A preparation method of a comprehensive sample for calculating the content of coal combustion element carbon

Abstract

The application discloses a preparation method of a comprehensive sample for accounting for element carbon content of coal, obtains particle sizes of each sample for measuring element carbon content of coal, parameter information of corresponding coal into a furnace of each sample and weight of each sample in an air dry state, calculates calibrated air dry base moisture of each sample according to the parameter information of the corresponding coal into the furnace of each sample and the weight of each sample in the air dry state, further calculates air dry base conversion sample amount of raw coal of the corresponding coal into the furnace of each sample, calculates mass fraction of each sample when the comprehensive sample is combined according to the air dry base conversion sample amount of the raw coal of the corresponding coal into the furnace of each sample, combines each sample according to the mass fraction of each sample when the comprehensive sample is combined, and obtains the comprehensive sample. The application determines a method for combining a proportion of the comprehensive sample for accounting for element carbon content of coal, has high practical applicability, a simple calculation process, accurate results and high practical application value, and provides a basis for accurately accounting for element carbon content of coal.

Description

Technical Field

[0001] This invention belongs to the field of coal sample collection technology in thermal power plants, and specifically relates to a method for preparing a comprehensive sample for calculating the elemental carbon content of coal. Background Technology

[0002] For coal-fired power plants, the fossil fuel used is coal. When calculating carbon dioxide emissions from coal combustion during the statistical period, the coal consumption is measured by measuring the amount of coal fed into the furnace using a calibrated belt scale or pressure-resistant metering feeder. The elemental carbon content of the coal can be obtained using one of three methods: 1) daily testing; 2) batch testing; 3) monthly reduced-sample testing. The elemental carbon content of the coal should be tested by a testing institution or laboratory accredited by CMA or CNAS, with elemental carbon content included in their accreditation. Methods 1) daily testing and 2) batch testing involve large daily sample volumes to external testing institutions, significantly increasing costs, long testing cycles, and low efficiency, which is detrimental to actual fuel production management. Therefore, currently, thermal power plants mainly use method 3) monthly reduced-sample testing to calculate the monthly elemental carbon content of coal. This involves merging and mixing daily coal samples collected into a monthly test sample to determine the elemental carbon content of the coal.

[0003] The "Guidelines for Enterprise Greenhouse Gas Emission Accounting Methods and Reporting for Power Generation Facilities (2022 Revised Edition)" clearly states that when merging monthly reduced sample tests, the mass of each reduced sample should be proportional to the mass of the raw coal fed into the furnace before merging and the baseline should remain consistent. However, in practical applications, the commonly used baselines for coal samples are received basis and air-dried basis. Received basis refers to the original state of the coal. The nominal maximum particle size of coal fed into the furnace is generally 25mm or larger. The received basis quantity for a 25mm coal sample must be no less than 40kg. Taking 5 coal samples fed into the furnace daily as an example, the amount of original state coal sample to be preserved must be no less than 200kg, resulting in a monthly raw coal quantity of nearly 6000kg, which is impractical and difficult to store. Furthermore, the large particle size of the received basis coal sample requires further sample preparation and crushing to a smaller particle size before sample reduction. This crushing process easily leads to total moisture loss, causing a deviation from the received basis baseline. Air-dried basis refers to the state of the coal sample when a certain particle size reaches equilibrium with air humidity. Coal samples under air-dried conditions include general analytical samples with a particle size of 0.2 mm and reference samples with a particle size of 3 mm. Due to their small particle size, the 0.2 mm general analytical samples are prone to oxidation and deterioration during the one-month storage period, which can lead to deviations in test results. Therefore, thermal power plants currently obtain their monthly reduced coal sample by merging and mixing the 3 mm reference samples. The 3 mm reference sample typically weighs 700g–900g, making it easy to store and manage. Thermal power plants use the weighted average of the 3 mm reference samples from daily coal inputs, calculated according to the proportion of daily raw coal inputs to the monthly total, to generate the monthly reduced sample for calculating the carbon content of the coal. However, the baseline of the 3 mm reference sample is not consistent with that of the raw coal sample, especially when the external moisture content of the daily raw coal samples varies significantly. This results in a large deviation in the merging ratio, leading to discrepancies between the calculated elemental carbon content of the monthly merged sample and the actual emissions. Summary of the Invention

[0004] To overcome the technical problem in the prior art that the calculated elemental carbon content of monthly combined samples does not match the actual emissions, the purpose of this invention is to provide a method for preparing a comprehensive sample for calculating the carbon content of coal. The comprehensive sample prepared by this method can accurately calculate the calculated elemental carbon content of monthly combined samples, so that the calculated elemental carbon content of monthly combined samples is consistent.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a comprehensive sample for calculating the elemental carbon content of coal includes the following steps:

[0007] The particle size of each sample used to determine the elemental carbon content of coal, the parameter information of the coal fed into the furnace corresponding to each sample, and the weight of each sample under air-dried conditions were obtained and merged.

[0008] Based on the parameter information of the coal fed into the furnace corresponding to each sample and the weight of each sample under air-dried conditions, calculate the calibrated air-dried basis moisture content of each sample when merging the comprehensive sample.

[0009] Based on the calibrated air-dried basis moisture content of each sample, calculate the corresponding air-dried basis equivalent sample quantity of raw coal entering the furnace for each sample.

[0010] Based on the air-dried basis of the raw coal entering the furnace corresponding to each sub-sample, calculate the mass fraction of each sub-sample when merging the comprehensive sample.

[0011] Based on the mass fraction of each sample when merging the composite sample, the samples are combined to obtain the composite sample.

[0012] Furthermore, the particle size of each sample is 3 mm or 0.2 mm.

[0013] Furthermore, the parameter information for the coal fed into the furnace corresponding to each sample includes the raw coal consumption (m) for each sample. i The corresponding received moisture content M of the coal fed into the furnace ar,i， Air-dried basis moisture content M of each sample ad,i and the original weight m of each sample s,i .

[0014] Furthermore, the weight of each sample under air-dried conditions is the weight of each sample when it is placed in air at room temperature to reach an air-dried state.

[0015] Furthermore, the air-drying state refers to the air-drying state achieved by placing each sample in an air-conditioned environment at room temperature according to the GB / T474 standard method.

[0016] Furthermore, the calibration air-dried basis moisture content of each sample was... Calculated using the following formula:

[0017]

[0018] In the formula, The weight of each sample under air-dried conditions, m s,i The original weight of each sample.

[0019] Furthermore, based on the calibration air-dried basis moisture content of each sample, the corresponding air-dried basis equivalent sample quantity of raw coal entering the furnace for each sample is calculated, including the following steps:

[0020] Calculate the surface moisture of the raw coal fed into the furnace corresponding to each sample based on the calibration air-dried basis moisture content.

[0021] Based on the surface moisture content of the raw coal entering the furnace corresponding to each sub-sample, calculate the air-dried basis equivalent sample quantity of the raw coal entering the furnace corresponding to each sub-sample.

[0022] Furthermore, the surface moisture content M of the raw coal fed into the furnace corresponding to each sample was... s.i Calculated using the following formula:

[0023]

[0024] M s.i —Surface moisture content of the i-th raw coal sample fed into the furnace, in %;

[0025] M ar,i —Moisture content of the i-th raw coal sample received, in %;

[0026] —Moisture content of each sample on the calibration air-dried basis when combining the composite samples, in %;

[0027] i — the number of samples.

[0028] Furthermore, the air-dried basis equivalent sample quantity (m) of the raw coal fed into the furnace corresponding to each subsample is calculated. zs,i Calculated using the following formula:

[0029] m zs,i =m i ×(100-M s,i ) / 100

[0030] In the formula, m i m represents the raw coal consumption for each sample entering the furnace. s,i The original weight of each sample.

[0031] Furthermore, when merging the composite sample, the mass fraction w of each sample... i Calculated using the following formula:

[0032]

[0033] In the formula, m zs,i The air-dried basis of the raw coal entering the furnace is converted into the sample quantity for each subsample.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] First, using the coal sample for testing in the furnace to reduce and combine carbon emission comprehensive test samples is more practically feasible than using the raw coal sample. The amount of sample to test is less than that of the raw coal sample, which greatly reduces the storage volume and makes it easier to store. The process of reducing and combining the samples is easier to operate in practice than mixing the raw coal sample, and the uniformity is higher.

[0036] Second, the calculation process is simple. The surface moisture content is calculated by using the air-dried and received moisture parameters of the general analytical sample. The calculation is simple and the method is reliable.

[0037] Third, the results are accurate. Before merging the composite samples, each sample is air-dried to a dry state. This avoids the influence of changes in moisture content on the sample basis caused by changes in ambient temperature during the preparation of the composite sample. The method ensures that the baseline of each fraction of coal entering the furnace remains consistent before merging. Compared to the guideline requirement that the mass of each fraction should be proportional to the mass of the raw coal sample entering the furnace, with the baseline being the received basis, this method, after each sample reaches a dry state, calculates the sample volume of the raw coal sample entering the furnace under the hypothetical air-dried condition, thus achieving an accurate calculation of the merging ratio and providing a basis for accurately calculating the elemental carbon content of coal. Detailed Implementation

[0038] To facilitate understanding of the present invention, a more comprehensive description is provided below. Conversely, these embodiments are provided so that a thorough and complete understanding of the disclosure of the present invention may be achieved.

[0039] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0040] The present invention provides a method for preparing a comprehensive sample for calculating elemental carbon content, comprising the following steps:

[0041] Step 1: Determine the particle size of each subsample of the combined air-dried basis sample used for determining the elemental carbon content of coal, either 3 mm or 0.2 mm;

[0042] Step 2: Collect the corresponding raw coal consumption (m) for each sample. i The corresponding received moisture content M of the coal fed into the furnace ar,i The air-dried basis moisture content (M) of each sample at that time ad,i The weight of each sample at that time, i.e., the original weight m of each sample. s,i ;

[0043] Step 3: On the day of merging the composite samples, place each subsample in an air-dried environment at room temperature according to the GB / T474 standard method until it reaches an air-dried state, and record the weight of each subsample at this time, i.e., the weight of each subsample under air-dried conditions.

[0044] Step 4: Based on the original weight of each sample and the weight of each sample under air-dried conditions, calculate the calibration air-dried basis moisture content of each sample on the day of merging and synthesizing the sample.

[0045]

[0046] Step 5: Based on the calibration air-dried basis moisture content of each sample, calculate the surface moisture content M of the raw coal entering the furnace for each sample using the following formula. s.i ,

[0047]

[0048] M s.i —Surface moisture content of the i-th raw coal sample fed into the furnace, in %;

[0049] M ar,i —Moisture content of the i-th raw coal sample received, in %;

[0050] —Moisture content of each sample on the calibration air-dried basis when combining the composite samples, in %;

[0051] i — the number of samples.

[0052] Step 6: Based on the surface moisture content of the raw coal entering the furnace for each sample, calculate the air-dried basis equivalent sample quantity (m) of the raw coal entering the furnace for each sample using the following formula. zs,i :

[0053] m zs,i =m i ×(100-M s,i ) / 100

[0054] Step 7: Based on the air-dried basis of the raw coal corresponding to each sub-sample, calculate the mass fraction w of each sub-sample when merging the composite sample. i :

[0055]

[0056] The following are specific examples.

[0057] Example 1: Calculate the proportion of each sample in the monthly carbon emission verification comprehensive sample of 3mm coal used daily in a power plant for inspection.

[0058] (1) Step 1: The particle size of each sample used for merging the monthly carbon emission verification air-dried basis composite sample is 3 mm;

[0059] (2) Second step: There are two days' worth of 3mm coal samples for inspection in the current month, that is, there are two sub-samples, and the corresponding raw coal consumption m for the two sub-samples is...i The corresponding received moisture content M of the coal fed into the furnace ar,i， The air-dried basis moisture content (M) of the two samples at the time of sampling ad,i The weights m of the two samples at that time s,i See the table below;

[0060]

[0061] (3) Third step: On the day of merging the composite samples, place each sample in an air-dried state at room temperature according to the GB / T474 standard method, and record the weight of the two samples when they reach the air-dried state. See the table below;

[0062]

[0063] (4) Step 4: Calculate the moisture content of the two samples on the calibration air-dried basis on the day of merging the composite sample. Moisture content of the first sample on a calibration air-dried basis:

[0064]

[0065] Moisture content of the second sample on a calibration air-dried basis:

[0066]

[0067] (5) Step 5: Calculate the surface moisture M of the raw coal entering the furnace corresponding to the two samples. s.i ,

[0068] The surface moisture content (M) of the first batch of raw coal fed into the furnace s.1 :

[0069] The surface moisture content M of the second batch of raw coal fed into the furnace s.2 : (6) Step 6: Calculate the air-dried basis equivalent sample quantity (m) of the raw coal entering the furnace corresponding to the two samples. zs,i :

[0070] The first batch of coal fed into the furnace, calculated on an air-dried basis, in m³. zs,1 :m zs,1 =m1×(100-M) s,1 ) / 100

[0071] =2000×(100-1.05) / 100

[0072] =1979.00(t)

[0073] The air-dried basis equivalent sample quantity (m) of the second coal fed into the furnace.zs,2 :m zs,2 =m2×(100-M) s,2 ) / 100

[0074] =1000×(100-2.22) / 100

[0075] = 977.80(t)

[0076] (7) Step 7: Calculate the mass fraction w of the two 3mm subsamples when merging the composite sample. i :

[0077] The mass fraction w1 of the first 3mm sample of coal fed into the furnace in the comprehensive sample:

[0078]

[0079] The mass fraction w2 of the second 3mm coal sample added to the furnace in the comprehensive sample:

[0080]

[0081] The calculation results show that 66.93:33.07 = 2.02:1, which is close to the ratio of 2000:1000 = 2:1 for the amount of raw coal fed into the furnace.

[0082] Example 2: Calculate the proportion of each sample in the monthly carbon emission verification comprehensive sample of 3mm coal used daily in a power plant for inspection.

[0083] (1) Step 1: The particle size of each sample used for merging the monthly carbon emission verification air-dried basis composite sample is 3 mm;

[0084] (2) Second step: There are two days' worth of 3mm coal samples for inspection in the current month, that is, there are two sub-samples, and the corresponding raw coal consumption m for the two sub-samples is... i The corresponding received moisture content M of the coal fed into the furnace ar,i， The air-dried basis moisture content (M) of the two samples at the time of sampling ad,i The weights m of the two samples at that time s,i See the table below;

[0085]

[0086] (3) Third step: On the day of merging the composite samples, place each sample in an air-dried state at room temperature according to the GB / T474 standard method, and record the weight of the two samples when they reach the air-dried state. See the table below;

[0087]

[0088] (4) Step 4: Calculate the moisture content of the two samples on the calibration air-dried basis on the day of merging the composite sample.

[0089] Moisture content of the first sample on a calibration air-dried basis:

[0090]

[0091] Moisture content of the second sample on a calibration air-dried basis:

[0092]

[0093] (5) Step 5: Calculate the surface moisture M of the raw coal entering the furnace corresponding to the two samples. s.i ,

[0094] The surface moisture content (M) of the first batch of raw coal fed into the furnace s.1 : The surface moisture content M of the second batch of raw coal fed into the furnace s.2 : (6) Step 6: Calculate the air-dried basis equivalent sample quantity (m) of the raw coal entering the furnace corresponding to the two samples. zs,i :

[0095] The first batch of coal fed into the furnace, calculated on an air-dried basis, in m³. zs,1 :m zs,1 =m1×(100-M) s,1 ) / 100

[0096] =2000×(100-1.05) / 100

[0097] =1979.00(t)

[0098] The air-dried basis equivalent sample quantity (m) of the second coal fed into the furnace. zs,2 :m zs,2 =m2×(100-M) s,2 ) / 100

[0099] =1000×(100-20.50) / 100

[0100] =795.00(t)

[0101] (7) Step 7: Calculate the mass fraction w of the two 3mm subsamples when merging the composite sample. i :

[0102] The mass fraction w1 of the first 3mm sample of coal fed into the furnace in the comprehensive sample:

[0103]

[0104] The mass fraction w2 of the second 3mm coal sample added to the furnace in the comprehensive sample:

[0105]

[0106] The calculation results show that 71.34:28.66 = 2.49:1, which is significantly different from the ratio of 2000:1000 = 2:1 for the raw coal input into the furnace.

[0107] Comparative Example 1: The carbon emissions of the sample to be reviewed were calculated using the proportion of raw coal quantity.

[0108] The actual carbon emissions are calculated as follows:

[0109] Carbon content C of received sample 1 ar，1 =50%, total water M ar，1 =6%, air-dried basis moisture M ad，1 =5.50%, air-dried basis carbon content C ad，1 =50.27%, coal sample size 2000 tons (t);

[0110] The received basis carbon content of sample 2 is C. ar，2 =60%, total water M ar，2 =12%, air-dried basis moisture M ad，2 =10.80%, air-dried basis carbon content C ad，2 =60.82%, coal sample size 1000 tons (t); actual emissions are calculated as follows:

[0111] E 燃烧，实际 =2000×0.50×0.99×44 / 12+1000×0.60×0.99×44 / 12=5808(tCO2)

[0112] The carbon emissions were calculated using the raw coal quantity ratio for the sample reduction ratio as follows:

[0113] Total water content M in sample 1 ar，1 =6%, air-dried basis C ad，1 =50.27%, total water content M of sample 2 ar，2 =12%, air-dried basis carbon content C ad，2 =74.80%. The weighted average M of the total water content of the two samples. ar，加权 =13.48%, if the combined ratio of the two 3mm samples is 2:1 by mass, the weighted average moisture content M on an air-dried basis is... ad，加权 = (2×5.50+1×10.8) / 3=7.27(%), then the air-dried basis carbon content C of the combined sample is...ad，合并 = (2 × 50.27 + 1 × 74.80) / 3 = 58.45 (%), the converted carbon content of the received basis of the combined sample is C. ar，合并 =58.45×(100-13.48) / (100-7.27)=54.54(%).

[0114] Based on this calculation, the carbon emissions are:

[0115] E 燃烧，核算 =3000×0.5454×0.99×44 / 12=5939.41(tCO2)

[0116] Therefore, if the reduction ratio of the 3mm sample is based on the proportion of raw coal, the carbon emissions calculated at 5939.41 tons of CO2 when the actual coal consumption is 3000 tons differ from the actual emissions of 5808 tons by 131.41 tons. Taking two 600MW units as an example, with an annual coal consumption of approximately 2 million tons, the carbon emissions calculated based on this would differ from the actual emissions by approximately 87,600 tons.

[0117] Comparative Example 2: The carbon emissions of the sample to be examined were calculated using the method of this invention.

[0118] The actual carbon emissions are calculated as follows:

[0119] Carbon content C of received sample 1 ar，1 =50%, total water M ar，1 =6%, air-dried basis moisture M ad，1 =5.50%, air-dried basis carbon content C ad，1 =50.27%, coal sample size 2000 tons (t);

[0120] The received basis carbon content of sample 2 is C. ar，2 =60%, total water M ar，2 =28.45%, air-dried basis moisture M ad，2 =10.80%, air-dried basis carbon content C ad，2 =74.80%, coal sample size 1000 tons (t); actual emissions are calculated as follows:

[0121] E 燃烧，实际 =2000×0.50×0.99×44 / 12+1000×0.60×0.99×44 / 12=5808(tCO2)

[0122] The carbon emissions calculated using the method of this invention, based on the reduced sample ratio, are as follows:

[0123] According to the method of the present invention: the total water content of sample 1 is M ar，1 =6%, converted to air-dried basis moisture content The carbon content of the air-dried basis Total water content M in sample 2 ar，2 =28.45%, converted to air-dried basis moisture content Air-dried carbon content The weighted average of total moisture content from two samples, M ar，加权 =13.48%. If the combined ratio of the two 3mm samples is calculated according to this invention as a mass ratio of 2.49:1, the weighted average moisture content M on an air-dried basis is... ad，加权 = (2.49 × 5.00 + 1 × 10.0) / 3.49 = 6.43 (%), then the air-dried basis carbon content C of the combined sample is... ad，合并 = (2.49 × 50.53 + 1 × 75.47) / 3.49 = 57.68 (%), the converted carbon content of the received basis of the combined sample is C. ar，合并 =57.68×(100-13.48) / (100-6.43)=53.33(%).

[0124] Based on this calculation, the carbon emissions are:

[0125] E 燃烧，核算 =3000×0.5333×0.99×44 / 12=5807.64(tCO2)

[0126] Therefore, if the 3mm sample is combined with the composite sample according to the reduction ratio determined by the method of this invention, the calculated elemental carbon content is 53.33%, and the calculated carbon dioxide emission is 5807.64 tons. Since the calculation process retains two decimal places, if it is rounded to the nearest whole number, the result is 5808 tons, which is consistent with the actual emission of 5808 tons of carbon dioxide.

[0127] Example 3: Calculate the proportion of each sample in the monthly carbon emission verification comprehensive sample of 3mm coal used daily in a power plant for inspection.

[0128] Step 1: The particle size of each sample used for merging the air-dried basis composite samples for the monthly carbon emission verification is 3 mm;

[0129] Step 2: Two days' worth of 3mm coal samples were collected for inspection during the month, resulting in two separate samples. The corresponding raw coal consumption (m) for each sample was determined. i The corresponding received moisture content M of the coal fed into the furnace ar,i， The air-dried basis moisture content (M) of the two samples at the time of sampling ad,i The weights m of the two samples at that time s,i See the table below;

[0130]

[0131] Step 3: On the day of merging the composite samples, place each subsample in an air-dried environment at room temperature according to the GB / T474 standard method until it reaches an air-dried state, and record the weight of the two subsamples when they reach the air-dried state. See the table below;

[0132]

[0133] Step 4: Calculate the moisture content of the two individual samples on the calibration air-dried basis on the day of merging the composite sample.

[0134] Moisture content of the first sample on a calibration air-dried basis:

[0135]

[0136] Moisture content of the second sample on a calibration air-dried basis:

[0137]

[0138] Step 5: Calculate the surface moisture content M of the raw coal entering the furnace corresponding to the two samples. s.i ,

[0139] The surface moisture content (M) of the first batch of raw coal fed into the furnace s.1 :

[0140] The surface moisture content M of the second batch of raw coal fed into the furnace s.2 :

[0141] Step 6: Calculate the air-dried basis equivalent sample quantity (m) of the raw coal entering the furnace corresponding to the two subsamples. zs,i :

[0142] The first batch of coal fed into the furnace, calculated on an air-dried basis, in m³. zs,1 :m zs,1 =m1×(100-M) s,1 ) / 100

[0143] =2000×(100-1.05) / 100

[0144] =1979.00(t)

[0145] The air-dried basis equivalent sample quantity (m) of the second coal fed into the furnace. zs,2 :m zs,2 =m2×(100-M) s,2 ) / 100

[0146] =1000×(100-23.88) / 100

[0147] =761.20(t)

[0148] Step 7: Calculate the mass fraction w of the two 3mm subsamples when merging the composite sample. i :

[0149] The mass fraction w1 of the first 3mm sample of coal fed into the furnace in the comprehensive sample:

[0150]

[0151] The mass fraction w2 of the second 3mm coal sample added to the furnace in the comprehensive sample:

[0152]

[0153] The calculation results show that 72.22:27.78 = 2.60:1, which is significantly different from the ratio of 2000:1000 = 2:1 for the amount of raw coal fed into the furnace.

[0154] Comparative Example 3: Before preparing the comprehensive sample, the sample was not weighed to determine whether there was a change in moisture content, i.e., the impact of air-dried basis moisture content on the calculation of carbon emissions.

[0155] The actual carbon emissions are calculated as follows:

[0156] Carbon content C of received sample 1 ar，1 =50%, total water M ar，1 =6%, air-dried basis moisture M ad，1 =5.50%, air-dried basis carbon content C ad，1 =50.27%, coal sample size 2000 tons (t);

[0157] The received basis carbon content of sample 2 is C. ar，2 =60%, total water M ar，2 =28.45%, air-dried basis moisture M ad，2 =10.80%, air-dried basis carbon content C ad，2 =74.80%, coal sample size 1000 tons (t); actual emissions are calculated as follows:

[0158] E 燃烧，实际 =2000×0.50×0.99×44 / 12+1000×0.60×0.99×44 / 12=5808(tCO2)

[0159] Before preparing the comprehensive sample, the sample was not weighed. When calculating the reduction ratio of the reserve sample, the moisture content of sample 1 on an air-dried basis was M. ad，1 =5.50%, moisture content M on air-dried basis for two samples ad，2=10.80%, then the calculated carbon emissions are as follows:

[0160] The surface moisture content (M) of the first batch of raw coal fed into the furnace s.1 :

[0161] The surface moisture content M of the second batch of raw coal fed into the furnace s.2 :

[0162] Calculate the air-dried basis equivalent sample quantity (m) of the raw coal entering the furnace corresponding to the two subsamples. zs,i :

[0163] The first batch of coal fed into the furnace, calculated on an air-dried basis, in m³. zs,1 :m zs,1 =m1×(100-M) s,1 ) / 100

[0164] =2000×(100-0.53) / 100

[0165] =1989.40(t)

[0166] The air-dried basis equivalent sample quantity (m) of the second coal fed into the furnace. zs,2 :m zs,2 =m2×(100-M) s,2 ) / 100

[0167] =1000×(100-19.79) / 100

[0168] =802.09(t)

[0169] When calculating the mass fraction w of the two 3mm subsamples in the combined composite sample, i :

[0170] The mass fraction w1 of the first 3mm sample of coal fed into the furnace in the comprehensive sample:

[0171]

[0172] The mass fraction w2 of the second 3mm coal sample added to the furnace in the comprehensive sample:

[0173]

[0174] The determined merger ratio is: 71.27:28.73 = 2.48:1.

[0175] When preparing the total sample by reducing the sample size, both samples had already reached an air-dried state. At this point, the total water content of sample 1 was M. ar，1 =6%, air-dried basis moisture The carbon content of the air-dried basis Total water content M in sample 2 ar，2 =28.45%, air-dried basis moisture M ad，2 =6.00%, air-dried carbon content The weighted average of total moisture content from two samples, M ar，加权 =13.48%. The combined ratio of the two 3mm samples for retrieval was 2.48:1 by mass, and the weighted average of the moisture content on an air-dried basis was M. ad，加权 = (2.48 × 5.00 + 1 × 6.00) / 3.48 = 5.29 (%), then the air-dried basis carbon content C of the combined sample is... ad，合并 = (2.48 × 50.53 + 1 × 78.83) / 3.48 = 58.66 (%), the converted carbon content of the received basis of the combined sample is C. ar，合并 =58.66×(100-13.48) / (100-5.29)=53.59(%).

[0176] Based on this calculation, the carbon emissions are:

[0177] E 燃烧，核算 =3000×0.5359×0.99×44 / 12=5835.96(tCO2)

[0178] This demonstrates that: before preparing the composite sample, the samples were not weighed, and the original air-dried basis moisture content was used to calculate the reduction ratio of the reference sample. However, during the preparation of the composite sample, the air-dried basis moisture content of each sample changed, even reaching an air-dried state. If the original air-dried basis moisture content was still used to calculate the reduction ratio of the reference sample, the calculated carbon emissions of 5835.96 tons of CO2 with an actual coal consumption of 3000 tons differed from the actual emissions of 5808 tons of CO2 by 27.96 tons. Taking two 600MW units as an example, with an annual coal consumption of approximately 2 million tons, the calculated carbon emissions differed from the actual emissions by approximately 18640 tons.

[0179] The method for determining the comprehensive sample merging ratio for calculating the elemental carbon content of coal in this invention has strong practical applicability, a simple calculation process, and accurate results, and has high practical application value, providing a basis for accurately calculating the elemental carbon content of coal.

[0180] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0181] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a comprehensive sample for calculating the elemental carbon content of coal, characterized in that, Includes the following steps: The particle size, corresponding parameters of the coal fed into the furnace, and weight of each sample under air-dried conditions are obtained and merged for determining the elemental carbon content of the coal. The parameter information includes the raw coal consumption m corresponding to each sample. i The corresponding received moisture content M of the coal fed into the furnace ar,i Air-dried basis moisture content M of each sample ad,i and the original weight m of each sample s,i ; Based on the parameter information of the coal fed into the furnace corresponding to each sample and the weight of each sample under air-dried conditions, the calibrated air-dried basis moisture content of each sample is calculated when merging the composite sample. The calculation formula is: In the formula, The weight of each sample under air-dried conditions, m s,i The original weight of each sample; Calculate the surface moisture of the raw coal fed into the furnace corresponding to each sample based on the calibration air-dried basis moisture content. Based on the surface moisture content of the raw coal entering the furnace corresponding to each sub-sample, calculate the air-dried basis equivalent sample quantity of the raw coal entering the furnace corresponding to each sub-sample. Based on the air-dried basis of the raw coal entering the furnace corresponding to each sub-sample, calculate the mass fraction of each sub-sample when merging the comprehensive sample. Based on the mass fraction of each sample when merging the composite sample, the samples are combined to obtain the composite sample.

2. The method for preparing a comprehensive sample for calculating the elemental carbon content of coal according to claim 1, characterized in that, The particle size of each sample is 3 mm or 0.2 mm.

3. The method for preparing a comprehensive sample for calculating the elemental carbon content of coal according to claim 1, characterized in that, The weight of each sample under air-dried conditions is the weight of each sample when it is placed in air at room temperature to reach an air-dried state.

4. The method for preparing a comprehensive sample for calculating the elemental carbon content of coal according to claim 1, characterized in that, The air-drying state refers to the air-drying state achieved by placing each sample in an air-room environment according to the GB / T474 standard method.

5. The method for preparing a comprehensive sample for calculating the elemental carbon content of coal according to claim 1, characterized in that, The surface moisture content M of the raw coal fed into the furnace for each sample s.i Calculated using the following formula: M s.i —Surface moisture content of the i-th raw coal sample entering the furnace, in % . M ar,i —Moisture content of the i-th raw coal sample received, in % (%) —Moisture content of each sample on a calibration air-dried basis when combining composite samples, in % . i — the number of samples.

6. The method for preparing a comprehensive sample for calculating the elemental carbon content of coal according to claim 1, characterized in that, Air-dried basis equivalent sample quantity of raw coal entering the furnace for each sample Calculated using the following formula: In the formula, m i m represents the raw coal consumption for each sample entering the furnace. s,i The original weight of each sample.

7. The method for preparing a comprehensive sample for calculating the elemental carbon content of coal according to claim 1, characterized in that, Mass fraction of each sample when combining composite samples Calculated using the following formula: In the formula, The air-dried basis of the raw coal entering the furnace is converted into the sample quantity for each subsample.

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