Composite powder explosion inhibitor and design method and preparation method thereof

Abstract

The application relates to the technical field of explosion suppression, in particular to a composite powder explosion suppressant and a design method and a preparation method thereof. The composite powder explosion suppressant comprises the following components in parts by mass: 20-25 parts of aluminum oxide, 10-20 parts of magnesium oxide, 20-30 parts of silicon dioxide, 1-3 parts of cerium oxide, 10-15 parts of potassium bicarbonate, 10-15 parts of sodium bicarbonate, 3-8 parts of fumed hydrophobic white carbon black and 2-6 parts of talcum powder. The composite powder explosion suppressant has high explosion suppression efficiency; the metal oxide component screened through quantum chemistry calculation has good explosion suppression performance; the components in the composite powder explosion suppressant synergistically act, and hydrogen gas explosion can be effectively suppressed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of explosion suppression, in particular to a composite powder explosion suppressant and a design method and a preparation method thereof. BACKGROUND

[0002] Hydrogen energy is a clean and efficient, abundant source, widely used secondary energy, is considered to be one of the most potential alternative energy to traditional fossil fuels, can play an important role in dealing with energy crisis, global warming and other aspects, is an ideal carrier to promote large-scale utilization of renewable energy and an important starting point to realize green and low-carbon transformation of energy. However, due to the special physicochemical properties of hydrogen, such as wide explosion limit range, low ignition energy and fast laminar burning velocity, it has the characteristics of high flammability and explosiveness, and once leakage occurs, it is easy to induce explosion, causing casualties and property losses. Spraying explosion suppressant can suppress, interrupt or slow down the hydrogen explosion reaction chain, weaken the intensity of hydrogen explosion, and can also protect the place where the hydrogen concentration reaches the explosion limit, which is one of the means to prevent and control hydrogen explosion accidents.

[0003] A core problem involved in the development of explosion suppression technology is to develop or select appropriate explosion suppression materials for target combustible materials. The high reactivity of hydrogen poses stringent requirements for the development of suitable explosion suppressants, including explosion suppression efficiency, environmental friendliness, and cost.

[0004] Currently, hydrogen explosion suppression materials mainly based on ultra-fine water mist, inert gases (CO2, N2, etc.), halogenated hydrocarbons (heptafluoropropane, trifluoroiodomethane, etc.) and hydrocarbons (propane, ethylene, etc.) are studied, but the effect is not ideal, and there are disadvantages such as low explosion suppression efficiency, high cost and negative impact on the environment. Powder explosion suppressant is also widely used in gas explosion prevention field because of its low cost, green environmental protection, convenient storage and transportation, etc. However, due to the faster explosion reaction speed of hydrogen than common combustible gases such as methane (the main component of gas), traditional single powder explosion suppressant (ammonium phosphate salt dry powder, NaHCO3, KHCO3, etc.) is difficult to exert chemical explosion suppression efficiency, resulting in poor explosion suppression effect.

[0005] Therefore, it is necessary to provide a composite powder explosion suppressant with good explosion suppression effect. SUMMARY

[0006] To solve the above technical problems, the present application provides a design method of a composite powder explosion suppressant. The method designs a composite powder explosion suppressant with good explosion suppression effect from a theoretical point of view.

[0007] The technical problem to be solved by the present application is to provide a composite powder explosion suppressant and a preparation method thereof.

[0008] To achieve the above purpose, the present application adopts the following technical scheme:

[0009] A composite powder explosion inhibitor, by mass fraction, comprises the following components: 20-25 parts of alumina, 10-20 parts of magnesium oxide, 20-30 parts of silicon dioxide, 1-3 parts of cerium oxide.

[0010] Preferably two, the composite powder explosion inhibitor further comprises 10-15 parts of potassium bicarbonate, 10-15 parts of sodium bicarbonate, 3-8 parts of fumed hydrophobic white carbon black, and 2-6 parts of talc.

[0011] More preferably, the 90% particle size of the composite powder explosion inhibitor is less than or equal to 5μm, i.e. the composite powder explosion inhibitor is an ultra-fine composite powder explosion inhibitor.

[0012] The design method of the above-mentioned composite powder explosion inhibitor comprises the following steps:

[0013] S1: structure optimization and frequency analysis of the key elementary reactions in the application field of the composite powder explosion inhibitor to obtain the correct optimized configuration;

[0014] S2: single-point energy calculation of the correct optimized configuration to obtain the energy difference of the key elementary reactions;

[0015] S3: calculation of the effect of the powder on the total energy of the reaction system under the correct optimized configuration to obtain the energy difference of the key elementary reactions in the presence of the powder;

[0016] S4: comparison of the results of step S3 and the results of step S2 to obtain the ranking of the explosion suppression performance of the powder;

[0017] S5: screening to obtain the component formula of the composite powder explosion inhibitor according to the results of step S4.

[0018] Among them, the S1: structure optimization and frequency analysis of the key elementary reactions in the application field of the composite powder explosion inhibitor specifically comprises the following steps:

[0019] S11: structure optimization processing of the key elementary reactions in the application field of the composite powder explosion inhibitor, the structure optimization is specifically adjusting the geometry of the system until the total energy of the system reaches a local minimum value to obtain the optimized configuration;

[0020] S12: frequency analysis confirmation of the optimized configuration to obtain the correct optimized configuration.

[0021] Among them, the S3: calculation of the effect of the powder on the total energy of the reaction system under the correct optimized configuration specifically comprises the following steps:

[0022] S31: calculation of the single-point energy of the powder in isolation and the single-point energy of the powder in each state in the key elementary reactions;

[0023] S32: The single point energy obtained according to step S31 can obtain the reaction path energy difference under the condition of the existence of the powder.

[0024] The S5: screening the component formula of the composite powder explosion inhibitor according to the result of step S4 specifically comprises the following steps:

[0025] S51: obtaining the candidate powder with excellent explosion suppression performance according to the ranking result of step S4;

[0026] S52: performing secondary screening from two use dimensions of safety and economy, and finally obtaining the component formula of the composite powder explosion inhibitor balanced in performance, safety and cost.

[0027] The application field of the composite powder explosion inhibitor is to suppress hydrogen explosion.

[0028] The preparation method of the composite powder explosion inhibitor comprises the following steps:

[0029] S01: weighing each component raw material according to the proportion;

[0030] S02: drying the weighed raw material; the drying treatment condition is: temperature 60-80 DEG C, time 10-14h;

[0031] S03: performing dry compounding treatment on the dried raw material to obtain a composite powder; the ball milling method is adopted for dry compounding in this embodiment;

[0032] S04: performing coating modification treatment on the composite powder to obtain a coated modified powder;

[0033] S05: performing drying treatment on the coated modified powder obtained in step S04 again;

[0034] S06: performing screening treatment on the composite powder material obtained in step S05 to obtain an ultrafine composite powder explosion inhibitor with a particle size less than or equal to 5 microns; the screening treatment is to screen the composite powder material in a 3000-mesh filter screen.

[0035] Preferably, the coating modification treatment on the composite powder obtained in step S03 is specifically to put the composite powder obtained in step S03 into methyl hydrogen silicone oil for stirring treatment, wherein the mass of the methyl hydrogen silicone oil is 0.5-2% of the mass of the composite powder, the stirring speed is 200-400 r / min, and the stirring time is 30-60 min.

[0036] The beneficial effects of the present application are as follows:

[0037] (1) The design method of the composite powder explosion inhibitor of the present application is highly innovative; for the first time, the influence of metal oxide materials on the key elementary reactions of hydrogen combustion is systematically studied from the perspective of quantum chemical calculation, providing a theoretical basis for the selection of components of the explosion inhibitor, greatly saving experimental time and resources.

[0038] (2) The composite powder explosion inhibitor of the present application has high explosion suppression efficiency; the metal oxide components selected through quantum chemical calculation have good explosion suppression performance, and the components in the composite powder explosion inhibitor synergistically work together to effectively suppress hydrogen explosion.

[0039] (3) The composite powder explosion inhibitor of the present application is environmentally friendly and low in cost; the raw materials selected in the present application are common inorganic substances that are non-toxic and harmless, and will not have negative impact on the environment; the raw materials are widely available and low in price, and have good engineering application prospects.

[0040] (4) The composite powder explosion inhibitor of the present application has a simple preparation process: dry compounding technology is used for preparation, which is simple to operate and easy to realize industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is the IRC diagram of the key elementary reactions of hydrogen combustion in Example 1;

[0042] Figure 2 is a result graph of comparison of explosion overpressure-time curves before and after the composite powder explosion inhibitor prepared in Examples 2 to 4;

[0043] Figure 3 is a result graph of comparison of explosion overpressure rise rate-time curves before and after the composite powder explosion inhibitor of Examples 2 to 4;

[0044] Figure 4 is a result graph of comparison of explosion overpressure-time curves before and after the composite powder explosion inhibitor prepared in the comparative example and the composite powder explosion inhibitor prepared in Example 2.

[0045] Figure 5 is a result graph of comparison of explosion overpressure rise rate-time curves before and after the composite powder explosion inhibitor prepared in the comparative example and the composite powder explosion inhibitor prepared in Example 2. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the present application clearer and more apparent, the present application will be further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0047] The design method of the composite powder explosion inhibitor of the application first starts from the quantum chemistry calculation angle, systematically studies the influence of metal oxide materials on the key elementary reactions of hydrogen combustion, provides a theoretical basis for the component selection of the explosion inhibitor, greatly saves the experimental time and saves the resources.

[0048] The single-point energy refers to the calculated system electronic energy under the condition that the atomic nucleus position of the molecule is fixed. In the application, first, a calculation method (B3LYP-D3(BJ) / 6-31G(d,p)) is used to obtain the most stable spatial structure of the reactant, transition state and product, and then a more accurate calculation method (M06-2X / def2-TZVPP) is used to calculate the energy of the most stable spatial structure of the reactant, transition state and product. This energy is the "single-point energy". This is done to obtain more reliable energy data under acceptable calculation cost.

[0049] The energy change is the core index for evaluating the effect of the explosion inhibitor. By comparing the energy difference (e5-e3) of the key elementary reactions of hydrogen combustion with and without the explosion inhibitor (metal oxide), the intervention effect of the explosion inhibitor can be judged. If the energy change value of the reaction is significantly changed (for example, the reaction energy barrier is increased or the reaction heat is changed sharply) after adding the explosion inhibitor, it indicates that the explosion inhibitor can effectively intervene in the reaction, thereby having explosion inhibition potential.

[0050] Example 1

[0051] A design method of a composite powder explosion inhibitor, comprising the following steps:

[0052] S1: performing structure optimization and frequency analysis on the key elementary reactions in the application field of the composite powder explosion inhibitor. The correct optimized configuration obtained in step S1 is the most stable spatial structure of the reactant, transition state and product.

[0053] The composite powder explosion inhibitor of the present embodiment is applied in the field of inhibiting hydrogen explosion, so step S1 needs to perform structure optimization and frequency analysis on the key elementary reactions of hydrogen combustion.

[0054] In the step S1, the following steps are included:

[0055] S11: performing structure optimization on the key elementary reactions in the application field of the composite powder explosion inhibitor, wherein the structure optimization is specifically adjusting the geometry of the system until the total energy of the system reaches a local minimum value to obtain the optimized configuration;

[0056] S12: performing frequency analysis on the optimized configuration to obtain the correct optimized configuration.

[0057] "Structure optimization" is a computational process that seeks the lowest energy point in a system to determine its most stable geometric configuration. Frequency analysis of the optimized structure verifies its structural properties: the stable structures of reactants and products should have no imaginary frequencies, while the transition state structure should have exactly one imaginary frequency, indicating that it is an energy saddle point connecting the reactants and products. All optimized structures in this paper were confirmed through frequency analysis.

[0058] Specifically, structural optimization is the process of automatically finding the "most stable" geometric configuration of a molecule or system during computation. The computational program continuously adjusts the positions of atoms (bond lengths and angles) until the total energy of the system reaches a local minimum. The result of this optimization is the equilibrium configuration of reactants, products, and transition states.

[0059] Frequency analysis is a check on the optimized configuration. Its results serve two important purposes: first, confirming the structural properties. For reactants and products, their vibrational frequencies should all be real frequencies (positive values); for the transition state, there must be exactly one imaginary frequency (negative value), the direction of which corresponds to the direction of the reaction crossing the energy barrier. Second, it verifies that the transition state found is indeed the correct saddle point connecting the reactants and products.

[0060] In the present invention, the key elementary reactions of hydrogen combustion include:

[0061] R7, H2+O2→H+HO2;

[0062] R1, H+O2→O+OH;

[0063] R2, O+H2→H+OH;

[0064] R3, OH+H2→H+H2O.

[0065] Specifically, the B3LYP-D3(BJ) / 6-31G(d,p) functional and basis set were first used to perform structural optimization and frequency analysis on the key elementary reactions of hydrogen combustion H2+O2=H+HO2(R7), H+O2=O+OH(R1), O+H2=H+OH(R2), and H2+OH=H2O+H(R3).

[0066] like Figure 1 As shown, the potential energy curves of these four elementary reactions were verified by IRC (intrinsic reaction coordinate) calculation. Figure 1 The horizontal axis represents the reaction coordinate, the vertical axis represents the relative energy, and the highest point on each curve corresponds to the transition state structure of the reaction. Figure 1 S1 in the figure is the potential energy curve of the R7 reaction. Figure 1 S2 in the figure is the potential energy curve of the R1 reaction. Figure 1 S3 in the figure is the potential energy curve of the R2 reaction. Figure 1S4 in FIG. 1 is the potential energy curve of the R3 reaction.

[0067] The IRC calculation can confirm that the obtained transition state indeed connects the target reactants and products, and can also obtain the energy change information on the reaction path. Among them, R7 and R1 represent the chain initiation reaction in the hydrogen combustion process, and R2 and R3 represent the chain propagation reaction, which constitutes the key step in the hydrogen explosion reaction chain.

[0068] S2: Single-point energy calculation is performed on the correctly optimized configuration to obtain the energy difference of the key elementary reaction, i.e., the energy difference of the key elementary reaction under the condition that no additive (powder) is present.

[0069] In this embodiment, single-point energy calculation is performed on the optimized configuration using the M06-2X / def2-TZVPP functional and basis set. The results are shown in Table 1.

[0070] Table 1 Energy values of key elementary reactions in hydrogen combustion

[0071]

[0072] S3: Calculate the effect of different powders on the total energy of the reaction system under the correctly optimized configuration to obtain the energy difference of the key elementary reaction in the presence of the powder.

[0073] Specifically, step S3 includes the following steps:

[0074] S31: Calculate the single-point energy of the isolated powder and the single-point energy of the powder in each state in the key elementary reaction. The single-point energy is an energy value obtained by high-precision quantum chemical calculation, specifically, single-point energy calculation on a specific system at the M06-2X / def2-TZVPP functional and basis set level.

[0075] The single-point energy obtained in step S31 includes e1 to e5, e1 refers to the single-point energy of the isolated powder (metal oxide additive), which is the basic energy value of the additive itself. e2 refers to the total energy of the system when the metal oxide coexists with the reactants of the key elementary reaction of hydrogen combustion without forming interaction, e2 is equal to e1 (the energy of the metal oxide) plus the energy of the reactants. e3 refers to the system energy when the metal oxide and the reactants form a whole (i.e., form a complex), which is the energy after they interact and reach a stable structure. e4 refers to the total energy of the system when the metal oxide coexists with the product of the key elementary reaction without forming interaction, e4 is equal to e1 (the energy of the metal oxide) plus the energy of the product. e5 refers to the system energy when the metal oxide and the product form a whole (i.e., form a complex), which is the energy after they interact and reach a stable structure.

[0076] S32: The single point energy calculated in step S31 can be used to obtain the energy difference of the reaction path (e5-e3) in the presence of the powder. Further, step S32 also calculates the interaction energy between the metal oxide and the reactant (e3-e2) and the interaction energy between the metal oxide additive and the reaction product (e5-e4).

[0077] In this embodiment, the M06-2X / def2-TZVPP functional and basis set are used to analyze the change in the system energy in the presence of the additive (oxide) to evaluate the explosion suppression effect. The results are shown in Tables 2 to 5. Specifically,

[0078] e3-e2 reflects the interaction energy between the metal oxide and the reactant; e5-e4 represents the interaction energy between the metal oxide additive and the reaction product, and e5-e4 reflects the tendency and strength of the combination of the additive and the product; e5-e3 represents the energy difference of the reaction path in the presence of the additive (i.e., the energy difference of the key elementary reaction of hydrogen combustion in the presence of the metal oxide and in the absence of the metal oxide).

[0079] Table 2 Influence of the oxide on the hydrogen combustion elementary reaction R7

[0080]

[0081] Table 3 Influence of the oxide on the hydrogen combustion elementary reaction R1

[0082]

[0083] Table 4 Influence of the oxide on the hydrogen combustion elementary reaction R2

[0084]

[0085] Table 5 Influence of the oxide on the hydrogen combustion elementary reaction R3

[0086]

[0087] S4: The results of step S3 and the results of step S2 are compared to obtain the ranking of the explosion suppression performance of different powders; that is, the energy difference of the key elementary reaction in the presence of the powder obtained in step S3 and the energy difference of the key elementary reaction in the absence of the powder obtained in step S2 are compared, and the influence of the calculation results obtained in step S3 on the calculation results of step S2 is used to evaluate the explosion suppression performance of the powder.

[0088] The explosion suppression performance of the 12 metal oxides studied was evaluated by comparing the reaction energy differences (e5-e3) in the presence of each metal oxide. As shown in Table 1, for the chain initiation reaction R7 (H2+O2→H+HO2), the energy difference without additives is 1.76683 eV. Here, the "energy difference without additives" refers to the energy change in the pure hydrogen combustion reaction itself, without any external interference. This value serves as the baseline for evaluating explosion suppression effectiveness. By comparing e5-e3 with the baseline, we can determine the impact of the additive on the reaction process. If the e5-e3 value changes significantly from the baseline, it means that the metal oxide has profoundly altered the energy path of this key reaction. This alteration in the energy path is precisely the manifestation of the inhibitory effect of the explosion suppressant—it interacts with the reactants or products, making the original reaction more difficult or taking a different path, thereby interrupting or slowing the explosive chain reaction. Therefore, the greater the difference between e5-e3 and the baseline energy difference, the greater the additive's ability to interfere with the reaction and the better its potential explosion suppression performance.

[0089] Therefore, for reaction R7 (Table 2), the metal oxides that exhibit an inhibitory effect (i.e., change the reaction energy) are ranked according to their intervention intensity on the reaction (based on | (e5-e3) - (original reaction energy difference) |) as follows: NiO |(-6.47558)-1.76683|= 8.24241 eV > Al2O3 (7.50748) > SrO (7.34463) > ZnO(7.21692) > SnO2 (6.74359) > CuO (6.21306) > CeO2 (5.65147) > ZrO2 (5.01401) >MgO (3.37051) > SiO2 (3.34173) > K2O (3.22797) > Na2O (3.08280).

[0090] For the chain initiation reaction R1 (H+O2→O+OH) (Table 3), the energy difference in the absence of additives is -1.18003 eV (Table 1). The metal oxides that show an inhibitory effect are ranked according to their intervention intensity on the reaction as follows: ZnO (3.78751) > CuO(3.39274) > K2O (3.28335) > NiO (2.68974) > CeO2 (2.18254) > Na2O (1.71834) >SnO2 (1.68218) > Al2O3 (1.37471) > SrO (0.68214) > ZrO2 (0.59479) > MgO(0.21838) > SiO2 (0.16501).

[0091] For the chain growth reaction R2 (O+H2→H+OH) (Table 4), the energy difference in the absence of additives is 0.24860 eV (Table 1). The metal oxides that show an inhibitory effect are ranked according to their intervention intensity on the reaction as follows: Al2O3 (9.27961) > SrO(5.81402) > ZrO2 (5.66586) > Na2O (5.55965) > CeO2 (5.09664) > MgO (4.72040) >SnO2 (4.49494) > K2O (4.49384) > SiO2 (4.13261) > CuO (3.64492) > NiO(1.22673) > ZnO (0.80150).

[0092] For the chain growth reaction R3 (H2+OH→H2O+H) (Table 5), the energy difference in the absence of additives is -0.60019 eV (Table 1). The metal oxides that show an inhibitory effect are ranked according to their intervention intensity on the reaction as follows: Al2O3 (3.75234) >CuO (3.66657) > K2O (1.59281) > ZrO2 (1.38903) > MgO (1.36654) > ZnO (1.32401)> CeO2 (1.20584) > Na2O (1.19086) > SiO2 (1.13358) > SrO (0.86793) > NiO(0.58319) > SnO2 (0.46371).

[0093] Based on the analysis of the above four key elementary reaction systems, a comprehensive inhibition performance evaluation of each metal oxide can be obtained. The analysis shows that different metal oxides exhibit their own advantages when intervening in different reaction steps, and there is no one oxide that is optimal in all reactions. Al2O3 exhibits the strongest intervention effect in the chain growth reactions R2 and R3, and ranks second in the R7 reaction, proving that it is the core component with the best comprehensive performance and is indispensable in the formulation system. NiO, ZnO, CuO, CeO2 and SrO, etc., show extremely excellent inhibition potential in specific reaction steps. For example, NiO ranks first in the R7 reaction, and ZnO ranks first in the R1 reaction. This series of calculation results shows that by compounding a variety of oxides with different advantages, a more comprehensive inhibition of the hydrogen explosion chain reaction can be achieved.

[0094] S5: Screening and obtaining the component formula of the composite powder explosion suppressant according to the result of step S4.

[0095] Specifically, step S5 includes the following steps:

[0096] S51: obtaining a candidate powder with excellent explosion suppression performance according to the ranking result of step S4;

[0097] S52: performing secondary screening from two use dimensions of safety and economy, and finally obtaining a component formula of the composite powder explosion suppressant balancing performance, safety and cost.

[0098] On the basis of the explosion suppression performance evaluation, the metal oxides are further systematically evaluated from two dimensions of safety and economy in the embodiment to determine the optimal explosion suppression component. The safety evaluation mainly investigates the toxicity, chemical stability, environmental friendliness and operation safety of the material; and the economy evaluation mainly focuses on the raw material cost, preparation process and feasibility of large-scale production.

[0099] It is found that although the alkali metal oxides Na2O and K2O show inhibition effect on some elementary reactions, they are extremely hygroscopic and can react violently with water to release heat, which has potential safety hazards in storage and use. Among the transition metal oxides, NiO is not suitable as an explosion suppressant component due to its strong toxicity and carcinogenicity; CuO and ZnO have relatively low toxicity and stable chemical properties, but their raw material prices are high, and the production process is relatively complex, which is not conducive to large-scale industrial application. SnO2 and ZrO2 have good chemical stability, but their raw material prices are high, which limits their engineering application. SrO has strong hygroscopicity, and special protection is required during preparation, storage and use, which increases the cost of engineering application.

[0100] In contrast, Al2O3, SiO2, MgO and CeO2 have significant advantages in safety and economy. Al2O3 and SiO2 are ideal explosion suppression components due to their excellent chemical stability, non-toxicity and environmental friendliness, and their raw materials are widely available, the preparation process is mature, and the production cost is controllable. MgO not only has good environmental compatibility and use safety, but also has low price and abundant raw material sources, which provides a guarantee for large-scale application. Although CeO2 has a relatively high price, its significant explosion suppression performance and small amount of use make it an indispensable functional enhancement component.

[0101] Based on the above comprehensive evaluation results, the component formula of the composite powder explosion suppressant, i.e. Al2O3, SiO2, MgO and CeO2, is obtained.

[0102] In order to obtain the specific amount of the above component formula, the inventors further carried out orthogonal test in a 20L spherical explosion device. By continuously adjusting the ratio of each component, taking the explosion suppression efficiency (peak overpressure reduction rate, overpressure rise rate reduction rate) as the evaluation index, the formula range with the best synergistic effect of each component and the economic cost advantage was finally determined, that is, the formula system taking Al2O3 (20-25 parts), SiO2 (20-30 parts), MgO (10-20 parts) and CeO2 (1-3 parts) as the main explosion suppression components.

[0103] In order to further enhance the explosion suppression effect, the application adds 10-15 parts of potassium bicarbonate, 10-15 parts of sodium bicarbonate, 3-8 parts of white carbon black and 2-6 parts of talc powder on the basis of the above raw materials.

[0104] Example 2

[0105] The embodiment provides a modified composite powder explosion suppressant. The preparation method is as follows:

[0106] S01: The raw materials are weighed as follows: 20 parts of alumina, 20 parts of magnesium oxide, 20 parts of silicon dioxide, 2 parts of cerium oxide, 15 parts of potassium bicarbonate, 15 parts of sodium bicarbonate, 3 parts of fumed hydrophobic white carbon black and 5 parts of talc powder.

[0107] S03: The dried raw materials are put into a planetary ball mill, the ball-to-material ratio is set to 8:1, the ball milling speed is 400r / min, and the ball milling time is 3h.

[0108] S04: The composite powder after ball milling is placed in a stirrer, 1% of methyl hydrogen silicone oil is added according to the mass of the composite powder, the stirring speed is 300r / min, and the stirring time is 45min.

[0109] S05: The modified composite powder is dried at 60℃ for 12h.

[0110] S06: Finally, the ultrafine modified composite powder explosion suppressant with a particle size of 90% less than 5μm is obtained through 3000 mesh screen.

[0111] "Ultrafine" is one of the key physical properties to achieve efficient explosion suppression. For hydrogen, which has an extremely fast explosion reaction speed, the explosion suppressant must be able to intervene in the reaction chain instantaneously and in a large area. The ultrafine modified composite powder explosion suppressant of the application has the following properties:

[0112] (1) Huge specific surface area: ultrafine powder has a huge specific surface area, which means that under the same mass, it can provide more active sites for capturing H• and OH• and other key free radicals, and can more efficiently absorb the heat generated by explosion.

[0113] (2) Excellent suspension and dispersion: the smaller the particle size, the better the suspension performance of the powder in the air, the easier it is to be driven by the airflow and uniformly dispersed to the entire explosion area, forming an effective explosion suppression "cloud" to achieve global suppression rather than local suppression.

[0114] (3) Faster reaction rate: ultrafine powder can complete the endothermic decomposition (such as bicarbonate) and free radical capture and other chemical explosion suppression processes faster to fully intervene in the extremely fast reaction chain of hydrogen explosion.

[0115] Example 3

[0116] This example provides an ultrafine modified composite powder explosion suppressant, and the preparation method is as follows:

[0117] S01, the mass fraction of each component raw material is taken: 25 parts of alumina, 10 parts of magnesium oxide, 30 parts of silicon dioxide, 1 part of cerium oxide, 10 parts of potassium bicarbonate, 10 parts of sodium bicarbonate, 8 parts of fumed hydrophobic white carbon black, and 6 parts of talc powder.

[0118] S02, the weighed raw materials are placed in a vacuum drying oven and dried at 60°C for 10h for drying treatment.

[0119] S03, the dried raw materials are placed in a planetary ball mill, the ball-to-material ratio is set to 5:1, the ball milling speed is 300r / min, and the ball milling time is 2h for dry compounding.

[0120] S04, the obtained composite powder is subjected to methyl hydrogen silicone oil coating modification treatment, 0.5% of methyl hydrogen silicone oil is added based on the mass of the composite powder, and stirring is carried out in a stirrer at a stirring speed of 200r / min for 30min.

[0121] S05, the modified composite powder is again placed in a vacuum drying oven and dried at 60°C for 12h.

[0122] S06, the dried powder material is sieved through a 3000 mesh sieve to obtain an ultrafine modified composite powder explosion suppressant with a particle size mainly distributed below 5µm.

[0123] Example 4

[0124] This example provides an ultrafine modified composite powder explosion suppressant, and the preparation method is as follows:

[0125] S01, the mass fraction of each component raw material is taken: 22 parts of alumina, 15 parts of magnesium oxide, 25 parts of silicon dioxide, 3 parts of cerium oxide, 12 parts of potassium bicarbonate, 13 parts of sodium bicarbonate, 8 parts of fumed hydrophobic white carbon black, and 2 parts of talc powder.

[0126] S02, the weighed raw materials are placed in a vacuum drying oven and dried at 80°C for 14 h.

[0127] S03, the dried raw materials are placed in a planetary ball mill, the ball-to-material ratio is set to 10:1, the ball milling speed is 500 r / min, and the ball milling time is 3 h, to perform dry compounding.

[0128] S04, the obtained composite powder is subjected to methyl hydrogen silicone oil coating modification treatment, 2% of methyl hydrogen silicone oil is added based on the mass of the composite powder, and stirring is performed in a stirrer at a stirring speed of 400 r / min for 60 min.

[0129] S05, the modified composite powder is again placed in a vacuum drying oven and dried at 80°C for 15 h.

[0130] S06, the dried powder material is sieved through a 3000-mesh sieve, to obtain an ultrafine modified composite powder explosion inhibitor with a particle size mainly distributed below 5 µm.

[0131] Comparative Example

[0132] To prove the superiority of the component ratio range defined in the present application, the present comparative example is set. The preparation method is the same as that of Example 2 except for the formula, and the remaining process parameters (such as drying, ball milling, modification, sieving, etc.) are the same.

[0133] The mass parts of the comparative example are: 5 parts of alumina, 5 parts of magnesium oxide, 60 parts of silicon dioxide, 5 parts of cerium oxide, 5 parts of potassium bicarbonate, 5 parts of sodium bicarbonate, 5 parts of fumed hydrophobic white carbon black, and 10 parts of talc.

[0134] Explosion suppression performance test

[0135] To verify the actual performance of the composite powder explosion inhibitor described in the present application, the explosion suppression performance of the explosion inhibitor powders prepared in Example 2, Example 3 and Example 4 was tested in a 20L standard spherical explosion test device. The test conditions are as follows: a 30% concentration of hydrogen-air mixture is filled into the device, and a 10J energy pulse ignition device is used for ignition at normal temperature and pressure. Each group of experiments adds 10g of explosion inhibitor powder, and a blank control group without adding any explosion inhibitor is set. The test results are shown in Figure 2 and Figure 3 .

[0136] Figure 2 The explosion overpressure-time history curve under the action of different explosion inhibitors. As can be seen from the blank group (red line in the figure) without adding explosion inhibitor, when the 30% hydrogen-air mixture explodes, the peak overpressure (Pmax) is 0.8MPa, and the time to peak overpressure (tP) is 0.5s. ) reached 0.7257 MPa. After adding 10 g of the explosion suppressant prepared in Example 2, Example 3 and Example 4 respectively, the explosion peak overpressure was significantly suppressed, and reduced to 0.5382 MPa (light blue line in the figure), 0.5292 MPa (green line in the figure) and 0.5182 MPa (dark blue line in the figure) respectively. It was calculated that the explosion suppression efficiency (referring to the reduction amplitude of the peak overpressure) of the three examples reached 25.8%, 27.1% and 28.6% respectively.

[0137] Figure 3 The change of the explosion overpressure rising rate (dP / dt) ) is shown. The peak overpressure rising rate of the blank group reached 178.18 MPa / s, reflecting the intensity of hydrogen explosion. After adding the explosion suppressants of Example 2, Example 3 and Example 4, the value was effectively weakened, and reduced to 152.26 MPa / s, 148.67 MPa / s and 143.81 MPa / s respectively. The corresponding peak overpressure rising rate reduction amplitude reached 14.5%, 16.6% and 19.3% respectively.

[0138] To further verify the advantage of the component ratio defined in the present application, the explosion suppression performance of the explosion suppressant powder prepared in Example 2 and the powder of the comparative example was compared under the same conditions. As shown in Figure 4 , when no explosion suppressant was added, the explosion peak overpressure of 30% hydrogen-air mixture reached 0.7257 MPa, and the peak overpressure rising rate reached 178.18 MPa / s, showing extremely strong destructive power. After adding 10 g of the powder of Example 2 of the present application, the explosion peak overpressure was significantly suppressed to 0.5382 MPa, and the explosion suppression efficiency reached 25.8%; while after adding 10 g of the powder of the comparative example, the peak overpressure was only reduced to 0.6621 MPa, and the explosion suppression efficiency was only 8.8%. Similarly, as shown in Figure 5As shown, the powder of Example 2 effectively reduces the overpressure rising rate to 152.26 MPa / s, with a decrease of 14.5% in terms of inhibiting the explosion development speed; while the overpressure rising rate under the action of the comparative example powder is 165.68 MPa / s, with a decrease of only about 7.0%. This shows that, from the perspective of reducing the final strength of the explosion (peak overpressure) or slowing down the progress of the explosion reaction (overpressure rising rate), the effect of Example 2 of the present application is better than that of the comparative example. This comparison strongly proves that the component ratio range determined by theoretical calculation and experimental optimization of the present application is the key to achieving efficient explosion suppression, and is not a simple combination that is obvious, and has significant creativity. These experimental data strongly prove that the technical solution proposed in the present application has universal effectiveness. Examples 2, 3 and 4, as different formula combinations within the scope of the claims of the present application, all exhibit excellent explosion suppression performance, which directly confirms the scientificity of the component ratio range of the present application. The reduction of peak overpressure means that the final destructive power of the explosion is effectively weakened, which is attributed to the high-efficiency heat absorption effect and the chemical interruption effect on the explosion chain reaction of the powder. At the same time, the slowing down of the overpressure rising rate indicates that the intensity of the explosion progress is controlled, which has crucial practical significance for protecting pressure-bearing equipment and gaining valuable time for safety measures.

[0139] Therefore, the composite powder explosion suppressant designed and prepared based on quantum chemical calculation of the present application can produce obvious inhibition effect on severe hydrogen explosion under a small amount of addition, and can be used as an efficient and economical active safety protection measure in the hydrogen energy industry chain. In order to build a more comprehensive safety system, it is suggested to deploy the explosion suppressant together with hydrogen leakage detection, anti-static, forced ventilation and other preventive measures.

[0140] The action mechanism of the composite powder explosion suppressant based on quantum calculation of the present embodiment is as follows:

[0141] (1) The heat barrier layer formed by the suspended Al2O3, MgO, SiO2, CeO2, KHCO3 and NaHCO3 significantly reduces the heat radiation transfer efficiency from the combustion zone to the unburned zone, and effectively blocks the heat conduction.

[0142] (2) Al2O3, MgO, SiO2 and CeO2 capture H• and OH• free radicals in the hydrogen explosion reaction through targeted bonding, inhibit their participation in chain transfer reactions, and thus block the continuous progress of the hydrogen explosion reaction.

[0143] (3) KHCO3 and NaHCO3 decompose upon contact with the hydrogen explosion flame, and this endothermic process can significantly reduce the temperature of the explosion area, thereby inhibiting the reaction rate of the explosion.

[0144] (4) The decomposition products of KHCO3 and NaHCO3, CO2 and H2O, have a double explosion suppression effect: CO2, as an inert gas, dilutes the O2 concentration in the explosion zone, resulting in a flame suffocation effect; H2O not only has a significant endothermic effect, but also can further dilute the O2 concentration after vaporization, strengthening the flame suffocation effect.

[0145] (5) K + , Na + and KO•, NaO•, etc., produced by the decomposition of KHCO3 and NaHCO3, can selectively bind to the key active groups (H•, OH• and O•) that can react with hydrogen gas, effectively interrupting the chain reaction process and significantly reducing the explosion pressure. The key reaction equations are as follows:

[0146] 2NaHCO3→Na2CO3+CO2+H2O;

[0147] Na2CO3→Na2O+CO2;

[0148] Na2O+H2O→2NaOH;

[0149] NaOH+OH→NaO+H2O;

[0150] NaOH+H→Na+H2O;

[0151] Na+OH+M→NaOH+M;

[0152] NaO+O→Na+O2;

[0153] NaO+H→Na+OH;

[0154] 2KHCO3→K2CO3+CO2+H2O;

[0155] K2CO3→K2O+CO2;

[0156] K2O+H2O→2KOH;

[0157] KOH+OH→KO+H2O;

[0158] KO+O→K+O2;

[0159] KOH+H→K+H2O;

[0160] K+OH+M→KOH+M;

[0161] K+O2+M→KO2+M;

[0162] KO2+H→KOH+O;

[0163] KO2+OH→KOH+O2.

[0164] The present application not only realizes multiple inhibition of key elementary reactions of hydrogen combustion, but also achieves optimal balance in safety and economy, and has significant engineering application value.

[0165] Those skilled in the art will easily understand that the above description is only a preferred embodiment of the present application, and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0166] The part of the present application specification not described in detail belongs to the known technology in the art, and the above examples are only provided for the purpose of describing the present application, and are not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims. Various equivalent replacements and modifications made without departing from the spirit and principle of the present application shall be included in the scope of the present application.

Claims

1. A design method of a composite powder explosion suppression agent, characterized by, It comprises the following steps: S1: structure optimization and frequency analysis of key elementary reactions in the application field of the composite powder explosion inhibitor to obtain a correct optimized configuration; S2: single-point energy calculation of the correct optimized configuration to obtain the energy difference of the key elementary reactions; S3: calculation of the effect of the powder on the total energy of the reaction system under the correct optimized configuration to obtain the energy difference of the key elementary reactions in the presence of the powder; S4: comparison of the results of step S3 and step S2 to obtain the ranking of the explosion suppression performance of the powder; S5: screening of the component formula of the composite powder explosion inhibitor according to the results of step S4.

2. The design method of the composite powder explosion suppressant according to claim 1, wherein The S1: structure optimization and frequency analysis of key elementary reactions in the application field of the composite powder explosion inhibitor specifically comprises the following steps: S11: structure optimization of key elementary reactions in the application field of the composite powder explosion inhibitor, wherein the structure optimization is specifically adjusting the geometry of the system until the total energy of the system reaches a local minimum value to obtain an optimized configuration; S12: frequency analysis of the optimized configuration to obtain a correct optimized configuration.

3. The design method of the composite powder explosion suppressant according to claim 1, wherein The S3: calculation of the effect of the powder on the total energy of the reaction system specifically comprises the following steps: S31: calculation of the single-point energy of the powder in isolation and the single-point energy of the powder in each state in the key elementary reactions; S32: obtaining the reaction path energy difference in the presence of the powder according to the single-point energy calculated in step S31.

4. The design method of a composite powder explosion suppression agent according to claim 1, wherein The S5: screening of the component formula of the composite powder explosion inhibitor according to the results of step S4 specifically comprises the following steps: S51: obtaining candidate powders with excellent explosion suppression performance according to the ranking results of step S4; S52: secondary screening from the two use dimensions of safety and economy to finally obtain a component formula of the composite powder explosion inhibitor that balances performance, safety, and cost.

5. The design method of the composite powder explosion suppressant according to claim 1, wherein The application field of the composite powder explosion inhibitor is to suppress hydrogen explosion.

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