WO2011022846A1

WO2011022846A1 - Oil burner, especially for heavy oil

Info

Publication number: WO2011022846A1
Application number: PCT/CH2009/000286
Authority: WO
Inventors: Philippe Maeder; Matthias Bobst
Original assignee: Ammann Schweiz Ag
Priority date: 2009-08-26
Filing date: 2009-08-26
Publication date: 2011-03-03

Abstract

The invention relates to an oil burner (1) comprising a burner lance (4), by means of which during operation, the oil to be burned is injected, via nozzles extending in a radially outward direction, in a first duct (8) that has an annular cross-section and is penetrated by atomizer air (Z). In the region of its outlet, the first duct (8) is coaxially surrounded by a second annular duct (17), through which combustion air (V) flows during operation and the outlet zone of which is designed such that the atomizer air stream (Z) that is discharged from the first duct (8) and is loaded with injected oil is surrounded by an enveloping flow of combustion air (V) during operation. The oil burner is designed such that the amounts of atomizer air and combustion air flowing through the first duct (8) and the second duct (17) can be separately adjusted.

Description

Oil burners, especially for heavy oil

TECHNICAL AREA

The invention relates to an oil burner, in particular for heavy oil, and a hot gas generator with the oil burner according to the preambles of the independent claims. STATE OF THE ART

The generation of hot gas streams for drying and heating purposes in industry, for example for the drying and heating of granulated mineral material in asphalt production, often enormous amounts of energy are required, with the result that the energy costs make up a significant proportion of the manufacturing cost of the final product , There is therefore a need to use the most cost-effective for such processes energy sources. In addition to the use of waste heat sources, the avail- ability of flammable industrial residues, such as heavy oil, which is a residue in the refinery industry, offers the availability, provided the availability. This is burnt with specially adapted oil burners, in which the heavy oil is injected into a stream of atomizing air and this atomizing air stream carrying the atomised oil is subsequently surrounded by a sheath flow of combustion air. The burner output is controlled by the injected oil quantity and the temperature of the generated hot gas flow by the supplied air volume. To allow adaptation to different conditions of use, some burners also have the option to change the flow cross-section for the atomizing air. Even though the latter burners offer a clear improvement in terms of adaptability to different operating conditions compared to solid geothermal burners. have shown in practice that there is still a need for improvement, since these burners are used not only under a variety of conditions, but are operated with different fuel qualities, and it often happens that the fuel quality varies during operation.

PRESENTATION OF THE INVENTION

It is therefore the object to provide an oil burner and an oil-operated hot gas generator available, which do not have or at least partially avoid the disadvantages of the prior art.

This object is achieved by the oil burner and the hot gas generator according to the independent claims.

According to claim 1, the invention relates in a first aspect to a preferably suitable for heavy oil oil burner. The oil burner has a first flow channel, which is traversed by atomized air during operation and in which, during operation with oil injection means, such as injectors, the oil to be burned is injected and entrained by the Zerstäuberluftströmung, whereby it is atomized and transported into the combustion zone , Furthermore, the oil burner comprises a second flow channel, which is traversed during operation with combustion air in order to supply it to the combustion zone. The burner outlet side or combustion zone side exits of these two flow channels are designed such that during operation of emerging from the outlet of the second flow channel combustion air flow forms an enveloping flow around the emerging from the outlet of the first flow channel and the atomized atomizing Zerstäuberluft- ström around, the Zerstäuberluftstrom circumferential is completely surrounded by the combustion air flow.

In this case, the oil burner is configured such that a separate adjustment of the atomizing air quantity flowing through the first flow channel during operation and the amount of combustion air flowing through the second flow channel is possible, that is, these air volumes are individually, i. via separately operable adjustment, are adjustable. The terms "atomizing air quantity" and "amount of combustion air" are used here and below to denote in each case the amount of air per unit of time, that is to say the volume or mass flow of atomizing air and combustion air passing through the respective flow channel during operation. The separate adjustability of atomizing air quantity and amount of combustion air can be realized by a wide variety of setting members, e.g. by separately adjustable throttle bodies for the atomizer and combustion air provided by a common fan, by two separately controllable fans for the atomizing air and the combustion air and / or by independently adjustable geometries of the flow cross sections for the atomizing air and the combustion air.

In the burners according to the invention, the operating states in the burner itself can be influenced in a wide range by separate regulation or adjustment of the atomizing air quantity, the amount of combustion air and the amount of fuel supplied per unit of time, which results in a significantly improved adaptability with respect to a wide variety of operating conditions compared with the prior art and fuel qualities results.

In a preferred embodiment of the oil burner, the outlet of the first flow channel for the atomized atomizing atomizing air flow has a circular or annular outlet cross-section and the combustion zone-side outlet of the second Flow channel for the combustion air flow to an annular outlet cross-section, which is seen in the flow direction concentric with the outlet cross-section of the first flow channel. By such a design of the outlet geometries, a rotationally symmetrical flow structure can be realized at the burner outlet, which is conducive to a uniform flame pattern and good combustion.

In a further preferred embodiment of the oil burner, the means for oil injection comprise a burner lance with one or more nozzles which, viewed in the flow direction of the atomizer air flow, preferably spray radially outwardly. As a result, a good atomization of the injected oil can be achieved.

In the case of embodiments with burner lances having a plurality of nozzles projecting radially outwards, it is further advantageous that the first flow channel has an annular cross-section in the region of the nozzles, since this results in a particularly uniform distribution of the injected oil in the atomizer air stream emerging from the first flow channel leaves .

Furthermore, it is preferred in embodiments of the inventive burner with burner lances that the flow cross-section of the first flow channel is adjustable in the region of the outlet of the nozzles of the burner lance, preferably during operation of the burner. This makes it possible to influence the flow speed of the atomizing air in the area of the nozzle outlets as well as the pressure loss in the first flow channel for the atomizing air, and thus the atomizing power of the atomizing air and its quantity. It is preferred that the adjustment of the flow cross-section of the first flow channel by axial displacement of the burner lance against an outer boundary of the first flow channel in this Area can be done. This makes it possible to realize a relatively simple and reliable way the setting ^¬ bility of the flow cross section of the flow channel formed between the burner lance and Zerstäuberluftführung.

In still another preferred embodiment, the oil burner to realize the separate adjustability of the atomizing air quantity and the amount of combustion air separately operable throttle for the atomizing air and the combustion air. In this way, the atomizer and combustion air streams, which flow through the first and the second flow channel during operation, can be adjusted individually to the desired air quantities in a simple manner, even if they are generated by a common blower.

In a further preferred embodiment, the oil burner is designed such that an adjustment of the amount of atomizing air, the amount of combustion air or the Zerstäububer- and the combustion air amount during operation of the burner is possible. This makes it possible to adapt the oil burner without interrupting operation to changing operating conditions or fuel qualities. In this case, the setting can be done manually or via actuators of a control, resulting in the latter case, the advantage that the burner can be integrated into a control loop, which allows automatic adjustment of Zerstäububer- and combustion air quantity to the respective operating conditions and fuel qualities.

In yet another preferred embodiment of the inventive oil burner, a swirling device is provided in the first atomizing air flow channel upstream of the region in which the oil to be atomized is injected in operation, which constitutes the atomizing air flow prior to impinging on the injected oil Impose twist. As a result, a uniform distribution of injected oil in the Zerstäuberluftströmung favors.

In yet another preferred embodiment of the oil burner, a swirl device is arranged in the second flow channel for the combustion air upstream of the outlet end thereof, which forces the combustion air flow during operation before exiting from the second flow channel to a twist ^¬ . This ensures that the combustion air emerging from this flow channel during operation forms a spiral enveloping flow around the atomizer air flow that is discharged from the first flow channel and atomizes the oil. This in turn favors the formation of a stable, rotationally symmetric combustion zone and complete combustion of the injected oil.

The aforementioned swirl devices are preferably designed as a swirl body with a plurality of swirl vanes or as helical vanes. Such swirl devices have proven to be expedient and reliable in the field of oil burners.

In yet another preferred embodiment, the oil burner also has a third flow channel, which is flowed through with additional air during operation, for supplying additional air to the combustion zone. The outlet region of this flow channel for the additional air is designed in such a way that the combustion air stream exiting from the second flow channel as the sheath flow is surrounded by additional air flowing out of the third flow channel. As a result, further air can be supplied to the outer region of the combustion zone, which further promotes complete combustion. In addition, the additional air can simultaneously serve the cooling of external burner components.

The outlet of the third flow channel advantageously has an annular shape. Cross-section, which is seen in the flow direction concentric with the outlet cross-sections of the first flow channel and the second flow channel. This makes it possible to realize a rotationally symmetrical flow structure at the burner outlet, which is conducive to a uniform flame pattern and good combustion.

Furthermore, in the last-mentioned embodiment of the oil burner with a third flow channel for additional air guidance, it is preferred for the oil burner to have injectors and to be designed in such a way that in the

Operation with the injectors by expansion of air, which is taken from the guided in the burner atomizer air flow or combustion air flow, sucked fresh air and fed together with the expanded air as additional air to the third flow channel. As a result, the additional air can be provided in an economical manner during operation.

If the oil burner is designed in such a way that the injectors are supplied during operation with a subset of the adjustable amount of combustion air, which is preferred, then a coupling between combustion air quantity and additional air quantity results such that an increase in the quantity of combustion air also leads to an increase in the additional air quantity leads and vice versa.

In yet another preferred embodiment, the oil burner comprises a single-stage blower which serves to provide both the atomizing air and the combustion air. Such oil burners are inexpensive and robust.

According to claim 15, a second aspect of the invention relates to a hot gas generator with a

Combustion chamber, which forms a combustion chamber into which an oil burner according to the first aspect of the invention opens, such that the combustion chamber surrounds the combustion zone during operation. In such use of the invented burner according to the invention for a hot gas generator, the advantages of the invention are particularly evident.

In a preferred embodiment of the

Hot gas generator has this a plurality of preferably identical oil burner according to the first aspect of the invention, which open into the combustion chamber, wherein it is further preferred that they open at identical axial positions with respect to the flow direction of the hot gas generated in operation with the hot gas generator in the furnace. In this way, hot gas generators according to the invention having virtually any heating power can be provided with a burner size.

BRIEF DESCRIPTION OF THE DRAWINGS

Further embodiments, advantages and applications of the invention will become apparent from the dependent claims and from the following description with reference to FIGS. Showing:

1 is a perspective top view obliquely from above of a heavy oil burner according to the invention;

FIG. 2 shows a vertical section through the heavy oil burner from FIG. 1; FIG. and

3 shows a perspective sectional view through the burner arrangement of the burner from FIGS. 1 and 2.

WAYS FOR CARRYING OUT THE INVENTION

A preferred embodiment of the inventive oil burner in the form of a heavy oil burner 1 is shown in FIGS. 1 and 2, once in a perspective plan view and once in a vertical section. As can be seen, the oil burner basically consists of a single-stage radial fan 2 for providing the atomizing and combustion air and a burner assembly 3, which are screwed together. The fan 2 provides compressed air during operation with an overpressure of about 100 to 150 mbar for Ver ^¬ addition.

As can be seen from Fig. 2 in conjunction with Fig. 3, which shows the burner assembly 3 in perspective in section, located in the center of the burner assembly 3, a burner lance 4, at the burner outlet side or brennennungszonenseitigem end of a nozzle body 5 with radial outwardly extending nozzle bores (not shown) which form claims nozzles, is arranged. At its other end, the burner lance 4 is connected to a supply line 20 for heavy oil. Within the burner lance 4, a central bore is present, which connects the supply line 20 with the nozzle bores.

The burner lance 4 is coaxially surrounded by a first tube 6, which in the region of the outlet of the nozzle bores from the nozzle body 5 has an insert 7, which tapers the tube cross section in this area to a venturi. Between the tube 6 with the end arranged in this insert 7 and the burner lance 4 with the associated nozzle body 5, a first, annular flow channel 8 is formed (demanding first flow channel), which in the region of the outlet of the nozzle holes from the nozzle body 5 its smallest flow cross-section has and via a separately operable first throttle valve 9 with the outlet side of the blower 2 is connectable.

Upstream of the nozzle body 5 in the first flow channel 8 is a spiral baffle 10, which imparts a twist to the atomizing air Z flowing through the flow channel 8 during its operation into the region of the flow channel 8 bounded by the insert 7. The baffle 10 is supported by the burner lance 4 and is firmly connected thereto.

The burner lance 4 is held at the "cold" end of the burner assembly 3 in a releasable clamping device 11 and can after releasing this Klemmvorrich- tion 11 are axially displaced within the first tube 6. This makes it possible, formed between the insert 7 and the nozzle body 5 in the region of the outlet of the nozzle bores smallest cross-section of the first flow channel 8 by axial displacement of the

Adjust nozzle body 5 in the venturi formed by the insert 7.

The first tube 6 is coaxially surrounded by a second tube 12, which in turn is coaxially surrounded by a third tube 16, which has a nozzle-like insert 19 in the region of its burner outlet end. The insert 19 tapers the tube cross-section in this area towards the burner outlet-side end first suddenly and then steadily increasing. Between the second tube 12 with the nozzle ring 14 and the third tube 16 with the insert 19, a second, annular flow channel 17 is formed for combustion air (demanding second flow channel). This second flow channel 17 can be connected via a separately operable second throttle valve 18 with the outlet side of the blower 2.

The insert 19 surrounds the first tube 6 with the insert 7 arranged therein in the region of the outlet-side end of the insert 7 and delimits the second flow channel 17 for the combustion air V formed in this region between it and the nozzle ring 14 in such a way that Operation emerging from the second flow channel 17 combustion air V forms a sheath flow around the emerging from the insert 7 and thus from the first flow channel 8 and atomized atomized atomizing air flow Z around.

The third tube 16 is coaxially surrounded by a fourth tube 21. Between the third tube 16 and the fourth tube 21, a third annular flow channel 22 for additional air L is formed (demanding third flow channel). The fourth tube 21 surrounds the third tube 16 in the region of the outlet-side end the same so that in the operation of the third

Flow channel 22 exiting additional air L forms a sheath flow to the emerging from the third tube 16 and thus from the second flow channel 17 combustion air flow V.

As can be seen further, the third is

Flow channel 22 for the additional air L via injector tubes 23 connected to a space 25 which is bounded by the second throttle valve 18 for the combustion air V. In the area of the injector tubes 23, the fourth tube 21 has suction openings 24 which connect the third flow channel 22 surrounded by the latter and the outlet sides of the injector tubes 23 to the environment.

In operation, the burner lance 4 is fed via a fuel pump (not shown) to heavy oil with an overpressure of 2 to 3 bar, which is then injected via the nozzle bores of the nozzle body 5 into the first flow channel 8.

At the same time, atomizing air Z from the blower 2 is supplied to the first flow channel 8 via the first throttle flap 9 and a first collecting space 26, and combustion air V from the blower 2 is supplied to the second flow channel 17 via the second throttle flap 18 and a second plenum 25.

The atomizing air Z flowing in the first flow channel 8 passes through the region in which the spiral guide plate 10 is arranged, and then enters the region in which the heavy oil is injected via the nozzle bores of the nozzle body 5 into the first flow channel 8 as swirling flow , It tears the injected heavy oil with it and then exits as atomizing air flow Z with finely dispersed heavy oil particles from the insert 7 of the first tube 6, in order then to be burned in the combustion zone.

The guided in the second flow channel 17

Combustion air V occurs in the area of the exit side End of this flow channel 17 in a swirl body 27 arranged there, which it leaves as a swirl flow. Subsequently, it enters the nozzle-shaped insert 19, which forms the outlet-side end of the second flow channel 17. The latter then leaves it as a spirally rotating flow which forms an envelope flow of combustion air V around the atomizer air stream Z exiting from the insert 7 and thus out of the first flow channel 8 with the atomized heavy oil contained therein.

A subset of the combustion air quantity V entering the second plenum 25 via the second throttle valve 18 is expanded via the injector tubes 23 into the third flow channel 22. At the same time 24 fresh air from the environment is sucked into the third flow channel 22 by the injector generated thereby via the intake openings 24, which then mixed with the air expanded through the injectors 23 and continues as claim-compliant additional air L in the third flow channel 23. At the end of this flow channel 23, the additional air flow Z passes through an arrangement of guide ribs 28 before it emerges therefrom, thereby forming a straightened envelope flow around the spiral envelope flow of combustion air V emerging from the second flow channel 17.

Alternatively or in addition to the heavy oil firing, the burner 1 can also be operated with a fuel gas. As can be seen, a further annular flow channel 13 is formed between the first tube 6 and the second tube 12, which opens into a nozzle ring 14 on the burner outlet side and is connected at its other end to a fuel gas feed line 15. Fuel gas can be conducted from the fuel gas feed 15 to the nozzle ring 14 via this further flow channel 13, for injecting the fuel gas into the combustion zone. During operation of the burner, the throttle valves 9, 18 can be adjusted individually in such a way that a desired flame pattern is obtained, optionally with additional adjustment of the axial position of the burner lance 4 and the amount of fuel supplied. If an operation with fuel gas takes place, the supplied fuel gas amount can be adjusted.

While preferred embodiments of the invention are described in the present application, it should be clearly understood that the invention is not limited to these and may be practiced otherwise within the scope of the following claims.

Claims

1. oil burner (1), in particular for heavy oil, comprising

a) a first flow channel (8), which is permeable during operation with atomizing air (Z);

b) a second flow channel (17) which can be flowed through during operation with combustion air (V); and

c) means for oil injection (4, 5), with which the oil to be burned in the first flow channel can be injected during operation, for atomizing the same with atomizing air,

wherein the two flow channels (8, 17) have outlets which are designed in such a way that, during operation, the combustion air flow (V) exiting from the outlet of the second flow channel (17) generates an enveloping flow around the outlet from the outlet of the first flow channel (8). exiting and atomizing oil carrying atomizing air stream (Z) around,

and wherein the oil burner (1) has separately operable adjusting members (9, 18) for the atomizing air (Z) and the combustion air (V), for enabling a separate adjustability of the atomizing air quantity flowing through the first flow passage (8) during operation and in FIG Operation of the second flow channel (17) flowing through the amount of combustion air.

2. Oil burner (1) according to claim 1, wherein the outlet of the first flow channel (8) has a circular or annular outlet cross section and the outlet of the second flow channel (17) has an annular outlet cross-section, which seen in the flow direction concentric with the outlet cross-section of the first flow channel ( 8).

3. Oil burner (1) according to one of the preceding

Claims, wherein the oil injection means comprises a burner Nerlanze (4, 5) with one or more, in particular radially outwardly spray nozzles.

4. Oil burner (1) according to claim 3 with a burner lance (4, 5) with a plurality of radially outwardly spray nozzles, wherein the first flow channel (8) in the region of the nozzles has an annular cross-section.

5. Oil burner (1) according to one of claims 3 to 4, wherein the oil burner (1) is designed such that the flow cross-section of the first flow channel (8) in the region of the outlet of the nozzle of the burner lance

(4, 5) is adjustable, in particular by axial displacement of the burner lance (4, 5) relative to an outer boundary of the first flow channel (8) in this area.

6. Oil burner (1) according to one of the preceding

Claims, wherein the burner (1) as separately operable adjusting members for the atomizing air (Z) and the combustion air (V) separately operable throttle valves (9, 18).

7. Oil burner (1) according to one of the preceding

Claims, wherein the burner (1) is designed such that the adjustment of the amount of atomizing air and / or the amount of combustion air during operation of the burner (1) is possible.

8. Oil burner (1) according to one of the preceding

Claims, wherein in the first flow channel (8) upstream of the region in which oil to be atomized in operation with the oil injection means (4, 5) is injected into this, a swirl device (10) is arranged, in particular a swirl body more

Swirl vanes or a spiral baffle (10) which impart a twist to the atomizer air flow (Z) during operation prior to impinging on the injected oil.

9. Oil burner (1) according to one of the preceding

Claims, wherein in the second flow channel (17) one upstream of its exit end

Swirl device is arranged, in particular a swirl body with a plurality of swirl vanes (27) or a spiral guide plate, which forces the combustion air flow (V) during operation before exiting from this flow channel (17) a twist.

10. Oil burner (1) according to one of the preceding claims, further comprising a third flow channel (22), which is permeable during operation with additional air (L), said flow channel (22) having a discharge, which is designed such the secondary air flow (Z) emerging from its outlet during operation forms an envelope flow around the combustion air flow (V) emerging from the second flow channel (8).

11. Oil burner (1) according to claim 10, wherein the

Outlet of the third flow channel (22) has an annular outlet cross section, which is seen in the flow direction concentric with the outlet cross sections of the first flow channel (8) and the second flow channel (17).

12. Oil burner (1) according to any one of claims 10 to 11, wherein the oil burner (1) injectors (23) and is designed such that in operation with the injectors (23) by expansion of air which in the burner (1 ) is taken out, fresh air is sucked in and fed together with the expanded air as additional air (L) the third flow channel (22).

13. Oil burner (1) according to claim 12, wherein the

Burner (1) is designed such that the injectors (23) can be fed during operation with a subset of the adjustable amount of combustion air.

14. Oil burner (1) according to one of the preceding claims, wherein the burner (1) is a single-stage bubble (2) for providing the atomizing air (Z) and the combustion air (V).

15. hot gas generator with a combustion chamber which forms a combustion chamber into which an oil burner (1) opens according to one of claims 1 to 14.

16. hot gas generator according to claim 15, wherein a plurality of particular identical oil burner (1) according to one of claims 1 to 14 open into the combustion chamber, in particular at identical axial positions with respect to the flow direction of the hot gas generated during operation with the hot gas generator.