US1918739A - Gasification apparatus - Google Patents

Description

y 13, 1933- w. B. CHAPMAN GASIFICATION 'APPARATUS Filed July 30, 1929 INVENTOR AT ORNEYS Patented July 18, 1933 PATENT OFFICE i mm! a. crumun, or ucxson mnenrs, new YORK easnuca'non .arrm'rus 1 application fled m ao,

The invention relates to the low temperature carbonization or distillation of coal or other solid fuel containing volatile h drocarbons as a preliminary step employe I in con- 5 junction with the complete consumption of fuel, the final step preferably being the manufactureof producer gaswhich'gas, if desired, may beimmediately burned after leaving the firebed, for boiler heatin or other analo ous purposes, and for provi ing additional eat for acceleratin said preliminary step;

One object o the invention is'to enable the low temperature distillation of fuel to be carried out under improvedheating conditions,

the invention makln it'possible when itsfeatures are utilized in ull, to obtain gas by low temperature distillation which is rich enough to go into city mains, and the low temperature distillation being carried out in a zone wherein the gas and heat made available by thefinal, step of complete gasification are efficiently utilized. Gasesdistilled oifat low temperatures may also be obtained which are substantially undiluted with leanor inert "gases while simultaneously the fuel is completely gasified leaving no coke residue for which Jamarket would have to be found, Further objects and advantages vofthe invention will be in part obvious and in partspecifically pointed out in the description hereinafter contained which,

taken. in conjunction with the accompanying drawing, discloses an apparatus adapted to be operated in'accordance with the invention.

This disclosure, however, should be understood as being merely illustrative of the princi les of the invention. In the drawing-'- ig. 1 iS a vertical sectional view taken through an apparatusadapted to. be operated in accordance with the invention.

F Fig. 2-is a section taken on line I accordance with the present. invention the preparatory step of lowtemperature distillation is carried out in a preheating or dis- 'tillation'zone of a firebed substantia ly concentric with the combustion zone wherein the final step of complete gasification takesplace whereby the coal fed to the first zone is hea uniformly, b thesecond firebed zone and the 59 gas produce in the latter. Preferably the 1m. Serial no. saaaaai, 1

fresh coalis fed into the central zone of a firebed, in such manner thatafter the preparatory step of low temperature distillation has taken place therein, the coal then passes to an anular zone of the firebed surrounding the first mentioned zone and in close contact therewith, making it possible to draw ofi the low temperature distillates from the central zone of the firebed without substantially mixa ing therewith the producer as generated in thesurroundlng zone of the ebed. I prefer also to employ an underfeed of coal, and take oil the low temperature distillates downwardly from the -central distillation zone of the firebed, as is hereinafter described in greater detail. It should be understood also that the above mentioned firebed zones may be employed in installations wherein the final step of gas'ification involves com lete combllStlOIl'Of the fuel in the firebed, a though, as

' above stated, particularly where the low temperature distillate is desired to be obtained substantialy free from dilution, I prefer to employ a deep firebed which will generate producer gas. But whether the combustion be only partial, thus making producer gas, or

complete,nocoke residue is contemplated.

In the apparatus illustrated in Fig. 1 the firebed enclosing walls 1, which may ave a water-cooled lower section 2, are supported by a suitable number of pedestals 3, and a rotatable pan 4 having gear teeth 5 for engagement with'any suitable driving gear or the like (not shown) underlies the firebed, the pan bein carried by the rollers 6 extending-from pe estals'3'. A hollow skirt or base 7 depends from the sidewalls into pan 4 in such manner as to form a water-seal with the latter, and as shown air is supplied to the firebed through a pipe 8 leading to an annular air distributing chamber 9 within skirt 7, the air passing into the lower ortion of the firebed through a suitable num r of narrow grate openings 10 and ll in the inner wall.

of skirt 7. The conical shape of the base'or skirt 7 provides a stationary support beneath a sufiicient pm of the firebed to prevcnt'the latter from turning around with an 4.

Fuel isfed into the central or d zone of the firebed from hopper 12 by a.horiistillation gressively passes and travels downwardl un-- til the ash is ejected from pan 4 throng the water-seal and over the edge of the pan in any suitable manner as by a conventional as plow (not illustrated).' Hopper 19 is constructed either of special heat resisting metal as shown, or it may be water cooled.

A suitable number of firebed agitating arms 20 may be carried by the pan 4 and rotated through the ashes in the bottom portion of the firebed to break up clinkersandclose up blowholes and assist in maintaining uniform conditions of fuel consumption in said peripheral zone, and also assist in stroking the ash downwardly to an 4*and throu h the water seal, the firebe as a whole being held against rotation by the sidewalls 1, skirt 7, casing 16 and ho per 19. a

The hopper 19 guides fuel outwardly to some extent, and tends to prevent producer gas from readily reaching the outlet for the low temperature distillate's.

As the incoming fueltravels through the firebed z'one defined by he per 19, casing 16 and feed screw pipe 14, suc fuel will besubjected to the heat ofthe surrounding firebed zone, in which latter the consumption ofthe fuel is completed by the air blast from chamher 9, this relation of parts serving-to heat the incoming fuel evenly all the way around the walls of casing 16 and hopper 19 and in addition the gases issuing from the peripheral zoneof the firebed are free to play over or be burned over the top surface of the fuel supported by casing 16 and hopper 19, low temperaturedistillates being thereby driven off from the fresh fuel before the latter asses to the peripheral zone ofthe firebed. sually distillates up to about 950 F. will be driven oil in the above manner, after which the residual fuel passes to the peripheral zone of the firebed, and as 'abovestated I prefer to maintain a deep firebed in such peripheral zone, thereby making gasof the producer gas type in the latter. Producer gas so-obtained, it should be understood, may be either immediately burned in admixture with secondary airthereby increasing the low temperature gasifying capacity of the equipment, or conducted off from the space above the surface of the firebed, as desired.

The low temperature distillatesdriven off during the first stage of gasification which takes place Within the central zone of the firebed as above described, may be se arately drawn off into the ipe or hollow s aft 14 through orts 21 isposed in the wake of travel of t e helical blade 18, so that the ratetion of said'blade keeps the fuel away from said ports and thus prevents them from be coming clogged. The low temperature distillates then are conducted away'preferably through an off-take pipe 22 leading from the interior of the feed screw member 14 and preferably forming a liquid-sealed connection with the latter, the liquid being held in container 23 underlying member 14. From thence the gas is piped to the cooling and cleanin apparatus.

The el delivered at the top of vertical screw 18 is preferably directed upwardly to some extent by an inclined blade 24 rotating with member 14 and provided with a scraper 25 acting on the surface of hopper 19 to clean the same and to keep the fuel moving 4 outward. While. for convenience the entire fuel bed is referred to herein as a firebed, it should be understood that actual (partial) combustion of the fuel is limited to the outer annular zone to which oxygen is supplied.

I prefer also to provide a further rotatable agitatin member 26 operating in the top surface of t e firebed to stroke the fuel outwardly, and level out the top'surface of the firebed to someextent and also to prevent blowholes and to maintain as far as possible uniform density throughout the contents of the central distillation zone. The prevention of channels in the central zone is 'of the utmost im ortance, since channels would cause the ric gases in the central zone to be diluted by the drawing in of a portion of the low value gases surroundin said a zone. The need for adequate agitation is therefore apparent. In the illustrated form of the invention, this agitating member 26 rotates concentrically within fuel feed member 14 although at a different speed and has a plate 27 which overlies and closes the bearing inthe top of the member 14- and is scraped clean by the up-stroking blade 24, the a itating member 26 being dnvenby a gear 28 fixed to the lower end of its stem 29, said gear 28 bein engaged by a drivin pinion 28a. The fuel eed member 14' is il ustrated as rotated by a similar gear 30 connected to its lower portion, and engaged by a driving pinion 31. f'desired, a certain amount of low grade oil or tar may be mixed in with the fuel fed to the apparatus, particularly if the latter is desired to be enriched or to have a large overload capacit ,low temperature distillates being'obtained therefrom in the same manner as above described, and the residium passin alon with the fuel to the second stage 0% gasi cation."

While-the invention has been described as carried out by aspecific apparatus, it should be understood that many changes may be made without departin from its essential features as set forth in t e appended claims.

I claim:

1. An apparatus for asifying fuel, having firebed enclosin wal s substantially symmetrically dispose with regard to a central vertical axis means for feeding air to an annular zone in the firebed, a fuel underfeed device operating substantially concentrically with said axis for feeding fuel to the central ortion of the firebed, and an off-take pipe or low temperature distillates, also disposed substantially concentrically with regard to such axis, and leading downwardly from the central portion of the firebed.

2. An apparatus for gasifying fuel, having firebed enclosing walls substantially symmetrically disposed with regard to a central vertical axis, means for feeding air to an annular zone in the firebed, a fuel underfeed device operating substantially concentrically with said axis for feeding fuel to the central ortion of the firebed, and an off-take (pipe or lowitemperature distillates enclose y said fuel feeding device. 3. An apparatus for gasifying fuel, having firebed enclosing walls substantially symmetrically disposed with regard to a central vertical axis, means for feeding air to an annular zone in the firebed, a fuel underfeed device operating substantially concentrically with said axisfor feeding fuel to the central portion of the firebed, and an off-take pipe for low temperature distillates also disposed substantially concentrically with regard to such axis and leading downwardly from the central portion of the firebed, said fuel feeding device having a fuel agitating member operating adjacent said off-take pipe.

WILLIAM B. CHAPMAN

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