Burner for combusting fuel comprising solid hydrocarbons

Abstract

 The invention relates to a burner for combusting fuel comprising solid hydrocarbons, comprising at least an outer tube (17) and an inner tube (20)arranged in the outer tube, wherein a first space (R1) is formed between the outer tube and the inner tube and a second space (R2) is formed in the inner tube, wherein a first combustion chamber (V1) intended for pre-combustion of the fuel is formed in the first space and the second space is intended for transporting gas products produced during the pre-combustion to a second combustion chamber (V2) which is connectable to the inner tube and is intended for the purpose of post-combustion of the gas products, and wherein the burner is provided with fuel supply means (21) connected to an opening (25) in the outer tube, the first space is provided with fuel transport means (12), such as for instance a screw, for transporting through the first combustion chamber the fuel supplied by the fuel supply means, the burner is provided with one or more ignition elements (15) for igniting the fuel present in the first combustion chamber, the outer tube is provided with first air supply means (L1) for supplying air under overpressure into the first combustion chamber, the outer tube is provided with a discharge for discharging the combustion residues produced during the combustion of the fuel, the inner tube is provided substantially close to the first combustion chamber with first openings, the inner tube is provided with second air supply means (L2) for supplying air under overpressure into the second space such that during operation the gas products are carried out of the first combustion chamber through the openings to the second space.

Description

[0001] The device relates to a burner for combusting fuel comprising solid hydrocarbons, comprising at least an outer tube and an inner tube arranged in the outer tube, wherein a first space is formed between the outer tube and the inner tube and a second space is formed in the inner tube, wherein a first combustion chamber intended for pre-combustion of the fuel is formed in the first space and the second space is intended for transporting gas products produced during the pre-combustion to a second combustion chamber which is connectable to the inner tube and is intended for the purpose of post-combustion of the gas products, and wherein the burner is provided with fuel supply means connected to an opening in the outer tube, the first space is provided with fuel transport means, such as for instance a screw, for transporting through the first combustion chamber the fuel supplied by the fuel supply means, the burner is provided with one or more ignition elements for igniting the fuel present in the first combustion chamber, the outer tube is provided with first air supply means for supplying air under overpressure into the first combustion chamber, the outer tube is provided with a discharge for discharging the combustion residues produced during the combustion of the fuel, the inner tube is provided substantially close to the first combustion chamber with first openings, the inner tube is provided with second air supply means for supplying air under overpressure into the second space such that during operation the gas products are carried out of the first combustion chamber through the openings to the second space.

[0002] A burner according to the preamble is known in the field and is described in the Netherlands patent NL8700945.

[0003] The known burner has the drawback that the first combustion chamber is located in the part in which the fuel transport means are also arranged. This has the great drawback that the fuel transport means are also heated. The temperature in the first combustion chamber can rise to 600°C to 700°C, whereby high standards have to be set for the fuel transport means. In addition, the first combustion chamber is situated a distance from the second combustion chamber so that the known burner is relatively large in longitudinal direction. The known burner cannot hereby be applied as replacement for a pre-burner of oil or gas-fired compact installations such as for instance a CH boiler.

[0004] It is the object of the invention to provide a burner according to the preamble which does not have the above stated drawbacks.

[0005] The burner according to the invention has for this purpose the feature that the first combustion chamber is situated close to the connection of the second combustion chamber and the fuel transport means are arranged outside the first combustion chamber. The burner according to the invention hereby has a more compact form and the part of the burner where the fuel transport means are located is not heated during operation. In addition, both the first and the second combustion chamber are situated inside the installation, such as a CH boiler or steam boiler, where the burner is installed. All heat created hereby ends up in the boiler, which results in a higher efficiency.

[0006] The first combustion chamber is preferably situated adjacently of the connection of the second combustion chamber.

[0007] In a preferred embodiment of the burner according to the invention both the outer tube and the inner tube consist of a first part which is connected fixedly to the burner and a second part which is connected releasably to the burner, and the first combustion chamber is formed by the second parts of the outer tube and the inner tube. The first combustion chamber is subject to wear because of the great heat. A worn combustion chamber can be easily replaced in this embodiment. In addition, it is possible to make the combustion chamber from a different material than the rest of the burner, for instance ceramic material.

[0008] In an elegant preferred embodiment of the burner according to the invention the burner is provided with an air chamber connectable to an air supply device, such as for instance a fan, and the first air supply means are connected to the air chamber by means of a first air regulator and the second air supply means by means of a second air regulator. Only one air supply device is therefore necessary. In the known burner a minimum of two air supply devices are necessary.

[0009] In a preferred embodiment of the burner according to the invention the air chamber is arranged in the line of the outer tube, the air chamber is separated from the first space by means of a flange, a part of the inner tube is situated in the air chamber, the inner tube passes through the flange by means of a first passage in the flange and an outer end of the inner tube is bearing-mounted in the air chamber. The burner according to the invention can hereby remain compact in transverse direction, while the length of the burner hardly increases.

[0010] The first air regulator preferably comprises at least one second passage in the flange, which second passage connects the first air supply means to the air chamber and a controllable first valve for closing the at least one second passage. In this inventive manner the burner is provided with a first air regulator which can be realized in economically advantageous manner. The first valve is preferably formed here by a disc which lies against the flange and is rotatably connected to the flange, and the disc comprises passages co-acting with the second passages in the flange.

[0011] The second air regulator preferably comprises at least one second opening in the part of the inner tube situated in the air chamber, which second opening connects the second air supply means to the air chamber, and comprises a controllable second valve for closing the at least one second opening. In this inventive manner the burner is provided with a second air regulator which can be realized in economically advantageous manner. The second valve comprises here at least one tubular ring which is arranged round the inner tube and is slidable in controllable manner in the longitudinal direction of the inner tube, and which is intended for closing the second opening.

[0012] The burner is preferably configured for mounting by means of a mounting flange on a boiler such that the first and second combustion chambers are situated in the boiler. The part of the outer tube 17 which is mounted in the boiler preferably takes a conical form here.

[0013] The invention will be further elucidated with reference to the following figures, in which:

Figure 1 shows a cross-section in longitudinal direction of a preferred embodiment of the burner according to the invention.

Figure 2 shows a view of the end plate of the burner according to Figure 1.

[0014] Figure 1 shows a cross-section in longitudinal direction of a preferred embodiment of the burner B according to the invention. The burner B is configured to combust fuel F comprising solid hydrocarbons, such as for instance wood, sawdust, wood pellets, rice husks, grass, pods, peelings, nuts and palm oil kernels. The fuel F preferably consists of biomass.

[0015] The burner B comprises an outer burner casing formed by an outer tube 17 and a part 19 of inner tube 20 arranged in outer tube 17, which part 19 is provided with perforations or openings. A first space R1 is formed between outer tube 17 and inner tube 20 and a second space R2 is formed in inner tube 20. Both outer tube 17 and inner tube 20 consist of a first part, in the direction of D1, which is connected fixedly to the burner, and a second part, in the direction of D2, which is connected releasably to the burner B by means of a mounting flange 16. Mounting flange 16 also provides a fixing option for the purpose of fixing the burner B to a boiler. The releasable second part of inner tube 20 is preferably disposed in stationary manner.

[0016] Outer tube 17 is provided with a discharge in end plate 18 for the purpose of discharging the combustion residues produced during the combustion of the fuel F.

[0017] In the first space R1 the second parts of outer tube 17 and inner tube 20 form a first combustion chamber V1 intended for pre-combustion of the fuel F. The first combustion chamber V1 is adjacent to the connection of the second combustion chamber V2. Outer tube 17 is provided with first air supply means L1 formed by the perforated primary air pipe 19 and the primary air chamber 13 for the purpose of supplying air under overpressure into the first combustion chamber V1.

[0018] The second space R2 is intended for transporting gas products G produced during the pre-combustion to a second combustion chamber V2 which is connectable to inner tube 20 and intended for the purpose of post-combustion of the gas products G. The burner B is provided with fuel supply means 21 which are connected to an opening 25 in the part of outer tube 17 comprising first space R1.

[0019] The first space R1 is provided with fuel transport means 12, for instance a screw or screw conveyor, for transporting through the first combustion chamber V1 the fuel F supplied by the fuel supply means 21. The fuel transport means 12 are arranged outside the first combustion chamber V1.

[0020] The burner B is preferably provided with one or more ignition elements 15 for igniting the fuel F present in the first combustion chamber V1.

[0021] Inner tube 20 is provided substantially close to the first combustion chamber V1 with first openings 26 and provided with second air supply means L2 for supplying air under overpressure into the second space R2 such that during operation the gas products G are carried out of the first combustion chamber V1 through openings 26 to the second space R2 and subsequently guided to the second combustion chamber V2.

[0022] The burner B is provided with an air chamber 24 which is connectable to an air supply device 5, such as for instance a fan. Air chamber 24 lies in the line of outer tube 17 and is separated by means of a flange 8 from the first space R1. A part 27 of inner tube 20 is situated in air chamber 24, wherein inner tube 20 passes through flange 8 by means of a first passage 28 in flange 8. An outer end of inner tube 20 is bearing-mounted in air chamber 24 by means of bearing 4 accommodated in bearing housing 3.

[0023] The first air supply means L1 are connected to air chamber 24 by means of a first air regulator, formed by a controllable valve comprising air disc 7 provided with passages 30 and second passages 29 in flange 8.

[0024] The second air supply means L2 are connected to air chamber 24 by means of a second air regulator formed by an air slide valve 10 consisting of a tubular ring and at least one air gap 11. Air slide valve 10 can be operated by means of pinion 1 which displaces air slide valve 10 via gear rack 2.

[0025] An optimal material feed to the material chamber R1 is realized by means of a material detection sensor 14. Optimal combustion is realized by controlling primary air disc 7 and secondary air slide valve 10. Capacity control takes place by means of controlling material screw 12. The first air regulator and the second air regulator can be controlled such that optimum combustion of the fuel F takes place.

[0026] Material screw 12 is driven by means of drive shaft screw 22, whereby fuel F is displaced from the material section space R1 to the combustion section space R2. Pipes 17, 19 and 20 are fixed and form the burner head.

[0027] Figure 2 shows a view of end plate 18 of the burner according to Figure 1. The end plate is provided with three annular openings 31, 32 and 33. Annular openings 31 and 32 form the ash outlet for the ash which is created in the first combustion chamber V1. Annular opening 33 is intended for connection to the second combustion chamber V2.

[0028] It is possible for combustion chamber V2 to extend at least partially in the second space R2.

[0029] The invention is expressly not limited to the shown embodiment. The protection sought extends to any embodiment falling within the claims stated hereinbelow.

Claims

1. Burner for combusting fuel comprising solid hydrocarbons, comprising at least an outer tube and an inner tube arranged in the outer tube, wherein a first space is formed between the outer tube and the inner tube and a second space is formed in the inner tube, wherein a first combustion chamber intended for pre-combustion of the fuel is formed in the first space and the second space is intended for transporting gas products produced during the pre-combustion to a second combustion chamber which is connectable to the inner tube and is intended for the purpose of post-combustion of the gas products, and wherein the burner is provided with fuel supply means connected to an opening in the outer tube, the first space is provided with fuel transport means, such as for instance a screw, for transporting through the first combustion chamber the fuel supplied by the fuel supply means, the burner is provided with one or more ignition elements for igniting the fuel present in the first combustion chamber, the outer tube is provided with first air supply means for supplying air under overpressure into the first combustion chamber, the outer tube is provided with a discharge for discharging the combustion residues produced during the combustion of the fuel, the inner tube is provided substantially close to the first combustion chamber with first openings, the inner tube is provided with second air supply means for supplying air under overpressure into the second space such that during operation the gas products are carried out of the first combustion chamber through the openings to the second space, characterized in that the first combustion chamber is situated close to the connection of the second combustion chamber and the fuel transport means are arranged outside the first combustion chamber.

2. Burner as claimed in claim 1, characterized in that the first combustion chamber is situated adjacently of the connection of the second combustion chamber.

3. Burner as claimed in claim 1 or 2, characterized in that both the outer tube and the inner tube consist of a first part which is connected fixedly to the burner and a second part which is connected releasably to the burner, and wherein the first combustion chamber is formed by the second parts of the outer tube and the inner tube.

4. Burner as claimed in claim 1 or 2, characterized in that the burner is provided with an air chamber connectable to an air supply device, such as for instance a fan, and wherein the first air supply means are connected to the air chamber by means of a first air regulator and the second air supply means by means of a second air regulator.

5. Burner as claimed in claim 3, characterized in that the air chamber is arranged in the line of the outer tube, the air chamber is separated from the first space by means of a flange, a part of the inner tube is situated in the air chamber, wherein the inner tube passes through the flange by means of a first passage in the flange and an outer end of the inner tube is bearing-mounted in the air chamber.

6. Burner as claimed in claim 4, characterized in that the first air regulator comprises at least one second passage in the flange, which second passage connects the first air supply means to the air chamber and a controllable first valve for closing the at least one second passage.

7. Burner as claimed in claim 5, characterized in that the first valve is formed by a disc which lies against the flange and is rotatably connected to the flange, and wherein the disc comprises passages co-acting with the second passages in the flange.

8. Burner as claimed in claim 4, 5 or 6, characterized in that the second air regulator comprises at least one second opening in the part of the inner tube situated in the air chamber, which second opening connects the second air supply means to the air chamber, and comprises a controllable second valve for closing the at least one second opening.

9. Burner as claimed in claim 7, characterized in that the second valve comprises at least one tubular ring which is arranged round the inner tube and is slidable in controllable manner in the longitudinal direction of the inner tube, and which is intended for closing the second opening.

10. Burner as claimed in any of the foregoing claims, wherein the burner is configured for mounting by means of a mounting flange on a boiler such that the first and second combustion chambers are situated in the boiler.

Drawing