CN117660022A - Thermal control deoxidizing inhibitor and formula determination method thereof - Google Patents
Thermal control deoxidizing inhibitor and formula determination method thereof Download PDFInfo
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- 239000003112 inhibitor Substances 0.000 title claims abstract description 22
- 238000000034 method Methods 0.000 title claims abstract description 18
- 239000000463 material Substances 0.000 claims abstract description 33
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 31
- 229910017053 inorganic salt Inorganic materials 0.000 claims abstract description 31
- 239000000523 sample Substances 0.000 claims abstract description 29
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims abstract description 20
- 238000004364 calculation method Methods 0.000 claims abstract description 19
- XYQRXRFVKUPBQN-UHFFFAOYSA-L Sodium carbonate decahydrate Chemical compound O.O.O.O.O.O.O.O.O.O.[Na+].[Na+].[O-]C([O-])=O XYQRXRFVKUPBQN-UHFFFAOYSA-L 0.000 claims abstract description 15
- 238000002474 experimental method Methods 0.000 claims abstract description 15
- 229940050906 magnesium chloride hexahydrate Drugs 0.000 claims abstract description 15
- DHRRIBDTHFBPNG-UHFFFAOYSA-L magnesium dichloride hexahydrate Chemical compound O.O.O.O.O.O.[Mg+2].[Cl-].[Cl-] DHRRIBDTHFBPNG-UHFFFAOYSA-L 0.000 claims abstract description 15
- WRUGWIBCXHJTDG-UHFFFAOYSA-L magnesium sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Mg+2].[O-]S([O-])(=O)=O WRUGWIBCXHJTDG-UHFFFAOYSA-L 0.000 claims abstract description 15
- 229940061634 magnesium sulfate heptahydrate Drugs 0.000 claims abstract description 15
- 229940018038 sodium carbonate decahydrate Drugs 0.000 claims abstract description 15
- 239000000843 powder Substances 0.000 claims abstract description 14
- 150000004677 hydrates Chemical class 0.000 claims abstract description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229960002337 magnesium chloride Drugs 0.000 claims abstract description 10
- 229910001629 magnesium chloride Inorganic materials 0.000 claims abstract description 10
- 238000004088 simulation Methods 0.000 claims abstract description 5
- 238000006243 chemical reaction Methods 0.000 claims description 48
- 230000000694 effects Effects 0.000 claims description 15
- 239000003795 chemical substances by application Substances 0.000 claims description 13
- 238000001938 differential scanning calorimetry curve Methods 0.000 claims description 13
- 238000010521 absorption reaction Methods 0.000 claims description 8
- 238000009472 formulation Methods 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 238000011160 research Methods 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 6
- -1 ferric oxide trihydrate Chemical class 0.000 claims description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 5
- 238000005457 optimization Methods 0.000 claims description 5
- 230000007246 mechanism Effects 0.000 claims description 4
- 230000007704 transition Effects 0.000 claims description 4
- 239000005909 Kieselgur Substances 0.000 claims description 3
- 230000004888 barrier function Effects 0.000 claims description 3
- 230000008901 benefit Effects 0.000 claims description 3
- 230000001360 synchronised effect Effects 0.000 claims description 3
- 230000004913 activation Effects 0.000 claims description 2
- 239000007795 chemical reaction product Substances 0.000 claims description 2
- 239000003245 coal Substances 0.000 abstract description 30
- 238000002485 combustion reaction Methods 0.000 abstract description 16
- 230000002269 spontaneous effect Effects 0.000 abstract description 15
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 11
- 229910052760 oxygen Inorganic materials 0.000 abstract description 11
- 239000001301 oxygen Substances 0.000 abstract description 11
- 230000002265 prevention Effects 0.000 abstract description 8
- 239000012782 phase change material Substances 0.000 abstract description 2
- 230000000979 retarding effect Effects 0.000 abstract 1
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- 230000002195 synergetic effect Effects 0.000 description 5
- 239000002131 composite material Substances 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- QHFQAJHNDKBRBO-UHFFFAOYSA-L calcium chloride hexahydrate Chemical compound O.O.O.O.O.O.[Cl-].[Cl-].[Ca+2] QHFQAJHNDKBRBO-UHFFFAOYSA-L 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000113 differential scanning calorimetry Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- RSIJVJUOQBWMIM-UHFFFAOYSA-L sodium sulfate decahydrate Chemical compound O.O.O.O.O.O.O.O.O.O.[Na+].[Na+].[O-]S([O-])(=O)=O RSIJVJUOQBWMIM-UHFFFAOYSA-L 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 238000002076 thermal analysis method Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000009614 chemical analysis method Methods 0.000 description 1
- 150000003841 chloride salts Chemical class 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000004455 differential thermal analysis Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000008261 resistance mechanism Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Abstract
The invention discloses a thermal control deoxidizing inhibitor and a formula determining method thereof, belonging to the technical field of coal spontaneous combustion prevention and control; comprises reduced iron powder, diatomite, magnesium chloride and inorganic salt hydrate; inorganic salt hydrates include sodium carbonate decahydrate, magnesium chloride hexahydrate, and magnesium sulfate heptahydrate; the formula determination is that firstly, sample materials of inorganic salt hydrates are selected for differential thermal experiments to obtain thermodynamic data of various inorganic salt hydrates; finally determining the thermal control material to be selected; then performing simulation calculation on the finally determined thermal control material to obtain the optimal proportion of the sample material; the deoxidizing retarder is mixed with the inorganic salt hydrate phase-change material to prevent spontaneous combustion of coal, has the function of 'coal oxygen temperature' three retarding, has wide application range, and can realize effective treatment of spontaneous combustion fire of coal mine.
Description
Technical Field
The invention belongs to the technical field of coal spontaneous combustion prevention and control, and relates to a thermal control deoxidizing type stopping agent and a formula determination method thereof.
Background
The coal seam occurrence condition and the geological structure of China are complex and various, disaster accidents occur frequently, and the fire disaster problem caused by spontaneous combustion of coal is particularly remarkable. The essential characteristics of spontaneous combustion of coal are active groups and O in the coal 2 The combination generates a compound reaction to release and accumulate heat, and the temperature rises to cause a chain reaction.
The scholars at home and abroad develop a great deal of research work on the aspects of coal fire hazard occurrence mechanism, mine fire prevention and extinguishing materials such as physical, chemical, physical and chemical synergistic resistance mechanism and the like, and form a mature mine fire prevention and extinguishing system. However, the mine fire prevention and control situation in China is still severe, and the mine fire prevention and extinguishing material theoretical research and the fire prevention and extinguishing technical system still need to be continuously perfected. The deoxidizing agent inhibits spontaneous combustion of coal by physical actions such as oxygen isolation, oxygen reduction and the like. The most commonly used deoxidizing inhibitor is an iron deoxidizing agent, consists of reduced iron powder, chloride salt and diatomite, and has the advantages of low price, simple preparation, less pollution and the like.
The biggest disadvantage of deoxidizing retarders is that they can develop exothermic phenomena during the process. The deoxidizer itself is more reducing than coal to rob the environment of oxygen reacting with the coal, and the stronger reducing tends to mean a greater exotherm. This heat tends to be counterproductive if not well handled.
Disclosure of Invention
The invention overcomes the defects of the prior art and provides a thermal control deoxidizing inhibitor and a formula determining method thereof; so as to achieve the purpose of temperature control.
In order to achieve the above purpose, the present invention is realized by the following technical scheme.
A thermal control deoxidizing inhibitor comprises reduced iron powder, diatomite, magnesium chloride and inorganic salt hydrate; the inorganic salt hydrate comprises sodium carbonate decahydrate, magnesium chloride hexahydrate and magnesium sulfate heptahydrate; the mass ratio of each component is reduced iron powder: diatomaceous earth: magnesium chloride: sodium carbonate decahydrate: magnesium chloride hexahydrate: magnesium sulfate heptahydrate = 10:4:1: 1.8-2.5: 0.4-1: 0.8 to 1.5.
Preferably, the temperature range suitable is 25℃to 150 ℃.
Reduced iron powder and O 2 A chemical reaction occurs; reduced iron powder and O 2 The chemical reaction process is as follows:
2Fe-4e - =2Fe 2+ (1)
O 2 +2H 2 O+4e - =4OH - (2)
Fe 2 ++2OH - =Fe(OH) 2 (3)
Fe(OH) 2 +O 2 +2H 2 O=4Fe(OH) 3 →[Fe 2 O 3 ·nH 2 O] (4)；
the magnesium chloride is a salt with stopping performance;
the diatomite can increase the compactness of the deoxidizer and fill the gaps of the pores of the coal body;
the inorganic salt hydrate is one or more of sodium sulfate decahydrate, sodium carbonate decahydrate, magnesium chloride hexahydrate, calcium chloride hexahydrate and magnesium sulfate heptahydrate, and the effect of cooling is achieved through phase-change heat absorption of the hydrate.
The action mechanism adopted by the invention is as follows: the metal ions contained in the inorganic salt and the active groups in the coal N, S, P form a coordination structure, so that the chemical reaction activity of the coal and oxygen can be reduced, and the chemical reaction is oxygen blocking; the reducing metal powder in the stopping agent reacts with oxygen to consume O in the surrounding environment 2 This is "oxygen reduction"; the inorganic salt hydrate absorbs heat through phase change and reduces the temperature, which is 'cooling'.
A method for determining a formulation of a thermally controlled deoxidizing retarder comprising the steps of:
1) Selecting sample materials of inorganic salt hydrates for carrying out differential thermal experiments to obtain thermodynamic data of various inorganic salt hydrates; analyzing the heat shielding effect of the deoxidizing inhibitor after adding the inorganic salt hydrate and the heat absorption benefits of various inorganic salt hydrates, and finally determining the heat control material to be selected;
2) And performing simulation calculation on the finally determined thermal control material to obtain the optimal ratio of sample materials: and fitting a DSC curve of the sample material by using Origin software to form a unitary four-time equation, using material studio software to simulate and calculate the heat release amount of the deoxidizing type inhibitor, integrating the heat release amount to obtain the heat release amount of the sample material, converting the heat release amount of the deoxidizing type inhibitor into a mathematical problem, taking the heat release amount of the deoxidizing type inhibitor and the heat release amount of the sample material as the center, and carrying out optimization calculation by using the equation to obtain the optimal proportion of the thermal control material, thereby finally obtaining the optimal proportion range of the deoxidizing type inhibitor controlled by heat.
Preferably, the optimization calculation of the column equation described in step 2) is performed using Python software.
Preferably, in step 1), a synchronous thermal analyzer is used for carrying out a heat shielding law research experiment on the sample, thermodynamic data of various inorganic salt hydrates are obtained through carrying out a differential thermal experiment, and the data are derived and plotted.
Preferably, the heat release amount calculating method comprises the following steps:
using the transition state theory of Eyring, the reaction rate constant equation is written as thermodynamically based, i.eAnd ，
k TST : a reaction rate constant;: degeneracy of the reaction path; k (k) B : a boltzmann constant; t: kelvin temperature; h: planck constant; r: molar gas constant; p (P) 0 : pressure intensity; an: molecular reaction; Δn=n-1; />: standard state activation free energy; whereby k will be directly determined by the free energy barrier to predict the reaction rate constant k for each temperature point, and then +_ according to the reaction rate equation>R: reaction rate; k: the reaction rate constant, which varies with temperature; />、/>Assuming that the reaction occurs in a fixed volume of solution, the molar concentration of substance A, B can be expressed in terms of moles of substance A, B per unit area when the reaction occurs in a certain range; index a and b: the number of reaction stages, depending on the reaction mechanism;
the reaction rate r of each temperature point is obtained, the reaction mass of each temperature point is calculated according to the molar mass of the reaction product, and finally the heat released by the reaction of the reduced iron powder at each temperature is calculated according to the fact that the heat released by the generated 1mol of ferric oxide trihydrate is 824.2KJ, the consumed iron powder is 2mol and the reaction heat converted into iron powder of unit mass is 7.36 KJ/g.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention mixes the traditional deoxidizing retarder with the inorganic salt hydrate phase-change material to prevent spontaneous combustion of coal, provides a solution for eliminating oxidation heat release of the deoxidizing retarder, and provides a new method for preventing spontaneous combustion of coal;
(2) The preparation method is simple to operate, and the prepared thermal control deoxidizing type composite stopping agent for preventing spontaneous combustion of coal has three stopping effects of 'coal oxygen temperature', and has three effects of preventing spontaneous combustion of coal: firstly, preventing active groups of coal from oxidizing; second, absorb the oxygen around the residual coal; thirdly, the inorganic compound absorbs heat through phase change, thereby achieving the effect of cooling.
(3) The invention can be applied to underground goafs and roadway fissure development coal walls and other places which are easy to self-ignite, has wide application range, can also use a thermal control deoxidization type composite stopping agent in the aspect of transportation of ground easy to self-ignite coal, and can provide more selectable fire prevention and extinguishing technical means for finally realizing effective treatment of coal mine self-igniting fire.
Drawings
FIG. 1 is a graph of heat flux for all samples of example 1;
FIG. 2 is a graph showing the contrast of DSC curve fitting to a unitary cubic equation;
FIG. 3 is a graph showing the contrast of DSC curve fitting to a unitary fourth-order equation;
FIG. 4 is a graph showing the contrast of DSC curve fitting to a unitary quintic equation;
FIG. 5 is a diagram of the exotherm of a deoxidizing retarder;
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the invention is further described in detail by combining the embodiments and the drawings. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. The following describes the technical scheme of the present invention in detail with reference to examples and drawings, but the scope of protection is not limited thereto.
The following examples are the preparation steps, corresponding thermal analysis experiments, and related calculations of a thermally controlled deoxidizing compound retarder for preventing spontaneous combustion of coal. The invention mainly adopts differential scanning calorimetry (Differential scanning calorimetry, DSC). Differential thermal analysis is a common material science and chemical analysis technique that can be used to study the thermal properties and thermal decomposition behavior of materials. The endothermic or exothermic behavior of DSC is typically indicative of the absorption or release of heat by the sample, and analysis of the experimental data results may yield more information about the sample during heating.
Example 1
The preparation, heat shielding law research and formula calculation of the thermal control deoxidizing type composite stopping agent for preventing coal spontaneous combustion comprise the following steps:
step 1 sample preparation
A deoxidizing composite inhibitor for preventing spontaneous combustion of coal is prepared from reduced iron powder, diatomite, magnesium chloride and inorganic salt hydrate. The addition amounts of the components in the heat control deoxidizing inhibitor are as follows according to the mass ratio of iron to diatomite to magnesium chloride when a differential heat experiment is carried out: inorganic salt hydrate = 10:4:1:15.
the deoxidized retarder A is prepared by weighing 3.333mg of reduced iron powder, 1.333mg of diatomite and 0.333mg of magnesium chloride by an electronic day and mixing the materials by grinding. The differential thermal experiments are carried out in five groups in total, each group of samples is added with 5mg of sodium sulfate decahydrate, 5mg of sodium carbonate decahydrate, 5mg of magnesium chloride hexahydrate, 5mg of calcium chloride hexahydrate and 5mg of magnesium sulfate heptahydrate on the basis of adding the deoxidizing inhibitor A, and the samples are fully ground and mixed to obtain five groups of samples to be detected, and the samples are a sample A1, a sample A2, a sample A3, a sample A4 and a sample A5 in sequence.
Step 2 endothermic Effect study of thermal control Material
The sample was subjected to a thermal analysis experiment using a synchronous thermal analyzer model NETZSCH STA 449F5, the heating rate was set to 5 ℃/min in the data software, the initial temperature was normal temperature 25 ℃, and the termination temperature was 600 ℃. In order to avoid heat taken away by air flow, the experiment adopts static combustion and does not adopt an air source for air supply. After heating to the final temperature, the test is ended, and after the thermocouple is cooled to below 200 ℃, the instrument is closed. The data from the derived experiments are plotted as in figure 1. Fig. 1 is a DSC profile for all sample materials.
The DSC data can directly reflect the absorption degree of each inorganic salt hydrate on the oxidation and heat release of deoxidizer reduced iron powder, and the heat shielding effect of each inorganic salt hydrate can be intuitively found through the DSC data longitudinal comparison among all samples, so that a proper heat control material is preferable.
As can be seen from fig. 1, during the low temperature oxidation stage (25 ℃ to 150 ℃), the endothermic peak of sample A1 appears first, while also having the shortest duration. Sample A2 shows an endothermic peak immediately following A1, and the peak area is much larger than A1. Sample A4 was the third to occur endothermic peak, but its peak was lower than all the other samples. The sample A5 endothermic peak occupies the very middle of the partial enlarged graph, with its peak maximum. The endothermic peak of sample A3 appears the latest and peaks at 140 ℃. Therefore, the samples A2, A3 and A5 have better effect in the low-temperature oxidation stage, and the best effect can be obtained by combining and collocating.
The five inorganic salt hydrates are analyzed through a differential scanning calorimetric experiment to realize heat shielding effect, and researches show that sodium carbonate decahydrate, magnesium chloride hexahydrate and magnesium sulfate heptahydrate are excellent heat control materials under the temperature condition of 25-150 ℃. Specific proportioning calculation is carried out on the added three inorganic salt hydrated salts, namely, sodium carbonate decahydrate, magnesium chloride hexahydrate and magnesium sulfate heptahydrate.
Step 3 simulation calculation of the formulation of the thermally controlled deoxidizing retarder
The superior heat control material sodium carbonate decahydrate, magnesium chloride hexahydrate and magnesium sulfate heptahydrate selected in the step 2 are subjected to combined synergistic endothermic effect. In the combined heat absorption process of the three inorganic salt hydrated salts, the content ratio of each component is calculated as follows:
(1) DSC curves of the three thermal control materials at the low temperature oxidation stage were fitted to polynomial equations using origin software. Comparing the effects of the fitted unitary cubic equation (see fig. 2) and the unitary quintic equation (see fig. 4), the result of the unitary quaternary equation (see fig. 3) is the most fit to the actual, so that the better unitary quaternary equation is selected for calculation. The DSC curve equations of the three thermal control materials after being fitted by software are respectively as follows:
curve equation y1= -7.86667 + 0.48384 x-0.00864 x for sodium carbonate decahydrate 2 + 6.11053*10 - 5 x 3 -1.51643*10 -7 x 4 ；
Curve equation y2= -0.048+0.0184x-6.08335 x 10 for magnesium chloride hexahydrate -4 x 2 +7.73593*10 -6 x 3 -2.78243*10 -8 x 4 ；
Curve equation y3= 5.9024-0.38529 x+ 0.00843x for magnesium sulfate heptahydrate 2 -7.07156*10 -5 x 3 +1.99897*10 -7 x 4 。
(2) The DMol3 module in the Materials studio molecular simulation software is used for simulating free energy required by the reaction of iron and oxygen to generate ferric oxide, a GGA and BLYP functional combination mode is selected, a Frequency check box on a Properties tab is checked, vibration analysis is carried out after the structure optimization is converged, and the result can be used for calculating various thermodynamic data. After the simulation was completed, the correction of G at the limited temperature in the dmol3.Outmol document was added to the Total Energy of the reactant to give the free Energy of the reaction at the limited temperature. The free energy calculations and associated data relating to this experiment are shown in Table 1.
TABLE 1 calculation of free energy of reaction for deoxidized retarders
(3) Using Eyring's transition state theory (transition state theory, TST), the reaction rate constant equation is written in a form based on thermodynamic quantities, i.eK is directly determined by the free energy barrier to predict the reaction rate constant k of each temperature point, and then ++according to the reaction rate equation>Obtaining the reaction rate r of each temperature point, calculating the reaction mass of each temperature point according to the time and the molar mass, and finally generating 1mol of ferric oxide trihydrate according to the previous calculation, wherein the heat released by the ferric oxide trihydrate is 824.2KJ, the consumed iron powder is 2mol, and the reaction is converted into the iron powder with unit massThe heat was 7.36KJ/g, and the amount of heat evolved by the reaction of the iron powder at each temperature was calculated. (3) The related calculation data of the method are shown in Table 2, and finally, the data of the heat release of the iron powder at each temperature are plotted to obtain a deoxidizing inhibitor heat release diagram, which is shown in FIG. 5.
TABLE 2 deoxidizing retarder exotherm calculation
(4) According to the heat quantity to be absorbed by the thermal control material is the heat quantity emitted by the deoxidizing retarder, the formula is used for solving the proportion. As can be seen from fig. 5, the deoxidizing retarder releases heat in three stages according to the change in temperature, namely, almost no heat release stage, slow heat release stage and rapid heat release stage. The exothermic function equation of each section is calculated, the equation of the almost non-exothermic phase at the temperature of 25-79 ℃ is Z1= 134.95187-4.10225x, the equation of the slow exothermic phase at the temperature of 79-129 ℃ is Z2= 26690.2095-349.98248x, and the equation of the rapid exothermic phase at the temperature of 129-151 ℃ is Z3= 26690.2095-349.98248x. Therefore, the heat released by the three stages needs to be subjected to sectional heat absorption to obtain the consumption of the heat control materials required by each stage, and the consumption of the heat control materials is finally overlapped to obtain the total consumption of the heat control materials.
And (3) performing synergistic endothermic calculation on a DSC curve equation Y1 after fitting sodium carbonate decahydrate, a DSC curve equation Y2 after fitting magnesium chloride hexahydrate and a DSC curve equation Y3 after fitting magnesium sulfate heptahydrate, wherein the synergistic DSC curve is set to be y=ay1+by2+cy3, the dosage of sodium carbonate decahydrate is assumed to be a, the dosage of magnesium chloride hexahydrate is assumed to be b, the dosage of magnesium sulfate heptahydrate is assumed to be c, and the synergistic DSC curve Y is integrated to obtain an endothermic curve Y of the inorganic salt hydrate:
Y= (-7.86667a-0.048b+5.9024c)x + (0.24192a+0.0092b-0.192645c)x 2 + (-0.00288a-0.0002020785b+0.0028065c)x 3 +(2.0385175*10 -5 a+2.583245*10 -6 b-2.3701568*10 -5 c)x 4 + (-2.5332153660904477*10 -7 a-4.6478726*10 -8 b+3.996911803*10 -7 c)x 5 。
according to the following equation z1=y1, wherein a, b and c in Y take a1, b1 and c 1; z2=y2, wherein a, b, c in Y are a2, b2, c 2; the method comprises the steps that Z3=Y3, wherein a, b and c in Y are a3, b3 and c3, the conditions a, b and c are all required to be met and are not equal to 0, python software is used for calculating an optimal solution meeting the equation conditions, and an approximate calculation result is a1= 0.4493, b1=0.3356 and c1=0.0002; a2 = 3.6041, b2= 2.1823, c2= -1.8223×10 -7 The method comprises the steps of carrying out a first treatment on the surface of the a3 = 36.0901, b3= 4.6939, c3= 19.4181. Finally, the total amounts required for each stage are added to obtain the total amounts a=a1+a2+a3, b=b1+b2+b3, c=c1+c2+c3, a=40.1435, b=7.2188, c= 19.4183.
Because of errors in fitting DSC curve equations, approximate substitution of calculation results, experimental operation and the like, the proportioning range of three heat control materials by mass is given here, namely sodium carbonate decahydrate: magnesium chloride hexahydrate: magnesium sulfate heptahydrate= (1.8-2.5): (0.4-1): (0.8 to 1.5). The heat absorption effect can be guaranteed to be achieved by meeting the range, the problem of heat release of the original deoxidizing type stopping agent is solved, and the situation that coal spontaneous combustion occurs due to the use of the stopping agent is fundamentally prevented.
Finally, the thermal control deoxidizing inhibitor is prepared from the following components in percentage by weight: diatomaceous earth: magnesium chloride: sodium carbonate decahydrate: magnesium chloride hexahydrate: magnesium sulfate heptahydrate = 10:4:1: (1.8-2.5): (0.4-1): (0.8 to 1.5).
While the invention has been described in detail in connection with specific preferred embodiments thereof, it is not to be construed as limited thereto, but rather as a result of a simple deduction or substitution by a person having ordinary skill in the art to which the invention pertains without departing from the scope of the invention defined by the appended claims.
Claims (6)
1. The thermal control deoxidizing inhibitor is characterized by comprising reduced iron powder, diatomite, magnesium chloride and inorganic salt hydrate; the inorganic salt hydrate comprises sodium carbonate decahydrate, magnesium chloride hexahydrate and magnesium sulfate heptahydrate; the mass ratio of each component is reduced iron powder: diatomaceous earth: magnesium chloride: sodium carbonate decahydrate: magnesium chloride hexahydrate: magnesium sulfate heptahydrate = 10:4:1: 1.8-2.5: 0.4-1: 0.8 to 1.5.
2. A thermally controlled deoxidizing agent as claimed in claim 1, wherein the temperature range suitable is 25 ℃ to 150 ℃.
3. The method for determining the formulation of a thermally controlled deoxidizing agent as claimed in claim 1 or 2, comprising the steps of:
1) Selecting sample materials of inorganic salt hydrates for carrying out differential thermal experiments to obtain thermodynamic data of various inorganic salt hydrates; analyzing the heat shielding effect of the deoxidizing inhibitor after adding the inorganic salt hydrate and the heat absorption benefits of various inorganic salt hydrates, and finally determining the heat control material to be selected;
2) And performing simulation calculation on the finally determined thermal control material to obtain the optimal ratio of sample materials: and fitting a DSC curve of the sample material by using Origin software to form a unitary four-time equation, using material studio software to simulate and calculate the heat release amount of the deoxidizing type inhibitor, integrating the heat release amount to obtain the heat release amount of the sample material, converting the heat release amount of the deoxidizing type inhibitor into a mathematical problem, taking the heat release amount of the deoxidizing type inhibitor and the heat release amount of the sample material as the center, and carrying out optimization calculation by using the equation to obtain the optimal proportion of the thermal control material, thereby finally obtaining the optimal proportion range of the deoxidizing type inhibitor controlled by heat.
4. A method of determining the formulation of a thermally controlled deoxidizing agent as claimed in claim 3, wherein the optimization of the column equation in step 2) is performed using Python software.
5. The method for determining a formulation of a thermal control deoxidizing agent according to claim 3, wherein in step 1), a thermal shielding law research experiment is performed on the sample by using a synchronous thermal analyzer, thermodynamic data of various inorganic salt hydrates are obtained by performing a differential thermal experiment, and the data is derived and plotted.
6. The method for determining the formulation of a thermal control deoxidizing retarder of claim 3, wherein the method for calculating the amount of heat release comprises:
using the transition state theory of Eyring, the reaction rate constant equation is written as thermodynamic based, i.e., formula，
k TST : a reaction rate constant;: degeneracy of the reaction path; k (k) B : a boltzmann constant; t: kelvin temperature; h: planck constant; r: molar gas constant; p (P) 0 : pressure intensity; an: molecular reaction; Δn=n-1; />: standard state activation free energy; whereby k will be directly determined by the free energy barrier to predict the reaction rate constant k at each temperature point, and then based on the reaction rate equationR: reaction rate; k: the reaction rate constant, which varies with temperature; />、/>Assuming that the reaction occurs in a fixed volume of solution, the molar concentration of substance A, B can be expressed in terms of moles of substance A, B per unit area when the reaction occurs in a certain range; index a and b: the number of reaction stages, depending on the reaction mechanism;
the reaction rate r of each temperature point is obtained, the reaction mass of each temperature point is calculated according to the molar mass of the reaction product, and finally the heat released by the reaction of the reduced iron powder at each temperature is calculated according to the fact that the heat released by the generated 1mol of ferric oxide trihydrate is 824.2KJ, the consumed iron powder is 2mol and the reaction heat converted into iron powder of unit mass is 7.36 KJ/g.
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