EP3403027A1

EP3403027A1 - Analysis and regulating method for multi-fuel burners, and analysis and regulating assembly for same

Info

Publication number: EP3403027A1
Application number: EP16831482.1A
Authority: EP
Inventors: Markus Vogelbacher; Hubert Keller; Patrick Waibel; Jörg Matthes; Hans-Peter Friedrich
Original assignee: Ci-Tec GmbH; Karlsruher Institut fuer Technologie KIT
Current assignee: Ci-Tec GmbH; Karlsruher Institut fuer Technologie KIT
Priority date: 2016-01-15
Filing date: 2016-12-22
Publication date: 2018-11-21
Anticipated expiration: 2036-12-22
Also published as: WO2017121449A1; EP3403027B1; DE102016000290A1; PL3403027T3

Abstract

The invention relates to an analysis and regulating assembly and to an analysis and regulating method of a multi-fuel burner for alternative fuels. The multi-fuel burner (1) has a measuring and regulating assembly (10) which has an infrared camera (4) that is paired with a burner mouth (3) of the multi-fuel burner (2), a data processing unit (6), and a regulating and control unit (7). The data processing unit (6) is operatively connected to the regulating and control unit (7) and the infrared camera (4). A current combustion image in the infrared spectral range is captured by means of the infrared camera (4) during a combustion process, and the combustion image indicates image data of a captured section (A) which comprises the combustion mouth (3) and contains substitute fuel particles (5). The substitute fuel particles (5) are ascertained from the image data using a data processing unit (6), and current characteristic combustion parameters are determined. The combustion parameters are compared with specified target combustion parameters. If the current characteristic combustion parameters deviate from the target combustion parameters, regulating and/or control parameters in the regulating and control unit (7) are adapted.

Description

The invention relates to an evaluation and control method for multi-fuel burners and to an evaluation and control arrangement for carrying out the method.

In the cement industry, especially in the field of clinker production, raw materials must first be thermally converted. The thermal conversion of raw material to clinker takes place with the aid of a rotary kiln. The thermal energy at the different points of the cement plant is provided by multi-fuel burners, which make it possible to increase the proportion of alternative fuels (eg fluff, plastic shreds, tire flakes or meat-and-bone meal), thus reducing costs and reducing emissions.

So far, the share of substitute fuels in the total fuel could not be kept stable at high levels (> 70%), since alternative fuels have properties such as a strongly fluctuating moisture content, which have a great impact on the combustion and the produced fuel gases and the final product. Falling, not completely burned fuel ends up in the production process of the raw materials during this production process and thus even has a direct impact on the chemical conversion process and thus on the corresponding end product. For a consistently high proportion of alternative fuels, a permanent monitoring of the fuel and the process state is necessary. Previously existing measuring systems were only able to record the process status with a time delay, which makes rapid intervention with fluctuating fuel properties impossible. For example, changing fuel properties in fuel-flow behavior can not be detected with cameras in the visually-visible wavelength range, which are often used in process monitoring control stations.

Based on this prior art, it is the object of the present invention to provide an improved evaluation and control method for multi-fuel burners in order to be able to increase or to keep the proportion of substitute fuels high.

This task is performed by an evaluation and control procedure with the characteristics of the

CONFIRMATION COPY Claim 1 and solved by the corresponding evaluation and control arrangement with the features of the independent claim 7.

Further developments or preferred embodiments of the evaluation and control method as well as the evaluation and control arrangement are set forth in the subclaims.

A first embodiment of an evaluation and control method according to the invention is carried out with a multi-fuel burner for alternative fuels, which has a measurement and control arrangement which has an infrared camera which is assigned to a burner mouth of the multi-fuel burner. Further, the multi-fuel burner is associated with a data processing unit and a control and control unit, which are operatively connected to each other and to the infrared camera. In a step a), a current focal image in the infrared spectral range is recorded with the infrared camera during a firing process, wherein the focal image image data of a receiving portion which includes the burner mouth and contains the substitute fuel particles shows. In the subsequent step b), the image data of the focal image are sent to the data processing unit and there in step c) with the data processing unit from the image data, the substitute fuel particles and size and position of a plurality _. , _: u

uuci au anci r ai ni \ ci ci 1 1 ii nci i. From the data acquired in step c), in step d), current characteristic firing parameters are determined and these are compared with predetermined target firing parameters.

Further, in step e), when the actual combustion parameters deviate from the desired combustion parameters in the control and regulation unit, the control and / or control parameters that correlate with the characteristic combustion parameters are adjusted, thereby changing the characteristic combustion parameters until the current characteristic combustion parameters Correspond to nominal firing parameters. Finally, the process can be carried out continuously, for which purpose the abovementioned steps a) to e) are repeated continuously.

By means of the method, combustion of substitute fuel can be extensively monitored, measured and evaluated and used to evaluate the combustion. In this case, the entire period of combustion, d. H. from the entrance of the fuel into the burner, leakage of the fuel from the burner mouth, whose flight behavior up to combustion of the substitute fuel in the combustion chamber, are observed. In this case, a fuel goes from a cold, non-ignited state to an ignition within the burner and eventually burns completely, ideally completely. Some fuels do not or only partially burn - this too can be detected with the method according to the invention, so that the burning behavior of substitute fuels can be better understood and the proportion in a combustion process can be substantially increased.

"Combustion parameters" or combustion parameters in the sense of the invention are all image-based parameters that can be recorded from the image data or the image taken by the infrared camera or determined by the subsequent evaluation The combustion parameters describe the state or can update the state of the combustion and "over a certain time." "Control and / or control parameters" in the sense of the invention are all known manipulated variables which can serve to set the burner and to influence the burning process sustainably. The invention relates to an evaluation and control method, wherein a pilot control can be included with respect to the fuel composition.

For the purposes of the invention, "adjusting the firing parameters" means that the firing parameters can be approximated to target values, and thus they form dynamic values that constantly change and, ideally, approximate target specifications.The term "current" is always to be seen at a specific time , and changes over time or adapts. Actual values at a first time for certain burner settings may easily be different than current values at a second time for certain burner settings. The "burning process" within the meaning of the invention is everyone Ignition and combustion process and each exit and flight behavior of substitute fuel. A "combustion picture" in the sense of the invention shows a picture of the entire combustion process - such as fuel supply from the burner mouth, ignition behavior of the fuel and its combustion behavior.

With the evaluation and control method according to the invention, it becomes possible to monitor a burner during the firing process almost seamlessly by the use according to the invention of an infrared camera. When using an infrared camera with a special spectral filter, the combustion gases become much more permeable to radiation (virtually transparent). This makes it possible to detect the fuel in the recordings. When measured in the visual spectral range, the flame would obstruct the view of the substitute fuel. Therefore, the camera provides insight into the combustion process by showing the existing combustion gases through the detection by means of infrared and thus detection of a not directly visible particle fraction. It can be made possible to understand the change in the fuel properties and to correct immediately if necessary. It can be manually controlled or controlled, wherein the required evaluation and control parameters can be set manually by displaying the KamerabiJdes in a control room and the specific firing parameters in one embodiment. Alternatively, the control or regulation can also take place automatically, for which purpose the firing parameters can be gradually adapted by the method according to the invention by means of the evaluation and control unit.

The resulting parameters or firing parameters determined from an imaging process can be used for controlling the firing process, whereby the burner parameters can be further adjusted. The changing fuel properties are reflected in the infrared camera shots, among other things, by intensity differences within the recording, dynamic changes over time and by model deviations. For this purpose, various parameters are used, for example, to map the intensity differences and dynamic changes of the particle positions over time and to supply further calculations. Thus, the invention can provide that for determining or also segmenting the substitute fuel particles from image data of one or more images / images one or more parameters temperature, intensity, speed amount, speed direction and probable position of a particle due to previously known Temperature or probability or speed models is determined and further from image data of two or more images, a speed of the firing process is determined. The models used are based on process knowledge that corresponds to a knowledge of combustion processes that is known to the person skilled in the art and that results from the scope of combustion.

Various image processing methods can be used. In this case, a method may preferably be used according to which image preprocessing first takes place, in which contrast-enhancing image processing methods are first applied to a single image and a reduction takes place to an interest region ("region of interest"), in which, for example, a plurality the particle is statistically suspected.

After this image preprocessing, a so-called segmentation takes place. A texture filter is placed over the area of interest, after which further segmentation into particles or particle agglomerations can take place. There is the possibility that a region is already removed from the segmentation, if in this further, to be tested properties, such. B. size, position, distance to the burner mouth, etc. can be seen. Also, in certain regions, the aforementioned properties can be checked separately and, if the specifications for the properties are not fulfilled, the region can be removed from the segmentation. It is also possible to perform temporal filtering of the image data (e.g., temporal average filters) to more clearly delineate image areas with fuel from other image areas. The segmentation of the fuel on the basis of individual images and the segmentation on the basis of the temporal filtering of an image sequence can be advantageously combined, for example with the aid of a maximum-a-posteriori estimation, in order to achieve an improvement in the segmentation accuracy.

After this segmentation, a characteristic size extraction can take place. Properties of individual particles can be calculated on the basis of the segmentation in individual images (eg size, distance to the next particle, location / position, agglomeration yes / no). On the basis of the segmentation of temporally filtered image data and on the basis of the combination of the two segmentations, further parameters can be determined by calculation. It can be calculated for each image column a normal distribution (mean and standard deviation) for the stay of fuel. Based on these distributions Among other things, the average trajectory of the fuel and the distribution behavior or scattering behavior of the fuel in the flight phase can be calculated.

The invention provides that one or more characteristic firing parameters such as position, size, distribution, mean trajectory, combustion time, distribution behavior or scattering behavior of the substitute fuel particles in the combustion chamber can be selected. Advantageously, additional information is determined from the image data, which can be used for an analysis of the burning process within the combustion chamber. The invention further provides in a continuation that in a step c ') from the image data further, the characteristic combustion parameters complementary characteristics are determined, such as. Agglomerations of the substitute fuel particles or a probability of residence of the substitute fuel particles in a combustion chamber of the burner , Furthermore, a combustion time of the substitute fuel particles after leaving the burner mouth or an impact position or an impact time of the substitute fuel particles in a solid bed in the combustion chamber can be determined. The distribution of the substitute fuel particles during a flight phase of the same can also be determined from the image data. The method can thus serve to safely and comprehensively monitor a firing process and to obtain a lot of data on different fuel fractions and compositions.

Furthermore, at least one control and / or control parameter such as primary air quantity, secondary air quantity, proportion of the substitute fuel, angle of a pneumodeflector or twisting of the air (also called "swirl") can be set for the regulation or control of the burner ; for suitable settings, empirical values are used.

In addition to monitoring and control of the firing process, the invention can provide that on the basis of the infrared camera recordings and subsequent image processing, current and stored detected firing parameters can be compared with predetermined target firing parameters. From this, the burning behavior can be determined and evaluated according to predetermined criteria. Thus, there are quality criteria for various materials - for example, the proportion of free lime is a quality criterion for fired clinker. Furthermore, the temperature in the oven or on certain areas in the oven or a desired flight behavior or combustion time are used as a quality criterion and also serve as a target parameter. Furthermore, the combustion state can also be taken into account directly if z. B. is to prevent that substitute fuel lands in the fuel bed. For this purpose, the setpoint parameters can be adjusted accordingly.

Since the actual combustion behavior is shown solely on the basis of the calculated combustion parameters, the desired parameters alone can only be used to a limited extent for evaluation. However, if, for example, a deviation from a desired combustion time point or a deviation from the desired mean flight curve is to be used for the evaluation, the setpoint parameters can also be included in the evaluation.

In one embodiment of the invention, it is provided that an evaluation and subsequent evaluation can be carried out. This information can be used to discover characteristics of different fuel compositions and make predictions about their combustion process.

Advantageously, the infrared camera image can be used to detect the fuel and to derive characteristics such as the exit and flight behavior, which is divided into a flight curve, material scattering during the flight and a landing zone. The combustion time of the particles can also be determined. It may be thrown back on the alternative Brennsioffanieii and thus made an assessment of the scattering behavior. As a result, the properties of the fuel and the characteristic firing parameters can be monitored almost in real time and reacted early with changes. Different regulatory strategies can be used to further increase the share of alternative fuels. On the whole, the invention offers the advantage that the monitoring makes it possible to use an overall higher proportion of alternative fuels in the total fuel for industrial combustion processes, without having a negative influence on the overall burning process and ultimately on the product quality.

The invention further provides an evaluation and control arrangement for carrying out the method according to the invention. The arrangement has a burner with a burner mouth and an infrared camera for receiving substitute fuel particles in the Infrared spectral range, wherein the infrared camera is arranged in front of the burner mouth, that the burner mouth and a flame in front of the burner mouth in the receiving portion of the infrared camera is located. Furthermore, the arrangement comprises a data processing unit which is operatively connected to the infrared camera and a control and control unit of the burner.

Advantageously, the invention can be used to analyze the escape and flight behavior of alternative fuels in industrial multi-fuel burners on the basis of images from infrared cameras, since this type of evaluation and control arrangement can promptly record a combustion process state by using the method according to the invention.

Other embodiments as well as some of the advantages associated with these and other embodiments will become apparent and better understood by the following detailed description with reference to the accompanying figures. Items or parts thereof that are substantially the same or similar may be provided with the same reference numerals. The figures are merely a schematic representation of an embodiment of the invention. Showing:

1 is a schematic view of a monitoring arrangement according to the invention,

2 shows a schematic side view of a receiving section of the infrared camera with detected substitute fuel particles,

3 shows a schematic view of a distribution of the substitute fuel particles,

4a-f photographic view of a burner mouth with emerging substitute fuel particles at different burner settings,

5 is a photographic view of an image-processed recording,

6 is a processed photographic image with detected particles, and

Fig. 7 is a graph showing the distribution of the particles.

In Fig. 1, the monitoring assembly 10 shows a multi-fuel burner 1 with a combustion chamber 2 and a burner mouth 3. The combustion chamber 2 is preceded by an infrared camera 4, which can accommodate a receiving section A. The infrared camera 4 is operatively connected to a data processing unit 6 via data lines 9. These has a memory 6a in which the parameters, values and models required for evaluation and control or regulation are stored. Furthermore, the data processing unit 6 is connected to the control and regulation unit 7. This, in turn, is operatively connected to the burner 1, so that the control and regulation unit 7 can influence the combustion parameters of the combustion process by changing or adapting control and regulation parameters.

In Fig. 2, the receiving area A of the infrared camera 4 is shown schematically, with a flame 11 from the burner mouth 3 extends into the combustion chamber 2 into it. Within this flame 11, there are substitute fuel particles 5, which are carried in a specific trajectory F out of the burner mouth 3. After a certain time, which depends on the nature and the material of the respective substitute fuel used, these particles burn 5 or residues of the substitute fuel fall to the bottom of the combustion chamber 2 and form a solid bed. 8

FIG. 3 schematically shows an exemplary distribution of the substitute fuel particles 5, wherein the particles 5 fly within a jet trajectory F with a mean trajectory F 'out of the burner mouth 3 into the burner space 2. The particles 5 can move alone or also form agglomerations 5 '. Furthermore, coal regions K are formed at the burner mouth 3. The illustrated multi-fuel burner 1 has, for example, two fuel feeds. A centrally located in the burner mouth supply for the substitute fuel. Another fuel supply is located coaxially around the center-mounted fuel feed and serves as a feed to the standard fuel, coal. Two feeds are necessary as coal and substitute fuel are often burnt together. The coal areas K show the areas where the coal exits the burner and then burns in the furnace. It burns quite fast, so that the area K is laterally in front of the burner mouth compared to the slower burning substitute fuel. If no coal burned, z. For example, when 100% substitute fuel is used, there is no coal region K. FIG. 3 shows a scheme of combustion with some coal so that the carbon regions K are formed.

FIGS. 4a to 4f show photographic images of an infrared camera 4 for various settings of the burner 1. From the burner mouth 3, the flame extends 11 in the burner chamber 2 inside, in which the particles are 5. Infrared images show particles 5 in a dark, almost black gray; the flame 11 can be seen around it in medium gray. The six individual photographic images of FIGS. 4a to 4f represent a sequence of a continuous burning process, wherein different presettings have been made on the burner 1, which lead to the different focal images. The settings of the burner 1 here are the parameters EBS (proportion of the substitute fuel in percent), the pressure of the pneumodeflector in mbar and a twisting (also called "swirl") The twisting or air turbulence is unitless and refers in the following numerical example to a Adjustment on the burner 1 and can be between a value of 1 and a value of 9. These three parameters are briefly summarized in the following table and show how the parameter settings can influence and also focus a particle beam in its trajectory.

By means of an imaging method, which is based inter alia on the evaluation of various variables, such as the temperature, the brightness, intensity of the flame 11 and a general distribution of the particles 5 in the infrared range, size and position and thus the individual particles 5 themselves (the 5 are shown as small crosses), as shown in FIG. 5, a photograph of the recording area for an exemplary burner setting. From the position and the size of the particles 5, a distribution can be calculated, from which their trajectory F and also an average trajectory 5 'can be determined. In addition, the maximum exit angle W of the total fuel at the burner mouth 3 (in FIG. 5 by means of two lines W on the left and right of FIG Burner mouth 3 shown) are analyzed. The drawn rectangle designates a region of interest R, which is limited to the image analysis, in which area "search" and analysis are carried out after the particles 5. Fig. 6 shows an already processed image which makes it possible to take a look at the image Based on this image, for example, individual particles 5 can be detected, whereby only the area in front of burner mouth 3, ie in a realistic flight range of the fuel, is considered.

If these particle detections are observed over a longer period of time, a kind of hit list can be created as shown in FIG. The particles 5 are determined and their properties, such as size, position and distribution can be further processed by calculation, as shown in FIG. 7. The individual particle detections of replacement fuel particles are marked as small crosses. From these detections, further, a column-by-column estimation for the location of the fuel can be made, and for a small number of columns of particle detections, the mean (thick crosses centered) and the standard deviation (crosses above and below the mean values) are formed. From this a normal distribution is derived. The dimensions on the graphene axes correspond to those of a so-called interest region or "region of interesf. FIG. 7 shows a section of such an interest region and the Gaussian estimates (lines G) of selected estimates within the region of interest R corresponding to the associated mean values and above and below the Ισ interval of these particle detection estimates. The continuous curves represent estimated normal distributions for the location of particles in each column (based on the means and standard deviations). With the help of the detections, a trajectory estimation can be carried out in a further step. From the graph can therefore on the trajectory F and the mean trajectory F 'of the particles 5 are closed.

For camera-based detection of the exit and flight behavior of substitute fuel particles of an industrial multi-fuel burner 1 and its regulation and control, the substitute fuel particles 5 can be detected by means of the infrared camera 4 and with the aid of an imaging method. On the basis of the calculated image-based parameters of the substitute fuel particles 5, parameters which are suitable for characterizing the exit-flight behavior of the particles 5 can be determined. These parameters can then readily be included in the regulation of the multi-fuel burner 1 and implemented by the control and regulation unit 7.

It is advantageous, in particular, that by means of the imaging method preferably a camera technology is used which is sensitive in the infrared spectrum. In this case, the infrared technology offers the particular advantage that smoke formation and other parts of the image that are obstructive in the visible spectrum are not detected, but only the image components likewise reflecting in the infrared spectrum, such as particles 5 or other solids, and their behavior in the combustion chamber 2 can be monitored and evaluated ,

LIST OF REFERENCE NUMBERS

1 multi-fuel burner

2 combustion chamber

3 burner mouth

4 infrared camera

5 substitute fuel particles

5 'agglomerations

6 data processing unit

6a memory

7 control unit

8 solid bed

9 data lines

10 surveillance arrangement

11 flame

A recording section

F trajectory

F 'Medium trajectory

K coal area

R area of interest

G line of the Gauss estimate

W exit angle

Claims

PATENT CLAIMS

1. Evaluation and control method of a multi-fuel burner for alternative fuels, which has a measuring and control arrangement (10), which

- an infrared camera (4) that corresponds to a burner mouth

(3) is assigned to the multi-fuel burner (1),

- a data processing unit (6),

- and has a regulation and control unit (7),

wherein the data processing unit (6) is operatively connected to the regulation and control unit (7) and the infrared camera (4),

comprehensive the steps

a) using the infrared camera

(4) recording a current burning image in the infrared spectral range during a burning process, the burning image showing image data of a recording section (A) which includes the burner mouth (3) and which contains substitute fuel particles (5),

b) sending the image data of the burning image to the data processing unit (6), c) using the data processing unit (6) to determine the substitute fuel particles (5) from the image data and determining the size and position of at least a majority of the particles (5),

d) determining current characteristic values from the data determined in step c).

Rronnnaramotor ι mrl \/ornloirhon Horcolhc-n with unmanaged Qnll Rronnnormotors,

e) if the current characteristic firing parameters deviate from the target firing parameters in the regulation and control unit (7) adjusting regulation and / or control parameters that correlate with the characteristic firing parameters, and thereby changing the characteristic firing parameters until the current characteristic firing parameters correspond to the target firing parameters,

f) continuously repeating the aforementioned steps a) to e). Method according to claim 1,

where in step c)

for determining substitute fuel particles (5) from image data of at least one image, at least one parameter from the group of temperature, intensity, speed magnitude, speed direction and probable position of a particle (5) is determined based on previously known temperature and/or probability and/or speed models.

Method according to claim 1 or 2,

where

the at least one characteristic combustion parameter is selected from the group position, size, distribution, average trajectory, time of combustion, distribution behavior and / or scattering behavior of the substitute fuel particles (5) in the combustion chamber (2).

Method according to at least one of claims 1 to 3,

comprehensive the step

c') further determining from the image data

- of agglomerations 5 'of the substitute fuel particles (5), and / or

- a probability of residence of the substitute fuel particles (5) in a combustion chamber (2) of the burner (1), and/or

- time of combustion of the substitute fuel particles (5) after leaving the burner mouth (3), and/or

- Determining an impact position and/or an impact time of the substitute fuel particles (5) in a solid bed (8) in the burner chamber (2), and/or

- a distribution of the substitute fuel particles

(5) during a flight phase.

Method according to at least one of claims 1 to 4,

where

in step e) at least one regulation and/or control parameter from the group of primary air quantity, secondary air quantity, pressure of a pneumatic deflector and/or twist of the air can be set for regulation and/or control on the burner (1).

6. Method according to at least one of claims 1 to 5,

comprehensive the step

e') Comparing current and stored specific burning parameters with predetermined target burning parameters, determining a burning behavior from this and evaluating the burning behavior according to predetermined criteria.

7. Evaluation and control arrangement (10) for carrying out the method according to at least one of claims 1 to 6,

characterized in that

- The arrangement (10) has a burner (1) with a burner mouth (3) and an infrared camera (4) for recording substitute fuel particles (5) in the infrared spectral range, the infrared camera (4) being arranged in front of the burner mouth (3). is that the burner mouth (3) and a flame (11) lie in front of the burner mouth (3) in the recording section (A) of the infrared camera (4), and

- That the arrangement (1) has a data processing unit (6) which is operatively connected to the infrared camera (4) and a regulation and control unit (7) of the burner (1).