US1681450A - Edmund geobge weeks - Google Patents

Description

Aug. 21, 192s,

. 1,681,450 v E. G. WEEKS v v LOW TEMPERATURE FUEL DISTILLATIQN4 I Filed Jan. 15, 1924 l l I I v fm1/avro?? Patented Aug. 21, 1928.

lerares 1,681,450 PATENT iii'liltlii...

EDMUNID GEORGE WEEKS, OF DUNSTON, ENGLAND, SESIGNOR Oli NE-HALF TO THE FIRM MERZ 8a MCLELLAN, ENGINEERS,

LOWTEMPERATURE Application led January 1924, Serial No.

rIhis invention consists in improvements in or relating to low'temperaturefuel-distillation and has for its object to eliminate certain difficulties which are met with in treating some kinds of fuel. These fuels possess an oil content sufficiently high for commercial distillation and include those fuels which are liable to stick together during distillation.

In distilling fuel by passing steam, for example iow-pressure superheated steam, through the fuel While it is in a retort, it is found that in the case of certain classes of fuel, e. g. bituminous coals, the particles or lumps of fuel are liable to become sticky and bind together. This has the effect of preventing the charge from travelling evenly through the retort, particularly in the case of a vertical retort, and also obstructs the passage of the steam and gaseous distillates. ln most cases this binding effect can be overcome by raising the temperature of the steam but it has been found in practice that the use of steam superheated above 500O C. is attended with other inconveniences. It has also been found that in the case of some highly bituminous fuels the sticking action is not altogether eliminated even at the highest practicable superheat temperatures.

It is now found according to this invention that a` more efficient distillation is possible with the use of less steam and ata lower temperature if a certain amount of additional heat be generated within the retort itself by the addition to the heated steam of a regulated amount. of air so as to cause the combustion of a limited proportion of the fuel within the retort. The present invention comprises, therefore, a lowtemperature fuel-distillation process in which steam is passed through the fuel in a retort, characterized by supplying a regulated amount of air to the fuel in addition to the steam, and preheating the steam or the air or both so that the mixture of air and steam is raised to a temperature about at or above the ignition temperature of the fuel. p p

In place of steam it may be possible to employk other heating medium, such forexam ple as an inert gas, and the term steam where it occurs in such connection throughout the specification, is to be understood as meaning any suitable heating or heat-conveying medium. Similarly, instead of using atmospheric air, oxygen or an oxygen-con- OF WEE'IMINSTER, Lliilfll'il', ENGLAND.

FUEL DISTILLATIOJS.

686.395, and in Great Britain October 3, 1923.

taining medium may be substituted, and the term air7 also, although used for brevity, is to be imderstood as including other sources of oxygen which may be found desirable for promoting partial combustion of the fuel.

The air is preferably admitted into the lower end of a vertical retort at a position therein above that at which the coke will collect before it is discharged. from the retort and thus the air is prevented from coming into contact with the massed hot colte thereby eliminating as far as possible any chance of igniting the colte. i

It is well known in the operation of gas producers to blow in a mixture of air and steam below the fuel bed. In such apparatus however the object is to obtain as nearly as possible, complete gasification of the fuel leaving only ash to be extracted, and atthe same time to generate the maximum quan-V tity of gas of the highest calorilic value. In the operation of such apparatus the proportion of air to steam varies from about 5:1 to 3:2,5 according to the nature of the producer process, but in such processes combustion of the retort charge has always been commenced by lighting a iire in the producer and blowing it with air to heat up the fuel thoroughly. Y

The present invention dees not contemplate the use of such quantities of air as will bring about combustion of more than a very small portion of the fuel in the retort, say from 2-470. V If more than this becomes consumed the temperature within the retort wili be unduly raised and the quality of the distillates impaired.

It was at first thought that the quantity of air necessary to produce such a small fuel consumption would be insufficient to maintain such combustion, but it has been found that it is niaintained provided that the steam or air or both admitted to the fuel are preheated before admission to the temperature above referred. to.

In general terms the temperature of ignition of coal for example, is between 400- L1:50" C. so that it will be necessary in carrying out the, process topi-cheat the steam or air or both so that the mixture of steam and air is at least at a ten'iperature of 400o C. and preferably to li530o G. to ensure the requisite combustion.

In one convenient form of apparatus forcarrying out the present invention as applied to a vertical retort, there is provided in comhination, means to supply steam and air to the interior ot the retort and preheating` means tor the steam or the air or both.

One construction oiI apparatus embodying the features ot the invention will now he described by: Way of. example onlyfiviththe aid of the accompanying drawings, in Which- 1- Figure 1 shoivssoniewliat diagrainmaticallyar vertical section fthrou gliy the lower; end of aretort, on the line;11 of Figure 2, and

- .Figure 2 is a section on the line 2-2 ot Figurer-y i .y

Y Like reference nuinerals'indicate like parts inhoth figures oithe draWiiigs.--,` f

L Steam iis:v admitted` in the usual manner y through thev transversely:arrangedfsteampipes 010,1 tliefst-ean'i passing` out therefrom through orilicesspacedeatintervals along the sides oit the pipes. al'elowthepipes 10 the retort is Jformed with a hopper-like chamber having discharge outletsil. lThe eolie collects inath'e. chamber prior to its transference to @trucks or vother conveyors, on `which it is removed i i Y uirirfadmission-pipes 12.and 13 are also arrangeditransverselyfot the retort above the Stettin-pipes 11O-iandV :below vcolte extractor de- Vicessueh as coke extractor rollers let. illternatiwely it-hei iairfipipes 12 and. l13 may .he situatedahore the coke extractor rollers iii order to `maintain the combustion zone well above-said rollers andfso protect them `trom tliefeiieet @tithe high;teinperature. The airadmissionf-liiipes,are grouped in pairs side hy side,a}pipe 12 and afpipe 13 being shown in .each pair. VAll the pipes 12 and 13r are supplied;With-air'ftroma single main/15 and controhcoelisflt are provided toregulate the supplyot airfto each of 'thelpipesf y Y Qnefiiipeyoii eachepair is nformedwvith laterally discharging oriliees at intervals along its length and on both sides .o'tit fora portion only o'lwits length. zahswill he seen from Figure 2, thepipes 12 are each 'termed .with orifices entendinggover halft'ythe lengtlrot the piped The .companion pipe; 13 is similarly formed with discharge i orifices. along only v that portionot itslengtlr correspondingto the portionfotthe pipe 12 which is imperforato. Thuslloy means -otthe controlcocks lil) airfmayheadmitted to any desired portion oi the retort and regulation thereby obtained so .as-.to fcontrol the vcombustion.Within `the re- .tortay .Generally allthe pipes 12 and 13 will .besulpplied-With .fair. and the control cocks -Willfaonly'fneed tobeope-rated. to adjustvlior 4any unequality in combustion Which may oc- #fr lt` -is preferable toiprelieat "hoth the.V steam and the air to the temperature required. in

avhieh-jcasethe'main15 Willbeiinderstood as leading from' anair-heater,softhat hot air is supplied to the main. V"Similarly also, the

steainpipes 10 lead 'from a superheater, but

as air heaters and steam superheaters are known in themselves there is no need to illus trate them in the accompanying draivin T he present invention has the following advantages (l) The temperature ot the superheated steam: .neednot, generally speaking, exceed that necessary to raise the tenn'ierature el the mixed steam audlair ahora-i500 C.

.(2)i-ilrny desired distillation temperature may hefobtained hyadniitting moreor less air and thus increasing or.deereasiugthe combustion. ,'lfhis will enable the range to he extendedoit coals ,uhiehmay he used, as coals which require relatively high temperatiires cannot yhe.convenieiitly distilled with pure steam distillation. .i

f 'lhe quantity ot ste-.ini used.\vith pure steaiirdistillationamounted.tosonie i lh. per 1. lh. otlt'uel distilled. illhen using airy in the prolijo,rtion,.for` example, oit a o air to 7 oi" steam, tliequantity et steam per l lh. et lfiiel will he; reduced to het\reeii..l and .t lhs. ylly sidistitutinga certain percentage otair tor steainthe total cost of providing the gaseous heatingmediunilor the retorts is thus considerahly. reduced.

4 'llhe heat generated in the retort h v the partial. combustion o'l.,the luel undeigoingl distillatioiris utilized. at about A1.0() per cent eliiciency since itis generated iii the retort itselt. 1 i

(5)'l`he Volume oitv the gases p2 ing through the retort is .increased when aul is used, .ivherehy the oil vapours are more rapidly carried away with less riskoil condensa l ion and re-distillatioii, and the luel is more uniformlycarhonized. r `"tlllien using air and steam with consequent'partial combustion. in the retort, it found-thatthe retortgases are ata higher temperature than previously possible with pure steam distillation. ,'llhe result oit this` is. that it is now possible to extract the coal dust `trom the retort gases by means oll a `cy clone dustA extractor. Ylt has heen ll'ound that vitl ii.the higher.temperatures the dust can he extracted without. vany apprcwiahle loss ot oil. When using steam alonea considerable quantity .otoil was extraeted with the dust, and the subsequent separation olxr the oil and dust presented inconveniences. ttlincc using thefair and steam methodA ot working, the

oils are. very much more tree l'roiii dust and appear to he ot better quality.` u y.

.It'ivilli` he understood that thoughtheginveiition has been described in detail with rei?- :erence to the ,addition ogt airto steam, the

method isequally applieahle in. the ease oit' heated gaseous.heatingmedia other than superheated steam.` For example, instead olf:

.sirperheated steam (which operates substanliti site higher distillation temperature Within the retort being obtained by the admixture With the inert gas of the correct proportion of air or oxygen to cause the requisite combustion Within the retort. The inert and active gases might be heated to or above the ignition temperature of the fuel either separately or togethen The invention may be carried out in many Ways, the apparatus hereinabove described in detail being an example only of one form that has been found suitable in practice.

W* hat l claim as my invention and desire to secure by Letters Patent is l. A process for loW temperature distillation of carbonizable solid fuel for the recovery of highly volatile oils and the accompanying partial carbonization of the remaining fuel Without gumming, which comprises, partially carbonizing the material bypassing steam and atmospheric air in regulated amounts to an enclosed body of the fuel, having one component of said fluid medium preheated to a teinperati'lre such that the temperature of the mixture of steam and air While being injected is at least as high as the temperature of ignition of the fuel, whereby a portion of the fuel is ignited, and having the quantity of atmospheric air thus admitted limited to that necessary for the combustion of a smallk percentage only of the enclosed body of fuel.

2. A process for low ten'iperature distillation of carbonizable solid fuel for the recovery of highly volatile oils and the accon'ipanying partial carbonization of the remainingl fuel Without gumming, which comprises, partially carbonizing the material by passing steam and atmospheric air in regulated amounts to an enclosed body of the fuel, having the steam which is injected preheated to a temperature such that the temperature of the mixture of steam and air while being injected is at least as high as the temperature of ignition of the fuel, whereby a portion of the fuel is ignited, and having the quantity of atmospheric air thus admitted limited to that necessary for the combustion of a small percentage only of the enclosed body of fuel.

3. A process for lovv temperature distillation of carbonizable solid fuel for the recovery of highly volatile oils and the accompanying partial carbonization of the remaining fuel Without gumining, which comprises, partially carbonizing the material by passing steam and atmospheric air in regulated amounts to an enclosed body of the fuel, having the steam and air preheated to a temperature such that the temperature of the mixture of steam and air while being injected is at least as high as the temperature of ignition of the fuel, whereby a portion of the fuel is ignited, and having the quantity of atmospheric air thus admitted limited to that necessary for the combustion of a. small percentage only of lthe enclosed body of fuel.

t. A process for low temperature distillation of carbonizable solid fuel for the recovery of highly volatile oils and the accompanying partial carbonization of the remaining fuel without gumming, which comprises, partially carbonizing the material by passing steam and atmospheric air in regulated amounts to an enclosed body of the fuel, having one component of said fluid medium preheated to a tempe ature such that the temperature of the n'iixture of steam and air While being injected is at least as high as the temperature of ignition of the fuel, whereby a portion of the fuel is ignited, and having the quantity of atmospheric air thus admitted limited `to that necessary for the combustion of from two to four per cent of the enclosed body of fuel.

5. A process for low ten'iperature distillation of carbonizable solid fuel for the recovery of highly volatile oils and the accompanying partial carbonization of the remaining fuel Without gumming, which comprises, partially carbonizing the material by passing steam and atmospheric air in regulated amounts to an enclosed body of the fuel, having one component of said fluid medium preheated to a temperature such that the temperature of the mixture of steam and air While being injected is at least as high as the temperature of ignition of the fuel, whereby a portion of the fuel is ignited, and having the quantity of atmospheric air thus admitted limited to that necessary for the combustion of less 'than five per cent of the enclosed body of fuel.

In testimony whereof lt aliix my signature.

EDMUND GEORGE WEEKS

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