WO2016156868A1

WO2016156868A1 - Fuel atomizer

Info

Publication number: WO2016156868A1
Application number: PCT/GB2016/050927
Authority: WO
Inventors: Keith Bailey; Paul Newman; Nick James
Original assignee: Hamworthy Combustion Engineering Ltd.
Priority date: 2015-04-02
Filing date: 2016-04-01
Publication date: 2016-10-06
Also published as: GB2536965B; JP2016197001A; JP2018189362A

Abstract

An atomizer (210) for a burner comprising an atomization region (208), a proximal end (202) comprising at least one inlet configured to allow fuel and/or an atomizing medium to enter the atomization region (208), a distal end (204) comprising at least one outlet (226) configured to allow atomized fuel to exit the atomization region (208), wherein an external surface (228) of the distal end (204) is shaped to permit air flow around the at least one outlet (226).

Description

FUEL ATOM IZER

Field of the Invention

The invention relates to atomizers, particularly atomizers for use in fuel burners.

Background of the Invention

Burners, such as oil only or dual fuel (oil and gas) burners, usually have a single atomizer or a series of atomizers which use an atomizing medium, such as compressed gas (e.g. compressed air) or steam, to atomize the fuel. The atomizer(s) then project atomized fuel into a combustion region of the burner where a flame can be established on application of an ignition source.

Existing atomizers typically use inlets in the form of drilled or milled holes to introduce the fuel and the atomizing medium into an atomization region within the atomizer so that the atomizing medium breaks the fuel into small droplets (i.e. the atomizing medium "atomizes" the fuel). The atomizer then delivers the atomized fuel through a plurality of outlets into a combustion region of the burner.

Fig. 1 shows a typical "Y" jet atomizer 10 in use. A delivery system 12 is used to deliver fuel (such as oil or oil and gas mixtures) and an atomizing medium (such as steam or compressed gas (e.g. compressed air)) into the atomizer 10. The delivery system 12 comprises an inner tube 14, an outer tube 16 and a tube spacer 18 for spacing the outer tube 16 from the inner tube 14. The fuel is delivered into the atomizer 10 through a plurality of first inlets 20 and the atomizing medium is delivered into the atomizer 10 through a plurality of second inlets 22. Typically, fuel is delivered between the inner tube 14 and the outer tube 16, and the atomizing medium is delivered through the inner tube 14. In other words, the first inlets 20 are disposed radially outside the second inlets 22. Consequently, the fuel and the atomizing medium are brought into contact with each other within the atomizer 10 and this causes the fuel to break up into small droplets. A spray 24 of atomized fuel then exits the atomizer 10 through a plurality of outlets 26 and is delivered into a combustion region of a burner where a flame can be established on application of an ignition source (not shown) to the spray 24.

A typical atomizer 10 is shown in Fig. 2. It can be seen that the outlets 26 through which the atomized fuel spray 24 is allowed to exit the atomizer 10 take the form of drilled or milled holes through an external surface of the atomizer 10. The first 20 and second 22 inlets (not shown in Fig. 2) are located on the opposite side of the atomizer 10 to the outlets 26. Fig. 3 shows a cross-sectional view of a conventional Ύ" jet atomizer 10. As described above with reference to Figs. 1 and 2, the atomizer comprises a first inlet 20 through which fuel is delivered into the atomizer 10 and a second inlet 22 through which the atomizing medium is delivered into the atomizer 10. The fuel and the atomizing medium are brought into contact with each other within the atomizer 10 and this causes the fuel to break up into small droplets. The atomizer comprises a plurality of outlets 26 through which the atomized fuel then exits the atomizer 10 and enters a combustion region of a burner where a flame can be established on application of an ignition source (not shown) to the atomized fuel.

Many fired heating applications require oil or dual fuel burners to operate over a wide range of thermal input ratings. It is therefore advantageous to provide atomizers which operate efficiently over a wide range of fuel delivery rates. Typically, as the rate of flow of fuel into an atomizer is reduced, atomizing quality (which is measured by fuel oil droplet size; a smaller droplet size represents a higher atomizing quality) is maintained by increasing the rate of flow of atomizing medium into the atomizer. However, if the rate of delivery of fuel is decreased significantly, the combustion performance of the burner (as measured by flame stability, flue gas excess air levels and flame cohesion) often degrades to the point of flame extinction. This is a limitation of existing atomizer technology.

Another important measurement of the effectiveness of a burner is the "turndown" of the burner. The turndown is the ratio between the burner's maximum and minimum firing fuel flow. In other words, high turndown operation uses a greater flow of atomizing medium and a proportionally lesser flow of fuel. In contrast, low turndown operation uses a greater flow of fuel and a proportionally lesser flow of atomizing medium. Existing burners, such as those marketed by John Zink Hamworthy Combustion, offer a maximum turndown of 15: 1 (i.e. 15 times less fuel is used at turndown than at maximum firing rate). In certain applications, it would be advantageous to provide a burner having an improved turndown since this would result in a more efficient combustion system and, therefore, significantly reduced fuel and operating costs.

For instance, many ships carrying liquid natural gas as a cargo use boil off gases from the cargo in combination with fuel oil to propel the ship by firing these fuels in a burner into a boiler to produce steam for propulsion. In these circumstances of combined firing of the two fuels, it is advantageous to minimise the use of fuel oil, hence the reason that improved burner turndown on fuel oil is desired.

There is therefore a need for improved atomizers and burners. Summary of the Invention

In accordance with a first aspect of the invention, there is provided an atomizer for a burner comprising:

an atomization region;

a proximal end comprising at least one inlet configured to allow fuel and/or an atomizing medium to enter the atomization region;

a distal end comprising at least one outlet configured to allow atomized fuel to exit the atomization region,

wherein an external surface of the distal end is shaped to permit air flow around the at least one outlet.

It is advantageous to provide an atomizer which encourages and promotes uniform airflow between the outlets in a controlled manner (e.g. in a "swirling" pattern) because this allows for a more stable flame, even at high turndown operation. The external surface of the distal end may be shaped to control air flow (e.g. in a uniform manner) around the at least one outlet and/or between outlets. In other words, the external surface of the distal end may be shaped to guide the flow of air (e.g. in a uniform manner) around the at least one outlet and/or between outlets. In particular, the external surface of the distal end may be shaped to guide the flow of air in a swirling pattern.

The proximal end of the atomizer may comprise at least one first inlet configured to allow fuel to enter the atomization region and at least one second inlet configured to allow an atomizing medium to enter the atomization region.

The proximal end of the atomizer may comprise a plurality of first inlets (e.g. 7). The proximal end of the atomizer may comprise a plurality of second inlets (e.g. 7). The distal end of the atomizer may comprise a plurality of outlets (e.g. 7).

The external surface of the distal end may be shaped to permit air flow between the outlets. For example, the at least one outlet may protrude from the external surface of the distal end of the atomizer. The outlets may protrude from the external surface of the distal end of the atomizer at different orientations. Additionally or alternatively, the atomizer may comprise a channel, groove, cut, trough or indent between at least one outlet and at least one other outlet to permit air flow between the outlets. Shapes for the external surface of the distal end which permit air flow will also permit the flow of flue gas or mixtures of air and flue gas. The at least one outlet may comprise a bore defining an internal cross-section and a tube defining an external cross-section.

The internal cross-section and/or the external cross-section may be non-circular. The internal cross- section and the external cross-section may be non-circular. For example, the internal cross-section may be square, rectangular or curved. The external cross-section may be tear-shaped.

A non-circular first and/or second inlet is beneficial as it allows the atomizing medium and the fuel to come into contact with each other across a greater contact surface area than with the use of traditional circular milled or drilled holes. This results in better atomization and a greater contact surface area between the resulting atomized fuel and the combustion air in a burner that would typically be in fluid communication with the outlets of the atomizer. The use of non-circular first and/or second inlets therefore permits the burner to operate over a far greater load range than is possible using conventional atomizers whilst maintaining acceptable burner performance. Additionally, increased contact surface area between the atomizing medium and the fuel allows the outlets (see below) to be shaped more readily to deliver the atomized fuel droplets in any desired pattern without having an adverse effect on droplet size, thus improving the flexibility and robustness of the atomizer and associated burner.

The first inlet(s) may be disposed radially outside the second inlet(s). The first inlet(s) and the second inlet(s) may be configured to direct fuel entering the atomization region through the first inlet and atomizing medium entering the atomization region through the second inlet towards each other to atomize the fuel.

A proximal end of the atomizer may comprise a peripheral skirt with a recess disposed therein. An interior surface of the skirt may comprise a connection means, such as an internal thread. This facilitates connection of the atomizer to another element of a burner, such as a fuel and/or atomizing medium input means.

In accordance with another aspect of the invention, there is provided an atomizer for a burner comprising:

an atomization region;

a first inlet configured to allow fuel to enter the atomization region;

a second inlet configured to allow an atomizing medium to enter the atomization region; and an outlet configured to allow atomized fuel to exit the atomization region,

wherein the first inlet, the second inlet and/or the outlet comprises a bore having a non- circular cross-section. A non-circular first and/or second inlet is beneficial as it allows the atomizing medium and the fuel to come into contact with each other across a greater contact surface area than with the use of traditional circular milled or drilled holes. This results in better atomization and a greater contact surface area between the resulting atomized fuel and the combustion air in a burner that would typically be in fluid communication with the outlets of the atomizer. The use of non-circular first and/or second inlets therefore permits the burner to operate over a far greater load range than is possible using conventional atomizers whilst maintaining acceptable burner performance. Additionally, increased contact surface area between the atomizing medium and the fuel allows the outlets (see below) to be shaped more readily to deliver the atomized fuel droplets in any desired pattern without having an adverse effect on droplet size, thus improving the flexibility and robustness of the atomizer and associated burner.

At least two of the first inlet, the second inlet and the outlet may comprise a bore having a non- circular cross-section. All of the first inlet, the second inlet and the outlet may comprise a bore having a non-circular cross-section. The first inlet may have a square, rectangular or curved cross-section. The second inlet may have a square, rectangular or curved cross-section. The outlet may have a square, rectangular or curved cross-section.

The atomizer may further comprise a plurality of first inlets (e.g. 7). The atomizer may further comprise a plurality of second inlets (e.g. 7). The atomizer may further comprise a plurality of outlets (e.g. 7).

The atomizer may be manufactured using additive layer manufacturing (ALM). The atomizer may comprise a metal or a metal alloy. The atomizer may comprise Inconel 718, cobalt chrome or other available alloys. Compared with traditional techniques, 3-D printing techniques, such as ALM, allow very precise control of the shapes and dimensions of features of the atomizers, such as the cut-outs between the outlets, the protruding outlets and the non-circular shapes of the inlets and/or outlets. It is these features that allow the atomizers of the invention to have significantly improved performance compared with conventional atomizers. The fuel may comprise an oil or an oil and gas mixture. For example, the fuel may comprise diesel oil, marine gas oil, gas oil, low sulphur marine gas oil (LSMGO), heavy fuel oil (HFO), ultra low sulphur heavy fuel oil (ULSHFO) or any other liquid fuel. The atomizing medium may comprise compressed gas (e.g. compressed air) or steam.

There is also provided a burner comprising:

a combustion zone; and

an atomizer according to any aspect of the invention,

wherein the outlet of the atomizer is in fluid communication with the combustion zone and is configured to introduce atomized fuel into the combustion zone.

The combustion zone may be a primary combustion zone. The burner may further comprise a combustion stabilising device (e.g. a swirler, bluff body, or fluidic recirculation zone) that creates the combustion zone.

The burner may be a diesel burner or a HFO burner.

Brief Description of the Drawings

The invention will now be described with reference to the accompanying drawings in which:

Fig. 1 shows a known atomizer in use;

Fig. 2 shows a perspective view of a known atomizer;

Fig. 3 shows a cross-sectional view of a known atomizer;

Fig. 4 shows a perspective view of a first atomizer according to an embodiment of the invention; Fig. 5 shows a perspective view of a second atomizer according to an embodiment of the invention; Fig. 6 shows a view of an inlet side of the atomizer shown in Fig. 5; Fig. 7 shows a view of an outlet side of the atomizer shown in Fig. 5;

Fig. 8 shows a perspective view of a third atomizer according to an embodiment of the invention; Figs. 9 and 10 show combustion air flow patterns of the known atomizer shown in Fig. 2; Figs. 1 1 and 12 show combustion air flow patterns of the atomizer shown in Fig. 8; and Fig 13 shows a fourth atomizer according to an embodiment of the invention.

Detailed Description of the Drawings

Fig. 4 shows an atomizer 110 in accordance with a first embodiment of the invention. The atomizer 1 10 comprises a proximal end 102, a distal end 104 and a main body 106. The main body 106 defines an atomization region 108 within the atomizer 110 within which fuel is atomized.

The proximal end 102 of the atomizer 110 comprises at least one first inlet or, typically, a plurality of first inlets (not shown), as described above with respect to Figs. 1 to 3, which are configured to allow fuel to enter the atomization region 108 within the atomizer 1 10. The proximal end 102 of the atomizer 1 10 also comprises at least one second inlet or, typically, a plurality of second inlets (not shown), as described above with respect to Figs. 1 to 3, which are configured to allow an atomizing medium, such as steam or compressed gas (e.g. compressed air), to enter the atomization region 108 within the atomizer 1 10. The purpose of the atomizing medium is to break the fuel into small droplets when the fuel and the atomizing medium are brought into contact with each other within the atomization region 108; in other words, the atomizing medium "atomizes" the fuel. The first inlets and the second inlets are configured to direct fuel entering the atomization region 108 through the first inlets and atomizing medium entering the atomization region 108 through the second inlets towards each other to atomize the fuel.

The distal end 104 of the atomizer 1 10 comprises at least one outlet 126 or, typically, a plurality of outlets 126 through which a spray of atomized fuel exits the atomizer 110. The atomizer 110 shown in Fig. 4 comprises seven outlets 126. The outlets 126 are in fluid communication with a primary combustion zone of a burner (not shown) and the spray of atomized fuel typically enters the primary combustion zone once it has exited the atomizer 1 10 through the outlets 126. As shown in Fig. 4, the outlets 126 protrude from an external surface 128 of the distal end 104 of the atomizer, typically at different orientations. In other words, the atomizer 110 comprises a surface cutout 130 in the form of a channel, groove, cut, trough or indent in the external surface 128 between at least one outlet 126 and at least one other outlet 126, or substantially surrounding the outlets 126 as shown in Fig. 4. In the embodiment shown in Fig. 4, the outlets 126 protrude from the external surface 128 of the distal end 104 so that they are proud of the distal end 104. This permits a better flow of combustion air between the outlets 126 when compared with a simple milled or drilled "hole" arrangement such as those shown in Figs. 1 to 3. In the embodiment shown in Fig. 4, the outlets comprise a bore or lumen 132 defining an internal cross-section and a tube 134 (i.e. the "body" of the outlet) defining an external cross-section.

Figs. 5 to 7 show another atomizer 210 according to an embodiment of the invention. The atomizer 210 comprises a proximal end 202, a distal end 204 and a main body 206. The main body 206 defines an atomization region 208 within the atomizer 210 within which fuel is atomized.

The proximal end 202 of the atomizer 210 comprises at least one first inlet 220 or, typically, a plurality of first inlets 220 (as shown in Fig. 6), which are configured to allow fuel to enter the atomization region 208 within the atomizer 210. The proximal end 202 of the atomizer 210 also comprises at least one second inlet 222 or, typically, a plurality of second inlets 222 (as shown in Fig. 6), which are configured to allow an atomizing medium, such as steam or compressed gas (e.g. compressed air), to enter the atomization region 208 within the atomizer 210. The atomizer 210 shown in Fig. 6 comprises seven first inlets 220 and seven second inlets 222. The purpose of the atomizing medium is to break the fuel into small droplets when the fuel and the atomizing medium are brought into contact with each other within the atomization region 208; in other words, the atomizing medium "atomizes" the fuel. The first inlets 220 and the second inlets 222 are configured to direct fuel entering the atomization region 208 through the first inlets 220 and atomizing medium entering the atomization region 208 through the second inlets 222 towards each other to atomize the fuel.

As shown in Fig. 6, the first inlets 220 are disposed radially outside the second inlets 222. Additionally, in the exemplary embodiment shown in Fig. 6, the first 220 and second 222 inlets comprise a bore having a non-circular cross-section, such as a square, rectangular or curved cross- section. Any other suitable cross-sectional shape can also be used. A non-circular first and/or second inlet is beneficial as it allows the atomizing medium and the fuel to come into contact with each other across a greater contact surface area than with the use of traditional circular milled or drilled holes. This results in better atomization and a greater contact surface area between the resulting atomized fuel and the combustion air in a burner that would typically be in fluid communication with the outlets of the atomizer. The use of non-circular first and/or second inlets therefore permits the burner to operate over a far greater load range than is possible using conventional atomizers whilst maintaining acceptable burner performance. Additionally, increased contact surface area between the atomizing medium and the fuel allows the outlets (see below) to be shaped more readily to deliver the atomized fuel droplets in any desired pattern without having an adverse effect on droplet size, thus improving the flexibility and robustness of the atomizer and associated burner.

As shown in Figs. 5 and 7, the distal end 204 of the atomizer 210 comprises at least one outlet 226 or, typically, a plurality of outlets 226 through which a spray of atomized fuel exits the atomizer 210. The atomizer shown in Figs. 5 and 7 comprises seven outlets. The outlets 226 are in fluid communication with a primary combustion zone of a burner (not shown) and the spray of atomized fuel typically enters the primary combustion zone once it has exited the atomizer 210 through the outlets 226.

As shown in Figs. 5 and 7, the outlets 226 protrude from an external surface 228 of the distal end 204 of the atomizer, typically at different orientations. In other words, the atomizer 210 comprises a surface cut-out 230 in the form of a channel, groove, cut, trough or indent in the external surface 228 between at least one outlet 226 and at least one other outlet 226, or surrounding the outlets 226 as shown in Figs. 5 and 7. In the embodiment shown in Figs. 5 and 7, the outlets 226 protrude from the external surface 228 of the distal end 204 so that they are proud of the distal end 204. This permits a better flow of combustion air between the outlets 226 when compared with a simple milled or drilled "hole" arrangement such as those shown in Figs. 1 to 3.

In the embodiment shown in Figs. 5 and 7, the outlets comprise a bore or lumen 232 defining an internal cross-section and a tube 234 (i.e. the "body" of the outlet) defining an external cross-section. The internal cross-section and external cross-section are non-circular (e.g. square, rectangular, curved or any other suitable shape) and are shaped to improve the flow of combustion air between the outlets 226.

Fig. 8 shows another atomizer 310 according to an embodiment of the invention. The atomizer 310 comprises a proximal end 302, a distal end 304 and a main body 306. The main body 306 defines an atomization region 308 within the atomizer 310 within which fuel is atomized.

The proximal end 302 of the atomizer 310 comprises at least one first inlet or, typically, a plurality of first inlets (not shown), which are configured to allow fuel to enter the atomization region 308 within the atomizer 310. The proximal end 302 of the atomizer 310 also comprises at least one second inlet or, typically, a plurality of second inlets (not shown), which are configured to allow an atomizing medium, such as steam or compressed gas (e.g. compressed air), to enter the atomization region 308 within the atomizer 310. The first inlets and second inlets can be circular, as shown in Figs. 1 to 3, or non-circular, as shown in Fig. 6. The purpose of the atomizing medium is to break the fuel into small droplets when the fuel and the atomizing medium are brought into contact with each other within the atomization region 308; in other words, the atomizing medium "atomizes" the fuel. The first inlets and the second inlets are configured to direct fuel entering the atomization region 308 through the first inlets and atomizing medium entering the atomization region 308 through the second inlets towards each other to atomize the fuel. The first inlets are typically disposed radially outside the second inlets, as described above.

As shown in Fig. 8, the distal end 304 of the atomizer 310 comprises at least one outlet 326 or, typically, a plurality of outlets 326 through which a spray of atomized fuel exits the atomizer 310. The atomizer shown in Fig. 8 comprises seven outlets. The outlets 326 are in fluid communication with a primary combustion zone of a burner (not shown) and the spray of atomized fuel typically enters the primary combustion zone once it has exited the atomizer 310 through the outlets 326.

As shown in Fig. 8, the outlets 326 protrude from an external surface 328 of the distal end 304 of the atomizer, typically at different orientations. In other words, the atomizer 310 comprises a surface cutout 330 in the form of a channel, groove, cut, trough or indent in the external surface 328 between at least one outlet 326 and at least one other outlet 326, or surrounding the outlets 326 as shown in Fig. 8. In the embodiment shown in Fig. 8, the outlets 326 protrude from the external surface 328 of the distal end 304 so that they are proud of the distal end 304. This permits a better flow of combustion air between the outlets 326 when compared with a simple milled or drilled "hole" arrangement such as those shown in Figs. 1 to 3.

In the embodiment shown in Fig. 8, the outlets comprise a bore or lumen 332 defining an internal cross-section and a tube 334 (i.e. the "body" of the outlet) defining an external cross-section. The internal cross-section and external cross-section are non-circular (e.g. square, rectangular, curved or any other suitable shape) and are shaped to improve the flow of combustion air between the outlets 326. In the embodiment shown in Fig. 8, the internal cross-section is in the shape of a curved slot, which provides an improved spray pattern of atomized fuel. Additionally, the external cross- section is "tear-shaped" or "aerofoil-shaped" which provides a significantly improved flow of combustion air between the outlets 326. The external surface of the distal end is shaped to control air flow (e.g. in a uniform manner) around the outlets and/or between outlets. In other words, the external surface of the distal end is shaped to guide the flow of air (e.g. in a uniform manner) around the outlets and/or between outlets. In particular, the external surface of the distal end is shaped to guide the flow of air in a swirling pattern. Figs. 9 to 12 show air flow diagrams which demonstrate the improved air flow around the outlets that is achieved by i) providing outlets which protrude from the distal end of the atomizer and/or ii) providing outlets having non-circular cross-sections. Figs. 9 and 10 show air flow diagrams for the conventional atomizers 10 shown in Figs. 1 to 3 in which the outlets 26 are simply milled or drilled holes. Fig. 10 is an enlarged view of the centre of Fig. 9. Figs. 11 and 12 show air flow diagrams for the atomizer 310 shown in Fig. 8. Fig. 12 is an enlarged view of the centre of Fig. 11. As can be seen from Figs. 9 and 10, the air flow across the conventional atomizer 10 is generally in a single direction across the atomizer 10 face and radiates outwards. When used in conjunction with a burner, this would cause a biased flame front which would result in instability under high turndown operation (i.e. a low ratio of fuel to atomizing medium). In contrast, Figs. 1 1 and 12 show that the air flow across the atomizer 310 shown in Fig. 8 has a strong velocity profile flowing into the centre of the atomizer 310. There is an even swirl of air across the atomizer 310 face towards the centre. This provides an even combustion airflow at the base of a flame in a burner and, therefore, stability even under high turndown operation.

Fig. 13 shows a further atomizer 410 according to an embodiment of the invention. The atomizer 410 is the same as the atomizer 310 shown in Fig. 8 except that the proximal end 302 of the atomizer 410 comprises a peripheral skirt 450 with a recess 452 disposed therein. An interior surface of the skirt 450 comprises a connection means 454, such as an internal thread. This facilitates connection of the atomizer 410 to another element of a burner, such as a fuel and/or atomizing medium input means. One or more washers (not shown), such as copper washers, can be provided within the recess to ensure a secure connection.

Unlike conventional atomizers, the atomizers described above in accordance with embodiments of the invention may need to be manufactured using 3-D printing techniques, such as additive layer manufacturing (ALM). Compared with traditional techniques, ALM allows very precise control of the shapes and dimensions of features of the atomizers, such as the cut-outs between the outlets, the protruding outlets and the non-circular shapes of the inlets and/or outlets. It is these features that allow the atomizers of the invention to have significantly improved performance compared with conventional atomizers. Any suitable material can be used to construct the atomizers. Typically, metals or metal alloys, such as Inconel 718 or cobalt chrome, would be used. The skilled person will understand that any suitable material can equally be used.

As described above, existing atomizers offer a maximum turndown of 15: 1. Atomizers according to the invention have been shown to offer turndowns as high as 42: 1 when diesel oil is used as the fuel, and 23: 1 when HFO is used as the fuel. Therefore, the invention provides a significantly improved turndown over existing atomizers, offering a significant reduction in fuel and operating costs.

In the embodiments described above, the fuel is typically an oil or an oil and gas mixture. For example, the oil may be diesel oil, marine gas oil, gas oil, low sulphur marine gas oil (LSMGO), heavy fuel oil (HFO), ultra low sulphur heavy fuel oil (ULSHFO) or any other liquid fuel.. The atomizing medium is typically steam or compressed gas (e.g. compressed air). However, the skilled person will understand that any suitable fuel and/or atomizing medium could equally be used. The fuel is typically delivered to the atomizer at a pressure ranging from 1.0 Bar.g to 40.0 Bar.g with the atomizing medium delivered as a relationship to fuel oil pressure.

Whilst "Y" jet atomizers have been mentioned specifically above, the principles of the invention described can equally be applied to any other suitable atomizer configuration, such as "F" jet atomizers. This will be understood by the skilled person.

It will be understood that any of the features of the atomizers 1 10, 210 and 310 can be combined with any of the features from any other atomizer described above.

The present invention has been described above in exemplary form with reference to the accompanying drawings which represent specific embodiments of the invention. It will be understood that many different embodiments of the invention exist, and that these embodiments all fall within the scope of the invention as defined by the appended claims.

Claims

An atomizer for a burner comprising:

an atomization region;

a proximal end comprising at least one inlet configured to allow fuel and/or an atomizing medium to enter the atomization region; and

wherein an external surface of the distal end is shaped to permit air flow around at least one outlet.

An atomizer according to claim 1 , wherein the proximal end of the atomizer comprises at least one first inlet configured to allow fuel to enter the atomization region and at least one second inlet configured to allow an atomizing medium to enter the atomization region.

An atomizer according to claim 1 or claim 2, wherein the proximal end of the atomizer comprises a plurality of first inlets.

An atomizer according to claim 2 or claim 3, wherein the proximal end of the atomizer comprises a plurality of second inlets.

An atomizer according to any one of the preceding claims, wherein the distal end of the atomizer comprises a plurality of outlets.

An atomizer according to claim 5, wherein the external surface of the distal end is shaped to permit air flow between the outlets.

An atomizer according to any one of the preceding claims, wherein the at least one outlet protrudes from the external surface of the distal end of the atomizer.

An atomizer according to claim 7, wherein the outlets protrude from the external surface of the distal end of the atomizer at different orientations.

An atomizer according to any one of the preceding claims, comprising a channel, groove, cut, trough or indent between at least one outlet and at least one other outlet to permit air flow between the outlets.

10. An atomizer according to any one of the preceding claims, wherein the at least one outlet comprises a bore or lumen defining an internal cross-section and a tube defining an external cross-section.

1 1. An atomizer according to claim 10, wherein the internal cross-section and/or the external cross- section is non-circular.

12. An atomizer according to claim 10 or claim 1 1 , wherein the internal cross-section and the external cross-section are non-circular.

13. An atomizer according to any one of claims 10 to 12, wherein the internal cross-section is square, rectangular or curved.

14. An atomizer according to any one of claims 10 to 13, wherein the external cross-section is tear- shaped.

15. An atomizer according to any one of the preceding claims, wherein the first inlet(s) are disposed radially outside the second inlet(s).

16. An atomizer according to any one of the preceding claims, wherein the first inlet(s) and the second inlet(s) are configured to direct fuel entering the atomization region through the first inlet and atomizing medium entering the atomization region through the second inlet towards each other to atomize the fuel.

17. An atomizer according to any one of the preceding claims, wherein a proximal end of the atomizer comprises a peripheral skirt with a recess disposed therein.

18. An atomizer according to claim 17, wherein an interior surface of the skirt comprises a connection means, such as an internal thread.

19. An atomizer for a burner comprising:

an atomization region;

a first inlet configured to allow fuel to enter the atomization region;

wherein the first inlet, the second inlet and/or the outlet comprises a bore having a non- circular cross-section.

20. An atomizer according to claim 19, wherein at least two of the first inlet, the second inlet and the outlet comprise a bore having a non-circular cross-section.

21. An atomizer according to claim 19 or claim 20, wherein all of the first inlet, the second inlet and the outlet comprise a bore having a non-circular cross-section.

22. An atomizer according to any one of claims 19 to 21 , wherein the first inlet has a square, rectangular or curved cross-section.

23. An atomizer according to any one of claims 19 to 22, wherein the second inlet has a square, rectangular or curved cross-section.

24. An atomizer according to any one of claims 19 to 23, wherein the outlet has a square, rectangular or curved cross-section.

25. An atomizer according to any one of claims 19 to 24, further comprising a plurality of first inlets.

26. An atomizer according to any one of claims 19 to 25, further comprising a plurality of second inlets.

27. An atomizer according to any one of claims 19 to 26, further comprising a plurality of outlets.

28. An atomizer according to any one of claims 19 to 27, wherein the first inlet(s) are disposed radially outside the second inlet(s).

29. An atomizer according to any one of claims 19 to 28, wherein the first inlet(s) and the second inlet(s) are configured to direct fuel entering the atomization region through the first inlet and atomizing medium entering the atomization region through the second inlet towards each other to atomize the fuel.

30. An atomizer according to any one of claims 19 to 29, wherein a proximal end of the atomizer comprises a peripheral skirt with a recess disposed therein.

31. An atomizer according to claim 30, wherein an interior surface of the skirt comprises a connection means, such as an internal thread.

32. An atomizer according to any one of the previous claims and manufactured using additive layer manufacturing (ALM).

33. An atomizer according to any one of the preceding claims and comprising a metal or a metal alloy.

34. An atomizer according to any one of the preceding claims and comprising Inconel 718 or cobalt chrome.

35. An atomizer according to any one of the preceding claims, wherein the fuel comprises an oil or an oil and gas mixture.

36. An atomizer according to any one of the preceding claims, wherein the fuel comprises diesel oil, marine gas oil, gas oil, low sulphur marine gas oil (LSMGO), heavy fuel oil (HFO), ultra low sulphur heavy fuel oil (ULSHFO) or any other liquid fuel..

37. An atomizer according to any one of the preceding claims, wherein the atomizing medium comprises compressed gas (e.g. compressed air) or steam.

38. A burner comprising:

A combustion zone; and

an atomizer according to any one of the preceding claims,

39. A burner according to claim 38, wherein the combustion zone is a primary combustion zone.

40. A burner according to claim 38 or claim 39, further comprising a combustion stabilising device that creates the combustion zone.

41. A burner according to any one of claims 38 to 40, wherein the burner is a diesel burner or a HFO burner.

42. An atomizer substantially as hereinbefore described and as shown in the accompanying drawings.

43. A burner substantially as hereinbefore described and as shown in the accompanying drawings.