US20160161117A1

US20160161117A1 - Method for operating a multi-burner system by means of combustion air pressure measurement and regulation

Info

Publication number: US20160161117A1
Application number: US14/907,286
Authority: US
Inventors: Markus Webel
Original assignee: EE EMISSION ENGINEERING GmbH
Current assignee: EE EMISSION ENGINEERING GmbH
Priority date: 2013-08-01
Filing date: 2014-07-28
Publication date: 2016-06-09
Also published as: DE102013012943A1; WO2015014477A1; DE102013012943B4

Abstract

The invention relates to a method for operating a multiple burner system (32), which comprises a number of burner groups, whereby each burner group have at least one air duct (3,8) assigned, via which air is supplied to a burner group, whereby each burner group has at least one k^thair channel (4,6) by which the supplied air splits up into a k^thair, whereby for each k^thair channel (4,6) of all burner groups an air pressure value for the k^thair is measured, whereby all measured air pressure values for the k^thair are compared with one another, whereby it is checked if air pressure values for the k^thair of the burner groups differ from one another, whereby deviating air pressure values of the k^thair inside the k^thair channels (4,6) are modified.

Description

TECHNICAL FIELD

The invention relates to a method and a setup for the operation of a multiple burner system, which is part of a furnace.

BACKGROUND

A combustion chamber of a furnace can comprise of multiple burners, which feed air to the combustion chamber, which is burnt in the chamber in combination with a fuel. Each burner can thereby, due to its geometry and/or construction, be designed to have several air channels, with air supplied via each channel. To ensure that the fuel is burnt efficiently in the combustion chamber, the amount of air supplied must be dosed correctly.
In many furnaces, specifically in those found in oil refineries, it is normally not possible to achieve an air distribution with uniform and appropriate fuel-to-air ratio for each burner or burner group. The reason is that, due to cost constraints, there are almost always no air flow measurements for individual burners, except maybe for large steam boilers. If anything, only the total amount of combustion air to a furnace or respectively to all burners combined is measured. Furthermore, there are normally no automatically adjustable air supply modules or automatic controls for the individual burners or burner groups.
Spot measurements, e.g. with a pitot tube, are possible, but too time-consuming and therefore not economical in practice, as the effort for such measurements at furnaces with many burners, e.g. 70 at a minimum, is considerable.
Against this background, a method and setup with the attributes of independent patent claims are introduced. Details of the invention can be derived from the dependent patent claims and this description.

SUMMARY

The invention relates to a method for the operation of a multiple burner system, comprising a number of burner groups, each consisting of at least one burner. Air is supplied to each burner group throughout at least one associated air duct. Each burner group has at least one k^thair channel, which splits the air, supplied from the air supply duct, into a k^thair and k^thfraction of air, respectively. With the proposed method, the air pressure of the k^thair and the k^thfraction of air, respectively, is measured for the k^thair channel of each burner group. All measured air pressure values for the k^thair of each burner group are then compared with one another, whereby it is checked, whether the values for the k^thair of all burner groups are deviating from one another. Deviating values of the measured air pressures of the k^thair in the k^thair channel of all burner groups will be modified and potentially equalised and/or adjusted.
As part of the configuration of the method, all measured values of the k^thair are usually collected and compared in a central location.
Depending on the definition, the multiple burner system, to which the method will be applied, comprises a number of burner groups, whereby each burner group consists of at least one burner. At least one burner of each burner group is thereby associated with at least one air duct, which feeds air to at least one burner of the burner group. Each burner also has a k^thair channel, which splits the air into a k^thair, whereby for each k^thair channel of all burners the air pressure value of the k^thair is measured, whereby all measured air pressure values of the k^thair of the burners are compared with one another, whereby it is checked, if the air pressure values of the k^thair differs from one another, whereby differing air pressure values of the k^thair inside the k^thair channel will be modified and equalized.
One or more air supply duct is allocated to at least one burner group and/or burner. Each burner group and/or each burner comprises of at least one air channel, namely the k^thair channel. Therefore e.g. for each burner of a burner group, that is to say each m^thburner, at least one air channel, that is to say the k^thair channel, splits off air, that is supplied from the air duct, namely into a k^thair and therefore the air into at least a k^thfraction, whereby normally it splits off in several fractions. Generally every burner group and/or every burner comprises of an air supply duct connection, through which the k^thair channel is connected with the air duct. Due to the geometry of the burner group and/or the burner respectively the air routing inside the burner group casing and/or the burner casing, the supplied air splits up throughout the k^thair channel into a k^thair respectively a k^thfraction.
It can be envisaged, that every burner splits up air, that is supplied from the air duct, throughout a number of air channels into a corresponding number of air fractions, e.g. primary air as a first air, secondary air as second air and tertiary air as a third air and therefore into a possible k^thair.
The method envisages that all air fractions, that are supplied to all burners, are controlled and therefore driven and/or regulated, which also includes, that all air pressure values of the k^thair are compared with one another. Thereby only values for the air pressures for a k^thair respectively the k^thfraction of the supplied air, meaning primary, secondary or tertiary air are compared to one another and are if needed be adjusted. Like this the values for the k^thair respectively the k^thfractions of the supplied air are compared with one another and if needed to be adjusted. Like this the values for the multiple burner system are equalized for each air fraction and therefore each k^thair. After this kind of adjustments respectively balancing the values for various air fractions can still be deviating to one another.
With the help of gathering all measured values for the air pressures at one central location and with the proposed pressure measuring setup, the k^thair of each burner or burner group can be registered and monitored as well as modified with the help of the air modules, whereby a favorable fuel-to-air ratio on all burners or burner groups can be achieved.
Due to the construction of a burner group and/or a burner it is possible to separate the air into fractions, without a need for several air ducts. With the method normally only those fractions of the k^thair in the k^thchannel are considered, that have a common or separate air supply duct.
If the nominal value, if applicable, has a deviating value compared to the actual value of an air pressure in the k^thair channel of a m^thburner, the value can be modified by changing the cross-section of the k^thair channel. This, to be modified value for the air pressure of the k^thair within the k^thair channel for a m^thburner, respectively, is done by adjusting at least one air supply module within the k^thair channel, that can be built e.g. in form of an air damper and can be changed and/or balanced.
In one version of the method it is envisaged, that the air pressure of the k^thair in the k^thair channel has an actual value P_actand the cross-section of the k^thair channel a value A_act. For the cross-section of the k^thair channel, for which the air pressure should be modified, will be adjusted to a nominal value A_nom., whereby the air pressure of the k^thair in the k^thair channel will be adjusted to a nominal value P_nom. Consideration is given to the relationship between the envisaged ratios of the pressure values, namely between the nominal value P_nomand the actual value P_act., and the square of the envisaged ratios of the cross-section values, namely the nominal value A_nom.and the actual value A_act., such that P_nom./P_act.is proportional to (A_act./A_nom.)². According to this, the ratio of the nominal pressure value and the actual pressure value is inversely proportional to the square of the ratio of the actual value and the nominal value of the cross-section. As an alternative or additionally it can be considered, that the ratio P_nom./P_act.is proportional to (V_nom./V_act.)². Thereby V is a volumetric flow rate of air through an air duct. According to this, V_nom.is a nominal value and V_act.an actual value for the volumetric flow rate.
Due to the law of energy conservation respectively the Bernoulli law, in flow cross-section contractions, e.g. inside a pipe or air duct, there is a quadratic correlation between the flow rate and the pressure drop across that contraction, whereby P_nom./P_act.˜(V_nom./V_act.)²applies. This correlation, on which many flow measurement device, e.g. orifice plates, venture nozzles etc. are based on, is used with the proposed method in order to derive the air flow rate by measuring the air pressure inside a burner.
On the air side, a burner can in this context be considered simplistically as an orifice plate, even though the burner does not have the round cross-section of an orifice plate, but a cross-section of potentially rather complex geometry. The cross-section contraction inside a burner occurs in terms of fluid dynamics between the air supply module and the combustion chamber, there were the burner tile is located. Whilst having the air supply module fully open normally approx. 90% of the total air side pressure drop of a burner should be caused there. One reason for this is, that than air has the maximum exit velocity, for mixing the air and the fuel, which is also introduced in this area to the furnace, most efficiently.
With the measurement of the static pressure at the already mentioned position of the k^thair channel by inserting probes, the pressure drop between the air pressure in the k^thair channel and ambient conditions can be measured. The pressure inside the k^thair channel can also be measured against the pressure inside the firebox, which can be measured by another probe located accordingly. As the burners are adjusted in comparison to the measured pressures and/or air flow rates, both alternatives are applicable.
In this embodiment, the air pressure of entire burner groups can be measured, where each burner group consists of one or more burners. In the same manner, the smallest cross-section in the vicinity of the burner tile should be chosen, whereby the cross-section of several burners can be combined into a burner group.
With the adjustments of the air supply modules it is achieved, that the air flow in flow direction is changed in such way, that the pressure drop through that part of the burner, that is just downstream of the air supply module, is changed due to the changed air flow and measured by measuring the static air pressure.
For the correlation between the pressure and the cross-section applies p_nom./p_act.=f*(A_act./A_nom.)², whereby f is a factor of proportionality. Provided that P_nom.=α*P_act., it applies that the cross-section is A_nom.=β*A_act., whereby α and β are factors of proportionality. Here applies, according to above formulas, that α=(f/β²). Accordingly the cross-section of the k^thair channel is to be changed by the factor β=(f/α)^0.5, if the air pressure of the k^thair is to be changed by the factor a.
In a possible embodiment of the method it is envisaged that for a multiple burner system the pressure for the k^thfraction of the air in the first k^thair channel of the first burner group or burner has an actual value of P_act.0=p,0.
In the k^thair channel of a first next burner group or of a first next burner the pressure of the k^thair shows on the other hand an actual value P_{act. 1}<P_act.0, that is by the factor α1 smaller, whereby α1*P _act.1=P_nom.0=P, ₀. In that case the cross-section of the k^thair channel in the first next burner group respectively the first next burner is to be enlarged from an actual value A_act.1by a factor β₁=(f/α1)^0.5to A_nom.1=(f/α₁)^0.5*A_act.1. Furthermore the pressure of the k^thair fraction in a second next burner group respectively in a second next burner shows an actual value P_act2=α₂*P_act0=α₂* P_nom.10, whereby this actual value P_act.2is by the factor a₂larger than the foreseen nominal value P_nom10. In that case the cross-section in the k^thair channel of the second next burner group respectively the second next burner is to be reduced from an actual value A_act2by a factor β₂=(f/α₂)^0.5to the nominal value A_nom2=(f/α₂)^0.5*A_act2.
However, it is also possible to use other measures to equalize the air pressure values of the k^thair in the k^thair channels of the burners.
The inventive setup shows at least one air pressure measurement device in order to measure the air pressure values for the k^thair and if applicable control unit to compare, modify and balance eventually deviating values of the air pressure inside the k^thair channels. As an alternative the adjustment of the air modules for the balancing of the air pressures can be done also manually.
At least one air measurement device is located centrally and designed to simultaneously measure all air pressure values for the k^thair of all burner groups and/or burners.
The setup comprising besides at least one air supply module, that is located inside the minimum one k^thair channel, also a number of probes respectively measuring probes, that are installed in order to measure air pressures in measuring locations, whereby along the k^thair channel of one burner group and/or one burner at least one of such a probe is located, with which it is connected to at least one measuring device by means of e.g. an air hose.
The control unit is designed to modify the cross-section of a k^thair channel by controlling an air supply module, which is located inside this k^thair channel, typically by means of changing the opening position of that air supply module.
For a multiple burner system of a furnace, comprising at least two burners, the inventive method as well as the inventive setup allows the adjustment of an evenly distributed air flow by measuring the static air pressure in at least one location of the multiple burner system as well as the collection of the measured static pressure values with the help of the pressure measuring device in one location.
The measurement of the static pressure can be done as a pressure drop measurement between the measuring probe of the k^thair channel and ambient or as an alternative between a measuring probe of the k^thair channel and the combustion chamber of the furnace.
While applying the invention it is envisaged to collect the pressure values of the k^thair centrally in at least one location, while all k^thfractions of the supplied air of all burner groups and/or burner are simultaneously captured respectively be transmitted allowing the air flow rates indirectly to be read off and/or compared to other burner groups and/or burners of the multi burner system. Based on that, the adjustment of air dampers, whereby each burner group and/or each burner comprising at least one air k^thair channel with one air damper, for all burner groups and/or burners, same air flow rates are assigned, as long as the heat release is the same, whereby the effects of changing the different air dampers opening positions can be centrally determined, compared and/or to be red off. If the heat release of individual burners or burner groups are deviating from one another, the values for the air pressure of those burners respectively burner groups can be determined by using the quadratic correlation between pressure drop and cross-section respectively the flow rate in the respective air channel in order to accomplish the correct air supply.
At least one burner of the multiple burner system, for which the inventive method is envisaged, can be designed as a so called diffusion burner. A diffusion burner mixes and finally ignites the fuel and air (combustion air) only in the area of the flame root. As an alternative and additionally at least one burner can be designed as a premix or at least partially premix burner, for which the combustion air is already mixed with the fuel, before it is physically reaching the flame root.
In industrial furnaces with a two burner or a multiple burner system the combustion air is normally conveyed to the burners with the help of one or more fans, exceptionally also with compressors, for example with a pressure that is above 100 mbar, that inspires air from the environment sending the air throughout a branched distribution system comprising pipes and/or ducts to each individual burner. Thereby an air supply duct is normally connected with at least one, a k^thair channel, respectively. The air pressure in the distribution system is normally low, for example less than 20 mbar. The low air pressure and the circumstance, that the distribution system, due to his asymmetric geometry of the air ducts and therefore different pressure drops and flow profiles, as well as due to eventually built in instruments, for example a check valve and/or throttling devices, leads to unintentional deviating air flows to individual burners. For an ideal combustion the fuel-to-air ratio for each burners must have the same value, therefore the distribution of air to all burners must be adjusted.
As the burners of a two burner or multiple burner system normally are fed with the same amount of fuel, that is to say the same heat release, all burners should receive the same amount of air and as a consequence should have the same fuel-to-air ratio. A gaseous or liquid fuel that is burned with air, is supplied normally with sufficient pressure, e.g. >1 barg (for gases) and >4 barg (for liquids), so that all burners receive the same amount of fuel and therefore the fuel is evenly distributed.
Normally burners are designed to let pass a certain air flow with the same air damper opening position at the same air side pressure drop, that is to say if the flow rate to all burners is the same, than the measured static pressure in all burners is the same.
In some cases the heat release to individual burners or burner groups can be different from one to another. Customarily the air side pressure drop of all burners is the same, that is to say at maximum heat release of a burner, independent from his size, the pressure drop is the same. If a first burner of a multiple burner system has an air side pressure drop design of 10 mbar at a maximum heat release of 1 MW (Megawatt), a second burner of the same multiple burner system with a max. heat release of 2.5 MW should have the same air side pressure drop of 10 mbar. If this is the case, based on the measurement of the static pressure of each k^thair of each burner the air flow rate of each burner can be determined.
Using the method if the burners of the multiple burner system have different air side pressure drop designs requires, that those pressure values are corrected with the quadratic correlation between flow rate and pressure drop. Thereby the flow rate is dependent of the cross-section of the k^thair channel. The same approach is applicable, if burners of same construction but different heat releases are operated.
A burner comprises at least one air channel, in which one or more air supply modules for the adjustment and/or redistribution of air within the burner exists. Thereby the one or more air channel is connected with the air supply duct and/or flows into it. Such an air supply module is built inside the k^thair channel of a burner and intended to change the cross-section of the air channel, through which the air flows to the burner, whereby it is normally opened more, whereby the air channel with the air supply module among other things can become either fully open, partially open or fully closed. Such an air supply module is typically designed in form of an air damper or depending of the burner construction, e.g. as a within itself rotatable register.
A burner, that has several air channels, has at least one air supply module per air channel. A burner with one air channel respectively a primary air channel has one air module, e.g. a first air module or primary air module. A burner with two air channels and therefore a primary and secondary air supply has two air modules, namely a primary and a secondary air damper. If a burner has three air channels, namely a primary, secondary and tertiary air channel, he comprises three air modules or air dampers that are named primary, secondary and tertiary air dampers.
Single measurements for pressures are done with this method on all burners simultaneously in order to know the air distribution for a specific moment, as the operating status of a furnace can change often and rapidly. The proposed method offers the operating staff the possibility to measure and let indicate directly on site, e.g. directly near the furnace, the air distribution to the burners respectively burner groups. Either the control unit detects the uniform or non-uniform air distribution and consequently makes the changes to the air supply modules accordingly, or the operating staff reads off the air distribution visually and makes the manual changes on the air supply modules. The practically instantaneous response of such changes allows the control unit or the operating staff, to adjust an even or uniform air distribution without big efforts very quickly.
Further advantages of the invention can be derived from the description and the attached figures.
Naturally, the attributes mentioned in the preceding as well as the following sections do not only exist in the combinations outlined, but also apply to other combinations or the single entities, without falling outside the remit of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be represented with the help of the schematic figures and will be consecutively described in more details referring to the figures.

FIG. 1 shows schematically a setup of a burner with primary air supply (FIG. 1b ) and a setup of a burner with primary and secondary air supply (FIG. 1a ).

FIG. 2 shows schematically a first setup of a multiple burner system in different operating states while applying a first way of the inventive method.

FIG. 3 shows schematically a second setup of a multiple burner system in different operating states while applying a second way of the inventive method.

FIG. 4 shows schematically a third setup of a multiple burner system while applying a third way of the inventive method.

FIG. 5 shows schematically a forth setup of a multiple burner system, comprising at least two multiple burner systems as per FIG. 4, while applying a forth way of the inventive method.

The figures will be described coherently and comprehensively, similar references refer to similar components.

DETAILED DESCRIPTION

FIG. 1a shows schematically a first setup of a burner 2 with one air supply channel 8 and two air supply channels 4, 6, who's inlet openings both are connected to a common air duct 8. An exit area of the first air channel 4 is surrounded coaxially by the exit area of the second air channel 6. Thereby the exit area of the second air channel 6 is surrounded and/or bordered by a burner tile respectively a burner tile casing 10. Both air channels 4, 6 flow into the combustion chamber 12 of a furnace. In the first air channel 4 is located downstream of the inlet a first air supply module in form of an air damper 14. In the second air channel 6 is located, downstream of the inlet, a second air module 16, again in form of an air damper.
This first setup of burner 2 has a primary and secondary air supply. During the operation of that burner 2 air respectively combustion air, that is here as well as in the following figures be symbolized with hatched arrows, will be supplied from the air supply duct 8 to the two air channels 4,6. In the first air channel 4 is located and/or is conveyed a first air, also named primary air and is in this figure, as well as in the following figures, symbolized by tight hatching from bottom left to top right. In the second air channel 6 is located and/or is flowing a second air, also named secondary air and is in this figure as well as in the following figures symbolized with a second hatching from top left to bottom right.
Besides on the outer casing of the first air channel 4 there is a first probe 18 respectively measuring probe for the static air pressure inside the first air channel 4 and on the outer casing of the second air channel 6 a second probe 20 respectively measuring probe in order to measure the static air pressure inside that second air channel. The outer casings of both air channels 4, 6 border the burner casing 2 or are identical with the burner casing 2, respectively.
Similar setups of burners 22, 24, 26, 28, 30 with double air supplies, which has the same components like the first setup of burner 2, are put together as components of a multiple burner system 32, 34, like it is schematically shown in the following FIGS. 2 and 3.
A second setup of a burner 36, which is schematically shown in FIG. 1b , shows only a single air supply with one first air channel 38, where downstream of the inlet a first air supply module 40, in form of an air damper, is shown. Along the outer casing of the first air channel 38 there is furthermore a probe 42 located in order to measure the static air pressure in that air channel 38.
It is possible that in a multiple burner system 32 (FIG. 2), 34 (FIG. 3), 44 (FIG. 4), 46 (FIG. 5), that due to different pressure drops, flow profiles, instruments and so forth within an air distribution system, comprising air supply ducts 3,8,84 as well as air channels 4,6,38,80,82, leads to a situation where individual burner groups 72, 72 a, 72 b and/or burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b to some extend vary in the amount of air that is conveyed to those sections. The static pressure is measured with the help of probes 18, 20, 42, 79, that are located on the casings of the individual burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b.
For the burners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b, that are located inside a common air plenum of each burner group 72, 72 a, 72 b the air pressure is measured by probes 79, although those measure the pressure of the plenum of each burner group 72, 72 a, 72 b. The static pressure can be captured and/or measured inside the air channel 4, 6, 38, 80, 82 but also in other places. Normally such a probe respectively measuring probe 18, 20, 42, 79 can also be located elsewhere on the air channel 4, 6, 38, 80, 82 provided that the equivalent static pressure is still representative for the air, that flows inside the air channel 4, 6, 38, 80, 82.
The method envisages, that a measured value, here a static pressure, determines for each burner 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b indirectly a flow rate of combustion air through a burner 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b. If values for the pressure of individual burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b of a multiple burner system 32, 34, 44, 64 are deviating from one another, it is envisaged, that the air supply modules 14, 15, 16, 17, 40, that is to say the air dampers and/or air registers of the burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b are adjusted, respectively opened respectively closed and therefore modified that long, until all burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b have the same static pressure.
Thereby it is envisaged, that the values of the first air pressure (primary air) inside first air channels 4, 80 of all burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b of the multiple burner system 32, 34, 44, 46 are compared with one another. The analogous, values of the pressure of a second air (secondary air) inside second air channels 6, 82 of all burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b of the multiple burner system 32,34,44,46 are compared with one another.
Commonly a multiple burner system 32, 34, 44, 46 comprises a number of burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b, whereby each burner 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b, has several air channels 4, 6, 38, 80, 82, that e.g. are connected via an plenum with a burner group 72, 72 a, 72 b and with air ducts 3, 8, 84, 98. As part of the method for each air channel 4, 6, 38, 80, 8 of each burner 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b the internal air pressure is measured.
Besides all air pressure values of all k^th air channels 4, 6, 38, 80 82 of all burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b are compared with one another.
Since generally all burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b of a multiple burner system 32, 34, 44, 46, on the basis of the heat release, are supposed to be supplied with the same amount of air, it is envisaged in this embodiment of the invention, although not mandatory, to collect the values of all locations where the pressure of the k^thair channel 4, 6, 28, 80, 82 of all burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b is measured and pulled together in at least one location, that is to say in one or more locations, of the multiple burner system 32, 34, 44, 46.
With this measure the values of the static pressure of the k^thair channels 4, 6, 38, 80, 82 are easily comparable with one another and the distribution of individual values, that is to say uniform or non-uniform distribution, easy to be captured and to derive values for the air flow rates through all k^th air channels 4, 6, 38, 80, 82. If static pressure values and therefore flow rates differ from one another, than the values will be readjusted by changing the air supply module 14, 15, 16, 17, 40 settings in the k^thair channels 4, 6, 38, 80, 82 in a way, that they are adapted to the respective heat releases.
FIG. 2 shows schematically a first burner 22, a second burner 24 and a x^thburner 26 of a total of n burners 22, 24, 26 of a first configuration of a multiple burner system 32, that similar to burner 2 of figure la, has a first air channel 4, comprising a first air supply module 14 in form of an air damper and a second air channel 6, comprising a second air supply module 16 in form of an air damper. Furthermore this multiple burner system 32 comprises a primary air duct 3 for all burners 22, 24, 26. This common air duct 3 splits up into secondary air ducts 3, whereby each of these secondary air ducts 8 is connected with both air channels 4, 6 of each burner 22, 24, 26. Air, which is flowing from the primary air duct 3 and/or the secondary air ducts 8, splits into a first air channel 4 and a second air channel 6 for the burners 22, 24, 26 into a second air (secondary air).
As part of the method first probes 18, which are located at the casing of the first air channel 4 of all burners 22, 24, 26 give values for the first static air pressure respectively primary air pressure inside of the first air channels 4. With the help of second probes 20, which are located at the casing of the second air channel 6 or all burners 22, 24, 26 gives values for the second static pressure respectively secondary air pressure inside of the second air channels 6. Assuming that the burners 22, 24, 26 in a variation of the multiple burner system 32 have more air channels, the static air pressure for those air channels would need to be also measured, that is to say in the case of third air channels inside the burners 22, 24, 26, third static pressure respectively tertiary air pressure inside the third air channel of all burners 22, 24, 26 needs to be measured.
The results of the simultaneously executed measurements of the air pressures in both air channels 4, 6 of all burners 22, 24, 26 are captured and displayed for all air channels 4, 6 of all burners 22, 24, 26 by the air pressure measurement device 49 in a central location and/or captured like shown in diagram 50 “Pressure measurement/gauge−primary (white) and secondary air (black)” and automatically displayed. Along the ordinate of a diagram 50 there are shown and made readable values for the static air pressure, respectively. Displaying of the measurements with the help of the pressure measuring device 49 can be done as described, although it is also conceivable to display the pure numerical value without visualization along an ordinate. The central pressure measuring device 49 is connected furthermore with a control unit 51 for control that is to say to drive and/or control functions of the components of the multiple burner system 32. If the air supply modules 14, 16 are not automated, a control unit is not needed and the relevant air supply modules 14, 16 are adjusted manually respectively by hand.
Furthermore FIG. 2a shows a first operating situation of the multiple burner system 32, where it is envisaged, that the cross-sections of all air channels 4, 6 of all burners 22, 24, 26 are opened to maximum, meaning 100% open. Therefore all adjustable air supply modules 4, 6, shown as air flaps, within air channels 4, 6 are positioned parallel to the direction of flow and hence oriented such that they result in minimal flow resistance.
As diagram 50 shows, there are different values for the first air inside the first air channels 4 of all burners 22, 24, 26 as well as for the second air pressure inside the second air channels 6 of all burners 22, 24, 26. The individual values are shown in diagram 50 as white bars 52, 54, 56 for the values of the first air pressure and as black bars 58, 60, 62 with the values for the second air pressure.
In detail the value for the first air pressure of the first air channel 4 of the first burner 22 shows 40 pressure units, normally expressed in mm water column (bar 52). The value of the first air pressure in the first air channel 4 of the second burner 24 is 42 pressure units (bar 54). For the x^thburner 26 the value of the first air pressure in the first air channel 4 is 51 pressure units (bar 56). Therefore the first air pressures for the first air channels 4 of all burners 22, 24, 26 of the multiple burner system 32 differs from one another and as a consequence differs the air flow rate to the burners 22, 24, 26.
The same applies for the values of the second air pressures in the second air channels 6 of all burners 22, 24, 26. Thereby the value of the second air pressure in the second air channel 6 of the first burner 22 is 36 pressure units (bar 58), the value of the second burner in the second air channel 6 of the second burner 24 is 45 pressure units (bar 60) and the value of the second air pressure in the second air channel 6 of the x^thburner 26 is 47 pressure units (bar 62).
Diagram 50 in FIG. 2a shows, that inside the first air channel 4 of the x^thburner 26 exists the highest actual value for the first air pressure among all actual values for the first air pressure 4 of all burners 22, 24 of the multiple burner system 32. Furthermore exists inside the second air channels 6 of the x^thburner 26 the highest actual value of the second air pressure among all captured values for the second air pressure inside the second air channels 4 of all burner 22, 24 of the multiple burner system 32. That means, that the air flow supplied throughout the air supply ducts 3, 8 is higher in flow rate and/or in the fraction of first and second air in burner 26 compared to burner 24 and furthermore higher than the flow in the first burner 22.
As part of the described embodiment of this method differences respectively deviations between actual values for the k^thair pressure in the k^thair channel 4, 6 of burner 22, 24, 26 and a envisaged nominal value for the k^thair pressure in the k^thair channel 4, 6 will be determined and compared with the help of the centrally located pressure measuring device 49.
In order to balance the value variation among the first air pressures, as well among the second air pressures, the embodiment of the method envisages, that air supply modules 4, 6 will be adjusted by the control unit 51 respectively by manual adjustment in controlled manner by changing the cross-section inside the air channels 4, 6. With the described setup it is envisaged, that all values for the pressure of the first air fraction are controlled and/or adjusted to e.g. 50 pressure units and all values for the pressure of the second air fraction to e.g. 45 pressure units and therefore being equalized.
In the here described setup of the method the cross-section of the first air channel 4 of the x^th burner 26 is changed, by the use of the air supply module 14, which is located inside the air channel, reducing the opening by 30% to 70% open position, either by means of the control unit 51 or as an alternative manually. In case of the first air channel 4 of the second burner 24 the cross-section will be changed by opening the air supply module 14 to 80%, whereby the cross-section is reduced by 20%. As a result the actual value of the pressure of the first air will raise from 40 pressure units to the nominal value of 50 pressure units, as normally the total air flow to all burners 22, 24, 26 is kept constant by means of e.g. a control unit of the furnace and/or the burners 26.
For the second air inlet 6 in the x^thburner 26 it is envisaged, that the cross-section is changed by the second air supply module 16, which is controlled by the control unit 51 or manually, by decreasing the opening by 40% to 60% open position. Furthermore will the cross-section of the second air inlet 6 of the second burner 24 be adjusted by controlled adjustment of the second air supply module 16 with help of the control unit 51 or manually reducing the opening by 10% to 90% open position. As a result the actual value for the pressure of the second air fraction of the first burner will increase from 36 pressure units to 45 pressure units.
While adjusting the air supply modules 4, 6 in the k^thair channel 4, 6 of a burner 22, 24, 26 at first it will be determined the difference of an actual and a nominal value in the k^thchannel 4, 6 and the air pressures of the respective burner 22, 24, 26 and from there derived by how much percent a cross-section of the respective k^thair channel 4, 6 of the respective burner 22, 24, 26 must be reduced or enlarged. As soon as it is determined, by how much percent the cross-section of the air channels 4, 6 of a burner 14, 16 is to be reduced, the final cross-section will be adjusted considering the geometry of the air supply modules 14, 16 located inside the air channels 4, 6 by turning the air damper.
In order to balance the values for the air pressures it is not decisive which one has the maximum value. The method envisages, that a burner can be operated on a higher heat release and therefore requires more air. In this case higher air pressures are required compared to those burners that operate on lower heat release. It can be also required, to favor the first compared to the second air and in certain circumstances the first air pressure is higher than the second air. If all burners 22, 24, 26 are of identical construction and all fire the same heat release, meaning the air flow rate to all burners 22,24,26 should be the same and if the values of table 64 are applicable, then the second burner 24 and above all the x^thburner 26 must be adjusted. By throttling the air dampers of the x^thburner 26 air is shifted more towards the other burners 22, 24. Thereby it is considered, that the total air flow, that comes from a fan, is normally kept constant by means of an automated control loop in the DCS (Distributed Control System) of a multiple burner system 32, whereby a non-uniform air distribution to all burners 22, 24, 26 is eliminated.
As part of the method by comparing the pressures, it can be checked, at which burner 22, 24, 26 which air damper needs to be adjusted. Thereby it is not required, to know the absolute total air flow to each burners 22, 24, 26. Instead all relative differences between burner specific air flows, that is to say primary, secondary and tertiary air are compared with one another and in case of deviations be adjusted and/or equalized.
As a result follows a second operating situation for the burners 22, 24, 26 of a multiple burner system 32 that is shown schematically in FIG. 2b . Table 64, which is displayed with the help of the control unit 51, shows among other things, by how much percent the cross-section of the air channels 4, 6 of the individual burners 22, 24, 26 is to be opened or as an alternative if the air dampers are adjusted manually it can be determined by reading off the physical positions on the dampers. The bar 152, 154, 156, 158, 160, 162 in diagram 150 shows, that in the first air channel 4 of all burners 22, 24, 26 now the same air pressure with a value of 50 pressure units exists. The values of the second air pressure in the second air channel 6 of the burners is 45 pressure units.
Based on FIG. 2c a method is described, for with which the air supply to a multiple burner system 32 can be optimized, if the heat release to the burners 22, 24, 26 is different from one another. It is assumed, that the heat release of the first and second burner 22, 24 is 1 power unit (e.g. Megawatt)—see table 264. The heat release of the x^thburner 26 is 20% higher meaning 1.2 power units. As a consequence the air flow required for the x^thburner 26 must be 20% higher compared to the other burners 22, 24. By how much the respective pressure of the respective air must be higher, derives from the quadratic correlation between pressure drop Δp_k, that is to say the pressure drop Δp₁of the first air and the pressure drop Δp₂of the second air, as well as the cross-section A_ifor the respective k^thair fraction, according the proportionality ratio Δp₁=Δp₂˜(proportional) (A₂/A₁)²respectively Δp₁=Δp₂˜(ΔV₁/ΔV₂)², whereby ΔV_iis a respective flow rate.
For the x^thburner 26 this means, that the pressure of the k^thair must be adjusted by the factor (1.2/1)², that is to say 44% higher than the other burners 22, 24. This can be accomplished by opening/closing of a respective air supply module 14, 16. In that way it is possible, to use the pressure measurement device 49 not only in order to balance the air supply to the burners 22, 24, 26 when operating at same heat releases, but also when the burners 22, 24, 26 are operating on different heat releases, so that finally the mixture of fuel and air is adjusted to every burner 22, 24, 26 adequately.
Considered here is also that the combustion chamber internal pressure, which is connected with the burner 22, 24, 26 and a pressure of ambient air, whereby the pressure inside the combustion chamber is normally negative. Considering additionally the pressure values inside the combustion chamber, as well as the ambient air and the pressure in the air channels 4, 6 the values for the air pressures of the first and second air of the first and second burner 22, 24 will be balanced, compare to bar 252, 254, 256, 258, 260, 262 in diagram 250. Therefore the air pressure of the first air in the first air channel 4 of the first burner 22 (bar 252) matches the air pressure of the first air in the first air channel 4 of the second burner 24 (bar 254) and the air pressure of the second air in the second air channel 6 of the first burner 22 (bar 258) matches the air pressure of the second air in the second air channel 6 of the second burner 24 (bar 260).
FIG. 3 shows schematically a second setup of a multiple burner system 34 with two burners 28, 30 that each has two air channels 4, 6 and similar to previous burners 12, 22, 24, 26 as per FIGS. 1a, 2a and 2b are connected with one air supply duct 8. FIG. 3 shows furthermore a measuring setup 70 for the control of the operation of a multiple burner system 34, as well as at least one step of the embodiment of this method. Besides also here each combustion chamber has a probe respectively measuring probe 13 in order to measure the pressure.
As shown schematically in FIG. 3a , one first probe 18 is connected on the casing of a first air channel 4 of the first burner 28 via a first connection, e.g. in form of an air hose, to a first leg of a first “U” type pressure measuring device 66. A first probe 18, attached on the casing of a first air channel 4 of the second burner 30, is connected via a second connection, e.g. in form of an air hose, to a second leg of a first “U” type pressure measuring device 66. The level of the “U” type pressure gauge liquid shows, that the first air pressure in the first channel 4 of the first burner 28 has a higher pressure than the first air pressure in the first air channel 4 of the second burner 30.
A second probe 20 attached on the casing of a second air channel 6 of the first burner 28 is connected via a third connection, e.g. in form of an air hose, to a first leg of a second “U” type pressure measuring device 68. A second probe 20 attached on the casing of a first air channel 6 of the second burner 30 is connected via forth connection, e.g. in form of an air hose, to a second leg of a “U” type pressure measuring device 68. The level of the liquid of the “U” type pressure measuring device shows here, that the second air pressure in the second air channel 6 of the first burner 28 is higher than the second air pressure in the second air channel 6 of the second burner 30.
In this setup cross-sections of the air channels 4,6 of the first burner 28 will be reduced by adjusting the internal air supply modules 14, 16 and therefore reduces the values for the existing air pressures, until inside the first air channels 4 of both burners 28, 30 the same first air pressure and in the second air channel 6 of both burner 28, 30 the same air pressure is achieved, which finally leads to same liquid level in the “U” type pressure measuring devices 66, 68—as indicated in FIG. 3 b.
In this shown setup with only two burners 28, 30 of same air side pressure drop design, the probes 18, 20 for the measurement of the air pressures are connected to one leg of the “U” type pressure gauge. However any other pressure measuring device 66, 68 can be used to capture and/or compare the pressure values. With the here presented setup it is possible to equalize and/or even out the pressure values of a non-uniform distribution of air in both, the first air channels 4 as well as in the second air channels 6, of both burners 28,30 of a multiple burner system 34.
A forth setup of a multiple burner system 44 is shown schematically in FIG. 4 comprising a burner group 72 with a distribution chamber, which is also called a “plenum”. If a multiple burner system comprises of more plena, one burner group 72 is arranged within a respective plenum.
FIG. 5 shows two such burner groups 72 a, 72 b with plena, which constitute another configuration of a multiple burner system 46. However it could be any number of burner groups 72, 72 b.
Every burner group 72, 72 a, 72 b consists of several burners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b of which in FIGS. 4 and 5 are shown a first burner 74, 74 a, 74 b, a second burner 76, 76 a, 76 b and a y^thburner 78, 78 a, 78 b. Each of these burners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b comprises one first internal air channel 80 and a second internal air channel 82. Thereby via every first internal air channel 80 a first air respectively primary air is supplied to a combustion chamber 12 of a furnace, whereas via every second internal air channel 82 a second air respectively secondary air is supplied to the combustion chamber 12.
At the casing of the plenum of a burner group 72, 72 a, 72 b there is arranged at least one air duct 3, by which air is supplied to the plenum in which the burner group 72, 72 a, 72 b is located.
At least one air duct 3 is coupled to an air duct 84 that sits across the burner and/or within a distribution plenum. The air channels 80, 82 inside the burner are thereby coupled to the superordinate air duct 84 that sits across the burner and/or within a (distribution) plenum and is generally identical with the (distribution) plenum itself.
Therefore air flows from at least one air supply duct 3 into an air duct 84 that sits across the burner and/or within a distribution plenum. This air splits up for each burner 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b separately throughout the burner internal air channels 80, 82 into fractions, namely a first air inside the respective first air channel 80 as well as a second air inside the respective second air channel 82.
The air, which is supplied from at least one air duct 3 and/or the plenum internal air duct 84, will be distributed freely within each plenum comprising the burner groups 72, 72 a, 72 b. The internal space of the plena 72, 72 a, 72 b of the burner groups 72, 72 a, 72 b, which is formed by the superordinate air duct 84 and the burners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b provides air supply to all burners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b. When air is arriving at the burners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b, the air will be routed through the air channels 80, 82 by opening and/or closing of the air supply modules 15, 17.
It is envisaged, that along the burner enclosing and/or internal plenum internal air duct 84 respectively on the plenum of burner group 72, 72 a, 72 b at least one measuring probe 79 is arranged, with which the air pressure is measured. As in this method merely the air pressure values inside the plenum of a burner group 72, 72 a, 72 b are measured, only the air flow of an entire plenum of one burner group 72, 72, 72 b is comparable to another plenum of another burner group 72, 72 a, 72 b. This approach can be helpful because in this setup respectively way of construction of air supply modules 15, 17 the measurement of air pressure inside the air channels 80, 82 can be difficult.
The in FIG. 5 schematically shown setup of a multiple burner system 46 comprising x burner groups 72 a, 72 b as presented already in FIG. 4, whereby here only one first burner group 72 a (plenum 1) and a x^thburner group 72 b (plenum x) is shown. Each of those burner groups 72 a, 72 b comprising here one plenum with a total of y burners 74 a, 74 b, 76 a, 76 b, 78 a, 78 b with a first and a second internal air channel 80, 82 each. Analogous to the multiple burner system 44 shown in FIG. 4, the air is supplied via the burner enclosing and/or plenum internal air duct 84 by distributing freely towards the y burners 74 a, 74 b, 76 a, 76 b, 78 a, 78 b.
During the operation of the multiple burner system 46 the combustion air is supplied from a reservoir and/or a fan 96 via an air duct system 98, in which valve and/or dampers respectively air supply modules 100 are arranged, guiding the air to several air ducts 3 and finally leading to the burner groups 72 a, 72 b. The supplied air is split up inside of the plena of the burner groups 72 a, 72 b.
Along at least one air duct 3 of the first burner group 72 a are arranged at least one, here several measuring probes 79 in different locations, that are connected with a first intersection 102 for all measuring probes 79. At this first intersection point 102 the air pressure inside the plenum 74 a is measured. The value for the air pressure is determined and if applicable directly displayed by a central located pressure measuring device 104 in form of a diagram 106 and visible as a first white bar. Similarly, there are several measuring probes 79 at different measuring points along one air duct 3 of the x^thburner group 72 b, that connect all measuring probes 79 with the x^thintersection 108. At this x^thintersection 108 the air pressure for the x^thburner group 72 b and therefore for that plenum is measured. An air pressure value for burner 74 b, 76 b, 78 b of the x^thburner group 72 b is also captured by the central pressure measuring device 104 and displayed in diagram 106 by means of a second, black bar. The central pressure measuring device 104 acts together with a control unit 110 for the control of the multiple burner system 46 applying the method. As an alternative the multiple burner system 46 can also be operated manually that is to say without a control unit 110.
To modify the measured air pressure or air flow values, respectively, the cross-sections of the air ducts are changed by adjusting the air supply modules 100 considering the proportionality P_nom./P_act.˜(A_act./A_nom.)²or P_nom./P_act.˜(V_nom./V_act.)², respectively. In this configuration, the total air flow for each plenum are compared with one another. Normally there are no separate plena for the first or second air. Each plenum supplies the first and second air in the same manner. Air flows for the individual burners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b or the k^thair channel are thus no longer distinguishable. A position of the k^th air supply module 15 is hence the same for all burners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b of the same plenum. This also applies for the k^th air supply modules 17, whereby the position of all air supply modules 15 can be different to those of air supply modules 17, e.g. the air supply modules 15 can be opened 30% and air supply modules 17 100%.
As diagram 106 shows, the air pressure value in the first burner group 72 a is lower than in the x^thburner group 72 b. If all burners 74 a, 74 b, 76 a, 76 b, 78 a, 78 b of all burner groups 72 a, 72 b are operated with the same heat release, hence requiring the same air quantities, the x different air pressure values are equalized by controlled adjustment of at least one air supply module 100. This module is arranged along the at least one air supply duct 3, that leads to the first burner group 72 a and increases the air while opening the air supply module 100 until both plenum specific values are the same. As an alternative the air supply module 108 of the second burner group 72 b can be closed more.
If different heat releases are run in burner groups 72 a, 72 b, then the air pressure needs to be adjusted according to the quadratic relationship between pressure, and pressure drop respectively, and the cross-section of the air channels 80, 82 as already described in FIG. 2.
The concept as described in FIGS. 2 and 3 is basically also usable for groups of burners 74, 74 a, 76, 76 a, 78, 78 a within burner groups 72, 72 a, 72 b, if individual measurements at each burner 74, 74 a, 76, 76 a, 78, 78 a are possible.
Furthermore, the described method to measure the air distribution can also be used for furnaces with natural draft burners without air ducting. In that case, pressure values of a combustion chamber 12 will be measured via parallel measurements with several measuring probes 13 of the combustion chamber 12, by comparing the direct simultaneous readings.

Claims

1. Method for operation of a multiple burner system (32, 34, 44, 46), comprising

two or more burner groups (72, 72 a, 72 b),

wherein each burner group (72, 72 a, 72 b) is associated with at least one air intake duct (3, 8, 84, 98) through which air is supplied to the burner group (72, 72 a, 72 b),

wherein each burner group (72, 72 a, 72 b) has at least one k^thair channel (4, 6, 38, 80, 82) with which the supplied air is divided up into an k^thair,

wherein for each k^thair channel (4, 6, 38, 80, 82) of all burner groups (72, 72 a, 72 b) an air pressure value is measured for the k^thair for all burner groups (72, 72 a, 72 b),

wherein all air pressure values measured for k^thair for the burner groups (72, 72 a, 72 b) are compared with one another, to determine whether the air pressure values for the k^thair for the burner groups deviate from one another,

wherein deviating arc pressures for the k^thair are changed inside the k^thair channel (4, 6, 38, 80, 82).

2. The method as in claim 1, in which all measured air pressure values for the k^thair are collected at one location and compared with one another.

3. The method as in claim 1, performed for a multiple burner system (32, 34, 44, 46) with a number of burner groups (72, 72 a, 72 b), wherein each burner group (72, 72 a, 72 b) comprises at least one burner (2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b), wherein each burner (2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b) is associated with at least one air supply duct (3, 8, 84, 98), through which the burner (2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b) is supplied with air, wherein each burner (2, 22, 24, 26, 28, 30,36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b) has the k^thair channel (4, 6, 38, 80, 82), with which the air supplied is divided up into the k^thair, wherein for each k^thair channel (4, 6, 38, 80, 82) for all burners (2, 22, 24, 26, 28, 30,36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b) the air pressure value for the k^thair is measured, wherein all air pressure values measured for the k^thair are compared with one another to determine whether the air pressure values for the k^thair for the burners (2, 22, 24, 26, 28, 30,36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b) deviate from one another, wherein deviating air pressure values for the k^thair are changed within the k^thair channel (4, 6, 38, 80, 82).

4. The method as in claim 1, in which an air pressure value for the k^thair channel (4, 6, 38, 80, 82) is changed by changing the cross-section of the k^thair channel (4, 6, 38, 80, 82).

5. The method as in claim 1, in which an air pressure value for the k^thair channel (4, 6, 38, 80, 82) is changed by changing at least one air supply module (14, 15, 16, 17, 40, 100) located inside the k^thair channel (4, 6, 38, 80, 82).

6. The method as in claim 5, in which the air pressure value for the k^thair is changed inside the k^thair channel (4, 6, 38, 80, 82) with at least one air supply module (14, 15, 16, 17, 40, 100) designed as an air damper.

7. The method as in claim 4, in which the air pressure of the k^thair in the k^thair channel (4, 6, 38, 80, 82, 84) has an actual value of p_act.and the cross-section of the k^thair channel (4, 6, 38, 80, 82, 84) has an actual value of A_act., wherein for the cross-section of the k^thair channel (4, 6, 38, 80, 82, 84) a nominal value of Anom. is set, wherein for the air pressure of the k^thair in the k^thair channel (4, 6, 38, 80, 82, 84) a nominal value of p_nom.is set, wherein P_nom./P_act.is proportional to (A_act./A_nom.)².

8. Setup for operation of a multiple burner system (32, 34, 44, 46), comprising two or more burner groups (72, 72 a, 72 b), wherein each burner group (72, 72 a, 72 b) is associated with at least one air intake duct (3, 8, 84, 98), through which air is supplied to the burner group (72, 72 a, 72 b), wherein each burner group (72, 72 a, 72 b) has at least one k^thair channel (4, 6, 38, 80, 82), with which the supplied air is divided up into an k^thair, wherein the setup includes at least one pressure measuring device (49, 66, 68, 104) designed for measuring an air pressure value for the k^thair for each k^thair channel of all burner groups (72, 72 a, 72 b) wherein all air pressure values measured for k^thair for the burner assemblies (72, 72 a, 72 b) are to be compared with one another, to determine whether the air pressure values for the k^thair for the burner groups (72, 72 a, 72 b) deviate from one another, wherein deviating air pressures for the k^thair are to be changed inside the k^thair channel (4, 6, 38, 80, 82, 84).

9. The setup as in claim 8, in which at least one pressure measuring device (49, 66, 68, 104) is located centrally and designed to simultaneously measure all air pressure values for the k^thair.

10. The setup as in claim 8, comprising a number of probes (18, 20, 42, 79) for measuring the air pressure, wherein along the k^thair channel (4, 6, 38, 80, 82, 84) at least one probe (18, 20, 42, 79) is located, which is connected to at least one pressure measuring device(49, 66, 68, 104).

11. The setup as in claim 8, comprising at least one air supply module(14, 15, 16, 17, 40, 100) located inside the k^thair channel (4, 6, 38, 80, 82, 84), designed to change a cross-section of the k^thair channel (4, 6, 38, 80, 82, 84).

12. -The setup as in claim 8, comprising a control unit (51, 110) designed to compare all air pressure values measured for the k^thair of all burner groups (72, 72 a, 72 b) with one another and to determine whether the air pressure values for the k^thair of all burner groups (72, 72 a, 72 b) deviate from one another, wherein the control unit (51, 110) is designed to change the cross-section of the k^thair channel (4, 6, 38, 80, 82, 84) and compensate any deviating air pressure value for the k^thair within the k^thair channel (4, 6, 38, 80, 82, 84).