Coal calorific value calculation method and system

Abstract

The application relates to the field of coal, in particular to a coal heat calculation method and system. The method comprises the following steps: based on a known coal sample database, optimizing and pre-storing model parameter sets of organic matter molecular structure corresponding to different coal types; when the heat value of a to-be-detected coal sample is calculated, the coal type, element content and ash content data of the coal sample are obtained; the corresponding pre-stored parameter set is called according to the coal type; high-sulfur coal or low-sulfur coal is divided according to the amount-of-substance relationship between sulfur elements and Fe / Ti, and the endothermic quantity Q 矿物质 of mineral matter is calculated according to the distribution of mineral elements to a preset chemical reaction library ; the number of core structure units and alkyl side chains in organic matter is determined through the amount-of-substance conservation equation of organic carbon and hydrogen, and the heat value Q 有机质 of organic matter is calculated ; the comprehensive heat value is obtained based on the formula Q v =Q 有机质 -Q 矿物质 ; the defects of poor universality and failure to consider the influence of sulfur and mineral matter in the traditional method are solved, the error is small, and the heat value calculation requirement of an industrial coal sample is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal, in particular to a coal calorific value calculation method and system. BACKGROUND

[0002] As an important energy resource, the calorific value of coal is a core index for measuring the energy value and economic properties of coal, which directly affects coal quality classification, combustion efficiency, cost accounting and environmental protection indicators. Currently, the methods for determining the calorific value of coal mainly include experimental measurement, empirical formula and statistical analysis. However, these methods have obvious limitations: experimental measurement has high accuracy, but requires professional equipment and a long test period; using multivariate linear regression and artificial neural network to study the correlation between industrial analysis data such as ash content and volatile matter and calorific value, the empirical formula obtained lacks universality and is only applicable to specific regions, coal mines or coal types.

[0003] Therefore, it is of great significance to develop a coal calorific value calculation method that can comprehensively consider the influence of mineral chemical reactions, organic molecular structure and sulfur form, in order to improve the efficiency and accuracy of industrial coal quality analysis. SUMMARY

[0004] The present application provides a coal calorific value calculation method and system, which can comprehensively consider the organic molecular structure of coal, the composition of mineral elements and their chemical reaction types, and has high accuracy and universality.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] A coal calorific value calculation method, comprising the following steps:

[0007] Data acquisition step: acquiring the basic data of the coal sample to be measured, including coal type, carbon (C), hydrogen (H), sulfur (S) element mass content, and ash content and mass percentage of oxides in ash;

[0008] Parameter calling step: according to the coal type of the coal sample to be measured, calling the pre-stored corresponding organic molecular structure model parameter set, the parameter set including core structure unit parameters (RN, a, b), average number of carbon atoms L1 of alkyl side chain and its corresponding combustion heat value G5, and average number of bridging bonds L2;

[0009] Heat absorption calculation step: according to the amount-of-substance relationship of sulfur (S), iron (Fe) and titanium (Ti) elements in coal, high-sulfur coal or low-sulfur coal is divided; the mineral elements are assigned to a pre-set chemical reaction library, and the heat of each reaction and the amount of substance are used to calculate the heat of each mineral, and the total heat absorption Q of the minerals is summed up. 矿物质

[0010] ​Heat calculation step: using the called organic matter molecular structure model parameter set, through the amount of substance conservation equation of organic carbon and organic hydrogen, the number of core structure units x and the number of alkyl side chains y are determined, and based on the combustion heat value of the core structure unit and the combustion heat value G5 of the alkyl side chain, the heat value Q of the organic matter is obtained 有机质 ;

[0011] The comprehensive heat calculation step is based on the formula: Q v =Q 有机质 -Q 矿物质 , the comprehensive heat Q v is obtained.

[0012] Further, the pre-stored organic matter molecular structure model parameter set is called, and the establishment of the parameter set includes:

[0013] Sample database establishment step: obtaining the basic data of a plurality of groups of dry basis coal samples with known heat;

[0014] Parameter optimization step: traversing the preset value combination of core structure unit parameters (RN, a, b), average number of carbon atoms L1 of alkyl side chain, and average number of bridging bonds L2; for each parameter combination, calculate the heat calculation value of each coal sample in the sample database; taking the absolute error, root mean square error (RMSE) and complex determination coefficient (R 2 ) between the calculated value and the measured value as the evaluation index, and screening out the optimal parameter combination;

[0015] Parameter storage step: storing the optimal parameter combination and the corresponding coal type to form the parameter set.

[0016] Further, the coal type includes anthracite, bituminous coal and lignite; the mass content of carbon (C), hydrogen (H) and sulfur (S) elements is represented by B1, B2 and D1 respectively, and the mass content of ash is represented by A0; the oxides in the ash include silicon dioxide, aluminum oxide, iron oxide, calcium oxide, magnesium oxide, sodium oxide, potassium oxide, phosphorus pentoxide, titanium dioxide and sulfur trioxide, and the mass percentage of the oxides in the ash is represented by A1-A 10 .

[0017] Further, the high-sulfur coal or low-sulfur coal is divided according to the amount of substance relationship of sulfur (S), iron (Fe) and titanium (Ti) in coal; specifically including:

[0018] The Fe and Ti elements in the coal preferentially form the compound FeTiO3, and the remaining Fe and S form the compound FeS2. Comparing the amount of substance of Fe and S at this time, if the amount of substance of S is higher than that of Fe: (n Fe -n FeTiO3 )=<0.5n S, the rest of S is assigned to organic S;

[0019] If S is lower than the amount of substance of Fe: (n Fe -n FeTiO3 )>0.5n S , the rest of Fe forms compound FeCO3.

[0020] Further, the reactions in the chemical reaction library include:

[0021] Kaolinite Al2Si2O5(OH)4 is decomposed into SiO2, Al2O3 and H2O,

[0022] Illite K 0.8 Al2(Si,Al)4O 10 (OH)2 is decomposed into K2O, Al2O3, SiO2 and H2O,

[0023] FeS2 is oxidized into Fe2O3 and SO2,

[0024] CaCO3 is decomposed into CaO and CO2,

[0025] MgCO3 is decomposed into MgO and CO2,

[0026] FeTiO3 is oxidized into Fe2O3 and TiO2.

[0027] Further, the core unit structure is composed of RN benzene rings, including (a-(y / x+L2)) -CH (aromatic) functional groups, (b+(y / x+L2)) -C- (aromatic) functional groups, (a-(y / x+L2)) H atoms; the combustion heat value of the core structure unit is calculated according to the combustion heat value of its functional groups as follows:

[0028] Δ c H m =(-544.59)kJ / mol×(a-(y / x+L2))+(-393.51)kJ / mol×(b+(y / x+L2)

[0029] =-[(544.59a+393.51b)-151.08(y / x+L2)]kJ / mol,

[0030] Wherein: RN represents the number of benzene rings in the core structure unit, a represents the number of -CH (aromatic) functional groups in each core structure unit, b represents the number of -C- (aromatic) functional groups in each core structure unit; y is the total number of alkyl side chains, x is the total number of core structure units, y / x represents the average number of alkyl side chains connected to each core structure unit; L2 represents the average number of bridging bonds in each core structure unit; the number of benzene rings RN takes an integer value of 1 to 12.

[0031] Further, each alkyl side chain consists of L1 C atoms and (2L1+1) H atoms; each core structure unit contains (a+b) C atoms, (a-(y / x+L2)) H atoms; the amount of substance conservation equation of organic carbon and hydrogen elements includes:

[0032] The amount of substance B of organic carbon in coal 11 =n C -B 12 =(0.08333B1-B 12 ) mol = ((a+b)x+L1y) mol,

[0033] The amount of substance n of organic hydrogen in coal H =B2 mol = ((a-(y / x+L2))x+(2L1+1)y) mol,

[0034] Wherein: a represents the number of -CH (aromatic) functional groups in each core structure unit, b represents the number of -C- (aromatic) functional groups in each core structure unit; y is the total number of alkyl side chains, x is the total number of core structure units; L1 represents the average number of carbon atoms in each core structure unit; L2 represents the average number of bridging bonds in each core structure unit; L1 takes a value of 0.5-1, 1.5-2, 2.5-3, 3.5-4, 4.5-5, 5.5-6, 6.5-7, and the value after the decimal point is accurate to one place.

[0035] The application also provides a coal calorific value calculation system, comprising:

[0036] A data acquisition module is configured to acquire basic data of a coal sample to be measured, including coal type, mass content of carbon (C), hydrogen (H), and sulfur (S) elements, mass content of ash, and mass percentage of oxides in ash;

[0037] A parameter calling module is configured to call a pre-stored corresponding organic matter molecular structure model parameter set according to the coal type of the coal sample to be measured, wherein the parameter set includes core structure unit parameters (RN, a, and b), average number of carbon atoms L1 of alkyl side chains, corresponding combustion heat value G5, and average number of bridging bonds L2.

[0038] The heat absorption calculation module is used to classify coal into high-sulfur or low-sulfur coal based on the molar relationships of sulfur (S), iron (Fe), and titanium (Ti) elements in the coal. It allocates mineral elements to a pre-defined chemical reaction library, calculates the heat of each mineral based on the heat of combustion and molar amounts of each reaction, and sums the results to obtain the total heat absorption Q of the minerals. 矿物质 ;

[0039] The calorific value calculation module uses the parameter set of the called organic matter molecular structure model to determine the number of core structural units x and the number of alkyl side chains y through the conservation of substance equations for organic carbon and organic hydrogen. Based on the calorific value of the core structural units and the calorific value G5 of the alkyl side chains, the calorific value of the organic matter Q is obtained by summing them. 有机质 ;

[0040] The integrated calorific value module is used based on the formula: Q v =Q 有机质 -Q 矿物质 Calculate the total calorific value Q. v .

[0041] Furthermore, the coal calorific value calculation system of this application includes a parameter storage module for storing the parameter set of organic matter molecular structure model corresponding to different coal types;

[0042] It also includes a module for constructing a parameter set for an organic matter molecular structure model. The construction of the parameter set includes: [The parameter set construction includes:] an organic matter molecular structure model parameter set, wherein the parameter set construction includes:

[0043] Sample database establishment: Obtain basic data from multiple sets of dried coal samples with known calorific value;

[0044] Parameter optimization: Iterate through the preset combinations of core structural unit parameters (RN, a, b), average number of carbon atoms in alkyl side chains L1, and average number of bridging bonds L2; ​​for each parameter combination, calculate the calorific value of each coal sample in the sample database; and use the absolute error, root mean square error (RMSE), and multiple determination coefficient (R²) between the calculated and measured values. 2 Using these as evaluation indicators, the optimal parameter combination is selected.

[0045] Parameter storage: The optimal parameter combination is associated with the corresponding coal type and stored to form the parameter set.

[0046] Furthermore, the core unit structure consists of RN benzene rings, including (a-(y / x+L2)) -CH (aromatic) functional groups, (b+(y / x+L2)) -C- (aromatic) functional groups, and (a-(y / x+L2)) H atoms;

[0047] Wherein: RN represents the number of benzene rings in the core structure unit, a represents the number of -CH (aromatic) functional groups in each core structure unit, b represents the number of -C- (aromatic) functional groups in each core structure unit; y is the total number of alkyl side chains, x is the total number of core structure units, y / x represents the average number of alkyl side chains connected to each core structure unit; L2 represents the average number of bridging bonds in each core structure unit; the number of benzene rings RN takes an integer from 1 to 12.

[0048] Beneficial effects:

[0049] High accuracy: The method comprehensively considers the molecular structure model of organic matter, mineral element composition and chemical reaction type of coal, not only considers the heat of organic matter of coal, but also analyzes the heat absorption of minerals in the combustion process and the influence of sulfur element, which can more accurately calculate the heat of coal, the absolute error is small, and meets the industrial coal sample heat calculation requirements.

[0050] Strong universality: Through the matching rules of different core structure units and average carbon atom number of alkyl side chains, the chemical composition and structural characteristics of different coal types can be adapted, and the calculation of coal samples with carbon content of more than 40% can be basically applied.

[0051] The coal heat calculation system provided by the application has systematic design, and through the cooperative work of the data acquisition module, the heat absorption calculation module, the heat calculation module and the comprehensive heat calculation module, the automatic calculation of the coal heat is realized, and the calculation efficiency and accuracy are improved. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0053] Fig. 1 The flowchart of the coal heat calculation method of the application is shown in the figure.

[0054] Fig. 2 The core structure unit with benzene ring linear arrangement and the core structure unit with benzene ring closest arrangement when RN is 3 are shown in the figure. DETAILED DESCRIPTION

[0055] In order for the person skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor fall within the scope of protection of the present application.

[0056] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly disposed on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0057] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0058] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of", "several" is two or more, unless otherwise explicitly specified.

[0059] It should be understood that the structures, proportions, sizes and the like shown in the drawings of the present application are only used to cooperate with the content disclosed in the description, to enable those skilled in the art to understand and read, and do not have technical significance, and any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0060] The embodiments of the present application are written in a progressive manner.

[0061] Referring to Figs. 1-2 A coal calorific value calculation method, comprising the following steps:

[0062] Data acquisition step: acquire the basic data of the coal sample to be tested, including coal type, carbon (C), hydrogen (H), sulfur (S) element mass content, and ash mass content and mass percentage of oxides in ash;

[0063] Parameter calling step: according to the coal type of the coal sample to be tested, a pre-stored corresponding organic matter molecular structure model parameter set is called, the parameter set including core structure unit parameters (RN, a, b), average carbon atom number L1 of alkyl side chain and corresponding combustion heat value G5, and average number L2 of bridging bonds;

[0064] Heat absorption calculation step: according to the amount-of-substance relationship of sulfur (S), iron (Fe) and titanium (Ti) elements in coal, high-sulfur coal or low-sulfur coal is divided; the mineral elements are distributed to a pre-set chemical reaction library, the heat of each mineral is calculated according to the combustion heat and amount of substance of each reaction, and the total heat absorption Q of the mineral is summed up 矿物质 ;

[0065] Heat generation calculation step: the called organic matter molecular structure model parameter set is used to determine the number x of core structure units and the number y of alkyl side chains through the amount-of-substance conservation equation of organic carbon and organic hydrogen, and the heat generation Q of organic matter is obtained by adding the combustion heat value of the core structure unit and the combustion heat value G5 of the alkyl side chain 有机质 ;

[0066] Comprehensive heat generation calculation step, based on the formula: Q v =Q 有机质 -Q 矿物质 , the comprehensive heat generation Q v is obtained.

[0067] The method has high calculation accuracy and strong universality; the organic matter molecular structure model of coal, the composition of mineral elements and the chemical reaction type are comprehensively considered, not only the heat generation of organic matter of coal is considered, but also the heat absorption of mineral matter in the combustion process and the influence of sulfur element are analyzed in detail, so that the heat generation of coal can be more accurately calculated, the absolute error is small, and the industrial coal sample heat calculation requirement is met; in addition, through different matching rules of the average carbon atom number of the core structure unit and the alkyl side chain, the chemical composition and structural characteristics of different coal types can be adapted, and the method is basically applicable to the calculation of coal samples with carbon content of more than 40%.

[0068] Further, a pre-stored organic matter molecular structure model parameter set is called, and the establishment of the parameter set includes:

[0069] Sample database establishment step: acquire the basic data of a plurality of dry base coal samples with known heat generation;

[0070] Parameter optimization step: traverse preset core structure unit parameter (RN, a, b), average carbon atom number L1 of alkyl side chain, average number L2 of bridging bonds; for each parameter combination, calculate the calorific value of each coal sample in the sample database; with the absolute error, root mean square error (RMSE) and complex determination coefficient (R 2 ) between the calculated value and the measured value as evaluation index, the optimal parameter combination is screened out;

[0071] Parameter storage step: store the optimal parameter combination and the corresponding coal type to form the parameter set.

[0072] Further, the coal type includes anthracite, bituminous coal and lignite; the mass content of carbon (C), hydrogen (H) and sulfur (S) elements is represented by B1, B2 and D1 respectively, and the mass content of ash is represented by A0; the oxides in ash include silicon dioxide, aluminum oxide, iron oxide, calcium oxide, magnesium oxide, sodium oxide, potassium oxide, phosphorus pentoxide, titanium dioxide and sulfur trioxide, and the mass percentage of the oxides in ash is represented by A1-A 10 .

[0073] Further, the high-sulfur coal or low-sulfur coal is divided according to the amount-of-substance relationship of sulfur (S), iron (Fe) and titanium (Ti) elements in coal; specifically including:

[0074] The Fe and Ti elements in coal preferentially form the compound FeTiO3, and the remaining Fe and S form the compound FeS2. Comparing the amount-of-substance of Fe and S at this time, if the amount-of-substance of S is higher than that of Fe: (n Fe -n FeTiO3 )<0.5n S , it is divided into high-sulfur coal, and the remaining S is distributed in organic S;

[0075] If the amount-of-substance of S is lower than that of Fe: (n Fe -n FeTiO3 )>0.5n S , it is divided into low-sulfur coal, and the remaining Fe forms the compound FeCO3.

[0076] Further, the reactions in the chemical reaction library include:

[0077] kaolinite Al2Si2O5(OH)4 is decomposed into SiO2, Al2O3 and H2O,

[0078] illite K 0.8 Al2(Si,Al)4O 10 (OH)2 is decomposed into K2O, Al2O3, SiO2 and H2O,

[0079] FeS2 is oxidized into Fe2O3 and SO2,

[0080] CaCO3 decomposes into CaO and CO2,

[0081] MgCO3 decomposes into MgO and CO2,

[0082] FeTiO3 oxidizes into Fe2O3 and TiO2.

[0083] Further, the core structure unit consists of RN number of benzene rings, including (a-(y / x+L2)) -CH (aromatic) functional groups, (b+(y / x+L2)) -C- (aromatic) functional groups, (a-(y / x+L2)) H atoms; the combustion heat value of the core structure unit is calculated according to the combustion heat value of its functional groups as follows:

[0084] Δ c H m =(-544.59)kJ / mol×(a-(y / x+L2))+(-393.51)kJ / mol×(b+(y / x+L2)

[0085] =-[(544.59a+393.51b)-151.08(y / x+L2)]kJ / mol,

[0086] Wherein: RN represents the number of benzene rings forming the core structure unit, a represents the number of -CH (aromatic) functional groups in each core structure unit, b represents the number of -C- (aromatic) functional groups in each core structure unit; y is the total number of alkyl side chains, x is the total number of core structure units, y / x represents the average number of alkyl side chains connected to each core structure unit; L2 represents the average number of bridging bonds in each core structure unit.

[0087] Further, the mass conservation equation of organic carbon and organic hydrogen includes:

[0088] The mass of organic carbon in coal B 11 =n C -B 12 =(0.08333B1-B 12 ) mol = ((a+b)x+L1y) mol,

[0089] The mass of organic hydrogen in coal n H =B2 mol = ((a-(y / x+L2))x+(2L1+1)y) mol,

[0090] Wherein, a represents the number of -CH (aromatic) functional groups in each core structure unit, b represents the number of -C- (aromatic) functional groups in each core structure unit; y is the total number of alkyl side chains, x is the total number of core structure units; L1 is the average number of carbon atoms of alkyl side chain in each core structure unit; L2 represents the average number of bridging bonds in each core structure unit.

[0091] As a feasible way, the present application indirectly obtains the mass content of mineral elements in coal from the way of "oxide in ash", and calculates the coal calorific value, and the representation method of each mass content is shown in Table 1:

[0092]

[0093] The carbon element in coal contains organic carbon and inorganic carbon; the sulfur element contains organic sulfur and inorganic sulfur; the object of calculation is a dry basis coal sample, so the mass content of hydrogen element is equal to the mass content of organic hydrogen.

[0094] For the convenience of understanding the present embodiment, the calculation of the calorific value of 1g dry basis coal sample is taken as an example for description:

[0095] If the mass content of carbon in 1g coal is equal to 80%, then B1=0.80g; if the mass content of SiO2 in coal ash is equal to 50%, then A1=0.5; in the calculation process, other letters such as B2, D1, A1 are used similarly.

[0096] The amount of substance n of element C C =B1g÷12g / mol=0.08333B1mol=(B 11 +B 12 )mol;

[0097] The amount of substance n of element H H =B2g÷1g / mol=B2mol, the object of calculation is a dry basis coal sample, and the amount of substance of element hydrogen is equal to that of organic hydrogen;

[0098] The amount of substance n of element S S =D1g÷32g / mol=0.03125D1mol=(D3+D2)mol;

[0099] The mass m of ash A =1g×A0=A0g;

[0100] The amount of substance n of SO3 in coal ash SO3 =A0g×A 10 ÷80.06g / mol=0.01249A0A 10 mol, the amount of substance n of SO2 converted into SO3 SO2 =0.01249A0A10 mol;

[0101] The alkali metals Na and K will volatilize a part during the combustion of the coal sample at 815°C, so the amount of substance n Na = 0.01613A0A6x2x(1+30%) = 0.04194A0A6 mol;

[0102] The amount of substance n K = 0.01062A0A7x2x(1+30%) = 0.02762A0A7 mol;

[0103] Based on the law of conservation of elements, the content conversion between oxides and elements is shown in Table 2:

[0104] Table 2

[0105]

[0106] There are mainly five categories of mineral matter in coal: clay minerals (about 60%-80% of the total amount of mineral matter, mainly kaolinite Al2Si2O5(OH)4, illite K 0.8 Al2(Si,Al)4O 10 (OH)2, and sericite K{Al2[Si3AlO 10 ](OH)2}), sulfides (pyrite FeS2, marcasite FeS, and pyrrhotite Fe 1-x S, a small amount of sphalerite ZnS, galena PbS, and chalcopyrite CuFeS2 in most coal seams), phosphates (apatite Ca5F(PO4)3, Ca5OH(PO4)3, Ca5Cl(PO4)3), carbonates (mainly coexisting minerals are siderite FeCO3 and dolomite CaMg(CO3)2, and metamorphic stage mainly calcite CaCO3 and ankerite (Fe, Ca, Mg)CO3), and sulfates (alkali metal, alkaline earth metal, and iron sulfates and complex salts);

[0107] According to the composition of the mineral matter in coal, the types of chemical reactions that may occur during high-temperature combustion of the mineral matter are inferred, for example, kaolinite loses crystal water to convert into metakaolinite at 327°C, and decomposes into acicular r -Al2O3 and mullite (3Al2O3·2SiO2); the thermal decomposition of calcite (CaCO3, MgCO3) includes two independent reactions, calcium carbonate begins to decompose into calcium oxide and carbon dioxide at 650°C, and magnesium carbonate begins to decompose into magnesium oxide and carbon dioxide at 590°C.

[0108] The composition of the mineral matter is simplified in this application, for example, K 0.8 Al2(Si,Al)4O 10(OH)2represents the chemical composition of illite (in fact, illite represents a silicate mineral with a similar mica layer structure, and there is no accurate molecular formula). Meanwhile, the chemical reactions that occur during high-temperature combustion are also complex, and the chemical reactions of various minerals are mutually influenced and difficult to distinguish. The present application defines that the chemical reactions that occur during the combustion of various minerals are independent of each other, and the reaction products are common stable oxides, so that the types of chemical reactions in which each mineral participates and their combustion heat values are determined.

[0109] The chemical reactions of minerals in coal during combustion and the combustion heat values are shown in Table 3. Since kaolinite Al2Si2O5(OH)4 and illite K 0.8 Al2(Si,Al)4O 10 (OH)2is a mixture, only the range value of the combustion heat thereof is obtained; the chemical reaction library is shown in Table 3:

[0110] Table 3

[0111]

[0112] Table 3 shows that if each element is in a different compound, different chemical reactions will occur during combustion, and the combustion heat is different. In particular, the sulfur element in coal is a complex existence, including organic sulfur and inorganic sulfur. According to the different mass contents of S elements, the coal samples are divided into high-sulfur coal and low-sulfur coal.

[0113] In the present application, it is defined that the Fe and Ti elements in coal preferentially form the compound FeTiO3, and the remaining Fe and S form the compound FeS2. The amount of substance of Fe and S at this time is compared.

[0114] If the amount of substance of S is higher than that of Fe (high-sulfur coal), the remaining S is distributed to organic S, that is, (n Fe -n FeTiO3 )=<0.5n S , (0.01252A0A3-0.01252A0A9) mol=<0.01562D1 mol;

[0115] If the amount of substance of S is lower than that of Fe (low-sulfur coal), the remaining Fe forms the compound FeCO3; that is, (n Fe -n FeTiO3 )>0.5n S , (0.01252A0A3-0.01252A0A9) mol>0.01562D1 mol; specifically,

[0116] (i) high-sulfur coal, (n Fe -n FeTiO3 )=<0.5n S

[0117] Ti in coal is due to the compound FeTiO3, whose amount of substance = 0.01252A0A9 mol;

[0118] Fe in coal is due to the compounds FeTiO3and FeS2, whose amount of substance = (0.01252A0A3-0.01252A0A9) mol;

[0119] S in coal is due to the compounds FeS2and organic S,

[0120] whose amount of substance = (0.03125D1-0.02504A0A3+0.02504A0A9) mol;

[0121] Si in coal is due to the mixture Al2Si2O5(OH)4(kanemite), whose amount of substance = 0.01664A0A1 mol;

[0122] Al in coal is due to the mixture Al2Si2O5(OH)4(kanemite), whose amount of substance = 0.00981A0A2 mol;

[0123] P in coal is due to the compound Ca5(PO4)3F, whose amount of substance = 0.004697A0A8 mol;

[0124] Ca in coal is due to the compounds Ca5(PO4)3F and CaCO3,

[0125] whose amount of substance = (0.01783A0A4-0.02348A0A8) mol;

[0126] Mg in coal is due to the compound MgCO3, whose amount of substance = 0.02481A0A5 mol;

[0127] Na in coal is due to the compound Na2CO3, whose amount of substance = 0.02097A0A6 mol;

[0128] K in coal is due to the compound K2CO3, whose amount of substance = 0.01381A0A7 mol;

[0129] Amount of substance of SO3 in coal ash n SO3 = A0g x A 10 ÷ 80.06 g / mol = 0.01249A0A 10 mol, amount of substance of SO2 converted to SO3 n SO2 = 0.01249A0A 10 mol;

[0130] The inorganic carbon in coal is derived from CaCO3, MgCO3, Na2CO3 and K2CO3, the amount of substance of which is:

[0131] B 12 = (0.01783A0A4-0.02348A0A8) + 0.02481A0A5 + 0.02097A0A6 + 0.01381A0A7 mol;

[0132] According to the heat value of combustion of the chemical reactions of the minerals in Table 3, Table 4 shows the heat change generated by the chemical reactions of each compound:

[0133]

[0134]

[0135] From the above Table 4, the heat absorption of coal is equal to the heat change generated by the chemical reactions of the minerals and element S, the heat absorption of coal:

[0136] Q 矿物质 = 2.496A0A1 + 1.4715A0A2 - (10.4442A0A3 - 10.4442A0A9)

[0137] + (3.1826A0A4 - 4.1912A0A8) + 2.8928A0A5 + 6.7356A0A6 + 5.4688A0A7

[0138] + 5.2216A0A8 + 0.5321A0A9 - 1.2365A0A 10 - (9.25D1 - 7.4118A0A3 + 7.4118A0A9) kJ.

[0139] (ii) Low-sulfur coal, (n Fe -n FeTiO3 )> 0.5n S

[0140] The Ti in coal is due to the compound FeTiO3, the amount of substance of which is 0.01252A0A9 mol;

[0141] The S in coal is due to the compound FeS2, the amount of substance of which is 0.01562D1 mol;

[0142] The Fe in coal is due to the compounds FeTiO3, FeS2 and FeCO3,

[0143] The amount of substance of FeCO3 is (0.01252A0A3 - 0.01252A0A9 - 0.01562D1) mol;

[0144] Si in coal is due to the mixture Al2Si2O5(OH)4 (kaolinite), the amount of substance of SiO2 in clay = 0.01664A0A1 mol;

[0145] Al in coal is due to the mixture Al2Si2O5(OH)4 (kaolinite), the amount of substance of Al2O3 in clay = 0.00981A0A2 mol;

[0146] P in coal is due to the compound Ca5(PO4)3F, the amount of substance = 0.004697A0A8 mol;

[0147] Ca in coal is due to the compounds Ca5(PO4)3F and CaCO3,

[0148] the amount of substance of CaCO3 = (0.01783A0A4 - 0.02348A0A8) mol;

[0149] Mg in coal is due to the compound MgCO3, the amount of substance = 0.02481A0A5 mol;

[0150] Na in coal is due to the compound Na2CO3, the amount of substance = 0.02097A0A6 mol;

[0151] K in coal is due to the compound K2CO3, the amount of substance = 0.01381A0A7 mol;

[0152] Inorganic carbon in coal is derived from CaCO3, MgCO3, Na2CO3, K2CO3 and FeCO3, the amount of substance:

[0153] B 12 = (0.01783A0A4 - 0.02348A0A8) + 0.02481A0A5 + 0.02097A0A6 + 0.01381A0A7 + (0.01252A0A3 - 0.01252A0A9 - 0.01562D1) mol;

[0154] According to the heat value of combustion of the chemical reactions of minerals in Table 3, Table 5 shows the heat change generated by the chemical reactions of each compound:

[0155] Table 5

[0156]

[0157] From the above Table 5, the heat absorption of coal is equal to the heat change generated by the chemical reactions of minerals, the heat absorption of coal:

[0158] Q 矿物质= 2.496A0A1 + 1.4715A0A2 - 13.0302D1 + (3.1826A0A4 - 4.1912A0A8)

[0159] + 2.8928A0A5 + 6.7356A0A6 + 5.4688A0A7 + 5.2216A0A8 + 0.5321A0A9 - 1.2365A0A 10

[0160] - (0.7212A0A3 - 0.7212A0A9 - 0.8997D1) kJ;

[0161] In the above manner of the application, the coal is divided into high-sulfur coal and low-sulfur coal for separate treatment, thereby improving the accuracy of the calculation of the heat absorption of minerals.

[0162] The heat of coal is mainly provided by C and H in organic matter. From the perspective of the molecular structure of coal (the precise molecular structure of coal is unknown, and the present application is expressed by means of an organic matter molecular structure model), the combustion heat of carbon atoms in different chemical environments is different. Based on the combustion heat and the Gay-Lussac law, the heat of organic matter is calculated in combination with the molecular structure of coal. Coal has the characteristics of a polymer, and is a mixture of a series of "similar compounds" with similar but not completely identical molecular weights and molecular structures. The "similar compounds" are referred to as "basic structural units", which include regular parts and irregular parts. The regular parts are referred to as core structural units, which are composed of several or ten benzene rings, aliphatic rings, hydrogenated aromatic rings and heterocyclic rings (containing nitrogen, oxygen and sulfur). The irregular parts refer to alkyl side chains and various functional groups connected around the core structural units.

[0163] The present application simplifies the organic matter structure of coal, and only the core structural units and the alkyl side chains form the organic matter structure. The core structural units are connected to the alkyl side chains, the core structural units are connected by bridging bonds to form a two-dimensional structure, and the two-dimensional layers are connected by intermolecular forces to form a three-dimensional structure.

[0164] The present application constructs a series of core structural units, each of which is a derivative composed of different numbers of benzene rings. RN is defined to represent the number of benzene rings in the core structural unit, and RN takes an integer value of 1 to 12; the number of -CH (aromatic) functional groups in each core structural unit is a, and the number of -C- (aromatic) functional groups is b.

[0165] For example, a core structural unit composed of 3 benzene rings has RN = 3. If the 3 benzene rings are freely combined without considering the stability of the chemical structure, 2 isomers will be formed, as shown in Fig. 2 . Fig. 2There are 10 -CH (aromatic) functional groups and 4 -C- (aromatic) functional groups in the left core structural unit, i.e. a = 10 and b = 4. Fig. 2 There are 9 -CH (aromatic) functional groups in the right core structural unit, i.e. a = 9; the carbon atom at the center point in the definition structure is classified as a -C- (aromatic) functional group, i.e. there are only two kinds of functional groups, -CH (aromatic) and -C- (aromatic), in one structural core unit, the number of -C- (aromatic) functional groups is equal to the total number of carbon atoms minus the number of -CH (aromatic) functional groups; the total number of carbon atoms in this core structural unit is 13, so the number of -C- (aromatic) functional groups is 4, i.e. b = 4.

[0166] 76 core structural units can be obtained by freely combining 1 to 12 benzene rings without considering the stability of the chemical structure. The 76 core structural units can be accurately expressed by three parameters: the number of benzene rings (RN), the number of -CH (aromatic) functional groups (a), and the number of -C- (aromatic) functional groups (b), as shown in Table 6. For example, 5 benzene rings are freely combined to form a core structural unit (RN = 5), the number of -CH (aromatic) functional groups in the straight-chain arrangement core structural unit is 14 (a = 14), and the number of -C- (aromatic) functional groups is 8 (b = 8); the most compact arrangement core structural unit formed by 5 benzene rings has 11 -CH (aromatic) functional groups (a = 11) and 8 -C- (aromatic) functional groups (b = 8); therefore, the number of core structural units formed by 5 benzene rings is 4 (= 14-11+1); the number of -C- (aromatic) functional groups (b) in the straight-chain arrangement core structural unit and the most compact arrangement core structural unit is the same, so the other two core structural units between the straight-chain arrangement core structural unit and the most compact arrangement core structural unit have 8 -C- (aromatic) functional groups (b = 8), and the number of -CH (aromatic) functional groups decreases to 13 and 12, respectively, so the four core structural units can be represented by the parameters RN = 5, a = 14, b = 8; RN = 5, a = 13, b = 8; RN = 5, a = 12, b = 8; RN = 5, a = 11, b = 8.

[0167] Therefore, the number of core structural units formed by the free combination of different numbers of benzene rings is related to the number of -CH (aromatic) functional groups in the straight-chain arrangement core structural unit and the most compact arrangement core structural unit, i.e. the number of core structural units is equal to the difference between the a values of the two core structural units plus one.

[0168] The method for representing the number of -CH (aromatic) functional groups (a) and the number of -C- (aromatic) functional groups (b) in one core structure unit is as follows: when the value of RN is specified, the number of -CH (aromatic) functional groups (a) and the number of -C- (aromatic) functional groups (b) in the linearly arranged core structure unit and the most closely arranged core structure unit can be obtained from Table 6, and for other core structure units between the linearly arranged core structure unit and the most closely arranged core structure unit, the value of a decreases from the value of a in the linearly arranged core structure unit to the value of a in the most closely arranged core structure unit, the value of a is an integer, and the value of b is equal to the value of b in the linearly arranged core structure unit or the most closely arranged core structure unit. The number of core structure units corresponding to each RN and the values of a and b of the 76 core structure units are shown in Table 6.

[0169] Table 6

[0170]

[0171] The average number of carbon atoms in the alkyl side chain is defined as L1, and the value of L1 and the corresponding alkyl side chain functional group and combustion heat G5 are shown in Table 7, for example, when L1 = 0.5 or L1 = 0.9, the corresponding alkyl side chain functional group is methyl (-CH3), and the combustion heat G5 is -672.46 kJ / mol; the average number of bridging bonds is L2 (L2 >= 2); the sum of L1 and L2 is less than the number of -CH (aromatic) functional groups (a).

[0172] The combustion heat of an organic functional group is estimated by the average value of the combustion heat of simple compounds or the difference between the combustion heat of two compounds, for example:

[0173] The combustion heat of -CH (aromatic) functional group is equal to one sixth of the combustion heat of benzene, that is,

[0174] Δ c H m = -3267.54 kJ / mol ÷ 6 = -544.59 kJ / mol;

[0175] The combustion heat of -C- (aromatic) functional group is equal to the combustion heat of graphene, Δ c H m = -393.51 kJ / mol;

[0176] The combustion heat of -CH3 functional group is equal to the difference between the combustion heat of toluene and benzene, that is,

[0177] Δ c H m = (-3940) kJ / mol - (-3267.54) kJ / mol = -672.46 kJ / mol;

[0178] The combustion heat of the alkyl side chain is G5, and the combustion heat value of the organic functional group is shown in Table 7:

[0179] Table 7

[0180]

[0181] It can be understood that the definition of the x core structure units and y alkyl side chains in the organic matter in the coal, the core structure units form a two-dimensional layer through a bridging bond, and the two-dimensional layers form a three-dimensional structure through intermolecular forces. Assuming that the H atoms in the core structure unit are not substituted by the alkyl side chain and the bridging bond, it has a-(y / x+L2) -CH (aromatic) functional groups and (b+(y / x+L2)) -C- (aromatic) functional groups. In fact, the core structure unit is connected to the alkyl side chain and the bridging bond, so each core structure unit has y / x alkyl side chains on average, so the core structure unit has (a-(y / x+L2)) -CH (aromatic) functional groups and (b+(y / x+L2)) -C- (aromatic) functional groups. When the core structure unit forms a two-dimensional structure through a bridging bond, the core structure unit loses L2 (L2>=2) H atoms in two spatial dimensions, i.e. L2 -CH (aromatic) functional groups are converted into -C- (aromatic) functional groups. Its combustion heat:

[0182] Δ c H m =(-544.59)kJ / mol×(a-(y / x+L2))+(-393.51)kJ / mol×(b+(y / x+L2)

[0183] =-[(544.59a+393.51b)-151.08(y / x+L2)]kJ / mol;

[0184] Calculate the heat of the organic matter:

[0185] The average number of carbon atoms in the alkyl side chain is L1, and the molecular formula is C L1 H 2L1+1 Each alkyl side chain is composed of L1 C atoms and (2L1+1) H atoms. Each core structure unit contains (a+b) C atoms and (a-(y / x+L2)) H atoms. The organic matter has x core structure units and y alkyl side chains, so there are the following binary equations:

[0186] The amount of substance B of organic carbon in the coal 11 =n C -B 12 =(0.08333B1-B 12 ) mol = ((a+b)x+L1y) mol,

[0187] The amount of substance n of organic hydrogen in the coal H= B2 mol = ((a - (y / x + L2)) x + (2L1 + 1) y) mol,

[0188] x = (2B 11 - B2) / (a + 2b + L2), y = B 11 / L1 - [(2a + 2b) B 11 - (a + b) B2] / [(a + 2b) L1 + L1 L2];

[0189] The heat of combustion of the organic matter is equal to the heat of combustion of the core structural unit and the heat of combustion of the alkyl side chain, i.e. Q 有机质 = [(544.59a + 393.51b) - 151.08(y / x + L2)] kJ / mol x mol + G5 kJ / mol y mol

[0190] = (544.59a + 393.51b - 151.08L2) x + (G5 - 151.08) y kJ;

[0191] The heat of combustion of the organic matter is related to the number of benzene rings (RN) in the core structural unit, the number of -CH (aromatic) functional groups (a), the number of -C- (aromatic) functional groups (b), the average number of carbon atoms in the alkyl side chain (L1), the heat of combustion of the alkyl side chain functional group (G5), and the average number of bridging bonds (L2).

[0192] A set of parameters is determined by the following method:

[0193] ① According to Table 6, input all values of RN, a, and b, i.e. input 76 structures, as follows:

[0194] RN = 1, a = 6, b = 0; RN = 2, a = 8, b = 2; RN = 3, a = 10, b = 4; RN = 3, a = 9, b = 4; ...

[0195] RN = 7, a = 18, b = 12; RN = 7, a = 17, b = 12; RN = 7, a = 16, b = 12; RN = 7, a = 15, b = 12; ...

[0196] RN = 12, a = 19, b = 22; RN = 12, a = 18, b = 22; RN = 12, a = 17, b = 22; RN = 12, a = 16, b = 22.

[0197] (2) According to Table 7, input all values of L1, which are 0.5~1, 1.5~2, 2.5~3, 3.5~4, 4.5~5, 5.5~6, 6.5~7 (take one digit after the decimal point, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0) and the corresponding G5;

[0198] (3) Input all values of L2, which are 2=<L2<=(a-L1), take one digit after the decimal point, for example, 2, 2.1, 2.2,..., 3, 3.1, 3.2,..., (a-L1-2), (a-L1-1), (a-L1);

[0199] (4) Input the proximate analysis (calorific value, ash content and oxide content in ash) and elemental analysis data (carbon, hydrogen and sulfur content) of n groups (n>0) of dry base anthracite coal samples. The n groups of anthracite coal data should include coal sample data in Northeast China, North China, East China, Northwest China, Southwest China, Central South China and other regions, and the coal sample data in each region should be divided into intervals with a difference of no more than 0.3 kJ / g in calorific value, and each interval should contain at least 5 coal sample data.

[0200] (5) Input the organic matter calorific value calculation equation:

[0201] Q 有机质 =[(544.59a+393.51b)-151.08(y / x+L2)]kJ / mol×xmol+G5kJ / mol×ymol

[0202] =(544.59a+393.51b-151.08L2)x+(G5-151.08)ykJ;

[0203] x=(2B 11 -B2) / (a+2b+L2), y=B 11 / L1-[(2a+2b)B 11 -(a+b)B2] / [(a+2b)L1+L1L2];

[0204] (6) Input the mineral matter endothermic heat calculation equation:

[0205] High-sulfur coal:

[0206] Q 矿物质

[0207] =2.496A0A1 + 1.4715A0A2 - 10.4442A0A3 + 10.4442A0A9 + 3.1826A0A4 - 4.1912A0A8 + 2.8928A0A5 + 6.7356A0A6 + 5.4688A0A7 + 5.2216A0A8 + 0.5321A0A9 - 1.2365A0A 10 - (9.25D1 - 7.4118A0A3 + 7.4118A0A9) kJ;

[0208] Low-sulfur coal:

[0209] Q 矿物质

[0210] = 2.496A0A1 + 1.4715A0A2 - 13.0302D1 + 3.1826A0A4 - 4.1912A0A8 + 2.8928A0A5 + 6.7356A0A6 + 5.4688A0A7 + 5.2216A0A8 + 0.5321A0A9 - 1.2365A0A 10 - (0.7212A0A3 - 0.7212A0A9 - 0.8997D1) kJ;

[0211] ⑦Calculate the heat of n groups of dry base anthracite v = Q 有机质 - Q 矿物质 ;

[0212] Each group of parameters (RN, a, b, L1, G5, L2) will obtain the heat of n groups of dry coal samples, and the difference between the calculated heat and the oxygen bomb calorimeter measured heat is calculated, that is, the absolute error. The root mean square error (RMSE) and the complex determination coefficient (R 2 ) are introduced to evaluate the calculation accuracy of the heat calculation model. The closer the RMSE is to 0, the smaller the deviation between the calculated heat and the measured heat; the closer the R 2 is to 1, the better the linearity of the heat calculation model, and the higher the model fitting degree. Record which group of parameters has the smallest root mean square error (RMSE) and the highest complex determination coefficient (R 2 ), that is, the parameters for calculating the heat of anthracite.

[0213] Root mean square error: ;

[0214] Complex determination coefficient: ;

[0215] Residual sum of squares: ;

[0216] Total sum of squares: ;

[0217] y i : the measured heat value of the i th coal sample; : the calculated heat value of the i th coal sample; : the average of the measured heat values of the n coal samples; n: the total number of coal samples;

[0218] 8. Input the proximate analysis (ash content and oxide content in ash) and elemental analysis data (carbon, hydrogen, and sulfur content) of the unknown dry-basis anthracite coal sample;

[0219] 9. Bring the anthracite coal heat value calculation parameters (RN, a, b, L1, G5, L2) into step 5 to calculate the heat value of organic matter, and bring the data in step 8 into step 6 to calculate the heat absorption of mineral matter.

[0220] The heat value Q of the unknown dry-basis anthracite coal sample v = Q 有机质 - Q 矿物质 ;

[0221] The method for determining the parameters (RN, a, b, L1, G5, L2) for calculating the heat values of bituminous coal and lignite is the same as that for anthracite coal.

[0222] In summary, the present application can calculate the heat changes of mineral matter and S elements in coal, which are not only related to the contents of mineral metal elements (Si, Al, Fe, Ca, Mg, Na, K, Ti) and non-metal elements (S, P) in coal, but also related to the specific chemical reactions in which these elements are involved; and can calculate the heat changes of organic matter in coal, which are not only related to the average number of carbon atoms in the core structural unit and alkyl side chain, but also affected by mineral elements (inorganic carbon). At the same time, based on the idea of expressing that the heat value of coal is equal to the heat value of organic matter minus the heat absorption of mineral matter, the heat value of coal under constant volume (constant volume high heat value) is:

[0223] Q v = Q 有机质 - Q 矿物质 ;

[0224] Specifically, based on the calculation formula of the heat value of coal, the heat values of 30 groups of dry-basis bituminous coal from all over the country are calculated, and the proximate analysis and elemental analysis information of the 30 coal samples are as shown in Table 8:

[0225] Table 8

[0226]

[0227] The oxide content in the coal ash is shown in Table 9:

[0228]

[0229] A set of bituminous coal parameters RN=5, a=11, b=8, L1=3.9, G5=2562.46kJ / mol, L2=5.5 are used to calculate the heat of organic matter. At the same time, the sulfur (organic sulfur and inorganic sulfur) in the coal is classified, and the heat absorption of the mineral matter is calculated. The heat of 30 groups of bituminous coal, absolute error, relative error are shown in Table 10. The maximum absolute error, the maximum relative error are-0.59kJ / g, 2.27% respectively, the multiple determination coefficient (R 2 ) is 0.9927, and the root mean square error (RMSE) is 0.30kJ / g. The actual test case verifies that the scheme designed in the application has no significant error compared with the national standard test method.

[0230]

[0231] The application also provides a coal heat value calculation system, comprising:

[0232] A data acquisition module is configured to acquire basic data of a coal sample to be measured, including coal type, mass content of carbon (C), hydrogen (H), and sulfur (S) elements, and mass content of ash and mass percentage of oxides in the ash;

[0233] A parameter calling module is configured to call a pre-stored parameter set of a corresponding organic matter molecular structure model according to the coal type of the coal sample to be measured, wherein the parameter set includes core structure unit parameters (RN, a, b), average number of carbon atoms L1 of alkyl side chains, and corresponding combustion heat value G5 and average number L2 of bridging bonds;

[0234] A heat absorption calculation module is configured to divide high-sulfur coal or low-sulfur coal according to the amount-of-substance relationship of sulfur (S), iron (Fe), and titanium (Ti) elements in the coal; distribute mineral elements to a pre-set chemical reaction library; calculate the heat of each mineral according to the combustion heat and amount of substance of each reaction; and sum up the total heat absorption Q 矿物质 of the mineral matter.

[0235] A heat value calculation module is configured to determine the number of core structure units x and the number of alkyl side chains y by using the called parameter set of the organic matter molecular structure model and through the amount-of-substance conservation equation of organic carbon and organic hydrogen; and add the combustion heat value of the core structure unit and the combustion heat value G5 of the alkyl side chain to obtain the heat value Q 有机质 of the organic matter.

[0236] A comprehensive heat value module is configured to obtain the comprehensive heat value Q v based on the formula: Q 有机质 =Q 矿物质 -Q v .

[0237] Further, the coal calorific value calculation system of the present application comprises a parameter storage module for storing the organic matter molecular structure model parameter set corresponding to different coal types;

[0238] and further comprises a building module for building the organic matter molecular structure model parameter set, the building of the parameter set comprising:

[0239] Sample database building: obtaining basic data of a plurality of groups of dry base coal samples with known calorific values;

[0240] Parameter optimization: traversing the preset value combination of the core structure unit parameters (RN, a, b), the average number of carbon atoms L1 of the alkyl side chain, and the average number L2 of bridging bonds; for each parameter combination, calculating the calorific value calculation value of each coal sample in the sample database; taking the absolute error, the root mean square error (RMSE), and the multiple determination coefficient (R 2 ) between the calculation value and the measured value as evaluation indexes, and screening the optimal parameter combination;

[0241] Parameter storage: storing the optimal parameter combination in association with the corresponding coal type to form the parameter set.

[0242] Further, the core unit structure is composed of RN benzene rings, including (a-(y / x+L2)) -CH (aromatic) functional groups, (b+(y / x+L2)) -C- (aromatic) functional groups, and (a-(y / x+L2)) H atoms.

[0243] wherein: RN represents the number of benzene rings in the core structure unit, a represents the number of -CH (aromatic) functional groups in each core structure unit, b represents the number of -C- (aromatic) functional groups in each core structure unit; y is the total number of alkyl side chains, x is the total number of core structure units, y / x represents the average number of alkyl side chains connected to each core structure unit; L2 represents the average number of bridging bonds in each core structure unit; the number of benzene rings RN takes an integer from 1 to 12.

[0244] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be apparent to those of ordinary skill in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Accordingly, the application is not to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of calculating the calorific value of coal, characterized by, The method comprises the following steps: a data acquisition step of acquiring basic data of a coal sample to be measured, including a coal type, mass contents of carbon C, hydrogen H, and sulfur S elements, and a mass content of ash and a mass percentage of oxides in the ash; a parameter calling step of calling a pre-stored corresponding organic matter molecular structure model parameter set according to the coal type of the coal sample to be measured, the parameter set including core structure unit parameters RN and a and b, RN representing a number of benzene rings in a core structure unit, a and b representing numbers of -CH aromatic functional groups and -C- aromatic functional groups in a core structure unit without being substituted by alkyl side chains and bridging bonds, and L1 representing an average number of carbon atoms in an alkyl side chain and G5 representing a corresponding combustion heat value, and L2 representing an average number of bridging bonds; The heat absorption amount calculation step: according to the amount of substance relation of sulfur S, iron Fe and titanium Ti elements in the coal, high-sulfur coal or low-sulfur coal is divided; the mineral elements are distributed to the preset chemical reaction library, the heat of each reaction and the amount of substance are calculated to calculate the heat of each mineral, and the total heat absorption amount Q of the mineral is summed up 矿物质 ; Heat calculation step: using the called organic matter molecular structure model parameter set, through the amount of substance conservation equation of carbon element and hydrogen element, the number of core structure unit x and the number of alkyl side chain y are determined, and based on the combustion heat value of the core structure unit and the combustion heat value G5 of the alkyl side chain, the heat Q of the organic matter is obtained by adding 有机质 ; wherein, a combustion heat value of the core structure unit is calculated according to a combustion heat value formula of functional groups thereof as follows: Δ c H m = (-544.59) kJ / mol x (a - (y / x + L2)) + (-393.51) kJ / mol x (b + (y / x + L2)) =-[(544.59a+393.51b)-151.08(y / x+L2)]kJ / mol, wherein, RN represents a number of benzene rings in a core structure unit, RN is an integer from 1 to 12; a and b represent numbers of -CH aromatic functional groups and -C- aromatic functional groups in a core structure unit without being substituted by alkyl side chains and bridging bonds; x represents a total number of core structure units, y represents a total number of alkyl side chains, y / x represents an average number of alkyl side chains connected to a core structure unit, and L2 represents an average number of bridging bonds in a core structure unit; Calculate the heat of organic matter: Q 有机质= Delta c H m x x + G5 x y wherein: Δ c H m is the heat of combustion of the core structural unit, G5 is the heat of combustion of the alkyl side chain, x is the total number of core structural units, and y is the total number of alkyl side chains. The comprehensive heat generation amount calculation step is based on the formula: Q v = Q 有机质 - Q 矿物质 , to obtain the comprehensive heat generation amount Q v ; the organic matter structure of the coal is composed of only core structure units and alkyl side chains, the core structure units are connected to the alkyl side chains, the core structure units are connected to each other through bridging bonds to form a two-dimensional structure, and the two-dimensional layers are connected to each other through intermolecular forces to form a three-dimensional structure; one alkyl side chain is composed of L1 carbon atoms and 2L1+1 hydrogen atoms; and one core structure unit contains a+b carbon atoms and a-(y / x+L2) hydrogen atoms.

2. The coal calorific value calculation method according to claim 1, characterized by, The pre-stored organic matter molecular structure model parameter set is called, and the establishment of the parameter set comprises the following steps: a sample database establishment step of acquiring basic data of a plurality of dry base coal samples with known heat values; Parameter optimization step: traverse preset value combinations of core structure unit parameters RN and a and b, average carbon atom number L1 of alkyl side chain, and average number L2 of bridging bonds; for each parameter combination, calculate the calculated calorific value of each coal sample in the sample database; take the absolute error, root mean square error RMSE and complex determination coefficient R between the calculated value and the measured value as the evaluation index, and screen the optimal parameter combination 2 Take the absolute error, root mean square error RMSE and complex determination coefficient R between the calculated value and the measured value as the evaluation index, and screen the optimal parameter combination a parameter storage step of storing the optimal parameter combination in association with a corresponding coal type to form the parameter set.

3. The coal calorific value calculation method according to claim 2, characterized by, The coal type includes anthracite, bituminous coal and lignite; the mass content of carbon C, hydrogen H and sulfur S is respectively represented by B1, B2 and D1, and the mass content of ash is represented by A0; the oxides in the ash include silicon dioxide, di-aluminum trioxide, di-iron trioxide, calcium oxide, magnesium oxide, sodium oxide, potassium oxide, di-phosphorus pentoxide, titanium dioxide and sulfur trioxide, and the mass percentage of the oxides in the ash is respectively represented by A1-A 10 .

4. The coal calorific value calculation method according to any one of claims 1 to 3, characterized by, The high-sulfur coal or low-sulfur coal is divided according to a quantity-of-substance relationship of sulfur S, iron Fe, and titanium Ti elements in the coal, and specifically comprises the following steps: Fe and Ti elements in the coal preferentially form the compound FeTiO3, and the remaining Fe and S form the compound FeS2. Comparing the amounts of Fe and S at this time, if the amount of S is higher than that of Fe: (n Fe -n FeTiO3 )=<0.5n S , the coal is classified as high-sulfur coal, and the remaining S is allocated to organic S; If S is lower than the amount of substance of Fe: (n Fe -n FeTiO3 )> 0.5n S , the coal is classified as low-sulfur coal, and the remaining Fe forms the compound FeCO3.

5. The coal calorific value calculation method according to claim 4, characterized by, The reactions in the chemical reaction library include: decomposition of kaolinite Al2Si2O5(OH)4 into SiO2, Al2O3, and H2O, Illite K 0.8 Al2(Si,Al)4O 10 (OH)2decomposes into K2O, Al2O3, SiO2and H2O, oxidation of FeS2 into Fe2O3 and SO2, decomposition of CaCO3 into CaO and CO2, decomposition of MgCO3 into MgO and CO2, oxidation of FeTiO3 into Fe2O3 and TiO2.

6. The coal calorific value calculation method according to claim 1, characterized by, The quantity-of-substance conservation equations of carbon elements and hydrogen elements include: a quantity of organic carbon in the coal: B 11 =n C -B 12 =(B1g÷12g / mol)-B 12 mol=(0.08333B1-B 12 )mol=((a+b)x+L1y)mol, a quantity of organic hydrogen in the coal: n H = B2g ÷ 1 g / mol = B2 mol = ((a - (y / x + L2)) x + (2L1 + 1) y) mol, Wherein, a represents the number of -CH aromatic functional groups of a core structural unit when it is not substituted by alkyl side chain and bridging bond; b represents the number of -C- aromatic functional groups of a core structural unit when it is not substituted by alkyl side chain and bridging bond; x is the total number of core structural units, y is the total number of alkyl side chains; L1 represents the average number of carbon atoms of the alkyl side chain connected to a core structural unit; L1 has a value of 0.5-1, 1.5-2, 2.5-3, 3.5-4, 4.5-5, 5.5-6, 6.5-7, and the value is accurate to one decimal place; L2 represents the average number of bridging bonds of a core structural unit; B1 is the mass content of element C, B 11 is the amount of substance of organic carbon, B 12 is the amount of substance of inorganic carbon; the amount of substance of organic hydrogen in the dried base coal sample is equal to element H; B2 is the mass content of element H.

7. A coal calorific value calculation system characterized by comprising: The method comprises the following steps: a data acquisition module for acquiring basic data of a coal sample to be measured, including a coal type, mass contents of carbon C, hydrogen H, and sulfur S elements, and a mass content of ash and a mass percentage of oxides in the ash; The parameter calling module is configured to call a pre-stored corresponding organic matter molecular structure model parameter set according to the coal type of the coal sample to be tested, the parameter set including core structure unit parameters RN and a and b, an average number of carbon atoms L1 of an alkyl side chain and a corresponding combustion heat value G5, and an average number of bridging bonds L2; RN represents the number of benzene rings in a core structure unit; when a core structure unit is not substituted by an alkyl side chain and a bridging bond, the number of -CH aromatic functional groups and -C aromatic functional groups thereof are a and b, respectively; The heat absorption calculation module is used to classify coal into high-sulfur or low-sulfur coal based on the molar relationships of sulfur (S), iron (Fe), and titanium (Ti). It allocates mineral elements to a pre-defined chemical reaction library, calculates the heat of each mineral based on the heat of combustion and molar amounts of each reaction, and sums the results to obtain the total heat absorption Q of the minerals. 矿物质 ; The heat release calculation module is configured to determine the number of core structure units x and the number of alkyl side chains y by using the called parameter set of the organic matter molecular structure model, through the amount of substance conservation equation of carbon elements and hydrogen elements, and to obtain the heat release Q of the organic matter by adding the combustion heat value of the core structure units and the combustion heat value G5 of the alkyl side chains 有机质 ; wherein the combustion heat value of the core structure unit is calculated according to a combustion heat value calculation formula of the functional groups thereof as follows: Δ c H m = (-544.59) kJ / mol x (a - (y / x + L2)) + (-393.51) kJ / mol x (b + (y / x + L2)) = - [(544.59a + 393.51b) - 151.08(y / x + L2)] kJ / mol, wherein RN represents the number of benzene rings in a core structure unit, RN is an integer from 1 to 12; when a core structure unit is not substituted by an alkyl side chain and a bridging bond, the number of -CH aromatic functional groups and -C aromatic functional groups thereof are a and b, respectively; x is the total number of core structure units, y is the total number of alkyl side chains, y / x represents the average number of alkyl side chains connected to a core structure unit; and L2 represents the average number of bridging bonds in a core structure unit. Calculate the heat of organic matter: Q 有机质= Δ c H m × x + G5 x y wherein: Δ c H m is the heat of combustion of the core structural unit, G5 is the heat of combustion of the alkyl side chain, x is the total number of core structural units, and y is the total number of alkyl side chains. A comprehensive heat generation module for obtaining a comprehensive heat generation Q v =Q 有机质 -Q 矿物质 , based on the formula: v ; The organic matter structure of coal is composed of only core structure units and alkyl side chains, the core structure units are connected to the alkyl side chains, the core structure units form a two-dimensional structure through bridging bonds, and the two-dimensional layers form a three-dimensional structure through intermolecular forces; one alkyl side chain is composed of L1 C atoms and 2L1+1 H atoms; and one core structure unit contains a+b C atoms and a-(y / x+L2) H atoms.

8. The coal calorific value calculation system according to claim 7, characterized by The parameter storage module is configured to store the organic matter molecular structure model parameter sets corresponding to different coal types. The establishment module is configured to construct the organic matter molecular structure model parameter set, and the construction of the parameter set includes: Sample database establishment: obtaining basic data of a plurality of groups of dry base coal samples with known calorific values; Parameter optimization: traverse preset value combinations of core structure unit parameters RN and a and b, average number of carbon atoms L1 of alkyl side chain, and average number of bridging bonds L2; for each parameter combination, calculate the calculated calorific value of each coal sample in the sample database; calculate the absolute error, root mean square error RMSE and complex determination coefficient R between the calculated value and the measured value 2 As an evaluation index, the optimal parameter combination is screened out; Parameter storage: storing the optimal parameter combination in association with the corresponding coal type to form the parameter set.

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