EP2126471B1 - Hollow flame - Google Patents

Description

State of the art

The invention relates to a method according to the preamble of claim 1, or a burner device in particular for carrying out this method according to the preamble of claim 13.

An increasing problem with such furnaces consists in the relatively large heat requirement and thereby to be observed limit values of the toxic component in the exhaust gas. Here, especially the pollution of the environment NO _{x plays} a major role, its share is known to increase with increasing temperature of the combustion process (namely the flame).

A second not insignificant problem is the increasing fuel prices in the implementation of potential energy present in the fuel into heat and their transition to the heat transfer medium, such as water, in a heating system, of course, with the least possible effort a favorable related efficiency is sought.

As is known, direct convection of a hot flame on the boiler wall is particularly favorable for heat transfer to the heat transfer material. However, such a particularly hot flame generates a lot of NO _x in the exhaust gas. Of course, the radiation of a flame is also important for the heat transfer, but less important than its convection effect. In addition, the heat transfer depends on a number of other factors, such. B. absorption and reflection through the boiler wall.

This problem of heat transfer relates to the shape and design of the flame in the furnace and is so far regardless of the nature of the fuel to see whether it is, for example, a combustion of liquid or gaseous fuels.

In a known method and a blower burner in particular for carrying out this method ( WO 2007/134580 Dreizler) liquid and / or gaseous fuels are burned with combustion air downstream of a burner tube and a baffle plate in a downstream combustion chamber, this combustion chamber may be formed, for example through the wall of a boiler, to obtain the known advantages of the prior art here. In addition, individual flames are formed in this method and blower burner by spaced from each other and to the burner tube axis individual flames, which give a Hüllflamme, which is controlled by controlling the combustion air in quantity and shape according to the need also the performance of the flames. An essential feature of combustion modeling of this combustion, however, is that in the center of the individual nozzles or individual flames, for example a central one Gas nozzle, a core flame is formed within the envelope flame, which causes an internal exhaust gas recirculation with the individual flames of the envelope flame, and wherein by changing the ratio of the fuel supply to the envelope flame or the nuclear flame modeling of at least the core flame is possible. As a result of this modeling, NO _x -reducing internal recirculation of exhaust gas in the region of the core flame is controlled. Regardless of this, the core flame can serve as a pilot or pilot flame and also serve to change the performance.

In another known method or a burner device ( EP 0 347 834 , Dreizler and EP 0 857 915 , Elco) is a central fuel nozzle is present, the continuous operation of the Nachzündmöglichkeit the other nozzles to cause a safe combustion process in the other nozzles. In addition, there are flow resistances in the combustion chamber, which are intended to effect a recirculation of exhaust gas in the outer flame region, whereby a reduction in the combustion temperature is expected with the resulting decrease in NO _x , without therefore the important also for the heat transfer radiation temperature of the flame goes back. Each of the individual flames has in tearing off the flame formed centrally an extraordinary importance for the current reignition of the fuel-air mixture, which is important for a good efficiency. Returned exhaust gases are not supplied to the interior of a Hüllflamme here to achieve the desired NO _x decontamination.

In a known generic burner device ( DE 40 02 238 A1 Elco) takes place only downstream of the baffle plate and a burner tube in a combustion chamber combustion, with spaced nozzles in the plane of the baffle plate, which are arranged in a circle, wherein a total of one homogeneous mixing of the injected fuel should take place and the blue-flame flame should have lower core temperatures, thereby reducing the proportion of nitrogen oxides. Apart from the additional arrangements of a complex combustion chamber in a burner tube downstream of the baffle plate in order to achieve this desired homogeneous mixing, in this known burner, a diameter ratio of the distance of a quarter of the diameter of the burner tube to the longitudinal axis of the same. As a result, no recirculation of exhaust gas can form in the center of the flame, ie around the longitudinal axis purely functional, which is why this is done via a centrally located exhaust gas supply pipe in the baffle plate, so an external and separate exhaust gas recirculation takes place and, the exhaust gas of the flame on the exhaust side removed and fed via a separate blower to the center of the flame. Such a device is not only very expensive but also a security risk. To delineate the prior art, there is alternatively described a solution without exhaust gas recirculation, in which a stoichiometric combustion is achieved by targeted metering of the combustion air, a certainly very difficult task.

In yet another known gas burner system ( US 1,976,097 ), the fuel gas is introduced via three closely juxtaposed largely centrally located nozzles, for which corresponding openings are provided in a baffle plate and wherein the combustion takes place in a burner tube downstream of a larger diameter combustion chamber and the combustion air is controlled by a throttle valve. A genus-related feature is not present here.

In the case of another plant serving only for oil firing ( EP 0 913 631 A2 Weishaupt) is, as in the prior art described above, centrally disposed an atomizer nozzle with a surrounding flame tube and with around the central atomizer around the flame tube to the atomization space facing number of additional atomizer nozzles, which are evenly spaced. This is intended, on the one hand, to achieve a homogeneous distribution of fuel air with the exhaust gas recirculated here, and, on the other hand, to achieve a NO _x reduction. Details of the envelope flame and a centrally arranged core flame are insofar known by the above-mentioned prior art.

In another known burner device ( DE 691 28 333 T2 out EP 0 478 305 B1 , Hitachi), which serves primarily as a premix burner for gas turbines, are arranged centrally symmetrical gas nozzles and a flow resistance is arranged in the mixture stream of combustion air and fuel gas in the flame, thereby to recirculate "combustion gas substantially downstream of the center of the eddy current" , Basically, they are free-flames, which are formed by external nozzles that ride on a central flame. Although this cooling of the center of the flame and thus a reduction of the NO _x -Anteils is achieved, but without the help of recirculating exhaust gas and at the cost of a great effort regarding. Design and arrangement of this centrally arranged in the flame flow resistance. In addition, this arranged in the flame flow resistance must be heat resistant accordingly. Not least because of the flow dynamics at and around the flow resistance, there are considerable doubts about the flame stability of this burner device.

A problem completely independent of the reduction of the NO _x content in the exhaust gas is the special combustion of special substances such as regenerative substances or additives which either do not burn on their own or cause a reduction of the toxic constituent in the exhaust gas during combustion. For example, urea feed causes a reduction in the NO _x content, or the glycerol produced in the production of biodiesel can be detoxified by a chemical conversion by afterburning. Among the hard-to-dispose substances include, among others, heavy oils, frying fat udgl. The disposal of these substances by combustion is known to take place in very complex processes and devices.

The considered state of the art assumes that an enveloping flame formed by individual flames requires a central fuel injection with a nuclear flame, also in conjunction with an exhaust gas recirculation. This was always accompanied by the problem of mixing material flows with the additives / special fuels in the atomization phase and with the constant risk of incomplete combustion and poison emission in the exhaust gas, which could only be countered with high air excess and inefficiency.

The problem underlying the invention

The invention has for its object a method, or to develop a burner device for carrying out this method, with or with the cooling of individual flames and the resulting total flame is given with a total reduction of NO _x values, and this without a device arranged in the flame for Control of a flame kernel. This should also be possible to easily change or modulate the given burner performance on the fuel side without detriment to a detoxification of the exhaust gases. In addition, the invention is also based on the object of achieving a simplified solution for the special combustion of, in particular, non-combustible substances on their own, without a significant deterioration of the exhaust gas therefore occurring.

The invention and its advantages

The inventive method or the burner device according to the invention with the characterizing features of claims 1 and 13 has the advantage over the known methods and burner devices that the recirculation of exhaust gases takes place in the interior of the overall flame, whereby the desired NOx detoxification is achieved in the desired extent and that the usual in the prior art central flame, or core flame is omitted and instead the individual flames form a Hüllflamme with an internally hollow stable overall flame with, for example, cup-shaped cross-section, in the cavity of the Abfasrezirkulation takes place. The invention not only increases the efficiency, but also achieves technical safety and a substantial reduction in the manufacturing and operating costs.

To control the combustion air, this is at least partially directed to the center of the total flame, wherein through the baffle plate a congestion or a negative pressure in the cavity of the overall flame is formed, so that this flame has an internal, taking place within the cavity recirculation of exhaust gases. This recirculation Within the overall flame is additionally promoted by the provided in the center of the baffle plate opening for the combustion air.

Such an overall flame open towards the airflow has a central exhaust gas recirculation, with no combustion occurring due to the central orifice plate opening within the cavity of the flame. The arrangement according to the invention makes it easy to change the heat output via the flames and nevertheless there is a central (internal) recirculation of exhaust gas which is important for the detoxification (NOx) of the flames or flame.

According to an advantageous embodiment of the invention, the individual flames or nozzles consist of base flames or basic nozzles and auxiliary flames or auxiliary nozzles, of which the base flames of the ignition and control of combustion are used. The basic flame, for example, located further outwards, is assigned an additional flame which is controlled and ignited by the base flame, the final flame formed from the base flame and also in combination with the additional flame forming the overall flame. To achieve this, according to the invention a corresponding control of the combustion air is required, namely in the form of a baffle plate with a central opening, so that formed in the interior of this due to the arranged in the air flow baffle plate and in connection with the distance from the center of the individual nozzles (individual flames) It is particularly advantageous in this case that the additional flame of the base flame can be superimposed with a corresponding increase in power or can be switched off, without therefore the exhaust gas detoxifying criteria, such as the internal recirculation of exhaust, to be deteriorated. While in the overall flame the recirculation of the exhaust gases automatically changes with the size of the flame, the recirculation on the outside of the overall flame can be done anyway by the means known in the art.

This can still support the direct combustion of the overall flame in the combustion chamber by the arrangement of the individual nozzles directly on a plane with the outlet opening between the cone and baffle plate. Now, both from the inside and from the outside, the exhaust gases recirculating can cool and detoxify the basic flame consisting of single flames, as well as the total flame supplemented with an additional flame in the entire power range.

An additional advantage is that a firing device with a basic nozzle and additional nozzle is particularly inexpensive to produce and, above all, is easy to control. This advantage relates above all to the possibility of arranging such a firing device within the tubular firing head, besides nozzles for a liquid fuel, such as light fuel oil, nozzles for a gaseous fuel, such as natural gas.

Advantageously, the base flames or the basic nozzles are rather more outside, so from the center of the combustion area farther away, arranged, a Grundflame can control several additional flames. Thus, in an embodiment of the invention, the nozzles of the individual flames, ie of base flames and additional flame, also be arranged side by side on a circle, with the advantage that the cavity of the overall flame formed mainly by the additional flames is low and causes a uniform internal recirculation regardless of whether only the base flame or the additional flames are in operation.

Preferably, the individual flames, for example, base flame or additional flame, also be alternatively in operation. So z. B. a 3-stage performance can be achieved. In this case, the first stage could be achieved by the base flame, the second alternatively by the additional flame and the third stage by the addition of the base flame and additional flame.

According to an advantageous embodiment of the invention, the control of the flames via the control of the reflux of the fuel in a return of the same can take place. It is particularly advantageous that the power of the flame on the given by the nozzles Rückströmmenge is controlled so that a stepless control is possible.

While in the flame the recirculation of the exhaust gases changes automatically with the size of the flame, the recirculation on the outside of the flame is anyway controlled by means known in the art.

Thus, according to an advantageous embodiment of the invention, a recirculation of exhaust gas on the outside of the flame is achieved by arranged in the air flow means. Such a recirculation of the exhaust gases through webs projecting into the combustion air flow is known ( EP 0 347 834 B1 , Dreizler). Hereby it is achieved that the flames on the outside are cooled due to the exhaust gas recirculation in order to achieve a reduction of the NOx, without, therefore, real power losses occur in the convection between the flame and the heat carrier. This embodiment of the invention is a combination of the outer recirculation with the total flame or with the recirculation of exhaust gas in the center of the individual flames, regardless of whether the total flame according to the invention forms a total of a cavity. Depending on the control of the total flame formed from individual flames, background flames and additional flames, this has in its central hollow-shaped area by the recirculation taking place there a relatively low temperature, but with little, there already ineffective or unnecessary, radiation intensity. The fuel energy is thus converted primarily to the outer region of this hollow overall flame and transferred to the heat transfer material, for example, water next to a boiler wall, optionally with the interposition of a flame tube.

According to an additional advantageous claimed for itself embodiment of the invention, apart from the possibility of controlling the individual flames or of the base flame and additional flame, and each supplied amount of fuel can be controlled. However, such a quantity control can also be performed on one of the types of flames (individual flame, Basic flame, additional flame), when using different fuels in the claimed burner device by one of these different fuels, which then happens in the supply lines to the respective other nozzles and control means. As a device for controlling the fuel lines, an electrically actuated valve or an electrically operated slide can be used according to the invention. In this way, the firing capacity can be controlled in a known manner even with special fuel. However, it can also be arranged for control of the amount of fuel supplied in at least one of the fuel lines, a quantity control valve, in addition to a merely the supply of fuel releasing or blocking device.

According to one embodiment of the invention, the respective flames or nozzles may be provided with their own ignition devices, as in contrast to the known firing device, a central ignition and control device is missing. Although such individual equipment would result in additional expense, they would be more favorable in terms of overall equipment than a central control flame, especially as regards fuel consumption, which is also increasing in importance due to increasing prices.

According to an additional embodiment of the burner device, the fuel lines branch off to the individual nozzles as well as to the basic nozzles and / or additional nozzles of a respective central line connected to the fuel source, in each of which a control device for the quantity control of the fuel is arranged. In this way, the desired connection, disconnection or alternative switching of the fuel to the nozzles can be carried out in a simple manner. Again, it should be noted that it may be different fuels, for example, that the base flame is that of an oil burner, whereas the additional flame is formed by a gas flame.

In particular, when it comes to the same fuel, according to an additional embodiment of the invention, the lines leading to the base nozzle and auxiliary nozzle lines are preceded by a main line which connects these lines with each other and is controllably supplied with fuel.

According to an additional advantageous embodiment of the invention, the base nozzle and the additional nozzle are arranged coaxially with each other in the individual nozzles, for example, as a central Ölbrennerdüse within a coaxially arranged around these gas nozzle. As a result, the remaining passage cross-section determined by the nozzles is not unnecessarily restricted in the burner tube for the combustion air. One can thus accommodate and apply this method structurally well even with smaller burner heads.

After an additional, also working without a core flame embodiment of the invention takes place in the inventive method or the burner device according to the invention within the overall flame a special combustion not suitable for the intrinsic flame generation suitable special substances by these are conducted into the existing cavity there, through Using a special special nozzle, which is arranged centrally to the cavity forming the cavity within the overall flame. On the one hand, these special substances are additives which detoxify the main fuel by catalytic reaction in the overall flame or combustible liquid or gaseous waste materials, which can now economically be economically supplied for energy utilization and utilization. It is thus not a nuclear flame as in the prior art.

According to this embodiment of the invention, the combustion method according to the invention and the burner device are advantageously supplemented by the use of an additive atomization, wherein the additives are advantageously fed to the center of the overall flame, which in particular via a centrally introduced, hydraulically controlled lance. For example, the additive effect of the exhaust gas detoxification can take place along the entire space forming the overall flame, without adversely affecting the combustion process.

Description of the embodiments

Several embodiments of the invention are illustrated in the drawings and will be described in more detail below.

It shows very simplified:

Fig. 1

a longitudinal section with function symbols;

Fig. 2

a view from the front side of the oil burner device Fig. 1 ;

Fig. 3

a hydraulic circuit diagram for an oil burner device;

Fig. 4

a hydraulic circuit diagram for a Ölbrennereinrichtung with basic and auxiliary nozzle;

Fig. 5

frontal view of an oil burner to Fig. 4 with arrangement of the nozzles on a circle;

Fig. 6

Longitudinal section with function symbols with arrangement of the nozzle pairs radially to each other;

Fig. 7

Longitudinal section with functional symbols for a gas burner device;

Fig. 8

Longitudinal section and front view of a combination burner for oil and gas;

Fig. 9

front view for a combination burner with two parallel oil burner nozzles;

Fig. 10

Longitudinal section through a combination burner with coaxial arrangement of oil and gas nozzle;

Fig. 11

a hydraulic circuit diagram for an oil burner, combined with a nozzle for special combustion;

Fig. 12

the front view of the oil burner with special combustion after Fig. 11 ;

Fig. 13

a hydraulic circuit diagram for a Ölbrennereinrichtung with basic and auxiliary nozzle and two nozzles for special combustion;

Fig. 14

an end view of the oil burner with special combustion after Fig. 13 ;

Fig. 15

Longitudinal section through an externally controlled lance.

In Fig. 1 and Fig. 2 is an oil burner in longitudinal section and shown from the front side, in which in a burner tube 1 oil nozzles 2 are arranged in a circle around a baffle plate 3, which has a central opening 4. The burner tube 1 has on its end facing the baffle plate 3 an inwardly directed cone 5, which forms an annular passage opening 6 with the outer edge of the baffle plate 3. The fuel oil passes from a tank 7 via a line 8 by means of a pump 9 to the Oil nozzles 2, wherein in the line 8 to the control of a solenoid valve 10 is arranged. For distribution to the individual oil nozzles 2, a branch 11 to individual lines 12 is provided in the line 8.

The combustion air is introduced by known means, not shown, such as a radial fan on the back 13 of the burner tube 1, in this in the flow direction 14 as soon as the furnace is in operation. This air flow impinges on the baffle plate 3 and is guided via the circular passage opening 6 and the central opening 4 into a combustion chamber 15. About the solenoid valve 10, the oil flow to the oil nozzles 2 is delayed transmitted and atomized after exiting the nozzle 2 and ignited. This creates individual flames 16.1 and 16.2. In the baffle plate also radially extending swirl blades 17 are provided, through which the combustion air is swirled on exiting the burner tube 1 into the combustion chamber 15 in order to achieve a good mixing with the fuel atomized via the oil nozzles 2. In addition, recirculation 18 of exhaust gas on the outside to the total flame 16.3 formed by the individual flames 16.1 and 16.2 is achieved by the cone 5 on the burner tube 1.

At the foot of the total flame 16.3 formed by the individual flames 16.1 and .2 and downstream of the central opening 4 of the baffle plate 3, according to the invention, a cavity 19 is formed which is open towards the central opening 4 and open away from the same through the total flame 16.3 as far as the flame end can and causes a central flame-free zone, which prevails in this cavity 19 due to the congestion effect of lack of combustion air, or lack of oxygen. Due to this stowage effect, in particular the design of the central opening 4, it is achieved that within the cavity 19 a Recirculation of exhaust gas takes place, with the result of detoxification of the NO _x share during the combustion process. The high internal CO content is then burned downstream completely in the combustion chamber 15 free of pollutants. The very low temperatures in the central area of the total flame 16.3 lead to the fact that no harmful NO _x content can form at all.

At the in Fig. 3 shown hydraulic circuit diagram for an oil burner with four each individual flames 16.1 and .2 generating oil nozzles 2 are arranged on the nozzle sticks 20 under pressure-opening control heads 21, which open into a common pressurized control line 23. This control line 23 comes from the pressure side of the pump 9 and serves to supply the individual nozzles 2. The control heads 21 open via a spring-actuated auxiliary cylinder, the needle valves 43 (FIGS. Fig. 15 ) effective only from a defined pressure in the supply line 22 from the control line 23 forth to the nozzles, and allow for pressure drop the automatic nozzle closure, which prevents leakage of the fuel at a standstill. From the control heads 21 is in each case a return line 12, which opens into a return manifold 8 with downstream pressure control part 26 for the power regulation. In the return line 8 additional control valves 10 may be arranged, which operate independently of the quantity control. This advantageous arrangement makes it possible to regulate the atomization pressure at the nozzles 2 steplessly via the pressure control part 26. As mentioned above, the control over the return line in the invention is particularly advantageous.

At the in Fig. 4 and Fig. 5 illustrated embodiment is an oil burner, in each of which closely adjacent to each other and on a circle two oil nozzles 27 and 28 are arranged in pairs, the individual flames 16.1 and 16.2 produce and of which a nozzle 27 serves as a basic nozzle, while the adjacent second nozzle 28 is provided as an additional nozzle, wherein the base nozzle 16.1 and the auxiliary nozzle generates an additional flame 16.2. The basic flames and additional flames cause the overall flame 16.3, wherein for the adjustment or tuning of the individual nozzles to each other, the passage through the individual lines 12 can be adjusted. Basically, the oil lines are formed as in the previous examples, namely with a line 8, in which a solenoid valve 10 is arranged, which leads to a branch 11, from which the individual lines 12 branch off, leading to the oil nozzles. The oil supply takes place via a pump 9 to a manifold 29, from which the two lines 8 lead to the branches 11.

The working pressure in the distributor 29 ( Fig. 4 ) is controlled by two pressure meters 30. According to the invention, a single nozzle can be provided in each case instead of this double nozzle arrangement, in which the flow, as in this embodiment but also the embodiment according to Fig. 1 , is shown. But it can also be controlled by the return of one or both of these total flame 16.3 forming the base nozzle or auxiliary nozzle. The particular advantage of the double nozzle arrangement is that one of the nozzles operates continuously, so that its flame, the base flame 16.1 or additional flame 16.2, controls the other flames. In this way it is ensured that a multi-level regulation of the total flame 16.3 can be switched smoothly in a simple way to burner power regulation. In addition, advantageously a modeling of the flame can take place.

This in Fig. 6 illustrated embodiment has as in Fig. 1 a burner tube 1, however, regardless of the type of Fuel pairs and radially to each other arranged nozzles 31 and 32, the supply lines 33 and 34 are controlled according to the different nature of the fuel via a respective valve 35 and 36. Again, the cavity 19 is mainly formed by the central opening 4 and between the individual flames 16.1 and 16.2, and the total flame 16.3, which are generated via the nozzles 32. The flames, which are generated via the nozzles 31, are basic flame 16.1, the addition of which connect the nozzles 32 with additional flames 16.2 in the sum of the total flame 16.3 form a hollow flame.

In Fig. 7 a gas burner is shown simplified in longitudinal section, the principle in the construction of the example Fig. 1 corresponds with the difference that four gas nozzles 37 are used instead of four oil burner nozzles. The gas flow in the supply line 38 is controlled by a gas slide 39. Again, according to the invention forms with the help of the baffle plate 3, the cavity 19 within the 16.4 formed from the individual flames 16.1 Gesamtflamme.

At the in Fig. 8 illustrated embodiment is shown in two partial sections and an end view of the burner tube end of a combined oil / gas burner, arranged in which arranged on a circle according to the example Fig. 2 four oil burner nozzles are provided and according to the embodiment according to Fig. 7 however, eight additional gas burner nozzles 37 are provided. In this case, the total flame 16.3 can be formed via the nozzles 2 and / or via the nozzles 37. The advantages of using oil and / or gas as fuel are particularly present given the scarcity of fuels.

In Fig. 9 is exemplified over the frontal view of an oil / gas burner, as similar to the embodiment according to Fig. 5 Oil nozzles are arranged in pairs and turn according to the embodiment according to Fig. 8 are combined with gas nozzles 37, wherein each nozzle are arranged on a circle.

In the embodiment according to Fig. 10 it is also an oil / gas burner, in which, however, the oil lines 41 and the gas lines 42 are arranged in sections coaxially, so that the oil nozzles 2 and the gas nozzles 37 are arranged in a known manner with the known advantages coaxially to each other ( WO 2007/134580 A1 ; Fig. 4 ).

In Fig. 11 and 13 The hydraulic supplementary plans for the control of heavy or non-combustible special fuels are shown, which correspond in combination with the hydraulic circuit diagrams 3 and 4 are used and according to which additives are introduced into the cavity of the overall flame via a spray nozzle 40. The function is congruent with the control of the fuels 3 or 4 and realized with identical or similar components.

Fig. 12 and 14 show the supplementary arrangement of heavy or non-combustible special fuels or additives and their Einleitungsgeometrie on the atomizer nozzle 40 to the same basic arrangements according to Fig. 2 and Fig. 5 nozzles for training of the total flame.

Fig. 15 shows the basic design of the hydraulic control of the control head 21. The control heads 21 open via a spring-actuated auxiliary cylinder 25 from a defined pressure in the supply line 22. Only the needle valves 43 allow for pressure drop The automatic nozzle closure, which prevents fuel leakage at standstill.

LIST OF REFERENCE NUMBERS

1

burner tube

2

oil jets

3

baffle plate

4

centr. opening

5

cone

6

Through opening

7

tank

8th

management

9

pump

10

magnetic valve

11

diversion

12

Return line

13

back

14

Flow direction air

15

combustion chamber

16.1

basic flame

16.2

additional flame

16.3

total flame

17

swirl blades

18

recirculation

19

cavity

20

nozzle

21

control head

22

supply

23

control line

24

magnetic valve

25

auxiliary cylinder

26

Pressure control part

27

Oil base nozzle

28

Oil additive nozzle

29

distributor

30

pressure meters

31

Radial nozzles

32

Additional nozzles radially

33

supply line

34

supply line

35

Valve

36

Valve

37

gas nozzles

38

supply

39

gas slide

40

Special fuel / additive nozzle

41

oil line

42

gas pipe

43

needle valve

Claims (25)

1. A method of burning liquid and/or gaseous fuels using combustion air in a combustion chamber (15) disposed downstream of a combustion tube and downstream of a baffle plate (3)

   - using a plurality of individual flames (16.1, 16.2) formed by fuel supplied via a number of individual nozzles (2, 27, 28, 31, 32, and 37) spaced apart from one another and from the axis of the combustion tube,

   - using a combined flame (16.3) formed by the individual flames (16.1 and 16.2), and

   - using means for controlling the combustion air amount and/or flow shape depending on the requirements of the method,

   - the combined flame (16.3) being formed without a central core flame, i.e. without a central fuel nozzle,

   - the individual flames (16.1 and 16.2) being spaced apart from the centre of the combined flame (16.3) and disposed at a given distance from one another, such that the combined flame (16.3), which is thus formed without a core flame, has a corresponding void (19) formed downstream of the baffle plate, and

   - the combustion air control including that said combustion air is at least partially directed towards the centre of the combined flame (16.3) and that the baffle plate (3) is used to create a bottleneck or negative pressure within the void (19) of the combined flame (16.3), such that an internal recirculation of burned gases takes place within the void (19),
   characterised in that

   - such recirculation is enhanced by a central opening (4) in the baffle plate (3), said opening formed in the baffle plate (3) being arranged centrally with respect to the airflow and to the individual nozzles (2, 27, 28, 31, 32, and 37).
2. The method as claimed in claim 1, characterised in that said individual flames consist of base flames (16.1) and additional flames (16.2), said base flames (16.1) serving for the ignition and control of the additional flames (16.2) and, therefore, of the combined flame (16.3).
3. The method as claimed in any one of claims 1 or 2, characterised in that the performance of at least some flames is regulated by controlling the fuel return flow.
4. The method as claimed in any of the preceding claims, characterised in that a multi-stage operating performance is achieved by supplying the fuel via at least three individual nozzles (2, 27, 28, 31, 32, and 37) which may be activated and/or deactivated independently from one another.
5. The method as claimed in any of the preceding claims, characterised in that the amount of fuel supplied to at least one of the individual nozzles (2, 27, 28, 31, 32, and 37) may be varied.
6. The method as claimed in claim 5, characterised in that such variation in amount may include reducing the fuel flow to zero.
7. The method as claimed in any of the preceding claims, characterised in that at least one of the individual flames (16.1, 16.2) (the base flame and/or the additional flame) has its own ignition device.
8. The method as claimed in any of the preceding claims, characterised in that means (3, 5) are arranged in the combustion air flow towards the outer periphery of the combined flame (16.3) so as to permit a recirculation (18) of burned gas to take place also on the outer side of the flames.
9. The method as claimed in any of the preceding claims, characterised in that through the introduction of flame-retardant and/or inflammable substances (oils, additives, urea, or the like) into the void (19) of the combined flame (16.3), a separate combustion, or detoxification reaction, of separate substances that are not supposed to contribute to the flame production will take place.
10. The method as claimed in claim 9, characterised in that the substances intended to undergo the separate combustion process are directed into the centre of the void (19) of the combined flame (16.3).
11. The method as claimed in claim 9 or 10, characterised in that said separate combustion process is based on the utilisation of substances (glycerine, lean fuel gases etc.) which are not per se independently flammable or apt for participating in the flame production.
12. The method as claimed in any one of claims 9 to 11, characterised in that additives (urea, steam, or the like) are used for the purpose of flame detoxification.
13. A burner device to be fuelled with oil and/or gas having individual nozzles for merging individual flames (16.1 and 16.2) into a combined flame (16.3), in particular for performing the method as claimed in any one of claims 1 to 12,

    - with a central fuel nozzle having been omitted, such that the combined flame, which is formed without a core flame, has a void (19) formed therein,

    - having a flame tube (1) that in the flow direction (14) is open towards the flame,

    - having individual nozzles (2, 27, 28, 31, 32, and 37) for injecting, evaporating, and introducing the fuel, with the flame tube (1) having a cone (5) formed at the end thereof and the individual nozzles (2, 27, 28, 31, 32, and 37) being arranged within said flame tube and said cone (5) at a given distance from one another and from the centre of the flame tube (1),

    - having fuel lines (8, 12, 22, 23, 38, 41, 42) leading to the individual nozzles (2, 27, 28, 31, 32, and 37),

    - having control devices (10, 24, 35, 26, 35, 36, 39) arranged within said fuel lines (8, 12, 22, 23, 38, 41, 42) for controlling the fuel,

    - having an air fan device serving for supplying the combustion air, and

    - having a flow control means (3) which is present in the flow of combustion air and realised in the form of a baffle plate, characterised in that said baffle plate (3) has a central opening (4) disposed centrally with respect to both the air flow and the individual nozzles (2, 27, 28, 31, 32, and 37) such that a negative pressure created downstream thereof in the central region of the combined flame will form the flameless void (19) within which an internal recirculation of burned gases take place.
14. The burner device as claimed in claim 13, characterised in that a common tubular flame tube (1) shared between the fuel nozzles (2, 27, 28, 31, 32, and 37) is provided upstream of the flame zone and that in this common flame tube (1) beside the individual nozzles (2, 27, 28, 31, 32, and 37) serving as base nozzles, a plurality of additional nozzles (2, 27, 28, 31, 32, and 37) are provided and disposed at a distance from one another and at a distance from the central axis of the flame tube (1).
15. The burner device as claimed in any one of claims 13 to 14, characterised in that the control device is realised as an electrically operated valve or slide (10, 24, 35, 26, 35, 36, 39) arranged in at least one of the fuel lines (8, 12, 22, 23, 38, 41, 42).
16. The burner device as claimed in claim 15, characterised in that for controlling the amount of fuel supplied to the nozzles, a quantity control valve (10) is arranged in at least one of the fuel lines (8, 11, 12).
17. The burner device as claimed in any one of claims 13 to 16, characterised in that apart from the fuel supply line (22, 23) at least one of the fuel nozzles has a fuel return line (8, 12) within which a control device (26) for a fuel return flow amount is arranged.
18. The burner device as claimed in any one of claims 14 to 17, characterised in that disregarding the type of fuel used, the various different nozzles (individual nozzle, base nozzle, additional nozzle 2, 27, 28, 31, 32, and 37) are disposed side by side on at least one circle the centre of which is largely situated in the centre of the baffle plate (3).
19. The burner device as claimed in any one of claims 14 to 18, characterised in that the fuel lines (8, 12, 22, 23, 38, 41, 42) leading to the base nozzles (27, 31) and/or the additional nozzles (28, 32) are respectively branched from one central line connected to the fuel source and independently controllable and in that within each of the branch lines a fuel quantity control device (35, 36, 10) is arranged.
20. The burner device as claimed in any one of claims 14 to 19, characterised in that a combined arrangement of oil nozzles (2, 27, 28) and gas nozzles (31, 32, 37) is provided, with either of the base nozzle and the additional nozzle functioning as an oil nozzle and/or a gas nozzle.
21. The burner device as claimed in claim 20, characterised in that the oil nozzle (2) is respectively arranged coaxially within the gas nozzle (37).
22. The burner device as claimed in any one of claims 13 to 21, characterised in that within the flame tube (1) a separate nozzle (40) is centrally arranged with respect to the nozzles (2, 27, 28, 31, 32, and 37) forming the combined flame and is used for the purpose of introducing nonflammable additives or of separately burning certain special, flame-retardant combustibles.
23. The burner device as claimed in claim 22, characterised in that the separate nozzle (40) has a lance protruding into the hollow region of the flame for introducing the nonflammables into the combined flame permitting the burned gases to be recirculated.
24. The burner device as claimed in any one of claims 22 and 23, characterised in that the separate nozzle (40) has a flow line and a return line for the nonflammables.
25. The burner device as claimed in claim 24, characterised in that the separate nozzle (40) is hydraulically operated.

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