DE102016000290A1 - Evaluation and control method for multi-fuel burners and evaluation and control arrangement for it - Google Patents

Abstract

The present invention provides an evaluation and control arrangement as well as an evaluation and control method of a multi-fuel burner for alternative fuels. The multi-fuel burner (1) has a measuring and control arrangement (10) which has an infrared camera (4) which is assigned to a burner mouth (3) of the multi-fuel burner (2), a data processing unit (6) and a regulation and control unit (7 ), wherein the data processing unit (6) with the control and control unit (7) and the infrared camera (4) is operatively connected. By means of the infrared camera (4), a current focal image is recorded in the infrared spectral range during a firing process, wherein the focal image image data of a receiving section (A), which includes the burner mouth (3) and the substitute fuel particles (5) shows. These substitute fuel particles (5) are determined from the image data with the aid of a data processing unit (6), and current characteristic firing parameters are determined. The same are compared with predetermined nominal combustion parameters. If the current characteristic combustion parameters deviate from the desired combustion parameters, control and / or control parameters in the control and regulation unit (7) are adapted.

Description

The invention relates to an evaluation and control method for multi-fuel burner and 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 the clinker takes place using 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, incompletely burned fuel ends up directly in the reaction area of the raw materials during this manufacturing process and 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 object is achieved by an evaluation and control method having the features of claim 1 and by the corresponding evaluation and control arrangement having the features of independent claim 7.

Further developments or preferred embodiments of the evaluation and control method and 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 or all of the particles determined.

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), if the current characteristic firing parameters deviate from the desired firing parameters in the control and regulation unit, the control and / or control parameters that correlate with the characteristic firing parameters are adjusted, thereby changing the characteristic firing parameters until the current characteristic firing parameters Combustion parameters correspond to the nominal combustion 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, a combustion of substitute fuel can be extensively monitored, measured and evaluated and used to assess 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 by the method according to the invention so that the burning behavior of substitute fuels can be better understood and the proportion in a firing process can be significantly increased.

"Burning parameters" or combustion parameters in the sense of the invention are all image-based parameters which can be recorded from the image data or the recording by the infrared camera or determined by the subsequent evaluation. The combustion parameters describe the state or can map the state of combustion currently and over a certain period of 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 in a sustainable manner.

The invention relates to an evaluation and control method, wherein a pilot control can be included with respect to the fuel composition.

"Adjusting the firing parameters" in the sense of the invention means that the firing parameters can be approximated to target specifications. They therefore form dynamic values that constantly change and, ideally, approach target values. The term "current" is always to be seen at a certain time, and changes over time or adapts itself. 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 any ignition and combustion process as well as any escape 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 camera image 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 may 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, velocity direction and probable position of a particle due to 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 image contrasting image processing methods are first applied to a single image and a reduction to a region of interest takes place in which, for example, a majority of the particles are statistically assumed becomes.

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. 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 property specifications are not met, the region is removed from the segmentation. Furthermore, it is possible to perform temporal filtering of the image data (eg temporal mean value filters) in order to delimit image areas with fuel from other image areas more clearly. 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 extractor can be carried out. 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. On the basis of these distributions, it is then possible to calculate, inter alia, the mean trajectory of the fuel and the distribution behavior or scattering behavior of the fuel in the flight phase.

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. Preferably, these manipulated variables can influence the firing process; for suitable settings u. a. Empirical values used.

In addition to monitoring and regulating the firing process, the invention can provide that based on 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 at certain areas in the oven or a desired flight behavior or a combustion time can be 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. Also the The combustion time of the particles can be determined. It is possible to look at the alternative fuel content and thus assess 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 impact 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 comprises 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 such that the burner mouth and a flame in front of the burner mouth in the receiving portion of the infrared camera. 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 exit and flight behavior of alternative fuels in industrial multi-fuel burners based on recordings of infrared cameras can be analyzed by the invention, since this type of evaluation and control arrangement can capture a Brennprozesszustand by using the inventive method in a timely manner.

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 drawings. 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 a schematic view of a monitoring arrangement according to the invention,

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

3 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 a photographic view of an image-processed photograph,

6 a processed photographic image with detected particles, and

7 a graph showing the distribution of the particles.

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

In 2 is the recording area A of the infrared camera 4 shown schematically, with a flame 11 from the Brenner mouth 3 in the combustion chamber 2 extends into it. Within this flame 11 lie substitute fuel particles 5 ago, in a specific trajectory F from the Brenner mouth 3 Be carried out. After a certain time, which depends on the nature and material of the 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 8th ,

In 3 is an exemplary distribution of the substitute fuel particles 5 shown schematically, wherein the particles 5 within a jet trajectory F with a mean trajectory F 'from the burner mouth 3 out into the burner room 2 fly. The particles 5 can move alone or agglomerations 5 ' form. Furthermore, they form at the Brenner mouth 3 Carbon regions K. The multi-fuel burner shown 1 for example, has two fuel feeds. A centrally located in the burner mouth supply for the substitute fuel. Another fuel supply is located coaxially around the center Replacement fuel feeder and serves as a feeder for the standard fuel coal. Two feeds are necessary as coal and substitute fuels 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, if 100% substitute fuel is used, there is no coal area K. 3 shows a scheme of combustion with a certain proportion of coal, so that the coal regions K form.

The 4a to 4f show photographic shots of an infrared camera 4 for different settings of the burner 1 , From the Brenner mouth 3 the flame extends 11 in the burner room 2 into which the particles are 5 are located. In the infrared images, the particles show up 5 in dark, almost black gray; the flame 11 is seen around there in medium gray.

The six photographic frames of the 4a to 4f represent a consequence of an ongoing burning process, being at the burner 1 Various presets have been made that 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 Pneumodeflektors in mbar and a twisting (also called "swirl"). The twisting or air turbulence is unitless and refers in the following numerical example to a setting on the burner 1 and may 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 be used to influence and focus a particle beam in its trajectory. FIG. EBS [%] Pressure Pneumodeflector [mbar] swirl 4a 60 40 2 4b 65 40 4 4c 100 40 4 4d 60 40 8th 4e 65 200 4 4f 100 200 4

By means of an imaging process, which 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 can 5 themselves (which are represented as small crosses) can be detected, such as 5 shows a photographic photograph of the recording area for an exemplary burner setting. From the position and size of the particles 5 can calculate a distribution, from which their trajectory F and also a middle trajectory 5 ' can be determined. In addition, the maximum exit angle W of the total fuel at Brennermund can also 3 (in 5 by means of two lines W left and right of the burner mouth 3 shown). The drawn rectangle indicates a region of interest R, which is limited in the image analysis, whereby in this area after the particles 5 "Searched" and analyzed.

The 6 shows an already processed image that makes it possible to take a look at the alternative fuel fraction (particle 5 ) and an assessment of their scattering behavior. Based on this picture z. B. individual particles 5 be detected. Here, only the area in front of the burner mouth 3 , ie in a realistic flight range of the fuel, considered.

If these particle detections are observed over a longer period of time, a kind of hit list can be created, as in 7 to see. The particles 5 are determined and their properties, such as size, position and distribution can be computationally further processed, as in 7 shown. The individual particle detections of substitute 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 region of interest or "region of interest". 7 shows an excerpt from such an area of interest and the Gaussian estimates (lines G) of selected estimates within the region of interest R corresponding to the associated averages and above and below the 1σ 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 getting closed.

For camera-based recording of the exit and flight behavior of replacement fuel particles of an industrial multi-fuel burner 1 as well as its regulation and control can by means of the infrared camera 4 and with the aid of an imaging method, the substitute fuel particles 5 be detected.

Based on the calculated image-based characteristics of the substitute fuel particles 5 , characteristics can be determined, which are used to characterize the exit-flight behavior of the particles 5 suitable. These characteristics can hereafter readily in the regulation of the multi-fuel burner 1 Find input and from the control unit 7 be implemented.

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 image components that also reflect in the infrared spectrum, such as particles 5 or other solids and their behavior in the combustion chamber 2 monitored and evaluated.

LIST OF REFERENCE NUMBERS

1

Multifuel

2

combustion chamber

3

burner mouth

4

Infrared camera

5

Waste-to-particle

5 '

agglomerations

6

Data processing unit

6a

Storage

7

Control and regulation unit

8th

Solid bed

9

data lines

10

supervision order

11

flame

A

receiving portion

F

trajectory

F '

Medium trajectory

K

coal sector

R

Region of interest

G

Line of Gauss estimate

W

exit angle

Claims (7)

Evaluation and control method of a multi-fuel burner for alternative fuels, comprising a measurement and control arrangement ( 10 ), which - an infrared camera ( 4 ), which corresponds to a burner mouth ( 3 ) of the multi-fuel burner ( 1 ), - a data processing unit ( 6 ), - and a control and regulation unit ( 7 ), wherein the data processing unit ( 6 ) with the control and regulation unit ( 7 ) and the infrared camera ( 4 ) is operatively connected, comprising the steps a) by means of the infrared camera ( 4 during a firing process recording a current focal image in the infrared spectral range, wherein the focal image image data of a receiving section (A), the burner mouth ( 3 ) and the substitute fuel particle ( 5 ), b) sending the image data of the focal image to the data processing unit ( 6 ), c) by means of the data processing unit ( 6 ) from the image data determining the substitute fuel particles ( 5 ) and determining the size and position of at least a majority of the particles ( 5 d) from the data determined in step c) determining current characteristic combustion parameters and comparing them with predetermined desired combustion parameters, e) when the current characteristic combustion parameters deviate from the desired combustion parameters in the control and regulation unit ( 7 ) Adjusting control 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) through e). The method of claim 1, wherein 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 amount, velocity direction and probable position of a particle ( 5 ) is determined on the basis of previously known temperature and / or probability and / or speed models The method of claim 1 or 2, wherein the at least one characteristic firing parameter from the group position, size, distribution, average trajectory, combustion timing, distribution behavior and / or scattering behavior of the substitute fuel particles ( 5 ) in the combustion chamber ( 2 ) is selected. Method according to at least one of claims 1 to 3, comprising the step c ') from the image data further determining - agglomerations 5 ' the substitute fuel particle ( 5 ), and / or - a probability of residence of the substitute fuel particles ( 5 ) in a combustion chamber ( 2 ) of the burner ( 1 ), and or - Combustion time 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 replacement fuel particles ( 5 ) in a solid bed ( 8th ) in the burner room ( 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, wherein in step e) for a regulation and / or control on the burner ( 1 ) at least one control and / or control parameter from the group of primary air quantity, secondary air quantity, pressure of a pneumodeflector and / or twisting of the air is adjustable. Method according to at least one of claims 1 to 5, comprising the step e ') comparing current and stored specific combustion parameters with predetermined target combustion parameters, determining therefrom a combustion behavior and evaluating the combustion behavior according to predetermined criteria. Evaluation and control arrangement ( 10 ) for performing the method according to at least one of claims 1 to 6, characterized in that - the arrangement ( 10 ) a burner ( 1 ) with a burner mouth ( 3 ) and an infrared camera ( 4 ) for receiving substitute fuel particles ( 5 ) in the infrared spectral range, wherein the infrared camera ( 4 ) so in front of the burner mouth ( 3 ), that the burner mouth ( 3 ) and a flame ( 11 ) in front of the burner mouth ( 3 ) in the receiving section (A) of the infrared camera ( 4 ), and - that the arrangement ( 1 ) a data processing unit ( 6 ) operating with the infrared camera ( 4 ) and a control and control unit ( 7 ) of the burner ( 1 ) connected is.

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