US2813784A - Method for the gasification of heavy fuel oils - Google Patents

Description

Nov. 19, 1957 H. GUILLO'N 2,813,784

METHOD FOR THE GASIFICATION HEAVY FUEL OILS Filed se t. 1, 1954 2 Sheets-Sheet 1 I N\'/ENTOR HENRI GUILLON Atbor l =2 Nov. 19, 1957 H. GUILLON 2,813,784

METHOD FOR THE GASIFICATION OF HEAVY FUEL OILS Filed Sept. 1, 1954 2 Sheets-Sheet 2 6: Fig.3. 7

HENRI GUILLON' At t brw :33

m VENTOR 1 United States Patent METHOD FOR THE GASIFICATION OF HEAVY FUEL OILS Henri Guillon, Paris, France, assignor to Oflice Central A Ever since heavy fuel oils began to be used, attempts were made for gasifying them and the simplest method used consisted in a vaporization by calefaction; this process could not remain in use, except with light 0118 those of the gas oil type, the vaporization of which leaves areadue in the shape of coke, which is almost negligible. On the contrary, for heavier oils, the process has been abandoned due to an abundant formation of coke which paralyzes operation.

According to a process described in the U. S. Patent No. 2,580,179, the fuel oil is gasified by injecting it into an oven at 1100 C. in the shape of thin jets falling on the bed plate, which has the effect of causing a vaporizing of the volatile elements and a deposit of solid carbon, then a cracking of the hydro-carbons, with a new separation of carbon in a finely divided condition, after which the gases thus formed pass through a second apparatus where they are burnt in a known manner. In the same U. S. patent, apparatus is described for the putting in application of this process.

The object of the present invention is a process for the gasification of heavy fuel oils, the process being characterized in that the gasification of heavy oils is obtained by a controlled oxidation at a temperature of about 1400" C., i. e. between 1300 C. and 1500 C., which has the eifect of giving hot combustible gases containing an important proportion of carbon oxide and hydrogen.

Another object of the invention is a device for the putting in application of the process, said device being characterized by the presence, in a round oven, of eddying air jets, which sweep the oil layer spread over the sole, while preventing a projection of oil on the walls.

There are described hereinafter, by way of example and not of limitation, and following the description of the process, two preferred forms of embodiment of devices designed for the putting in application of said proc ess. This description refers to the appended drawing wherein:

Figure l is a diagrammatic view, in vertical section, of the first device.

Figure 2 is a diagrammatic view, in transverse section.

Figure 3 is a diagrammatic view in vertical section of the second device.

Figure 4 is a diagrammatic view in transverse section.

According to the present invention, the gasification of the heaver oils (for the French classification, fuel oils Nos. 1 and 2, coal tars) is effected by a controlled oxidation obtained by the following process: Heat is evolved by the oxidation, so that once the reaction has been started, the oil introduced in the gasifier is first subjected to a violent heating which vaporizes it, releasing on the one hand vapours of hydrocarbons, and leaving, on the other hand, residual coke; the vapours are rapidly separated into light elements then into hydrogen and powdery carbon. The mode of penetration of the air in the reaction oven described hereinafter has the effect of subjecting to oxidation both the coke (as it is being formed) and the volatile elements. In the presence of oxygen from the air suitably dosed with respect to the oil, the carbon and oxygen are partly oxidized for giving a gas mixture containing CO2, CO, H2, H20 and, in the medium where a temperature of about 1400 C. is obtained, the proportions of CO and H2, combustible gases, are definitely predominant at the same time owing to the action of the masses in presence and to that of temperature which rapidly displaces the equilibrium of the elements in the direction indicated. Practically, by adjusting the respective dosings of air and oil, a gas may be obtained containing exclusively CO2COH2-H2O, or containing also a small amount of light hydrocarbons (CH4) and carbon in suspension: this possibility of adjustment is expressly used for producing industrial combustible gases capable of giving a flame with a radiating power more or less high. The process is further characterized by the production of a hot combustible gas, the final temperature of which is little less than thatch-1 taining in the zone of reaction itself.

By way of example, Figure 1, attached, represents in vertical section a gasification apparatus designed for putting the process in application: a cylindrical metal tank 1 contains an inner refractory lining 2 and a heat insulating element interposed between the metal and the refractory; the sole comprises a central projection 4; the gases escape through the orifice 5; the oil distributed by a known device enters through tuyeres 6 the inside of the apparatus and flows on the annular sole 7; the air is injected through a tuyere 8 connected with a circular distribution coriduit 9. It is advantageous that the oil tuyere 6 be inside an air tuyere 8 for preventing the oil from flowing prematurely on the vertical wall.

Figure 2 shows a diagrammatic horizontal section of the apparatus showing, in particular, the tangential arrangement of the air tuyeres 8; three oil injecting tuyeres are represented, distributed regularly around the axis of the apparatus.

For one of the oil tuyeres 6, there is shown diagrammatically a group of three air tuyeres 8 connected with a portion of the circular distributing conduit 9 and so oriented that their respective impact zones on the sole 7 enclose the oil jet and that the respective trajectories of air jets shown in dotted lines be tangent, on the sole 7, to circles 10 shown in broken lines.

The inner wall 2 of the heat insulated enclosure 1, 2, 3 is built so as to withstand the action of very hot gases moving at a high velocity. The heat insulated enclosure is cylindrical and vertical but, within the scope of the invention, it might just as well be oriented differently for lending itself to an easy use of the heating apparatus provided. The tuyeres 6 through which the oil is injected are distributed regularly over the periphery; the injection might also be axial, particularly if the cylinder were placed horizontally as will be seen later in another form of embodiment. The tuyeres 8 injecting the air intended for the controlled oxidation of the oil are so oriented as, on the one hand, to sweep the oil which is spread over the sole 7 and, on the other hand, so as to surround this oil jet for avoiding projections on the vertical walls where accumulations and agglomerations of coke would take place; thus the formation of coke is constantly localized on the sole 7 and the coke is oxidized as it is formed; In addition, the air tuyeres 8 are oriented tangentially to the inner circles 10 the centres of which are on the axis of the cylinder so as to impart to the gaseous mass in reaction a violent eddying motion, for ensuring an intimate mixing of the elements to be reacted, and for lengthening the paths of the particles and consequently improving the condi' tions of contact. To this effect, the air is injected under a pressure of the order of 0.5 to 1 meter of water above that which obtains in the enclosure of the gasifier. It is normally intended that the process according to the present invention does not use higher pressures so asto require only the use of ventilators and not of compressors, in the most frequent cases of industrial utilization in which the pressure of utilization of the gas is only a few centimeters of water at a maximum. For particular uses, however, the gasifier according to the present invention may operate at pressures much above the atmospheric pressure which, for example, may reach about 30 kg. per square centimeter.

In order to avoid that the fuel oil spread over the sole outside the trajectory of the air jets, it is advantageous that the latter-comprise the central circular plate 4 slightly protruding and the more hollow annular space 7 between the :plate 4-and the vertical wall from Whic'hthe oil flows.

For ensuring permanently an oil flow proportional to that of the air inaccordance with the adjustment; provided, the two flows are automatically associated by devices known per-se.

For starting-the operation, the 'gasifier is first raised to the steady state temperature by any auxiliary source of heat.

In another form of embodiment, the-axis of the cylinder is arranged-horizontally (see Figures 3 and 4). A metal tank 11 similar to that of Figures 1 and 2 containsthe refractory lining 12 and the heat insulating lining 13. The oil to be gasified is injected through theaxial tube 14, surrounded by an air tuyere 15. The air for gasificationis injected for the greater part through the tuyeres 1 6 arranged tangentially and extending from one or two circular conduits 17. As in the embodiment described with refer,- ence to Figures 1 and 2, the oil flows on a horizontal portion of the wall of the tank where it is gasified under the action of the tangential air jets.

It is generally advantageous, in applying the process according to the invention, to injectair previously warmed up by a known means, the warm air acting in a favorable direction on the composition of the gas obtained (a higher content in combustible gases), not so much because of the calories involved as because of its action on the speed of the equilibrium reactions.

Of course, Without departing from the scope of the present invention, nonessential details could be changed in the above described devices, given simply by way of examples.

What I claim is:

A process for the gasification of very heavy liquid fuels having a Conradson'i'ndex of about 4% to 12%, which consists in injecting the oil in the form of a constant and undivided jet, without any previous atomization, onto the hearth of the furnace, vaporizing said oil at a high temperature localized on the hearth, and gasifying the Conradso coke produced in large quantities as it is formed by means of air jets distributed through nozzles extending through the refractory wall of the furnace and adapted to project onto said hearth jets of combustion-supporting air, other nozzles extending coaxially within said air nozzles and being adapted to project the heavy oil onto the hearth in theltlorm of a continuous jet, the cohesion of this jet being protected until said jet actually meets the hearth surface against the combustion eddies in the furnace by the tubular air sheath projected by said first nozzles.

References Cited in the file of this patent

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