US2670280A - Method and apparatus for producing combustible gases from powdered fuels - Google Patents

Description

INVENTOR. FF/EDF/(H TOTZEK TOTZEK METHOD AND APPARATUS FOR PRODUCING COMBUSTIBLE GASES FROM POWDERED FUELS Filed Aug. 12, 1948 Feb. 23, 1954 arrow 5y Patented Feb. 23, 1954 UNITED STATES PATNT FFECE METHOD AND APPARATUS FOR PRODUCING COMBUSTIBLE GASES FROM POWDERED FUELS Application August 12, 1948,Seria1No. 43,953

12 Claims.

I The present invention relates in general to the continuous production of combustible gases from .a carbonaceous solid fuel by its reactions with oxygen, or oxygen-enriched air, in which it is in suspension and also with such fluid oxides as steam or carbon dioxide that can react endothermically with hot carbon by the absorption of heat to yield combustible gases; the invention comprehends more particularly improvements of apparatus whereby the above reactions can be simply and efiectively employed for the production of combustible gas while performing the reactions simultaneously but substantially separately in the same gasification chamber.

In .a copending application Serial Number 43,950 filed August .12, 1948, the present inventor has disclosed an improved method and means for the gasification of finely-pulverized solid fuel. Briefly described, that improved method comprises continuously introducing the pulverized solid fuel into a flow of oxygen, or oxygenenriched air under conditions to form a suspension of the former'in the latter, the so-formed suspension being then continuously introduced in the form of a jet into a gasification chamber that is preheated to a temperature that is above the ignition temperature of. the suspension and in which apparatus the suspension is quickly ignited'while surrounded by a concurrently flow- :ing envelop containing steam or another-fluid oxide that can react endothermically with hot carbon to yield, for example, a combustible mixture of carbon monoxide and hydrogen. In the ,gasification chamber, there thus simultaneously exists a central highly-heated zone, wherein there progresses an exothermic reaction, surrounded by an outer zone of lower temperatures and in which an endothermic reaction takes .adapted to assure that the above-mentioned zones of exothermic and endothermic reactions in a gasification chamber are maintained to a .large degree functionally substantially separate,

despite their marginal contacts, so that progress of the exothermic reaction will not be significantly disturbed by reactants of the endothermic zone and that insulation of the walls of the-gasification chamber from the exothermic zone by reactants of the endothermic zone is continuously maintained for protecting the integrity of the said walls from temperatures that could otherwise quickly flux them.

The invention has for further objects such other improvements and such other operative ad- 2 vantages or results as may be found to obtain in the processes or apparatus hereinafter described or claimed.

According to the present invention new and improved apparatus and processes are provided for practising the process of the above-described copending application. Anessential feature of the present invention resides in the special means for introducing into the gasification chamber the steam or other fluid oxide that can react endothermicaliy with hot carbon to produce combustible gases. This improved feature of apparatus comprises an annular nozzle that surrounds the delivery means for jetting the suspension of pulverized solid fuelin oxygen into the gasification chamber and is so formed and arrangedtnat said endothermically reacting reagent .is introduced into the tapered, conical inlet end of the gasification chamber as a whirling, ,hollown-and conically-shaped envelope that at first streams along in conformation with the inlet walls of the gasification chamber as a sort of veil which flows over the surface of the walls in a circular, expanding flow-path that is, in general, at an acute angle to the longitudinal axis of that stream or jet of the suspension of solid fuel in oxygen, which is simultaneously introduced into the hollow portion of said jet of endothermicallyreacting reagent, and fiows substantially concurrently therewith into zones of the gasification chamber having cross-sections of increasing area in the direction of flow of said reactants/In general, the flow-path of the endothermicallyreacting .reagent can be described as sort of hyperbolic whirl just before and after it leaves the annular nozzle.

In the accompanying single sheet of drawings forming a part of this specification and showing for purposes of exemplification ,a preferred apparatus and, method in which the invention'may be embodied and practised but without limiting the claimed invention specifically to such illusof Fig. 1; and

Fig. 3 is an enlarged view of part of the nozale-head shown in Fig. 1 for introducing the endothermically-reacting medium into the gasification chamber of the present invention.

The same characters of reference designate the same parts throughout the several views of the drawings.

The burner-head of the cashier apparatus inposed inside of a cooling-jacket l.

dicated in the drawing shows a portion of an associated reactor-chamber i that is formed preferably by refractory walls 2 and is substan tially conical shape. The wider end of the reactor-chamber i may be connected to a suitable dust-catcher for separating the powdery ash of the consumed solid fuel from the produced gas. Several of these reactor-chamber burner-heads can be connected to a common dust separator, if preferred.

The pulverized solid fuel and the gaseous and vaporous reactants are introduced into the reactor-space l at its tapered end. A preformed substantially homogeneous mixture of the pulverized solid fuel in suspension in oxygen (prepared in apparatus not shown) can be injected into the reactor-space i through one or more delivery pipes 3', as preferred. In the apparatus shown in the figures, three such delivery pipes are dis- Pipe 5 serves to deliver into the cooling-jacket a suitable cooling medium which thereafter flows out of the cooling-jacket through pipe 8 after having circulated over the fuel-delivery pipes 3. The inner end of the cooling-jacket, as shown, forms part of the end wall of the reactor-space i. That end of the cooling-jacket -'l forming part of the end Wall of the reactor-chamber i is surrounded by a refractory member i that forms one wall of the annular nozzle for introducing said endothermically-reacting agent into the reactorchamber; the refractory member '2 is preferably made in one piece. In combination with a surrounding part 8 of the refractory walls 2 of the reactor-chamber, said refractory member "5 forms the annular nozzle 9, of which the discharging end is disposed substantially coaxially with the longitudinal axes of the reactor-chamber i and the cooling-jacket l.

By means of the annular nozzle 9, steam, carbon dioxide, or the like, or mixtures thereof are injected into the reactor-chamber apart from but simultaneously with a mixture of solid fuel and oxygen that is to be gasified. For this purpose, said annular nozzle 9 is communicably connected directly by means of horizontal passages Ilia extending longitudinally of the axis of the reactor and the annular duct ill with a source of a suitable endothermically-reacting reagent that is supplied under pressure through conduit H. The said horizontal passages Illa are structurally an extension of the annular duct in and are formed by rows of spaced but aligned bricks [lib whereby the upper and lower walls of the ducts lta are retained spaced from each other. In this construction, as is apparent from the Figs. 1 and 2, the said ducts Illa are all interconnected with each other at spaced points by other annular ducts H30 which are a counterpart of that duct It which is in direct communication with the conduit ll. Inasmuch as in the operation of the illustrated apparatus, it is preferred to introduce the endothermically-reacting agent at very high temperatures of preheating-not lower than about 1200 C.it is preferred to form the ducts and passages it, Ida, I00 and H in refractory heat-insulating material so as to obviate as far as practical transfer of heat therefrom through the adjacent masonry into the coolingjacket 4 surrounding the pipes for delivering the cooled solid-fuel suspension into the reactorchamber of the gasifier. For preheating the endothermically-reacting gas or vapor, the conduit H at its lower end can be and is, communicably connected with any preferred apparatus for the 4 purpose such as, regenerators, recuperators, and the like.

For many applications of the present improved apparatus, a single jacketed pipe 3, for injecting the fuel-oxygen mixture into the reactor-chamber is suflicient, as hereinbefore mentioned. For larger installations, as shown in the drawing, it may be however advisable to use a plurality of the pipes 3 contained in a common cooling jacket and in such case it is advantageous to dispose said pipes symmetrically in respect of the longitudinal axis of the reactor-chamber. In those instances Where several of the said pipes 3 are employed, it can be of special advantage to arrange another oonduit It in the space between said pipes, said conduit being adapted to inject a small quantity of an endothermically-reacting medium therethrough directly into the reactorchamber, so as to prevent fortuitous accumulation of any ash of the solid fuel on the end of the cooling-jacket 4.

The annular nozzle 5! is fashioned to distribute the infiowing endothermically-reacting gas or vanor as a continuous, moving envelope or curtain around especially the primary exothermic zone of reaction produced by the rapid oxidation of the powdered coal with the oxygen in which it is suspended; the temperatures developed in this exothermic zone are unusually high and would damage the refractory walls especially adjacent the outlets to the fuel-delivery pipes 3, were these walls not protected by said moving, continuous envelope of endothermically-reacting gas or vapor. Furthermore, the coal particles with any residual carbon content that has not been oxidized in the aforesaid zone of exothermic reaction cannot, as they leave the exothermic zone of reaction, be directly deposited on the walls of the reactor-chamber 1 because they must first traverse the envelope or curtain of steam or carbon dioxide, or the like, that is flowing along the walls of the reactor-chamber; during such traversal, at which time they also have a tendency to be carried along with the current of such envelope, the residual carbon of the coal particles reacts endothermically with steam, carbon dioxide, or the like, and is converted into carbon monoxide which further reduces the temperature of the gases in which they are in suspension. The fuel-ash is then itself removed from the reactorchamber still in suspension in the mixture of gases or vapors resulting from the diffusion of products of the endothermic and exothermic zones of reaction into each other.

The said nozzle 9 is especially designed to deliver the endothermically-reacting fluid into the reactor-space as whirling, hollow and conicallyshaped flowing envelope. The suspension of powdered fuel is injected into the hollow portion of this envelope where it immediately ignites a short distance from the discharge ends of the delivery-pipes 3 and partially oxidizes the carbon content of the fuel. One of the principal reasons for giving the gaseous or vaporous envelope the described configuration is to avoid too early a diffusion of the endothermically-reacting fluid into the exothermic primary zone and to delay such difiusion until substantially all of the oxygen therein has been used for oxidation purposes. Too early mixing of the endothermically-reacting fluid with reactants of the exothermic zone would have a deleterious efiect on the progress of the gasification; i. e., it would dilute the employed oxygen, unwanted- 1y reduce the temperature otherwise attainable in the exothermic zone and importantly reduce the efiiciency of the gasification process.

As already mentioned, the walls of annular nozzle 9 are formed by the refractory bricks 8 of the reactor in combination with the refractory member 5 of the burner head that is shown in enlarged view in Fig. 3. The outer surface of the member I is formed substantially as a cone and is provided with a central orifice through which can be inserted the cooling-jacket for the fuel-delivery pipes s. This central orifice should preferably be of such diameter that under operating conditions there is contact between said cooling jacket and the walls of said central On the outer conical surface of the refractory member 1 there is disposed in the channel of the annular nozzle 9, an annular series of parallel spaced. ribs or projections 2, that, because of the incline of this conical surface 1, are at their bases also inclined slightly toward the center of the reactor-chamber; in addition, these projections are also set at an acute angle to the axis of the central orifice of the refractory member l, and in a direction that their extensions radiate in a direction away from and offcenter to the center of the reactor-chamber I These ribs or projections terminate short of the outlet end of the nozzle 9, and subdivide the annular channel of nozzle 9 into a plurality of small passages or ducts that cause endother mically-reacting fluid that passes through them to be discharged with a spiral initiating motion and on lines at an acute angle to be directed away from the longitudinal axis of the reactorchamber I, and thus peripherally as the steam i issues through the outlet end of nozzle 9, instead of axially toward the axis of the reactor chamber, whence the steam assumes the form of an expanding hollow cone that moves along that conical surface of the reactor-space adjacent the burner nozzle since, as known, the outer periphery of the nozzle 9 is the terminal of the inner surface of the narrower end of the conical reactor space I, which latter flares away from the nozzle 9. and radiates away from the axis, along the enlarging area of the reactor space in a spiral motion, as the solid fuel suspension flows axially along the reactor space, as they both are issuing into the reactor chamber in spaced relation to each other. The fluid continues with this spiral motion throughout its travel from the annular nozzle to the wider end of the reactor-chamber and eventually to the dust separator connected therewith. The conical mantle of the endothermically-reacting fluid is thus prevented from penetrating the central zone of the reactorchamber and thereby interrupting or penetrating the zone of the exothermic reaction.

The gasifier apparatus of the present invention makes possible continuous production of combustible gas having high concentrations of carbon monoxide and also of hydrogen from finely divided solid fuel. It can also be advantageously and similarly used for the gasification of liquid fuels.

The invention as hereinabove set forth is embodies in particular form and manner but may be variously embodied within the scope of the claims hereinafter made.

I claim:

1. Gasification apparatus for the continuous gasification to combustible gas of carbonaceous fuel contained in a suspension by exothermic and endothermic reactions that are conducted in Hence, the steam flow discharges 6 generally separate zones having direct margin] contact with each other. said apparatuscomprising a gasification chamber, inlet conduit means disposed axially of said chamber at one end thereof and adapted to inject continuously a preformed suspension of carbonaceous fuel in a free-oxygen-containing gas in the formofa jet axially into said gasification chambenannular conduit means arranged coaxially with said inlet conduit means in surrounding relationship therewith and gas-directing meansdisposed in said annular conduit means for directperiphery of said axial jet and moving cocurrently therewith to form a continuous whirling enveloping layer of said fluid oxide between said jet and the wall of said chamber.

2. The apparatus of claim 1 in which the inlet conduit means is provided with a cooling jacket so disposed as to have a surface thereof contiguous to the discharge end of said inlet conduit means said surface forming a boundary wall of said gasification chamber.

3. The apparatus of claim 2 wherein a plurality of inlet conduit means are contained Within said cooling jacket.

4. Gasification apparatus for the continuous gasification to combustible gas of carbonaceous fuel contained in a suspension by exothermic and endothermic reactions that are conducted in generally separate zones having direct marginal contact with each other, said apparatus comprising a gasification chamber, an inlet conduit means disposed axially of the chamber at one end thereof and adapted to inject continuously a preformed suspension of carbonaceous fuel in a free-oxygen-containing gas in the form of a jet axially into said gasification chamber, annular conduit means arranged coaxially with said inlet conduit means in surrounding relationship therewith and gas-directing means disposed in said annular conduit means for directing a flow of a fluid oxide, capable of reacting endothermically with carbon, tangentially to said jet and along the inside wall of said chamber and around and longitudinally along the periphery of said axial jet and moving cocurrently therewith, to form a continuous whirling enveloping layer of said fluid oxide between said jet and the wall of said chamber, the walls of said gasification chamber at the end adjacent to said inlet conduit means being tapered toward the longitudinal axis of said chamber.

5. The apparatus of claim 4 in which the annular conduit means comprises an inwardly converging annular nozzle.

6. The apparatus of claim 5 in which the inwardly converging annular nozzle is divided into a plurality of channels by ribs projecting outwardly from the inner surface of said nozzle, said ribs having their walls disposed at an acute angle to the axis of said nozzle.

7. The apparatus of claim 6 in which the ribs are located intermediate the inlet and discharge ends of said nozzle.

.8. The apparatus of claim 7, in which the nozzle is provided with longitudinal passages between said ribs and said inlet end.

9. The apparatus of claim 8 in which said longitudinal passages are interconnected. of said 10. A process for the production of a gas containing carbon monoxide which comprises forming a, suspension of a finely-divided solid carbonaceous fuel in a free-oxygen-containing gas at a temperature below the ignition temperature of said fuel in such proportion that only a part of said fuel will react exothermically with the oxygen of said gas, introducing said suspension as a jet axially into a reaction chamber maintained at a temperature above the ignition temperature of said fuel, thereby subjecting said part m of said fuel to combustion, and introducing annularly, coaxial with and surrounding said jet a stream of endothermic gasifying agent to form a continuous whirling enveloping layer of said thermic gasifying agent is steam.

8 12. The process of claim 10 in which the endothermic gasifying agent is carbon dioxide.

FRIEDRICH TOTZEK.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 1,513,622 Manning Oct. 28, 1924 2,302,156 Totzek Nov. 17, 1942 2,311,140 Totzek et a1. Feb. 16, 1943 2,344,007 Totzek Mar. 14, 1944 OTHER REFERENCES Flat Final Report 1303 (P385165), Koppers 15 Powdered Coal Gasification Process," by Harold V. Atwell, pages 12, 14, 15, 16, 19, 20, 21, 22, and 23 Joint Intelligence Objectives Agency, Washington, D. C. Sept. 2, 1947.

Claims (1)

10. A PROCESS FOR THE PRODUCTION OF A GAS CONTAINING CARBON MONOXIDE WHICH COMPRISES FORMING A SUSPENSION OF A FINELY-DIVIDED SOLID CARBONACEOUS FUEL IN A FREE-OXYGEN-CONTAINING GAS AT A TEMPERATURE BELOW THE IGNITION TEMPERATURE OF SAID FUEL IN SUCH PROPORTION THAT ONLY A PART OF SAID FUEL WILL REACT EXOTHERMICALLY WITH THE OXYGEN OF SAID GAS, INTRODUCING SAID SUSPENSION AS A JET AXIALLY INTO A REACTION CHAMBER MAINTAINED AT A TEMPERATURE ABOVE THE IGNITION TEMPERATURE OF SAID FUEL, THEREBY SUBJECTING SAID PART OF SAID FUEL TO COMBUSTION, AND INTRODUCING ANNULARLY, COAXIAL WITH AND SURROUNDING SAID JET A STREAM OF ENDOTHERMIC GASIFYING AGENT TO FORM A CONTINUOUS WHIRLING ENVELOPING LAYER OF SAID ENDOTHERMIC GASIFYING AGENT BETWEEN SAID JET AND THE WALL OF SAID REACTION CHAMBER.

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