Composite dry water explosion suppressant for suppressing explosion of organic dust and preparation method of composite dry water explosion suppressant

Abstract

The invention relates to the technical field of explosion suppressants, and provides a composite dry water explosion suppressant for suppressing organic dust explosion and a preparation method thereof.The composite dry water explosion suppressant is prepared from, by weight, 100 m l of deionized water, 10 g of hydrophobic fumed silica, 0.772 g of ammonium polyphosphate, 1.487 g of cobalt nitrate hexahydrate, 1.602 g of dimethylimidazole and 200 ml of methyl alcohol. Wherein the particle sizes of the hydrophobic fumed silica, the ammonium polyphosphate, the cobalt nitrate hexahydrate and the dimethylimidazole are smaller than 5 microns. The composite dry water explosion suppressant provided by the invention has the advantages of good explosion suppression and explosion prevention performance, small dosage and high explosion suppression efficiency, can effectively slow down the overall combustion speed and explosion speed, achieves the effect of greatly increasing the explosion reaction propagation resistance, and also can form a flame-retardant and explosion-proof effect at the initial stage of matrix combustion.

Description

Technical Field

[0001] The present invention relates to the technical field of explosion suppressants, and more specifically, to a composite dry water explosion suppressant for suppressing organic dust explosion and a preparation method thereof. Background Art

[0002] In industrial production, organic dust explosion is a serious safety issue. Organic dust, such as PMMA dust, biomass dust (poplar sawdust and peanut shell dust), coal dust, etc., can easily cause explosion under certain conditions.

[0003] As an effective means of controlling dust explosions, explosion suppression technology can reduce the explosion scale in the early stage of the explosion, and even fundamentally curb the occurrence of the explosion. The core of dust explosion suppression technology is to research and develop explosion suppressants with better explosion suppression performance. Therefore, actively exploring the prevention and control theory of organic dust explosions and formulating reasonable and effective explosion prevention measures are crucial to the production safety of enterprises.

[0004] At present, the research on powder explosion suppression materials focuses on the explosion suppression of a single substance, such as rock powder, CaCO3, Na2CO3, Al(OH)3, etc. Studies have shown that composite powder explosion suppressants formed by a combination of multiple substances can exert the coupled explosion suppression effect of multiple substances during the explosion suppression process, and their explosion suppression effect is better. The development of composite powder explosion suppressants using industrial solid waste can better solve the problem of waste resource recycling, and at the same time bring new solutions to the safety field of industrial dust explosion suppression;

[0005] Based on this, the present application proposes a composite dry water explosion suppressant for suppressing organic dust explosion and a preparation method thereof. Summary of the invention

[0006] The purpose of the present invention is to provide a composite dry water explosion suppressant for suppressing organic dust explosion and a preparation method thereof, thereby enhancing the performance of dust explosion suppression and explosion prevention.

[0007] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0008] In one aspect, the present invention provides a composite dry water explosion suppressant for suppressing organic dust explosions. The composite dry water explosion suppressant comprises raw materials in parts by weight:

[0009] 100 ml of deionized water, 10 g of hydrophobic fumed silica, 0.772 g of ammonium polyphosphate, 1.487 g of cobalt nitrate hexahydrate, 1.602 g of dimethylimidazole, and 200 ml of methanol, wherein the particle sizes of the hydrophobic fumed silica, ammonium polyphosphate, cobalt nitrate hexahydrate, and dimethylimidazole are all less than 5 μm.

[0010] On the other hand, the present invention provides a method for preparing a composite dry water explosion suppressant, and the specific preparation steps are as follows:

[0011] Raw material preparation stage: First, accurately weigh 1.487 g of cobalt nitrate hexahydrate, 1.602 g of dimethylimidazole and 0.772 g of ammonium polyphosphate, and place them separately for later use;

[0012] Solvent preparation stage: Then, accurately measure 50ml, 50ml, and 100ml of methanol solution respectively according to the volume ratio of 1:1:2, and set them aside for later use;

[0013] Mixing reaction stage: weighed cobalt nitrate hexahydrate, dimethyl imidazole and ammonium polyphosphate are added to the pre-measured methanol solution in sequence, and stirred for 2 hours respectively to obtain solution A, solution B and solution C; after the stirring is completed, solution A is first poured into solution B and stirred continuously, and then mixed with solution C, and stirred continuously for 2 hours to ensure sufficient mixing;

[0014] Filtration and drying stage: the mixed raw materials are filtered and washed through a filtration device to remove impurities; the washed solids are placed in a vacuum drying oven and dried at 60°C for 24 hours; after drying, the solids are taken out and ground for subsequent use, and the obtained solid powder is a ZIF-67 and APP composite material APP-Co-ZIF;

[0015] Preparation stage of composite dry water explosion suppressant: weigh 10g of hydrophobic fumed silica and 100ml of deionized water; weigh 2g of ground powder and pour it into deionized water, and add hydrophobic fumed silica; use a high-speed stirrer to adjust the speed to 6000r / min and stir for 90s. After stirring, the required composite dry water explosion suppressant can be obtained.

[0016] Beneficial effects of the present invention:

[0017] The composite dry water explosion suppressant provided by the present invention can block the contact between coal powder and oxygen, absorb heat through the joint action, dilute the combustible gas, consume free radicals and form a carbon layer covering the surface of the coal powder, thereby preventing contact with the outside world, so that the coal powder explosion cannot continue, and finally achieve the effect of explosion suppression and explosion prevention;

[0018] The composite dry water explosion suppressant provided by the present invention can reduce the ambient temperature in real time during coal seam combustion and explosion through the endothermic decomposition of APP-Co-ZIF powder, thereby achieving the effect of heat release during pyrolysis and gasification of competing coal, and can effectively reduce the overall combustion speed and explosion speed, thereby achieving the effect of significantly increasing the propagation resistance of the explosion reaction;

[0019] The composite dry water explosion suppressant provided by the present invention can achieve a safety protection effect in the early stage of combustion, utilizes APP-Co-ZIF powder to decompose into a non-combustible carbon layer under heat and coats the surface of the substrate, and promotes the rapid formation of residual carbon, thereby forming a flame retardant and explosion-proof effect in the early stage of substrate combustion. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to the examples. However, it should be understood that the following examples are only illustrative of the embodiments of the present invention, and are not intended to limit the scope of the present invention.

[0021] The specific explosion suppression mechanism of the composite dry water explosion suppressant for suppressing organic dust explosion provided by the present invention is:

[0022] Taking coal powder as an example, first of all, dry water explosion suppressant is a new type of capsule-shaped explosion suppressant containing a soluble powder explosion suppressant aqueous solution wrapped by hydrophobic fumed silica, and its water content is as high as 90%. Therefore, its structure will be destroyed in high-temperature environments such as explosion or thermal decomposition, and water molecules will evaporate and absorb a large amount of heat, effectively reducing the temperature of the reaction system, thereby reducing coal powder explosion; in addition, silica, as an inert material, covers the surface of coal powder, which can block the contact between coal powder and oxygen, thereby playing the role of suppressing coal powder explosion.

[0023] ZIF-67 and composite material APP-Co-ZIF have a large specific surface area. The adsorption capacity of ZIF-67 on the surface of APP-Co-ZIF can absorb heat and gas in the system, reducing the risk of combustion and explosion in the system. During the combustion and explosion of coal dust, APP-Co-ZIF powder decomposes by endothermic absorption, which can reduce the immediate temperature of the surrounding environment. This endothermic behavior competes with the heat released by coal during pyrolysis and gasification, effectively slowing down the overall combustion and explosion rate in the spherical combustion chamber. At the same time, the thermal decomposition of APP-Co-ZIF powder produces NH3 and water vapor, which can dilute the oxygen in the explosion system and the combustible gas produced by coal pyrolysis. Thereby, the continuous combustion and explosion reaction in the combustion chamber are severely hindered, making it more difficult to propagate.

[0024] APP-Co-ZIF is decomposed into polyphosphoric acid, metaphosphoric acid and other phosphoric acid derivatives under heat. These phosphoric acid derivatives have the function of catalyzing the cross-linking of polymers into carbon, dehydrating and carbonizing the surface of the matrix, forming a non-combustible carbon layer covering the surface of the matrix, acting as a physical barrier, delaying the exchange of combustible substances and the conduction of heat energy, and reducing the decomposition rate of the internal matrix; in addition, due to the presence of cobalt ions, Co2+ in APP-Co-ZIF promotes the rapid generation of P-OH, so that structures such as PO-Co-OC and POC are formed earlier, thereby promoting the rapid formation of residual carbon, thereby playing a safety protection role in the early stage of combustion; with the increase of temperature and the release of H2O and NH3, more POC and phosphorylated cross-linked structures and CoOx are generated on the carbon layer, and gradually a dense and stable carbon layer composed of POC, C=C, CN, CoOx, etc. is formed, which achieves a good barrier effect during the combustion process.

[0025] Furthermore, the phosphate derivatives obtained by decomposition during the combustion of APP-Co-ZIF will undergo a disproportionation reaction to generate HPO·, PO2· and PO· free radicals. These free radicals can capture the H· and OH· free radicals produced by the polymer chain reaction, play a quenching role, and reduce heat release; therefore, the explosion suppression mechanism of the composite explosion suppressant on coal powder combines the effects of dry water and APP-Co-ZIF itself with the structural characteristics of imidazole metal organic framework materials and the synergistic effects brought by cobalt ions, including physical and chemical effects, which absorb heat through joint action, dilute combustible gases, consume free radicals, and form a carbon layer covering the surface of coal powder to prevent contact with the outside world, ultimately achieving the effect of explosion suppression.

[0026] In the above explosion suppression mechanism, the coal powder explosion cannot continue through the comprehensive suppression effect of various materials, and finally the purpose of suppressing the coal powder explosion is achieved, so that it has excellent explosion suppression and explosion proof performance in the explosive coal powder explosion environment.

[0027] In the above textual description of the explosion suppression mechanism of the composite dry water explosion suppressant, the main chemical reaction equations involved are as follows:

[0028] NH4+OH→OH+H2O

[0029] NH3+H+→NH2+H2

[0030] NH2+O2→NHO+OH

[0031] NH3+OH→NH2+H2O

[0032] H3PO4→HPO3+PO+HPO

[0033] PO+H→HPO

[0034] HPO+H→H2+PO

[0035] PO+OH→HPO+O

[0036] PO+OH+H2→HPO+H2O

[0037] PO+Co→POCo

[0038] CO + O → CoO

[0039] Experiment 1

[0040] The raw material formula of the explosion suppressant for suppressing coal powder explosion is: 10g hydrophobic fumed silica and 100ml deionized water.

[0041] Preparation method: hydrophobic fumed silica is mixed with deionized water, and stirred for 90 seconds in a high-speed disperser at a speed of 6000 r / min to obtain a common dry water explosion suppressant;

[0042] The minimum amount of ordinary dry water explosion suppressant required to suppress coal dust explosion was determined using a 20L explosion ball test system. The experimental results are shown in Table 1.

[0043] Experiment 2

[0044] The raw material formula of APP composite dry water explosion suppressant for suppressing coal powder explosion is: hydrophobic fumed silica, deionized water, ammonium polyphosphate;

[0045] Preparation method: Weigh 2g of ammonium polyphosphate, add 100ml of deionized water and stir evenly, then add 10g of silicon dioxide, and then mix in a high-speed disperser with a rotation speed of 6000r / min and stir for 90s to obtain APP composite dry water explosion suppressant;

[0046] The minimum amount of explosion suppressant for suppressing organic dust explosion required to suppress coal dust explosion was determined using a 20L explosion ball test system. The experimental results are shown in Table 1.

[0047] Experiment 3

[0048] A 20L explosion ball experimental system was used to test a composite dry water explosion suppressant for suppressing organic dust explosion provided by the present invention;

[0049] The minimum amount of the composite dry water explosion suppressant for suppressing organic dust explosion required to suppress coal dust explosion was determined using a 20L explosion ball test system. The experimental results are shown in Table 1.

[0050]

[0051] Table 1

[0052] As can be seen from Table 1 above, from Experiment 1 to Experiment 3, the amount of composite dry water explosion suppressant required to completely suppress the coal powder explosion is the lowest.

[0053] It can be understood that the above-mentioned technical solution, a composite dry water explosion suppressant for suppressing organic dust explosions, has the advantages of good explosion suppression and explosion protection performance, small dosage and high explosion suppression efficiency. Compared with the existing technology, it has more outstanding advantages and provides a new idea for suppressing organic dust explosions.

[0054] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A composite dry water explosion suppressant for suppressing organic dust explosion, characterized in that: The composite dry water explosion suppressant includes the following raw materials in parts by weight: 100 parts of deionized water, 10 parts of hydrophobic fumed silica, 0.772 parts of ammonium polyphosphate, 1.487 parts of cobalt nitrate hexahydrate, 1.602 parts of dimethylimidazole, and 200 parts of methanol.

2. The composite dry water explosion suppressant for suppressing organic dust explosion according to claim 1, characterized in that: The proportions of raw materials in the composite dry water explosion suppressant are: 31.86% deionized water, 3.19% hydrophobic fumed silica, 0.25% ammonium polyphosphate, 0.47% cobalt nitrate hexahydrate, 0.51% dimethylimidazole, and 63.72% methanol.

3. The composite dry water explosion suppressant for suppressing organic dust explosion according to claim 1, characterized in that: The particle sizes of hydrophobic fumed silica, ammonium polyphosphate, cobalt nitrate hexahydrate and dimethylimidazole in the composite dry water explosion suppressant raw materials are all less than 5 μm.

4. A method for preparing an explosion suppressant, for preparing the composite dry water explosion suppressant as claimed in any one of claims 1 to 3, characterized in that: The specific preparation steps are as follows: S1: In the raw material preparation stage, 1.487 g of cobalt nitrate hexahydrate, 1.602 g of dimethylimidazole and 0.772 g of ammonium polyphosphate were accurately weighed and placed separately for later use; S2: In the solvent preparation stage, 50 ml, 50 ml, and 100 ml of methanol solution are accurately measured respectively according to a volume ratio of 1:1:2, and are set aside for later use; S3: In the mixing reaction stage, the weighed cobalt nitrate hexahydrate, dimethyl imidazole and ammonium polyphosphate are added to the pre-measured 50 ml, 50 ml and 100 ml methanol solutions in sequence, and stirred for 2 hours respectively to obtain solution A, solution B and solution C; after the stirring is completed, solution A is first poured into solution B and stirred continuously, and then mixed with solution C, and stirred continuously for 2 hours to make them fully mixed; S4: Filtration and drying stage, the raw material is filtered and washed to remove impurities; the washed solid is placed in a vacuum drying oven and dried at 60°C for 24 hours; after drying, the solid is taken out and ground to obtain a powder for subsequent use, and the obtained solid powder is a ZIF-67 and APP composite material APP-Co-ZIF; S5: In the preparation stage of the composite dry water explosion suppressant, 10 g of hydrophobic fumed silica is weighed, and 100 ml of deionized water is measured, 2 g of powder is weighed and poured into the deionized water, and the hydrophobic fumed silica is added, and the mixture is stirred and mixed using a high-speed stirrer to obtain the composite dry water explosion suppressant.

5. The method for preparing an explosion suppressant according to claim 4, characterized in that: The raw materials in step S4 are the raw materials finally mixed uniformly in S3.

6. The method for preparing an explosion suppressant according to claim 4, characterized in that: The powder in step S5 is the powder obtained by grinding in step S4.

7. The method for preparing an explosion suppressant according to claim 4, characterized in that: The stirring speed in step S5 is 6000 r / min, and the stirring operation lasts for 90 s.

8. The method for preparing an explosion suppressant according to claim 4, characterized in that: Step S5 also includes the step of determining the composite dry water explosion suppressant with the best fluidity under different speeds and times of the high-speed agitator.

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