WO2011009872A1

WO2011009872A1 - A vaporizer reactor vessel and burner assembly

Info

Publication number: WO2011009872A1
Application number: PCT/EP2010/060507
Authority: WO
Inventors: Thomas Gerard Mimnagh
Original assignee: Thomas Gerard Mimnagh
Priority date: 2009-07-20
Filing date: 2010-07-20
Publication date: 2011-01-27
Also published as: EP2457021A1

Abstract

A vaporizer reactor vessel (51 ) includes a vaporizing chamber (52) having a fuel oil inlet (53) and a fuel vapour outlet (54). A jet (55) is mounted at the outlet (54). A heater (8) mounted within the chamber (52) is operable to heat fuel oil passing through the chamber (52) to a vaporizing temperature. A porous body of catalytic fuel conditioning material (56) is provided within the chamber (52) between the inlet (53) and the outlet (54) which is operable to inhibit deposition of carbonaceous material from the fuel. The jet (55) discharges into a cylindrical tube burner (60) having circumferential outlet slits (62) through which the fuel vapour and air is discharged for combustion.

Description

"A vaporizer reactor vessel and burner assembly" Introduction This invention relates to the vaporization of liquid fuels and to burner assemblies for heating, cooking, lighting and cleaning appliances utilising such gasified fuels. The invention particularly relates to blue flame burners.

Summary of the Invention

According to the invention there is provided a burner assembly including a burner and an associated vaporizer reactor vessel including a vaporizing chamber having a fuel oil inlet for connection to a liquid fuel supply and a fuel vapour outlet with a jet for discharging fuel vapour to the burner, and a heater operable to heat an interior of the chamber to a temperature sufficient to vaporize the fuel oil, characterised in that a porous body of catalytic fuel conditioning material is packed within the chamber between the inlet and the outlet, said catalytic fuel conditioning material being operable to inhibit deposition of carbonaceous material from the fuel. In one embodiment the fuel conditioning material comprises a plurality of pellets shaped to provide voids between said pellets when they are packed in the chamber for through passage of fuel.

In another embodiment means is provided for controlling the temperature within the chamber, said means comprising a thermocouple mounted within the chamber and connected to a controller for regulating operation of the heater in response to the sensed temperature within the chamber.

In another embodiment the burner assembly includes a fuel pump having an inlet for connection to a fuel oil supply and an outlet connected to the inlet of the reactor vessel, a fuel supply control valve is mounted between the pump outlet (34) and the reactor vessel inlet, said fuel supply control valve being operably connected to the controller for regulating operation of the control valve. In another embodiment the burner comprises a tube burner. Preferably the tube burner has an inlet at one end, the jet being mounted at the inlet such that fuel vapour discharged from the jet draws in air through the inlet for mixing with the fuel vapour within the burner prior to discharge through an outlet of the burner.

In another embodiment the controller is operable to regulate operation of the fuel pump for controlling operation of the burner.

In another embodiment the vaporizer reactor vessel is formed by portion of a fuel line connected to the burner, said fuel line portion having a vaporizing heater for heating said fuel line portion to a fuel vaporizing temperature and said fuel line portion containing the porous of catalytic fuel conditioning material within said fuel line portion. In another embodiment the vaporizing heater is formed by the burner, said fuel line portion being mounted adjacent to the burner in a position to receive radiant heat from the burner during operation of the burner.

In another embodiment a fan is provided which is operable to deliver air to the burner together with the fuel vapour.

In another embodiment the fuel conditioning material comprises aluminium oxide.

In another embodiment the fuel conditioning material is selected from the group comprising zeolite, aluminium hydrosilicate, treated bentonite clay, Fullers earth, bauxite and silka-alumina.

In another embodiment the pellets have a cylindrical shape. According to another aspect of the invention there is provided a vaporizer reactor vessel including a vaporizing chamber having a fuel oil inlet and a fuel vapour outlet, and a heater operable to heat an interior of the chamber to a temperature sufficient to vaporize the oil, characterised in that a porous fuel conditioning material is packed within the chamber between the inlet and the outlet. In one embodiment of the invention said fuel conditioning material is operable to inhibit deposition of carbonaceous material from the fuel within the chamber. In another embodiment the fuel conditioning material comprises a plurality of pellets shaped to provide voids between said pellets when they are packed in the chamber for through passage of fuel.

In another embodiment the pellets have a generally cylindrical shape. Conveniently the pellets may have a diameter of about 2mm and a length of about 5 mm.

In an alternative arrangement the pellets have a generally spherical shape. Other suitable shapes may also be used. In a particularly preferred embodiment the fuel conditioning material comprises aluminium oxide. Alternatively, the fuel conditioning material is selected from the group comprising zeolite, aluminium hydrosilicate, treated bentonite clay, Fullers earth, bauxite and silka-alumina. In another embodiment means is provided for controlling the temperature within the chamber. Conveniently, said means is a thermocouple mounted within the chamber and connected to a controller for regulating operation of the heating means in response to the sensed temperature within the chamber. In another embodiment, the fuel conditioning material has a honeycomb structure. This advantageously provides a relatively large surface area for heat transfer to the fuel oil for vaporizing the fuel oil.

In another embodiment, the fuel conditioning material comprises a body formed of a sintered metal material such as bronze, brass or copper, for example. The fuel conditioning material may comprise pieces or pellets of the sintered metal material.

In another embodiment, the body is generally cylindrical in shape having a central opening within which is nested a heating element which forms the heater. In a further embodiment, the chamber is cylindrical, the body being a snug fit within the chamber so that fuel oil is directed through the body as it travels between the inlet and the outlet of the chamber, the chamber having an enlarged inlet end defining an annular space encircling an inlet end of the body. Thus, fuel oil has access all around an inlet end of the body for efficient and even delivery of fuel oil through the body.

In a further embodiment, a jet is mounted at or adjacent the outlet of the chamber. In another embodiment a temperature sensor is provided for sensing the temperature within the chamber, the temperature sensor and the heater being connected to a controller, said controller being operable to regulate operation of the heater in response to the sensed temperature within the chamber. In another aspect the invention provides a fuel vaporizing system comprising the reactor vessel in combination with a fuel pump having an inlet for connection to a fuel oil supply and an outlet connected to the inlet of the reactor vessel.

In another embodiment a fuel supply control valve is mounted between the pump outlet and the reactor vessel inlet, said fuel supply control valve being operably connected to the controller for regulating operation of the control valve.

In another embodiment of the invention, there is provided a burner assembly, comprising:

vaporizing means arranged to provide a vaporized fuel at an outlet thereof; and a burner having an inlet, wherein the inlet is in fuel communication with the outlet of the vaporizing means, the burner comprising means for premixing the vaporized fuel with air at the inlet prior to combustion. Suitably, the burner further comprises a perforated chamber into which the premixed air and fuel mixture is conveyed, wherein the mixture is ignited as it discharges through the perforated burner. The inlet may be provided at one end of the chamber. Preferably, the perforations are provided in the form of slits and/or holes provided circumferentially of the chamber.

In one embodiment, the burner is a tube burner. In other embodiments, the 5 burner may be a ceramic burner.

Ideally, the vaporized fuel is premixed with sufficient air at the inlet to support blue flame combustion. Ideally, no further air need be supplied to the burner. However, in certain embodiments supplementary air may be supplied, for 10 example, to enhance combustion. The air for premixing may be supplied by an air fan. The air fan may have the secondary purpose of directing the premixed fuel into the burner.

An advantage of this arrangement is that a burner which is conventionally used 15 for combustion of gas fuels such as a tube burner or ceramic burner, may be used in conjunction with a vaporized liquid fuel premixed with air to achieve blue flame combustion.

Blue flame combustion ensures high efficiency and low NOx emissions. The vaporized fuel may be provided to the burner at low pressure, ensuring safe

20 operation.

Suitably, the vaporizing means is arranged to vaporize a liquid fuel. The liquid fuel may be a liquid fuel oil. Any suitable fuel oil may be used, such as, for example, biofuels. In preferred embodiments, the vaporizing means comprises 25 a liquid fuel inlet and a fuel vapour outlet and a heating means operable to heat the liquid fuel to a temperature sufficient to vaporize the liquid, wherein a fuel conditioning material is provided between the inlet and the outlet.

In certain embodiments of the invention, the vaporizing means comprises the

30 vaporizer reactor vessel or the fuel vaporizing system described above.

Additionally, or alternatively, the vaporizing means may comprise a preheat surround (or economizer) tube having a fuel conditioning material provided therein. The surround tube may be arranged such that heat generated by combustion of the premixed fuel in the burner causes vaporization of the fuel in the surround tube. Preferably, the surround tube is arranged such that it is substantially adjacent to the burner. In a preferred embodiment, the surround tube is arranged such that it substantially encompasses or encircles at least a portion of the combustion chamber of the burner. In another embodiment, a heater may be provided adjacent to the surround tube to vaporize liquid fuel in the tube.

In one embodiment, the vaporizer reactor vessel or fuel vaporizing system may be used to vaporize the liquid fuel during start up. Furthermore, the vaporizer reactor vessel or fuel vaporizing system alone may be used to vaporize the fuel throughout operation of the burner assembly. However, ideally, and so as to enable economy, once steady-state operation has been reached, the surround tube may become the principal vaporizing means, allowing the vaporizer reactor vessel or fuel vaporizing system to be switched off .

In another embodiment of the invention, the vaporizing means may comprise a fuel line having a fuel conditioning material provided in a portion thereof and a heating means provided proximal or adjacent to said portion to vaporize liquid fuel in the fuel line. The heating means may be arranged such that the fuel line passes therethrough. In other embodiments, the heating means may be arranged within the fuel line.

Any of the fuel conditioning materials described above with reference to the vaporizer reactor vessel may be used in the surround tube or fuel line.

In a further aspect the invention provides a burner assembly incorporating the vaporizer reactor vessel or the fuel vaporizing system. In another embodiment the burner assembly includes a tube burner having an inlet at one end, the jet being mounted at the inlet such that fuel vapour discharged from the jet draws in air through in the inlet for mixing with the fuel vapour within the burner prior to discharge through an outlet of the burner. In another embodiment the controller is operable to regulate operation of the fuel pump for controlling operation of the burner.

In a further embodiment the controller is operable to switch off the burner if the heater fails or is switched off.

In a further aspect the invention provides a solid fuel affect oil fire incorporating the vaporizer reactor vessel or the fuel vaporizing system or the burner assembly described herein.

In another aspect the invention provides an internal combustion engine incorporating the vaporizer reactor vessel.

In a further aspect the invention provides a method of vaporizing a fuel oil including the step of heating the fuel oil to a vaporizing temperature in the presence of a fuel conditioning material which is operable to inhibit deposition of carbonaceous material from the fuel.

In another embodiment the fuel conditioning material is aluminium oxide.

In a further embodiment the fuel conditioning material is selected from the group comprising zeolite, aluminium hydrosilicate, treated bentonite clay, Fullers earth, bauxite and silka-alumina. Brief Description of the Drawings

The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:-

Fig. 1 is a schematic sectional elevational view of a vaporizer;

Fig. 2 is a schematic plan illustration of a burner assembly; Fig. 3 is a schematic illustration of a fuel effect oil fire;

Fig. 4 is a schematic illustration of a burner assembly incorporating a vaporizer reactor vessel according to another embodiment of the invention;

Fig. 5 is a schematic illustration of a burner assembly according to another embodiment of the invention;

Fig. 6 is a schematic illustration of a burner assembly according to a further embodiment of the invention; and

Fig. 7 is a schematic illustration of a burner assembly according to another embodiment of the invention.

Detailed Description of Preferred Embodiments

Referring to the drawings, and initially to Fig. 1 thereof, there is illustrated a vaporizer, indicated generally by the reference numeral 1. The vaporizer 1 has a generally cylindrical steel housing 2 having a fuel oil inlet 3 and a fuel vapour outlet 4, with, in this case, a jet 5 mounted at the outlet 4. The housing 2 contains a vaporizer unit 7 with an associated heater 8 for heating the vaporizer unit 7 so that fuel oil entering through the inlet 3 is vaporized and then discharged through the outlet 4. The housing 2 has an upper portion 10 and a lower portion 11. The vaporizer unit 7 is a snug fit within the upper portion 10 to ensure that fuel oil passes through the vaporizer unit 7 for vaporization. The lower portion 11 has a somewhat larger diameter than the upper portion 10 thus defining an annular space 14 extending around a lower end of the vaporizing unit 7 so that fuel oil will evenly flood and pass through the vaporizer unit 7. An end cover 15 seals a bottom of the housing 2.

The vaporizer unit 7 is generally cylindrical being formed in this case by sintered bronze material to provide a large heated metal surface for vaporizing fuel oil. The heating element 8 is nested within a central bore of the vaporizer unit 7 for heating the vaporizer unit 7 to a desired vaporizing temperature. A thermocouple 16 is embedded in the vaporizer unit 7 for monitoring the temperature of the vaporizer unit 7. Referring now to Fig. 2, there is shown a burner assembly, indicated generally by the reference numeral 20, incorporating the vaporizer ^"I .The burner assembly 20 comprises the vaporizer 1 in combination with a combustion manifold 21. The jet 5 of the vaporizer 1 discharges within the combustion manifold 21. An array of spaced- apart discharge slits 22 is provided in the manifold 21 so that vapour discharged into the manifold 21 from the jet 5 passes outwardly through the slits 22 for combustion.

Fig. 3 shows the burner assembly 20 with the vaporizer 1 incorporated in a solid fuel effect oil fire, indicated generally by the reference numeral 30. The fire assembly 30 has a pump 31 with an inlet 32 for connection to a liquid fuel oil supply such as a fuel oil reservoir tank 33. An outlet 34 of the pump 31 is connected by a fuel transfer line 35 with the vaporizer 1 inlet 3. The fuel pump 31 creates a desired fuel pressure to the vaporizer 1 and is electronically controlled. A fuel supply control oil valve 40 is mounted in the fuel line 35 communicating between the pump 31 and the inlet 3 of the vaporizer 1.

Mounted on a top surface 24 of the combustion manifold 21 is a pile of ceramic imitation coals 41. These coals 41 cover the slits 22 so that, in use, vapour from the manifold 21 passes up through the slits 22 and about the coals 41 igniting to form a solid fuel effect fire. Flames generated by combustion of the vapour heat up the ceramic imitation coals 41 which will glow red in the fashion of pieces of coal in a real fire.

To initiate combustion, a pair of electrodes 45 is mounted directly above the slits 22 and is operatively connected with a controller 46. A flame sensor 48 is also mounted adjacent the slits 22, being connected also to the controller 46.

The fuel supply control valve 40, the thermocouple 16 and the heater element 8 are all operatively connected to the controller 46 for operation of the fire 30 as described below. In use, the burner assembly 20 and coals 41 are mounted in a fireplace. Liquid fuel oil is delivered from the reservoir 33 by the pump 31 into the vaporizer 1 at the desired fuel pressure. The controller 46 regulates the supply of pressurised liquid fuel oil by regulating operation of the pump 31. Operation of the heating element 8 is regulated by the controller 46 to heat the vaporizer unit 7 to a desired vaporizing temperature. The thermocouple 16 senses the temperature and with the controller 46 enables regulation of the operation of the heating element 8 to maintain a desired vaporizing temperature within the vaporizer 1. Fuel oil passing through the vaporizer 1 is vaporized and discharged through the jet 5 into the combustion manifold 21. As fuel vapour is discharged through the slits 21 in the top 24 of the combustion manifold 21 , it is ignited with the flames passing around and embracing the ceramic imitation coals 41 to imitate a real coal fire. To initiate combustion, a spark is delivered across the electrodes 45 by the controller 46. The flame sensor 48 ensures the presence of a flame when vapour is being discharged from the manifold 21 and if not the controller 46 shuts off the fuel supply valve 40. It will be appreciated that the vaporizer 1 essentially comprises a steel container or housing 2 within which an electrical heater 8 is surrounded by a heat-exchanging core or vaporizing unit 7 of sintered bronze material. The temperature within the housing 2 is totally controlled by means of the thermocouple 16 for optimum vaporization. The vaporizer 1 is primarily intended to heat kerosene oil, home heating oil, or diesel up to a point where it is a fully vaporized gas. It will also be noted that the honeycombed structure provided by the sintered bronze vaporizer unit 7 is particularly advantageous for vaporizing the liquid fuel oil. The honeycombed structure may be provided in any suitable fashion. It has been found that sintered bronze, brass or copper are suitable. These materials have the ability to heat up quickly, retain heat and readily transfer heat to the fuel to produce a vaporized gas for combustion.

The vaporizer 1 could be used in a wide range of oil burners which, for example, could be used in water heaters, water boilers, cookers, stoves, radiant heaters, hobs and industrial heaters and furnaces and other heating and lighting products. The vaporizer may also find application in steam cleaners. The invention may be applied to engines generally run on liquid fuels such as internal combustion engines used in motor vehicles, electrical generators and the like or for powering various other machines where a liquid fuel needs to be vaporized prior to combustion to generate power.

Referring now to Fig. 4 there is shown a blue flame low pressure oil burner assembly incorporating a vaporizer rector vessel according to the invention indicated generally by the reference numeral 50. The burner assembly 50 includes a cylindrical vaporizer reactor vessel 51 having an internal vaporizing chamber 52 with a liquid fuel inlet 53 and a fuel vapour outlet 54 with a jet 55 mounted at the outlet 54. In this case to form the vaporizer unit, the heater 8 within the chamber 52 is surrounded by pellets 56 of aluminium oxide. These pellets 56 are generally cylindrical having a diameter of about 2mm and a length of about 5mm. Thus the pellets 56 form a porous packing material within the chamber 52. In addition, the pellets 56 themselves are porous. The heater 8 is operable to heat an interior of the chamber 52 to a temperature sufficient to vaporize a liquid fuel delivered through the chamber 52 between the inlet 53 and the outlet 54.

The jet 55 discharges a hot stream of fuel vapour within a cylindrical tube burner 60 at the same time drawing in air through an inlet 61 of the burner 60 at one end of the burner 60 for mixing with the fuel vapour. The fuel vapour and air mixture discharges from the burner 60 through a plurality of circumferential outlet slits 62 and is ignited as it discharges from the burner 60. Electrodes 63 for igniting the fuel vapour initially are provided on the burner 60. The burner assembly 50 can conveniently be modulated from a minimum to a maximum setting as required by controlling operation of the fuel pump 31. Liquid fuel is delivered from a fuel tank (not shown) through a fuel line 66 to a fuel pump 31. The fuel pump 31 pumps the liquid fuel through a solenoid operated fuel supply control valve 40 to the inlet 53 of the vaporizer reactor vessel 51.

The start-up sequence is as follows: 1. Heater 8 is switched on and brought to the desired temperature.

2. Fuel supply control valve 40 opens.

3. Fuel pump 31 starts.

4. Electrodes 63 are operated to ignite vapour at the burner 60.

5. Burner 60 continues to run when flame is present and shuts in event of flame failure.

The controller 46 controls temperature parameters before allowing the other operations to take place. It includes a safety feature such that if the heater fails, it will shut down the burner. Another feature is an economy mode in which the power supply to the heater is initially high to bring the vaporizer reactor vessel up to the required operating temperature quickly and then is reduced in the economy mode. Referring now to Figure 5, there is illustrated a burner assembly 500 according to another embodiment of the present invention. The burner assembly 500 comprises a liquid fuel supply line 540 connected between a fuel oil reservoir tank (not shown) and a fuel pump 550. The fuel pump 550 is connected through a fuel supply control valve 560 to a preheat surround tube 570 having a fuel conditioning material (not shown) provided therein.

The burner assembly further comprises a vaporizer reactor vessel 510 having an internal vaporizing chamber 511 with a liquid fuel inlet 512 and a fuel vapour outlet 513. A nozzle 514 is mounted at the fuel vapour outlet 573. A heater 515 is operable to heat an interior of the chamber 511 to a temperature sufficient to vaporize a liquid fuel delivered through the chamber 511 between the liquid fuel inlet 512 and the fuel vapour outlet 513.

The nozzle 514 is in fluid communication with an inlet 521 of a tube burner 520. An air fan 525 is also in fluid communication with the nozzle 514 to premix the vaporized fuel oil with air at the inlet 521 of the tube burner 520. The tube burner 520 comprises a perforated cylindrical chamber 522 into which the premixed air and fuel mixture is conveyed. The perforations are provided in the form of slits 523 provided circumferentially on the chamber 522. The air flow from the fan 525 forces the air and fuel into the burner chamber 522. The burner 520 further comprises an ignitor 524 in the form of electrodes or other similar means to ignite the mixture of fuel and air as it is discharged from the burner perforated chamber 522 through the slits 523. As shown, the preheat surround tube 570 is arranged such that it surrounds the combustion chamber 522 of the tube burner 520.

The burner assembly 500 further comprises a controller 580 having a plurality of control outputs 581-585 which may be used to control operation of the fuel pump 550, the fuel supply control valve 560, the heater 515, the ignitor 524 and the fan 525, respectively.

In use, liquid fuel is delivered from a fuel tank through the fuel line 540 to the fuel pump 550. The fuel pump 550 pumps the liquid fuel through the open control valve 560 into the preheat surround tube 570. The fuel is then supplied to the vaporizer reactor vessel 510. The heater 515 heats the interior of the vaporizing chamber 511 to vaporize the liquid fuel. The heater 515 may be turned on in advance of supply of fuel to the vaporizer reactor vessel 510 to allow the desired temperature to be reached. Vaporized fuel discharged through the fuel vapour outlet 513 flows through the nozzle 514 and is premixed with air from the fan 525 at the inlet 521 of the burner 520. To initiate combustion the ignitor 524 is operated to ignite the mixture of fuel and air as it is discharged from the slits 523 of the tube burner 520.

Once operation has been established, the heat from combustion of the premixed fuel in the tube burner 520 is sufficient to vaporize the liquid fuel in the surround tube 570, and the heater 515 may therefore be switched off, thus improving the operating efficiency.

Figure 6 illustrates a burner assembly 600 according to another embodiment of the present invention. The burner assembly 600 comprises a liquid fuel supply line 640 connected between a fuel oil reservoir tank (not shown) and a fuel pump 650. The fuel pump 650 is connected through a fuel supply control valve 660 to a nozzle 614.

A vaporizing heater 615 is arranged adjacent a portion of the fuel line 640 having a fuel conditioning material (not shown) provided therein. The vaporizing heater 615 is operable to heat liquid fuel in the fuel line 640 to a temperature sufficient to cause vaporization.

The nozzle 614 is in fluid communication with an inlet 621 of a tube burner 620. An air fan 625 is also in fluid communication with the nozzle 614 to premix the vaporized fuel oil with air at the inlet 621 of the burner 620. The tube burner 620 has a perforated cylindrical chamber 622, with perforation in the form of slits 623 provided circumferentially on the chamber 622. Operation of the tube burner 620 is as described above with reference to Figure 5. The burner assembly 600 further comprises a controller 680 having a plurality of control outputs 681 -685 which may be used to control operation of the fuel pump 650, the fuel supply control valve 660, the vaporizing heater 615, the ignitor 624 and the fan 625, respectively. In use, liquid fuel is delivered from a fuel tank through fuel supply line 640 to fuel pump 650. The fuel pump 650 pumps the liquid fuel through the control valve 660 and through the portion of the fuel line having the fuel conditioning material provided therein. The heater 615 heats this portion of the fuel line to vaporize the liquid fuel. The heater 615 may be turned on in advance of supply of fuel to the fuel line to allow the desired temperature to be reached. The vaporized fuel flows through the nozzle 614 and is premixed with air from the fan 625 at the inlet 621 of the burner 620. At start-up to initiate combustion the ignitor 624 is operated to ignite the mixture of fuel and air as it is discharged from the slits 623. Referring now to Fig. 7 there is shown another burner assembly according to the invention indicated generally by the reference numeral 700. Parts similar to those described previously have been assigned the same reference numerals. This is largely similar to the burner assembly 500 shown in Fig. 5. However, in this case the vaporizer reactor vessel 510 shown in Fig. 5 has been replaced by the vaporizing heater 615 which is mounted on the pre-heat surround tube 570 and operated initially to vaporize the liquid fuel in the presence of the catalyst material and then being switched off when the heat generated by the tube burner 620 in operation is sufficient to cause the liquid fuel to vaporize in the pre-heat surround tube 570 in the presence of the catalyst material before delivery to the nozzle 614. It will be appreciated that the invention provides a premixed blue flame low pressure oil burner. The burner produces a high temperature clean blue flame which can be visually compared to existing gas burners. This burner operates at a very low pressure which reduces operating noise to a minimum. The premixed burner automatically adjusts to its own air requirements. The technology can also be used in semi-mixed burners, ceramic gas burners, and ceramic radiant burners.

The small size of the new burner will not only reduce the physical size of the heating product but will also reduce fuel usage. The result will be a clean burning, low emissions unit (NOx and carbon dioxide) with extremely high efficiency.

A further aspect of the invention is that it can be modulated from a minimum to a maximum setting depending on the kW output of the products e.g. oil boilers, cookers, stoves, furnaces, space heaters radiant, process heating, camping and marine, oil flame fires, domestic and commercial.

Vaporization takes place in the presence of a catalyst used for the reforming of oil, e.g. aluminium oxide or any other catalyst (in this regard other possible catalysts include zeolite, aluminium hydrosilicate, treated bentonite clays, Fullers earth, bauxite and silka-alumina). The heated catalyst reacts with fuel oil to improve the transition of oil to the gas phase and eliminates the problem of cracking or coaking. It also improves the thermal transfer of heat to the fluid. It has been shown to significantly reduce NOx and the carbon dioxide of the burnt fuel.

It will be appreciated that the vaporizer reactor vessel of the invention can be used in a wide range of applications wherever liquid fuels need to be vaporized for combustion. This will include various burner assemblies used in heating and lighting applications and also in connection with internal combustion engines such as are used in automotive applications, electricity generation etc. It will be noted that the vaporizer reactor vessel of the invention provides a very clean burning, low emission (NOx and Carbon Dioxide) vapour fuel with extremely high efficiency. The vaporizer reactor vessel of the invention can be used with various liquid fuels, including kerosene, diesel, bio fuels etc. It is also envisaged that the fuel oil may be further treated by fuel conditioning material upstream of the vaporizer reactor vessel, possibly in a filter or the like device.

The words "comprises/comprising" and the words "having/including" when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail within the scope of the appended claims.

Claims

1. A burner assembly (50) including a burner (60) and an associated vaporizer reactor vessel (51) including a vaporizing chamber (52) having a fuel oil inlet (53) for connection to a liquid fuel supply and a fuel vapour outlet (54) with a jet

(55) for discharging fuel vapour to the burner (6), and a heater (8) operable to heat an interior of the chamber (52) to a temperature sufficient to vaporize the fuel oil, characterised in that a porous body of catalytic fuel conditioning material (56) is packed within the chamber (52) between the inlet (53) and the outlet (54), said catalytic fuel conditioning material (56) being operable to inhibit deposition of carbonaceous material from the fuel.

2. The burner assembly (50) as claimed in claim 1 wherein the fuel conditioning material (56) comprises a plurality of pellets shaped to provide voids between said pellets when they are packed in the chamber (52) for through passage of fuel.

3. The burner assembly (50) as claimed in any preceding claim wherein means is provided for controlling the temperature within the chamber (52), said means comprising a thermocouple (16) mounted within the chamber (52) and connected to a controller (46) for regulating operation of the heater (8) in response to the sensed temperature within the chamber (52).

4. The burner assembly (50) as claimed in claim 3 further including a fuel pump (31 ) having an inlet (32) for connection to a fuel oil supply (33) and an outlet

(34) connected to the inlet (53) of the reactor vessel (51), a fuel supply control valve (40) is mounted between the pump outlet (34) and the reactor vessel inlet (51), said fuel supply control valve (40) being operably connected to the controller (46) for regulating operation of the control valve (40).

5. The burner assembly (50) as claimed in any preceding claim wherein the burner comprises a tube burner (60). Inlet (61) at one end, the jet (55).

6. The burner assembly as claimed in claim 5 wherein the burner (60) has been mounted at the inlet (61) such that fuel vapour discharged from the jet (55) draws in air through the inlet (61) for mixing with the fuel vapour within the burner (60) prior to discharge through an outlet (62) of the burner (60).

7. The burner assembly (50) as claimed in any of claims 4 to 6 wherein the controller (46) is operable to regulate operation of the fuel pump (31) for controlling operation of the burner (60).

8. The burner assembly (600) as claimed in any preceding claim wherein the vaporizer reactor vessel is formed by portion of a fuel line (640) connected to the burner (620), said fuel line portion having a vaporizing heater (615) for heating said fuel line portion to a fuel vaporizing temperature and said fuel line portion containing the porous of catalytic fuel conditioning material within said fuel line portion.

9. The burner assembly (500) as claimed in claim 8 wherein the vaporizing heater is formed by the burner (520), said fuel line portion (570) being mounted adjacent to the burner (520) in a position to receive radiant heat from the burner (520) during operation of the burner (520).

10. The burner assembly (500) as claimed in any preceding claim wherein a fan (525) is provided which is operable to deliver air to the burner (520) together with the fuel vapour.

11. The burner assembly (50) as claimed in any preceding claim wherein the fuel conditioning material (56) comprises aluminium oxide.

12. The burner assembly (50) as claimed in any one of claims 1 to 10 wherein the fuel conditioning material (56) is selected from the group comprising zeolite, aluminium hydrosilicate, treated bentonite clay, Fullers earth, bauxite and silka- alumina.

13. The burner assembly as claimed in any one of claims 2 to 12 wherein the pellets have a cylindrical shape.

14. The burner assembly as claimed in claim 13 wherein the pellets have a diameter of 2mm and a length of 5mm.

15. The burner assembly as claimed in any of claims 2 to 12 wherein the pellets have a spherical shape.

16. The burner assembly as claimed in any preceding claim, comprising:

vaporizing means arranged to provide a vaporized fuel at an outlet thereof; and a burner having an inlet, wherein the inlet is in fluid communication with the outlet of the vaporizing means, the burner comprising means for premixing the vaporized fuel air with air at the inlet prior to combustion.

17. The burner assembly as claimed in claim 16 wherein the burner further comprises a perforated chamber into which the premixed air and fuel mixture is conveyed, wherein the mixture is ignited as it is discharged from the burner through the perforations.

18. The burner assembly as claimed in claim 16 or claim 17, wherein the means for premixing comprising means for premixing the vaporized fuel oil with sufficient air at the inlet to support blue flame combustion.

19. The burner assembly as claimed in any of claims 16 to 18, wherein the vaporizing means comprises a liquid fuel inlet and a fuel vapour outlet and a heating means operable to heat the liquid fuel to a temperature sufficient to vaporize the liquid, wherein a fuel conditioning material is provided between the inlet and the outlet.

20. A vaporizer reactor vessel including a vaporizing chamber having a fuel oil inlet and a fuel vapour outlet, and a heater operable to heat an interior of the chamber to a temperature sufficient to vaporize the fuel oil, characterised in a that a porous body of fuel conditioning material is packed within the chamber between the inlet and the outlet, said catalytic fuel conditioning material being operable to inhibit deposition of carbonaceous material from the fuel within the chamber.

21. The reactor vessel as claimed in claim 20 wherein the fuel conditioning material comprises aluminium oxide.

22. The reactor vessel as claimed in claim 20 wherein the fuel conditioning material is selected from the group comprising zeolite, aluminium hydrosilicate, treated bentonite clay, Fullers earth, bauxite and silka-alumina.

23. The reactor vessel as claimed in any one of claims 20 to 22 wherein the fuel conditioning material comprises a plurality of pellets shaped to provide voids between said pellets when they are packed in the chamber for through passage of fuel.

24. The reactor vessel as claimed in claim 23 wherein the pellets have a generally cylindrical shape.

25. The reactor vessel as claimed in claim 23 or claim 24 wherein the pellets have a diameter of about 2mm and a length of about 5 mm.

26. The reactor vessel as claimed in claim 23 wherein the pellets have a generally spherical shape.

27. The reactor vessel as claimed in any one of claims 20 to 26 wherein means is provided for controlling the temperature within the chamber.

28. The reactor vessel as claimed in claim 27 wherein said means is a thermocouple mounted within the chamber and connected to a controller for regulating operation of the heater in response to the sensed temperature within the chamber.

29. A fuel vaporizing system comprising the reactor vessel as claimed in any of claims 19 to 27 in combination with a fuel pump having an inlet for connection to a fuel oil supply and an outlet connected to the inlet of the reactor vessel.

30. The fuel vaporising system as claimed in claim 29 wherein a fuel supply control valve is mounted between the pump outlet and the reactor vessel inlet, said fuel supply control valve being operably connected to the controller for regulating operation of the control valve.

31. A solid fuel effect oil fire incorporating the burner assembly as claimed in any of claims 1 to 19, or the vaporizer reactor vessel of claims 20 to 28 or the fuel vaporizing system of claims 29 or 30.