A method and system for predicting the ignition temperature of mixed coal based on single coal thermal weight loss data

Abstract

The application discloses a method and system for predicting a mixed coal ignition temperature based on single coal thermal weightlessness data, and the method comprises the following steps: weighting and averaging the thermal weightlessness data of each single coal to obtain a thermal weightlessness data curve TG mix of the mixed coal mix , deriving the curve DTG mix , obtaining the thermal weightlessness data curve TG mix of the mixed coal and the curve DTG mix , and obtaining the ignition temperature IT mix of the mixed coal by using a plotting method. The application can realize the prediction of the ignition temperature of mixed coal with any blending ratio based on the single coal thermal weightlessness data, has the advantages of convenient and fast prediction and high prediction accuracy, can provide a reference for coal blending and blending combustion of a coal-fired boiler, operation optimization, boiler furnace design, combustor design and safety check of a pulverizing system, and is convenient for intelligent management of the coal blending and blending combustion of a power plant.

Description

Technical Field

[0001] This invention belongs to the field of thermal power engineering, specifically relating to a method and system for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data. Background Technology

[0002] In pulverized coal power plant boilers, pulverized coal is fed into the furnace in an airflow manner and continuously ignites under the heating of high-temperature flue gas, ensuring stable combustion within the furnace. The continuous ignition of the pulverized coal airflow depends on the flue gas temperature level within the furnace and the combustion characteristics of the coal. Ignition temperature is one of the important parameters of coal combustion characteristics; different types of coal have different ignition temperatures. Under the same conditions, the lower the ignition temperature, the more stable the combustion. Therefore, understanding the ignition temperature of the coal is of great guiding significance for the operation of power plant boilers. For a given pulverized coal boiler, it has a certain adaptability to the quality of the coal fed into the furnace, usually within a certain fluctuation range of the design coal quality. Due to changes in the coal market, it is common for the actual coal quality fed into the boiler to deviate from the design coal quality. There are many different types of coal, and the differences in coal quality between them can vary greatly. To make the coal quality fed into the furnace as close as possible to the design coal quality, blending is usually adopted. By controlling the blending ratio of different coal types, the various indicators of the mixed fuel are made close to the design coal quality, ensuring the stability and economy of combustion in the furnace.

[0003] When blending multiple coal types, the ignition temperature of the mixed fuel is a crucial control factor. Since testing the ignition temperature of pulverized coal requires specialized equipment, and ignition temperature corresponds to the volatile matter content of each coal type, volatile matter content is typically used as the primary control indicator for blending in engineering practice. However, the proportion of volatile matter can only qualitatively compare and analyze the ignition difficulty of different coal types, and cannot meet the requirements for quantitative analysis. Furthermore, the ignition temperature of blended coal cannot be simply obtained by weighted averaging the ignition temperatures of individual coal types. Experimentally testing the ignition point of blended coal is costly, time-consuming, and time-delayed, failing to meet the needs of coal-fired power plants for blending. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a method and system for predicting the ignition temperature of blended coal based on single coal thermogravimetric data, which addresses the above-mentioned problems in the prior art. This invention can predict the ignition temperature of blended coal with any blending ratio based on single coal thermogravimetric data. It has the advantages of convenient and fast prediction and high prediction accuracy. It can provide a reference for coal blending and combustion optimization, boiler furnace design, burner design and pulverizing system safety verification of coal-fired boilers, and also facilitate the intelligent management of coal blending and combustion in power plants.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for predicting the ignition temperature of blended coal based on single coal thermogravimetric data includes:

[0007] 1) The weighted average of the thermogravimetric data of each individual coal is used to obtain the thermogravimetric data curve (TG) of the blended coal. mix .

[0008] 2) Thermogravimetric analysis (TG) curves of mixed coal mix Differentiation yields the curve DTG mix Thermogravimetric analysis (TG) curves of mixed coal mix and curve DTG mix The ignition temperature IT of the mixed coal was obtained by graphical method. mix .

[0009] Optionally, in step 1), the weighted average of the thermogravimetric data of each individual coal refers to: weighting the thermogravimetric data of different individual coals according to their mass ratios to obtain the thermogravimetric data of the blended coal, thereby obtaining the thermogravimetric data curve TG of the blended coal composed of the thermogravimetric data of the blended coal. mix .

[0010] Optionally, the functional expression for obtaining the mass-weighted thermogravimetric data of the mixed coal is:

[0011]

[0012] In the above formula, c i Here are the thermogravimetric data of the mixed coal at temperature i, where R1 to Rk are the mixing mass ratios of the first to k types of single coal, respectively, and a 1i ~a ki The data are the thermal weight loss data for single coal types 1 to k, respectively, where k is the number of single coal types included in the blended coal.

[0013] Optionally, before obtaining the thermal weight loss data of the mixed coal by weighting the thermal weight loss data of different individual coals according to the mass ratio, the method further includes a step of testing each individual coal using a thermogravimetric analyzer to obtain the thermal weight loss data of each individual coal.

[0014] Optionally, in step 2), the ignition temperature IT of the mixed coal is obtained using a graphical method. mix Includes: DTG curve mix Draw a perpendicular line from the vertex of the minimum value, and intersect the TG curve of the mixed coal through this perpendicular line. mix Plot the thermogravimetric data curve TG at the intersection of the points. mix The tangent line is intersected with the thermogravimetric number curve TG. mix The temperature corresponding to the intersection of the initial horizontal lines is taken as the ignition temperature (IT) of the mixed coal. mix .

[0015] Optionally, step 2) may be followed by analyzing the thermogravimetric data curve TG. mix and curve DTG mixThe ignition temperature IT of the mixed coal was obtained by graphical method. mix The ignition temperature IT of the mixed coal was obtained by thermogravimetric analysis. mix-test Calculate the difference to obtain the deviation between the results of the graphical method and the test results of the thermogravimetric analyzer.

[0016] Optionally, step 1) also includes generating individual coal thermogravimetric curves (TG) based on the thermogravimetric data of each individual coal. j Differentiation yields the curve DTG j Thermogravimetric analysis (TG) curves of each individual coal j and curve DTG j The ignition temperature IT of each individual coal was obtained by graphical method. j .

[0017] Optionally, the ignition temperature IT of each individual coal is obtained using a graphical method. j At that time, the processing for any single coal j includes: processing the DTG curve of single coal j. j Draw a perpendicular line from the vertex of the minimum value, and intersect the thermogravimetric data curve TG of a single coal j through this perpendicular line. j Plot the thermogravimetric data curve TG at the intersection of the points. j The tangent line is intersected with the thermogravimetric number curve TG. j The temperature corresponding to the intersection of the initial horizontal lines is taken as the ignition temperature IT of single coal j. j .

[0018] Furthermore, the present invention also provides a system for predicting the ignition temperature of mixed coal based on single coal thermal weight loss data, comprising interconnected microprocessors programmed or configured to perform the steps of the method for predicting the ignition temperature of mixed coal based on single coal thermal weight loss data.

[0019] Furthermore, the present invention also provides a computer-readable storage medium storing a computer program for execution by a microprocessor to implement the steps of the method for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data.

[0020] Compared with the prior art, the present invention has the following main advantages: The method of the present invention for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data includes analyzing the thermogravimetric curve (TG) of the mixed coal. mix Differentiation yields the curve DTG mix ; For curve TG mix and DTG mix The ignition temperature IT of the mixed coal was obtained by graphical method. mixThis invention can predict the ignition temperature of blended coal with any blending ratio based on the thermal weight loss data of single coal. It has the advantages of convenient and fast prediction and high prediction accuracy. It can provide a reference for coal blending and combustion optimization, boiler furnace design, burner design and pulverizing system safety verification of coal-fired boilers, and also facilitate the intelligent management of coal blending and combustion in power plants. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the basic process of the method in Embodiment 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of the complete process of the method in Embodiment 1 of the present invention.

[0023] Figure 3 This is a schematic diagram illustrating the principle of obtaining the ignition temperature of mixed coal using a graphical method in Embodiment 1 of the present invention.

[0024] Figure 4 This is a schematic diagram illustrating the principle of obtaining the ignition temperature of coal type 1 using a graphical method in Embodiment 1 of the present invention.

[0025] Figure 5 This is a schematic diagram illustrating the principle of obtaining the ignition temperature of coal type 2 using a graphical method in Embodiment 1 of the present invention. Detailed Implementation

[0026] The following example, using a blended coal obtained by mixing two types of coal, type 1 and type 2, at a mass ratio of 1:1, will be used to illustrate the present invention in detail. It should be understood that the specific examples described herein are only for explaining the present invention and are not intended to limit the present invention. The present invention does not depend on a specific quantity of single coal or the specific type of single coal.

[0027] Example 1:

[0028] like Figure 1 As shown, the method for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data in this embodiment includes:

[0029] 1) The weighted average of the thermogravimetric data of each individual coal is used to obtain the thermogravimetric data curve (TG) of the blended coal. mix .

[0030] 2) Thermogravimetric analysis (TG) curves of mixed coal mix Differentiation yields the curve DTG mix Thermogravimetric analysis (TG) curves of mixed coal mix and curve DTG mix The ignition temperature IT of the mixed coal was obtained by graphical method. mix .

[0031] In this embodiment, step 1) of weighted averaging the thermogravimetric data of each individual coal refers to: weighting the thermogravimetric data of different individual coals according to their mass ratios to obtain the thermogravimetric data of the blended coal, thereby obtaining the thermogravimetric data curve TG of the blended coal composed of the thermogravimetric data of the blended coal. mix .

[0032] In this embodiment, the function expression for obtaining the thermogravimetric data of the mixed coal by weighting according to mass ratio is:

[0033]

[0034] In the above formula, c i Here are the thermogravimetric data for the mixed coal at temperature i, where R1 to Rk represent the mixing mass ratios of the first to k types of single coal (mixed according to the mass ratios R1:R2:…:Rk), and a 1i ~a ki These are the thermogravimetric data for single coal types 1 to k, respectively, where k is the number of single coal types included in the blend. Specifically, since this embodiment uses a blend of two single coal types, coal type 1 and coal type 2, the above function expression is as follows:

[0035]

[0036] In the above formula, R1 and R2 are the mixing mass ratios of coal type 1 and coal type 2, respectively. In this embodiment, coal type 1 and coal type 2 are mixed at a mass ratio of 1:1, so R1 and R2 are both taken as 1; a 1i ~a 2i The data are thermogravimetric data for coal type 1 and coal type 2, respectively.

[0037] See Figure 2 As a more complete data acquisition method, this embodiment includes a step of testing each individual coal using a thermogravimetric analyzer before obtaining the thermogravimetric data of the blended coal by weighting the thermogravimetric data of different individual coals according to mass ratios. The thermogravimetric data of any individual coal is obtained through thermogravimetric testing, which is a well-known method in the art, and its details will not be elaborated here. In this embodiment, the thermogravimetric dataset TG is composed of the thermogravimetric data of each individual coal j. j It can be represented as:

[0038] TG j =[a j1 ,a j2 ,…,a ji ,a j(i+1) ,…]

[0039] Thermogravimetric dataset TG jThe number can be determined based on the required temperature range and the number of temperature samples within that range. In this embodiment, the required temperature range is 100 to 1000 degrees Celsius.

[0040] In this embodiment, the ignition temperature IT of the mixed coal is obtained by graphical method in step 2). mix Includes: DTG curve mix Draw a perpendicular line from the vertex of the minimum value, and intersect the TG curve of the mixed coal through this perpendicular line. mix Plot the thermogravimetric data curve TG at the intersection of the points. mix The tangent line is intersected with the thermogravimetric number curve TG. mix The temperature corresponding to the intersection of the initial horizontal lines is taken as the ignition temperature (IT) of the mixed coal. mix See also Figure 3 As can be seen, in this embodiment, the ignition temperature of the mixed coal obtained by mixing two types of single coal, coal type 1 and coal type 2, in a mass ratio of 1:1 using the graphical method is 513.2℃.

[0041] As a more complete data acquisition method, step 2) also includes analyzing the thermogravimetric data curve (TG). mix and curve DTG mix The ignition temperature IT of the mixed coal was obtained by graphical method. mix The ignition temperature IT of the mixed coal was obtained by thermogravimetric analysis. mix-test The difference is calculated to obtain the deviation between the results of the graphical method and the test results of the thermogravimetric analyzer. Specifically, in this embodiment, the mixed coal is tested on the thermogravimetric analyzer, and the ignition temperature of the mixed coal is found to be 512.1℃. Therefore, the deviation between the results of the graphical method and the test results of the thermogravimetric analyzer is 1.1℃. As mentioned above, the ignition temperatures of coal type 1 and coal type 2 are 546.2℃ and 508.1℃, respectively. Therefore, the ignition temperature of the mixed coal is not a simple weighted average of the ignition temperatures of the individual coals. In this embodiment, the ignition temperature of the mixed coal obtained by weighted averaging of thermogravimetric data and then using the graphical method is closer to the test results of the thermogravimetric analyzer, resulting in more accurate detection results.

[0042] See Figure 2 As a more complete data acquisition method, step 1) in this embodiment also includes generating the thermogravimetric data curve (TG) of each individual coal unit, based on the thermogravimetric data of each coal unit. j Differentiation yields the curve DTG j Thermogravimetric analysis (TG) curves of each individual coal j and curve DTG j The ignition temperature IT of each individual coal was obtained by graphical method. j The ignition temperature IT of each individual coal was obtained using a graphical method. jAt that time, the processing for any single coal j includes: processing the DTG curve of single coal j. j Draw a perpendicular line from the vertex of the minimum value, and intersect the thermogravimetric data curve TG of a single coal j through this perpendicular line. j Plot the thermogravimetric data curve TG at the intersection of the points. j The tangent line is intersected with the thermogravimetric number curve TG. j The temperature corresponding to the intersection of the initial horizontal lines is taken as the ignition temperature IT of single coal j. j See also Figure 3 As can be seen, in this embodiment, the ignition temperature of coal type 1 is obtained as 546.2℃ using a graphical method. (See also...) Figure 4 As can be seen, in this embodiment, the ignition temperature of coal type 2 is 508.1℃ obtained by graphical method.

[0043] In summary, the method in this embodiment is based on the physical principle that the combustion process of mixed coal is a superposition of the combustion processes of individual coals; firstly, thermogravimetric analysis (TG) is performed on individual coals to obtain the TG data of each individual coal. j By analyzing the thermogravimetric data (TG) of each individual coal sample... j The thermal weight loss (TG) data of the mixed coal was calculated using a weighted average method. mix ; To TG mix After differentiation, we obtain DTG. mix The ignition temperature IT of the mixed coal was obtained by using a graphical method. mix The method in this embodiment utilizes the thermogravimetric analysis data of single coal to obtain the ignition temperature of blended coal with any blending ratio. This can guide the design and operation adjustment of boiler equipment and facilitate intelligent management of coal blending and combustion in power plants.

[0044] Furthermore, this embodiment also provides a system for predicting the ignition temperature of mixed coal based on single coal thermal weight loss data, including interconnected microprocessors that are programmed or configured to perform the steps of the method for predicting the ignition temperature of mixed coal based on single coal thermal weight loss data described above.

[0045] Furthermore, this embodiment also provides a computer-readable storage medium storing a computer program that is executed by a microprocessor to implement the steps of the method for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data described above.

[0046] Example 2:

[0047] This embodiment is basically the same as Embodiment 1, with the main difference being the method used to obtain the ignition temperatures of mixed coal and single coal using a graphical approach. A comparative analysis of Embodiment 1... Figures 3-5 Thermogravimetric Data Set of TG for Coal Mixtures mix Thermogravimetric Dataset for Single Coal (TG) j It can be observed that: for the derivative curve DTG mixDraw a perpendicular line from the vertex of the minimum value, and intersect the thermal weight loss dataset TG of the mixed coal through this perpendicular line. mix The intersection of the data with the thermogravimetric dataset of mixed coal (TG) mix Thermogravimetric Dataset for Single Coal (TG) j The median value (thermal weight loss curve TG) mix The initial horizontal line and the thermogravimetric number curve (TG) mix The midpoint of the horizontal line at the end is close to the position, so an approximation method can be used to obtain the ignition temperature IT of the mixed coal. mix / Ignition temperature of a single coal IT j : Thermogravimetric dataset TG of mixed coal mix Thermogravimetric Dataset for Single Coal (TG) j Find the median value, and then use the median value as the thermogravimetric dataset TG. mix Thermogravimetric Dataset for Single Coal (TG) j The tangent line is then compared with the thermogravimetric dataset TG. mix Thermogravimetric Dataset for Single Coal (TG) j The temperature corresponding to the intersection of the initial horizontal lines is taken as the ignition temperature (IT) of the mixed coal. mix / Ignition temperature of a single coal IT j Using the above method, it is not necessary to obtain the thermogravimetric dataset (TG) of the mixed coal. mix Thermogravimetric Dataset for Single Coal (TG) j Differentiation can further reduce the amount of computation, but since this method is an approximation, its accuracy will be somewhat worse than that of Example 1.

[0048] Furthermore, this embodiment also provides a system for predicting the ignition temperature of mixed coal based on single coal thermal weight loss data, including interconnected microprocessors that are programmed or configured to perform the steps of the method for predicting the ignition temperature of mixed coal based on single coal thermal weight loss data described above.

[0049] Furthermore, this embodiment also provides a computer-readable storage medium storing a computer program that is executed by a microprocessor to implement the steps of the method for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data described above.

[0050] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0051] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for predicting the ignition temperature of blended coal based on single coal thermogravimetric data, characterized in that, include: 1) The weighted average of the thermogravimetric data of each individual coal is used to obtain the thermogravimetric data curve (TG) of the mixed coal. mix； 2) Thermogravimetric analysis (TG) curves of mixed coal mix Differentiation yields the curve DTG mix Thermogravimetric analysis (TG) curves of mixed coal mix and curve DTG mix The ignition temperature IT of the mixed coal was obtained by graphical method. mix This includes: the thermogravimetric analysis (TG) curves of mixed coal. mix Take the median value and use it as an approximation of the curve DTG. mix After drawing a perpendicular line from the vertex of the minimum value, the curve of the thermal weight loss of the mixed coal intersects with the curve of the thermal weight loss of the mixed coal. mix The intersection point is used to plot the thermogravimetric data curve TG through this intermediate value. mix The tangent line is intersected with the thermogravimetric number curve TG. mix The temperature corresponding to the intersection of the initial horizontal lines is taken as the ignition temperature (IT) of the mixed coal. mix .

2. The method for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data according to claim 1, characterized in that, Step 1) involves weighting the thermogravimetric data of each individual coal group. This means weighting the thermogravimetric data of different individual coal groups according to their mass ratios to obtain the thermogravimetric data of the blended coal, thus creating the thermogravimetric data curve (TG) of the blended coal. mix .

3. The method for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data according to claim 2, characterized in that, The function expression for obtaining the mass-weighted thermogravimetric data of the mixed coal is as follows: In the above formula, c i The data represent the thermogravimetric analysis of the mixed coal at temperature i. R 1~ Rk They are respectively number 1 to k The mixing mass ratio of different types of coal, a 1i ~ a ki They are respectively number 1 to k Thermogravimetric data of single coal types, among which k This refers to the number of individual coal particles included in the mixed coal.

4. The method for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data according to claim 3, characterized in that, Before obtaining the thermogravimetric data of the mixed coal by weighting the thermogravimetric data of different individual coals according to the mass ratio, the method further includes the step of testing each individual coal using a thermogravimetric analyzer to obtain the thermogravimetric data of each individual coal.

5. The method for predicting the ignition temperature of blended coal based on single coal thermogravimetric data according to claim 1, characterized in that, Step 2) is followed by analyzing the thermogravimetric data curve (TG). mix and curve DTG mix The ignition temperature IT of the mixed coal was obtained by graphical method. mix The ignition temperature IT of the mixed coal was obtained by thermogravimetric analysis. mix-test Calculate the difference to obtain the deviation between the results of the graphical method and the test results of the thermogravimetric analyzer.

6. The method for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data according to claim 1, characterized in that, Step 1) also includes the individual coal thermogravimetric curves (TG) constructed from the thermogravimetric data of each individual coal. j Differentiation yields the curve DTG j Thermogravimetric analysis (TG) curves of each individual coal j and curve DTG j The ignition temperature IT of each individual coal was obtained by graphical method. j .

7. The method for predicting the ignition temperature of blended coal based on single coal thermogravimetric data according to claim 6, characterized in that, The ignition temperature IT of each single coal was obtained by graphical method. j At that time, the processing for any single coal j includes: processing the DTG curve of single coal j. j Draw a perpendicular line from the vertex of the minimum value, and intersect the thermogravimetric data curve TG of a single coal j through this perpendicular line. j Plot the thermogravimetric data curve TG at the intersection of the points. j The tangent line is intersected with the thermogravimetric number curve TG. j The temperature corresponding to the intersection of the initial horizontal lines is taken as the ignition temperature IT of single coal j. j .

8. A system for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data, comprising interconnected microprocessors, characterized in that, The microprocessor is programmed or configured to perform the steps of the method for predicting the ignition temperature of mixed coal based on single coal thermogravimetric data as described in any one of claims 1 to 7.

9. A computer-readable storage medium storing a computer program, characterized in that, The computer program is executed by a microprocessor to implement the steps of the method for predicting the ignition temperature of mixed coal based on single coal thermal weight loss data as described in any one of claims 1 to 7.

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