Prediction method for carbon content in coal

Abstract

The invention provides a method for predicting the carbon content in coal. The prediction method comprises the following steps: detecting to obtain a plurality of groups of experimental data of general analysis test coal samples, wherein each group of experimental data comprises dry basis volatile components, dry basis ash content, dry basis constant volume high calorific value and dry basis carbon content; taking the dry basis volatile component, the dry basis ash content and the dry basis constant-volume high calorific value of each group of experimental data as independent variables and the dry basis carbon content as a dependent variable, establishing a nonlinear mapping relationship among the dry basis volatile component, the dry basis ash content, the dry basis constant-volume high calorific value and the dry basis carbon content by adopting a response surface method, and fitting to obtain a prediction model. According to the method, the carbon content of the coal can be quickly predicted, the carbon content of the coal can be obtained through conventional analysis and calculation under the condition that the determination condition of the carbon content of the coal is not provided, and the quality, combustion characteristics and environmental influence of the coal can be evaluated.

Description

Technical Field

[0001] This application belongs to the field of coal quality testing technology, specifically, it relates to a method for predicting the carbon content in coal. Background Technology

[0002] Carbon in coal is the primary source of heat generated during combustion. It is the most important constituent element and structural framework of coal, and is crucial for assessing coal quality, combustion characteristics, and environmental impact. The carbon content in coal is a primary basis for calculating carbon emissions by power generation companies, making the accuracy of its detection paramount. However, traditional methods for detecting carbon content in coal rely on laboratory chemical analysis, such as the three-stage furnace method, the two-stage furnace method, the coulometric method, infrared spectroscopy, X-ray fluorescence spectroscopy, and atomic absorption spectrometry. These methods require high-temperature combustion, are time-consuming, costly, and the instruments often have poor stability and require frequent maintenance. Many power generation companies lack the necessary experimental facilities for detecting carbon content in coal. Summary of the Invention

[0003] The technical problem addressed by this application is: how to conveniently and quickly predict the carbon content in coal.

[0004] This application provides a method for predicting the carbon content in coal, the method comprising:

[0005] Several sets of experimental data for general analysis coal samples were obtained. Each set of experimental data includes volatile matter on a dry basis, ash on a dry basis, higher calorific value on a dry basis at constant volume, and carbon content on a dry basis.

[0006] Using the volatile matter, ash content, and higher heating value of the dry basis at constant volume for each experimental data set as independent variables and the carbon content of the dry basis as the dependent variable, a nonlinear mapping relationship between the volatile matter, ash content, higher heating value at constant volume, and carbon content of the dry basis was established using response surface methodology. The resulting prediction model was then fitted.

[0007]

[0008] In the formula, V d A is a dry basis volatile component. d Ash content on a dry basis, Q gr,v,d For the dry-balanced constant-volume higher calorific value, C d This represents the carbon content on a dry basis.

[0009] Optionally, the method for detecting the ash content on a desiccated basis includes:

[0010] The air-dried moisture content M was determined by heating a general analytical test coal sample using an industrial analyzer. ad Air-dried basis ash A ad ;

[0011] According to the air-dried basis moisture Mad Ash content A on air-dried basis ad The ash content A on a dry basis was calculated. d .

[0012] Optionally, the method for determining the volatile matter on a dry basis includes:

[0013] A typical analytical test coal sample was placed in a preheated muffle furnace, and the volatile matter V on an air-dried basis was measured. ad According to the air-dried basis volatile matter V ad The volatile matter V on the dry basis was calculated. d .

[0014] Optionally, the method for detecting the higher heating value of a dry basis at constant volume includes:

[0015] The calorific value of the coal sample in a general analytical test was measured using an adiabatic oxygen bomb calorimeter, and the higher heating value Q on an air-dried basis at constant volume was calculated. gr,v,ad Then, the higher heating value Q of the dry basis at constant volume is calculated. gr,v,d .

[0016] Optionally, the method for detecting the carbon content on the dried basis includes:

[0017] The air-dried carbon content (C) of coal was measured using a carbon, hydrogen, and nitrogen elemental analyzer. ad Then, the carbon content C of the dry basis was calculated. d .

[0018] The method for predicting the carbon content in coal provided in this application has the following technical advantages:

[0019] This method calculates the carbon content in coal by substituting conventional experimental values ​​such as dry-basis ash content, dry-basis volatile matter, and dry-basis constant-volume higher calorific value of coal samples into a prediction model. It can be applied to predict the carbon content in coal used in thermal power plants. The operation is simple and rapid, and the prediction model has a high accuracy rate. Attached Figure Description

[0020] Figure 1 This is a flowchart of a method for predicting the carbon content in coal according to one or more embodiments.

[0021] Figure 2 This is a schematic diagram showing the measured and predicted values ​​of carbon content in coal according to one or more embodiments. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0023] Before describing the various embodiments of this application in detail, the technical concept of this application is first briefly described: Currently, the carbon content in coal is usually determined in a laboratory using specialized instruments and equipment, which is inconvenient. Therefore, this application provides a method for predicting the carbon content in coal. This involves measuring experimental data from several sets of coal samples, using the dry-basis volatile matter, dry-basis ash content, and dry-basis constant-volume higher heating value of each set of experimental data as independent variables and the dry-basis carbon content as the dependent variable. A nonlinear mapping relationship is established, and a prediction model is fitted to obtain the model. This prediction model can be used to predict the carbon content in coal. The dry-basis volatile matter, dry-basis ash content, and dry-basis constant-volume higher heating value are easily detectable parameters and are generally required for routine analysis. Therefore, this method is beneficial for quickly predicting the carbon content in coal. Even without the ability to measure the carbon content in coal, the carbon content can still be obtained through routine analysis and calculation. The specific principles of the method for predicting the carbon content in coal of this application are described below with reference to more embodiments.

[0024] Specifically, such as Figure 1 As shown, the method for predicting the carbon content in coal in this embodiment includes the following steps:

[0025] Step S10: Measure and obtain experimental data for several sets of general analytical test coal samples. Each set of experimental data includes volatile matter on a dry basis, ash on a dry basis, higher heating value on a dry basis at constant volume, and carbon content on a dry basis.

[0026] Step S20: Using the volatile matter, ash content, and higher heating value at constant volume of the dry basis as independent variables and the carbon content of the dry basis as the dependent variable for each set of experimental data, a nonlinear mapping relationship between the volatile matter, ash content, higher heating value at constant volume of the dry basis, and carbon content of the dry basis is established using response surface methodology, and a prediction model is obtained by fitting the model.

[0027]

[0028] In the formula, V d A is a dry basis volatile component. d Ash content on a dry basis, Q gr,v,d For the dry-balanced constant-volume higher calorific value, C d This represents the carbon content on a dry basis.

[0029] Before testing various experimental data, it is necessary to prepare general analytical test coal samples. Specifically, according to GB / T19494.2-2023 "Mechanized Sampling of Coal - Part 2: Preparation of Coal Samples", 80 kinds of coal from different power plants and different varieties are selected, and after sampling, crushing, reducing, mixing and drying, general analytical test coal samples are prepared as samples for test analysis.

[0030] For example, according to GB / T 30732-2014 "Industrial Analysis Methods for Coal - Instrumental Method", a sample of (1±0.1) g is weighed and placed in an industrial analyzer. It is dried in a heating furnace at 105℃~110℃ until constant mass is achieved. The moisture content of the coal sample is calculated based on the mass loss of the coal sample. Another sample of (1±0.1) g is weighed and heated in a heating furnace to (815±10)℃ according to a prescribed procedure. During this process, it is ashed in an air stream and ignited until constant mass is achieved. The ash content of the coal sample is calculated based on the mass of the residue. The air-dried basis moisture content M of the sample is then obtained. ad Air-dried basis ash A ad Ash content on dry basis A d .

[0031] Air-dried basis moisture content of coal samples:

[0032] In the formula, M ad denoted as , where is the mass fraction of moisture in the general analytical test coal sample; m is the mass of the general analytical test coal sample weighed; and m1 is the mass lost by the coal sample after drying.

[0033] Air-dried ash content of coal samples:

[0034] In the formula, A ad denoted as , where m is the mass fraction of the air-dried ash content of the coal sample; m is the mass of the general analytical test coal sample weighed; and m1 is the mass of the residue after ignition.

[0035] Ash content of coal samples on a dry basis:

[0036] In the formula, A d A represents the mass fraction of ash content on a dry basis in the coal sample. ad M represents the mass fraction of ash on an air-dried basis in the coal sample. ad This represents the mass fraction of moisture on an air-dried basis in the coal sample.

[0037] For example, according to GB / T 212-2008 "Industrial Analysis Methods for Coal", (1±0.01) g of sample was weighed and placed in a covered porcelain crucible, and heated in a muffle furnace at (900±10)℃ for 7 min in the absence of air. The volatile matter of the coal sample was calculated by subtracting the moisture content of the coal sample from the mass fraction of the reduced mass. The air-dried volatile matter V of the sample was then measured. ad The volatile matter V on the dry basis was calculated. d .

[0038] Air-dried volatile matter of coal sample:

[0039] In the formula, V addenoted as ν, where m is the mass fraction of volatile matter on an air-dried basis of the coal sample; m is the mass of the general analytical test coal sample weighed; m1 is the mass reduction of the coal sample after heating; M ad This represents the mass fraction of moisture on an air-dried basis in the coal sample.

[0040] Volatile matter on a dry basis of the coal sample:

[0041] In the formula, V d V represents the mass fraction of volatile matter on a dry basis in the coal sample. ad M represents the mass fraction of volatile matter on an air-dried basis in the coal sample. ad This represents the mass fraction of moisture on an air-dried basis in the coal sample.

[0042] For example, according to GB / T 213-2008 "Determination of Calorific Value of Coal", a sample of (1±0.1) g was weighed, and the calorific value of the sample was measured using an adiabatic automatic oxygen bomb calorimeter. The air-dried constant-volume higher calorific value Q was then calculated. gr,v,ad And the high calorific value Q of dry basis at constant volume gr,v,d .

[0043] Air-dried basis constant-volume higher calorific value of coal sample: Q gr,v,ad =Q b,ad -(94.1S b,ad +αQ b,ad )

[0044] In the formula, Q gr,v,ad Q is the air-dried, constant-volume higher calorific value of coal. b,ad The calorific value of the bomb sample for air-dried coal; S b,ad The sulfur content is measured from the washing solution of the bomb; 94.1 is the correction value per 1.00% sulfur in the air-dried coal sample; α is the correction factor for the heat of nitric acid formation: when Q b When ≤16.70 MJ / kg, α=0.0010; when 16.70<Q b When Q is ≤25.10 MJ / kg, α=0.0012. b When the concentration is >25.10 MJ / kg, α = 0.0016.

[0045] For example, according to GB / T 30733-2014 "Determination of Carbon, Hydrogen and Nitrogen in Coal - Instrumental Method", a sample of not less than 70 mg is weighed and fully combusted in a high temperature and oxygen stream using a carbon, hydrogen and nitrogen elemental analyzer. The carbon in the coal is converted into carbon dioxide, which is then quantitatively determined by a specific detection system. The measured air-dried basis carbon content (C) of the sample is then determined. ad The carbon content C on the dry basis was calculated. d .

[0046] Dry basis carbon content of coal samples:

[0047] Using the response surface methodology, with (100-A) d V d Q gr,v,d As the independent variable, C d As the response variable, establish (100-A) d V d Q gr,v,d With C d The nonlinear mapping relationship between them enables the mapping of C. d The prediction. Since the ash content of coal is generally inversely proportional to the carbon content, the higher the ash content, the lower the carbon content, therefore, (100-A) is used as the basis for prediction. d Using as the independent variable, the resulting prediction model is as follows:

[0048]

[0049] In the formula, V d A is a dry basis volatile component. d Ash content on a dry basis, Q gr,v,d For the dry-balanced constant-volume higher calorific value, C d This represents the carbon content on a dry basis.

[0050] For example, the (100-A) of different coal types from different power plants was measured experimentally. d ), Q gr,v,d V d C d and C d The predicted values ​​of the fitted equation are shown in Table 1. The predicted value C of the prediction model... d 'Compared with experimentally measured value C d The relationship between them is as follows Figure 2 As shown. By Figure 2 As shown in Table 1, C d The measured values ​​are very close to the predicted values, indicating that the established model has high accuracy. The coefficient of determination R of this model is... 2 =0.998, indicating a good fitting effect and the ability to predict the carbon content in coal well.

[0051] Table 1

[0052]

[0053]

[0054]

[0055] This method calculates the carbon content in coal by substituting the measured values ​​of dry-based coal ash content, dry-based volatile matter, and dry-based constant-volume higher calorific value into a prediction model. It can be applied to predict the carbon content in coal used in thermal power plants. The operation is simple and quick, and the prediction model has a high accuracy rate.

[0056] The specific embodiments of this application have been described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that modifications and improvements can be made to these embodiments without departing from the principles and spirit of this application as defined by the claims and their equivalents, and such modifications and improvements should also be within the protection scope of this application.

Claims

1. A method for predicting the carbon content in coal, characterized in that, The prediction method includes: Several sets of experimental data for general analysis coal samples were obtained. Each set of experimental data includes volatile matter on a dry basis, ash on a dry basis, higher calorific value on a dry basis at constant volume, and carbon content on a dry basis. Using the volatile matter, ash content, and higher heating value of the dry basis at constant volume for each experimental data set as independent variables and the carbon content of the dry basis as the dependent variable, a nonlinear mapping relationship between the volatile matter, ash content, higher heating value at constant volume, and carbon content of the dry basis was established using response surface methodology. The resulting prediction model was then fitted. In the formula, V d A is a dry basis volatile component. d Ash content on a dry basis, Q gr,v,d For the dry-balanced constant-volume higher calorific value, C d This represents the carbon content on a dry basis.

2. The method for predicting the carbon content in coal according to claim 1, characterized in that, Methods for determining the ash content on a dried basis include: The air-dried moisture content M was determined by heating a general analytical test coal sample using an industrial analyzer. ad Air-dried basis ash A ad ; According to the air-dried basis moisture M ad Ash content A on air-dried basis ad The ash content A on a dry basis was calculated. d .

3. The method for predicting carbon content in coal according to claim 1, characterized in that, Methods for determining volatile matter on a dry basis include: A typical analytical test coal sample was placed in a preheated muffle furnace, and the volatile matter V on an air-dried basis was measured. ad ; According to the air-dried base volatile matter V ad The volatile matter V on the dry basis was calculated. d .

4. The method for predicting the carbon content in coal according to claim 1, characterized in that, Methods for detecting the high calorific value of a dry basis at constant volume include: The calorific value of the coal sample in a general analytical test was measured using an adiabatic oxygen bomb calorimeter, and the higher heating value Q on an air-dried basis at constant volume was calculated. gr,v,ad Then, the higher heating value Q of the dry basis at constant volume is calculated. gr,v,d .

5. The method for predicting the carbon content in coal according to claim 1, characterized in that, Methods for detecting carbon content on a dried basis include: The air-dried carbon content (C) of coal was measured using a carbon, hydrogen, and nitrogen elemental analyzer. ad The carbon content C on the dry basis was calculated. d .

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