Corrosion resistant coating for ammonia decomposition, method of making, and ammonia decomposition reactor

Abstract

The application also discloses a corrosion-resistant coating for ammonia decomposition, a preparation method and an ammonia decomposition reactor, which comprises a high-temperature-resistant component, the high-temperature-resistant component comprises a silicone resin, a filler, a solvent and an additive, the silicone resin accounts for 50-60% of the high-temperature-resistant component, the filler accounts for 20-30% of the high-temperature-resistant component, and the rest is the solvent and the additive; a metal component, the metal component comprises a nickel element and a niobium element, the content of the nickel element in the metal component is greater than that of the niobium element; a ceramic component, the ceramic component comprises a silicon element, a carbon element and aluminum oxide, the mass ratio between the silicon element and the carbon element is 1:1, and the aluminum oxide accounts for 60-80% of the ceramic component; the content of the high-temperature-resistant component is 35-55%, the content of the high-temperature-resistant component is greater than that of the metal component, and the content of the high-temperature-resistant component is greater than that of the ceramic component. The corrosion-resistant coating for ammonia decomposition has good ammonia gas corrosion resistance and heat resistance, and also has good thermal conductivity, which is beneficial to the thermal decomposition of ammonia gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical coating preparation, and particularly relates to a corrosion-resistant coating for ammonia decomposition, a preparation method and an ammonia decomposition reactor. BACKGROUND

[0002] Ammonia is not only an important inorganic chemical product, but also has unique advantages as a hydrogen carrier. Ammonia is easy to liquefy, has a pungent odor, is non-flammable and non-toxic at low concentrations, has a high hydrogen storage density, and has mature production and storage and transportation technologies. In addition, there is no carbon emission in the hydrogen production process, so ammonia is a high-efficiency, clean and safe hydrogen storage carrier. The preparation of hydrogen by decomposing ammonia is also one of the feasible and effective hydrogen production technology routes. The ammonia decomposition reactor is one of the equipment for processing high-concentration ammonia. However, such reactors often face a problem: corrosion. Due to the high temperature, high pressure and highly corrosive environment inside the reactor, the corrosion problem is particularly serious. This not only shortens the service life of the reactor, but also may pose a threat to the health of the operators. Therefore, it is urgent to develop a coating material that can resist such corrosion and high temperature.

[0003] Chinese patent CN104878378A discloses a high-temperature-resistant coating for a metal surface and a preparation method thereof, wherein the coating successively contains carbon, magnesium, chromium, vanadium, nickel, calcium, niobium, molybdenum, barium, tungsten, titanium, aluminum, lanthanum, dysprosium, neodymium, promethium, europium and dysprosium, and the remaining element is iron. The high-temperature-resistant coating is sprayed with an anti-corrosion paint on the surface, thereby improving the corrosion resistance. The high-temperature-resistant coating has high strength and strong corrosion resistance and high-temperature resistance. However, the high-temperature-resistant coating has limited heat resistance and poor thermal conductivity, and is not suitable for the working environment of continuous heating in the ammonia decomposition process. In addition, the high-temperature-resistant coating has high manufacturing cost and complex process conditions due to the introduction of rare earth metals. SUMMARY

[0004] In view of the defects of the prior art, such as the limited heat resistance and poor thermal conductivity of the high-temperature-resistant and corrosion-resistant coating, the high manufacturing cost and complex process conditions, and the inability to be applied to the high-temperature and strong-corrosion application environment of ammonia decomposition, the present application provides a corrosion-resistant coating for ammonia decomposition, which has good heat resistance and thermal conductivity, can meet the requirements of high-temperature resistance and corrosion resistance in the ammonia decomposition environment, has low manufacturing cost and simple process conditions, and a preparation method thereof.

[0005] The technical scheme adopted by the present application to solve its technical problems is: a kind of corrosion-resistant coating for ammonia decomposition, which is composed of high-temperature-resistant component, metal component and ceramic component;The high-temperature-resistant component includes silicone resin, filler, solvent and additive, the silicone resin accounts for 50-60% of the high-temperature-resistant component, the filler accounts for 20-30% of the high-temperature-resistant component, and the rest is solvent and additive;The metal component includes nickel element and niobium element, and the content of nickel element in the metal component is greater than that of niobium element;The ceramic component includes silicon element, carbon element and alumina, and the mass ratio between silicon element and carbon element is 1:1, and the alumina accounts for 60-80% of the ceramic component;The content of high-temperature-resistant component is 35-55%, the content of high-temperature-resistant component is greater than the content of the metal component, and the content of high-temperature-resistant component is greater than the content of the ceramic component.

[0006] Further, the silicone resin in the high-temperature-resistant component is prepared by the following method, step one: placing a mixture composed of multiple chlorosilanes in an acidic environment below 25℃, the chlorosilane mixture and water successively undergo hydrolysis reaction, generating multiple silicols containing methyl or phenyl groups, and the multiple silicols containing methyl or phenyl groups continue to undergo condensation reaction, generating silicol polymer containing multiple methyl and multiple phenyl groups;Step two: washing the obtained silicol polymer containing methyl and phenyl groups with water, and heating the washed silicol polymer to obtain an intermediate;Step three: mixing the intermediate and resin mixture and stirring to obtain silicone resin gel, and further stirring the obtained silicone resin gel by adding water to obtain silicone resin sol.

[0007] Further, in step one, the chlorosilane mixture is composed of methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane and diphenyldichlorosilane.

[0008] Further, in step two, the obtained silicol polymer containing methyl and phenyl groups is washed with water, and heated at a temperature of 100-150℃ after washing;In step three, the resin mixture is a mixture of epoxy resin and high-temperature-resistant resin or high-temperature-resistant modifier.

[0009] Further, the solvent is xylene, and the additive is dispersant, adhesion agent, anti-settling thixotropic agent or defoaming agent;The filler includes titanium white powder, talc powder, glass powder and heat stabilizer.

[0010] Further, the mass percentage of niobium element and nickel element in the metal component ranges from 1:3 to 1:8, and the particle size of the metal component is 10-25um.

[0011] Further, the ceramic component contains silicon carbide and alumina, and the mass percentage of silicon carbide and alumina ranges from 1:4 to 2:3, and the particle size of the ceramic component is 15-45um.

[0012] The application also discloses a preparation method for preparing the corrosion-resistant coating for ammonia decomposition.

[0013] Step one: mixing the high-temperature-resistant component, the metal component and the ceramic component, wherein the high-temperature-resistant component accounts for 35-55% of the total mass after mixing, the metal component accounts for 25-35% of the total mass after mixing, and the rest is the ceramic component;

[0014] Step two: stirring the mixed high-temperature-resistant component, the metal component and the ceramic component at a rotating speed of 100-150 r / min for 5-8 minutes;

[0015] Step three: continuing to stir the mixed high-temperature-resistant component, the metal component and the ceramic component after stirring in step two at a rotating speed of 700-800 r / min for 8-10 minutes;

[0016] Step four: stirring the mixed high-temperature-resistant component, the metal component and the ceramic component after stirring in step three at a rotating speed of 500-600 r / min for 4-9 minutes to obtain a basic composite coating;

[0017] Step five: adding water to the basic composite coating to obtain the corrosion-resistant coating for ammonia decomposition.

[0018] The application also discloses an ammonia decomposition reactor containing the corrosion-resistant coating for ammonia decomposition.

[0019] The inner surface of the ammonia decomposition reactor is covered with the corrosion-resistant coating for ammonia decomposition, and the thickness of the corrosion-resistant coating for ammonia decomposition is equal to each other.

[0020] Further, the thickness of the corrosion-resistant coating for ammonia decomposition on the inner surface of the ammonia decomposition reactor ranges from 15 to 25 um.

[0021] The corrosion-resistant coating for ammonia decomposition has the advantages that the corrosion-resistant coating for ammonia decomposition simultaneously has good ammonia corrosion resistance and heat resistance during ammonia decomposition, can protect the ammonia decomposition reactor in the ammonia flow environment, and reduces the corrosion of ammonia to the ammonia decomposition reactor; meanwhile, the corrosion-resistant coating for ammonia decomposition also has good heat conductivity, can well transfer heat to ammonia during ammonia flow, thereby promoting the thermal decomposition of ammonia, and can also be suitable for long-time heating decomposition of ammonia; the corrosion-resistant coating can prevent ammonia corrosion, has good high-temperature resistance, good heat conductivity and ammonia decomposition promotion effect. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a process flow diagram of the method for preparing the corrosion-resistant coating for ammonia decomposition according to the present invention. Detailed Implementation

[0024] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figure 1 As shown, the corrosion-resistant coating for ammonia decomposition described in this invention is composed of a high-temperature resistant component, a metal component, and a ceramic component:

[0026] The high-temperature resistant component includes silicone resin, filler, solvent and additives, wherein the silicone resin accounts for 50-60% of the high-temperature resistant component, the filler accounts for 20-30% of the high-temperature resistant component, and the remainder is solvent and additives.

[0027] The metal component includes nickel and niobium, with niobium accounting for 12.5% ​​to 25% of the metal component and the remainder being nickel.

[0028] The ceramic component includes silicon, carbon, and alumina, with a mass ratio of silicon to carbon of 1:1, and alumina accounting for 60-80% of the ceramic component.

[0029] The content of the high-temperature-resistant component is 35-55% of the mass of the corrosion-resistant coating for ammonia decomposition, the content of the high-temperature-resistant component is greater than the content of the metal component, and the content of the high-temperature-resistant component is greater than the content of the ceramic component. By using the high-temperature-resistant component containing silicone resin, filler, solvent and auxiliary, the corrosion-resistant coating for ammonia decomposition reactor can be applied to the high-temperature environment required for ammonia decomposition, and also has good heat preservation effect to meet the heat requirement of ammonia heating; after the high-temperature-resistant component is fully and uniformly mixed with the metal component and the ceramic component, the corrosion-resistant coating for ammonia decomposition reactor can meet the requirement of ammonia heating decomposition, reduce the influence of ammonia corrosion on the ammonia decomposition reactor, improve the service life of the ammonia decomposition reactor, improve the heat transfer efficiency in the ammonia decomposition reactor, and promote the heating decomposition of ammonia.

[0030] The silicone resin in the high-temperature-resistant component is silicone resin sol, which contains intermediates and modified resins with good heat resistance, and the intermediates contain methyl and phenyl groups; after the modified resins are combined with the intermediates, silicone resins with good high-temperature resistance are obtained; specifically, the preparation method of the silicone resin is as follows:

[0031] Step one: mix the mixture composed of multiple chlorosilanes with water in an acidic environment below 25℃, the mixture composed of multiple chlorosilanes and water undergoes hydrolysis reaction to generate multiple silicols containing methyl or phenyl groups, and the multiple silicols containing methyl or phenyl groups continue to undergo condensation reaction to generate silicol polymer containing multiple methyl and multiple phenyl groups;

[0032] Step two: wash the obtained silicol polymer containing methyl and phenyl groups with water, and then heat the silicol polymer to remove excess water and residual solvent on the surface of the silicol polymer containing methyl and phenyl groups to obtain intermediates;

[0033] Step three: mix the intermediates and resin mixture and stir to obtain silicone resin gel, and further stir the obtained silicone resin gel by adding water to obtain silicone resin sol.

[0034] In the above step one, the chlorosilane mixture includes methyl compounds and phenyl compounds, specifically, the methyl compounds are methyltrichlorosilane or dimethyldichlorosilane, and the phenyl compounds are phenyltrichlorosilane or diphenyldichlorosilane; the chlorosilane mixture containing methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane or diphenyldichlorosilane is placed in an acidic solution environment below 25℃, such as hydrochloric acid solution, and methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane and diphenyldichlorosilane respectively undergo the following hydrolysis reactions with water:

[0035] CH3SiCl3 + 3H2O → CH3Si(OH)3 + 3HCl + H2O

[0036] CH3SiCl2 + H2O → CH3Si(OH)2Cl + HCl

[0037] PhSiCl3 + 3H2O → PhSi(OH)3 + 3HCl

[0038] Ph2SiCl2 + H2O → Ph2Si(OH)2Cl + HCl

[0039] The generated CH3Si(OH)3 and CH3Si(OH)2Cl continue to undergo condensation reactions with PhSi(OH)3 and Ph2Si(OH)2Cl, respectively, under the same reaction conditions (in an acidic solution environment at 25°C) to obtain silanol polymers containing both methyl and phenyl groups, such as (CH3Si(OH)3)2-(PhSi(OH)3)2 or (CH3Si(OH)2Cl)2-(Ph2Si(OH)2Cl)2; the specific corresponding reaction processes are as follows:

[0040] When the methyl compound is CH3Si(OH)3 and the phenyl compound is PhSi(OH)3, CH3Si(OH)3 undergoes condensation reaction with PhSi(OH)3 to generate a silanol polymer containing both methyl and phenyl groups (CH3Si(OH)3)2-(PhSi(OH)3)2;

[0041] When the methyl compound is CH3Si(OH)3 and the phenyl compound is Ph2Si(OH)2Cl, CH3Si(OH)3 undergoes condensation reaction with Ph2Si(OH)2Cl to generate a silanol polymer containing both methyl and phenyl groups (CH3Si(OH)3)2-(PhSi(OH)3)2;

[0042] When the methyl compound is CH3Si(OH)2Cl and the phenyl compound is Ph2Si(OH)2Cl, CH3Si(OH)2Cl undergoes condensation reaction with Ph2Si(OH)2Cl to generate a silanol polymer containing both methyl and phenyl groups (CH3Si(OH)2Cl)2-

[0043] (Ph2Si(OH)2Cl)2;

[0044] When the methyl compound is CH3Si(OH)2Cl and the phenyl compound is PhSi(OH)3, CH3Si(OH)2Cl undergoes condensation reaction with Ph2Si(OH)2Cl to generate a silanol polymer containing both methyl and phenyl groups (CH3Si(OH)2Cl)2-(PhSi(OH)3)2.

[0045] In the above-mentioned step two, the silanol polymer containing methyl and phenyl groups obtained in step one is washed with water to remove the residual hydrochloric acid solution on the surface of the silanol polymer and adjust the pH value of the silanol polymer to neutral, and then the washed silanol polymer containing methyl and phenyl groups is heated and evaporated at a temperature of 100-150°C or above to remove the excess water and hydrochloric acid solvent left in the washing process, and also to prevent the silanol polymer containing methyl and phenyl groups from deteriorating at too high a temperature, affecting the performance of the subsequent high-temperature-resistant components. After evaporation, a silanol polymer with the molecular formula (CH3Si(OH)3)2-(PhSi(OH)3)2 or (CH3Si(OH)2Cl)2-(Ph2Si(OH)2Cl)2 is obtained as an intermediate for subsequent reactions.

[0046] In the above-mentioned step three, the resin mixture mixed with the intermediate obtained in step two is a modified resin mixture with good heat resistance, which is a mixture of epoxy resin and high-temperature-resistant modifier or high-temperature-resistant resin, wherein the high-temperature-resistant resin is polyimide, polyphenyl ether or polysulfone; the high-temperature-resistant modifier is diphenyl ether or phenolic resin; after mixing the modified resin mixture with the intermediate, the mixture of the resin mixture and the intermediate is stirred uniformly, and the uniformly stirred resin mixture and intermediate are further heated to 80-150°C to promote the mutual reaction between the resin mixture and the intermediate. Under the heating conditions, the epoxy groups in the epoxy resin in the resin mixture and the hydroxyl groups in the intermediate undergo ring-opening reaction to obtain silicone resin, and then the silicone resin is further heated to promote the curing of the silicone resin and improve the stability of the silicone resin; finally, water is added to the cured silicone resin and stirred to form silicone resin sol for subsequent further preparation reactions.

[0047] The silicone resin obtained by the above preparation method is mixed with a solvent and an auxiliary agent, wherein the solvent is xylene, and the auxiliary agent is a dispersing agent, an adhesion promoter, a deflocculant or an antifoaming agent; by adding the auxiliary agent, the adhesion of the silicone resin can be improved, and the silicone resin can also be fully and uniformly dispersed in the mixed solution; after the solvent and the auxiliary agent are added to the silicone resin sol, the auxiliary agent and the solvent are stirred at a rotation speed of 100-150 r / min, so that the auxiliary agent, the solvent and the silicone resin are fully dispersed and mixed, and the stirring time is 5-8 minutes; after the auxiliary agent, the solvent and the silicone resin are uniformly dispersed, the filler is added to the dispersed silicone resin; the filler includes titanium white, talc, glass powder and a heat stabilizer; after the filler is added to the silicone resin, the rotation speed is increased to 700-800 r / min, the stirring time is 8-10 minutes, and finally the rotation speed is reduced to 500-600 r / min and maintained for 4-9 minutes; the mixing of the silicone resin, the solvent and the auxiliary agent is promoted, and precipitation in the mixing process is prevented; finally, the silicone resin sol is obtained.

[0048] The silicone resin is prepared by mixing the modified epoxy resin with high temperature resistance with a silanol polymer containing both methyl and phenyl groups and heating, so that the obtained silicone resin has both high heat resistance and good heat preservation effect, and the working temperature can reach 700-900°C; the solvent and the auxiliary agent are further added to the silicone resin, so that the silicone resin can be fully dispersed and mixed, the uniformity of the high temperature resistant component is improved, and the bonding strength between the high temperature resistant component and other components is ensured.

[0049] The metal component includes nickel element and niobium element, and the metal component is formed by mixing the nickel element powder solid and the niobium element powder solid; specifically, the nickel element powder solid and the niobium element powder solid are mixed first, and then the mixed solid mixture is ground at a ball milling speed of 380 r / min for 8-10 hours, with a ball-to-material ratio of 7:2; in this way, the buffering effect and excessive crushing phenomenon in the grinding process can be reduced, the grinding efficiency is improved, and the powder solids can be uniformly mixed; after the grinding is completed, the ground niobium element powder solid and the ground nickel element powder solid are dried at 75-90°C, and finally the powder solid metal component with a diameter of 10-25 um is obtained through filtration and screening; in the metal component, the nickel element has a promoting effect on the decomposition of ammonia, and the nickel element has good corrosion resistance at room temperature; preferably, the content of the nickel element in the metal component is greater than that of the niobium element, so that the corrosion-resistant coating for the ammonia decomposition reactor can resist ammonia corrosion while promoting the decomposition of ammonia, thereby improving the conversion efficiency of ammonia; ammonia is decomposed into hydrogen and nitrogen; the niobium element in the metal component has good chemical stability, corrosion resistance and high temperature resistance; therefore, the metal component can improve the corrosion resistance of the corrosion-resistant coating for the ammonia decomposition reactor, and by adjusting the ratio of the niobium element and the nickel element in the metal component, the ammonia decomposition process is indirectly controlled; preferably, the mass percentage of the niobium element and the nickel element in the metal component is in the range of 1:3-1:8; similarly, the niobium element and the nickel element in the metal component also have a thermal conductivity of 90 W / (m.K) or more, respectively, and the metal component can also improve the overall thermal conductivity to provide more heat for the ammonia decomposition process; specifically, the metal component accounts for 25-35% of the mass of the corrosion-resistant coating for ammonia decomposition.

[0050] The ceramic component includes silicon element, carbon element and alumina, the silicon element accounts for 10-20% of the ceramic component, the carbon element accounts for 10-20% of the ceramic component, and the rest is alumina; further, the silicon element and the carbon element in the ceramic component are mixed in a ratio of 1:1, the silicon element and the carbon element exist in the form of a compound in the ceramic component, such as silicon carbide; the ceramic component is prepared by mixing alumina solid and silicon carbide solid first and then grinding the mixture by using a ball milling method; specifically, the silicon carbide powdery solid is mixed with the alumina powdery solid, and the mixture is ground at a ball milling speed of 380 r / min for 8-10 hours with a ball-to-material ratio of 7:2; thus, the grinding efficiency is improved by reducing the buffering effect and excessive crushing phenomenon in the grinding process, and then the ground silicon carbide powdery solid and the ground alumina powdery solid are dried at 75-90°C, and finally the powdery solid metal component with a diameter of 15-45 um is obtained through filtration and screening; wherein, since the silicon carbide and the alumina both have good corrosion resistance, and the silicon carbide and the alumina have melting points of 2700°C and 2000°C respectively, the ceramic component including the silicon carbide and the alumina has good corrosion resistance, high temperature resistance and high temperature stability, and can effectively prevent corrosion phenomena generated in the ammonia decomposition process; preferably, in the ceramic component, the mass percentage of the silicon carbide and the alumina is in the range of 2:3-1:4, so that the ceramic component has good corrosion resistance and good thermal conductivity, thereby better promoting the thermal decomposition of ammonia, improving the corrosion resistance in the ammonia environment, and promoting the decomposition reaction of ammonia.

[0051] After the preparation of the high-temperature-resistant component, the metal component and the ceramic component is completed respectively, as shown in the formula (I), the application also discloses a preparation method of a corrosion-resistant coating for ammonia decomposition. Figure 1 The preparation method of the corrosion-resistant coating for ammonia decomposition includes the following steps:

[0052] Step one: mix the high-temperature-resistant component, the metal component and the ceramic component, wherein the high-temperature-resistant component accounts for 35-55% of the total mass after mixing, the metal component accounts for 25-35% of the total mass after mixing, and the rest is the ceramic component;

[0053] Step two: stir the mixed high-temperature-resistant component, the metal component and the ceramic component at a speed of 100-150 r / min for 5-8 minutes to promote the preliminary diffusion of ions in the high-temperature-resistant component, the metal component and the ceramic component;

[0054] Step three: continue to stir the mixed high-temperature-resistant component, the metal component and the ceramic component after stirring in step two at a speed of 700-800 r / min for 8-10 minutes to promote the continued diffusion of ions in the high-temperature-resistant component, the metal component and the ceramic component;

[0055] Step four: stirring the mixed high-temperature-resistant component, metal component and ceramic component in step three at a speed of 500-600 r / min for 4-9 minutes to promote further diffusion of ions in the high-temperature-resistant component, metal component and ceramic component, and to obtain a basic composite coating;

[0056] Step five: adding water to the basic composite coating to adjust the viscosity of the basic composite coating, and to obtain a corrosion-resistant coating for ammonia decomposition.

[0057] By using different speeds and stirring times in steps two to four, specifically, first stirring at a low speed, then greatly increasing the speed and stirring time, and then gradually reducing the speed and stirring time, the high-temperature-resistant component, metal component and ceramic component can be fully dispersed and uniform, and the phenomenon of solid precipitation or aggregation in the mixing process is reduced; different speeds for stirring make the high-temperature-resistant component, metal component and ceramic component uniformly dispersed.

[0058] The preparation method of the corrosion-resistant coating for ammonia decomposition will be further described below in combination with examples:

[0059] Example 1

[0060] Step one: mixing the high-temperature-resistant component, metal component and ceramic component, wherein the high-temperature-resistant component accounts for 35% of the total mass after mixing, the metal component accounts for 25% of the total mass after mixing, and the ceramic component accounts for 40% of the total mass after mixing;

[0061] Step two: stirring the mixed high-temperature-resistant component, metal component and ceramic component at a speed of 100 r / min for 5 minutes to promote preliminary diffusion of ions in the high-temperature-resistant component, metal component and ceramic component;

[0062] Step three: stirring the mixed high-temperature-resistant component, metal component and ceramic component in step two at a speed of 700 r / min for 8 minutes to promote continued diffusion of ions in the high-temperature-resistant component, metal component and ceramic component;

[0063] Step four: stirring the mixed high-temperature-resistant component, metal component and ceramic component in step three at a speed of 500 r / min for 4 minutes to promote further diffusion of ions in the high-temperature-resistant component, metal component and ceramic component, and to obtain a basic composite coating;

[0064] Step five: adding water to the basic composite coating to adjust the viscosity of the basic composite coating, and to obtain a corrosion-resistant coating for ammonia decomposition.

[0065] Example 2

[0066] Step one: mixing the high-temperature-resistant component, the metal component and the ceramic component, wherein the high-temperature-resistant component accounts for 40% of the total mass after mixing, the metal component accounts for 30% of the total mass after mixing, and the ceramic component accounts for 30% of the total mass after mixing;

[0067] Step two: stirring the mixed high-temperature-resistant component, the metal component and the ceramic component at a speed of 120 r / min for 6 minutes to promote the initial diffusion of ions in the high-temperature-resistant component, the metal component and the ceramic component;

[0068] Step three: stirring the mixed high-temperature-resistant component, the metal component and the ceramic component after stirring in step two at a speed of 750 r / min for 9 minutes to promote the continued diffusion of ions in the high-temperature-resistant component, the metal component and the ceramic component;

[0069] Step four: stirring the mixed high-temperature-resistant component, the metal component and the ceramic component after stirring in step three at a speed of 550 r / min for 6 minutes to promote the further diffusion of ions in the high-temperature-resistant component, the metal component and the ceramic component, to obtain a basic composite coating;

[0070] Step five: adding water to the basic composite coating to adjust the viscosity of the basic composite coating, to obtain a corrosion-resistant coating for ammonia decomposition.

[0071] Example 3

[0072] Step one: mixing the high-temperature-resistant component, the metal component and the ceramic component, wherein the high-temperature-resistant component accounts for 55% of the total mass after mixing, the metal component accounts for 35% of the total mass after mixing, and the ceramic component accounts for 10% of the total mass after mixing;

[0073] Step two: stirring the mixed high-temperature-resistant component, the metal component and the ceramic component at a speed of 150 r / min for 8 minutes to promote the initial diffusion of ions in the high-temperature-resistant component, the metal component and the ceramic component;

[0074] Step three: stirring the mixed high-temperature-resistant component, the metal component and the ceramic component after stirring in step two at a speed of 800 r / min for 10 minutes to promote the continued diffusion of ions in the high-temperature-resistant component, the metal component and the ceramic component;

[0075] Step four: stirring the mixed high-temperature-resistant component, the metal component and the ceramic component after stirring in step three at a speed of 600 r / min for 9 minutes to promote the further diffusion of ions in the high-temperature-resistant component, the metal component and the ceramic component, to obtain a basic composite coating;

[0076] Step five: adding water to the basic composite coating to adjust the viscosity of the basic composite coating, to obtain a corrosion-resistant coating for ammonia decomposition.

[0077] The corrosion-resistant coating for ammonia decomposition prepared by Examples 1-3 is coated on the surface of a metal carrier, such as an ammonia decomposition reactor, and is placed in a room temperature condition for curing. After curing, the corrosion-resistant coating for ammonia decomposition is subjected to a heat conduction test. Specifically, metal carriers of the same size are prepared, and the same flow rate and temperature of gas is introduced into the metal carriers, which are heated in a 100°C environment. A heat flow sensor is used to detect the heat conduction coefficient of the metal carriers coated with different coatings. The test results are as follows:

[0078]

[0079] It can be seen that the heat conduction coefficient of the reactor 3, reactor 4, and reactor 5 coated with the corrosion-resistant coating for ammonia decomposition prepared by Examples 1-3 is in the range of 13.8-14 W / mK. Compared with the reactor 2 coated with the existing single inorganic high-temperature paint, the corrosion-resistant coating for ammonia decomposition prepared by Examples 1-3 can simultaneously improve the heat conduction coefficient of the reactor and promote the transfer of heat in the ammonia decomposition reactor, so as to better heat the ammonia and promote the thermal decomposition of the ammonia. Similarly, the reactor 3, reactor 4, and reactor 5 also have higher ammonia decomposition reaction efficiency compared with the reactor 1 and reactor 2.

[0080] Further, the corrosion-resistant coating for ammonia decomposition prepared by Examples 1-3 is coated on the surface of a metal carrier, such as an ammonia decomposition reactor, and is placed in a room temperature condition for curing. After curing, the corrosion-resistant coating for ammonia decomposition is subjected to an electrochemical test to verify the corrosion effect on the ammonia. Specifically, metal carriers of the same size are prepared, and the metal carriers are respectively connected to a 120V direct current power source. The same flow rate and temperature of ammonia is introduced into the metal carriers, and the current and voltage change trend in the metal carriers is detected. The test results are as follows:

[0081]

[0082] It can be seen that, compared with the reactor 1 and reactor 2, the reactor 3-reactor 5 coated with the corrosion-resistant coating for ammonia decomposition prepared by Examples 1-3 has a relatively slow change in current and voltage under the same voltage during the ammonia flow process. It can be seen that the reactor 1 and reactor 2 are severely corroded by ammonia during the ammonia flow process, thereby generating an oxide layer on the surface and affecting the change in current and voltage. The reactor 3-reactor 5 is less corroded by ammonia during the ammonia flow process, thereby having a smaller change in current and voltage.

[0083] The application further discloses the ammonia decomposition reactor comprising the corrosion-resistant coating for ammonia decomposition, and the corrosion-resistant coating for ammonia decomposition is covered on the inner surface of the ammonia decomposition reactor, the thickness of the corrosion-resistant coating for ammonia decomposition is equal to each other, and the thickness of the corrosion-resistant coating for ammonia decomposition ranges from 15 to 25 um.

[0084] Further, the inner surface of the ammonia decomposition reactor is subjected to sand blasting treatment of 40-mesh brown steel beads, the corrosion-resistant coating for ammonia decomposition is cleaned by anhydrous ethanol before being sprayed, is dried in a compressed air environment for at least 30 minutes after being cleaned, and is baked at 250 DEG C for 30 minutes or is solidified at normal temperature (20-25 DEG C) for 24 hours after being dried.

[0085] Obviously, the above examples are only examples for clearly illustrating the application, and are not intended to limit the application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. All the embodiments do not need to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the application.

Claims

1. A corrosion resistant coating for ammonia decomposition, which is composed of a high-temperature resistant component, a metal component and a ceramic component; characterized in that: the high-temperature resistant component comprises an organosilicon resin, a filler, a solvent and an additive, the organosilicon resin accounts for 50-60% of the high-temperature resistant component, the filler accounts for 20-30% of the high-temperature resistant component, and the rest is the solvent and the additive; the solvent is xylene, and the additive is a dispersing agent, an adhesion agent, an anti-settling thixotropic agent or an antifoaming agent; the organosilicon resin in the high-temperature resistant component is prepared by the following method, Step one: placing a chlorosilane mixture in an acidic environment below 25℃, and sequentially generating a plurality of silanols containing methyl or phenyl groups through hydrolysis reaction of the chlorosilane mixture and water, and continuously generating a silanol polymer containing a plurality of methyl groups and a plurality of phenyl groups through polycondensation reaction among the plurality of silanols containing methyl or phenyl groups; Step two: washing the obtained silanol polymer containing methyl and phenyl groups with water, and obtaining the silanol polymer containing methyl and phenyl groups by heating after washing; the silanol polymer containing methyl and phenyl groups is used as an intermediate; Step three: mixing and stirring the intermediate and a resin mixture to obtain an organosilicon resin gel, and further stirring the obtained organosilicon resin gel by adding water to obtain an organosilicon resin sol; the metal component comprises nickel and niobium, and the content of nickel in the metal component is greater than that of niobium; the ceramic component comprises silicon, carbon and alumina, the mass ratio of silicon to carbon is 1:1, and the alumina accounts for 60-80% of the ceramic component; the content of the high-temperature resistant component is 35-55%, the content of the high-temperature resistant component is greater than that of the metal component, and the content of the high-temperature resistant component is greater than that of the ceramic component; and the preparation method of the corrosion resistant coating for ammonia decomposition comprises the following steps: Step one: mixing the high-temperature resistant component, the metal component and the ceramic component, wherein the high-temperature resistant component accounts for 35-55% of the total mass after mixing, the metal component accounts for 25-35% of the total mass after mixing, and the rest is the ceramic component; Step two: stirring the mixed high-temperature resistant component, the metal component and the ceramic component at a speed of 100-150 r / min for 5-8 minutes; Step three: continuing to stir the mixed high-temperature resistant component, the metal component and the ceramic component after stirring in Step two at a speed of 700-800 r / min for 8-10 minutes; Step four: stirring the mixed high-temperature resistant component, the metal component and the ceramic component after stirring in Step three at a speed of 500-600 r / min for 4-9 minutes to obtain a base composite coating; and Step five: adding water to the base composite coating to obtain the corrosion resistant coating for ammonia decomposition. In Step one, the chlorosilane mixture is composed of methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane and diphenyldichlorosilane. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2. A corrosion resistant coating for ammonia decomposition according to claim 1, characterized by: ​ 3. A corrosion resistant coating for ammonia decomposition according to claim 1, characterized by: In step two, the obtained silanol polymer containing methyl and phenyl groups is washed with water and heated at a temperature of 100-150 DEG C; in step three, the resin mixture is a mixture of an epoxy resin and a high-temperature resistant resin or a high-temperature resistant modifier.

4. A corrosion resistant coating for ammonia decomposition according to claim 1, characterized by: The filler includes titanium white, talcum powder, glass powder and heat stabilizer.

5. A corrosion resistant coating for ammonia decomposition according to claim 1, characterized by: The mass percentage of niobium and nickel in the metal component ranges from 1:3 to 1:8, and the particle size of the metal component is 10-25 um.

6. A corrosion resistant coating for ammonia decomposition according to claim 1, characterized by: The ceramic component contains silicon carbide and alumina, and the mass percentage of silicon carbide and alumina ranges from 1:4 to 2:3, and the particle size of the ceramic component is 15-45 um.

7. An ammonia decomposition reactor containing the corrosion-resistant coating for ammonia decomposition according to any one of claims 1-6, characterized in that, The inner surface of the ammonia decomposition reactor is covered with the corrosion-resistant coating for ammonia decomposition, and the thickness of the corrosion-resistant coating for ammonia decomposition is equal to each other.

8. An ammonia decomposition reactor according to claim 7, characterized in that: The thickness of the corrosion-resistant coating for ammonia decomposition on the inner surface of the ammonia decomposition reactor ranges from 15 to 25 um.

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