A method for judging the explosion properties of pulverized coal

Abstract

The present invention discloses a method for determining the explosion performance of coal powder, comprising the steps of: 1. obtaining the total moisture content M of the coal; t (%), received ash content A ar (%), received volatile matter V ar (%), dry ash-free low calorific value Q net,daf (KJ / kg); 2. Calculate the coal powder explosion index K d ; 3. Calculate the moisture correction coefficient K1 and the volatile matter correction coefficient K2; 4. Calculate the final coal powder explosion index KK d , and determine the explosion properties of coal samples. This invention derives a pulverized coal explosion index based on the explosion behavior of different coal types during actual power plant operation, which more closely matches actual operating conditions. The grading of pulverized coal explosion properties is also more detailed, with greater engineering application value. It can be used to guide explosion prevention in pulverized coal production systems in thermal power plants, contributing to improved operational safety.

Description

Technical Field

[0001] The invention relates to the technical field of coal powder explosion performance, in particular to a method for judging coal powder explosion performance, which is applicable to anthracite, lean coal, bituminous coal and lignite. Background Art

[0002] The coal powder explosion index K is specified in the power industry standard "DL / T466-2017 Guidelines for Selection of Power Plant Coal Mills and Pulverizing Systems". d However, in Zhang Jianzhong's "Analysis on Several Issues in the Calculation, Formulation and Use of Explosion Index of Coal Types in Thermal Power Plants", the calculation method and classification standard of pulverized coal explosion index K d Some existing problems were raised. In general, according to the K d The calculation results can roughly reflect the explosion tendency of different types of coal from anthracite to lignite. Combined with the actual explosion of different types of coal in power plants, it is found that this indicator also has some shortcomings: it tends to classify long flame coal that is prone to explosion in actual operation as "relatively easy" or "medium". In addition, during the classification process, most bituminous coal and lignite with better combustion performance are judged as "relatively easy" to explode, and the K of some lignite is not good. d The value is not as high as that of bituminous coal, and there is a certain deviation from the actual operating results. Summary of the Invention

[0003] In order to overcome the shortcomings of the above-mentioned prior art, the present invention relates to the technical field of coal powder explosion performance, and specifically to a method for judging coal powder explosion performance, which is applicable to anthracite, lean coal, bituminous coal and lignite.

[0004] To achieve the above object, the present invention adopts the following technical solution, and the specific steps are as follows:

[0005] A method for determining the explosion properties of pulverized coal, which is applicable to anthracite, lean coal, bituminous coal and lignite, comprises the following steps:

[0006] Step 1: Obtain the total moisture content of coal M t , received basic ash A ar , dry ash-free volatile matter V daf , dry ash-free low calorific value Q net,daf , where the total moisture content of coal M t , received basic ash A ar and dry ash-free volatile matter V daf The unit is %, dry ash-free low calorific value Q net,daf The unit is KJ / kg;

[0007] Step 2: Calculate the coal powder explosion index K d ;

[0008] Step 3: Calculate the moisture correction coefficient K1 and the volatile matter correction coefficient K2;

[0009] Step 4: Calculate the corrected coal powder explosion index KK d , see formula (9) for details:

[0010] KK d =K1×K2×K d (Equation 9)

[0011] Step 5: Classify the coal powder explosion characteristics:

[0012]

[0013]

[0014] A further improvement of the present invention is that the coal powder explosion index K d The calculation formula is:

[0015]

[0016] A further improvement of the present invention is that

[0017]

[0018] A further improvement of the present invention is that

[0019]

[0020] A further improvement of the present invention is that

[0021]

[0022] A further improvement of the present invention is that

[0023]

[0024] A further improvement of the present invention is that

[0025] FC daf =100-V daf (Formula 6).

[0026] A further improvement of the present invention is that the calculation formulas for the moisture correction coefficient K1 and the volatile matter correction coefficient K2 are:

[0027]

[0028]

[0029] The present invention has at least the following beneficial technical effects:

[0030] The invention provides a method for judging the explosion performance of coal powder, which is applicable to anthracite, lean coal, bituminous coal and lignite.

[0031] The advantages of the present invention are: ① According to the explosion conditions of different types of coal in the actual operation of the power plant, a new coal powder explosion index KK is obtained d ② This index accurately reflects the explosion propensity of different coal types and is more consistent with actual operating conditions. ② It provides a more detailed classification of the pulverized coal explosion index, which has higher engineering application value. ③ It can be used to guide the explosion prevention of power plant pulverizing systems, which is conducive to improving the safety of power plant operations. DETAILED DESCRIPTION

[0032] The exemplary embodiments of the present disclosure will be described in more detail below. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0033] Example 1 - Calculation of the pulverized coal explosion index KKd of sample 1 (a type of lignite) and evaluation of pulverized coal explosion

[0034] The present invention will be further described in detail below with reference to the embodiments.

[0035] Step 1: Obtain the total moisture content of coal M t (%), received ash content A ar (%), dry ash-free basis volatile matter V daf (%), dry ash-free low calorific value Q net,daf (KJ / kg);

[0036] A lignite M t =36.60%, received base ash A ar =7.74%, volatile matter on dry ash-free basis V daf =45.30%, dry ash-free low calorific value Q net,daf =25689KJ / kg

[0037] Step 2: Calculate the coal powder explosion index K d , see formula (1) to formula (6) for details

[0038]

[0039]

[0040]

[0041]

[0042]

[0043] FC daf =100-V daf =100-39.62=54.70 (Formula 6)

[0044] Step 3: Calculate the moisture correction coefficient K1 and the volatile matter correction coefficient K2, as shown in formula (7) and formula (8):

[0045]

[0046]

[0047] V of sample 1 daf >25%, and M t >10%, so

[0048]

[0049] Sample 1 so

[0050]

[0051] Step 4: Calculate the corrected coal powder explosion index KK d , see formula (9) for details

[0052] KK d =K1×K2×K d =1.91×2.46×2.38=11.17 (Equation 9)

[0053] Step 5: Classify the coal powder explosion characteristics:

[0054]

[0055]

[0056] KK of sample 1 d =11.17>10, according to the classification standard in the table, it belongs to Class III extremely explosive coal. According to the calculation results of "DL / T466-2017", the K d The KK of typical domestic coal is also listed in the table below. d and K d The calculation results and the results of coal powder explosion tendency are shown in K d The index tends to underestimate the explosion tendency of lignite. It can be seen that the method of the present invention can better reflect the actual explosion tendency of different types of coal.

[0057]

[0058]

[0059]

[0060] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A method for determining the explosion properties of coal dust, characterized in that: The method is applicable to anthracite, lean coal, bituminous coal and lignite, and comprises the following steps: Step 1: Obtain the total moisture content of coal M t , received basic ash A ar , dry ash-free volatile matter V daf , dry ash-free low calorific value Q net,daf , where the total moisture content of coal M t , received basic ash A ar and dry ash-free volatile matter V daf The unit is %, dry ash-free low calorific value Q net,daf The unit is KJ / kg; Step 2: Calculate the coal powder explosion index K d , the calculation formula is: FC daf = 100 - V daf (Equation 6) Step 3: Calculate the moisture correction coefficient K1 and the volatile matter correction coefficient K2. The calculation formula is: Step 4: Calculate the corrected coal powder explosion index KK d , see formula (9) for details: KK d =K1×K2×K d (Equation 9) Step 5: According to KK d The numerical values ​​are used to divide the coal powder explosion characteristics as follows: When KK d When <0.5, the coal dust explosion level is classified as extremely difficult; When 0.5≤KK d When <1.0, it is difficult to classify the coal dust explosion level; When 1.0≤KK d When <2.2, the coal dust explosion level is classified as difficult; When 2.2≤KK d When <3.5, the coal dust explosion level is classified as easy; When 3.5≤KK d When <5.0, the coal dust explosion level is classified as Level I, extremely easy; When 5.0≤KK d When the value is less than 10, the coal dust explosion level is classified as Level II, extremely easy; When 10≤KK d When the coal dust explosion level is classified as level III, it is extremely easy.

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