claim is,:- 1. In the low temperatiire c,,trbonization 15 and distillation of sbale and the lilce, the process of prodiicing a controlled rapid low temperat-ure carbonization wliieli comprises initiating, maintaining and controlling a downwardly advancing zone of low 20 temperature carbonization and distillation in a moist column of material by a downdraft of hot gases theretlirough, said gases comj)rising returne(I combustible gases, arising from the operation, burning with 25 admixed air and control of the advance of the zone being e:ffected by regulation of the amount and proportion of the s,tid gases and air. 2. In the low temper,,tttire carbonization 30 and distillation of slia-le and the like, the process which comprises initiating, inaintaining and controlling a downwardly advancing zone of low temperature carboni7ation and distillation in ,t inoist column of 35 material by a dowiidraft of bot gases therethrough, said -ases comprising returned combiistible gas@s arising from the operation, burning with admixed air in amount insufficient for their combustion and con40 trol of the advance of the zone being effect7 ed by regulation of the amoiint and proportion of the said gases and air. 3. In the low temperature carbonization and distillation of shale and the like, the 45 process of producing and rnaintaining a regulated rapid low temperature carbonization and distillation which comprises transmitting downwardly throu,-Ii a pervious moist column of sliale a burnin- draft of 50 combustible aases and air, regulation of the carbonization being effected by control of the amotiiit and proportions ot su@li gases and -,tir so burning. 4. Ili the low temperattire carbonization 55 and distillation of sliale and the lilie@ the process -wliieh coniprisestransmitting downw,,irdly throtiab a pervioiis moist coltimn of slial6 a burniiig dr,,ift of combustible gases .tnd air to (rii,e a-n advancing zone of car60 bonization and distillation; the bottom of the column beiiig niaintaiiied at a temperttiire not above 2120 F. iiiitil just before the downwardly advinciii- zoiie of carbonization approaclies'it t,nd an intermediate zone 65 of preheating and di-ving bet-ween the advancing face.'of the carbonizing zone and the portion of the column at a temperature not above 212' P. I)eing niaintained I)y suitable adjusti-tient of the air iind gtises so introduced. 70 5. The process of cai-I)onizing oil shale or the like in a closed vertical cliamber %vhich comprises initiating or setting up a zone of gaseous combustion al)ove a body of sliale in said cliamber to initiate and iiia-intain t 76 zone of carbonization in siid clianiber ,in(I causing said zone of carl)oiiizttion to I)rogress downwardly throu-ii the coliimii or body of shale in said chaiiiber. 6. The process of carl)oniziiig oil sliilc@ 80 or the like in a, closed vei-tieal cliaiiiic-iwhich comprises initiiting or s(!tting iij) a zone of gaseous coml)ustio-n giving a I)ody of flamin(y gases of reducing natlil-e, above a body of shale in said clianil)er to initi-,tte 85 and irtaintain a zone of carbonizatioil ill said chamber and catisin- said zone of (!al-- bonization to progress downwar(llv tlirouryli r', the column or body of shale in stid cliaiiiber. 00 7. The pi-ocess whicli coniprises initiating a zone of gaseous combustion at the top of a body of shale ;in a closed cliaml)er, aii(I setting up a dowildraft of the I)i,oducts of said combustion tbrough the body of sbale, 95 whereby a zone of earbonizatioll is catised to progress through said body. 1, ating a zolhe O?ro,,,@ss which coinprises cre gaseous combustion by burning a niixture of air and gas in tlle top of a loo closed chamber containin- a body of sliale, causiiig the resulting flaming gaseous products to pass downwardly tlirotigh sa-idbody, drawing oiT and treating in the usual way the condensed and uncondensed products of 105 distillation from the bottoni of said cliaiftber, and returning some of the uncondensed gases in the form of combustible atis to the top of said chamber to maintain -said zone of gaseous combustion. 110 9. The process of ext-racting oil froin shale and the like which consists in creating @n, zone of gaseous combustion above a body of shale in a closed chamber, causing a downward draft of the products of said 115 zone of combustion through the body of shale recovering the distillation products from 7 the bottom of said cliamber, ind retuming some of the Laseous Droducts to said zone of combustion thereir@. 120 10. In the low temperature distillation and carbonization of shale, tlxe process which comprises introducing a burningmixture of combustible gas and air above a vertical perviotis column of shale having ',I 12,@ moist base aiid 1)assing said iiiixtiire do',Vnwardly thereth@oiigh and t-liereby initiat.in(r and propagating a downwardly nioving zone of carbonization aiid distillatioii with a substantial zone of preheating aild 130

11536,696 drying between said carbonization zone and said moist base until just before the advancing face of the carbonization zone Feaches the bottom of the column, the heating action of the burning mixture and its volume being balanced against the cooiince action of the raoisture and liqiiids in the' line 0-f propagation to control the progress of the carbonization zone and to preserve a substantial zone of preheating and drying. le In testimony whereof, I have hereunto affixed my signature. GEORGE WIGI-ITMAN WALLACE.

Patented May 5, im. lpS36,v696 UNITED STATES PATENT OFFICE* GEORGE WIGHTXAN WA-LLACA OF SAN@ FRANCISCO, CALITORN14k. PROCESS OF CAR330NIZING. Application Itled September 17, 1923. gerial- No. 663,240. To allwhom it i)?ay concern: Be it known tliut 1, GFORGF W. I'VALLACF, a citizen of the United States, residing at S,in Francisco, in the coiinty of San Frons cisco and Stato of Cilifoi-nia, lian,e invented certain new ,ind iiseftil Improvements in Pro@esses of Carl)onizing, of %vliieh the folIoNi,ing is a specification. This iiivention relates to processes of c,,irio bonizing; and it coiiipri,-es a method of carboniziiig slitile, licr ,nite, coal, etc., to obtaiii valuable volatilizable products whei-ein shale, or -'tlie like (tistially, but@ not necess,,trily, iiioist or moistened) is -carbonized in a vei.-- 15 tical eolumn under conditions causin(r a traiisverse band or zone of carbonizatioii to advaiiee progressively downward towards and to the colder, moist lower end, the temperature in this zone being ustially arotitid 20 8000 F aind the the downward -progression of the, zone being effected by a@ liot dowii draft of returned combtistible gases adniixed Avith air; all as more fully hereillafter set fortli and as claiined. 25 In distilling shale, lignite, coal, etc., to obtain oils ,tiid tars and ainmonia, t.lie bituminoiis bodies present break tip primarily by an actioln @n,,tlogotis to the cliarriiig of wood; an action whicli, as a whole, if not ae30 tti-,illv exotliermic, at all events requires the ad(iiiion of veit little forei-ii heat once t'lie materials are brotiglit to a reacting teinperature. The action is the same as that forming the first stage in cokin a coal and is call(@d .35 carbonization; -,i- terii-i wriieh may be hercused. Once initiated at any point in a mass of bot ftiel, the decomposition reaction tends to' become self-propagatino, and advance elsewhere. Possibly the'ac@tual decbmposi40 tioii itself is alivays exotliermic; btit the P-et resiilt of the coni@lex of actions taking plice and viporization of the volatile product.for.nied, with constimption of heit, may or may not be a liberition of heat. However, 45 if added heat is reqiiired, the aiiiouiit, ip. thermal iinits, is, as iioted, iisutilly very little. Witli v-,irious coals under v,,trious conditioiis, recorded restilts vary between a liberation of ,iboiit 780 Brit,sh tliermal tinits 50 pei, pouiid of coal to aii absorl)tion of about 170. Oiie of the products of the primarv decompositioii is ilways combustible glis - Iiyleiie, etliaiie, etc.) iii(I if lieatiiig coiiditions be not careftilly regulited, tl)e 55 am,3unt of this gis is iiiaterially augmente(I by secoi-idary deeomposition of the oils aiid tars primarily produced. This is of cotirse undesi rable, except where gas is the product sought . It is well i-ecognized in the art thit low 60 tempe rature disfillation is desirable in order to obtain a maximum of oils and tars; an([ many methods of distill@ng have been proposed with this end in view. For t-he most part, liowever, they have been unsuccessiul 06 in securing'the full result @ouglit because of the engineering and technical difficulties incide rt to lieatin(y any substantial inass of pulver ulent or fi@tgmentary nature evenly and io exact temperatures tllroughout; and 70 partic ularly mhere, as in the present case, the result is, or may be, a self-propagating exoth errnic reaction. Ordinarily, moreover, t-he methods are, thermally speaking, expensive; tliey require much heat to be used and 75 partic ularly with externalty heated retorts; this beino' especially true where substantial yields' orammonia are-sought and currents of steam are used tq assi2.t in its extrication. Tlle qtiestion of the heat necessary is par- 80 ticular ly serious in dealing with sliales ar.,d lignite s high in mineral matter, of low fuel value. It is the object of the present invention to provid e a rnet-hod particularly applicable to 85 the treatment of oil shales, but also useful with lignites and coals, in order to produce maxi mum yields of oils and tars, as well 'i@, of ammonia, with a minimum consumption of fuel. Ile solid product of the action mav 90 be mineral matter or ash, or it may be a ca@- bonize d mass of coky or semi-coky nature, having fuel valiie. In 6rder to awomplisli my end, I take advanta'oe of the stated selfpropa g,,tting nature of@the carbonizin(r re- 95 action, instittiting a carbonizing reaction ill tlle top of a colunin or body of sliale in a suitabl e container and effecting a downwai-d re,- ulated travel of this zone of carbonizintowar ds and to the lower end of the column. 100 The carbonizing action is, as stated ' usually exot@ hermic, that is, is attended with a loc,,il evoluti on of heat and ah increase in teniperatu re. Iii order to control the re-,ictioii ind its propagation, I balance the heat ard 105 volum e of a downdraf t of. bul,niiic_r gases traveli n- in the directiqn of propagation agains t the cooling effect of moisture in tl)e line of tdvance. In so doing, I am enabled to achieve @t new resiilt: rapid ea]-bonization 110 at a controlled aild low temper',Vture. In practi ce, above (or in heat communicatiiig.

re@l-ationsllip to) the heacl of the column of sliale I burli ffases to produce a higher ternperattire tliin that required to iniii,,ite carboniz,,ition, while the body of shale is ivet or moist to a point just below the temportiry locus of tlle zone of carbonization, and thei-efore at a temperature not exceedin- 212' 1-@. Ile exact dist,,tiiee between the moist zone where sudden cooling takes place an(I tl)e 10 advanciii- Iligh temperati-ire face of the carboiiizati(@i-i zone depends on the voltime of hot gases passing,.and dry out the iiiaterial. The ch,,irge is usual@f in fra(-llleiits of tia,o incli size or less, though "run of 15 mine" may be used and it holds -,vhatever water will adhere, the rest draining clownward. Hot -ases are passed downward t-lirotigh the sliale towards the cold end. By regulatintr the quantity of -aseq in the zl@ 20 downdraft'and their teinpei,,tture, obviotis@17 1 can exercise exact control of the progress of th6 carbonization zone. It is a iiiatter of balancing the lieat and the voltiiyi(@ of the (rases in the droivndraff ,igaiiist the cooling 25 ;ffect of the moistiire in the shale I)elow the zone. 'LTsiiall-v some of the (@ombiistible g.,tses restiltiii(y i@om the action itselif and collected beyond the condensers (whicli I in,,t37 liere 30 call "tail gases") are retui-ned to a point in the treating apparatiis just tbove the miss of shale under treatment and ai-e there burnt witl-l air. The amotint of heat de35 veloped depends upon the quantity of gas so introduced and burnt. The hot mixed body of gases passing dg-vvnward througli the ma-,-s of shale gives the he,,tt iiecessary to initiate and maintain the carbonization; i. e., the lieat required to coii-ip(!lisate, for 40 radiation, for lie,.iting the solid m-,iterials to a, somewhat higlier temperature, foi- i,aporization and the like. The downdraft carries heat, as well as vapors and gases, 45 forward bevond the lower advancing fa(,e of the zone of carboliization aiid pi,elic@al-s the materials to be c,,irbonized. The primary products of carbonization are coole(I tlit@re.by. Under t,he cii-cumstaiiees, these product,-, 50 leave the advancing face really as a sort of fog or fume, well distributed throtigli the draft current and there is no tendency for tlle sliale to clog with tar. The z(,ne of prelieating below the idvancin- face ) f the car5 5 bonizing zone is 'limited i-ii its lengtli by the presence of liqtiid water therebelow. At some point no(t far below the ,idv@iiicing fice of the carbonizing zone, wliieh I iis ' iiilIN keep at a temperature around 8001 F ', tl@e 60 temperature of the shale cannot exceed 2120 F. because of evaporatinr water and liqiiids. Betiveen these poiiits is a prelieating -,ind dryliig zone ()f a lengtli del@endir,.' ,)- - til)on the fras speed. The moisttire in the fiiel is evlaiorated in the prelieating zoiie with a eorresponding consumption of he-,it units; but these lieat iinits al-e largely -iven. baelz to the shale wlion the water vapor !)asses downward and is a-aiii condense([ b'y tlie, underlyin- 1,,tyers of cool -,Iiale. The pre.9- eiiec.of tlle water vtpor jtist I)elow the ad- 70 vancing face of the carboniziii(Y zone tti(i@s materially in giving Iiic,@h yields of a]Tllvlonia, and is also advant,,igeoi.is in pro(Iticin- t quick cooliiig of the vadoi,s leaviilg t'lie bonizing face, witli the downdi-aft. Oil sll,,,](@ 75 cont-,iining 15 to 20 per ceiit of oil or I)ituininous matter may cai-ry -,is Iii,("h as 8 to 12 per cent of water ajid retains a considei-- able amount of 1-1,0 even wlicn pi.,,s(!d tlii-ougli a drier or pi,eheater or Ileat ex- 50 chan(,rei@. In t,lie operation of the process a, ju,-,t described, the water naturally preseiit in the sliale, tilougli ilot absolutely essential, is defiiiitely advantageous, instead of being detrimeiital. In addition to the water or 85 moisture in the shale, some H,O is forme(I by the coinbiistion of the rettiriied ttil gases aiid these gases ai.-e iistially moist in any event; they leaa,e the scrtibl)er s,,tturated witli water vapor. It is, lioNvevei.-, often usefiii 90 to add some water witli niaterial iiot nattirally carryin . g rnucli water. The water in tl,.e material, or that ,tdded, while vaporizing during the process, is largely again liquifiecl; and to this extent the vaporization does 9 not involve any loss of lieat units. Usirl(, ,i sliale witli, say, 10 per cent of water in iti ii-iucli of this water is extracted from tl)e sliale in the preqent process in the liquid 1(0 form. At the base of the column pass away liquid water and liquid oily and tarry products, tocrether with various gases and vapors resultin(r from the operation. Ordinarily, t, 101-) until the carbonizing and prehe,.tting zories approacli the bottom of the column of shale, the ten-iperature at this point is around 140-1600 F. The gases drawn off at this point are a iiiixture of the bydrocarbon gases 110 produced in carbonization with producer gas forined by the action of the air on the carbon, and are saturated with water vapor at tlle temperature obtaining at the base of tlle column. They carry mucli oil and water as 115 a fog or fume. Ordinarily, I draw off liquid water and oils into a settling tanlc for separation and pass the -ases throligh cooliilg ,tnd scrubbing towers,-wllere there is a further recovery of liquid oils. The final gases 120 may be oil-scrubbed to extract lincondensed vapors. The tail gases, or some portion of them, I may send to storage or return directly to the licad of the columil of sliale to furnish the beating downdraft. Wliere 125 there ,ire several units under the present invention in operation, it is convenielit to have tlieni out of pliase witli eacli other, so tllat those furnisliiii(y miieh gas can stipply.it.to those in which Fli'e development of -as is in- 130 sufficient. Ordin,,irily, I find it bett-er where

plenty of geises are available, to feed more gas than air to the liead of the column thereby giving a downdraft of what maybe called a reducinr nature; i. e., tlier6 is not onougli air addea to burn all the gas. But as stated, at some stage of the operation' sufl,c, there may not be ent gas to do this such event, I use su(- and in li quantity of be necessary to furnish heat and air a olums mald 10 V e o -raft gases. The air reacts with residual carbon -to give producer gas. While I have stated th.,tt the combusition of the gases takes place above the liead of the column of material, yet actually more 15 or less of the combustion mai7 take piace in the interstices of the top layers,by a sort of Ccsurface combustion" effect. The particular way in wliieh combustion is effected above the column depends to some extent upon the 20 inaterial. 'Nnere the materiitl is a sbale hilrh in mineial matter of ftisible nature, I pr@'efer not to have the coinbustion temperature go too high; and wliere the residue, left by carbonization contains enough carbon to 25 make it valuable 6 fuel, as in treating ligiiites and coals, I cut down the access of air as far as possible to that required for furni@hing heat or draft volume. In cither event the presence of a comp-a-ratively large 1 30 proportion of unburnt returned combustible gases is advantageous. ljnder familiar equilibrium principles, the presence of these gases tends to restrain the formation of like gases in carbonization. A-nd they. appear to 35 act to "sliield" the oils. Oxidation in the carbonization zone is not desirable. The oils drawn off at tlle base of the column and those collected in the various scrubbi.ng devices are distilled in the usual way ito 40 obtain commercial oils, gasoline, kero'sene, lubricating oil, etc. @As the carbonization of the sliale is effected in I an atmosphere which coiitains water vapor, a large proportion of the iiitro en 9 45 present in the original matiarial reappears as ammonia-I secure excellen.t yields of am,n-ionia. This ammonia is recovered from the effluent water by the usual pro cesses. In the accompa-nying illustration I have )(I sl-iown, more or less diagrammatically, certain apparatus within the purview of my invention and susceptible of use in performing the described process. This view is in central vertical section, certain I)arts being r)5 shown in elevation. In the showing, Element 1 desi@,rnates a casing or "-encrator" of any suitable material, such a@brickwork, iron, etc., provided with charging iiieans 1, _,,rate 3 and oil receptacle 4. As tlle et 60 shown, , siing is provided at a point ,,tbove the normal level of solid material tlierein witli air inlet 5 aiid gas inlet 6. At the bottom the casing is tapped by outlet pipe 7 leading gases and condensed liquids 65 away. The liquids p,,iss to separator . 8 - shown as provided. with internal baffles whe re the oil and water are separated; each bein g withdrawn for suitable treatment elsewbe re; the oil to be distilled and the woter aoin g to an ammoni,,t separtitor. 'rhe gases 70 in line 7 pass by brancli 9 to water cooled cond enser.- 10, w..ere there is a separation of furth er oil and water, which may go back to 8 throu(rh valved outlet 11, or to similar sepa rating devices. The cooled resid al 75 gase s are witlidrawn by suction fan 12, wliie h produces suction 6n the whole line, and usually sent to a second water cooled cond enser, indicated at 13. Where ammonia is to be recovered, as is generally the case 80 I next pass the gases through one. or more amiii onia scrubbers of the usua,l type. One is shown as 14. Ordinarily, I finally pass tlle gases tlirougli an oil scrubber or absorption tower 15. Tail gase'3 leave this scrubber 85 thro ugli pipe 16, as mucli as mty be wanted bein g returned for the operation through valv ed pipe 17 forn-iing the continuation of iiilet 6 previously alluded to. Branch pipe 18 may be provided leading to gasometer 90 mea ns (.not sliown) for storage purposes or ns. described device r)) may be filled level marked A, 95 an d gas and air supplied to the top of the cas ina to produce a hot downdraft under the i@fluence of suction from fan 12. They ma y of co-Lirse be supplied under pressure, if desired. The hot downdraft of burnin 100 gas es initiates a transve@rse zone of Carbonizat ion which travels steadily downward. In the drawing, I have indicated this traveling transverse'layer some,%@,liat below the top as B. Below is a drying and prelieat- 105 ing zone which I have indicated as C. As the zone of carbonizatioii travels' dowiiwa rd, the hot draft gases passing ahead of it preheat and dry the material in zone C, an d pass on into the untreated or cool shale 110 bel ow; this cooler layer being indicated as a whole by D. Here the gases drop their mo isture, tar and oils, wbich trielfle downwa rd. This action contiriues ulitil the zone of carbonization approacbes the bottom of 115 the column-zone D always remainiiio, at a tempera-ture somewhere below 2120 F. until this time. When tlle zone of carboiiizatio n reaches grate 3, the operation is interru pted and the residual ash or coke (as the 120 cas e niay be) removed. in ,tny suitable manne r. In the case of @oil shale, the residtie is us ually of little heating valtie,, but in treating ii-gnites and the like, it is of considerabl e fuel valtie. The present iiiventioii iS 125 par ticularly applicable to these li(rnites, sin ce it permits of the removal of much of the ir w,,tter in liquid form , i. e., without the co nsumption of heat inei4eiit to di@yiiig, or co mplete drying, in the tisual ways. 150

While I have described the use of combustible gases arising from the operation itself, they may of course be replaced or supplemented by combustible gases froin other sources, such as nattiral gas. As a component of thedowlidraft, natural gas, which is largely methane, has some advantages. The operation as shown and described is discontinuous; successive batelies 10 of shale bein- treated in the renerator; I)tit apparatus may be provided enablii-ig the operation to be made contintious. What I