A method of testing viscosity-temperature characteristics

Abstract

The present application provides a kind of method for testing viscosity-temperature characteristics, belongs to coal ash characteristics detection field.The method utilizes ash melting point tester to determine the viscosity-temperature characteristics of coal sample ash, and the viscosity characteristics of ash cone when reaching original shape temperature, deformation temperature, softening temperature, half ball temperature and flow temperature are respectively recorded as a, b, c, d and e, and the corresponding temperatures are sequentially recorded as T1, T2, T3, T4 and T5;Between original shape temperature and deformation temperature, between deformation temperature and softening temperature, between softening temperature and half ball temperature, between half ball temperature and flow temperature, a characteristic state is taken respectively, and the viscosity characteristics are sequentially recorded as f, g, h and i;According to the test data, the viscosity-temperature characteristics test curve of temperature and viscosity relationship is drawn.The present application simplifies the existing coal ash viscosity-temperature characteristics test process, improves work efficiency and reduces measurement error.

Description

Technical Field

[0001] This invention belongs to the field of coal ash characteristic detection technology, and specifically relates to a method for testing viscosity-temperature characteristics. Background Technology

[0002] The viscosity-temperature characteristics of coal ash refer to the relationship between the viscosity of coal ash forming molten ash at high temperatures and temperature. Coal ash viscosity is an important indicator for power generation and gasification coal, and also a crucial parameter in boiler design; accurate measurement of coal ash viscosity has significant practical implications. The viscosity-temperature characteristics and fusibility of coal ash are related not only to its chemical composition but also to the types of minerals present at high temperatures. Coal ash fusibility characterizes the physical state of coal ash under certain conditions, exhibiting deformation, softening, hemispherical formation, and flow characteristics as the heating temperature increases. When a coal ash sample is heated under specified conditions, as the temperature rises, the sample will partially melt to completely melt, accompanied by certain physical states: deformation, softening, hemispherical formation, and flow. The temperatures at which these four points of change in coal ash fusibility occur are primarily determined by the mineral composition of the coal ash. The mineral composition of coal is extremely complex, mainly consisting of a complex mixture of oxides and compounds of various elements such as silicon, aluminum, titanium, calcium, and magnesium. In current national standards, the physical state of coal ash is typically represented by four temperatures: deformation temperature (DT), softening temperature (ST), hemispherical temperature (HT), and flow temperature (FT). GB / T / 219—2008 specifies the method for determining the melting point of coal ash: the coal ash obtained by calcining the analytical sample at a certain temperature is used to form a triangular ash cone of a specific size in a specified ash cone mold. The ash cone is then heated in a specific gaseous medium, and the morphological changes of the ash cone during heating are observed. The characteristic melting temperatures, namely deformation temperature (DT), softening temperature (ST), hemispherical temperature (HT), and flow temperature (FT), are observed and recorded. Currently, domestic and international experts and scholars have established empirical formulas for predicting ash viscosity by seeking the relationship between ash composition and ash viscosity. However, these empirical formulas are complex and difficult to understand, inconvenient for calculation, and have low calculation accuracy. For example, patent application number 2017102464057 provides a method for predicting the viscosity-temperature characteristics of coal ash. This method detects the coal ash composition and uses a high-temperature ash viscometer to measure the ash viscosity of coal samples at temperatures between 1100°C and 1500°C, establishing a relationship between coal ash composition and ash viscosity to form an ash viscosity prediction model. However, this method involves using a high-temperature ash viscometer to measure the ash viscosity of the coal sample, which is a complex and time-consuming process. The prediction model is also relatively complex and difficult to calculate. Furthermore, some literature has reported models for predicting the viscosity-temperature characteristics of coal ash, such as the Watt-Fereday model, the Ribod model, and the Kalmanovitch-Frank model. These models are all complex and have low accuracy. Summary of the Invention

[0003] The purpose of this invention is to provide a method for testing viscosity-temperature characteristics, which simplifies the existing coal ash viscosity testing process, improves work efficiency, and reduces measurement errors.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for testing viscosity-temperature characteristics includes the following steps: (1) Take a coal sample and use an ash melting point tester to determine the viscosity-temperature characteristics of the coal sample ash. Record the viscosity characteristics of the ash cone when it reaches the original temperature, deformation temperature, softening temperature, hemispherical temperature and flow temperature as a, b, c, d and e respectively, and record the corresponding temperatures as T1, T2, T3, T4 and T5 respectively. (2) Then, take a characteristic state between the original temperature and the deformation temperature, and denote its viscosity characteristics as f and the corresponding temperature as T6. Take a characteristic state between the deformation temperature and the softening temperature, and denote its viscosity characteristics as g and the corresponding temperature as T7. Take a characteristic state between the softening temperature and the hemispherical temperature, and denote its viscosity characteristics as h and the corresponding temperature as T8. Take a characteristic state between the hemispherical temperature and the flow temperature, and denote its viscosity characteristics as i and the corresponding temperature as T9. (3) Plot the viscosity-temperature characteristic test curve of the relationship between temperature and viscosity based on the test data.

[0005] Furthermore, the viscosity characteristics are measured using a molten ash cone height gauge, in mm.

[0006] Furthermore, the test data were subjected to curve fitting using Excel, Matlab, and Origin software to obtain viscosity-temperature characteristic fitting curves. The independent variable for curve fitting was temperature T, and the dependent variable was viscosity characteristic η.

[0007] Furthermore, the fitting formula for the viscosity-temperature characteristic curve is: η = AlnT + B; where η is the viscosity characteristic in mm and T is the temperature in °C.

[0008] Furthermore, the viscosity-temperature characteristic fitting curve is corrected using the characteristic parameters in the correction fitting formula to obtain the target viscosity-temperature characteristic curve.

[0009] Furthermore, the correction fitting equation for the viscosity-temperature characteristic curve is: η = αA ， ln(T+γ)+βB ， ; where α, β, and γ are correction coefficients, and the values ​​of correction coefficients α, β, and γ are determined by the silicon-aluminum ratio, iron-calcium-magnesium ratio, and acid-base ratio of the coal sample, respectively.

[0010] Furthermore, the silicon-aluminum ratio, iron-calcium-magnesium ratio, and acid-base ratio of the coal sample were determined by X-ray fluorescence spectrometry based on the content of SiO2, Al2O3, Fe2O3, MgO, and CaO in the coal sample. Then, the silicon-aluminum ratio α, iron-calcium-magnesium ratio β, and acid-base ratio γ in the coal sample were calculated respectively, where α = w(SiO2) / w(Al2O3), β = w(Fe2O3) / w(MgO+CaO), and γ = w(SiO2+Al2O3) / w(Fe2O3+MgO+CaO).

[0011] Compared with the prior art, the beneficial technical effects of the present invention are as follows: The method for testing viscosity-temperature characteristics of the present invention is used for rapid testing of the viscosity-temperature characteristics of coal ash, which simplifies the existing coal ash viscosity testing process and improves work efficiency; by using Excel, Matlab, and Origin software to perform curve fitting on the test data to obtain the viscosity-temperature characteristic fitting curve, the test data can be corrected and the measurement error reduced; by using the characteristic parameters in the correction fitting formula to correct the viscosity-temperature characteristic fitting curve to obtain the target viscosity-temperature characteristic curve, it can be used as a high-precision viscosity-temperature index prediction model to predict the viscosity-temperature characteristics of coal ash. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of viscosity characteristics using a gray cone height gauge in one embodiment of the present invention; Figure 2 This is a graph showing the viscosity-temperature characteristic test curve and the viscosity-temperature characteristic fitting curve in one embodiment of the present invention. Detailed Implementation

[0013] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Those skilled in the art should understand that the following examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims.

[0014] A method for testing viscosity-temperature characteristics includes the following steps: (1) Take a coal sample and use an ash melting point tester to determine the viscosity-temperature characteristics of the coal sample ash. Record the viscosity characteristics of the ash cone when it reaches the original temperature, deformation temperature, softening temperature, hemispherical temperature and flow temperature as a, b, c, d and e respectively, and record the corresponding temperatures as T1, T2, T3, T4 and T5 respectively. (2) Then, take a characteristic state between the original temperature and the deformation temperature, and denote its viscosity characteristics as f and the corresponding temperature as T6. Take a characteristic state between the deformation temperature and the softening temperature, and denote its viscosity characteristics as g and the corresponding temperature as T7. Take a characteristic state between the softening temperature and the hemispherical temperature, and denote its viscosity characteristics as h and the corresponding temperature as T8. Take a characteristic state between the hemispherical temperature and the flow temperature, and denote its viscosity characteristics as i and the corresponding temperature as T9. (3) Plot the viscosity-temperature characteristic test curve of the relationship between temperature and viscosity based on the test data.

[0015] Specifically, the viscosity characteristics are measured using a molten ash cone height gauge, in mm.

[0016] Specifically, the test data were used to perform curve fitting using Excel, Matlab, and Origin software to obtain viscosity-temperature characteristic fitting curves. The independent variable for curve fitting was temperature T, and the dependent variable was viscosity characteristic η.

[0017] Specifically, the fitting formula for the viscosity-temperature characteristic curve is: η = AlnT + B; where η is the viscosity characteristic in mm and T is the temperature in °C.

[0018] Specifically, the viscosity-temperature characteristic fitting curve is corrected using the characteristic parameters in the correction fitting formula to obtain the target viscosity-temperature characteristic curve.

[0019] Specifically, the calibration fitting equation for the calibration viscosity-temperature characteristic curve is: η = αA ， ln(T+γ)+βB ， ; where α, β, and γ are correction coefficients, and the values ​​of correction coefficients α, β, and γ are determined by the silicon-aluminum ratio, iron-calcium-magnesium ratio, and acid-base ratio of the coal sample, respectively.

[0020] Specifically, the silicon-aluminum ratio, iron-calcium-magnesium ratio, and acid-base ratio of the coal sample were determined by X-ray fluorescence spectrometry using the content of SiO2, Al2O3, Fe2O3, MgO, and CaO in the ash of the coal sample. Then, the silicon-aluminum ratio α, iron-calcium-magnesium ratio β, and acid-base ratio γ in the coal sample were calculated respectively, where α = w(SiO2) / w(Al2O3), β = w(Fe2O3) / w(MgO+CaO), and γ = w(SiO2+Al2O3) / w(Fe2O3+MgO+CaO). Example 1

[0021] Taking raw coal from a certain region in Xinjiang as the research object, ash cone samples were prepared according to the provisions of GB / T / 219—2008. The carbon sealing method was used, and the ash fusion temperature of the coal sample was measured using an ash fusion point analyzer under a weakly reducing atmosphere. This included the original temperature T1, deformation temperature T2, softening temperature T3, hemispherical temperature T4, and flow temperature T5. Characteristic states were selected between the original temperature T1 and deformation temperature T2, between deformation temperature T2 and softening temperature T3, between softening temperature T3 and hemispherical temperature T4, and between hemispherical temperature T4 and flow temperature T5, and were successively denoted as T6, T7, T8, and T9. At the corresponding temperatures, the height of the molten ash cone was measured as a viscosity characteristic. Figure 1 The numbers are denoted as a, b, c, d, e, f, g, h, and i, respectively. The test results are shown in Table 1.

[0022] Table 1. Melting temperature and viscosity characteristics of coal ash

[0023] Based on the data in the table above, plot the viscosity-temperature characteristic test curve with temperature T on the x-axis and viscosity characteristic η on the y-axis, as shown. Figure 2 As shown. Example 2

[0024] Based on Example 1, the viscosity-temperature characteristic fitting curve was obtained by using Excel to perform curve fitting on the test data in Table 1. The independent variable of the curve fitting was temperature T, and the dependent variable was viscosity characteristic η. The viscosity-temperature characteristic fitting curve is shown below. Figure 2 As shown, the fitting formula for the viscosity-temperature characteristic curve is: η = -42.04lnT + 303.02, where η is the viscosity characteristic in mm and T is the temperature in °C. Example 3

[0025] Based on Example 2, the viscosity-temperature characteristic fitting curve is corrected using the characteristic parameters in the correction fitting formula to obtain the target viscosity-temperature characteristic curve; the correction fitting formula for the corrected viscosity-temperature characteristic curve is: η=αA ， ln(T+γ)+βB ， ; where α, β, and γ are correction coefficients, and the values ​​of correction coefficients α, β, and γ are determined by the silicon-aluminum ratio, iron-calcium-magnesium ratio, and acid-base ratio of the coal sample, respectively.

[0026] In this embodiment, the silicon-aluminum ratio, iron-calcium-magnesium ratio, and acid-base ratio of the coal sample were determined by X-ray fluorescence spectrometry using the content of SiO2, Al2O3, Fe2O3, MgO, and CaO in the ash of the coal sample. Then, the silicon-aluminum ratio α, iron-calcium-magnesium ratio β, and acid-base ratio γ in the coal sample were calculated respectively, where α = w(SiO2) / w(Al2O3), β = w(Fe2O3) / w(MgO+CaO), and acid-base ratio γ.

[0027] Those skilled in the art should understand that any modifications, equivalent substitutions, or improvements made to the above embodiments based on the technical essence of this invention should be included within the scope of protection of this invention.

Claims

1. A method for testing viscosity-temperature characteristics, characterized in that, Includes the following steps: (1) Take a coal sample and use an ash melting point tester to determine the viscosity-temperature characteristics of the coal sample ash. Record the viscosity characteristics of the ash cone when it reaches the original temperature, deformation temperature, softening temperature, hemispherical temperature and flow temperature as a, b, c, d and e respectively, and record the corresponding temperatures as T1, T2, T3, T4 and T5 respectively. (2) Then, take a characteristic state between the original temperature and the deformation temperature, and denote its viscosity characteristics as f and the corresponding temperature as T6. Take a characteristic state between the deformation temperature and the softening temperature, and denote its viscosity characteristics as g and the corresponding temperature as T7. Take a characteristic state between the softening temperature and the hemispherical temperature, and denote its viscosity characteristics as h and the corresponding temperature as T8. Take a characteristic state between the hemispherical temperature and the flow temperature, and denote its viscosity characteristics as i and the corresponding temperature as T9. (3) Plot the viscosity-temperature characteristic test curve based on the test data to show the relationship between temperature and viscosity; The test data were used to perform curve fitting using Excel, Matlab, and Origin software to obtain viscosity-temperature characteristic fitting curves. The independent variable for curve fitting was temperature T, and the dependent variable was viscosity characteristic η. The fitting formula for the viscosity-temperature characteristic curve is: η = AlnT + B; where η is the viscosity characteristic in mm and T is the temperature in °C. The viscosity-temperature characteristic fitting curve is corrected using the characteristic parameters in the correction fitting formula to obtain the target viscosity-temperature characteristic curve; The calibration fitting formula for the viscosity-temperature characteristic curve is: η=αAln(T+γ)+βB; where α, β, and γ are calibration coefficients, and the values ​​of calibration coefficients α, β, and γ are determined by the silica-alumina ratio, iron-calcium-magnesium ratio, and acid-base ratio of the coal sample, respectively. The viscosity characteristics were measured using a melted ash cone height gauge, in mm.

2. The method according to claim 1, characterized in that: The silicon-aluminum ratio, iron-calcium-magnesium ratio, and acid-base ratio of the coal sample were determined by X-ray fluorescence spectrometry using the content of SiO2, Al2O3, Fe2O3, MgO, and CaO in the ash of the coal sample. Then, the silicon-aluminum ratio α, iron-calcium-magnesium ratio β, and acid-base ratio γ in the coal sample were calculated respectively, where α = w(SiO2) / w(Al2O3), β = w(Fe2O3) / w(MgO+CaO), and γ = w(SiO2+Al2O3) / w(Fe2O3+MgO+CaO).

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