US2580179A - Apparatus for vaporizing heavy liquid fuels - Google Patents

Description

Dec. '25, 1951 Filed April 6, 1951 2 SHEETS-SHEET l Figi nvenrs A. Le Coe/1f H. Gul/fon '1,3 'R Roubl'nef' v Dec- 25, 1951 A. LE coN'T ETAL APPARATUS FOR VAPORIZING HEAVY LIQUID FUELS 2,58og179 j 2 SHEETS-SHEET 2 Filed April 6, 195]:

Patented Dec. 25, 1951 APPARATUS FOR VAPORIZING HEAVY LIQUID FUELSy v Albert le Cont, Henri Guillon, and Ren Rou-V binet, Paris, France, assignors to the Socit Anonyme so-called: Oice Central de Chauffe Rationnelle, Paris, France i Application April s, 1951, seria1N0.219,73s

v In France April 3, 1950 2 claims. l

This vinventionI relates` to apparatus for the combustion of liquid fuels.

Normally, in the combustion of fuel oil, the oil is rst subjected to atomisaticn, either by a fluid under pressure, e. g. air or steam, or rnechanically, yor by the two in combination. From the fuel oil burner there is then emitted a mist of very minute droplets of fuel, usually admixed with air, so that the combustion, once initiated, is capable of proceeding without further outside action of the mist thus discharged from the burner. rThe combustion process is extremely rapid, vand it is indispensable that it should be completed before the droplets reach the end of their path within the combustion chamb-er.

In the case of tars and heavy fuel oils the preheating and atomization of the fuel do not overcome the necessity f-or very rapid combustion, as the droplets cf oil are liable to burn if they are maintained in the midst of an `oxidizing and very hot flame, this, therefore, involving a short ame and a very rapid combustion, so that the heating effect is unavoidably rough. When these requirements are not fulfilled, due either to premature cooling or to the supply of air beingtoo small, soot will form and will be deposited on the parts of the mechanism. More particularly, it is not possible to obtain a long and waving iiame of a neutral or reducing character combined with the generation of carbon monoxide and free hydrogen Without the formation of considerable amounts of carbon black, the presence of which is objectionable, if not altogether harmful. The deposits 'result from a cracking yof the heavier hydrocarbons which attends, and in most cases even precedes, the complete combustion.

It is the primary object of the present invention to provide apparatus for the combustion of liquid fuels, wherein these disadvantages are avoided.

The invention, therefore, resides in a method of effecting combustion of heavy liquid fuels, such as tars and fuel oil, characterized in that the liquid fuel is first converted completely into a gaseous mixture composed primarily lof carbon monoxide ancl hydrocarbons by incomplete combustion `thereof with the requisite amount of preheated air or other combustion-sustaininggas, whereupon combustion of the mixture is completed by any known method.

The liquid fuel may be preheated and injected, in the form of liquid `filaments, together with preheated air into a furnace having refractory walls. In this case the air may be injected immediately adjacent the liquid filaments. 4

Air intakes may be sc arranged that streams of air issuing therefrom sweep those portions of the furnace in which the carbon released by the conversion of the fuel has a tendency to settle.

In an alternative form of the invention the liquid fuel may be trickled in the'form of a thin layer along surfacesin contact with gases or vapours,l which are caused to flow in opposition to the direction of iiow of the liquid fuel. A The invention also resides in a furnace for use in carrying out the method in question, the furace having a refractory lining, at least one set of concentric tubes comprising a central tube for the introduction of liquid fuel and an outer tube forming together with said central tube an annular space for the introduction of z air, and air inlet nozzles for directing streams of air towards that portion of the furnace on which the fuel Vintroduced into the furnace impinges. In a specific form of embodiment the furnace may be provided, in the interior, with a system of superimposed horizontal baflies, along which the liquid fuel is allowed to trickle in opposition to a combustion-sustaining current Iof gas ascending in a zigzag path between the vsaid baifles. Three examples illustrating the manner in which the invention can be'carried into eiect will be described in the following with reference to the accompanying drawings, in Ywhich Fig. 1 is a vertical section of a furnace adapted for. carrying outa first embodiment of the lnvention.

Figs. 2 and 3 illustrate a furnace employed in a second embodiment of the invention, Fig. 2 being a vertical section taken on the line 2-2 in Fig. 3, and Fig. 3 being a horizontal section taken on line 3-3 in Fig. 2. i

Fig. 4 is a vertical section of a furnace suitable for carrying out a third embodiment of the in# vention.

According to the iirstexample illustrated in Fig. l, there is employed a producer comprising a furnace l, which is composed of a refractory material. Preferably, the form of said furnace is that of a vertical cylinder; It is provided at its lower end with an orince 2 for use in heatingl the furnace l to the desired temperature by means of an auxiliary burner or other known device. The fuel oil is preheated toa comparatively high temperature, which, however, is less than that at which cracking commences. It is then supplied by a pipe 3 and fed into the furnace l through a tubev G surrounded by an annular duct l. Hot air or, for example, pure oxygen is fed to thevintakeA 4 vof the anular duct 1. A pair of nozzles 5 serve to supply further amounts of air for apurpose to be described later. The gaseous mixture passes out through an outlet 8.

The fuel oil is injected into the furnace through the tube 6 in the form of a filament, which falls to the bottom 9 of the furnace. The oil enters -Ia region of the furnace at which there is a very high temperature of 110)o C. or more According-ly, it undergoes an extremely sudden heating, which results in vaporization of the lower-boiling constituents attended by the cleposition of solid carbon, and then in a cracking of a considerable portion of the hydrocarbons, which is also accompanied by the deposition of further amounts of solid carbon in a finely' divided state. Preferably, the conversion of the fuel oil into a gaseous fuel should be completed during the passage of the filament of liquid fuel between the outlet of the feed tube 6 and the bottom 9 of the furnace. This requirement is fulfilled by the arrangement as described, as the fuel oil is introduced in the form of a nue jet 'or filament which presents a sufficiently large area to the action of the heat in proportion to the rate of now. If desired of course, the oil may be introduced into the furnace through a plurality of feed tubes, so that the complete flow is divided into separate filaments of small section. Y

The high temperature prevailing in the fuel oil inlet chamber is obtained by combustion of the earb'on to form carbon monoxide. It is necessary for the entire amount of carbon to be oxidized at this stage, with the exception of the small ahiount of carbon dioxide correspondingto the ehen'iioal balance, and that the oxygen should not combine with the hydrogen, at least in any appreciable amount. To satisfy these requirements air is injected in an amount correspond-Y ing to the desired reaction. Moreover, owing to the air being preheated to approximately 350, and despite the wholly incomplete nature of the oo'xnbiistion, a temperature is reached which cre-- ates working conditions leading to a satisfactory balance between the carbon monoxide and the carbon dioxide formed. In the event that some of the oxygen reacts with hydrogen, `the water vapour generated would in turn react with the carbon to forni water gas.

In addition to the supply of air through the annular space surrounding the oil feed tube or tubes, air may be supplied by means of the nozzles 5, whereby the air is divided and discharged obliquely for the purpose of creating turbulence in that region of the furnace where carbon deposits would otherwise tend to form in consequence of the incomplete oxidation 'of the fuel oil, i. e., at the ends of the paths of the liquid lamht or filaments through the furnace. The air supplied in this manner whirls around the fuel oil filament and deects the oil vapours to wards the high-temperature reaction' zone.

The oonbustible gaseous mixture leaves the furnace through the outlet 8 and is fed to a burner of conventional kind. Y

In the second forin of embodiment referred to there is employed a baffle furnace which is similar to the onelllu'strated in Figs. 2 and 3. The air is preheated by passing it through a jacket whichis in contact with fins adapted to cool the baffle furnace, down with the liquid fuel dickies in the form of a sim. A Y

'The fuel oil or similar higher-boiling liquid fuel is" supplied through a pipe II provided with a oontrol valve I2, arid flows into troughs I3 4 provided with a Weir, over which it trickles down the surfaces I4 which are provided with horizontal baiiles I5. The surfaces Ill -are slightly oblique, so that as the liquid nears the vbottom and becomes more viscous it trickles over increasingly shorter baffles.

The .air introduced through the pipe I6 sweeps over the vertical outer webs I'I 4and is heated thereby after which it enters the producer at the bottom thereof through a slit I8, from which point it rises to sweep over the baies I5. The gases passout by way of the outlet I9 and can then be fed to a burner of any known kind.

In the form of embodiment illustrated in Fig. 4 there is employed a hollow vertical cylinder having a top pipe junction 22 through which the gases are discharged, and a lower socket 23 for connection with an auxiliary burner 24 of conventional design, by means of which the gasification can be initiated rapidly and the temperature required therefor can be maintained contingently thereon by virtue-of not gases received from said burner. The liquid fuel to be gasified, for example fuel oil, is injected through nozzle 21, or is allowed to fall in the form of a thin filament, coaxially with the body 2I of the furnace. The air necessary to gasify the oil or the coke which accumulates at 25 on the bottom of the cylinder 2I is injected through nozzles 2e. The latter' are directed towards the deposit of coke 2,5 in such a way that gasification of the coke is obtained.

For the purpose of achieving a richer gas the air injected into the furnace to gasify the coke Y may be replaced partly or wholly by pure oxygen, whereby not only nitrogen in the air is eliminated, but at the same time the balance between carbon monoxide and carbon dioxide is displaced in a favourable direction owing to local elevation of the temperature.

lf desired, of course, the furnaces employed in carrying the invention into effect may be modified in various ways to suit particular requirements, particularly as regards their geometrical form, within the scope of the invention.

What we claim is: e

l. Apparatus for producing a combustible gaseous mixture from heavy liquid fuels comprising' a furnace, a fuel introductionpipe entering the top of said furnace, a plurality /of horizontal baffles on opposing interior walls of said furnace, the baiiies on one said wall being staggered with relation to the baffles on the other of said walls and forming a tortuous path through said fur-- nac'e, a plurality of vertical exterior webs on said furnace, a closed vessel'enclosing the bottoni por= tion of said furnace and that portion having said external webs, said furnace having a slit in the bottom thereof intercommunicating said furnace and said closed vessel, a gas inlet at the top ofV said vessel, and a gas outlet at the top of said furnace.

2. `Apparatus as claimed inuclaim 1, and wherein said opposing interior walls are oblique with respect to oneanoth'er and the distancerthere`u between diminishes toward the slit in said furnace, said baffles being increasingly 'shorter to# ward the bottom of said furnace.

ALBERT Ls Coii'N'T., HENRI GUILLON. REN ROUBINET.

(References 'a' renewingpage) REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Number Name Date Dalen Mar. 15, 1938 Dalen et a1. Aug. 20, 1940 Astradsson Oct. 1, 1940 Dalen et a1 Sept. 28, 1941 FOREIGN PATENTS Country Date France May 26, 1924

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