JP2013044018A - Method for evaluating solid fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation method, regarding generated NOx in a sintered ore production process for a blast furnace feed, in which the frequency of combustion experiments causing a high cost and a high load can be reduced, and the simplification in the evaluation of the quantity of the generated NOx in a fuel is achieved.SOLUTION: Regarding generated NOx in an iron ore sintered ore production process utilizing the combustion heat of a high heat generation solid fuel essentially consisting of surface combustion, nitrogen in the fuel is subjected to chemical structure analysis, the ratio of a plurality of nitrogen chemical structure seeds contained therein is determined, and the ratio is compared with the quantity of the generated NOx on the combustion, thus the relation between each nitrogen chemical structure seed ratio and quantity of the generated NOx is estimated, and whether the quantity of the generated NOx is large or not can be estimated by the nitrogen chemical structure analysis in coal.

Description

  The present invention relates to a method for evaluating a solid fuel more simply by estimating the amount of nitrogen oxide generated in the production process of a blast furnace raw material sintered ore from the nitrogen chemical structure in the solid fuel.

  In an integrated steelworks with a blast furnace, the most important item is the stable production of cheap and high-quality pig iron. The main raw material of the blast furnace producing pig iron is iron ore. Iron ore is generally classified into massive ore (> 5 mm) and fine ore (≦ 5 mm) according to particle size. Usually, fine ore is cheaper than lump ore. However, when the powder ore is directly charged into the blast furnace, the furnace is densely filled. As a result, the blowing of hot air from below, which is essential in blast furnace operation, is obstructed and the continuous reduction reaction is delayed, making it difficult to produce stable pig iron.

Therefore, a raw material pretreatment method is generally performed in which the powdered ore is baked and hardened with heat of about 1200 ° C. to 1400 ° C., and sintered ore having a particle size of a certain size or more is produced in advance (hereinafter referred to as “raw material pretreatment method”) The production of sintered ore by this method is referred to as “sintered ore production” as necessary).
In general, iron ore as the main raw material, lime / silica sand as a secondary raw material, and fuel as a heat source are mixed at a fixed ratio, and water or the like as a binder is added to these mixtures, and a rotating drum or the like. The granulated material is used as a sintering raw material. The sintered raw material is laid on a sintering machine, and then the fuel contained in the upper sintered raw material is ignited by a burner or the like. The combustion heat of the fuel is transferred by air suction from below, and sequentially ignites the fuel. Thereby, heat propagation occurs in the sintered raw material, and the entire sintered raw material is sintered. The manufacture of sintered ore by the internal heat downward suction method by the combustion heat of the fuel embedded in the sintered raw material and the suction of air from below the sintered raw material is the manufacture of the sintered ore for blast furnace So it is common.

  The most important performance required for sintered ore is that the sintered ore has strength that does not pulverize when it is transported to the blast furnace and dropped. In order to increase the strength of the sinter, it is generally known that sinter production at a higher temperature is effective (see Non-Patent Document 1). Therefore, the fuel used for sinter production is usually a solid fuel with a higher calorific value. Among these solid fuels, coal volatiles and anthracite with a low volatile content are selected as fuels used for the production of sintered ore (in the following explanation, this coal pulverized matter is referred to as “coke” as necessary. Called).

  Coal, which is a more general solid fuel, has a certain amount of volatile components, and its combustion is cracked combustion in which combustible gas generated by thermal decomposition by ignition heat burns. On the other hand, coke and anthracite have extremely few volatile components, and the combustion is classified as a phenomenon of surface combustion. Since this surface combustion cannot obtain a calorific value by thermal decomposition, a high calorific value is generally obtained. However, the fuel that causes surface combustion has limited industrial applications compared to coal, such as high temperature required for ignition and difficulty in continuous combustion and complete combustion.

On the other hand, the amount of nitrogen oxides generated during the production of sintered ore (in the following explanation, nitrogen oxides are referred to as “NOx” as necessary) accounts for half of the total amount of NOx generated in the integrated steelworks (non- (See Patent Document 2). NOx is regulated by various laws and regulations, and it is required to further reduce the amount of NOx generated in order to reduce the environmental load.
There are two types of NOx generation during combustion (see Non-Patent Document 3). First, there is NOx generated on the basis of nitrogen in the atmosphere in a higher-temperature combustion process exceeding 1500 ° C. (in the following description, this NOx is referred to as “Thermal NOx” as necessary). . Secondly, there is NOx originating from nitrogen in fuel, which accounts for most of NOx generated during combustion at 1400 ° C. or lower (hereinafter referred to as “Fuel NOx” as necessary). Denitration equipment has been installed as a measure to control Thermal NOx in high-temperature process equipment that is generated at a high concentration in a shorter time, but many equipment without denitration equipment is installed in low-temperature process equipment (non-patented) (Ref. 4). For thermal NOx in a high temperature process that is relatively problematic, it is proactive to reduce the amount of generation itself through combustion analysis and the development of a low NOx burner associated therewith (see Non-Patent Document 5). Although measures have been taken, there has been no method for Fuel NOx other than using a fuel containing lower nitrogen (see Patent Document 1).

  In the sintered ore manufacturing process, which is a problem in the steel industry, solid fuel with a high calorific value is used, but most of the generated heat is used for heating the sintering raw material. For this reason, as a whole process, the combustion process same as the combustion process at 1200 ° C. to 1400 ° C. is also a low-temperature process, and Fuel NOx is attributed to generation of NOx (see Non-Patent Document 6).

Recently, research has been conducted focusing on the chemical structure of nitrogen in coal and the relationship between the generated gas species and NOx during high-speed carbonization (see Non-Patent Document 7), and the amount of generated NOx has been estimated. It has been broken. However, the generation of NH ₃ and HCN (VM N), which are volatile nitrogen species, assuming cracking and combustion among the nitrogen that is the origin of Fuel NOx, and their route to NOx or N ₂ are predicted. As for the combustion of nitrogen called char nitrogen (Char N) which is less likely to volatilize and assumes surface combustion, the amount of NOx generated from solid fuel has not been estimated.

  In the sinter production process, surface combustion is the center. Therefore, in order to clarify the phenomenon of NOx conversion during combustion, a method for determining and evaluating the correlation with char nitrogen is necessary. In addition, efforts related to the relationship between the chemical structure of nitrogen and NOx are not accompanied by combustion experiments, and the correlation with the amount of NOx actually generated from solid fuel is not always clear, regardless of VM N or Char N. It was not.

Therefore, although the generation of NOx from coal-based plants and facilities can be predicted to some extent, the amount of NOx generated from fuel with low volatile content (for example, a process for obtaining heat by burning char such as anthracite or coke, That is, it was impossible to predict the amount of NOx generated in the sinter ore production process for blast furnace raw materials in the steel industry.
In addition, evaluation of solid fuel, in which the amount of generated NOx is measured by changing the type of solid fuel, regardless of the prediction of the chemical structure or the like, is performed in a department that uses each combustion process. However, in general, it is necessary to prepare a certain amount or more of fuel in order to perform combustion experiments as well as evaluation with actual machines. If such a large-scale experiment is performed, both the actual machine and the combustion experiment become expensive. Moreover, the change of the fuel in a short period becomes a high load in a continuous process, for example. Furthermore, when coal dry distillate is a target, there are a great variety of coal as the raw material. For this reason, it is not realistic to perform all fuel combustion experiments, and a fuel evaluation method that can minimize the combustion experiments has been demanded.

JP 2005-290456 A

Steel Handbook 4th edition, Japan Iron and Steel Association Inagatsu Tadahiro, Series “Steel Technology Flow 2nd Series”, Volume 1, Sinter, (2000) Supervised by Norio Arai, edited by Takatoshi Miura, Generation and suppression technology of combustion products, (1997) Edited by Project News, present status of flue gas desulfurization and denitration equipment IV, (2001) Naoki Makino and two others, Thermal Power Generation, 48 (6) (1997), p702 Masahiro Hida, Iron and Steel, Vol. 68, (1982), p400 S. Kambara, Fuel, 75 (1995), p1247

  The object of the present invention is to estimate the amount of NOx generated from nitrogen (Char N), which is difficult to volatilize, among NOx generated during combustion of solid fuel used in the production of sintered ore for blast furnace raw materials. To estimate the amount of NOx generated from solid fuel during the production of sintered ore using the estimated chemical formula analysis and the result of the minimum combustion experiment Is to propose.

The present inventors conducted various studies in order to propose a method for evaluating low NOx fuel in sinter production. As a result, estimation of the nitrogen chemical structure in coal and the ratio of nitrogen oxides (NOx) generated from solid fuel can be performed more easily by determining the evaluation formula with fewer combustion experiments. An evaluation method having the following characteristics (1) to (6) was developed.
The gist of the present invention is as follows (1) to (6).
(1) A solid fuel evaluation method for estimating the amount of nitrogen oxides generated from solid fuel during the production of sintered ore for blast furnace raw material, and analyzing the nitrogen chemical structure of multiple types of standard fuel and the solid fuel Performing a structural ratio derivation step for obtaining a structural ratio of various nitrogen chemical structural species in each of the plurality of types of standard fuel and the solid fuel, and performing a combustion experiment on the plurality of types of standard fuel, A process for deriving the amount of nitrogen oxides generated from the plurality of types of standard fuel, the amount of nitrogen oxides generated in the plurality of types of standard fuel, and the nitrogen chemistry in the types of standard fuel An estimation formula deriving step for obtaining an estimation formula for estimating the generation amount of nitrogen oxides in a solid fuel having an arbitrary structural ratio using the structural ratio of the structural species, and the nitrogen chemical structural species in the solid fuel Solid fuel evaluation method characterized by having a nitrogen oxide generation amount estimation step of estimating the generation amount of nitrogen oxide generated from the solid fuel from forming a ratio using the estimated equation.
(2) The nitrogen oxide generation amount derivation step performs a combustion experiment of the standard fuel as many times as the number of nitrogen chemical structural species in the solid fuel, in which the structural ratio is obtained in the structural ratio derivation step. The estimation formula deriving step uses the generation amount of nitrogen oxides of the standard fuel obtained in each of the standard fuel combustion experiments and the structure ratio of nitrogen chemical structural species in the plurality of types of standard fuels. The solid fuel evaluation method according to (1), wherein an estimation formula is obtained.
(3) The estimation formula is a formula for deriving a value obtained by multiplying the nitrogen amount in the solid fuel by the nitrogen structure index as an estimated value of the generation amount of nitrogen oxide in the solid fuel, and the nitrogen structure index is The nitrogen structure index corresponding to the ratio of nitrogen contained in the solid fuel to nitrogen oxides during the combustion of the solid fuel, the structure ratio of the nitrogen chemical structural species and the weighting parameter of the structure ratio of the nitrogen chemical structural species The solid fuel evaluation method according to (1) or (2), wherein the index is a nitrogen structure index expressed by a linear combination formula of
(4) The estimation formula deriving step includes a step of measuring the nitrogen concentration of the standard fuel and the nitrogen concentration of the solid fuel, and multiplying the nitrogen structure index by the amount of nitrogen in the solid fuel obtained from the nitrogen concentration. And setting a simultaneous equation by assuming that the value is equal to the amount of nitrogen oxide generated in the combustion experiment of the standard fuel, and determining the weighted parameter from the simultaneous equation ( The solid fuel evaluation method as described in 3).
(5) The step of deriving the structural ratio includes a nitrogen 1s orbital XPS spectrum obtained by performing a nitrogen chemical structure analysis on the plural types of standard fuel and the solid fuel by an XPS (X-ray Photoelectron Spectroscopy) method. Five peaks centered at 398.6 eV to 399.0 eV, 400.0 eV to 400.4 eV, 401.2 eV to 401.6 eV, 402.3 eV to 402.7 eV, and 403.6 eV to 404.0 eV The region having the various nitrogen chemical structural species, the ratio of the area of the region having each peak to the total area of the regions having all the peaks, and the structural ratio of the various nitrogen chemical structural species The solid fuel evaluation method according to any one of (1) to (4), wherein:
(6) The solid fuel evaluation method according to any one of (1) to (5), wherein the solid fuel is a coal distillate or anthracite having a volatile content of 10% by mass or less.

  By using the solid fuel evaluation method of the present invention, among the NOx generated during the combustion of the solid fuel used for the production of sintered ore for blast furnace raw material, it originates from nitrogen (Char N) that is hard to volatilize in the fuel. An estimation formula for estimating the amount of NOx generated is constructed using nitrogen chemical structure analysis and the result of the minimum combustion experiment, and the constructed estimation formula is used to estimate the NOx generated from solid fuel during the production of sintered ore. It is possible to evaluate the generation amount at a lower cost and a lower load.

It is a figure which shows an example of the XPS spectrum of nitrogen chemical structural species. It is a figure which shows the relationship between the NOx generation amount (NOx generation amount) obtained from the combustion experiment and the estimated value of NOx generation amount calculated from the structure index (structure index × nitrogen concentration) for each coke.

  The procedure of one embodiment of the low NOx solid fuel evaluation method will be described below. In the present embodiment, as an example of solid fuel, coal and its dry distillation product will be described as representatives. Further, in the present embodiment, a case where the generation amount of NOx generated from solid fuel is estimated by performing a nitrogen chemical structure analysis and a combustion experiment will be described as an example. However, the type of solid fuel, each experiment, and the analysis method are not limited to the methods described below.

First, the chemical structure analysis of nitrogen in solid fuel will be described.
First, among the solid fuels mainly used in the target combustion process, the most representative one is prepared and used as a standard sample. The solid fuel is, for example, a coal dry fraction or anthracite having a small volatile content (a volatile content is 10% by mass or less).
Subsequently, the nitrogen chemical structure analysis of the standard sample and the target sample is performed. The specific method for analyzing the chemical structure of nitrogen is not limited, but as a method for analyzing the chemical structure of nitrogen in solids, XPS (X-ray Photoelectron Spectroscopy) or NMR (Nuclear Magnetic Resonance) ) Method is typical. Here, a case where the XPS method is used as a method for analyzing nitrogen chemical structure will be described as an example.

First, each sample (standard sample and target sample) is powdered.
Next, each powdered sample is pressure-bonded onto a clean substrate made of In or the like, or pelletized so that each powdered sample does not scatter in the vacuum chamber used for XPS measurement. Perform pre-processing.

  Next, XPS measurement of the N1s orbit is performed according to the operation method of the apparatus to be used. At this time, simultaneously measuring the C1s orbital is effective for correcting chemical shift and estimating the N concentration in the solid fuel. Moreover, the ratio of nitrogen in the solid fuel is about 1-2% by mass, and the nitrogen in the solid fuel has a relatively low concentration. For this reason, in order to obtain spectrum data having a good S / N ratio, integration is required. However, a sample that is an organic substance may be broken by X-rays irradiated on the sample. For this reason, it is necessary to make the measurement in a short time or to measure with low energy. The present inventors have confirmed that the destruction of the sample does not occur even when measuring for a long time by setting the current voltage value of the X-ray source to a relatively low energy of about 10 A and 15 kV.

  The spectral data of each sample obtained by the above XPS measurement can be used as it is. However, it is effective to specify a chemical structure of nitrogen by performing general peak splitting on the spectrum data. In addition, already reported data can be used for chemical shift values and peak widths used for peak division. However, it is also effective to confirm the chemical shift value from the measurement result of a standard substance in each apparatus. Furthermore, it is also possible to estimate the chemical shift value using general quantum chemical calculations assuming chemical structural species. The present inventors have confirmed that a chemical shift value can be obtained in the form of a difference with respect to pyridine, which is a standard nitrogen chemical structural species, by Gaussian, a commercially available quantum chemical calculation software.

  FIG. 1 is a diagram showing an example of an XPS spectrum (photoelectron spectrum) of a nitrogen chemical structural species. The present inventors changed the spectrum 101 having a peak centered at 398.6 eV to 399.0 eV into a nitrogen-containing six-membered ring structure, 400.0 to 400.4 eV from the spectrum of nitrogen 1s orbital by peak splitting. The spectrum 102 having a peak centered at a nitrogen-containing five-membered ring structure, the spectrum 103 having a peak centered at 401.2 eV to 401.6 eV is a quaternary amine structure, 402.3 eV to 402.7 eV and 403. The spectra 104 and 105 having peaks centered at 6 eV to 404.0 eV are estimated as other structures, and the nitrogen structure is determined from the ratio of the area of each region having each peak to the sum of the area values of all regions having the peak. It has been confirmed that it is effective to determine the ratio. In FIG. 1, the regions of the spectra 101 and 104 (regions having peaks centered at 398.6 eV to 399.0 eV, regions having peaks centered at 402.3 eV to 402.7 eV) are indicated by hatching. Yes. Thus, each spectrum region (region having a peak) is a region surrounded by the base line for the region and the spectrum. The baseline for the regions of the spectra 101 and 104 is a broken line shown in FIG.

  Second, a combustion experiment is performed on a standard sample in which the chemical structure species of nitrogen is determined by the above method, and data relating to the amount of NOx generated from the standard sample is acquired. Although the specific method of the combustion experiment is not questioned, it is desirable to obtain actual data by an actual sintering machine test. When it is difficult to obtain actual data by the actual sintering machine test, data is obtained by performing a sinter ore production simulation experiment that reproduces the actual combustion field as much as possible. When performing a sinter ore production simulation experiment, it is essential that at least the combustion temperature be comparable to that of the actual sintering machine test. As a sinter production simulation experiment, a sintering pot test using a sample of kilogram order is common. However, an experiment with a smaller amount of sample or a gram order laboratory experiment is also effective if the sintering combustion phenomenon generated by the suction of air from below is simulated. In addition, it is effective to simulate coexisting substances and oxygen concentration during combustion. Furthermore, it is desirable to use actual machine test results if possible.

Subsequently, it is necessary to quantify the amount of NOx generated from the solid fuel from the result of the combustion experiment. The most effective method for quantifying the amount of NOx generated from the solid fuel is to determine the total amount of NOx generated from the solid fuel with respect to the amount of solid fuel input. There is no limitation on the specific method for quantifying the amount of NOx generated. The present inventors can measure NO, NO ₂ , and N ₂ O, which are typical NOx gases generated during combustion, by a continuous gas measurement using a general infrared spectroscopy, and are effective. I have confirmed that.

  In order to determine the amount of NOx generated, first, the intensity and position of a peak corresponding to NOx are confirmed by measuring the NOx sample gas having a known concentration by infrared spectroscopy. Thereafter, the gas generated during the combustion experiment is continuously introduced into the infrared spectrometer, and the spectrum of the gas is measured. After completion of the combustion experiment, it is possible to define the total gas generation amount by defining the concentration of the generated gas from the peak intensity of the measured spectrum and multiplying this by the gas generation time. At this time, it is possible to simultaneously measure the amount of gas introduced into the infrared spectroscopic device and the fluctuation of the pressure, and use these measured values to improve the accuracy of the total amount of gas generated. . In addition, the present inventors have confirmed that measuring the total amount of gas generated by a general gas chromatography method is effective in terms of sensitivity, although it is inferior in measurement continuity. On the other hand, in large-scale simulation experiments and actual machine tests, it is often difficult to measure the total amount of gas generated by the above method. Therefore, the NOx gas concentration is measured by a commercially available NOx gas concentration analyzer capable of continuously measuring the generated concentration, and the average NOx emission level is determined from the result, and the average NOx emission level is used as the NOx generation amount. It is also possible to use it.

  Third, an estimation formula for obtaining an estimated value of NOx amount (estimated NOx amount) is constructed from “the chemical structural species of nitrogen and the amount of NOx generated” obtained by the above experiment. The estimation formula in the present embodiment is obtained by multiplying the nitrogen amount in the solid fuel (the nitrogen amount in the fuel) by the nitrogen structure index (see (Equation 1)). The amount of nitrogen in the solid fuel is determined by the total amount of solid fuel used and the nitrogen concentration. As the nitrogen concentration, typical industrial analysis values or representative values such as scientific analysis values can be used. However, when the estimated value of the NOx amount is obtained with higher accuracy, it is desirable to use the analysis value of the solid fuel itself used in the combustion experiment. On the other hand, there is a great possibility that the method for obtaining the nitrogen structure index varies depending on the solid fuel. It is confirmed that it is possible to generally examine the nitrogen structure index in the "bonded (see (Equation 2))".

Estimated NOx amount = Nitrogen amount in fuel x Nitrogen structure index (Equation 1)
Nitrogen structure index =
[A × Type A + b × Type B + c × Type C + d × Type D + e × Type E +...] (Formula 2)
Type A, Type B, Type C,...: Ratio of each nitrogen chemical structural species a, b, c,...: Weighting parameter However, it is necessary to satisfy the following (Equation 3).
Type A + Type B + Type C + Type D + Type E +... = 1 (Expression 3)
In (Equation 1), the unit of the estimated NOx amount may be mol, mass, volume, or mass%, or may be a unit common to the right side and the left side of (Equation 1). Good.

  Subsequently, a weighting parameter is determined. Therefore, the “estimated value of the amount of NOx generated from solid fuel (estimated NOx amount)” obtained by (Equation 1) and the “the amount of NOx generated from the standard sample” obtained by the combustion experiment are compared. The weighting parameters can be determined so that these values are the best match. It is most effective to obtain an exact solution of the weighting parameter as a linear simultaneous equation. In this case, it is possible to construct an estimation formula by conducting a combustion experiment of standard samples having different ratios of nitrogen chemical structural species by the number of nitrogen chemical structural species whose weighting parameters must be determined. Is possible.

  In addition, when the data variation is large and the linearity between the nitrogen structure index and the amount of NOx generated from the solid fuel cannot be obtained, each weighting parameter can be corrected. Furthermore, when these linearities are most important, the estimated value of NOx generation amount (estimated NOx amount) generated from all standard samples and the NOx generation amount of the standard sample obtained from the result of the combustion experiment It is also effective to determine each weighting parameter by the least square method or the like so that the difference is minimized.

From the above results, the “ratio of each nitrogen chemical structure species of the target sample” obtained by the nitrogen chemical structure analysis is multiplied by a weighting parameter to obtain a nitrogen structure index, so that the amount of NOx generated from the target sample can be calculated. The estimated value (estimated NOx amount) can be calculated by (Equation 1).
The nitrogen structure index indicates the ratio of NOx in the solid fuel nitrogen in the form of the estimation formula. If the weighting parameters are determined by the above procedure, the nitrogen chemical structure of each solid fuel From the ratio of the species, it becomes possible to define and evaluate it as the generation ratio of NOx.
The construction of the above estimation formula and the calculation of the estimated NOx amount can be realized by using a computer including a CPU, a ROM, a RAM, an HDD, and the like.

Next, examples of the present invention will be described.
In this example, the following experiment was conducted to evaluate a low NOx solid fuel assuming a sinter ore production process for blast furnace raw material using combustion of coke, which is a solid fuel with low volatile content, as a heat source. It was.
First, nitrogen chemical structure analysis of coke 1, 2, 3, 4 (standard sample) used as standard in the evaluation process and coke 5 as a target sample was performed by XPS method. As a result, it was possible to classify nitrogen chemical structural species mainly into four types of structures (Type A to D).
Next, the coke 1, 2, 3, 4 used as standard was burned by a technique capable of simulating a sintering combustion field, and NOx gas was detected by FT-IR and quantified. . The nitrogen structure index is determined by a linear combination of the product of the ratio of each nitrogen chemical structural species and the weighting parameter, the weighting parameters are determined as a, b, c, and d, and the combustion experiment is performed at least four times. Was set. Table 1 shows the nitrogen concentration [% by mass] in each coke 1 to 5, the structure type (Type A to D) of each nitrogen chemical structural species, and the structure ratio [%].

  Secondly, a structure index according to the following (formula 4) in which weighting parameters (a to d) are added to the ratio of the structure type of each nitrogen chemical structural species (Type A to Type D) was assumed.

Structure index =
[A × Type A + b × Type B + c × Type C + d × Type D] (Formula 4)

  Further, in order to determine the structure index, for coke 1 to 4 which are standard samples, the value obtained by multiplying the structure index by the nitrogen concentration and the total amount of NOx gas generated in the combustion experiment are equally set, and a simultaneous equation is established. Thus, the weighting parameters a, b, c, and d were obtained. As a result, a = 0.18, b = 0.08, c = 0.52, and d = 0.22. When this result was applied to the result of coke 5, the structure index was 0.089. When this structure index is multiplied by the nitrogen concentration of the coke 5, the amount of NOx predicted to be generated from the coke 5 (estimated NOx amount) is about 0.098. Therefore, it was possible to evaluate that the coke 5 has a smaller amount of NOx generation than other coal types whose estimated NOx amount exceeds 0.12. Thus, it becomes possible to predict the amount of NOx generated per unit of fuel (nitrogen amount) to be used.

In addition, as a result of conducting a combustion experiment for coke 5 for confirmation, the amount of NOx generated was about 0.111. Similar to the result of the estimated NOx amount calculated from the structure index, the coke 4 showed that the NOx generation amount was smaller than the other cokes whose NOx generation amount exceeded 0.113. FIG. 2 shows the relationship between the NOx generation amount (NOx generation amount) obtained from the combustion experiment and the estimated value of NOx generation amount calculated from the structure index (structure index × nitrogen concentration) for each of the cokes 1 to 5. FIG. In FIG. 2, plots indicated by “1”, “2”, “3”, “4”, and “5” indicate values for cokes 1, 2, 3, 4, and 5, respectively. As shown in FIG. 2, for each of the cokes 1 to 5, the NOx generation amount obtained from the combustion experiment is relatively small (large), and the estimated value of the NOx generation amount calculated from the structure index is also relative. It can be seen that there is a tendency to be small (large).
As described above, the structural index is determined by analyzing the nitrogen chemical structure of typical carbon materials and the minimum number of combustion experiments. For new carbon materials, the rate of NOx generation after combustion can be determined only by structural analysis. It was shown that it can be estimated.

Of the embodiments of the present invention described above, at least the construction of the estimation formula and the calculation of the estimated value can be realized by a computer executing a program. Further, a computer-readable recording medium in which the program is recorded and a computer program product such as the program can also be applied as an embodiment of the present invention. As the recording medium, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.
In addition, the embodiments of the present invention described above are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

  101-105 XPS spectrum

Claims (6)

A solid fuel evaluation method for estimating the amount of nitrogen oxides generated from solid fuel during the production of sintered ore for blast furnace raw material,
A structure ratio deriving step of performing a nitrogen chemical structure analysis of a plurality of types of standard fuel and the solid fuel to obtain a structure ratio of various nitrogen chemical structure species in each of the plurality of types of standard fuel and the solid fuel,
A nitrogen oxide generation amount derivation step of performing a combustion experiment on the plurality of types of standard fuel to obtain a generation amount of nitrogen oxide generated from the plurality of types of standard fuel;
Using the amount of nitrogen oxide generated in the plurality of types of standard fuel and the structure ratio of nitrogen chemical structural species in the plurality of types of standard fuel, the amount of nitrogen oxide generated in the solid fuel having an arbitrary structural ratio is determined. An estimation formula deriving step for obtaining an estimation formula to be estimated;
A nitrogen oxide generation amount estimating step of estimating a generation amount of nitrogen oxide generated from the solid fuel using the estimation formula from a structural ratio of nitrogen chemical structural species in the solid fuel;
A solid fuel evaluation method comprising: The nitrogen oxide generation amount derivation step includes
The standard fuel combustion experiment was performed as many times as the number of nitrogen chemical structural species in the solid fuel, in which the structural ratio was determined in the structural ratio derivation step,
The estimation formula deriving step includes:
The estimation formula is obtained by using the generation amount of nitrogen oxide of the standard fuel obtained in each of the standard fuel combustion experiments and the structure ratio of the nitrogen chemical structural species in the plurality of types of standard fuels. The solid fuel evaluation method according to claim 1. The estimation formula is
It is an equation for deriving a value obtained by multiplying the amount of nitrogen in the solid fuel by the nitrogen structure index as an estimated value of the amount of nitrogen oxide generated in the solid fuel,
The nitrogen structure index is
The nitrogen structure index corresponding to the ratio of nitrogen contained in the solid fuel to nitrogen oxides when burning the solid fuel, the structure ratio of the nitrogen chemical structural species, and the weighting parameter of the structure ratio of the nitrogen chemical structural species, The solid fuel evaluation method according to claim 1, wherein the index is a nitrogen structure index represented by a linear combination formula of the products of: The estimation formula deriving step includes:
Measuring the nitrogen concentration of the standard fuel and the nitrogen concentration of the solid fuel;
A simultaneous equation is established by setting that the value obtained by multiplying the nitrogen structure index by the amount of nitrogen in the solid fuel obtained from the nitrogen concentration is equal to the amount of nitrogen oxide generated in the combustion experiment of the standard fuel. The solid fuel evaluation method according to claim 3, further comprising: determining the weighted parameter from simultaneous equations. The structural ratio derivation step includes
Of the XPS spectra of the nitrogen 1s orbit obtained by conducting a nitrogen chemical structure analysis by XPS (X-ray Photoelectron Spectroscopy) method on the plurality of types of standard fuel and the solid fuel, 398.6 eV to 399.0 eV, 400 Regions having five peaks centered at 0.0 eV to 400.4 eV, 401.2 eV to 401.6 eV, 402.3 eV to 402.7 eV, and 403.6 eV to 404.0 eV, and the various nitrogen chemical structures. 2. The structure ratio of the various nitrogen chemical structural species is determined from the ratio of the area of the region having each peak to the total area of the regions having all the peaks, belonging to the species. The solid fuel evaluation method of any one of -4.   The solid fuel evaluation method according to any one of claims 1 to 5, wherein the solid fuel is a coal distillate or anthracite having a volatile content of 10% by mass or less.

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