GB1564081A

GB1564081A - Liquid fuel burning apparatus and process for burning liquid fuel

Info

Publication number: GB1564081A
Application number: GB274977A
Authority: GB
Original assignee: Columbia Chase Corp
Current assignee: Columbia Chase Corp
Priority date: 1976-10-26
Filing date: 1977-01-24
Publication date: 1980-04-02
Also published as: CH612744A5; DE2706037A1; BE851393A; CA1082586A; AR216460A1; FR2369503B1; MX5179E; NL7701524A; ES455893A1; JPS5384233A; DE2706037C2; JPS6046323B2; BR7701012A; IT1073258B; SE433775B; FR2369503A1; SE7701078L

Description

(54) LIQUID FUEL BURNING APPARATUS, AND PROCESS FOR BURNING LIQUID FUEL (71) We, COLUMBIA CHASE COR PORATION, whose principal place of business is 220 Forbes Road, Braintree, Massachusetts, United States of America do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The use of water, in various quantities and forms, as an additive to provide improved combustion of hydrocarbon fuels and waste gases is old.

Such processes have been proposed for various purposes: e.g. avoiding unsightly smoke from refinery waste-gas flares and improving the economics of home-type oil burner systems. These processes have included adding the water to the combustible as liquid, or as vapor, and in a very broad range of percentages.

Among the U. S. patents illustrative of such processes are those which utilize very high levels of water (U. S. Patent 3,104,311) and very low levels of water (U. S. Patent 3,862,819). Some patents disclose mixing of the water with the oil (Patent 3,706,942) and some use the water in the form of a vapor catalyst - often injecting the water as vapor.

While some of the processes suggested in the art are probably of little value becuase they use too little or too much water, it may be safely assumed that, when operating at equilibrium, a substantial advantage in some combustion characteristics is achieved with many of the processes described in the art.

Nevertheless, substantial problems remain in implementing such processes commercially. The high combustion efficiencies to be realized are accompanied by the use of less secondary air. This means that more water of combustion is in a given volume of stack gas and undesirably high dew points are experienced. Simultaneously, the efficient high-temperature process in the furnace results in a highly efficient heat transfer in a properly designed furnace. This further decreases the amount of waste heat and also tends to increase the probability that a stack gas temperature will fall below its dew point.

Even when the dew point is generally maintained at a minimum practical level, any temporary fluctuation in draft conditions can cause serious condensation problems in the heat transfer and stack-gas handling portions of a heating system. What is required is a dependable, stable means to operate a water-catalyzed combustion process at something approaching a steady state. Problems relating to flame stability, to re-ignition, and even to the usual changes in draft air or in heating loads within a furnace, must be minimized. All this is ideally achieved without sacrificing any of the substantial combustion efficiency, which is attainable with H2O-promoted combustion.

According to a first aspect of the present invention there is provided a process for burning liquid fuel in a combustion zone, said process comprising the steps of: (i) emulsifying said fuel with water and a dispersing gas; (ii) passing said emulsified fluid under a higher pressure to a burner head and into said zone at a lower pressure, causing said gas to expand and disperse said hydrocarbon; and (iii) simultaneously providing a watervapor-bearing atmosphere with which said emulsified fuel is dispersed by the expanding gas and burnt.

According to a second aspect, the invention provides burner apparatus comprising an emulsification chamber having inputs for receiving liquid fuel and water, and for receiving under pressure a dispersing gas, the chamber and output conduit means therefrom being arranged such that a mix ture of an emulsion of fuel and water and of the dispersing gas including water vapor is fed under pressure to a combustion chamber, and that the gas under pressure expands into the combustion chamber, and comprising means whereby the consequently dispersed fuel is burnt.

Embodiments of the invention provide an H2O-promoted combustion process of hydrocarbon liquid which provides a flame of improved stability and efficiency.

Embodiments of the invention can be adapted for large industrial heating plants and in power generating plants as well as in smaller residential units.

An object of the invention is to provide a means for achieving a more stable and more efficient combustion process.

An embodiment of the invention utilizes a mixture of water and fuel oil for emulsification in the presence of a gaseous dispersing fluid such as air or steam; the emulsion may be fed into the mass of the fuel to be burned, or itself may form the mass.

One embodiment is a process wherein In embodiments liquid hydrocarbon fuel to be burned is emulsified with water in the presence of gas which will expand rapidly when the fuel is discharged through a nozzle (i.e. burner head) into a furnace; usually a substantial amount of water. 5% to 15% by weight based on fuel, is vigorously agitated with the expansion gas and the fuel to be burned. This is believed to aid the emulsification of the fuel with the waer and the expansion fluid together.

(2) A substantial amount, typically 5% to 20% by weight, of H2O is contained in a vapor atmosphere into which the emulsified hydrocarbon is expanded and burned. This vapor-bearing atmosphere may be provided around the burner head or, provided through the burner head, or provided by mixing air from a source proximate to the burner head with H2O which is contained in the dispensing fluid injected through the burner head. The H2O can include both steam and water used in the emulsification step.

This combination of extraordinary disper sal of atomization of the hydrocarbon vapor at the burner head and vaporized water provides an extremely efficient, stable flame.

Thus the dispersing fluid is a gas. As it passes through the nozzle (i.e. burner head) from a higher pressure into the combustion zone at a lower pressure, the gas expands and disperses the liquid hydrocarbon fuel.

Passage through the nozzle of the burner is usually sufficient means to allow the mixture initially under pressure to be reduced in pressure and thereby to expand in the combustion chamber.

Of particular importance, we find in embodiments, is the ability to achieve this flame with little, if any, excess oxygen.

Consequently, it is believed that any excessive formation of S03 can be substantially avoided. Also, as those skilled in the art will realize from reading this disclosure, such a highly efficient combustion will minimize the amount of nitrogen which must be heated, will allow highly efficient heat exchange, primarily through radiation, and allow greatly reduced stack temperatures and, most importantly, provide a process which allows more stability and consequently a more dependable ratio of the selected stack gas temperature.

The process exhibits such extraordinary efficiency and stability, it is throught, because the gaseous material, e.g. air or steam is more efficiently emulsified when using the vigorous gas/water/hydrocarbon contact step and that this results in an intimately mixed feed which, upon exiting the burner head, disperses with such rapidity to such small droplets that the rate of combustion of the fuel mass being fed to the furnace is achieved with an unusual combination of rapidity and efficiency. The presence of water vapor in the zone into which this rapid combustion takes place is believed to provide a stabilizing "brake" on the combustion rate, thereby providing a highly efficient and practical process. It is usually convenient to utilize excess gas from the conditioning tank as an atomizing fluid at the burner head.Normally such excess gas, be it air or steam or the like, will have picked up some fuel in the conditioning tank.

It has been observed that the flame produced by the most efficient use of the process is a vivid greenish color; this color seems to characterize the quality of the more efficient processes operated according to the invention. However, it should be realized advantage is also achieved at temperatures below those at which the green flame is noticed.

Finely divided and fluidized coal can also be added to liquid fuel and pumped to an appropriate burner head, as an emulsion under pressure and in the presence of the pressurized gas, and the emulsion dispersed into a water-vapor bearing shroud. It is contemplated that the dispersing gas is advantageously a different gas from any used as the primary fluidizing medium. For example, if the primary fluidizing agent is air, the dispersing gas may be steam or a lighter gaseous hydrocarbon. In any event, the important aspect of this coal-bearing emulsion combustion process is as before, and according to the invention to utilize the expansion of gas at the burner head, as it emerges from the nozzle, to disperse the fuel including the coal dust into a highly humidified atmosphere.

It is desirable to preheat the heavier liquid hydrocarbon fuels. In general, it is not necessary to preheat No. 2 oil, and other such less viscous oils, under most temperature conditions. The preheating can be achieved by mixing with a heated fluid, such as steam used as a dispersing gas, or by any other heating means known to the art.

It is also advantageous, in some situations, to utilize the process of the invention in a mode wherein some hydrocarbon fuel is carried into the zone around the burner head in the water vapor bearing air. Normally, the amount of such fuel will be less than will allow the air to support combustion by itself. Nevertheless, the smaller quantities of hydrocarbon seem to enhance the quality and stability of the combustion.

In conJunction with the accompanying drawings there are shown and described a preferred embodiment of the invention and suggested various alternatives and modifications thereof, by way of example.

In the accompanying drawings Figure 1 is a diagrammatic view of one fuel conditioning apparatus emobodying the invention; Figure 2 is a side elevational view of a residence type oil burner system with the apparatus of the invention incorporated therein, parts being broken away and in half section, for clarity.

Figure 3 is an enlarged fragmentary side elevation view of the firing unit for use with the burner embodying the invention of Figures 1 and 2; Figure 4 is a plan view; Figure 5 is an enlarged side elevation in half section of the vapor burner tip shown in Figure 3; Figure 6 is a schematic diagram showing the use of steam as an emulsifying fluid in a process according to the invention; and Figure 7 shows a front view of the burner tip of Figure 6.

As shown in Figures 1 and 2, the apparatus and method of the invention is incorporated into a typical home heating system 30 of the type having an oil tank 31, usually capable of holding about 200 gallons of liquid oil 32, there being an air vent 33 and a filler pipe 34. A fuel line 35 normally extends to a conventional oil burner 36 having a motorized fuel pump 37, a gun, or barrel, 38, and a burner tip 39. Tip 39 emits atomized fuel 41 to form a flame of generally conical configuration, 42, into the combustion chamber 43 of the hot air, hot water, steam or other type heating unit 44, upon call of thermostats, all in a well known manner.

In this invention, a pressure tank 45 is interposed in liquid fuel line 35 by means of valves 46 and 47, so that the portion 48 therebetween may be used, if conventional heat is desired, but portion 48 is bypassed when the supplementary heat of the invention is desired. The line portion 48 is shown in dotted lines for clarity in Figure 2. A pressure gauge 49 indicates the pressure within tank 45, the pressure being relatively low and about 5 psi. The tank 45 includes a top closure 51 sealed around the peripheral flanges 52, by suitable screw threaded clamps 53 to the botton, or base, 54.

Tank 45 indues a liquid fuel inlet 55, connected by conduit 56 to valve 46, for receiving oil from tank 31 and a liquid fuel outlet 57 connected by conduit 58 to valve 47 for delivering oil from tank 45 to the burner 36. Tank 45 also includes a water inlet 59 in the lower portion 61 of the tank and a vapor, or fume, outlet 62 in the upper portion, or vapor chamber, 63 of the tank.

An air, or vapor, inlet line 64 leads from a motorized air pump 65 for feeding pressurized air into the tank 45 to create the desired vapor pressure and turbulence therein. This air is emulsified with the oil, and water described below, and will act as the dispersing gas therein, when it expands from the emulsion in the combustion chamber 43.

Water supply means 66 is provided, including the water pipe 67 connected to a source of water under pressure such as the house main 68 and having a normally closed solenoid valve 69 which is opened to admit water into the lower portion 61 of tank 45 when a signal is received from suitable level sensing means such as an electrode 71 in a circuit, not shown, including the coil of valve 69 and a source of 110-volt current. A float valve, photo cell or any other suitable means may be used to maintain a predetermined level of water in tank 45 to form a layer of water of predetermined thickness, or height therein, all in a known manner.

The liquid fuel supply means 75 of the invention includes the oil tank 31, fuel lines 35 and 56, valves 46 and 47, liquid inlet port 55, tank 45, liquid outlet port 57, fuel line 58, liquid fuel pump 37 and the burner tip 39.

Automatic liquid fuel control means 76 is provided in the form of a valve 77 opened and closed by a float 78 riding on the layer of oil 79 in the intermediate portion 81 of tank 45, the layer 79 of oil floating on the layer 82 of water in the lower portion 61 of tank 45.

The vaporized fuel formation means 83 includes a bypass, or recirculation, liquid fuel line 84, leading from the joint 85 in fuel line 58, in the rear of the fuel pump 37 and in advance of the burner tip 39, to conduct liquid oil under pump pressure through a pre-heating coil, or jacket, 86, and thence to an outlet 87, preferably in the form of a perforated bubbler tube, in the lower portion 61 of tank 54 below the predetermined level of the water layer 82. The heating coil 86 preferably encircles the gun, or barrel, 38 of burner 36 and extends beyond the end 88 thereof so that some of the convolutions are in the path of the truncated conical flame 42 in the combustion chamber 43. Thus each time the thermostatic, or other, controls of oil burner 36 close the circuit to energise pump 37, liquid fuel under pressure is delivered to burner tip 39 for atomization, ignition and flame.Simultaneously, a portion of the pressurized liquid fuel is heated in coil 86 and delivered to the outlet 87 to produce heated bubbles 89 of oil which rise upwardly through the water layer 82 and upwardly through the liquid oil layer 79 to form enriched vapor, or fumes 91 in the upper portion, or vapor chamber, 63, of the pressure tank 45. Such fumes 91 preferably contain between 3% and 13% of water vapor or steam.

The enriched vapor supply means 92 of the burner includes the vapor outlet 62 of tank 45 and the vapor conduit 93 leading to the vapor burner tip 94 which is located in combustion chamber 43 in the path of the flame 42, just in front of, and below the level of, the burner tip 39. Thus the vapor 91 is ignited by the flame 42 to supplement the heat produced by the burner tip and form a flame pattern 95 as shown diagrammatically in Figure 1.

Vapor pressure of about 5 psi is achieved in the upper portion 63 of tank 45 by the motorized air pump 65 which is in circuit with fuel pump 37 so as to be energised for each period that the fuel pump is energised by the heat controls. As shown air pump 65 may draw fumes through influent conduit 96 from the upper portion 97 of fuel tank 31, or may draw fresh ambient air from the atmosphere by means of two way valve 98.

Preferably, however, the tank vent 33 is sealed, so that pump 65 draws fresh air from inlet 101 shown in dotted lines in Figure 1, drives the air into a perforated tube bubbler 102 (Figure 2) and thereby creates enriched fumes 103 under pressure in the upper portion 97, which pressurized fumes are conducted through line 96 to form a fuel/ water/air emulsion at a relatively high pressure in the upper portion 63 of tank 45, and thence to the vapor burner tip 94 in the combustion chamber 43 which is at a lower pressure. There, the air content of the emulsion expands and disperses the fuel in an atmosphere containing water vapor, for burning of the fuel.

As shown in Figures 3, 4 and 5 the vapor burner tip 94 is preferably in the form of a screw-threaded nipple 104 having at least one orifice 105, and preferably three thereof as shown in Figure 4. The preferred location for tip 94 is shown in Figure 3.

The following example is carried out in a auxiliary furnace used by a large utility to generate steam for use in power generation.

The furnace, or "boiler" as it is commonly called, has 5520 feet of heating surface and is designed to produce about 40,000 to 80,000 Ibs of saturated steam per hour at 250 psig: It is equipped with 240 tubes (2-inch diameter and 0.150 wall thickness) in its furnace section and 448 similarly-sized tubes in its convection section.

The furnace is equipped with a firing head 204, and a fuel-conditioning unit 200 as shown schematically in Figure 6.

Fuel is No. 2 oil and it is supplied at a rate of 300 gallon per hour.

Steam at 100 psig, is supplied at a rate which is commensurate with the normal steam-atomization procedures known to the art.

Air is added to the burner in a swirling pattern about the periphery of the burner head in a quantity of about 1% greater than that required to achieve a 100% theoretical combustion of the fuel.

The following example illustrates the furnace being operated to produce about 40,000 Ibs of steam per hour.

Referring to Figure 6, it is seen that the fuel is piped into conditioning zone 209 of conditioning unit 200 through conduit 202 wherein it is preheated (and otherwise conditioned, as will be described below) before being sent to firing head, or nozzle, 204, through conduit 226.

Steam comes through conduit 206 into the outer conditioning zone 203 of conditioning unit 200 wherein it is mixed with some water and oil. The steam thus "conditioned" or enriched is then fed to nozzle 204 via nozzle conduits 210 to merge and mix with fuel in integrator section 212. Thence the mixture is passed through nozzle conduits 214 to atomize and disperse within combustion chamber 218, the conduits 214 being seen as to disposition also in the front view of the nozzle, of Figure 7.

It is noted that some oil is supplied to outer conditioning zone 203 of conditioning unit 200 via oil-supplement tube 220 wherein it is mixed with steam. Water is similarly supplied via water-supplement tube 222.

This mixing action of steam, water and oil impart a small, very well-dispersed quantity of oil into the steam, which is to act as the dispersing fluid. The amount of oil so added will be small, usually well below the 1% of total hydrocarbon fuel fed into the furnace and will not make the resulting dispersing fluid combustible, by itself; but, nevertheless, is believed to aid process combustion stability and the efficiency of combustion.

Water is added at a rate of about 5% to 8% by weight of fuel oil. This quantity of water is adequate to bring about a satisfactory emulsification of oil, steam and water for delivery to the burner head through the fuel conduit. Excess steam, carrying some hydrocarbon, is carried through the steam conduit for use as atomizing gas. About 60% to 80% of this water is added to the oil, via conduit 222A, to form an emulsion with the oil in inner vessel 209. The rest is added to the steam-jacket zone 203 via conduit 222. Similarly, steam is added, through conduit 220A, to the oil and water within inner vessel 20o help form the desired steam- and water-emulsified oil mixture to be fed through conduit 226 to burner head 204.

When the steam-emulsified hydrocarbon is passed from a higher pressure into the burner head and thence into furnace zone, or combustion chamber 218, the fluid expands rapidly to disperse the oil-bearing feed. Use of a H2O bearing dispersing gas helps provide an exceptionally compatible atmosphere into which the emulsified hydrocarbon can be instantly dispersed and burned. As indicated in the example above, a relatively small quantity of oil pre-existing in the H2O bearing dispersing gas seems to markedly improve combustion characteristics.

The resulting combustion reaches a temperature of about 3000"F. The efficiency of the combustion is about 96%. Temperatures of about 3200"F and combustion efficiencies approaching 100% can be achieved in many installations by further cutting back of the oxygen.

It should be realized that the above description is given for illustrative purposes only. Continued operation of the process at elevated temperatures should not be attempted unless the particular boiler or furnace is carefully evaluated for its ability to withstand the temperatures inherent in the process.

WHAT WE CLAIM IS: 1. A process for burning liquid fuel in a combustion zone, said process comprising the steps of: (i) emulsifying said fuel with water and a dispersing gas; (ii) passing said emulsified fluid under a higher pressure to a burner head and into said zone at a lower pressure, causing said gas to expand and disperse said hydrocaroon; and (iii) simultaneously providing a watervapor-bearing atmosphere with which said emulsified fuel is dispersed by the expanding gas and burnt.

2. A process as defined in Claim 1 wherein said dispersing gas is air.

3. A process as defined in Claim 1 or 2 wherein said water-vapor-bearing atmosphere comprises three to 13% of water vapor or steam.

4. A process as defined in Claim 1 wherein said dispersing fluid is steam.

5. A process as defined in any of Claim 1-4 wherein said water-vapor-bearing atmosphere comprises a quantity of hydrocarbon fuel which is insufficient to support combustion.

6. A process as defined in Claims 1, 4 or 5 wherein said emulsifying includes the previous step of intimately contacting some steam, water and a small portion of said fuel in a steam jacket zone, then mixing effluent from said steam jacket zone in a conditioning zone with fuel to cause the emulsifying, and supplying the resultant mix to said burner head.

7. A process as defined in Claim 6 wherein said process is operated with a quantity of water fed directly into said conditioning zone and indirectly therein from the steam jacket zone which quantity is equal to about 5% to 8% of hydrocarbon fuel burned in said process.

8. Burner apparatus comprising an emulsification chamber having inputs for receiving liquid fuel and water, and for receiving under pressure a dispersing gas, the chamber and output conduit means therefrom being arranged such that a mixture of an emulsion of fuel and water and of the dispersing gas including water vapor is fed under pressure to a combustion chamber, and that the gas under pressure expands into the combustion chamber, and comprising means whereby the consequently dispersed fuel is burnt.

9. Burner apparatus as defined in Claim 8 comprising: a sealed, pressurized, water tank as said emulsification chamber; said inputs being provided with; means for maintaining a layer of water in said tank at a predetermined level; means for supplying fuel oil into said tank, under said layer of water, to bubble up therethrough and form a layer of fuel oil, of predetermined depth, on said layer of water; means for pre-heating said fuel oil, to a predetermined temperature, prior to its introduction into said water tank, so that hot oil bubbles mix with said water and form enriched combustible vapor in the top of said pressurized water tank; air pump means for feeding pressurized air as said dispersing gas into said tank to create predetermined pressure therein; and said output conduit means including fuel line means for conducting said enriched vapor under said pressure from the top of said sealed water tank into said combustion zone for its expansion and burning.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Water is added at a rate of about 5% to 8% by weight of fuel oil. This quantity of water is adequate to bring about a satisfactory emulsification of oil, steam and water for delivery to the burner head through the fuel conduit. Excess steam, carrying some hydrocarbon, is carried through the steam conduit for use as atomizing gas. About 60% to 80% of this water is added to the oil, via conduit 222A, to form an emulsion with the oil in inner vessel 209. The rest is added to the steam-jacket zone 203 via conduit 222. Similarly, steam is added, through conduit 220A, to the oil and water within inner vessel 20o help form the desired steam- and water-emulsified oil mixture to be fed through conduit 226 to burner head 204. When the steam-emulsified hydrocarbon is passed from a higher pressure into the burner head and thence into furnace zone, or combustion chamber 218, the fluid expands rapidly to disperse the oil-bearing feed. Use of a H2O bearing dispersing gas helps provide an exceptionally compatible atmosphere into which the emulsified hydrocarbon can be instantly dispersed and burned. As indicated in the example above, a relatively small quantity of oil pre-existing in the H2O bearing dispersing gas seems to markedly improve combustion characteristics. The resulting combustion reaches a temperature of about 3000"F. The efficiency of the combustion is about 96%. Temperatures of about 3200"F and combustion efficiencies approaching 100% can be achieved in many installations by further cutting back of the oxygen. It should be realized that the above description is given for illustrative purposes only. Continued operation of the process at elevated temperatures should not be attempted unless the particular boiler or furnace is carefully evaluated for its ability to withstand the temperatures inherent in the process. WHAT WE CLAIM IS:

1. A process for burning liquid fuel in a combustion zone, said process comprising the steps of: (i) emulsifying said fuel with water and a dispersing gas; (ii) passing said emulsified fluid under a higher pressure to a burner head and into said zone at a lower pressure, causing said gas to expand and disperse said hydrocaroon; and (iii) simultaneously providing a watervapor-bearing atmosphere with which said emulsified fuel is dispersed by the expanding gas and burnt.

2. A process as defined in Claim 1 wherein said dispersing gas is air.

4. A process as defined in Claim 1 wherein said dispersing fluid is steam.

10. Apparatus as defined in Claim 9

wherein said air pump means includes a perforated nozzle within said tank, under the level of said water, for creating a large volume of air bubbling up through said water to mix with said enriched vapor.

11. Apparatus as defined in Claim 9 or 10 wherein said oil pre-heating means includes an oil supply line wth a coil having convolutions in said combustion chamber.

12. Apparatus as defined in Claim 11 including an atomized fuel burner nozzle within the combustion chamber; additional liquid fuel supply means connecting one of said inputs to a fuel tank to fill the intermediate portion of said sealed water tank with liquid fuel floating on said water; automatic liquid fuel control means for maintaining said liquid fuel on said water at a predetermined level; said mixture being fed to said nozzle; said oil pre-heating means comprising a liquid fuel line leading from the feed to said nozzle.

13. Apparatus as defined in Claim 12 comprising enriched vapor supply means including a vapor tip in said combustion chamber, a vapor conduit connecting said tip with a vapor outlet of said pressurized tank, and air pressure supply means for maintaining predetermined pressure in said pressurized tank.

14. Apparatus as defined in Claim 13 wherein said enriched vapor supply means includes a motorized pump mounted on the exterior of said pressurized tank.

15. Apparatus as defined in Claim 13 or 14 wherein said enriched vapor supply means includes an air pump having an air inlet in the top of the liquid fuel tank and having a perforated tube outlet in the bottom of said pressurized tank, closure seal means on said liquid fuel tank, and an air inlet conduit leading through the closure and through the upper portion of said liquid fuel tank to a perforated tube bubbler in the lower portion of the fuel tank, wherefrom air bubbles through the fuel to the upper portion of said pressure tank for onward transmission by the air pump.

16. Apparatus as defined in any of Claims 12-15 wherein said water level maintaining means comprises an electric circuit including a source of electromotive force, a pair of spaced apart electrodes in the lower portion of said pressure tank and an electrically operated valve in a water supply means, said circuit opening said valve to supply water to said tank in response to a signal from said electrodes.

17. Apparatus as defined in any of Claims 9-16 wherein said fuel oil supply means includes a float riding on the oil in said pressure tank and a valve actuated by said float to admit liquid fuel therein to a predetermined level and then to shut said valve.

18. Burner apparatus as defined in any of Claims 8-17 wherein said dispersed fuel burning means is of the gun type and a coil provides vaporized fuel formation means in that it is mounted in said combustion chamber so as to encircle an area in the path of the flame.

19. Apparatus as defined in any of Claims 13-16 wherein as well as said enriched vapor fuel supply means comprising said vapor burner tip in said combustion chamber, enriched vaporized fuel formation means is provided, comprising a liquid fuel line leading from the oil burner of said unit through the combustion chamber of said unit to an outlet beneath the level of the water in said pressure tank to produce heated oil bubbles therein for rising upwardly through said layers of water and oil into an upper chamber of said pressure tank; and air pressure supply means is arranged to maintain predetermined air pressure in said pressure tank.

20. Apparatus as defined in Claim 18 comprising a pump for periodically drawing liquid oil as fuel into said pressure tank and arranged for pumping it to the burner tip of said unit while maintaining the thickness of the layer of oil in the pressure tank, and for simultaneously pumping a diverted portion of said liquid fuel oil from said burner through said heating coil in said combustion chamber and thence to an outlet beneath the level of said water in said pressure tank to cause heated bubbling and turbulence therein, thereby enriched vapor is formed in the upper portion of said tank; and means for simultaneously directing a pressurized flow of said enriched vapor from said upper portion into said combustion chamber.

21. A fuel conditioning and burning process or apparatus substantially as described herein with reference to Figures 1 to 5 or Figures 6 and 7 of the accompanying drawings.