdownstream from I, while a diluent gas such as steam is introduced at I, the products of pyrolysis and steam leaving the path of stored heat at 2. v

During a later portion of the gas making run, and after the moderation of excessive temperatures in the upstream portion of the path -oi? stored heat by the cooling effect of the steam, the admission of the oil is shifted upstream to 4, the products of pyrolysis and steam still leaving the path of stored heat at 2.

It will be seen that the path of pyrolysis in the first portion of the run extended within the path of stored heat from 3 to 2, While in the second portion of the runthe path of pyrolysis -was'shifted so that it extended from 4 to 2. The

time of the shift and the degree of the shift and other conditions are chosen so that while the Pyrolysis conditions existing in the longer path from 4 to 2 at the time of the shift are somewhat more severe thanA those existing at the time of the shift in the shorter path from 3 to 2, theyl closely approximate in effect the conditions of pyrolysisexisting in the shorter path at the outset of the run. A'measure of the intensity of the cracking effected in the several portions of v the run may be obtained by a comparison ofV the density relative to air of the gas produced in the several portions of the run, as will be more -particularly described hereinafter.

In the operation diagrammatically illustrated in Figure 2, during the first portion of the run, l

the oil is introduced to the path of stored heat 'mitted to the path Iof Figurev 1 except l 3 the oil is introduced downstream at 1, while a diluent gas such as steam is introduced at I. The resulting products of pyrolysis and steam leave the path of stored heat at 2.

During the second portion ofthe the upstream portion of v has' been sufiiciently cooled by the passage of run,. after steam therethrough, the admission of the oil is.

shifted upstream to 9, and the point of removal of products of pyrolysis and steam shifted upstream to 8. i A

In this case, the path of pyrolysis .in the latter part of the run extending from 9 to B may be longer, shorter or the same length as the path of pyrolysis in the first portion of the run extending from I to 2.' In any case, otherv conditions such as temperature, rate of oil and steam admission etc. are such as to produce a pyrolyzing effect in the path of pyrolysis from 9 to 8 somewhat more severe than that existing in the path of pyrolysis from 'I to 2 at the time of the shift, but closely approximating pyrolyzing effect of the pyrolysis conditions in the path from' to2 ,at the outset of the run." 1

In the voperation diagrammatically illustrated in Figure 4, during the rst portion of the oil is introduced to the path of stored heat at I0, while a diluent gas such as steam is introduced at I. The products of pyrolysis and steam leave y the path of stored heat at I I.

During a later portion of the run, oil isl adof stored heat at I2, which I0, and downstream from I, steam continuing to he admitted at I. During this portion of the run, the resulting products of pyrolysis and steam are taken off at 2,` which is downstream from II. 'fifif As in the case of the previously. described operations, the shift in the pyrolyzingffpfath, during the run is to'compensate for. moderation of pyrolyzing conditions during the earlierl portion of the run and to. securegreater uniformity o f cracking. In Figure 5, the

is upstream from that the upstream portion of the pathof stored Ila-finto two parallel portions I3 During the first portion of the and I4.

run oil is admitted to the path of stored heat downstream at I5, with steam supplied at I to either or both l of the parallel portions I3 and Il, the resulting at 5, a diluent gas such as steam being introduced upstream at I. The products of pyrolysis and.

` `steam leave the path of stored 'heat during the rst portion of the run at 6 which Vis up stream from 2. f

During a later portion of the run, with the oil and steam admissions unchanged, the point of removal of the products of pyrolysis and steam is shifted downstream to 2.

During the first portion ofthe ruin the path of pyrolysisextended within the path of stored heat from 5 to 6, while during the latter portion vof the run it -was shifted so as to extend from As in the previous operation, the time, 'degree and other conditions of theshift are chosen so pyrolysis products and steam being taken off at 2.

During a later portion of the runthe oil admission at ,I5 is terminated and oil admitted at I6, which is upstream from I5 and downstream from I. Steam is admitted at tions of the path of stored heat I3 and I4, the.

' steam admittedthrough portion Il providing a .diluting medium in the oil vaporization zone as well as carrying heat from the upstream end of the path of stored heat into the path of pyrolysis.. The steam admitted through I3 carries heat from this portion of the path of stored heat into' a downstream'portion of the path of pyrolysis, by-

that the pyrolyzing eifect of 'the longer path of pyrolysis, while somewhat more severe than that of the shorter path of pyrolysis at the time of the shift, closelyA approximates the pyrolyzing ei'fectof the shorter path .at the outset of the Irllnl1 In ,the operation ditically illustrated 121 3,

during the first portion of the "run pyrolysia Appropriate -of pyrolysis from Il to passing the upstream portion of the path of proportioning of the steam admitted through Il and lIl provides a further control of the uniformity of cracking. y

The resulting pyrolysis products and steam during the later portion of the run are taken of! at 2 as before.

'I'he greater time of contact of the longer path l 2 as compared with that from Il to- 2, compensates for lower temperature conditions, with a result that the intensity thepath of stored heat "run,"

operation is lsimilar to that i heat is divided by partition I to both parallel poras provided with the supply. means Il of a cooling and scrubbing liquid such as water.

As the gas sample passes upward through the scrubber-coolen. it .is scrubbed and cooled to remove entrained tar particles or other entrainedmaterial, and to cool the gas to a definite selected temperatureindicated by thermometer 60. The removed entrained material and any condensate cooling leaves the scrubber with produced by the scrubbing and cooling liquid through connection Other means for removing entrainedr particles such as the use. of packing with or without v scrubbing mightbeemployed.

The' cleaned andl cooled gas sample passes through connection 02 to the relative density register 03. The pressure oi.v thegas may be controlled by valves to maintain a desired pressure approximating atmospheric and indicated by the manometer 04. 4

' The gas passes through Vthe relative density register 83, in which its density is compared with thatof air, which is drawn in through connection 85, by way of the drier 0B. The gas-sample and the comparison air leave the register by way of connections l1 and 80 respectively. The relative density register may be arranged to continuously indicate and record the density with respect to air of the producedv oil gas at chosen standard conditions of temperature and pressure. for example at 60 F'. and slightly above atmospheric Y pressure.

An example of a type oi' relative density register cracked in vpassage through the vapo'rizationl space Il, checkerbrick 25, vaporization space 32,

checkerbrick 26, and superheater checkerbrick 3B and 31, the resulting products of pyrolysis passing through oitake Il, to the wash box, the uncondensed gas passing through connection I6 as before. During its passage through connection 46, the gas may be sampled, scrubbed, cooled,

as before de- -tions during the run" produces a swing 'during the run" of' not more than 0.03'in density of the oil gasl when measured relative to air, at 60 F. and slightly above atmospheric pressure,`by

" 4the method above described or by anequivalent which may be advantageously `employedis that known commercially as RanarexP The relative density ot the gas, so determined,

' may be employed as a messina of the intensity of the pyrolysis effected in the severalv portions of .the muxo4 l l y l.

As the gas making "run proceeds, the temperature conditions in the vaporizing chamber 32 and in the checkerbrick 2l and the superheater are reduced due to the abstraction of heat for vaporization 'of the oil and for the cracking of the resulting vapors. This cooling is vreduced in rate, however, by the passage into the vaporisation chamber l2 of the 'steam admitted to the' combustion chamber 30, through steam supply 52 and superheated in passage through the combus-l tion chamber and the checkerbrick sections 2l and 25, while simultaneously cooling these' upstream portions of the path of stored heat.

After aconsiderable portion of thegas making' run haselapsed, i'or example after the expiration of 60, '.10 or 80% thereof at the end of which time pyrolysis conditions in the path ofA pyrolysis have been moderated somewhat due to cooling of that portion of the path of stored heat by the pyrolysis, and providing also that at the end of which time, the temperature conditions portion of the path of Istored heat upstream from the point of oil admission vhave been sumciently moderated by the passage of steam therethrough,

the admission or oilthrough supply means Il is terminated (steam supplied through 5l may also be shut off).

f During the succeeding portion of the run the path of lpyrolysis is extended upstream in the path ci' stored heat by supplying oil through oil supply means 1l to vaporizationv space Il. Steam may be continued to be supplied to the combustion space Il through steam supply 52,*and additions of the method. y

\ More preferably this` swing in relative density doels not exceed 0.02 and still more preferably 0.0

'I'hose skilled in the art will understand that care should be taken, in .comparing relative densities of the oil gas' produced in the several porruns, to avoid the inclusion oi signicant proportions of other gases such for example as unpurged combustion gases from the rolysis.

blow," or correction should be made therefor ino'rder tocalculate the swing in relative density which is due to changes in conditions of oil py- At the endfof the run the supply ci!l oil to vaporization space 3l, through oil supply meansV 10 is shut off, and the gas set is purged, for example, by continuing the admission of steam thereto through steam supply 52, purging .the pyrolysis products out of the set through ofitake The steam may then be shut oii! and the cycle 4 repeated.

' tions of the run 1n the It will be understood by those skilled in the art that the points of admission of oil and Aof steam in the respective portions of the runJ as well as the durations of the respective pormay beso chosen that the pyrolyzing effect of the shifted very closely approximatesv that of the original path ofpyrolysis at the outset of the run.

Within a very considerable" range ofvariation, the influence cf changes in temperature upon cracking intenslty'may beclosely compensated for by lappropriate changes in the length of the pvrolyzin'g path.

Under certain conditions, it may be possible to move the' pointof oil admission upstream in the path of stored heat, and simultaneously move upstream the point of exit of the pyrolysis products from the path of stored heat, maintaining the lengthof the 'path of pyrolysis substantially tional lsteam may be supplied simultaneously to the vaporization 4space Il, through steam supply means 1I. i

The oil lis vaporized and the resulting vapors the same as before, providing temperature conditions inthe-shifted path are appropriate.

For example in the later portion of the run,

the oil may be admitted to the vaporization space 3l, through supply 42 closed and valve. open, the products of pyrolysis are'tak'en of! from the superheater through l measure of how closely pyrolysis conpath of pyrolysis,

10, while with valves, 40 and` the t s asoasss particular method'of measuring temperature. Some of the influential variables are the character of the fuel and the method of combustion, the character; quantity and arrangement of the heat storage material, the character,

subdivision, and rate of input of the hydrocarbon y material pyrolyzed, the character and quantity of the diluent gas, whether or not the hydrocarbon material is vaporized as well as pyrolyzed by the stored heat, and the length and subdivision of the cycle.

In the operations particularly described in the foregoing, the path of pyrolysis was shifted within the pathA of stored heat but once during the run. Those skilled in the art will readily understand, that the path of pyrolysis may be so shifted a plurality of times, and that the manner of the shift need not be the same. For example the rst shift of thepath'of pyrolysis during the run may be made by shifting the point of removal of the products downstream in the path of f stored heat, without changing the point of oil admission, while the next shift may be made by moving the point of oil'admission upstream in the path of stored heat, without changing the point of .removal of the products.

Other modications of the process and of the apparatus illustrated will occur to those skilled in the art without departing from the spirit of the invention. For example, it .may be preferred, especially when heavy oilsA and residuums are employed, which yield particularly large ,quantitles of coke on vaporization, to further subdivide the gas set, so as to provide separate shells for the upstream and downstream vaporizing zones either or both of which may be devoid of vcheckerbrick below the point of `oil admission thereto. If the vessels are of large diameter, a central refractory -pier may be provided in each otherwise empty vaporizing chamber.

The set may be further subdivided for other reasons, or on the other hand may be consolidated into a single shell.l A

Although it is preferred to flow the fluid hydro-- carbon material through the path of stored heat in the direction of thefiow of the heating gases, as above described, the invention may be applied in cases in which these flows are in opposite directions to each other. l

From the foregoing, it will be obvious to those skilled in the art that the invention may be readily applied tol the manufacture of carburetted water gas. For example, during the first portionl of the up "run the carburetting oil may be admitted into the path of stored heat downstream water gases compared as to relative density, or the determined relative densities should be corrected for the presence of such combustion riod of the cycle refractoryheat storage material is heated by the passage of hot combustion gases in contact therewith to establish 'a path of stored heat and in .which in a uid hydrocarbon pyrolyzing period of the cycle fluid hydrocarbon material is passed in vapor phase along said path of stored heat in contact with said heated refractory heat storage material and cracked by said stored heat, the steps which comprise employing during a relatively early portion of said pyrolyzing period a part only of said path of stored heat as the path of pyrolysis; and during said pyrolyzing periodi after the moderation of pyrolyzing conditions obtaining in said part` of said path of stored heat shiftingv said path of pyrolysis longitudinally Within said path of stored heat insuch a manner that the intensity of pyrolysis effected during the succeeding portion of said pyrolyzing period by said shifted path of pyrolysis more closely approximates the in-yI tensity of pyrolysis effected-during said'relatively early portion of said pyrolyzing period .by said` part of said path of stored heat previously employed as the path of pyrolysis.

2. In a, cyclic process for hydrocarbon material in which a heating period of the cycle refractory lheat storage material is heated by thepassage of hot combustion gases in contact therewith to establish a path of stored Aheat and in which in a fluid hydrocarbon pyrolyzs ing period of the cycle fluid hydrocarbonfmaterial is passed inv vapor phase along said path of stored heat in contact with said heated refrac- Y tory heat storage material and cracked lby said stored heat, the steps of improving` the uniformity of cracking during saidl pyrolyzing period which' comprise initially during said'pyrolyzing from the topyof the carburetter, and during a later portion of the up run the admission of the oil may be to the top of th carburetter, the carburetted water gas in each case being led from the set at the top .of the superheater.

In comparing the relative densities of the carburretted water gas produced during different portions of the run, it should be remembered that the composition of the blue water gas component of the carburetted water gas varies with the temperature of the fuel bed, and that this affects the density of the carburetted water gas. Those skilled in the art will understand how to correct y for varying blue water 'gas composition and will be able to employ the corrected relative gas density vto control the uniform pyrolysis of the carburetting oil.

As in the case of oil gas manufacture, signincant quantities of combustion products from the "blow should be excluded from the carburetted period cracking said hydrocarbon material in vapor phase in only a part of said path of stored heat; and in a later portion of said pyrolyzing period after the intensity of cracking effected by said part of said path of stored heat has .diminished due to cooling, increasing the length of the part of the path of stored heat employed for cracking in such a manner as to compensate for said cooling sumciently to substantially restore the intensityI of cracking initially obtaining in the original path of pyrolysis.

3. In a cyclic' process for the pyrolysis of fluid hydrocarbon material with the .production of gas in which ina heating period of the cycle refractory heat storage material is heated by the p 'assage of hot combustion gases in contact therewith to establish a path of stored heat and in which-in a fluid hydrocarbon pyrolyzing period of the cycle iiuid hydrocarbon material is passed in vapor phase along said path of stored heat in contact with said heated .refractory heat storage material and cracked by said stored heat, the steps comprising employing during a relatively the invention tothe reformthe pyrolysis of fluid to increase the intensity of cracking effected therein as compared with said lessened intensity of cracking, and during the succeeding and relatively later portion of said pyrolyzing period employing for cracking said lengthened path of pyrolysis;` and conducting said pyrolysis in a manor to mantain in said respective pyrolyzing portions of said path of stored heat during hydrocarbon pyroiysis therein pyrolyzing conditions such that change in intensity ci cracking during said pyrolysing period produces a swing during said pyrolysing period of not more than 0.03 in the density ci the sas resulting from said hydrocarbon pyrolysis when measured reiative to air at approximately 66 F. and slightly above atmosv pheric pressure.

f d. in a cyciic process for the pyrolysis of duid hydrocarbon material with the production of sas in which in a heating period of the cycle reirsetory heat storage material is heated by the pas'- sage of het combustion gases in contact therewith to establish a path of stored heat and in which in a iiuid hydrocarbon pyrolyzing period of the cycle uid hydrocarbon material is passed in vapor phase along said path of stored heat in contact with said heated refractory heat storage' material and cracked by said stored heat, the

` steps which comprise during a. relatively early portion of said pyrolyzing period admitting huid hydrocarbon to a downstream 'portion of said path of stored heat and cracking said fluid hydrocarbon material therein in vapor phase .while simutaneously cooling an upstream portion of said path of stored heat by the passage of a diluent gas therethroughv said diluent sas being passed therefrom into said downstream portion of said path oi'l stored heat and therethrough together with said hydrocarbon material undergoing cracking therein; and after the cooling of said upstream portion of said path of stored heat by the passage therethroughof said diluent gas and after 'the cooling of said downstream portion of said path of stored heat by the pyrolysis carried on therein, lengthening the path of pyrolysis by shifting the admission ofsaid hydrocarbon fluid material to a point removed upstream from the point oi previous admission thereof, and thereafter during a, relatively later portion of said pyrolyzing period pyrolyzing' said fluid hydrocarbon material by passage through the lengthened path of pyrolysis in `the presence of diluent gas also passed therethrough; and conducting said pyrolysis in a manner to maintain in said respective pyrolyzing portions of said-path of st ored heat during hydrocarbon pyrolysis therein pyrolyzing conditions such that change in intensity of cracking during said pyrolyzing period produces a swing during s aid pyrolyzing periodof not more than 0.03 in the density of the gas resulting from said hydrocarbon pyrolysis when measured relativey to air at approximately 60 F. and slightly above atmospheric pressure.

hydrocarbon material in which in a heating ricci of the cycie refractory heat'storage material is heated by the combustion o duid fuel and the passage of the resulting hot combustion gases in contact therewith to establish a path of stored heat and in which in afluid hydrocarbon pyrolysing period of the cycle iiuid hydrocarbon material is passed in vapor phase along said path of stored heat in contact with Fsaid heated refractory heat storage material and cracked by said stored heat, the steps which comprise during a relatively early portion of said pyrolyzing period introducing uid hydrocarbon material to said path of stored heat at a point removed downstream from the upstream end thereof and pyrolyzing said fluid hydrocarbon material in vapor phase by passage downstream through said path of stored heat inthe presence of steam heated ine. portion of said path of stored heat removed upstream from said pointI of introduction or said iiuid hydrocarbon material; after the cooling of said upstream portion of the path of stored heat by the passage of steam therethrough and after a diminishing of the cracking intensity obtainingin the downstream portion of the path of stored heat empioyed for pyrolysis, increasingvthe length of the path of pyrolysis by changing the point of admission of hydrocarbon material to a point removed upstre in the 'path of stored heat from the point of previous l admission; and thereafter in the succeeding and relatively later portion of the pyrolyzing period pyrolyzing said duid hydrocarbon material by passage in the presence of steam through said lengthened path of pyrolysis; the intensities of the cracking produced in the respective portions oi the pyrolyzing period being closely similar.

lo". In a cyclic process for the pyrolysis of fluid hydrocarbon material with the production of gas in whichin a heating period of the cycle refractory heat storage material is heated by the combustion of iiuid fuel and the passage of the resulting hot combustion gases vin contact therewith to establish a path of stored heat and in which in a of said pyrolyzing period'introducing fluid hydrocarbon material to said path of stored heat at a point downstream from the upstream end thereof cracking said hydrocarbon material by passing said material downstream through said path of stored heat in the presence of steam introduced to said path of stored heat at a point upstream from the point of introduction ,of said hydrocar- 'bon material, removing products oi?y pyrolysis and steam from the path oi stored heat at a point upstream from the downstream end thereof i after the cooling by said cracking of the portion of the path of stored heatI employed for pyrolysis,

' lmoving downstream in said-path of vstored heat 5. In a cyclic process for the pyrolysis of iiuid 'l the point of removal therefrom of said products of pyrolysis and steam to increase the length of the path of pyrolysis, and during the succeeding portion of said pyrolysis period cracking said hydrocarbon material by passage with steam through saldlengthened path of pyrolysis: and conducting said pyrolysis in a manner to maintain in said respective pyrolyzing portions oi' said path of stored heat during hydrocarbon pyrolysis therein pyrolyzing 'conditions sjuch that change ZOnB arranged 3,393,333 v a h '1. In a cyclic process for the pyrolysis of petroleum oil in which in a heating period of the cycle refractory heat storage material is heated by the combustion of huid fuel and the passage of the resulting vhot combustion gases in contactthereing in said upstream portionof said pathof stored heat .by said passage of steam therethrougnshift.-

ing the introduction of vsaid vapor phase p'etro7 leum oil to said previously cooled upstream portion of said path ofl stored heat therebylengthening the path of pyrolysis employed during the lsucceeding portions of the pyrolyzing period; said with to establish a path of stored heatand'in which in a petroleum oil pyrolyzing period of the cycle petroleum oil is introduced into said path of stored heat for vaporization and for the crack-` ing of the resulting vapors in contact with said heated refractoryheat storage material, the steps o of improving the uniformity of the cracking of the petroleum oil which comprise introducing petroleum oil during a relatively early portion of said oil pyrolyzing period into an oil vaporizing in a portion of said path of stored heat downstream from the upstream end thereof in the presence of steam introduced into said path of stored heat at a point upstream from said oil vaporizing zone; passing the resulting oil vapors together with said steam downstream through said path of vstored heat for cracking therein; after the cooling of the downstream portion of said path of stored heat employed as the path of pyrolysis and after the cooling of the portion ci said path of stored heat, upstream from said vaporization zone by the passage of said steam therethrough moving the point of oil admission c upstream inthe path of stored heat to a second vaporizing zone and thereby increasing the length of the path of pyrolysis within said path of stored heat; and during the succeedinglportion ofv oil pyrolyzing period vaporizing petroleum oil in said second vaporizing zone in the presence of steam, and passing the resulting oil vapors therewith through said lengthened path of pyrolysis for cracking therein; the increased length of said path of pyrolysis during said succeeding portion of said pyrolyzlng period suillciently compensating for reduced temperature conditions therein to effect an intensity of cracking at the beginning of said succeeding portion closely approximating that originally effected at the beginning of said pyrolyzing period'.

8. In a cyclic process for the pyrolysis of petroleum oil in which in a heating period of the cycle refractory heat storage material is'heated by the combustionof uid fuel and the passage of the resulting hot combustion gases in contact therewith to establish a path of stored heat and in which in a petroleum oil pyrolvzing period of the cycle petroleum oil is passed in vapor phase along said path of stored heatin contact with said heated refractory heat storage material and cracked by said stored heat, the steps which comprise during a relatively early portion of said oil pyrolyzing period introducing petroleum oil in vapor phase to said path of stored heat at a point downstream from the upstream end thereof;

passing said petroleum oil in vapor phase downstream through said path Iof stored heat for cracking -therein together` with steam, said steam being passed into said portion of the path of stored heat employed as the path of pyrolysis after having been superheated by passage through a portion of said path of stored heat upstream therefrom; after the cooling eilect of said cracking has diminished the intensity of cracking occurring in Said path of pyrolysis and after the moderation of the temperature conditions previously obtain' increase in the length of said path of pyrolysis compensating sufficiently for reduced temperature conditions therein to effect an intensity of cracking at the start of said succeeding portionl of said pyrolyzing period closely approximating that initially effected in said earlyl portion of said Dyrolyzing period. y

9. In a cyclic process for` the pyrolysis of fluid hydrocarbon materialin which in a heating period of the cycle refractory heat storage material is heated by the passage of hot combustion gases in contact therewith to establish a path of stored heat branched in anv upstream portion thereof and in which in a fluid hydrocarbon pyrolyzing period of the cycle fluid hydrocarbon material is passed in vapor phase along' said path -of stored heat in contact with said heated refractory heat storage material and cracked by said stored heat, the steps which comprise during a relatively early portion of said pyrolyzing period introducing uid hydrocarbon material to said path of stored heat at a point downstream from the upstream end thereof, passing said uid hydrocarbon material downstream in said path of stored heat for pyrolysis therein in the presence of steam introsaid f duced'to said path of stored heat at a point upstream from said point of introduction of fluid hydrocarbon material, said steam in vits passage through the'upstream portion of said path of stored heat cooling said upstream portion and carrying heat into the downstream portion which is being cooled by said pyrolysis; thereafter terminating said downstream introduction of said fluid hydrocarbon material and introducing steam and fluid hydrocarbon material to one branch of said path of stored heat upstream fromy said previous point of introduction of said fiuid hydrocarbon material andpassing said steam and iluid hydrocarbon material downstream through said path of stored heat to effect the pyrolysis of said fluid hydrocarbon material; and simultaneously with said last recited step, passing steam downstream through another branch of said upstream portion of said path of stored 4heat for downstream union with the flow of steam and-hydrocarbon material issuing from said first mentioned branch of the path of stored heat; the temperature conditions and now of materials being so controlled and the lengths of the paths' of pyrolysis so selected as to closely approximate the y cracking intensities effected in the respective porby the combustion of fluid fuel and the passagetions of the pyrolyzing period. n

l0.' In a'cyclic process for the pyrolysis of petroleum oil in which in a heatingperiod of the cycle refractory heat storage material is heated of the resulting hot combustion gases in contact -therewith to establish la path of stored heat and in which in a petroleum oil pyrolyzing period of the cycle petroleum oil is passed in vapor phase along said path of stored heat in contact 7 with said heated refractory heat storage material and cracked by said stored heat, the steps comprising during a relatively'early portion of said pyrolyzing period spraying petroleum oil into a vaporizing zone arranged in said path of stored heat downstream from the combustion zone end thereof, vaporizingsaid petroleum oil tion of the path of stored heat upstream from said vaporizing zone and thence into said vaporizing zone, passing said steam and the resulting oil vapors downstream through said path of stored heat for the pyrolysis of said vapors therein; thereafter during a relatively later portion of said pyrolyzing period spraying petroleum oil into a second vaporizing zone arranged in the path of stored heat upstream from said first mentioned vaporizing zone, vaporizing said petroleum oil in said second vaporization zone in the presence of steam, passing the resulting vapors downstream through the path of stored heat from said second vaporizing zone with said steam for pyrolysis therein, and removing the resulting products of pyrolysis and steam from the path of stored heat at a point upstream'from the point of removal during said earlier portion of said pyrolizing period; the temperature conditions and ows of materials being so controlled andthe lengths of the paths of pyrolysis so selected as to closely approximate in the later portion of the period o pyrolysis, the cracking intensity obtaining in the earlier portion of the period of pyrolysis.

11. In a cyclic process for the pyrolysis of fluid hydrocabron material with the production of gas in which in a heating period of the cycle refractory heat storage material is heated by the passage of hot combustion gases in contact therewith to establish a path of stored heat and in Which in a fluid hydrocarbon pyrolyzing period of the cycle iluid hydrocarbon material is passed in vapor phase along said path of stored heat in contact with said heated refractory heat storage material and cracked by said stored heat, the steps which comprise employing during a relatively early portion of said pyrolyzing period a part only of said path of stored heat as the path' of pyrolysis; during said pyrolyzing period after the moderation of pyrolyzing conditions obtainingA in said part of said path of stored heat shifting said path of pyrolysis longitudinally within said path of stored heat in sucli a manner as to increase the intensity of pyrolysis; and conducting said pyrolysis in a manner to maintain in said :respective pyrolyzing portions of said path of stored heat during hydrocarbon pyrolysis therein pyrolyzing conditions such that change in intensity of cracking during said pyrolyzing period produces a swing yduring said pyrolyzing period of not more than 0.03 in the density of the gas resulting from said hydrocarbon pyrolysis when measured relative to air at approximately F. and slightly above atmospheric pressure.

12. In a cyclic process for the pyrolysis o! petroleum oil in which in a heating period of the cycle refractory heat-storage material is heated by thepassage of hot combustion gases in contact therewith to establish a path of stored heat and in which in a petroleum oil pyrolyzing period of the cycle petroleum oil is introduced into said path of stored heat for vaporization and for the cracking of the resulting vapors in contact with said heated refractory heat storage material with the production of gas, thesteps of improving the uniformity ofthe cracking of the petroleum oil which comprise introducing petroleum oil during with said steam downstream through said path of stored heat for cracking therein; after the cooling of the downstream portion of said path of stored heat employed as the path of pyrolysis and after the cooling of the portion of said path of stored heat upstream from said vaporization zone by the passage of said steam therethrough moving the point of oil admission upstream in the path of stored heat to a second vaporizing zone and thereby increasing the length of the path of pyrolysiswithin said path of stored heat; during the succeeding portion of said oil pyrolyzing periodvaporizing petroleum oil in said second vaporizing zone in the presence of steam, and passing the resulting oil vapors therewith through said lengthened path of pyrolysis for cracking therein; and conducting said pyrolysis in a manner to maintain in said respective pyrolyzing portions o1 said path of stored heat during hydrocarbon pyrolysis CHARLES GORDON MILBOURNE.

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