US2605176A

US2605176A - Manufacture of combustible gas

Info

Publication number: US2605176A
Application number: US113765A
Authority: US
Inventors: Harry B Pearson
Original assignee: Allied Chemical and Dye Corp
Current assignee: Allied Corp
Priority date: 1949-09-02
Filing date: 1949-09-02
Publication date: 1952-07-29
Anticipated expiration: 1969-07-29
Also published as: BE497277A; DE847945C; FR1022014A

Description

' Jqly 29, 1952 H. B. PEARSON MANUFACTURE OF COMBUSTIBLE GAS Filed Sept. 2, 1949 VALVE STACK MAKE GAS MAKE GAS I IIPR/MAR Y AIR" I5 l6 H SECONDARY 53 52 o AIR 3/ l9 1/ fi HEATOIL H STEAM 32 28 27 26 59 MAKE REACT/0N OIL 57 REACT/0N CHAMBER 22 CHAMBER 3 24 3 l 1 c/zossovs/a 2/ I I 49 I 20 $129: 56:: B \Q o::e:.\\\ 5O HYDROCARBON FIXING FIXING 7 HYDROCARBON CARRIER 5 CHAMBEIZ CHAMBER No.2 SET CARR/ER GAS 4- R 7/ 72 73 INVENTOR.

e8 57 66 HARRY B. PEARSON ATTORNEY.

Patented July 29', 1952 MANUFACTURE OF COMBUSTIBLE GAS Harry B. Pearson, New York, N. Y., assignor to Allied Chemical & Dye Corporation, New York,- N. Y., a corporation of New York Application September 2, 1949, Serial No. 113,765

9 Claims.

1 This invention relates to the manufacture of fuel gas from hydrocarbons and. more particularly refers to a new and. improved process and apparatus for converting normally liquid hydrocarbon oils and condensible hydrocarbon gases referred to in the industry as L. P. gas or liquidpetroleum gas which gases include propane, butane and pentane into a highly combustible homogeneous gas of'a quality adapted to be principally used for heating.

In my cofiled United States application filed September 2, 1949, Serial No. 113,766, I have described an essentially unidirectional flow operation involving three primary zones to effect pyrolytic decomposition of hydrocarbon charging stock into combustible gas. The present invention is directed to a four-zone reverse directional fiow system for the production of combustible gas from fluid hydrocarbon charging materials.

The discovery of increasing sources of natural gas in the Mid-west, South-central and Southwest parts of the United States together with improved technique in the fabrication of large size, high pressure steel pipe, and in the protective coatings to be applied thereto, has increased the distance from the producing wells that such gas may be economically transported. However, the cost of construction is of great magnitude, because of the'vast distances involved which precludes the construction of parallel lines which might be utilized to avert cessation of delivery, in the case of pipeline failure, or to augment the normal capacity of the lines in the case of abnormal demand during extremely inclement weather conditions in the winter which is the peakdemand period in most sections of the 7 country for which this service is intended.

For many years the gas utilities in New England and the North Atlantic states have supplied their customers with heating and cooking g'as, either from coal gas retorts, lay-product coke ovens or carburetted water gas" plants, either separately, or mixed'with one another, or with other types of manufactured gas such as blue water gas, or producer gas and L. P. gas. These I sources of gas supply have generally been found quate in amount to meet peak load and oftentoo highin cost.

' Attempts havebeen made to convert oil into. the desired fuel gas without significant commercial success for reasons which may be better understood by a review of "some-- of the requirements of the gas industry with respect to oil gas 7 manufacture. Gas manufactured from oil whether the primary source of supply or the supplemental means of insuring the consumers fuel gas demands should desirably be of uniform quality with the proper combustion characteristics. An oil gas process should be elastic-i. e. capable of quickly, continuously producing gas from hydrocarbon oil and conversely shut down in a simple expeditious manner. The oil cracking apparatus should be flexible particularly in its ability to treat less costly fractions of petroleum oils such as low gravity gas oils or heavy residuums and also in its capability of changing the properties of the gas product within reasonable limits and its rate of production without seriously impairing the operation. Since price is a dominant factor controlling the sale of fuel gas over other competitive fuels all elements entering into the cost of the gas such as investment cost, value of charging stock, operating cost, maintenance and yield are of paramount importance to the manufacturer. In view of the high volume of gases consumed, small differentials in price per 1000 cu. ft. of heating gas which may appear insignificant, when multiplied by the total output of the gas in millions of cu. ft. assume substantial proportions in dollars. Furthermore, oil cracking machines should not only be simple and efiicient in operation but also compact in design.

The quality of a heating gas is, of course, governed by the consumers" requirements. The greatest number of customers of gas burn gas in atmospheric gas burners fixed in the sense of having orifices of a definite size and air shutters open to a predetermined extent which cannot conveniently be changed thereby imposing on the gas producer the necessity for maintaining a uniform quality of gas. Other important considerations in the efiicient operation of atmospheric burnersare the properties'of the gas, particularly the calorific value and density of the gas. Desirably a gas should have a B. t. u. per cu. ft. in excess of about 890 and generally above 950 and a specific gravity (air=1) between about 0.6 and 0.8, preferably about 0.68, anoil gas having these characteristics being hereinafter designated as high B. t. u. low gravity gas. The density of a gas is influenced to alar egdegree by its content of hydrogen and illuminants, i. e. hydrocarbons of higher molecular weight. Gases containing too large a volume of hydrogen tend to flashback and gases haVingQtoo large a percentage of illuminant's give anl'elongated flame. To my knowledge none of the prior art oil cracking de- -vices'has succeeded.fin coinmercially producing high B. t. u. low gravity gas.

a gas producing process utilizing low grade 7 petroleum oils as raw charging stock with the elimination of by-product residual carbonaceous material or free carbon and with improved therin operation.

A further object of the invention is to provide an oil gas apparatus simple in construction, compact in design, and durable, certain and efficient in operation.

A still further object of this invention is to provide an improved process and apparatus for decomposing hydrocarbon oils into gas which is economical, elastic and flexible in operation.

Further objects and advantages will be apparent from the description and accompanying drawing. V

Apparatus for carrying .out the conversion .of oil into gas in accordance with :the. present invention involves a novel combination and arrangement .of elements including two vertical refractory lined duplicate vessels connected at their tops by asgasrchannel, each vessel constructed to provide an empty chamber above another chamber at least partially filled with checkerbrick or refractory material with voids therebetween to permit the passage of gas therethrough and divided therefrom by a refractory circular orifice, two vertical refractory lined riser pipes'extending upwardly :to a height above the vessels with each riser pipe connected to the base of a refractory ifilled chamber, a stack valve fitted to the top of ..each riser pipe, conduits leading from .the top .of each ,riser pipe :connected to a three-way valve for reversal of flow in the apparatus and for the release of make gas, an inlet for the introduction :of primary air into each riser pipe, a steam conduit leading into each riser pipe, .a gas inlet for the introduction of hydrocarbon carrier gas into thebase of each'refractory filled chamber, .s'econdary air inlets leadinginto "each empty chamber, a downwardly directed .spray nozzle near the top of each empty chamber for the dispersion of make oil and a heat oil inlet disposed near the bottom of each empty chamber.

4 carrier gas into the second zone and simultaneously injecting hydrocarbon chargingystock into the second zone countercurrent to the upward flow of steam and'hydrocarbon' carrier gas maintained at a velocity suiiiciently high to prevent passage of carbonaceous material downwardly out of the second zone, withdrawing gaseous constituents substantially free from solid and liquid carbonaceous materials from the top of the second zone, directing them downwardly through the third and fourth zones thereby fixing the gases, and discharging the gaseous constituents from the fourth zone; a

reverse flow of air as described above; and a reverse fiow of steam and hydrocarbon carrier gas as described above.

, plete cycle of operation comprises, (a) a blast lhe operation .ofemy process involves passing 7 air upwardly through a first zone at least partially filled with heated refractory material with voids therebetween'to permit the passage,

, thence passing the combustion gases downwardly through a fourth zone at least partially filled with refractory material with voids therebetween to permit the "passage, of gas'there through thereby transferring heat from the combustion gases to therefractory material, and discharging the combustion gas from the fourth zone; passing a hydrocarbon carrier gas and steam upwardly through" thefirst zone, intro ducing the mixturexof steam andihydrocarborl period wherein air passes downwardly through a riser pipe connected to the base of a first vessel, upwardly through checkerbrick contained in'the bottom chamber of "thefirst vessel thereby preheating the air, thence discharging the preheated air from the top of the bottom'chamber containing checkerbrick through anorifice into an empty chamber disposed above the bottom chamber wherein secondary air is admitted and heating oil'is introduced, which lat ter burns thus imparting heat to the'walls of the first empty chamber, then directing the combustion gases through'a. gas channel to the top of a second, empty chamber in'a second vessel, downwardly through the second empty chamber thereby transferring heat from the combustion gases to its walls and burning any carbonaceous deposits thereon 'by means 'of excess secondary air, continuing the passage of combustion gases from the bottom of the second empty chamber through an orifice downwardly through a second bottomchamber containing checkerbrick disposed' beneath the second empty chamber thereby heating the -checkerbrick therein, and then discharging the combustion gases to the atmosphere through a second riser pipe leading from the-base of the second bottom chamber; (1)) apurge period for the evacuation of combustion gases contained in the system wherein steam introduced into the first riser pipe passes upwardly through the first vessel, downwardly through the second vessel, and discharges to the atmosphere throu h the second riser pipe; (0) a make period wherein steam and a hydrocarbon carrier gas introduced into the first riser pipe pass upwardly through the checkerbrick of the first bottom chamber,

thence discharging through an orifice upwardlyv into the first empty chamber -countercurrent to downwardly sprayed make oil, maintaining the velocity of the mixture of steam and hydrocarbon carrier gas suflicientlyzhigh to prevent .passage of oil vapors and carbon tothe chamber beneath the, orifice, withdrawing gaseous constituents substantially free of 7 solid carbonaceous material andliquid oil from thetop of the first empty chamber through a gas channel into the top of a second emptychamber, then passing the gaseous constituents downwardly through the second empty chamber, the second:

orifice and the second bottom chamber thereby fixing the gas, and discharging the gaseous con stituentsfrom the bottomof the second bottom chamber through theisecond-riser pipe; (00- a second purge period forthe displacementof gaseous constituentsin the system' 'whereby steam introduced into thefirst'riser pipe passes V tion on any particulartheory or mechanism of reaction the following explanation may aid in a better understanding of the process and its attendant advantages over the prior art.

The formation of carbon and carbonaceous materials are an inevitable by-product result ing from the pyrolytic decomposition of hydrocarbons, particularly residual oils, into gas. These carbonaceous deposits have a detrimental effect on oil-gas cracking operations in several respects, among whichare loss in yield of fuel gas product, plugging of apparatus, decreased efficiency of operation and rapid deterioration of apparatus. In the operation in accordance with the present invention the bulk of the carbonaceous material resulting from the conversion of the oil into gas is confined within an empty chamber out of the path of the checkerbrick section in the apparatus and only oil vapors and gases substantially free from solid carbonaceous materials and liquid oils are subjected to a fixing operation'in the checkerbrick section. This I accomplish by first heating the empty chamber to a peak cracking temperature of the system and then injecting hydrocarbon oil into the heated empty chamber countercurrent to an upward flow of a mixture of steam and hydrocarbon carrier gas introduced into the bottom of the empty chamber at a velocity high enough to prevent the oil and carbonaceous materials from flowing down through the chamber. The combination of upwardly flowing steam and hydrocarbon gas and peak temperature in the empty chamber causes vaporization and cracking of the liquid oil with concomitant production of carbon and carbonaceous material which deposit on the walls of the empty chamber leaving effluent vapors and gas substantially free from solid carbonaceous material and liquid oil for'further conversion, i. e. fixing, in a separate zone. Confining the bulk of the carbonaceous material to the walls of an empty chamber is beneficial in that the flow of materials through the apparatus is not materially impeded, thus maintaining high throughput as well as reducing shut-downs for cleaning. Furthermore, avoidance of material deposition of carbonaceous material on the checkerbrick eliminates rapid deterioration of the brickwork which normally requires frequent replacement, due, it is believed, to thermal shock resulting from direct impingement of the carbon on the checkerbrick and the burning of the carbon from g the checkerbrick causing localized hot spots.

The addition of a hydrocarbon carrier gas to the steam during the make period has manifold advantages. It supplements the steam as a propelling agent for carryingthe oil vapors through the apparatus. It aids "inqpreventing oilv and carbonaceous material from dropping 'down through the bottom of the empty chamber. It

facilitates vaporization of the oil and better distribution of the oil vapors undergoing further cracking, and in addition permits the use of a smaller amount of steam during the make period, the advantage of which is reflected in lower cost of steam and more intensive cracking conditions 40 zone and a zone filled with refractories.

6. with increased capacity. The replacement of a. portion of the steamwith a hydrocarbon car-- rier gas during the make period has the effect of maintaining a higher temperature in the 5 cracking zone for the reason that the heat requirements for steam including its endothermic heat of reaction under the conditions of operation are appreciably higher than the heat requirements of the hydrocarbon carrier gas, consequently the steam extracts a greater amount of heat from the equipment and lowers its temperature to a greater degree than an equivalent volume of carrier gas. Since cracking is a function of temperature, pyrolytic conversion of the oil 7 into gas proceeds at a much more rapid rate when hydrocarbon gas replaces steam as the propelling medium. Of course the use of some steam is desirable for the purpose of converting the carbonaceous deposits into blue gas. The use 0 of recycle make gas as the hydrocarbon carrier gas has the further important advantage of degrading the higher molecular weight hydrocarbon gases thus reducing the percentage of illuminants in the final gas and lowering its specific gravity.

with localized hot spots therein. As a result,

,portions of the oil are overcracked with the deposition of excess carbon and other portions of the oil are undercracked with incomplete uti lization of the oil. I have discovered that more favorable temperature conditions in the cracking zone may be attained by blasting upwardly through an empty reaction zone to a peak gas making temperature and then passing combustion gases downwardly through another empty The downward flow of gases through the empty reaction zone and checkerbrick section of the fix ing zone gives a relatively even downward temperature gradient following the path of combustion gases and a more uniform heat distribution throughout the checkerbrick section. The introduction of a hydrocarbon carrier gas during the make period has the cumulative effect of better distribution of the oil thereby also mini- 5O mizing overcracking and undercracking.

The particular arrangement of apparatus and method of operation as taught herein results in more eifective utilization of the equipment for carrying out cracking in that the greater part of the equipment is maintained under cracking conditions and utilized for elfecting the conversion of oil into gas, the remaining portion of the equipment serving to conserve heat by preheating the steam and air entering the system. It

will be observed that these eificient cracking con- "ditions are maintained regardless of the direction of flow of fluids in the system.

' Theintroduction of a hydrocarbon carrier gas during the make period of the operation provides a simple convenient method of. imparting flexibility to the operation merely by changing the V amount of hydrocarbon carrier gas.

As will be evident from the preceding discussion the various. operating principles incorporated in my process not only have individual beneficial effects but also cooperate with one another to product cummulative advantages.

The accompanying drawing is a diagrammatic fiow sheet illustrating the apparatus and process of the present invention.

terials 3 which refractoryJining absorbs heat and also protects the metal shell 2 which sur rounds it from the direct impact of hot gases. As an added protective measure, insulation may be interposcdbetween shell 2 and refractory lin ing Vessel I is divided'into two sectiona'an empty upper reaction chamber i'and a lower preheating or fixing chamber 5 filled with a refractory material 6 wherein will be retained and stored up surplus heat and which will give up heat. Dividing reaction chamber i and fixing chamber 5 is a circular orifice lwhich has the function of effecting thorough' mixing of the gases and also imparting a high velocity to the gas entering the bottom of chambers, A refractory lined conduit 8 connects the bottom of vessel 1 with the bottom of refractory lined riser pipe 8 which extends upwardly to a height, suitable to carry the blast gases above other equipment and to provide draught when the set is. shut down. A stack valve I l is fitted to the top of riser pipe 9 and disposed above it is stack 12. Make gas discharges from the top of riser pipe 9 through line i3 connected to a conventional three-way reversing valve l4. Primary air introduced for example by a blower, not shown in the drawing, enters,

conduit l5 passing through line -16, valve H and line [3 into riser pipe 9 or, if desired, the primary air may be blown directly into; riser pipe 9. Steam may be introduced into riser pipe 9 through line I8 and valve 19. Hydrocarbon carrier gas from an external source joins the flow of steam entering through line 65, valve -29 and entrance 2!, preferably disposed at the. bottom of riser pipe 9 V In, the preferred method of operation recycle make gas is returned as thecarrier agent to the bottom of preheating chamber-5 through line 56,

valve 61, exhauster ,68; valve Zdan'd inlet 2 5. Make oil is fed throughlines 2 2, 23, valve 24 and sprayed downwardly'by means of nozzle 25, of conventional design; counter-current to the upward flow of gases in reaction chamber 5. Heat oil passes through

line

26, 21, valve 23 into reaction chamber 4 through nozzle 29. Secondary air supplied by'a suitable blower, not shown inthe drawing, flows through conduit SI, 32, valve 33 into reaction chamber 4. Gases enter or leave the top of vessel I through refractory lined crossover or gas channel 3'4. I

Although not a preferred method of operation, the introduction of a'carrier gas-may be dispcnsed with entirely and'steam in the absence of event no make gas would be recycled or make gas returned only during a part of the make time.

No. 2 set and No. 1 set are substantially duplicates, the corresponding elements of set No. 2 bearing the following numerals: Vessel 35, metal shell 36, refractory lining 3?, reaction chamber 38, fixing chamber 3Q,.checkerbrick 3i, orifice 42, riser pipe 43, connecting conduit 4 stack valve G5, stack 46, steam inlet and valve ii? and 38, respectively, hydrocarbon carrier gas inlet and

valve

49 and 50, hydrocarbon carrier gas con duit from an external source 653, recycle line, valve, exhauster I I, 12 and i3, respectively, primary air inlet and valve 52 and 55, respectively, secondary air inlet and valve 54 and 55, respectively, make oil line, valve and nozzle 5? and 53, respectively, heat oil line, valve and nozzle v59, 6| and 62, respectively.

A complete cycle of operation in accordance with the present invention may be divided into four primary periods-a blast period,;a make gas period, a reverse blast period and a reverse make period with purges between the primary periods.

Preparatory to conducting the blast period, stack valve H is closed, stack valve 451s, open and reversin valve it is set against No. 1 set. Primary air is admitted through lines l5, l6,

valve ll, line I3 into the top of riser pipe 9 passcarrier gas employed as the propelling medium For example, during. theifi'rst, part of a make period the quantity of make gas produced may be so small as to make it difficult to recycle make gas at the initialstag'e of the make period and therefore the return of make gas may desirably'be dew layed for, by way of illustration, the first 30. sec-- onds. Also, due to special circumstances an operator may wish to limit the degradation of make gas normally accomplished by recycling in which.

brick section A]. 70.

A! and out through riser pipe '43.

ing downwardly therethrough through conduit 8 thereby partially preheating the air by its contact with the refractory lining before entering the bottom of chamber 5. The partially preheated air passes upwardly through checkerbrick 6 thereby becoming heated to a higher temperature by refractory 8 and also burns any slightamount of carbon whichmay be deposited thereon. The highly preheated air flows through orifice i into empty chambers wherein secondary air enters by way of

lines

34, 32 and valve 33. Heat oil pumped through lines 25, 2'5 and valve 28 discharges through, nozzle into the atmosphere of air whereupon the oil ignites, generating heat which is imparted to the walls of chamber 4. The quantity of. air supplied'should desirably be greater than that required for complete combustion of the heat oil, thereby pro viding an excess of air for burning any carbonaceous depositsfrom'the walls of chamber 4 made during a previousmake period. Com: bustion gases together with highly heated. secondary air pass'through crossover 35 downwardly throughempty chamber 38 heating its Walls and burning carbon thereon. Thus, carbonaceous deposits unconverted into blue gas during the make period are utilized for heating the reaction chambers, efiecting a saving in heat oil consumed and in some instances eliminating the need for heat oil.v The resultant combustion gases pass through orifice. downwardly through fixing chamber '39, heating oh-eckerbrick -As-ai result of blasting, the refractories in reaction chambers '4 and 38 and fixing chamber 39 attain suitable gas-making temperatures; preferably between downward temperature gradient following the path of the combustion gases and a more uniform heat'distribution throughout the checker- I attribute the more. uniform temperature conditions .due' to the. particular upward and downward passage of the .hot combustionygases in the chambers. Another iinpor tantfactor in my procedure of blasting is the maintenance of the highest temperatures :in

empty zonesto effect complete vaporization of 9 the oil and deposition of carbon inherentin the pyrolytic decomposition of oil on the walls of the empty chambers prior' to passage of the gaseous constituents through the fixing chamber thereby avoiding clogging or plugging of the checkerbrick section. I have also discovered that by maintaining the highest temperatures in the empty chambers 4 and 38 with lower more uniform temperatures in checkerbrick sections 6 and 4! I materially reduce spalling of the checkerbrick sections commonly caused by intense heat, sharp temperature differentials therein and flame temperatures caused by burning of heavy deposits of carbon thereon.

In order to avoid diluting the product gas with inert combustion gases contained in the cavity of the'system following the blast period, I prefer to purge the system preliminary to carrying out the make period. The combustion gases may be conveniently blown outby blowing with steam entering the top of riser pipe 9 through line l8 and valve [9 and discharging the gases from the top of riser pipe 43. At the end of the blast and purge periods valves 28, ll, 33 and 45 are closed. I

It is important to carry out the make period, that'is the gasification of the oil following the blast period, in the same directional flow as the blast'period. At the start of the make period on No. 1 set, steam valve [9 is opened, make oil valve 24 is opened and exhauster l3 put in operation for the return of recycle gas through inlet at 2|. Steam introduced at the top of the riser pipe 9 passes downwardly through the same and with recycle gas entering 2| moves upwardly through checkerbrick section 6 of chamber where it is highly superheated and expanded. The mixture of superheated steam and recycle gas discharges through orifice I at a high velocity and meets a downward hollow cone of sprayed oil ejected through nozzle 25. Alinear velocity of the mixture of steam and gas of about 50' feet per second will for most conditions of operation be found satisfactory. vaporization of the oil occurs almost instantaneously in the empty space of reaction chamber 4 and substantially all the carbon liberated as a result of the vaporization and cracking of the oil therein will adhere to the internal surface of empty chamher 4. Upon reaching incandescence this carbon will react with the steam to form blue gas. Carbon remaining on the walls ofchamber 4 will be converted to heat on a subsequent blast run. The mixture of gases discharges from the top of chamber 4, through crossover 34 into empty chamber 38, also at a high temperature due to the previous blasting operation; wherein decomposition of the oil vapor molecules continues with further deposition of carbon on the walls of empty chamber 38 (minor in amountin com parison with the carbon deposited in chamber 4) and further production of bluefgas during the downward passage of the gas and steam'in vessel 35. By the time the gases pass through orifice 42 cracking of the oil into gas has in large measure been accomplished and generally more than 90% of the total carbon resulting from the conversion of the oil has been deposited on the walls of empty chambers 4 and 38 out of the pathof checkerbrick 4|. The gases are fixed by their downward passage through checkerbrick 4| which is at a temperature highfenough to finish the-decomposition of the oil vapors and to convert such oilvapors into an oil gas.

Recycling of the make gas'desirably in' an 10 amount between 10 and 35% of the volumeof make gas into inlet 2| may be accomplished in various manners, as for example by the use of a steam injector to withdraw a portion of the make gas from' the bottomof vessel 35 was an alternative to install a gas exhauster to withdraw make gas from the foul main and introducethe make gas with steam at the top of riserpipe [8. In some instances the'return of a portion of make gas from crossover 34 to riser pipe 9; or' the bottom of fixing chamber-1 may be fou'nd advantageous. It is not essential to admix the hydrocarbon carrier gas with the steam prior to passage through refractories 6 and therefore the carrier gas maybe commingled with the steam near the bottom. entrance of reaction chamber 4. A normally gaseous hydrocarbon such as methane; ethane, propane or. mixtures thereof may be employed as the hydrocarbon carrier gas from an external source.

The combination of hydrocarbon carrier gas and my method of blasting and making have the cumulative efiect of reducing the'amount of carbon deposited which permits the use of smaller quantities of steam which in turn results 'in a higher calorific gassince the greater theamount of steam the lower the B.'t. u. content of the gas. The make gases leaving'the bottom of vessel 35 pass through conduit -44 up through riser pipe 43 and thence discharge through conduit 5| and valve Hi to conventional washbox and foul gas main, not shown in the drawing.

The reverse blast period and make period are s milar to the make period and blast period previously described and need no further elaboration other than the statement that the flow of fluids 1s downwardly through riser pipe 43, upwardly through vessel 35, downwardly through vessel 1 and upwardly and out through riser pipe 9. I

The time for individual blast and make periods will vary dependent upon the nature of the charging oil, operating conditions, and quality of gas desired. Blast and make DBIiOdSjOf from 3-19 minutes duration will ordinarily "be found satisfactory. High superatmospheric Orsubatmospheric pressures are unnecessary since the operation of my process may becarriecl out efficiently at substantially atmospheric pressure.

In order to avoid an explosion hazard, the systemshould be purged of combustible gas prior to the introduction of air in the succeeding blast period. Purging may be accomplished by passing steam 1n through line 41 and out through the top ofriserpipell. a it In the practice of my process .a wide variety of charging stocks ranging from LP. gas to heavy liquid hydrocarbon oils may betreated. A particular advantage of the present invention resides in the provision of an apparatus and process for the conversiontif low grade. hydrocarbon oils such as heavy cracked residuums having a Conradson carbon number in excess of 10 into high gravity low B. t. In. gas without'choking up the apparatus with carbon and, indeed, with the total elimination of carbonaceous material as by-produc Although certain preferred vembodiments of the invention have been disclosed for purpose of illustration it will be evident that various changes and modifications may be made therein without departing from the scope and spirit of the inven- I claim: v

1. A process for the gases'which comprises,

production r ecm u time (a) a blast period wheret ere u t e h i t bi iiatmm empty zone thereby transferring hea -fr m the combustion gases ,to its walls and burning any carbonaceous deposits thereon by means 91 the excess aim-continuing the passage ofcq bustign gases ldownwardly through the intersti s of refractories contained'in' a-fourth zone thereby, heatingfthe retractories therein, and. then discharging the combustion gases'to the atmosphere through a second riser-pipe leading from the base of the fourth zone; (1)) a purge period for the' evacuation ofcombustion gases contained in the system whereinsteam introduced into the'first riserpipe-passes upwardly through the first and second zones; downwardly through the third and fourth zones', and discharges to the atmosphere through the second riser pipe (c) a make'per-iodwherein steam introduced intoithe first riser pipe is admixed with a hydrocarbon carriergas and the mixturepasses upwardly through the refractories in the first zone, thence upwardly into the second empty zone countercurrent to downwardly injected hydrocarbon charging stocky-maintaining the velocity. of. the mixture 'of's'team' and hydrocarbon carrier. gas suificiently high" to prevent passage of carbonaceousmaterial downwardly out of the second zone, "withdrawing gaseous constituents substantially free of solid and liquid carbonaceous material from the top of the second empty zone, passing the gaseous constituents downwardly through the thirdfand fourth zones thereby fixing the gas-{and discharging the gaseous constituents from the bottom of the fourth zone through the second riser pipe; (11) a second purge period for the displacement of gaseous constituents in the system wherein ,stearn introduced into the first riser pipe passes upwardly through the first and second zones, downwardly through the third and fourth zones; and discl iarges'through the second riser pipej e) a reverse'blast period as described-in (it) above; "(f)' a reversepurge' period as described in (b) above; (g) a'reverse make period as described in (a) above and (h) a reverse purge periodas described in"i(d.)j above.

2. A process for theproduction'of combustible gases which comprises; (a) a blast period wherein air passes downwardly througha previously heated riser pipe thereby effecting partial heat; ing of the air, upwardlythrough the'interstices of heated refractories contained in a first zone thereby further heating the air, passing the preheated air into asecond empty zone wherein secondary air and heat oil are introduced, which latter burns to impart heat to the'walls' of the empty zone, passing the combustion gases resulting from the reaction of the heat oil and air together with excess air downwardly through a third empty zone thereby transferring heat from the combustion gases to its walls and burning any carbonaceous deposits thereon by means. of the excess air, continuing the passage of combustion gases downwardly through the interstices of refractories contained in a fourth Zone thereby he s s m hsrhihi eih t riser R p a ses wer d ewed .zhhe fahd. c, third a d fou h ha s thud o h e t r hehth e nd rite; 9 make er d re n te r u eqr h q the t er p is e h et'hrdtqha hhh r gas and t ch eses 1 h. ardly through e. efracwries h th h.

h h cft e sshnd. m ty zphe pes lhs the gaseous ch st tue t hwnwa d r r ugh th third and fourth zones thereby fixing" the gas, recycling 5 hh t h o theea ehhs c hstiti hh to the fi zphe a t e. n res h ter ier as a d har ng gaseous. .cqhstt uefits rhm. ths ot o t e t un h zhhethrhh h the Stand r r h re; se nd-Purse nette flu. th p a em nt f hastens echstitueh sih the ys: m h r in team nt oduced. i to the. fi st. pip Pa 'upweh lvthrqush th st and 0 zhh dhwhw idly thrcueh th h rd and u h oh s a d scharges th hi eh en? s r pipe? a r v rse blast icdes csqri td in a b ve f a reverse urse DQ13051- dc..- r d n. there (92h er is period as de cr bed in ab and h). a: rer rse p ee p r oda descr be. .d.- a g e 3- Ap a tu ap ed. for .cgn rt ie. hrsm.- h h i tq cqg hust lesas wh c comp m heticn of; a first chamber; atheist Part al y dwi refract r hex mercies th rein to pe mi th passa e c ga 'thi ethmuehr a e n mpt re a tory. 1. chamb r; a r st i ed passa w y onnectin the ten .91 the st chambe with't e. .t m Qf the second hamb r a th r empt tci eht rr l a h r a as hannel. cohh ecch aud h ..l. em ty. a am rht leas pa tia ly ii l dw th a ,c hey. mass has mercies th re n ch h tthe ass e attest ratittered? h w t the: h s. heh d a it teeth). the bottom ofQthe first eh t ined. ve se s. chhhe ted at t .thhs hrs a 'h ahhe hath. Yl h h e ztei= h9y qe an em t the-ta s? hq ee hti ss tti a two vertical riser pi zpes t 1 he ht bhte'the esse s WEI; eac n rice rh s s th t r the b tory lined duplicate vessels connected at their tops by a gas channel, each vessel constructed to provide an empty chamber'above another chamher at least partially filled with refractory material with voids therebetween to permit passage of gas therethrough and'divided therefrom by a refractory orifice, two vertical refractory lined riser pipes extending upwardly to a height above the vessels with each riser pipe connected to the base of each vessel, a stack valve fitted to the top of each riser pipe, conduits leading from the top of each riser pipe connected to a threeway valve for reversal of fiow in the apparatus and for release of make gas, inlets for the introduction of primary air and steam into each riser pipe, conduits for the return of recycle make gas t'otthe bottom of each vessel, inlets for the introduction .of secondary air and heat oil into each empty'chamber, and downwardly directed spray nozzles disposed near the top of each empty chamber for the injectionof hydrocarbon oil.

6. A process for the production of combustible gas which comprises passing air upwardly through the interstices of heated refractories contained in a first zone thereby preheating the air, passing the preheated air into a'second empty zone wherein heating fluid is introduced, which latter burns to impart heat to the walls of the empty zone," passing the resultant combustion gases downwardly through a third empty zone thereby transferring heat from the combustion gases to its walls, continuing the passage of combustion gases downwardly through the interstices of refractories contained in a fourth zone thereby heating the refractories therein, and then discharging the combustion gases from the fourth zone; passing steam upwardly through the refractories of the first zone thereby heating and expanding the steam, passing the expanded steam upwardly into the second empty zonecountercurrent to downwardly injected hydrocarbon charging stock, maintaining the velocity of the steam, sufficiently high to substantially prevent passage .of carbonaceous material downwardly out of the second zone, withdrawing gaseous constituents substantially free of solid and liquid carbonaceous material from the top of the second empty zone, passing the gaseous constituents downwardly through the third and fourth zones thereby fixing the gas, and discharging the gaseous constituents from the fourth zone; passing air upwardly through the interstices of heated refractories contained in the fourth zone thereby preheating the air, passing the preheated air into the third empty zone wherein heating fluid is introduced, which latter burns to impart heat to the walls of the third empty zone, passing the resultant combustion gases downwardly through the second empty zone thereby transferring heat from the combustion gases to its walls, continuing the passage of combustion gases downwardly through the interstices of refractories contained in the first zone thereby heating the refractories therein, and then discharging the combustion gases from the first zone; passing steam upwardly through the refractories of the fourth zone thereby heating and expanding the steam, passing the expanded steam upwardly into the third empty zone countercurrent to downwardly injected hydrocarbon charging stock, maintaining the velocity of the steam suificiently high to substantially prevent passage of carbonaceous material downwardly out of the third empty zone, withdrawing gaseous constituents substantially free of solid and liquid carbonaceous material from the top of the third empty zone, passing the gaseous'constituents downwardly through the second and first zones thereby fixing the gas, and discharging the gaseous constituents from the first zone.

7;A process for the production of combustible gas which comprises passing air upwardly through the interstices of heated refractories contained in a first zone thereby preheating the air, passing the preheated air into a second empty zone wherein heating fluid is introduced,

which latter burns to impart heat to the walls of the empty zone, passing the resultant combustion gases downwardly through a third empty zone thereby transferring heat from the cornbustion gases to its walls, continuing the passage of combustion gases downwardly through the'interstices of refractories contained in a fourth zone thereby heating the refractories therein, and then discharging the combustion gases from the fourth zone; passing steam upwardly through refractories of the first zone thereby heating and expanding the steam, introducing ahydrocarbon carrier gas into the second zone, passing the mixture of expanded steam and hydrocarbon carrier gas upwardly through the second empty zone countercurrent to downwardly injected hydrocarbon charging stock, maintaining the velocity of the steam and gas mixture sufiiciently high to prevent passage of carbonaceous material downwardly'within the second zone, withdrawing gaseous constituents substantially free of solid and liquid carbonaceous material from the top of the second empty zone, passing the gaseous constituents downwardly through the third and fourth zones thereby fixing the gas, and discharging the gaseous constituents from the fourth zone; passing air upwardly through the interstices of heated refractories contained in the fourth zone thereby preheating the air, passing the preheated air into the third empty zone wherein heating fluid isintroduced, which latter burns to impart heat tothe walls of the third empty zone, passing the resultant combustion gases downwardly through the second empty zone thereby transferring heat from the combustion gases to its walls, continuing the passage of com bustion gases downwardly through the interstices of refractories contained in the first zone thereby heating the refractories therein, and then discharging the combustion gases from the first zone; passing steam upwardly through the refractories of the fourth zone thereby heating and expanding the steam, introducing a hydrocarbon carrier gas into the third zone,'passing the mixture of expanded steam and hydrocarbon carrier gas upwardly through the third empty zone countercurrent to downwardly injected hydrocarbon charging stock, maintaining the velocity of the steam and gas mixture sumciently high to prevent passage of carbonaceous material downwardly out of the third zone, with- 15. r wi e tal eenstit ents sub antia ly. ree? f: i d ghts? er eneee us mate i l; from h pj f he hirs r mpty. ane passing the s s u n tituen s. ow wardly. um-ushh c a r t tense ti erele ;v e as.

n d et ne. the. ase us. consti ue s. r the first; zone.

81 r t o he i q uc en. i' m l sti e gas Y which. comprises passing air upwardly r u h e er t ees. Qt ate ei e ries ntain i firs zen her byn eheatin th i pa sin he r he ted a r i to ajl econd. p y zone wherein heating fluid is introduced, which latter burns to impart heat to the walls of. the

empty, zone, passing the resultantcombustion gases downwardly through a third'ernptyL zone therehy transferring heatfrom the combustion gases to its walls, continuingthe passage ,of come bustion gases downwardly through theinte stices of refractories contained a fourth zone there-y, by heat he; i e riestliereia. and hen i c ar n h mbustion. ases. fr the ourt o e; s in steam. up ard y hrough the .refractories of the first ,zone therehy heating. and se d ne h teem.., n r .uc.ina nto. th n n a p r iene eeifiuent ea e-o trea tion produgts formed in. the sec ond zone, pass} in themixture ofjexpanded steam and said ef: fluent gaseous reaetipn, productsupwardly th oughfthe second empty zone .countercurrent o downw r l ini t dhyd oe r n gi stoc k maintaining the velocity, of the steamend gas mihturesuficiently, high to prevent passage.

of carbonaceous materiai downwardiyoutof the second zone, withdrawing gaseous constituents. substantially free; otsolid and liquid carbonaw. eeous material from the top ofthesecond. empty.

zone, passing the gaseous I constituents down e l h h the thi emi eu th e tse 'er by fixing e. s; ana iee arsz n g h sa o constituents from the; fourth zone; passing air,

w r thr h. heti t rstie sle he te fi e.- fractories containedin the fourth zone thereby preheating the ai r passing preheated air intc, e third m ty z ne whe ein hea n fluid is introduced,- which latter to impart heat to the walls of jthe third empty zone, passing. the resultant combustion gases downwardly through the et iempti z ne, her r nsien ne heat from the combustion gasesto itswall s, continuing the passage of compustiqn gases downwardly through the interstices oi' refractories contained in the'firstzone thereby heating there fractories therein,and then discharging the coin: bustion gases from the first zone; passing steam upwardly through the refractories in the fourth;

zone therebyhea'tingand expanding the steam,

introducing into the third zone a portion ofgthe carbon chargingv stock,

emue t a eous. reaction .pmrl e sform i th third zone, passing the mixture of expanded te m and. sa d. e ent. aseou eeet p p ucts pw rdly. t rou h. h hir empty n countercurrentto, downwardly injected hydrocar bQIi; .C1 %LIging stock, maintaining .the. velocity, of 1 thesteamand gas mixture. sufficitzntlyhigh to prevent passage of carbonaceous materialdownwardiy outof the third zone, withdrawing. gaseous constituents substantially free of. solid and liquid carbonaceous materialfrom, the top of the third empty Zone, passing the, gaseous.;constitu.-. ents downwardly, throughjthe second and first.

zones thereby. fixing. the gas, and discharging. the gaseous constituents from the first zone.

9.;Apparatus adapted I for converting hydrocarbons "into comhustible gas which comprises a coinhinationofa first chamber at..least,par-.

tially, fllledwith refractory masshaving voids therein to permit. thejpassageof -gas therethrough, asecondempty refractory lined chain b811,, arestricted, I passageway. connecting. the top of the, first chamber with the bottom of. thesec-u 0nd chamber, a, third empty refractory lined chamber, a gas channel. connecting. the tops of the second and third empty, chambers, a. fourth chamber at least partially, filled with a, retractory: mass having voidsthere'in to permitthe passage of ,gas ,therethrough, a restricted. passageway. connecting the. bottomof. the third chamber. with thetop oLthe, fourth chamber, two riser pipes extending upwardly to a height above. the chambers with oneriser pipe connected at its .base to thebottom of the first chamber and the other riser. pipe. connected at its base tothebottom ofthejourthchamber, inlets for the introduction. oi, airinto the first and fourth chambers, inletsfor the introduction-of a. combustible. fluid into the second and. third chamber a.nd. Spray nozzles near theitop ofthe second and third chambers orthe injection of hydro- HARR B. PEARSON;

BEEERENCES CITED 7 The. followingreferences are of record in the iile of this patent:

UNITED. STATES PATENTS Number; Name Date 1,321,333 'Tolman sept l, 1931 2,131,696] Brandegee' Sept, 27', 1938 47,44 Ro s Sept- 26; 19 2,206,189 l-iillhouse July 2 1940 2,203,123" Duncan July 16, 19.40 2,267,43t Tenney Dec ..23; 19.41 2,494,575

Claims

1. A PROCESS FOR THE PRODUCTION OF COMBUSTIBLE GASES WHICH COMPRISES, (A) A BLAST PERIOD WHEREIN AIR PASSES DOWNWARDLY THROUGH A PREVIOUSLY HEATED RISER PIPE THEREBY EFFECTING PARTIAL HEATING OF THE AIR, UPWARDLY THROUGH THE INTERSTICES OF HEATED REFRACTORIES CONTAINED IN A FIRST ZONE THEREBY FURTHER HEATING THE AIR, PASSING THE PREHEATED AIR INTO A SECOND EMPTY ZONE WHEREIN SECONDARY AIR AND HEATING FLUID ARE INTRODUCED, WHICH LATTER BURNS TO IMPART HEAT TO THE WALLS OF THE EMPTY ZONE, PASSING THE COMBUSTION GASES RESULTING FROM THE REACTION OF THE COMBUSTIBLE FLUID AND AIR TOGETHER WITH EXCESS AIR DOWNWARDLY THROUGH A THIRD EMPTY ZONE THEREBY TRANSFERRING HEAT FROM THE COMBUSTION GASES TO ITS WALLS AND BURNING ANY CARBONACEOUS DEPOSITS THEREON BY MEANS OF THE EXCESS AIR, COMTINUING THE PASSAGE OF COMBUSTION GASES DOWNWARDLY THROUGH THE INTERSTICES OF REFRACTORIES CONTAINED IN A FOURTH ZONE THEREBY HEATING THE REFRACTORIES THEREIN, AND THEN DISCHARGING THE COMBUSTION GASES TO THE ATMOSPHERE THROUGH A SECOND RISER PIPE LEADING FROM THE BASE OF THE FOURTH ZONE; (B) A PURGE PERIOD FOR THE EVACUATION OF COMBUSTION GASES CONTAINED IN THE SYSTEM WHEREIN STEAM INTRODUCED INTO THE FIRST RISER PIPE PASSES UPWARDLY THROUGH THE FIRST AND SECOND ZONES, DOWNWARDLY THROUGH THE THIRD AND FOURTH ZONES, AND DISCHARGES TO THE ATMOSPHERE THROUGH THE SECOND RISER PIPE; (C) A MAKE PERIOD WHEREIN STEAM INTRODUCED INTO THE FIRST RISER PIPE IS ADMIXED WITH A HYDROCARBON CARRIER GAS AND THE MIXTURE PASSES UPWARDLY THROUGH THE REFRACTORIES IN THE FIRST ZONE, THENCE UPWARDLY INTO THE SECOND EMPTY ZONE COUNTERCURRENT TO DOWNWARDLY INJECTED HYDROCARBON CHARGING STOCK, MAINTIANING THE VELOCITY OF THE MIXTURE OF STEAM AND HYDROCARBON CARRIER GAS SUFFICIENTLY HIGH TO PREVENT PASSAGE OF CARBONACEOUS MATERIAL DOWNWARDLY OUT OF THE SECOND ZONE, WITHDRAWING GASEOS CONSTITUENTS SUBSTANTIALLY FREE OF SOLID AND LIQUID CARBONACEOUS MATERIAL FROM THE TOP OF THE SECOND EMPTY ZONE, PASSING THE GASEOUS CONSTITUENTS DOWNWARDLY THROUGH THE THIRD AND FOURTH ZONES THEREBY FIXING THE GAS, AND DISCHARGING THE GASEOUS CONSTITUENTS FROM THE BOTTOM OF THE FOURTH ZONE THROUGH THE SECOND RISER PIPE; (D) A SECOND PURGE PERIOD FOR THE DISPLACEMENT OF GASEOUS CONSTITUENTS IN THE SYSTEM WHEREIN STEAM INTRODUCED INTO THE FIRST RISER PIPE PASSES UPWARDLY THROUGH THE FIRST AND SECOND ZONES, DOWNWARDLY THROUGH THE THIRD AND FOURTH ZONES, AND DISCHARGES THROUGH THE SECOND RISER PIPE; (E) A REVERSE BLAST PERIOD AS DESCRIBED IN (A) ABOVE; (F) A REVERSE PURGE PERIOD AS DESCRIBED IN (B) ABOVE; (G) A REVERSE MAKE PERIOD AS DESCRIBED IN (C) ABOVE AND (H) A REVERSE PURGE PERIOD AS DESCRIBED IN (D) ABOVE.