U.S. patent application number 13/141109 was filed with the patent office on 2012-03-08 for method and device for optimizing combustion in a power plant.
Invention is credited to Bernhard Meerbeck, Rainer Speh.
Application Number | 20120058438 13/141109 |
Document ID | / |
Family ID | 40822953 |
Filed Date | 2012-03-08 |
United States Patent
Application |
20120058438 |
Kind Code |
A1 |
Meerbeck; Bernhard ; et
al. |
March 8, 2012 |
Method and Device for Optimizing Combustion in a Power Plant
Abstract
Methods and devices for optimizing combustion of fuel in a
combustion chamber of a power plant are provided. A real
concentration distribution of a material and/or a real temperature
distribution in the combustion chamber is measured in at least one
dimension. The real concentration distribution and/or temperature
distribution is evaluated and a combustion of fuel is controlled
such that a symmetric concentration distribution and/or temperature
distribution in the at least one dimension arises. During the
evaluation at least one characteristic of the symmetry of the real
concentration distribution and/or temperature distribution is
determined, and during the controlling at least one control
parameter is changed depending on the at least one
characteristic.
Inventors: |
Meerbeck; Bernhard;
(Kelkheim, DE) ; Speh; Rainer; (Weiterstadt,
DE) |
Family ID: |
40822953 |
Appl. No.: |
13/141109 |
Filed: |
December 21, 2009 |
PCT Filed: |
December 21, 2009 |
PCT NO: |
PCT/EP2009/067627 |
371 Date: |
November 17, 2011 |
Current U.S.
Class: |
431/12 ;
431/75 |
Current CPC
Class: |
F23N 2225/08 20200101;
F23N 1/022 20130101; F23N 5/003 20130101 |
Class at
Publication: |
431/12 ;
431/75 |
International
Class: |
F23N 1/02 20060101
F23N001/02; F23N 5/00 20060101 F23N005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2008 |
EP |
08172545.9 |
Claims
1.-8. (canceled)
9. A method of optimizing combustion of fuel in a combustion
chamber of a power plant, comprising: measuring a real
concentration distribution of a substance in the combustion chamber
in at least one dimension; evaluating the real concentration
distribution; controlling a combustion of fuel such that a
symmetric concentration distribution of the substance is created in
the at least one dimension; determining at least one characteristic
for a symmetry of the real concentration distribution during the
evaluating; and modifying at least one control parameter depending
on the at least one characteristic during the controlling.
10. The method as claimed in claim 9, wherein two-dimensional
concentration distributions are measured, and wherein at least one
one-dimensional concentration distribution is calculated there from
during the evaluating.
11. The method as claimed in claim 9, wherein the real
concentration distribution is decomposed into a plurality of
sections, and wherein the combustion is controlled such that a
symmetric concentration distribution is created in each
section.
12. The method as claimed in claim 10, wherein the real
concentration distribution is decomposed into a plurality of
sections, and wherein the combustion is controlled such that a
symmetric concentration distribution is created in each
section.
13. A method of optimizing combustion of fuel in a combustion
chamber of a power plant, comprising: measuring a real temperature
distribution in a combustion chamber in at least one dimension,
evaluating the real temperature distribution; controlling a
combustion of fuel such that a symmetric temperature distribution
is created in the at least one dimension; determining at least one
characteristic during the evaluating for a symmetry of the real
temperature distribution; and modifying a control parameter during
the controlling depending on the at least one characteristic.
14. The method as claimed in claim 13, wherein two-dimensional
temperature distributions are measured, and wherein at least one
one-dimensional temperature distribution is calculated there from
during the evaluating.
15. The method as claimed in claim 13, wherein the real temperature
distribution is decomposed into a plurality of sections, and
wherein the combustion is controlled such that a symmetric
temperature distribution is created in each section.
16. The method as claimed in claim 14, wherein the real temperature
distribution is decomposed into a plurality of sections, and
wherein the combustion is controlled such that a symmetric
temperature distribution is created in each section.
17. A device for optimizing combustion of fuel in a combustion
chamber of a power plant, comprising: a measuring device for
measuring a real distribution in a combustion chamber in at least
one dimension; an evaluation device for evaluating the real
distribution; a control device for controlling a combustion of fuel
such that a symmetric distribution is created in the at least one
dimension.
18. The device as claimed in claim 17, wherein the measuring device
measures a real concentration distribution of a substance in the
combustion chamber, the evaluation device evaluates the real
concentration distribution, and the control device controls the
combustion of fuel such that a symmetric concentration distribution
of the substance is created in the at least one dimension.
19. The device as claimed in claim 18, wherein two-dimensional
concentration distributions are measured, and wherein at least one
one-dimensional concentration distribution is calculated there
from.
20. The device as claimed in claim 18, wherein the real
concentration distribution is decomposed into a plurality of
sections, and wherein the combustion is controlled such that a
symmetric concentration distribution is created in each
section.
21. The device as claimed in claim 17, wherein the measuring
devices measures a real temperature distribution in the combustion
chamber; the evaluation device evaluates the real temperature
distribution; and the control device controls the combustion of the
fuel such that a symmetric temperature distribution is created in
the at least one dimension.
22. The device as claimed in claim 21, wherein two-dimensional
temperature distributions are measured, and wherein at least one
one-dimensional temperature distribution is calculated there
from.
23. The device as claimed in claim 21, wherein the real temperature
distribution is decomposed into a plurality of sections, and
wherein the combustion is controlled such that a symmetric
temperature distribution is created in each section.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International
Application No. PCT/EP2009/067627 filed Dec. 21, 2009, and claims
the benefit thereof. The International Application claims the
benefits of European Patent Application No. 08172545.9 DE filed
Dec. 22, 2008. All of the applications are incorporated by
reference herein in their entirety.
FIELD OF INVENTION
[0002] The invention relates to a method and a device for
optimizing the combustion of fuel in a combustion chamber of a
power plant, in which a real concentration distribution of a
substance and/or a real temperature distribution is measured in the
combustion chamber.
BACKGROUND OF INVENTION
[0003] It is the basic object in the case of power plants to
monitor the combustion, which occurs in a combustion chamber of the
power plant, for example a boiler with a square surface area of 10
meters by 10 meters, over the largest possible area in order to be
able to derive therefrom the necessary variables for optimizing the
combustion process.
[0004] For example, absorption spectroscopy is a known method.
Acoustic pyrometry is a known alternative measurement technique.
Absorption spectroscopy and acoustic pyrometry can only measure
mean values along a line through the boiler chamber or combustion
chamber.
[0005] The CAT (computer-aided tomography) measurement technique is
known for calculating the temperature- and concentration
distribution in a plane of a combustion chamber from measured mean
values at different locations of the combustion chamber of a power
plant.
SUMMARY OF INVENTION
[0006] It is an object of the invention to develop a further
optimization of the combustion in a power plant.
[0007] The object is achieved by methods and devices as claimed in
the independent claims. Advantageous developments are described in
the dependent claims.
[0008] The method for optimizing the combustion of fuel in a
combustion chamber of a power plant comprises the steps of:
measuring a real concentration distribution of a substance in the
combustion chamber in at least one dimension, evaluating the real
concentration distribution, and controlling the combustion of the
fuel such that a symmetric concentration distribution of the
substance is created in the at least one dimension.
[0009] Alternatively, or in addition thereto, the method for
optimizing the combustion of fuel in a combustion chamber of a
power plant comprises the steps of: measuring a real temperature
distribution in the combustion chamber in at least one dimension,
evaluating the real temperature distribution, and controlling the
combustion of the fuel such that a symmetric temperature
distribution is created in the at least one dimension.
[0010] More particularly, within the scope of the method, at least
one characteristic for the symmetry of the real concentration
distribution and/or temperature distribution is established during
the evaluation process and at least one control parameter is
modified depending on the at least one characteristic during the
control process.
[0011] Accordingly, a device for optimizing the combustion of fuel
in a combustion chamber of a power plant comprises an apparatus for
measuring a real concentration distribution of a substance in the
combustion chamber in at least one dimension, an apparatus for
evaluating the real concentration distribution, and an apparatus
for controlling the combustion of the fuel such that a symmetric
concentration distribution of the substance is created in the at
least one dimension.
[0012] Alternatively, or in addition thereto, a device for
optimizing the combustion of fuel in a combustion chamber of a
power plant comprises an apparatus for measuring a real temperature
distribution in the combustion chamber in at least one dimension,
an apparatus for evaluating the real temperature distribution, and
an apparatus for controlling the combustion of the fuel such that a
symmetric temperature distribution is created in the at least one
dimension.
[0013] In the case of a first advantageous development of the
method, two-dimensional concentration distributions and/or
temperature distributions are measured during the measurement
process and at least one one-dimensional concentration distribution
or temperature distribution is calculated therefrom during the
evaluation process.
[0014] In the case of a further advantageous development of the
method, the real concentration distribution and/or temperature
distribution is decomposed into a number of sections during the
evaluation process and the combustion is controlled such that a
symmetric concentration distribution or temperature distribution is
created in each section.
[0015] In other words, an at least one-dimensional, but preferably
two-dimensional, distribution of the temperature and/or
concentration of at least one substance is generated on the basis
of known measurement techniques. The distribution measured thus is
used to calculate one-dimensional and mathematical distributions or
curves along an axis or along an axis section. Characteristics are
preferably established for the distributions, which characteristics
ascertain or describe the symmetry or asymmetry (skewness) of the
mathematical distribution. Depending on the characteristics,
suitable regulating units, such as e.g. metering hoppers for coal
or air-control flaps, are trimmed such that there is a symmetric
distribution along each axis. If there are a number of mathematical
distributions along one axis, the observed axes are subdivided into
suitable axis sections and the above-described optimization is then
performed for each of the sections.
[0016] The described procedure and the associated device allow a
largely homogeneous and hence low-pollutant combustion with
automatic adaptation of the regulating parameters.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In the following text, an exemplary embodiment is explained
in more detail on the basis of the attached schematic drawings, in
which:
[0018] FIG. 1 shows an exemplary embodiment of the device,
[0019] FIG. 2 shows an exemplary embodiment of the method, and
[0020] FIG. 3 shows, by means of grayscale values, graphs of the
distributions of CO and O.sub.2 in a measurement plane of the
device as per FIG. 1 before and after an optimization.
DETAILED DESCRIPTION OF INVENTION
[0021] FIG. 1 illustrates a combustion chamber 10 of a coal power
plant (not illustrated in any more detail), in which a coal fire
burns during operation of the coal power plant. Here, the
combustion chamber 10 contains fuel--coal--together with associated
fuel gases, flames 11 and exhaust gases.
[0022] Two measurement planes 12 and 14 are provided in the
combustion chamber 10, on the edge of which planes there are
measurement instruments 16, which are respectively spaced apart
from one another. Two measurement instruments 16 in each case allow
a measurement along a line in the associated measurement plane 12
and/or 14, wherein e.g. the concentration of the substances O.sub.2
(oxygen) and CO (carbon monoxide) can be measured with the aid of
the measurement instruments 16 and an associated evaluation
apparatus 18.
[0023] Furthermore, the measurement instruments 16 and the
evaluation apparatus 18 can be used to establish the temperature
distribution in the associated measurement plane 12 and/or 14. The
measurement in this case is based on a combination of measurement
technique and CAT calculation.
[0024] Via a data bus 20, the evaluation apparatus 18 is
operationally coupled to an optimization apparatus 22, an operating
apparatus 24, and a control apparatus or control and protection
system 26. The real concentration distributions and temperature
distributions established by the evaluation apparatus 18 are used
via the operating apparatus 24 such that the optimization apparatus
22 is used to generate suggestions for optimizing the combustion
and these suggestions can be used in the control apparatus 26. This
optimizes the flames 11 burning in the combustion chamber 10, in
particular in respect of low emission of NO.sub.x(nitrogen
oxide).
[0025] For the purposes of optimization, the optimization apparatus
22 evaluates the measured, real concentration distributions and
controls the combustion such that a symmetric concentration
distribution of the oxygen and carbon monoxide substances is
generated along at least one axis or in at least one dimension.
[0026] The associated method is illustrated in FIG. 2. It comprises
the step 28 of measuring the concentration distribution of at least
the O.sub.2 and CO substances in the aforementioned measurement
planes 12 and 14. In step 30, the temperature distribution is
established in these planes.
[0027] This input data is used in step 32 to evaluate
one-dimensional and mathematical distributions or curves, as well
as associated characteristics for the symmetry or asymmetry of the
distributions, from the concentration distributions. Furthermore,
the distributions or curves are decomposed into a number of
sections with their own, associated distributions in step 32.
[0028] Subsequently, on the basis of these investigations, an
optimization of the combustion is carried out in step 34 to the
effect that symmetric concentration- and temperature distributions
are created. These can be monitored in the measurement planes 14
and 16, and so overall this creates a closed-loop control circuit
to the step 28.
[0029] Although the measurement as per steps 28 and 30 could
evaluate thousands of features or items of information relating to
the combustion, it is deliberately only a very small section or
part of this information that is processed in the described
procedure. Otherwise it would not be possible to achieve an
expedient cost/use ratio.
[0030] The evaluation is carried out on the basis of three basic
assumptions or three basic simplifications: only direct measurement
values, moments, and gradients of the measurements are utilized.
Thus, in particular, the distribution tomography of the measured
concentrations and temperatures is reconstructed on the basis of,
in particular, 20 to 25 points of intersection of the measurements.
These direct measurement values are described as feature vectors.
Furthermore, the underlying difference values between these direct
measurement values are used and, if desired, intermediate values
can be established on the basis of interpolation.
[0031] In order to obtain distributions in each desired direction,
the first to fourth moment are established along the horizontal,
the vertical, and both diagonals of each measurement field, i.e. of
each field between the points of intersection. The moments are
established on the basis of the profiles or distributions along
each measurement direction or dimension. The first and second
moment represent the mean value and the variance of a distribution.
The third and fourth moment represent the skewness and kurtosis of
a distribution. The skewness is a measure of symmetry or lack of
symmetry. The kurtosis is a measure of whether the distribution is
peaked or shallow compared to a normal distribution or Gaussian
distribution.
[0032] Furthermore, the gradient of the mean value is established
in each measurement field. The magnitude or value of the gradient
provides information (e.g. illustrated as an arrow in the
respective measurement field) as to where peaks or concentrations
are located in the distribution. FIG. 3 shows the result of the
optimization of the combustion undertaken thus. FIG. 3 clearly
shows the largely symmetric distribution of CO and O.sub.2 in the
measurement plane 12 after the optimization.
* * * * *