US418275A - cornell - Google Patents

Description

(No Model.)

El Bl GURNELLI ZSheets-Sheet 1. MET'HOD 0F HEATING 1N FURNAGES. No. 418,275.A Patented 13630.31, 1889.

(No Model.) l 2 sheets-sheet 2.

' RB.' CORNELL. METHOD V01?' HEATING IN FURNABS. No. 418,278 'Patented D96. 31, 1889.

W'ITNESSES:

UNITED STATES PATENT rrlcn,

ELIJAII CORNELL, OE PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO TI-IE NATURAL GAS FUEL COMPANY, OF SAME PLACE.

METHOD OF HEATING IN FURNACES.

SPECIFICATION forming part of Letters Patent No. 418,275, dated December 31, 1889.

Application filed October 9, 1889. Serial No. 326,476. (No model.)

To all whom, it may concern:

Be it known that l, ELIJAH B. CORNELL, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Methods of Heating in Furnaces or Analogous Devices, of which the following is a specification.

My invention relates particularly to im Io proveniente in that branch of the art in which heat is generated through the agency of steam injected into or through the fuel.

IIeretofore it has been customary to increase the heat obtainable in a furnace byincreasing the consumption of fuel with relation to a given size of furnace. This increase of consumption has been effected by increasing the draft or supply of" oxygen in various manners. That manner more nearly con zo nected with my improved method has consisted in injecting steam and air upon the fuel, dry steam being preferably employed. This is a method of dissociating steam in which the action of the steam upon the fuel 2 5 is to part with its oxygen to the carbon of the coal or other fuel or to the carbonic oxide formed from such fuel, setting free the hydro* gen, which is burned at the expense of indrawn atmospheric air. Such a method is 3o wasteful of the heat-units obtainable from the steam for several reasons, among which I cite the following.

It is well known to chemists that on account of its great specific heat hydrogen has a com- 55 paratively enormous cooling effect. The increased combustion of fuel, therefore, caused by the separation of the oxygen and its combination with the carbon of the coal or other fuel, although giving greater amount of heat,

does not result in full advantage of that greater heat, as that heat is practically dissipated in heating the hydrogen evolved. The heat, therefore, that results is not the sum to tal of the heat obtainable from the combustion of the constituent gases of steam between themselves, but is a differential sum of the heats of combustion of the hydrogen in atmospheric air and the heat evolved from the combustion of the extra fuel less the heat lost from the latter combustion by the heating of the volume of hydrogen evolved. Thus, while in a furnace so heated it is undoubtedly possible to obtain greater heat than by a plain fire,

it is only possible to obtain this greater heat by the consumption of a greater amount of fuel. lVhile it is true that an economy may appear to be effected by the possible use of a cheaper fuel, the larger amount of the cheaper fuel consumed results in no actual economy, and this is probably the chief reason why after 6o lengthy trials these methods are generally discontinued.

Another method of dissociating steam consists in causing that vapor to pass over iron or similar material that will absorb the oxygen, setting free the hydrogen, that can be used as fuel.

I am aware that such processes are known and have been extended in the arts as regenerative processes, by which the oxygen ab- 7o sorbed has been caused to be given up from the material through the application of greater or less heat. A layer of silver has been used in this way, which when molten absorbed the oxygen of steam passed over it, but which when cooled gave up the oxygen. I mention such process particularly to show that I disclaim it as having only a prima facie similarity with what I shall subsequently describe as my new method. All of these processes in 8o which dissociation occurs as the result of the affinity of a fuel or fuel material or other substance for one of the constituents of steam I consider to be wasteful, for the reasons I 'have given, and for the further reason that 85 steam, when separated into its constituent gases-oxygen and hydrogen-then consists of those gases in such proportion, each relatively to the other, as will by their recombination develop the greatest amount of heat 9o obtainable from water as a primary source.

Iwill now explain that by the term dissociation of steam by heat I mean that steam is resolved into its constitutents by the loss of one of them through satisfaction by that 9 5 constituent of a chemical affinity, and that generally to this loss is due a lesser heat than is obtainable by the combustion of hydrogen in oxygen; but I term that decomposition or resolution of steam into its constituent gases 1c J by heat Withoutl loss of either constituent gas, (in satisfaction of chemical aifinity,) producingan oxyhydrogen gaseous mixture, thermolysis,V and the effecting of thermolysis I term thermolyzing. By thermolytic action upon steam passed through platinum and porcelain tubes, Grove, also Deville, has shown that this vapor may be resolved into its constituent gases, and an attempt to utilize this principle in the production of poiver has been described in the English Patent No. 4,386 for the year 1876. Imake use of this principle in my invention, and I have discovered that steam passed through a cast-iron tube maintained at or above the temperature of molten silver is decomposed into its constituent gases Without oxidation of the tube. I have further discovered that this action cannot be obtained With plain Wrought-iron tubes, for the reason that the wrought-iron tube is oxidized at the expense of the oxygen of the steam in so short a period of timeas to render plain wrought-iron tubes practically `useless. .I advance the theory that the eastiron tubes are rendered inattackable by the oxygen, for the reason that litbecomes coated with a stratum of carbide of iron, or, more probably, of a carbo-silicide of iron. I also advance as a theory explaining this fact that hot Wrought-iron is more easily oxidized than is hot cast-iron7 because of its position in the electro-motive scale being more positive than that of cast-iron. According to my invention, having caused the decomposition of the steam into its constituent gases by the action of thermolysis in a heated cast-iron tubular retort placed, preferably, in the hottest part of the furnace, (which furnace is employed to generate the steam to be passed through the tubular retort and therein submitted to thermolysis, or which steam may be obtained from a foreign source,) I cause the gases to pass into the closed ash-pit situated beneath the grate-bars or their equivalent in the furnace. If these grate-bars support a fuel-such as coal-requiring oxygen for its consumption, I supply that oxygen by causing the gases, as they fioW with their great initial pressure from the exit-tube of the retort, to inject or induce into the ash-pit thel quantity of air necessary to the consumption of the fu el Without any regard to the heat to be obtained from the consumption of the oxyhydrogen gaseous mixture. I Wish it to be fully understood that I consider that the heat obtained from the consumption of the oxyhydrogen gaseous mixture resulting from the thermolyzing of the steam in the castiron tube or retort is Wholly additive to the heat obtained from the combustion of the fuel by the `injected or indrawn air, which air I consider in no Way a diluent of the oxyhydrogen gaseous mixture; but I further have discovered that the action of the fuel lying on the grate-bars, so far as relates to the combustion of the oxyhydrogen gaseous p mixture, is a catalytic or contact action-that is, the gases will not, at the pressure and Velocity at which they issue from the injector, ignite, and even When reduced in velocity and pressure, so as to become ignitible, they then ignite only as an explosive mixture, the explosion causing discontinuance of the inflammation. It is, I believe, Well known in chemical science that an explosive gas-mixture cannot be burned continuously or With a continuous flame. Now I have discovered that if such gases resulting from the thermolyzing of steam be passed through the ashes of coal these ashes have such an action at a proper temperature 'as to cause the continued inflammation of the oxyhydrogen gaseous mixture, and as the ashes are not consumed, nor does it appear necessary that they should be, at a temperature likely to maintain in Ham mation by presenting a sufficientlyheated substance to cause continuously inlinitesimal explosions, which, as a Whole, might appear to be cont-inuous iniiammation, I have concluded that such action is a contact or catalytic action. More especially have I been forced to this conclusion by the reason that asbestus affords a material which will, by passing the oxyh yd rogen gaseous 'mixture through it at a temperature below that required to initially in flame such mixture, maintain constant inflammation. I base my opinion that this operation is catalytic on other experimental facts, and I Wish it understood that Whatever' may be the nature of this action I find such catalytic material necessary in practice to the continual inflammation of the gases.

I will now further describe my invention by considering the process as completed by the joint combustion of the coal under the action of atmospheric air, together with the combustion of the oxyhydrogen gaseous mixtu re, which combustions I consider separate but simultaneous operations, until the carbon of the coal becomes exhausted, When I may and do, if I so prefer, cause the continued combustion of the oxyhydrogen gaseous mixture to maintain the heat of the furnace. Thus by my invention practically great economy is effected, and I am enabled to support combustion at the expense of the cheaper fuel water with a minimum amount of the more expensive f uel-coal-Which I consider may be reduced to that necessary to provide a layer of fresh ash, including that requisite to afford a means of reigniting the gaseous mixture, When its current has been interrupted, for the reduction of the temperature for any required purpose-such as the reduction of steam-pressure-should the furnace be employed in the heating of a boiler. Although I have described the injection of the gases into the ash-pit as taking place below or beneath the grate-bar supporting the fuel material, I Wish it understood that I consider this material and the grate-bars merely as a septum and its support, the septum having the catalytic action necessary to the opera- IOO IIO

tion of continuous inainmation of the oxyhydrogen gaseous mixture. By my invention very nearly absolutely perfect combustion is attained, evidenced by the transparency of the iiame burning above the layer of fuel material upon the grate-bars, this transparency being such as will render visible the firebridge in a furnace several feet in depth. NVitli` such nearly-complete combustion a smoke-stack may be dispensed with, and the omission of so expensive constructive work is a secondary advantage of my method.

In orderthat those skilled in the art may practice my improved process, I will now describe the preferred apparatus which I use.

Referring to the accompanying drawings, Figure 'l is a sectional elevation of a form of furnace equipped with a form of devices for practicing my invention, said devices comprising a catalytic septum in itself either a fuel, or not a fuel, a steam-supply pipe from a distant source of supply, a superheater or drier, a retort, and outlet-pipe from the retort leading beneath the catalytic septum or mass. Fig. 2 is a like view,partiallyperspective, showing a fuel catalytic mass or septum, and, further, an air-injector connected with the retort outlet-pipe for causing the gases from the retort to inject or induce air into the ash-pan or below the catalytic mass or septum. Fig. 3 is an elevation of a preferable form of retort, drawn to an enlarged scale. Fig. 4 is a side view of preferable form of inj ector for use with my improvements; and Fig. 5 is a sectional elevation, partly in perspective, of a furnace and adjacent stationary boiler equipped with devices for practicing my invention.

A represents a form of furnace for any preferred purpose, composed of lire-box B, having grate-bars l), ash pit or chamber C below said grate-bars, in which is located a pipe or injector C', having connection c with a retort- D, located within the tire-box, preferably in such position that it is subject to the heat thereof, which, while it is hot enough to cause it to convert steam into its constituent gases by thermolysis, as before described, is not sufficient to fuse or otherwise deteriorate the retort. In the form of furnaces shown in the drawings said retort is indicated as located beyond the bridge-wall. Said retort, therefore, in some furnaces, like those for stationary, locomotive, and other boilers, will be locatedin the hottest part of the furnace, as the heat therein is not usually sufiicient to fuse the retort, whereas in smelting or other like furnaces the retort will be located without the field of the most intense part of the heat of the furnace; or, if located within said field, the retort will be suitably shielded or protected against the most intense heat, so as not to fuse.

The retort D may be of any suitable form. In practice l use a cast-iron retort of the U shape, as shown, which is of a larger area in cross-section within certain proportions than vapor, which will be carried forward with the gases and act detrimentally. The interior of the retort is preferably lined or caused to be lined in any suitable manner with carbide of iron or carbo silcide of iron to render it inoxidizable and avoid dissociation by afnity, as hereinbefore set forth.

Any suitable form of injector C may be used, a preferable form which I use in practice being that shown, described, and claimed in United States Letters Patent dated 'October 30, 1883, No. 287,754. The grate-bars h' may be constructed, as desired, of any suitable material. ()n these grate-bars is placed any suitable catalytic material b2, forming what I have termed a septum for acting on the constituent gases of the decomposed steam as they pass through the same. In practice for steam-boiler furnaces I use theifuel or coal as a catalytic material or septum, as it subserves the purpose of initially generating the steam and initially inliaming the gases and maintaining constant inflammation.

If the steam-boiler d is located adjacent to the furnace and the steam therefrom is dry,

-into that retort in which it is thermolyzed.

Vhen fuel or coal is dispensed with as a catalytic material, the injector C need not then be used, in which case the outlet-pipe c from the retort is led directly into the ash-box or equivalent chamber, and may terminate in a downwardly-turned end, as desired and as indicated by dotted and full lines, Fig. l.

The practice of my improved method with the above-described apparatus is as follows: The catalytic material in the fire-box is first ignited or heated to initially generate steam and heat the retort D or retort and superheater or drier D in the fire-box, if the boiler cl is adjacent thereto, and to heat the retort D or such retort and superheater or drier D only, if the steam-supply is brought from a distant location. The dry steam entering the retort D is by thermolysis decomposed into its constituent gases, which pass through the injector when used, or through the continuation of pipe c when the injector is not employed, .and enter the ash pit or chamber below the grate-bars b. The gases as they pass through the catalytic material are acted upon andburned as hereinbefore stated.

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While the method above disclosed is practical with either forni of apparatus Which I have shown and described, I Wish it tov be distinctly understood that I do not limit myself to the use of this specific mechanism, it being within the scope of my invention to practice my method with any apparatus adapted for its correct vWorking and for obtaining the result which I attain.

I Wish it to be understood also that while I have described the retort D, or such retort and superheater or drier D', as made preferably of cast-iron, I do not limit myself to this material, but design that the claims directed to this feature shall be of such generic nature as to include any non-oxidizable materialthat is to say, any material not readily attacked by the liberated oxygen during thermolytic action above described.

I do not herein claim the above-described apparatus, as it forms the subject-matter of a separate application filed by me November 29, 1889, Serial No. 331,897.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, 1s-

l. The method of heating in furnaces which consists in thermolyzing steam into its constituent gases and th en subjecting these gases to catalytic action and combustion, substantially as set forth.

2. vThe method of heating in furnaces which consists in forming steam, converting such steam into an oxyhydrogen gaseous mixture,

subjecting such gases to catalytic action and combustion, substantially as set forth.

4. `The method of heatingin furnaces which consists in forming steam, drying this steam, superheating it, converting it into an oxyhydrogen gaseous mixture, distributing this gaseous mixture through a catalytic mass, and burning said gaseous mixture, substantially as set forth. l

5. The method of heating in furnaces which consists in thermolyzing steam intoits constituent gases and subjecting such gases to the action of a catalytic mass in itself a fuel, and to combustion simultaneously with this fuel, air being supplied to such fuel to support its combustion, substantially as set forth.

6, The method of heating iu furnaces which consists in th ermolyzing steam into its constituent gases and subjecting such gases to the action of a catalytic material in itself afuel,

and to combustion simultaneouslv with this fuel, air being supplied to such fuel to support its combustion by injection by said gases, substantially as set forth.

7. rlhe method of heating in furnaces Which consists in thermolyzing dry or superheated steam into its constituent gases, distributing these gases beneath the grate-bars of a furnace, subjecting them to the catalytic action of a material, whether it be itself a fuel or not, and which material is situated above the grate-bars, and consumingby combustion the gases in and above said material having a catalytic action, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

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