Method for measuring calorific value of coal water slurry

Abstract

The invention provides a method for measuring the calorific value of coal water slurry, which comprises the following steps: S1, sampling the coal water slurry to obtain a sample greater than or equal to 0.5 L; s2, adding a combustion improver into the sample to form a mixture; s3, measuring the calorific value Q1 of the mixture by using a calorimeter; and S4, calculating the actual calorific value of the coal in the coal water slurry based on the calorific value Q1. By applying the method provided by the technical scheme of the invention, direct calorimetric is carried out on the superfine coal water slurry, so that the sampling reliability of a fluid sample is improved; the dilemma that ignition failure or incomplete combustion is easy to occur when the GB / T213-2008 method is adopted to carry out direct calorimetry on the coal water slurry, especially the superfine coal water slurry, is avoided; the calorimetric operation process is simplified, and the method has remarkable technical advantages and has important significance in promoting engineering application of a clean utilization technology of medium-and-low-rank coal water slurry and superfine coal water slurry.

Description

Technical Field

[0001] The invention relates to the technical field of water-coal slurry combustion, and in particular to a method for measuring the calorific value of water-coal slurry. Background Art

[0002] As one of the key strategies for the efficient and environmentally friendly utilization of China's coal resources, water-coal slurry technology plays a core role in the coal clean technology system. The calorific value of water-coal slurry is not only the cornerstone of measuring its quality, but also a key indicator that determines the efficiency of converting thermal energy into mechanical energy in industrial applications such as coal chemical industry and water-coal slurry power generation. However, with the continuous maturity of coal type optimization and blending technology, the mixed use of high-quality coal and low-quality fuels such as high-ash coal, coal gangue and coal slime is becoming increasingly common. The water-coal slurry prepared is then pushed to the market by a pricing mechanism based on calorific value and supplied to coal chemical industry and power generation companies. In this process, the industry gradually discovered that there is a significant deviation between the calorific value measured by the drying method currently used in the industry and the thermal power performance of water-coal slurry under actual operating conditions. This phenomenon has triggered controversy over the accuracy of the calorific value of water-coal slurry and the resulting quality.

[0003] Especially for coal-water slurries prepared from low-quality coal, their inherent high ash content, low calorific value and poor combustion efficiency frequently encounter the challenge of ignition failure when measuring calorific value using the drying method, which seriously restricts the reliability and applicability of the measurement. At the same time, with the iteration of technology, ultrafine coal-water slurries have regained favor in the fields of coal chemical industry and alternative petroleum products due to their excellent combustion performance. The particle size of this type of coal-water slurry can be as low as several microns or even less than 1 micron. When measuring its calorific value based on the drying method, it is difficult to accurately capture the true calorific value of the ultrafine coal powder, resulting in a disconnect between the measurement results and the actual application performance.

[0004] The method of wrapping the sample with lens paper mentioned in the drying method is intended to reduce the direct contact between the sample and the air and prevent water evaporation from affecting the measurement. However, in actual operation, lens paper may cause sample loss and introduce foreign pollutants, and its own uniformity problem has not been properly solved. While the operation is cumbersome, it increases the complexity and uncertainty of the measurement. In addition, as a complex suspension system formed by the mixture of coal powder and water, the heterogeneity of the internal structure of water-coal slurry imposes strict requirements on the sampling method. The diversity of coal and the inability to achieve completely uniform particle size in large-scale production of water-coal slurry make the inconsistency of coal concentration the main source of error in calorific value measurement, and its impact far exceeds the errors caused by technical factors in the measurement process.

[0005] However, none of the existing methods can directly and accurately measure the calorific value of water-coal slurry, especially for the measurement of the calorific value of ultra-fine water-coal slurry and low-quality coal water-coal slurry. This not only limits the accurate evaluation of the quality of water-coal slurry, but also affects the accurate measurement of its efficiency and economic value in industrial applications. Therefore, there is still a need to develop a method that can effectively cope with the complexity of water-coal slurry and achieve direct and reliable calorific value measurement. Summary of the invention

[0006] The main purpose of the present invention is to provide a method for measuring the calorific value of water-coal slurry to solve the problem that the methods in the prior art cannot directly and accurately measure the calorific value of water-coal slurry, especially the calorific value of ultrafine water-coal slurry and low-quality coal water-coal slurry.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a method for measuring the calorific value of water-coal slurry is provided, comprising the following steps: S1, emulsifying and homogenizing the water-coal slurry and sampling it to obtain a sample greater than or equal to 0.5L; S2, adding a combustion aid to the sample to form a mixture; S3, using a calorimeter to measure the calorific value Q1 of the mixture; S4, calculating the actual calorific value of coal in the water-coal slurry based on the calorific value Q1.

[0008] Furthermore, in the above method, step S1 further includes: S1-1 sampling the water-coal slurry to obtain a sample greater than or equal to 0.5 L, preferably using a single-slot or multi-slot sampler for multi-point vertical sampling; and S1-2, homogenizing the sample greater than or equal to 0.25 L, preferably using an emulsifier to emulsify the sample to form a paste without free water.

[0009] Furthermore, in the above method, the amount of the combustion aid to be added is determined according to the following steps: S2-1, measuring the calorific value of the combustion aid; S2-2, determining the concentration α of the coal powder in the water-coal slurry; S2-3, according to the formula Q 预估 =(M×α / 100)×Q 煤粉 Calculate the estimated calorific value of the water-coal slurry, where M is the weight of the water-coal slurry, and M is in the range of 1.5g to 2.3g; and S2-4, add a combustion aid according to the calorific value of the combustion aid being 30% to 70% of the estimated calorific value.

[0010] Furthermore, in the above method, step S3 further includes: S3-1, setting an asbestos wool layer at the bottom of the crucible of the calorimeter; S3-2, setting an asbestos bracket, a platinum mesh or a palladium mesh on the asbestos wool layer; S3-3, placing the mixture on the asbestos bracket, the platinum mesh or the palladium mesh; and S3-4, using a calorimeter to measure the calorific value Q1 of the mixture.

[0011] Furthermore, in the above method, the single-slot or multi-slot sampler comprises a strongly hydrophobic material.

[0012] Furthermore, in the above method, the emulsifier is an ultrasonic emulsifier, a mechanical stirring emulsifier or a mechanical ball mill, and step S1-2 includes placing a sample greater than or equal to 0.25 L in the emulsifier and homogenizing and emulsifying in a closed environment for 10 to 30 minutes.

[0013] Furthermore, in the above method, the combustion improver includes benzoic acid, benzoic acid derivatives or a combination thereof.

[0014] Furthermore, in the above method, the calorimeter is a constant temperature calorimeter, an adiabatic calorimeter, a thermal conductivity calorimeter, a universal automatic calorimeter, a differential scanning calorimeter or an oxygen bomb calorimeter.

[0015] Further, in the above method, step S3 includes measuring the calorific value Q1 of the mixture using an oxygen bomb calorimeter.

[0016] Furthermore, in the above method, step S4 includes: calculating the heat capacity E of the calorimeter according to the following formula: ba :

[0017]

[0018] Among them, Q ba is the calorific value of combustion in a benzoic acid calibration calorimeter, ΔT ba is the temperature rise of the calorimetric system in the benzoic acid calibration calorimeter, q f Release heat for the burning ignition wire,

[0019] q a To determine the heat of formation of the combustion aid during the process;

[0020] The calorific value Q2 of coal water slurry combustion is calculated according to the following formula:

[0021]

[0022] Among them, m c is the mass of water-coal slurry, q f is the heat released by the burning ignition wire, q a To determine the heat of formation of the combustion aid during the process,

[0023] ΔT c is the temperature change of the mixture during the measurement, C cp Cooling correction factor for constant temperature measurement of the barrel of the calorimeter;

[0024] Calculate the calorific value Q of water-coal slurry according to the following formula

[0025]

[0026] α is the concentration of coal powder in water-coal slurry.

[0027] Application of the technical solution of the present invention The method of the present invention performs direct calorimetry on ultrafine water-coal slurry, thereby improving the reliability of fluid sample sampling; avoiding the dilemma of ignition failure or incomplete combustion that is prone to occur when using the GB / T213-2008 method to perform direct calorimetry on water-coal slurry, especially ultrafine water-coal slurry; simplifying the calorimetric operation process, having significant technical advantages, and being of great significance for promoting the engineering application of clean utilization technology of medium and low-grade coal water-coal slurry and ultrafine water-coal slurry. DETAILED DESCRIPTION

[0028] It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments. The following embodiments are merely exemplary and do not constitute a limitation on the scope of protection of the present invention.

[0029] As described in the background technology, the methods in the prior art cannot directly and accurately measure the calorific value of water-coal slurry, especially for the measurement of the calorific value of ultra-fine water-coal slurry and low-quality coal water-coal slurry. In view of the problems in the prior art, a typical embodiment of the present invention provides a method for measuring the calorific value of water-coal slurry, comprising the following steps: S1, sampling the water-coal slurry to obtain a sample greater than or equal to 0.5L; S2, adding a combustion aid to the sample to form a mixture; S3, using a calorimeter to measure the calorific value Q1 of the mixture; S4, calculating the actual calorific value of the coal in the water-coal slurry based on the calorific value Q1.

[0030] In an embodiment of the present invention, multi-point vertical sampling of water-coal slurry is the key first step to ensure that the samples obtained can fully and accurately reflect the overall quality of the water-coal slurry. In order to further ensure the accuracy of the sampling process, the selection of the sampler is crucial. The single-slot or multi-slot sampler made of a highly hydrophobic material can not only effectively reduce the adhesion of water-coal slurry on the surface of the sampler and avoid sample loss, but also ensure the consistency of each sampling, thereby improving the reliability of the final calorific value measurement results. The provision that the total sampling volume is not less than 0.5L is also based on statistical principles to ensure that the sample size is large enough and reduce the statistical error caused by insufficient sampling, thereby making the measurement results closer to the true calorific value of the water-coal slurry.

[0031] The inventors have found that adding a certain amount of combustion improver to the sample after sampling can effectively help the sample to burn, thereby obtaining combustion heat more simply and effectively. The selection of the combustion improver should be based on its high calorific value, stability and compatibility with the water-coal slurry components. Benzoic acid or its derivatives are ideal choices for combustion improvers due to their stable chemical properties and high calorific value. Before use, the unit mass calorific value of the combustion improver should be accurately determined by existing standard measurement methods, such as GB / T213-2008, to ensure that its role in the measurement process is predictable and controllable. The combustion improver can be in powder form for easy uniform mixing with the water-coal slurry, or in tablet form for accurate weighing and operation.

[0032] Subsequently, a calorimeter is used to measure the calorific value of the mixture of water-coal slurry and combustion aid. There is a wide range of calorimeters to choose from, including constant temperature calorimeters, adiabatic calorimeters, thermal conductivity calorimeters, universal automatic calorimeters or differential scanning calorimeters (DSC), each of which has its own unique advantages and applicable scenarios. For example, a constant temperature calorimeter can provide a stable temperature environment to ensure accurate calculation of heat during the measurement process; while DSC can provide a more detailed heat change curve, which is helpful for analyzing the thermodynamic properties of the water-coal slurry combustion process. Regardless of which calorimeter is selected, the operating procedures of GB / T213-2008 should be strictly followed to obtain the bomb calorific value Q1 of the mixture.

[0033] Finally, based on the measured calorific value Q1 of the cartridge, the type and amount of the combustion aid, and the specific mass of the water-coal slurry sample, the actual calorific value of the water-coal slurry (coal in the water-coal slurry) can be accurately calculated using the calculation formula provided by the present invention. This calculation process comprehensively considers the influence of the combustion aid on the measurement results, as well as the actual contribution of the coal concentration in the water-coal slurry to the calorific value of the coal powder, thereby avoiding the deviation that may be caused by the indirect measurement method. In addition, by calculating the calorific value of the coal in the water-coal slurry, the actual calorific value of the ultrafine coal powder in the water-coal slurry can be further evaluated, which is of great significance for optimizing the water-coal slurry formula, improving combustion efficiency and reducing environmental pollution. This method is particularly suitable for the calorific value measurement of ultrafine water-coal slurry and low-grade coal water-coal slurry, and can more accurately reflect the actual working condition combustion calorific value of the water-coal slurry, providing strong technical support for the development of clean coal utilization technology.

[0034] The implementation of the method of the present invention can achieve direct and accurate measurement of the calorific value of water-coal slurry, solves the problems of uneven sampling of water-coal slurry, incomplete combustion, large deviation in calorific value measurement, etc. in traditional measurement methods, and provides a more scientific and reliable basis for the quality control, price setting and application of water-coal slurry in coal chemical industry and power generation fields.

[0035] In a further embodiment, the step S1 of sampling the water-coal slurry may further include: S1-1 sampling the water-coal slurry to obtain a sample greater than or equal to 0.5 L, preferably using a single-slot or multi-slot sampler for multi-point vertical sampling; and S1-2, homogenizing the sample greater than or equal to 0.25 L, preferably using an emulsifier to emulsify the sample to form a paste without free water.

[0036] In order to ensure that the collected water-coal slurry samples can fully represent the characteristics of the entire batch and avoid calorific value measurement errors caused by uneven sampling, this step preferably uses a single-slot or multi-slot sampler for multi-point vertical sampling. Single-slot or multi-slot samplers are usually made of highly hydrophobic materials, such as polytetrafluoroethylene (PTFE), polyethylene (PE), etc., to reduce the residue of water-coal slurry on the sampler, improve sampling efficiency and reduce sample loss. Multi-point vertical sampling refers to sampling from different depths and positions in a water-coal slurry storage or transportation container to ensure that the samples obtained can fully reflect the comprehensive characteristics of the water-coal slurry and avoid the influence of local characteristics and unevenness on the measurement results.

[0037] The water-coal slurry sample (greater than or equal to 0.25L) obtained in step S1-1 is transferred into an appropriate container, such as a plastic beaker, and stirred to preliminarily mix the sample. Subsequently, the sample is preferably further emulsified using an emulsifier to form a paste without free water. The emulsifier can be an ultrasonic emulsifier, a mechanical stirring emulsifier or a mechanical ball mill, which can effectively destroy the particle structure in the water-coal slurry, improve the mixing uniformity of coal powder and water, and eliminate free water, thereby ensuring the accuracy and repeatability of subsequent measurements. The emulsification process should be carried out in a closed container to prevent water evaporation or contamination by external impurities, which affects the measurement results. The emulsification time is generally 10 to 30 minutes, and the specific time depends on the type of emulsifier and the initial state of the water-coal slurry to ensure that the final sample has good homogeneity and stability.

[0038] Through the above steps S1-1 and S1-2, the problems of uneven particle size distribution, coal concentration and water content of the water-coal slurry can be effectively solved, providing a reliable basic sample for subsequent calorific value measurement.

[0039] When using a combustion aid, the following method is used to determine the amount of the combustion aid to be added according to the following steps: S2-1, measure the calorific value of the combustion aid; S2-2, determine the concentration α of the coal powder in the water-coal slurry; S2-3, according to the following formula

[0040] Q 预估 =(M×α / 100)×Q 煤粉

[0041] Calculate the estimated calorific value of the water-coal slurry, where M is the weight of the water-coal slurry, and M is in the range of 1.5g to 2.3g; and S2-4, add a combustion aid according to the calorific value of the combustion aid being 30% to 70% of the estimated calorific value.

[0042] First, measure the calorific value of the combustion aid. A high-precision calorimeter is required to measure the calorific value per unit mass of the combustion aid. This step usually adopts the method recommended in the national standard GB / T 213-2008, using benzoic acid or its derivatives as standard substances and measuring their calorific value by combustion. Benzoic acid or benzoic acid derivatives are ideal combustion aids because of their high calorific value, stable chemical properties, and are not prone to side reactions with components in water-coal slurry. Ensure that the measurement process is operated in accordance with the standard to obtain accurate and reliable combustion aid calorific value data.

[0043] Then, the concentration α of coal powder in the water-coal slurry is measured. The coal concentration of the water-coal slurry is a key factor affecting its calorific value. By analyzing the composition of the water-coal slurry, the mass percentage of coal powder in the water-coal slurry, i.e., the concentration α, can be determined. This step can be achieved by chemical analysis, density measurement and other methods to ensure the representativeness of the sampled water-coal slurry, thereby obtaining accurate coal powder concentration data.

[0044] Then, according to the formula Q 预估 =(M×α / 100)×Q 煤粉 Calculate the estimated calorific value of the water-coal slurry, where M is the weight of the water-coal slurry, M is in the range of 1.5g to 2.3g; based on the concentration of coal powder in the water-coal slurry α and the calorific value of the coal powder Q 煤粉 , the calorific value Q of water-coal slurry samples with different weights M (1.5g to 2.3g) can be estimated 预估 The calorific value of coal powder Q can be determined experimentally or obtained from a known coal calorific value database. This formula takes into account the actual mass ratio of coal powder in water-coal slurry and the calorific value of coal, providing a basis for the subsequent calculation of the amount of combustion aid to be added.

[0045] The combustion aid is added according to the calorific value of the combustion aid, which is 30% to 70% of the estimated calorific value. In order to ensure that the mixture can be fully burned in the calorimeter, the calorific value of the combustion aid should account for a certain proportion of the estimated calorific value. According to experimental experience, the proportion is selected to be 30% to 70%. The estimated calorific value Q obtained by calculation 预估 , the amount of combustion aid to be added can be determined. For example, if the estimated calorific value is Q 预估 The calorific value of the combustion aid is Q 助燃剂 , then the amount of combustion aid added can be calculated by the following formula:

[0046] Q 助燃剂 =30%~70% Q 预估

[0047] In some preferred embodiments of the present invention, step S3 of measuring the calorific value Q1 of the mixture by a calorimeter may further include: S3-1, setting an asbestos wool layer at the bottom of the crucible of the calorimeter; S3-2, setting an asbestos bracket, a platinum mesh or a palladium mesh on the asbestos wool layer; S3-3, placing the mixture on the asbestos bracket, the platinum mesh or the palladium mesh; and S3-4, using a calorimeter to measure the calorific value Q1 of the mixture.

[0048] A layer of high-temperature treated asbestos wool is laid on the bottom of the crucible of the calorimeter. The asbestos wool layer needs to be acid-washed in advance to remove impurities, and then heat-treated at a high temperature ranging from 1500℃ to 2000℃ to ensure that it will not change in mass or release absorbed heat during the combustion process, thereby avoiding interference with the calorific value measurement results. The role of the asbestos wool layer is to provide an inert, porous support structure, increase the contact area between the mixture and oxygen, and promote complete combustion.

[0049] Place an asbestos stand, platinum mesh or palladium mesh on the asbestos fleece layer as a support for the fluid sample. Asbestos stands, platinum mesh and palladium mesh have extremely low thermal conductivity and good chemical inertness, ensuring that they will not react with water-coal slurry or combustion aids during combustion. At the same time, the high porosity of these materials can effectively increase the contact area between water-coal slurry and oxygen, and improve combustion efficiency. The selection of the stand should take into account its minimal thermal effect on the calorimeter to ensure the accuracy of the measurement.

[0050] Use a micro single-slot or multi-slot sampler or a micro bucket sampler to accurately measure 1.5-2.5g of water-coal slurry sample and place it evenly on the asbestos support, platinum mesh or palladium mesh. Make sure the mixture is spread flat and in close contact with the support to facilitate uniform heat release. In addition, the distribution of the mixture should be as uniform as possible to avoid local over-dense or sparse, which affects the stability of combustion and the accuracy of measurement.

[0051] After placing the mixture of water-coal slurry and combustion-supporting agent on the support, use a calorimeter (such as a constant temperature calorimeter, adiabatic calorimeter, thermal conductivity calorimeter, universal automatic calorimeter or differential scanning calorimeter) to measure according to the operating procedures in the national standard GB / T213 2008. Before measuring, make sure that the sample is completely stable and the ignition wire (or other ignition device) is correctly installed. During the measurement, record the temperature change from the beginning to the end of combustion, as well as the thermal effect of the calorimeter. The calorimeter will automatically calculate and output the calorific value of the mixture of water-coal slurry and combustion-supporting agent. This data will be used for the subsequent calculation of the calorific value of the bomb of the water-coal slurry and the calorific value of the coal in the water-coal slurry.

[0052] Through these refined steps, it can be ensured that the mixture of water-coal slurry and combustion aid burns more completely and stably, thereby improving the accuracy and reliability of calorific value measurement and avoiding measurement errors caused by poor combustion conditions. It is especially suitable for the calorific value determination of water-coal slurry with high ash content, high water content and ultra-fine particle size.

[0053] The present invention adopts a single-slot or multi-slot sampler, and its design and manufacturing focus on the characteristics of water-coal slurry, especially its high water content and suspended state, so a strong hydrophobic material is used to ensure the accuracy of the sampling process and the integrity of the sample. The selection of a strong hydrophobic material is crucial to prevent the water-coal slurry from being retained, adsorbed or forming a water film on the surface of the sampler, thereby reducing sample loss and contamination, ensuring the representativeness of the sampling point, and improving the reliability of calorific value measurement.

[0054] The highly hydrophobic material of the sampler can be a polymer material such as polytetrafluoroethylene (PTFE), polyethylene (PE), and polypropylene (PP). These materials not only have good chemical stability and can resist the erosion of various components in the water-coal slurry, but also have low surface energy and are not easily wetted by water molecules, effectively preventing the adhesion of the water-coal slurry on the surface of the sampler. In addition, you can also choose a specially treated metal material, such as stainless steel that has been plated or surface modified to make its surface hydrophobic, but the metal sampler should be careful to avoid reacting with the components in the water-coal slurry to affect the measurement results.

[0055] In terms of design, the trough part of the sampler should have a smooth surface to reduce the residue of water-coal slurry. At the same time, the shape and size of the trough should match the rheology and particle size of the water-coal slurry to ensure the consistency and representativeness of the sampling. For multi-trough samplers, the spacing between the troughs and the arrangement of the troughs should also be carefully designed to ensure that the samples obtained from different depths and positions can be evenly mixed to reflect the overall calorific value characteristics of the water-coal slurry.

[0056] During use, the hydrophobic surface of the sampler must be kept clean to avoid interference from any foreign matter. Before sampling, compressed air or dry nitrogen can be used to purge the surface of the sampler to remove water droplets or coal powder residues that may affect sampling, ensuring that the sampler is in the best hydrophobic state.

[0057] Single-slot or multi-slot samplers made of highly hydrophobic materials can effectively solve many problems in water-coal slurry sampling, such as residual moisture, coal powder adsorption, poor sampling representativeness, etc., so that the sampled water-coal slurry samples are closer to their actual state, ensuring the accuracy of subsequent emulsification and homogenization, combustion aid dosage matching and calorific value determination steps, thereby improving the overall accuracy and reliability of water-coal slurry calorific value measurement.

[0058] The emulsifier used in the present invention is an ultrasonic emulsifier, a mechanical stirring emulsifier or a mechanical ball mill. Preferably, the emulsifier has an efficient homogenization ability and a good temperature control function to ensure that the physical and chemical properties of the water-coal slurry remain stable during the emulsification process. In step S1-2 described above, a water-coal slurry sample greater than or equal to 0.25L is placed in a closed container of an emulsifier, and homogenization and emulsification are performed in a closed environment. The emulsification time is preferably 10 minutes to 30 minutes to ensure that the coal powder particles in the water-coal slurry are completely combined with water to generate a paste sample without free water, while avoiding changes in sample properties caused by excessive emulsification time. The rotation speed or ultrasonic frequency during the emulsification process should be adjusted according to the sample characteristics and the desired emulsification effect to achieve the best emulsification effect. For example, the frequency of the ultrasonic emulsifier can be set between 20kHz and 40kHz, the rotation speed of the mechanical stirring emulsifier can be set between 500rpm and 5000rpm, and the rotation speed of the mechanical ball mill can be set between 30rpm and 300rpm. In addition, the emulsifier should have good sealing performance to prevent the evaporation of water or the mixing of external impurities during the emulsification process, thereby ensuring that the emulsified sample can accurately reflect the composition and characteristics of the original water-coal slurry.

[0059] During the emulsification process, the cooling system of the emulsifier should also be considered to avoid the heat generated during the emulsification process causing the temperature of the water-coal slurry to rise, thereby affecting the subsequent calorific value determination. The cooling system can be water-cooled, air-cooled or other effective cooling methods to ensure that the temperature during the emulsification process is controlled within an appropriate range, for example, the temperature is controlled between 20°C and 40°C to prevent the water in the water-coal slurry from evaporating too quickly, and to avoid too low a temperature that causes the fluidity of the coal powder to decrease, affecting the emulsification effect.

[0060] Through the above-mentioned emulsification process, the uniformity and stability of the water-coal slurry sample can be significantly improved, and the calorific value measurement error caused by sample unevenness can be reduced. At the same time, the emulsified paste sample is easier for subsequent sampling and combustion aid addition steps, thereby improving the accuracy and reliability of the entire calorific value determination process.

[0061] The combustion improver used in the present invention includes but is not limited to benzoic acid, benzoic acid derivatives or their combination, wherein the benzoic acid derivatives can be structural analogs such as phthalic acid, terephthalic acid, isophthalic acid, etc. The above compounds are used as combustion improvers because they have the following advantages: the calorific value of benzoic acid and its derivatives is high, and the properties are stable at normal temperature and pressure, and decomposition or oxidation reaction is not easy to occur, which ensures the accuracy of calorimetric measurement. Benzoic acid and its derivatives can provide stable heat energy output when burning, and the combustion products are mainly carbon dioxide and water, and side reactions will not occur with the water-coal slurry components, such as generating additional heat or causing incomplete combustion, thereby affecting the measurement results. Benzoic acid and its derivatives are easy to prepare into powder or tablet form, which is convenient for accurate weighing and storage. In calorimetric experiments, the tablet form can reduce the loss of samples and improve the repeatability and accuracy of experiments. These compounds produce fewer harmful substances during the combustion process. Compared with other combustion improvers, the use of benzoic acid and its derivatives is more conducive to the safe conduct of experiments, and also reduces the impact on the environment. According to the present invention, the amount of the combustion aid is calculated based on the fact that its calorific value accounts for 30% to 70% of the total calorific value of the mixed sample. The setting of this ratio ensures that the mixture of water-coal slurry and combustion aid can be effectively burned in the calorimeter, while avoiding the measurement error caused by excessive combustion aid. The use of benzoic acid and its derivatives is not only applicable to conventional water-coal slurry, but also effective for the calorific value measurement of ultrafine water-coal slurry and low-grade coal water-coal slurry, which is mainly due to their combustion characteristics and stability.

[0062] Therefore, choosing benzoic acid and its derivatives as combustion aids can effectively solve the problems of ignition failure, incomplete combustion and measurement errors that are prone to occur in the direct calorimetry process of water-coal slurry, and improve the reliability and accuracy of calorific value measurement.

[0063] As described above, the calorimeter used in the present invention can be a constant temperature calorimeter, an adiabatic calorimeter, a thermal conductivity calorimeter, an all-purpose automatic calorimeter, a differential scanning calorimeter (DSC) or an oxygen bomb calorimeter (Bomba Calorimeter). The constant temperature calorimeter keeps the ambient temperature constant during the measurement process, and calculates the calorific value of the sample by measuring the heat change during the combustion process. It is suitable for measuring samples with medium calorific value and high requirements for temperature change, and can effectively reduce the impact of external temperature fluctuations on the measurement results. The adiabatic calorimeter carries out combustion reaction in a completely adiabatic environment, and can accurately measure the calorific value of the sample without being affected by the external temperature. It is suitable for measuring samples with high calorific value and susceptible to interference from the external environment, and its measurement accuracy is usually higher than that of a constant temperature calorimeter. The thermal conductivity calorimeter calculates the calorific value of the sample by measuring the change in thermal conductivity during heat transfer. It is suitable for measuring samples with low calorific value or samples that need to be measured under a specific temperature gradient, and its measurement process is closer to actual combustion conditions. The all-purpose automatic calorimeter integrates multiple calorimetric technologies such as constant temperature, adiabatic, and oxygen bomb. It has automatic control, data processing, and error correction functions. It is suitable for measuring samples of various types and calorific value levels. It is simple to operate, has high measurement accuracy, and good repeatability. The differential scanning calorimeter calculates the calorific value of the sample by comparing the heat flow difference between the sample and the reference material during the heating or cooling process. It is suitable for measuring the thermal transition process of materials, such as melting, solidification, decomposition, etc., and is also suitable for measuring the calorific value of complex systems such as water-coal slurry. The oxygen bomb calorimeter is a closed calorimetric device. The sample is completely burned in a bomb filled with oxygen, and the calorific value of the sample is calculated by measuring the temperature change of the water bath before and after combustion. It is suitable for directly measuring the calorific value of solid fuels, liquid fuels, and gaseous fuels. It is the calorific value determination method for water-coal slurry recommended in the national standard GB / T213 2008.

[0064] The above calorimeters all have specific working principles and operating steps, and choosing a suitable calorimeter is crucial for accurately measuring the calorific value of water-coal slurry. In practical applications, the most suitable calorimeter should be selected for measurement according to the specific characteristics of the water-coal slurry, such as water content, ash content, type and particle size of coal, etc., as well as the accuracy requirements of the measurement. For example, for water-coal slurry with high water content, high ash content or ultra-fine water-coal slurry, an adiabatic calorimeter or a differential scanning calorimeter may be required to ensure complete combustion and the accuracy of the measurement results; while for conventional water-coal slurry, a constant temperature calorimeter or an oxygen bomb calorimeter may be sufficient to meet the measurement requirements. In addition, with the advancement of technology, the all-round automatic calorimeter has gradually become the preferred equipment for measuring the calorific value of water-coal slurry due to its convenient operation and high precision. Preferably, step S3 includes using an oxygen bomb calorimeter to measure the calorific value Q1 of a mixture of water-coal slurry and a combustion aid.

[0065] In a further preferred embodiment, step S4 includes calculating the actual calorific value of coal in the water-coal slurry according to the following formula:

[0066] Calculate the heat capacity E of the calorimeter ba :

[0067]

[0068] Among them, Q ba The calorific value of combustion in a benzoic acid calibration calorimeter,

[0069] ΔT ba The temperature rise of the calorimetric system is measured by the benzoic acid calibration calorimeter.

[0070] q f Release heat for the burning ignition wire,

[0071] q a To determine the heat of formation of the combustion aid during the process;

[0072] Calculate the calorific value Q2 of coal water slurry combustion:

[0073]

[0074] Among them, m c is the mass of coal water slurry,

[0075] q f The heat released by the burning ignition wire,

[0076] q a To determine the heat of formation of the combustion aid during the process,

[0077] ΔT c is the temperature change of the mixture during the measurement,

[0078] C cp Cooling correction factor for constant temperature measurement of the barrel of the calorimeter;

[0079] Calculate the calorific value Q of coal in water-coal slurry

[0080]

[0081] α is the mass percentage concentration of coal powder in water-coal slurry.

[0082] If the measured sample is coal powder, α=1 (ie: 100%).

[0083] Example

[0084] Example 1

[0085] The sample to be tested is made of the coal blended by the National Energy Group, with a coal concentration of 65.3% wt and d(0.5)=55.966 μm.

[0086] A single-slot polyethylene sampler was used to vertically sample at multiple points to extract about 600 ml of water-coal slurry, which was quickly transferred to a 1000 ml plastic beaker. A mechanical stirrer was used to evenly stir the 600 ml water-coal slurry, and an emulsifier was used to emulsify the sample: the speed of the emulsifier was 10000-11000 r / min, and the emulsification time was 5-6 minutes to prepare a paste sample without free water.

[0087] According to the method of national standard GB / T213 2008, benzoic acid is used as the standard substance (calorific value is 26458J / g), and the heat capacity E of the calorimeter (oxygen bomb calorimeter) is calibrated. ba ; It is planned to take about 2.0g of water-coal slurry sample. According to the measurement relationship that the calorific value of the combustion aid accounts for 60% of the calorific value of the water-coal slurry, weigh 1.3g of the combustion aid tablet. The mass of the combustion aid tablet weighed by a precision balance is 1.1320g.

[0088] A layer of high-temperature treated asbestos wool was laid on the bottom of the crucible of the calorimeter. A multi-layer asbestos woven mesh frame heat-treated at 1800℃ was placed on the asbestos wool as a sample holder; about 2.0g of water-coal slurry was measured with a single-slot sampler and transferred to the sample holder of the crucible, and weighed with a precision balance to determine that the mass of the water-coal slurry was 2.1352g; according to the calorimeter operation process in the national standard GB / T213 2008, the calorific value of the sample to be tested was Q1 using a fully automatic calorimeter (5E-AC / PL automatic calorimeter of Changsha Kaiyuan Instrument Co., Ltd.), and the measurement was repeated five times. The measurement results are as follows:

[0089] The first time: 59.3693MJ, the second time: 59.3716MJ, the third time: 59.3875MJ, the fourth time: 59.2895MJ, and the fifth time: 59.2391MJ. The average value calculated after five measurements is:

[0090] Q1=59.3314MJ

[0091] The difference between the maximum and minimum heat values ​​of the cartridge measured five times is 106.4 J / g (coal), which meets the basic repeatability requirements specified in GB / T2132008.

[0092] The water-coal slurry Q2 and the calorific value of the coal in the water-coal slurry Q are calculated based on Q1. The system automatically outputs the calorimetric results according to equations (1), (2), and (3):

[0093] Q2=13.75MJ / kg

[0094] Q=21.06MJ / kg

[0095] Comparative Example 1

[0096] The same sample to be tested as in Example 1 was used, emulsified and homogenized, and the same amount of combustion aid as in Example 1 was added, and then the calorific value was measured using the national standard method GB / T213 2008. The measured calorific value Q0 of the blended coal was 24.15 MJ / kg.

[0097] The difference between the calorific value Q obtained in Example 1 and the Q0 obtained in Comparative Example 1 is

[0098] 21.06MJ / kg-24.15MJ / kg-=-3.09MJ / kg

[0099] The difference comes from the strong hydrophilic micro-nano pore structure of large coal powder particles (d(0.5) = 55.966 μm) in the water-coal slurry. The water has a large negative pressure and is difficult to volatilize, causing the calorific value of the coal in the water-coal slurry to be lower than the calorific value of the same amount of dry coal.

[0100] Comparative Example 2

[0101] The same amount of sample to be tested as in Example 1 was used, and the emulsified homogenized sample was taken without adding a combustion aid. The calorific value was directly measured according to the national standard method GB / T213 2008. The calorific value Q0 of the obtained coal-blended bomb was measured. ′ It is: 23.51MJ / kg.

[0102] The calorific value Q0 obtained in Comparative Example 2 ′ The difference compared with Q0 obtained in Comparative Example 1 is

[0103] 23.51MJ / kg-24.15MJ / kg=0.64MJ / kg

[0104] The difference comes from the fact that no combustion aid is added, and residual carbon particles are still mixed in the ash after combustion, resulting in incomplete combustion of the low-rank coal contained in the water-coal slurry and a low calorific value.

[0105] The calorific value Q obtained in Example 1 is different from the calorific value Q obtained in Comparative Example 2. ′ The difference is

[0106] 21.06MJ / kg-23.53MJ / kg-=-2.047MJ / kg

[0107] The difference comes from the strong hydrophilic micro-nano concave pore structure of large-particle coal powder in water-coal slurry, which has a large negative pressure on water and is difficult to volatilize, causing the calorific value of coal in water-coal slurry to be lower than that of the same amount of dry coal.

[0108] Comparative Example 3

[0109] The same amount of sample to be tested as in Example 1 was used without emulsification and homogenization. The upper slurry was taken and the same amount of combustion aid as in Example 1 was added. The calorific value was measured according to the national standard method GB / T213 2008. The calorific value Q0 of the obtained coal-blended cartridge was measured. ′ It is: 20.37MJ / kg.

[0110] The calorific value Q0 obtained in Comparative Example 3 ′ The difference compared with Q0 obtained in Comparative Example 1 is

[0111] 20.37MJ / kg-24.15MJ / kg=-3.78MJ / kg

[0112] The difference comes from the fact that the sampling was not emulsified and homogenized, and the coal concentration of the upper slurry obtained was significantly lower than the average coal concentration of the slurry. However, the calorific value was still calculated based on the average coal concentration of the sample to be tested, and the calculated calorific value of the sample to be tested was too low.

[0113] The calorific value Q obtained in Example 1 is different from the calorific value Q obtained in Comparative Example 3. ′ The difference is

[0114] 21.06MJ / kg-20.37MJ / kg-=-0.69MJ / kg

[0115] Compared with Comparative Example 1, the reduced difference comes from the fact that the sampling was not emulsified and homogenized, and the coal concentration of the upper slurry obtained was significantly lower than the average coal concentration of the slurry. The calorific value was still calculated based on the average coal concentration of the sample to be tested, and the calculated calorific value of the sample to be tested was too low.

[0116] Comparative Example 4

[0117] The same amount of sample to be tested as in Example 1 was used without emulsification and homogenization. The bottom slurry was taken and the same amount of combustion aid as in Example 1 was added. The calorific value was measured using the national standard method GB / T213 2008. The calorific value Q0 of the obtained coal blend was measured. ′ It is: 25.33MJ / kg.

[0118] The calorific value Q0 obtained in Comparative Example 4 ′ The difference compared with Q0 obtained in Comparative Example 1 is

[0119] 25.33MJ / kg-24.15MJ / kg=+1.18MJ / kg

[0120] The difference comes from the fact that the sampling was not emulsified and homogenized, and the coal concentration of the bottom slurry obtained was significantly higher than the average coal concentration of the slurry. However, the calorific value was still calculated based on the average coal concentration of the sample to be tested, and the calculated calorific value of the sample to be tested was too high.

[0121] The calorific value Q obtained in Example 1 is different from the calorific value Q obtained in Comparative Example 4. ′ The difference is

[0122] 21.06MJ / kg-25.33MJ / kg-=-4.27MJ / kg

[0123] Compared with Comparative Example 1, the increased difference comes from the fact that the sampling was not emulsified and homogenized, and the coal concentration of the obtained bottom slurry was significantly higher than the average coal concentration of the slurry. The calorific value was still calculated based on the average coal concentration of the sample to be tested, and the calculated calorific value of the sample to be tested was too high.

[0124] Example 2

[0125] The measurement steps of implementation case 2 are carried out in the same manner as in embodiment 1, except that:

[0126] The sample to be tested is made of coal blended by the Guoneng Junneng Group as raw material, and 0.15%wt of hydrophobic additive multi-walled carbon nanotubes are added to regulate the coal-water surface tension; the coal concentration α of the water-coal slurry is 62.2%wt, and the particle size d(0.5)=2.62μm; the weighed water-coal slurry is 1.8151g, and the combustion aid benzoic acid is 0.5007g, and its calorific value is about 40% of the calorific value of the water-coal slurry.

[0127] The calorific value Q1 of the mixture of water-coal slurry and combustion aid was measured by a fully automatic calorimeter (5E-AC / PL automatic calorimeter of Changsha Kaiyuan Instrument Co., Ltd.). The average value calculated after 5 measurements was:

[0128] Q1=44.3918MJ

[0129] The difference between the maximum and minimum heat values ​​of the cartridge measured five times is 148.2 J / g (coal), which meets the basic repeatability requirements specified in GB / T2132008.

[0130] The water-coal slurry Q2 and the calorific value of the coal in the water-coal slurry Q are calculated based on Q1. The system automatically outputs the calorimetric results according to equations (1), (2), and (3):

[0131] Q2=13.75MJ / kg

[0132] Q=27.32MJ / kg

[0133] Comparative Example 5

[0134] The same sample to be tested as in Example 2 was used, emulsified and homogenized, and the same amount of combustion aid as in Example 2 was added, and the calorific value was measured using the national standard method GB / T213 2008. The measured calorific value Q0 of the coal blend was 24.15 MJ / kg.

[0135] The difference between the calorific value Q obtained in Example 2 and the Q0 obtained in Comparative Example 5 is

[0136] 27.32MJ / kg-24.15MJ / kg=3.17MJ / kg

[0137] The difference comes from the micro-nano effect of coal powder particles and the regulation of coal-water interfacial tension in the micro-nano pores of coal powder by additives, which increases the curvature radius of water and reduces the negative pressure of water in the micro-nano pores.

[0138] Example 3

[0139] The measurement steps of implementation case 3 are carried out in the same manner as in embodiment 1, except that:

[0140] The sample to be tested is made of coal blended by the Guoneng Junneng Group as raw material, and 0.15%wt hydrophobic additive multi-walled carbon nanotubes are added to regulate the coal-water surface tension; the coal concentration α of the water-coal slurry is 49.27%wt, and the particle size d(0.5)=5.12μm; the weighed water-coal slurry is 1.8273g, and the combustion aid benzoic acid is 0.6567g, and its calorific value is about 70% of the calorific value of the water-coal slurry.

[0141] The calorific value Q1 of the mixture of water-coal slurry and combustion aid was measured by a fully automatic calorimeter (5E-AC / PL automatic calorimeter of Changsha Kaiyuan Instrument Co., Ltd.). The average value calculated after 5 measurements was:

[0142] Q1=42.2962MJ

[0143] The difference between the maximum and minimum heat values ​​of the cartridge measured five times is 137.4 J / g (coal), which meets the basic repeatability requirements specified in GB / T2132008.

[0144] The water-coal slurry Q2 and the calorific value of the coal in the water-coal slurry Q are calculated based on Q1. The system automatically outputs the calorimetric results according to equations (1), (2), and (3):

[0145] Q2=13.58MJ / kg

[0146] Q=27.57MJ / kg

[0147] It can be seen that under the condition of the same coal type and similar particle size, the calorific value measurement result of the water-coal slurry in the above Example 3 is well consistent with the result of Example 2.

[0148] Comparative Example 6

[0149] The same sample to be tested as in Example 3 was used, emulsified and homogenized, and the same amount of combustion aid as in Example 3 was added, and the calorific value was measured using the national standard method GB / T213 2008. The measured calorific value Q0 of the blended coal was 24.16 MJ / kg.

[0150] The difference between the calorific value Q obtained in Example 3 and the Q0 obtained in Comparative Example 6 is

[0151] 27.57MJ / kg-24.16MJ / kg=+3.41MJ / kg

[0152] The difference comes from the micro-nano effect of coal powder particles, which increases the calorific value; by regulating the coal-water interfacial tension in the micro-nano pores of coal powder through additives, the curvature radius of water is increased, the negative pressure of water in the micro-nano pores is reduced, and the heat consumed by the evaporation of water on the concave surface is reduced.

[0153] Example 4

[0154] The measurement steps of Example 4 are carried out in the same manner as in Example 1, except that:

[0155] The sample to be tested is made of coal blended by the Guoneng Junneng Group as raw material, and 0.15%wt of hydrophobic additive multi-walled carbon nanotubes are added to regulate the coal-water surface tension; the coal concentration α of the water-coal slurry is 62.2%wt, and the particle size d(0.5)=2.62μm; the weighed water-coal slurry is 2.2518g, and the combustion aid benzoic acid is 0.4636g, and its calorific value is about 30% of the calorific value of the water-coal slurry.

[0156] The calorific value Q1 of the mixture of water-coal slurry and combustion aid was measured by a fully automatic calorimeter (5E-AC / PL automatic calorimeter of Changsha Kaiyuan Instrument Co., Ltd.). The average value calculated after 5 measurements was:

[0157] Q1=50.6029MJ

[0158] The difference between the maximum and minimum heat values ​​of the cartridge measured five times is 122.4 J / g (coal), which meets the basic repeatability requirements specified in GB / T2132008.

[0159] The water-coal slurry Q2 and the calorific value of the coal in the water-coal slurry Q are calculated based on Q1. The system automatically outputs the calorimetric results according to equations (1), (2), and (3):

[0160] Q2=17.02MJ / kg

[0161] Q=27.36MJ / kg

[0162] The calorific value measurement results of the above-mentioned coal-water slurry are in good consistency with those of Example 2 and Example 3.

[0163] Comparative Example 7

[0164] The same sample to be tested as in Example 4 was used, emulsified and homogenized, and the same amount of combustion aid as in Example 4 was added, and then the calorific value was measured using the national standard method GB / T213 2008. The measured calorific value Q0 of the blended coal was 24.18 MJ / kg.

[0165] The difference between the calorific value Q obtained in Example 4 and the Q0 obtained in Comparative Example 7 is

[0166] 27.36MJ / kg-24.18MJ / kg=+3.18MJ / kg

[0167] The difference comes from the micro-nano effect of coal powder particles, which increases the calorific value; by regulating the coal-water interfacial tension in the micro-nano pores of coal powder through additives, the curvature radius of water is increased, the negative pressure of water in the micro-nano pores is reduced, and the heat consumed by the evaporation of water on the concave surface is reduced.

[0168] It can be seen from the above embodiments that the method for measuring the calorific value of water-coal slurry of the present invention can effectively solve the problems existing in the traditional measurement method: through large-capacity sampling and homogenization emulsification treatment, the calorific value measurement error caused by uneven sampling is significantly reduced, making the measurement result of the calorific value of water-coal slurry more accurate and in line with the repeatability requirements specified in GB / T213 2008. The use of a combustion-aiding agent with stable performance and high calorific value, such as benzoic acid or its derivatives, can ensure that when measuring the calorific value of water-coal slurry, even low-rank coal or ultra-fine water-coal slurry can be ignited smoothly, avoiding measurement failures caused by ignition failure or incomplete combustion. By directly measuring the calorific value of water-coal slurry instead of drying it first and then measuring it, the method of the present invention can better reflect the combustion calorific value of water-coal slurry during actual use, which is of great value for evaluating the actual thermal energy conversion efficiency of water-coal slurry. Directly measuring the calorific value of water-coal slurry reduces the sample pretreatment steps and shortens the overall measurement time. At the same time, since the energy consumption during the drying process is avoided, the measurement cost is also reduced and the efficiency is improved. The method of the present invention is not only applicable to conventional water-coal slurry, but also to ultra-fine water-coal slurry and low-grade coal water-coal slurry, and can also obtain reliable and effective calorific value measurement results, thus expanding the application scope of water-coal slurry calorific value measurement. The entire measurement process is standardized and streamlined, and equipment such as a strong hydrophobic sampler, an emulsifier, and a calorimeter are used to simplify the operation steps, reduce the difficulty of operation, and improve the measurement efficiency and reliability of the results. The measurement method of the present invention reduces the energy consumption during the drying process, reduces the impact of the measurement process on the environment, and meets the requirements of green and low-carbon development.

[0169] In summary, the method of the present invention not only improves the accuracy and reliability of measurement, but also simplifies the operation process and reduces the measurement cost. It has significant technical and economic advantages and is of great significance for promoting the development of clean coal utilization technology.

[0170] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for measuring the calorific value of coal water slurry, characterized in that: The following steps are involved: S1, emulsify and homogenize the water-coal slurry and take samples to obtain a sample of 0.5 L or more; S2, adding a combustion aid to the sample to form a mixture; S3, measuring the calorific value Q1 of the mixture using a calorimeter; S4, calculating the actual calorific value of the coal in the water-coal slurry based on the calorific value Q1.

2. The method according to claim 1, characterized in that Step S1 further comprises: S1-1 sampling the water-coal slurry to obtain a sample of 0.5 L or more, preferably using a single-slot or multi-slot sampler for multi-point vertical sampling; and S1-2, homogenizing a sample of 0.25 L or more, preferably using an emulsifier to emulsify the sample to form a paste without free water.

3. The method according to claim 1, characterized in that The amount of the combustion aid to be added is determined by the following steps: S2-1, measuring the calorific value of the combustion aid; S2-2, determining the concentration α of the coal powder in the water-coal slurry; S2-3, according to formula Q 预估 =(M×α / 100)×Q 煤粉 Calculating an estimated calorific value of the coal water slurry, wherein M is the weight of the coal water slurry, M is in the range of 1.5 g to 2.3 g, and the estimated calorific value of the coal water slurry is the estimated calorific value of the coal powder in the coal water slurry; and S2-4, adding the combustion aid according to the calorific value of the combustion aid being 30% to 70% of the estimated calorific value.

4. The method according to claim 1, characterized in that: Step S3 further comprises: S3-1, providing an asbestos wool layer at the bottom of the crucible of the calorimeter; S3-2, placing an asbestos stent, a platinum mesh or a palladium mesh on the asbestos wool layer; S3-3, placing the mixture on the asbestos support, platinum mesh or palladium mesh; and S3-4, using the calorimeter to measure the calorific value Q1 of the mixture.

5. The method according to claim 2, characterized in that: The single-slot or multi-slot sampler comprises a strongly hydrophobic material.

6. The method according to claim 2, characterized in that The emulsifier is an ultrasonic emulsifier, a mechanical stirring emulsifier or a mechanical ball mill, and step S1-2 includes placing a sample of 0.25 L or more in the emulsifier and homogenizing and emulsifying in a closed environment for 10 to 30 minutes.

7. The method according to claim 1, characterized in that The combustion improver includes benzoic acid, benzoic acid derivatives or a combination thereof.

8. The method according to claim 1, characterized in that: The calorimeter is a constant temperature calorimeter, an adiabatic calorimeter, a thermal conductivity calorimeter, an all-purpose automatic calorimeter, a differential scanning calorimeter or an oxygen bomb calorimeter.

9. The method according to claim 1, characterized in that: Step S3 includes measuring the calorific value Q1 of the mixture using an oxygen bomb calorimeter.

10. The method according to claim 1, characterized in that Step S4 includes: Calculate the heat capacity E of the calorimeter according to the following formula ba : Among them, Q ba The calorific value of combustion in a benzoic acid calibration calorimeter, ΔT ba The temperature rise of the calorimetric system is measured by the benzoic acid calibration calorimeter. q f Release heat for the burning ignition wire, q a To determine the heat of formation of the combustion aid during the process; The calorific value Q2 of coal water slurry combustion is calculated according to the following formula: Among them, m c is the mass of coal water slurry, q f The heat released by the burning ignition wire, q a To determine the heat of formation of the combustion aid during the process, ΔT c is the temperature change of the mixture during the measurement, C cp Cooling correction factor for constant temperature measurement of the barrel of the calorimeter; Calculate the calorific value Q of coal in water-coal slurry according to the following formula: α is the concentration of coal powder in the water-coal slurry.

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