US3261762A - Fuel rectification apparatus - Google Patents

Description

July 19, 1966 KNAPP 3,261,762

FUEL RECTIFICATION APPARATUS Filed Aug. 6, 1962 FIGJ I/Vl/E'NTOR EDWARD M KNFIPF RTTDR AIEYS United States Patent 3,261,762 FUEL RECTIFICATlON APPARATUS Edward M. Knapp, 951 Livingston St., Arlington 5, Va. Filed Aug. 6, 1962, Ser. No. 214,876 1 Claim. (Cl. 196-115) The present invention is concerned with the conversion of one type of fuel into a dilferent type of fuel, the process being designed to permit the successful use of a previously unusuable fuel in a particular type of engine. From the above statement it will be obvious that the invention is concerned with a definable technical problem, which is:

In the gas turbine engine, fuel is combusted in such a way that the expanding products of combustion are impelled against the blades of a wheel and by their velocity and thrust cause the wheel to rotate rapidly, thus providing power through the kinetics of rotation. The makers of gas turbines have endeavored to use residual fuel oil in turbines, but the corrosive properties of such oils have in the prior art defeated all such use. Residual fuel oil by definition is a residue provided by the distillation of crude oils, and is a heavy viscous product. This of itself would provide no trouble, but virtually all of the residual fuel oils available contain vanadium, in a porphyrin structure derived from the reputed origin of petroleum in marine deposits. The vanadium is carried as the sequestered atom in the polynuclear structure. The normal vanadium content is on the order of 100 p.p.m. in crude oil, which is concentrated by the processes of distillation to 250 ppm. in residual oil. Thus, under combustion conditions where an excess of oxygen is present, the vanadium, pursuant to the chemical structure in which it is present burns to the very corrosive vanadium pentoxide, which in cont-act with reducing materials as in the metals of the turbine engine blades burns the turbine wheels away at an unacceptable rate. The problem is therefore-how does one modify resid' ual fuel oil in such a way that the vanadium is removed prior to combustion, so that the resulting fuel when used in the combustor will not provide corrosion.

The object of the invention therefore is to provide a means of changing the character of residual fuel oil, the change in character to remove the vanadium prior to combustion.

The object more specifically stated is to provide a device which can be attached to a gas turbine engine and decompose the fuel oil prior to the introduction of fuel to the oombustor in such a way that the vanadium is precipitated out of the fuel.

The invention is thus a thermal cracking device in which the heat of the exhaust of the gas turbine engine will produce a temperature in the oil greater than that required to decompose the oil and break the chemical bond which carries the vanadium at which time the vanadium combines with carbon from the oil and is removed from the fuel as vanadium carbide while the fuel becomes gaseous in state, and free of its metallic component takes on a substantially hydrocarbon characteristic which on combustion produces a non-corrosive carbon dioxide.

Having thus summarized the invention, I further define it by means of the drawings presented as follows:

FIGURE 1 is a cross section view of the device, shown on the long axis, with the longer cone positioned at the end of the exhaust housing of the turbine engine, and the shorter cone in opposition. FIGURE 2, is a cross section on a lateral axis, taken on line 2-2 of FIG- URE 1. FIGURE 3 is similarly taken on line 33 of FIGURE 1. FIGURE 4 concludes the presentation by a cross section taken on line 44 of FIGURE 1. The outer shell of the longer cone is 1, exposed directly to the heat and high temperature of the turbine exhaust. An inner shell 2 defines the vortex traced by the gas. A center tube 3 forms a path for the gaseous fuel created by the device to leave the device enroute to the conibustion chamber. Tube 3 is shown long, and in accordance with prior art in the development of vortex separators could be shortened in practice. Inner shell 2 is closed at the junction of the longer and shorter cones by separation wall 4, modified by shield 5 which serves the purpose of aiding the formation of the vortex. Injection tube for the entrance of liquid residual oil 6 is positioned in accordance with the prior art on vortex separators. Separated vanadium carbide in particles collect in the shorter and removable cone 7. The device is suspended in the exhaust stream by struts 8 and 9, which are repeated in any cross section view taken on a rotation of degrees from the one shown, and which in cross sections rotated to other degrees would be shown foreshortened. In the view shown the strut ends, head on, are omitted since their depiction would complicate the presentation. Finial 10 of the longer cone is shown as coming to a conical point, but could be any aerodynamically eificient shape in order to reduce turbulence in the exhaust stream and refrain from penalizing the turbine design. Finial ll of the shorter and following cone requires the same comment. The connection between the cracking cone exposed to the heat, and the collecting zone is through open ring 12, separating cones 1 and 2. For understanding in presentation it may be noted that in fabrication, cone 2, tube 3, separating plate 4, and shield 5 are fabricated in one piece, and are mutually self-supporting. Cone 7 in installation is removably attached to cone 1, thus permitting removal at stated times. Struts 8 and 9 are attached to the exhaust section of the gas turbine 13 by extension struts 14, which are fastened by insertion through the exhaust section wall.

Cone 2 may be described as foram-inous in that it is a network of passageways through which the particles of vanadium and vanadium carbide formed by the cracking operation pass. The vortex is formed by this inner cone and the gas in large part is confined thereby, but the centrifugal forces created by the vortex tend to drive the solid particles through the for-aminous cone screen so that they are separated and collected first on the inner surface of cone 1 and later in cone 7, passing through open ring 12.

In describing the inner cone the word foraminous has been used to denote an open or porous structure. No better term appears to be available in common parlance, but it is not properly descriptive. The structure is actually that of an open grillwork in which the open spaces occupy most of the lateral area and the metal grillwork occupies a very small portion of the area of the conical surface.

FIGURES 2, 3, and 4 are each cross sections, in which only the conical shells are shown. In FIGURE 2, surface 2 is shaded separately from surface 1. In FIG- URE 3, tube 3 occupies the center, and the conical surfaces 1 and 2 appear at the edge of the cross section. In FIGURE 4, conical surface 7 is shaded.

In operation, the device is attached to the discharge end of the exhaust of a gas turbine. Residual fuel oil is introduced into the chamber heated to the temperature of the exhaust gases, and the stream impinges upon shield 5 and the chemical compounds therein are decomposed by the heat present, represented by the temperature. The gas product of the decomposition describes a helical spiral and exits through the center tube 3. The particles of solid vanadium or vanadium carbide, having a greater inertia derived from relative mass, tend to move in straight lines passing through cone 2, and into the space between cones 1 and 2, from which they are removed to the detachable cone 7 for periodic collection.

It will be obvious to those skilled in the art that the stoichiometry of decomposing a chemical compound in which the number of carbon atoms is roughly equal to those 'of hydrogen provides for the deposition of uncombined carbon, whose valences for hydrogen are unsatisfied. To remedy this situation a controlled amount of water is added to the residual oil to provide a controlled amount of hydrogen and oxygen to satisfy these valences, not through complete combustion as in the combustor of the engine, but through reduction through use of the hydrogen and incomplete combustion as in the formation of carbon monoxide, a compound which is an efficient fuel. It will be obvious that by the addition of water, which disassociates under the temperature conditions in the presence of carbon, I am using reducing conditions to rectify the fuel rather than permitting complete combustion with formation of vanadium pentoxide.

The device has been described entirely in terms of its use to remove vanadium from residual fuel oils in order to permit the use of those fuel oils in gas turbine engines. In so doing it will also reduce to the gaseous rather than the vapor state the other chemical compounds of carbon and hydrogen present in the oil, and will also crack such compounds under reducing conditions to simpler hydrocarbons, and to carbon monoxide. In this connection the stoichiornetry indicates that the additional water required in order to fully satisfy the chemical bonds of the excess carbon for that portion of the residual fuel oil containing vanadium is approximately 16 times the amount of such chemical compounds. No calculation has been made for the addition of water to satisfy the chemical bonds of additional carbon atoms present in the unoombined state.

Having thus described my invention, I claim:

An apparatus including an exhaust gas flared opening of a gas turbine for discharge of hot exhaust gases and having a heater inserted in said flaring opening, said heater consisting of three cones fabricated from metallic sheet, the said. heater being fitted with an inlet pipe for the introduction of liquid fuel oil containing vanadium and having an outlet pipe for the egress of fuel gases, said fuel gases being derived from. said liquid fuel oil by decomposition and thermal cracking thereof in the apparatus, said liquid fuel being mixed with a stoichiometrically determined amount of water prior to introduction into said heater, the first of said three cones of the heater being fabricated with a sol-id surface and fitted with radially extending struts to position the apex of the first cone forwardly in said flared exhaust opening of the gas turbine, the second of the three cones being foraminous as to its conical surface and having attached to it a solid circular base, a solid arcuate shield having a concave surface disposed at one corner of the base of said second cone to provide a vortex in the fluid flow and an angular outlet conduit, one end of which extends vertically along the vertical axis of said second cone and having an opening at the apex of the second cone, the other end of said conduit extending along in the plane of said base for discharging said fuel gases, the said second cone being disposed inside and in parallel relationship with and spaced from said first cone to provide an opening at the base of the first and second cone, a third cone of shorter extent than said first cone and 'removably attached to the first cone so that their bases coincide whereby liquid fuel is introduced into said inlet pipe within the second cone for vaporization and thermal cracking of the fuel and withdrawn as a vapor in said outlet conduit and the vanadium deposits as particles which penetrate the foraminous second cone and pass through the opening therein and into said third cone.

References Cited by the Examiner UNITED STATES PATENTS 655,757 8/1900 Chambost.

938,506 11/1909 Fr-ickey -459 940,827 11/1909 Sheward 55459 1,576,787 3/ 192 6 Reichh'elm. 2,470,634 5/1949 Morgan et al. 196l04 X 2,477,935 8/1949 Miller 55459 2,790,554 4/1957 Work 55-459 NORMAN YUDKOFF, Primary Examiner.

F. E. DRUMMOND, H. M. SILVERSTEI-N,

Assistant Examiners.

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