A method for calculating SO3 content in coal ash

Abstract

The application discloses a method for calculating the content of SO3 in coal ash, and comprises the following steps: preparing coal ash and determining the composition of the coal ash according to the test method of GB / T1574-2007; obtaining the coal quality parameters Aar and St,ar according to GB / T474-2008, GB / T211-2017, GB / T212-2008 and GB / T214-2007; calculating the conversion rate ZHLs of the sulfur in the coal into SO3 in the coal ash; and calculating the content of SO3 in the coal ash. The method is simple and fast, the research result is obtained by statistical analysis of a large number of laboratory test data, the discrimination precision is high, and the method has high engineering application value. The method can guide the design of the ash residue system of a newly-built power plant and the comprehensive utilization of fly ash.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization technology of coal and fly ash, specifically to a method for calculating the SO3 content in coal ash. Background Technology

[0002] The design of new generating units requires coal quality analysis of the design coal and the verification coal, including coal ash composition testing. The results of the coal ash composition test are used to analyze the slagging and fouling performance of the coal samples, and also to guide the design of the power plant ash system and the comprehensive utilization of fly ash.

[0003] In practical work, it was found that the SO3 content in the ash of some coal samples was significantly higher than that of the power plant's operating values. Therefore, ash samples were prepared from a large amount of raw coal using the following three methods: (1) A certain amount of analytical coal sample was burned and then cooled according to the preparation method of GB / T1574 to obtain ash samples; (2) Coal powder was burned in a one-dimensional flame furnace, and then fly ash was obtained in a cyclone (similar to a power plant ash silo); (3) Fly ash was obtained in an already operational power plant ash silo. The ash samples obtained by the three methods were tested for their ash composition. The results showed that when the content of alkaline oxides such as CaO and Fe2O3 in the ash was high, the SO3 content in the ash prepared by the GB / T1574 method was higher than that in the ash prepared by the one-dimensional flame furnace and the ash in the power plant ash silo. For this type of coal, the SO3 content obtained by testing the ash prepared by the GB / T1574 method cannot guide the comprehensive utilization of coal ash in power plants. However, it is obviously impractical to test the composition of fly ash by burning ash samples in actual large-scale pulverized coal boilers for all newly built units. Fly ash can also be burned by burning fly ash in a one-dimensional flame furnace, but this requires a lot of labor and time costs. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a method for calculating the SO3 content in coal ash, applicable to anthracite, lean coal, bituminous coal, long-flame coal and lignite.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for calculating the SO3 content in coal ash includes the following steps:

[0007] Step 1: Prepare coal ash samples and determine their composition;

[0008] Step 2: Obtain coal quality parameters, specifically including received ash content (Aar, %) and total sulfur content (St,ar, %).

[0009] Step 3: Calculate the conversion rate ZHLs (%) of sulfur in coal to SO3 in coal ash;

[0010] Step 4: Calculate SO in coal ash 3jContent, %, see formula (2) for specific calculation method.

[0011] SO 3j =2.5×ZHLs / Aar (2)

[0012] Step 5: Based on the comparison of SO 3j The magnitude of SO3 was used to ultimately determine the SO content in the coal ash. 3Z ;

[0013] SO 3j ≥SO3, SO 3Z =SO3; conversely, SO 3j <SO3,SO 3Z =SO3 j .

[0014] A further improvement of the present invention is that, in the first step, the coal ash composition includes SO3, SiO2, Al2O3, Fe2O3, CaO and MgO.

[0015] A further improvement of this invention is that ZHLs reveal the adsorption efficiency of key coal ash components SiO2, Al2O3, Fe2O3, CaO, and MgO on SO3 during the testing process.

[0016] A further improvement of the present invention is that, in the first step, coal ash sample preparation and coal ash composition determination are carried out in accordance with the test method of GB / T1574-2007.

[0017] A further improvement of the present invention is that, in the second step, coal quality parameters are obtained in accordance with GB / T474-2008 "Methods for Preparation of Coal Samples", GB / T211-2017 "Methods for Determination of Total Moisture in Coal", GB / T212-2008 "Industrial Analysis Methods for Coal", and GB / T214-2007 "Methods for Determination of Total Sulfur in Coal".

[0018] A further improvement of this invention is that, in the third step, the specific calculation method for the conversion rate ZHLs is given in equation (1).

[0019] ZHLs=1.649×SiO2-0.015×Al2O3+2.365×Fe2O3+1.463×CaO+0.521×MgO-104.441(1).

[0020] A further improvement of the present invention is that, in the fifth step, based on the comparison of SO... 3j The magnitude of SO3 was used to ultimately determine the SO content in the coal ash. 3Z .

[0021] A further improvement of the present invention is that the method is applicable to anthracite, lean coal, bituminous coal, long-flame coal and lignite.

[0022] A further improvement of this invention is that it deduces the SO3 content of coal ash during the actual combustion process based on the ash composition of different coal types, thus fully restoring the ash-making process of coal samples during actual combustion in power plant pulverized coal boilers.

[0023] The present invention has at least the following beneficial technical effects:

[0024] By using existing experimental methods to test coal quality parameters and ash composition, the SO3 content of fly ash in ash storage can be predicted, and this value is very close to the value in the actual production process of power plants. This can guide the comprehensive utilization of fly ash. ② There is no need to prepare fly ash in large pulverized coal boilers or one-dimensional flame combustion furnaces in laboratories, saving a lot of manpower, material resources, and financial resources. ③ This result is obtained through statistical analysis of test results from a large number of field samples and laboratory samples, with high calculation accuracy and high engineering application value. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to specific embodiments.

[0026] Example 1 - Calculation of SO3 content in coal ash of Sample 1

[0027] Step 1: Prepare coal ash samples and determine the composition (SiO2, Al2O3, Fe2O3, CaO, MgO) of coal ash according to the test method of GB / T1574-2007;

[0028] The coal ash composition results for Sample 1 are as follows:

[0029] SO3=14.20%, SiO2=27.89%, Al2O3=10.88%, Fe2O3=24.86%, CaO=9.87%,

[0030] MgO = 4.45%

[0031] Step 2: Obtain coal quality parameters according to GB / T474-2008 "Preparation Method of Coal Samples", GB / T211-2017 "Determination of Total Moisture in Coal", GB / T212-2008 "Industrial Analysis Method of Coal", and GB / T214-2007 "Determination of Total Sulfur in Coal", specifically including ash content Aar (%) and total sulfur St,ar (%) on an as-received basis.

[0032] The results of the received basis ash content (Aar) and total sulfur content (St,ar) of sample 1 are as follows:

[0033] Aar=7.83%, St,ar=0.62%

[0034] Step 3: Calculate the conversion rate ZHLs (%) of sulfur in coal to SO3 in coal ash. For the specific calculation method, please refer to Equation (1).

[0035] ZHLs = 1.649×SiO2 - 0.015×Al2O3 + 2.365×Fe2O3 + 1.463×CaO + 0.521×MgO - 104.441(1)

[0037] The conversion rate ZHLs (%) of SO3 in the coal ash of Sample 1

[0038] ZHLs = 1.649×SiO2 - 0.015×Al2O3 + 2.365×Fe2O3 + 1.463×CaO + 0.521×MgO -

[0039] 104.441 = 1.649×27.89 - 0.015×10.88 + 2.365×24.86 + 1.463×9.87 + 0.521×4.45 - 104.441 = 16.94

[0040] Step 4: Calculate the SO3 content (%) in the coal ash. The specific calculation method is shown in Equation (2).

[0041] SO 3j = 2.5×ZHLs / Aar (2)

[0042] The calculation of the SO3 content in the coal ash of Sample 1 is as follows:

[0043] SO 3j = 2.5×16.94 / Aar = 2.5×16.94 / 7.83 = 5.41

[0044] Step 5: Based on comparing the magnitudes of SO 3j and SO3, finally determine the SO 3Z ;

[0045] SO 3j ≥SO3, SO 3Z = SO3; conversely, SO 3j <SO3, SO 3Z = SO3 j ;

[0046] SO 3j of Sample 1 = 5.41 < SO3 = 14.20, then the finally determined SO 3Z in the coal ash = SO3 j = 5.41;

[0047] The SO3 content in the coal ash of the sample obtained by the method of the present invention is 5.41%. The SO3 detection results in the power plant ash storage ash and the one-dimensional flame furnace cyclone ash are 5.56% and 5.37% respectively, and the results are very close.

[0048] Example 2 - Calculation of SO3 content in coal ash of sample 2

[0049] Step 1: Prepare coal ash samples and determine the composition (SiO2, Al2O3, Fe2O3, CaO, MgO) of coal ash according to the test method of GB / T1574-2007;

[0050] The coal ash composition results for sample 2 are as follows:

[0051] SO3=8.20%, SiO2=31.39%, Al2O3=14.65%, Fe2O3=11.94%, CaO=26.16%,

[0052] MgO = 2.62%

[0053] Step 2: Obtain coal quality parameters according to GB / T474-2008 "Preparation Method of Coal Samples", GB / T211-2017 "Determination of Total Moisture in Coal", GB / T212-2008 "Industrial Analysis Method of Coal", and GB / T214-2007 "Determination of Total Sulfur in Coal", specifically including ash content Aar (%) and total sulfur St,ar (%) on an as-received basis.

[0054] The results of the received basis ash content (Aar) and total sulfur content (St,ar) of sample 2 are as follows:

[0055] Aar=4.67%, St,ar=0.14%

[0056] Step 3: Calculate the conversion rate ZHLs (%) of sulfur in coal to SO3 in coal ash. For the specific calculation method, please refer to Equation (1).

[0057] ZHLs=1.649×SiO2-0.015×Al2O3+2.365×Fe2O3+1.463×CaO+0.521×MgO- 104.441(1)

[0059] The SO3 conversion rate ZHLs (%) in the coal ash of Sample 2.

[0060] ZHLs=1.649×SiO2-0.015×Al2O3+2.365×Fe2O3+1.463×CaO+0.521×MgO-

[0061] 104.441 = 1.649 × 31.39 - 0.015 × 14.65 + 2.365 × 11.94 + 1.463 × 26.16 + 0.521 × 2.62 - 104.441 = 14.98

[0062] Step 4: Calculate the SO3 content (%) in coal ash. The specific calculation method is shown in Equation (2).

[0063] SO3 j = 2.5 × ZHLs / Aar (2)

[0064] The calculation of the SO3 content in the coal ash of Sample 2 is as follows:

[0065] SO3 j = 2.5 × 16.94 / Aar = 2.5 × 14.98 / 4.67 = 8.02

[0066] Step 5: Finally determine the SO in the coal ash according to the comparison of the magnitudes of SO 3j and SO3; 3Z ;

[0067] SO 3j ≥ SO3, SO 3Z = SO3; otherwise, SO 3j < SO3, SO 3Z = SO3 j [[ID=3三十三]];

[0068] The SO 3j of Sample 2 = 8.02 < SO3 = 8.20, then the finally determined SO in the coal ash 3Z = SO3 j = 8.02;

[0069] The SO3 content in the coal ash of the sample obtained by the method of the present invention is 8.02%. The SO3 detection results in the power plant ash storage ash and the one-dimensional flame furnace cyclone ash are 7.89% and 8.00% respectively, and the results are very close.

[0070] Example 3 - Calculation of the SO3 content in the coal ash of Sample 3

[0071] Step 1: Prepare the coal ash sample and determine the coal ash composition (SiO2, Al2O3, Fe2O3, CaO, MgO) according to the test method of GB / T1574 - 2007;

[0072] The results of the coal ash composition of Sample 3 are as follows:

[0073] SO3 = 3.30%, SiO2 = 57.25%, Al2O3 = 18.01%, Fe2O3 = 7.45%, CaO = 5.93%,

[0074] 0MgO = 1.91%

[0075] Step 2: Obtain coal quality parameters according to GB / T474-2008 "Preparation Method of Coal Samples", GB / T211-2017 "Determination of Total Moisture in Coal", GB / T212-2008 "Industrial Analysis Method of Coal", and GB / T214-2007 "Determination of Total Sulfur in Coal", specifically including ash content Aar (%) and total sulfur St,ar (%) on an as-received basis.

[0076] The results of the received basis ash content (Aar) and total sulfur content (St,ar) of sample 3 are as follows:

[0077] Aar=15.58%, St,ar=0.21%

[0078] Step 3: Calculate the conversion rate ZHLs (%) of sulfur in coal to SO3 in coal ash. For the specific calculation method, please refer to Equation (1).

[0079] ZHLs=1.649×SiO2-0.015×Al2O3+2.365×Fe2O3+1.463×CaO+0.521×MgO- 104.441(1)

[0081] The SO3 conversion rate ZHLs (%) in the coal ash of sample 3.

[0082] ZHLs=1.649×SiO2-0.015×Al2O3+2.365×Fe2O3+1.463×CaO+0.521×MgO-

[0083] 104.441 = 1.649 × 57.25 - 0.015 × 18.01 + 2.365 × 7.45 + 1.463 × 5.93 + 0.521 × 1.91 - 104.441 = 16.98

[0084] Step 4: Calculate the SO3 content (%) in the coal ash. For the specific calculation method, please refer to formula (2).

[0085] SO3 j =2.5×ZHLs / Aar (2)

[0086] The SO3 content in the coal ash of sample 3 was calculated as follows:

[0087] SO3 j =2.5×16.94 / Aar=2.5×16.98 / 15.58=2.72

[0088] Step 5: Based on the comparison of SO 3j The magnitude of SO3 was used to ultimately determine the SO content in the coal ash. 3Z ;

[0089] SO3j ≥SO3, SO 3Z =SO3; conversely, SO 3j <SO3, SO 3Z =SO3 j ;

[0090] SO of Sample 3 3j =2.72 <SO3 = 3.30, then the finally determined SO in the coal ash 3Z =SO3 j =2.72;

[0091] The SO3 content in the coal ash of the sample obtained by the method of the present invention is 2.72%. The detection results of SO3 in the ash in the power plant ash bunker and the cyclone ash of the one-dimensional flame furnace are 2.69% and 2.81% respectively, and the results are very close.

[0092] Although the present invention has been described in detail above with general descriptions and specific embodiments, on the basis of the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A method for calculating the SO3 content in coal ash, characterized in that, Includes the following steps: Step 1: Prepare coal ash samples and determine the composition of the coal ash, which includes SO3, SiO2, Al2O3, Fe2O3, CaO and MgO; Step 2: Obtain coal quality parameters, including received basis ash content (Aar, %) and total sulfur content (St,ar, %). Step 3: Calculate the conversion rate ZHLs, of sulfur in coal to SO3 in coal ash; for the specific calculation method of conversion rate ZHLs, please refer to formula (1). ZHLs=1.649×SiO2-0.015×Al2O3+2.365×Fe2O3+1.463×CaO+0.521×MgO-104.441 (1) In the formula, SiO2, Al2O3, Fe2O3, CaO, and MgO represent the content of coal ash components, expressed in % (%). Step 4: Calculate SO in coal ash 3j Content, %, see formula (2) for specific calculation method. SO 3j =2.5×ZHLs / Year(2) Step 5: Based on the comparison of SO 3j The magnitude of SO3 was used to ultimately determine the SO content in the coal ash. 3Z SO 3j ≥SO3, SO 3Z = SO3; conversely, SO 3j <SO3,SO 3Z = SO 3 j .

2. The method for calculating SO3 content in coal ash according to claim 1, characterized in that, In the first step, coal ash samples were prepared and the composition of coal ash was determined in accordance with the test methods of GB / T1574-2007.

3. The method for calculating the SO3 content in coal ash according to claim 1, characterized in that, In the second step, coal quality parameters are obtained in accordance with GB / T474-2008 "Methods for Preparation of Coal Samples", GB / T211-2017 "Methods for Determination of Total Moisture in Coal", GB / T212-2008 "Industrial Analysis Methods for Coal", and GB / T214-2007 "Methods for Determination of Total Sulfur in Coal".

4. The method for calculating the SO3 content in coal ash according to claim 1, characterized in that, This method can be used for anthracite, lean coal, bituminous coal, long-flame coal and lignite.