Anti-silicon-plugging regenerative thermal incinerator exhaust gas treatment material and preparation method thereof

Abstract

The present application relates to the industrial waste gas treatment technical field, disclose the heat accumulation type thermal incinerator waste gas treatment material and preparation method thereof of anti silicon blockage, the material is made of kaolin, talc, calcined alumina matrix and pre-synthesized magnesium stabilized aluminum titanate clinker, monoclinic zirconium oxide, lithium feldspar modifier, the preparation method includes: the raw material is made into dry powder mixture, water ball milling pressure filtration is used to prepare mud cake, the plastic mud section is prepared by adding organic additives vacuum mud preparation; Extrusion molding is honeycomb green body with 10-13 cpsi of hole density and 1.4-1.6mm of wall thickness; Sintering at 1390-1410 DEG C, then quenching at 1100 DEG C to 700 DEG C interval control 5-8 DEG C / min rate. The present application uses the chemical inertia of monoclinic zirconium oxide to block silicon corrosion, and lithium feldspar promotes surface densification, combined with clinker and matrix thermal expansion mismatch and quenching process induced microcrack toughening, solves the problem of channel blockage and thermal shock cracking of heat accumulator under the working condition of waste gas containing silicon.

Description

Technical Field

[0001] This invention relates to the field of industrial waste gas treatment technology, specifically to a regenerative thermal incinerator waste gas treatment material and its preparation method that is resistant to silicon blockage. Background Technology

[0002] Regenerative thermal oxidizers (RTOs) are the mainstream equipment for treating industrial volatile organic compound (VOC) emissions. Emissions from industries such as semiconductor manufacturing, fine chemicals, and coating often contain volatile organosilicon compounds such as hexamethyldisiloxane. These organosilicon compounds decompose in the high-temperature oxidation chamber of the RTO, generating silica dust, which is then carried into the regenerator chamber by the high-temperature airflow.

[0003] Currently, most commonly used honeycomb ceramic heat storage elements are made of cordierite. During long-term operation, silica dust in the airflow is deposited on the pore walls of the heat storage element. Since the cordierite matrix is ​​mainly composed of magnesium oxide, aluminum oxide, and silica, under high-temperature conditions, the highly reactive silica dust easily reacts with the cordierite matrix to form low-melting-point magnesium aluminosilicate eutectic. This chemical erosion process leads to melting on the material surface, accompanied by the penetration of the glassy phase into the matrix, reducing the material's load softening temperature and structural strength.

[0004] As corrosion products and dust continue to accumulate, the cross-sectional area of ​​the regenerator's pores decreases, increasing the operating resistance of the regenerator system. Due to the chemical reaction and fusion bonding between silica and the ceramic matrix, the deposited layer is tightly bonded to the matrix, making it difficult to completely peel off using conventional backflushing cleaning methods. Furthermore, the uneven silica deposition layer causes localized thermal stress concentration in the regenerator during frequent heating and cooling cycles. Existing common cordierite materials have low fracture toughness and are unable to effectively resist this thermal stress, making them prone to thermal shock cracking or even complete collapse, affecting the normal operation of the equipment. Summary of the Invention

[0005] The technical problem solved by this invention is: when treating silicon-containing waste gas in a regenerative thermal incinerator, the silica dust generated by the decomposition of organosilicon is prone to react with the ceramic matrix at high temperature to form low-melting-point eutectic, which in turn leads to blockage of the regenerative body pores and structural corrosion and collapse.

[0006] To address the above problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a regenerative thermal incinerator exhaust gas treatment material resistant to silicon blockage, wherein the material is a honeycomb ceramic obtained by kneading, extrusion molding and sintering a dry powder mixture made from raw materials comprising the following weight percentages:

[0008] Kaolin: 38.0%–41.5%;

[0009] Talc: 36.0%~38.0%;

[0010] Calcined alumina: 14.0%–16.0%;

[0011] Magnesium-stabilized aluminum titanate clinker: 4.0%–6.0%;

[0012] Monoclinic zirconium oxide: 2.0%–3.0%;

[0013] Lithium feldspar: 0.5%–1.0%;

[0014] The sum of the weight percentages of the components is 100%;

[0015] The magnesium-stabilized aluminum titanate clinker is a powder synthesized in advance from alumina, titanium dioxide, magnesium oxide and iron oxide red through a high-temperature solid-phase reaction.

[0016] By adopting the above technical solution, a cordierite matrix is ​​constructed using kaolin, talc, and calcined alumina, and magnesium-stabilized aluminum titanate clinker, monoclinic zirconium oxide, and lithium feldspar are introduced as modifying components. The components work synergistically during sintering, and the specific mechanism is as follows:

[0017] Construction of the matrix principal crystalline phase: Kaolinite, talc, and calcined alumina undergo a solid-state reaction at high temperature to form cordierite (2MgO). 2Al2O3 The main crystalline phase is 5SiO2. This phase maintains a low coefficient of thermal expansion through the anisotropy of its lattice structure, providing basic thermal shock stability for the material and preventing thermal stress cracking caused by frequent RTO reversals.

[0018] The toughening and anti-wetting mechanism of magnesium-stabilized aluminum titanate as a second phase: Pre-synthesized magnesium-stabilized aluminum titanate (Al2TiO5) is introduced as second-phase particles distributed in the matrix. Due to the thermal expansion coefficient mismatch between the aluminum titanate crystalline phase and the cordierite matrix, a microcrack network is induced at the grain boundaries during cooling. When the material is subjected to thermal shock, the microcracks absorb fracture energy through deflection and bifurcation, significantly improving the fracture toughness of the material. In addition, the titanium-rich crystalline phase has a larger wetting angle with the acidic silica melt, reducing the adhesion of silica dust to the ceramic surface, making it difficult for the dust to spread and penetrate the surface.

[0019] Chemical blocking effect of monoclinic zirconia: Dispersed monoclinic zirconia particles are chemically inert, forming diffuse barrier points within the cordierite matrix. When silica dust attempts to undergo a eutectic reaction with cordierite, the dispersed zirconia particles interrupt the continuous path of liquid-phase corrosion, hindering the penetration of the low-melting-point glass phase into the ceramic interior.

[0020] The liquid-phase densification effect of lithium feldspar: During sintering, lithium feldspar forms a transient liquid phase, promoting particle rearrangement and mass transfer, reducing porosity, and making the microstructure of the sintered honeycomb ceramic surface smoother and denser. The dense surface reduces the mechanical sticking points of silica dust, making it easier for it to fall off under airflow, thus achieving an anti-clogging effect.

[0021] Preferably, the magnesium-stabilized aluminum titanate clinker is made from an initial raw material comprising the following molar ratio: α-alumina powder: rutile titanium dioxide: light magnesium oxide: iron oxide red = 1.0:(0.85~0.95):(0.05~0.15):(0.02~0.05).

[0022] By adopting the above technical solution and strictly controlling the synthesis reaction according to the stoichiometric ratio, Mg2+ and Fe2+ are utilized. 3+ Ions enter the aluminum titanate lattice to form a substitutional solid solution. This solid solution effectively inhibits the degradation of aluminum titanate at 800℃. Eutectoid decomposition reaction in the 1280℃ range (Al2TiO5→α) Al2O3+TiO2) ensures the stability of the clinker's phase structure at the RTO operating temperature; trace amounts of iron oxide red reduce the activation energy of the solid-phase reaction, promote complete grain development, reduce grain boundary defects, and improve the clinker's resistance to erosion.

[0023] Preferably, the preparation process of the magnesium-stabilized aluminum titanate clinker includes: placing the initial raw materials into a ball mill jar, adding deionized water as the medium, and ball milling and mixing for 12-16 hours to obtain a mixed slurry; spray drying, granulation, and pressing the mixed slurry to obtain green blocks; placing the green blocks in a high-temperature kiln, heating to 1480℃-1520℃ and holding for 6-8 hours to carry out a solid-phase synthesis reaction to obtain synthesized clinker; and mechanically crushing, ball milling, and air classifying the synthesized clinker to obtain magnesium-stabilized aluminum titanate clinker with a particle size distribution D50 of 5.0μm-8.0μm.

[0024] By adopting the above technical solution, and employing a process of high-pressure densification followed by high-temperature calcination, the diffusion distance between reacting ions is shortened, the solid-phase reaction conversion rate is improved, and free TiO2 residue is avoided. The final clinker particle size D50 is controlled within the range of 5.0 μm to 8.0 μm. This particle size allows the clinker particles to act as effective stress-relieving centers in the matrix, playing a role in microcrack toughening, while preventing failure due to excessively fine particles completely dissolving in the matrix glass phase.

[0025] Preferably, the material is a honeycomb ceramic structure with a pore density of 10-13 cpsi and a wall thickness of 1.4-1.6 mm.

[0026] By adopting the above technical solution, a large-diameter, thick-walled pore structure is designed for high-dust working conditions. The low pore density of 10–13 cpsi increases the cross-sectional area of ​​a single pore, reducing the probability of dust bridging and clogging; the wall thickness of 1.4 mm–1.6 mm provides higher mechanical strength, enabling it to withstand thermal stress concentration caused by local silicon deposition and airflow impact during dust removal and backflushing.

[0027] Secondly, the present invention provides a method for preparing a silicon-resistant regenerative thermal incinerator waste gas treatment material, comprising the following steps:

[0028] Kaolin, talc, and calcined alumina were weighed according to the formula as matrix raw materials, and magnesium-stabilized aluminum titanate clinker, monoclinic zirconium oxide, and lithium feldspar were added as modifying raw materials. The above raw materials were mixed to obtain a dry powder mixture.

[0029] Deionized water is added to the dry powder mixture for ball milling dispersion. After dehydration by pressure filtration, mud cake is obtained. Organic additives are added to the mud cake, and the mixture is aged and kneaded in a vacuum plow to obtain plastic mud segments.

[0030] The plastic clay segment is extruded and shaped using an extrusion die, and after drying, a honeycomb ceramic green body is obtained.

[0031] The honeycomb ceramic green body is placed in a tunnel kiln for sintering. After sintering, it is cooled to 1100°C with the furnace. Then, a fan is turned on in the range of 1100°C to 700°C for rapid cooling and shaping. Finally, it is cooled to room temperature to obtain the silicon-resistant regenerative thermal incinerator waste gas treatment material.

[0032] By adopting the above technical solution and utilizing a process path that combines physical dispersion and chemical reaction, the precise construction of the material's microstructure is ensured.

[0033] First, a process of dry mixing followed by wet ball milling is adopted to achieve submicron-level uniform dispersion of modified raw materials with large density differences (especially high-density monoclinic zirconium oxide) in the matrix raw material, preventing uneven local thermal expansion coefficients after sintering due to component segregation.

[0034] Secondly, by precisely controlling the rheological properties of the clay through pressure filtration dewatering and vacuum clay refining processes, the gas trapped inside the clay is removed, and microscopic pore defects are eliminated, thus ensuring the green strength and density of the honeycomb thin-walled structure.

[0035] Finally, the matrix phase transformation is completed through a specific sintering process, and the stress state of the second phase is controlled by a rapid cooling process, ultimately obtaining a multiphase ceramic with both erosion resistance and high seismic resistance.

[0036] Preferably, in the step of sintering the honeycomb ceramic green body, the specific process parameters are: heating to 1390℃~1410℃ and holding for 5~6 hours.

[0037] By adopting the above technical solution, the temperature range and holding time are determined based on the solid-phase reaction kinetics of cordierite formation. Within the temperature range of 1390℃ to 1410℃, kaolin, talc, and alumina in the raw materials decompose and recrystallize, undergoing the following main phase-forming reaction: 2(3MgO) 4SiO2 H2O)+4(Al2O3 2SiO2 2H₂O) + 2Al₂O₃ → 3(2MgO) 2Al2O3 5SiO2) + SiO2 + 10H2O (↑) (Note: The above reaction formula is a simplified description of the overall phase formation process. In the actual reaction, the intermediate phases mullite and enstatite are generated and consumed.)

[0038] Sintering within this temperature range maximizes the formation rate of the cordierite main crystalline phase, ensuring the material achieves the expected low thermal expansion properties. If the temperature is below 1390℃, the reaction is incomplete, and the residual alumina or quartz phase will increase the coefficient of thermal expansion; if the temperature is above 1410℃, excessive liquid phase will cause the honeycomb structure to soften, deform, or even collapse of the pores.

[0039] Preferably, in the rapid cooling and shaping step, the cooling rate is controlled to be 5°C / min to 8°C / min.

[0040] By adopting the above technical solution, a microcrack toughening mechanism is introduced into the material through a rapid cooling process. This is because magnesium stabilizes aluminum titanate (… ≈ 2.0×10 -6 / ℃) and cordierite matrix ( ≈1.5×10 -6 There is a significant difference in the coefficient of thermal expansion between 1100℃ and 700℃, resulting in a tensile stress field at the grain boundaries during cooling. When rapidly cooled at a rate of 5℃ / min to 8℃ / min within the viscoelastic transition range of 1100℃ to 700℃, the thermal stress cannot be relaxed through lattice creep, thus inducing microcracks around the aluminum titanate particles. These pre-existing microcracks can absorb elastic energy through crack deflection and branching during subsequent service life, hindering the propagation of the main crack and significantly improving the material's thermal shock resistance.

[0041] Preferably, in the step of preparing the mud cake, the moisture content of the mud cake is controlled to be 22% to 24%; in the step of preparing the plastic mud segment, the organic additives include 4.0% to 4.5% hydroxypropyl methylcellulose and 2.0% to 2.5% glycerol relative to the weight of the mud cake.

[0042] By adopting the above technical solution, a plastic rheological system suitable for thin-walled honeycomb ceramic extrusion was constructed. A moisture content of 22%–24% provides the liquid film medium required for particle movement. Hydroxypropyl methylcellulose acts as a binder; its long-chain molecules expand in water to form a three-dimensional network structure, encapsulating ceramic particles and increasing the yield stress of the clay, thus ensuring sufficient shape retention in the extruded green body. Glycerin acts as a lubricant, reducing the coefficient of internal friction between the clay and the die wall, as well as between the particles, thereby reducing extrusion resistance and die wear, improving the surface smoothness of the green body, and reducing stress concentration points caused by surface roughness.

[0043] Preferably, in the step of preparing the honeycomb ceramic green body, the drying treatment includes microwave drying and hot air drying, and the moisture content of the honeycomb ceramic green body is controlled to be less than 1%.

[0044] By adopting the above technical solution, a combined internal and external drying strategy is employed to address the drying cracking problem of thick-walled honeycomb ceramics. Microwave drying utilizes the principle of dielectric loss, causing water molecules inside the green body to be directly heated and vaporized, migrating outwards to form a positive temperature and humidity gradient, preventing surface hardening from sealing in internal moisture. This is followed by hot air drying to remove residual surface moisture. By controlling the final moisture content to below 1%, the steam pressure generated by the intense vaporization of moisture during the initial stage of high-temperature sintering can be prevented from causing the green body to crack, ensuring a high yield of sintered products.

[0045] This invention provides a silicon-resistant regenerative thermal incinerator waste gas treatment material and its preparation method. It has the following beneficial effects:

[0046] 1. This invention significantly improves the material's resistance to silicon corrosion and clogging by introducing monoclinic zirconium oxide and lithium feldspar into a cordierite matrix. The monoclinic zirconium oxide particles, as chemically inert phases, are dispersed in the matrix, cutting off the continuous path of the reaction between silica dust and cordierite to form low-melting-point eutectic, thus blocking the penetration of liquid phase corrosion into the ceramic interior. At the same time, lithium feldspar promotes the formation of a dense and smooth surface during sintering. Combined with the large wetting angle of magnesium-stabilized aluminum titanate crystals relative to acidic silicon melt, it reduces the physical adhesion and mechanical anchoring depth of silica dust on the ceramic surface, thereby solving the problem of pore blockage and structural corrosion caused by the adhesion reaction of silica dust in the heat storage body.

[0047] 2. This invention utilizes magnesium to stabilize the thermal expansion coefficient mismatch between aluminum titanate and the cordierite matrix, and in conjunction with a rapid cooling process, constructs a microcrack toughening mechanism within the material. By dissolving magnesium and iron ions in the crystal lattice, the chemical stability of the aluminum titanate second phase under high-temperature conditions is ensured. The microcrack network generated during the cooling process after sintering absorbs fracture energy through crack deflection and bifurcation when the material is subjected to thermal shock, alleviating the thermal stress concentration caused by equipment reversal and local silicon deposition, preventing thermal shock fracture of the material, and extending its service life.

[0048] 3. This invention employs a pre-synthesized clinker process combined with thick-walled, large-pore structural parameters to ensure the mechanical strength and structural stability of the honeycomb ceramic. The magnesium-stabilized aluminum titanate clinker is pre-synthesized at high temperature and its particle size is controlled, eliminating the volume effect defects caused by in-situ reactions. Combined with a low pore density of 10–13 cpsi and a thick wall of 1.4 mm–1.6 mm, the material is endowed with high axial compressive strength and flexural strength, enabling it to withstand the airflow impact and accumulated dust load during high-pressure backflushing cleaning of the RTO system, thus preventing the heat storage body from collapsing or breaking during use. Detailed Implementation

[0049] Preparation Examples 1-3:

[0050] Preparation Example 1:

[0051] This preparation example provides a magnesium-stabilized aluminum titanate clinker, and the specific preparation process is as follows:

[0052] α-alumina powder, rutile titanium dioxide, light magnesium oxide and iron oxide red were weighed out as initial raw materials according to a molar ratio of 1.0:0.85:0.05:0.02.

[0053] The initial raw materials were placed in a ball mill jar, and deionized water was added as the medium for ball milling and mixing for 12 hours to obtain a mixed slurry.

[0054] The mixed slurry was spray-dried and granulated, and then pressed under a pressure of 100 MPa to obtain green blocks;

[0055] The green block was placed in a high-temperature kiln, heated to 1480℃ and held for 6 hours to carry out a solid-phase synthesis reaction, and the synthesized clinker was obtained.

[0056] The synthesized clinker was subjected to mechanical crushing, ball milling and air classification to obtain magnesium-stabilized aluminum titanate clinker with a particle size distribution D50 of 5.0 μm.

[0057] Preparation Example 2:

[0058] This preparation example provides a magnesium-stabilized aluminum titanate clinker, and the specific preparation process is as follows:

[0059] α-alumina powder, rutile titanium dioxide, light magnesium oxide and iron oxide red were weighed out as initial raw materials according to a molar ratio of 1.0:0.90:0.10:0.035.

[0060] The initial raw materials were placed in a ball mill jar, and deionized water was added as the medium for ball milling and mixing for 14 hours to obtain a mixed slurry.

[0061] The mixed slurry was spray-dried and granulated, and then pressed under a pressure of 100 MPa to obtain green blocks; the green blocks were placed in a high-temperature kiln, heated to 1500℃ and held for 7 hours to carry out a solid-phase synthesis reaction to obtain synthesized clinker.

[0062] The synthesized clinker was subjected to mechanical crushing, ball milling and air classification to obtain magnesium-stabilized aluminum titanate clinker with a particle size distribution D50 of 6.5 μm.

[0063] Preparation Example 3:

[0064] This preparation example provides a magnesium-stabilized aluminum titanate clinker, and the specific preparation process is as follows:

[0065] α-alumina powder, rutile titanium dioxide, light magnesium oxide and iron oxide red were weighed out as initial raw materials according to a molar ratio of 1.0:0.95:0.15:0.05.

[0066] The initial raw materials were placed in a ball mill jar, and deionized water was added as the medium for ball milling and mixing for 16 hours to obtain a mixed slurry. The mixed slurry was spray-dried and granulated, and then pressed under a pressure of 100 MPa to obtain green blocks.

[0067] The green block was placed in a high-temperature kiln, heated to 1520℃ and held for 8 hours to carry out a solid-phase synthesis reaction, and the synthesized clinker was obtained.

[0068] The synthesized clinker was subjected to mechanical crushing, ball milling and air classification to obtain magnesium-stabilized aluminum titanate clinker with a particle size distribution D50 of 8.0 μm.

[0069] Examples 1-3:

[0070] Example 1:

[0071] This embodiment provides a regenerative thermal incinerator exhaust gas treatment material resistant to silicon blockage and its preparation method, including the following steps:

[0072] S1. Weigh 41.5% kaolin, 38.0% talc, and 14.0% calcined alumina as base materials by total weight percentage, and add 4.0% magnesium-stabilized aluminum titanate clinker prepared in Preparation Example 1, 2.0% monoclinic zirconium oxide, and 0.5% lithium feldspar as modifying materials. Mix the above materials to obtain a dry powder mixture.

[0073] S2. Add deionized water to the dry powder mixture and disperse it by ball milling. After dehydration by pressure filtration, a mud cake with a moisture content of 22% is obtained. Add 4.0% hydroxypropyl methylcellulose and 2.0% glycerol to the mud cake, and age and knead it in a vacuum pumice machine to obtain a plastic mud segment without internal air bubbles.

[0074] S3. The plastic clay segment is extruded through an extrusion die with a pore density of 10 cpsi and a wall thickness of 1.4 mm. After microwave drying and hot air drying, a honeycomb ceramic green body with a moisture content of less than 1% is obtained.

[0075] S4. The honeycomb ceramic green body is placed in a tunnel kiln and heated to 1390℃ at a rate of 2℃ / min and held for 5 hours for sintering. Then it is cooled to 1100℃ with the furnace. In the range of 1100℃ to 700℃, the fan is turned on to control the cooling rate at 5℃ / min for rapid cooling and shaping. Finally, it is cooled to room temperature to obtain a regenerative thermal incinerator waste gas treatment material resistant to silicon blockage.

[0076] Example 2:

[0077] This embodiment provides a regenerative thermal incinerator exhaust gas treatment material resistant to silicon blockage and its preparation method, including the following steps:

[0078] S1. Weigh 40.0% kaolin, 36.7% talc, and 15.0% calcined alumina as base materials by total weight percentage, and add 5.0% magnesium-stabilized aluminum titanate clinker obtained in Preparation Example 2, 2.5% monoclinic zirconium oxide, and 0.8% lithium feldspar as modifying materials. Mix the above materials to obtain a dry powder mixture.

[0079] S2. Add deionized water to the dry powder mixture and disperse it by ball milling. After dehydration by pressure filtration, a mud cake with a moisture content of 23% is obtained. Add 4.2% hydroxypropyl methylcellulose and 2.2% glycerol to the mud cake, and age and knead it in a vacuum pumice machine to obtain a plastic mud segment without internal air bubbles.

[0080] S3. The plastic clay segment is extruded through an extrusion die with a pore density of 12 cpsi and a wall thickness of 1.5 mm. After microwave drying and hot air drying, a honeycomb ceramic green body with a moisture content of less than 1% is obtained.

[0081] S4. The honeycomb ceramic green body is placed in a tunnel kiln and heated to 1400℃ at a rate of 2℃ / min and held for 5.5 hours for sintering. Then it is cooled to 1100℃ with the furnace. In the range of 1100℃ to 700℃, the fan is turned on to control the cooling rate at 6.5℃ / min for rapid cooling and shaping. Finally, it is cooled to room temperature to obtain a regenerative thermal incinerator waste gas treatment material resistant to silicon blockage.

[0082] Example 3:

[0083] This embodiment provides a regenerative thermal incinerator exhaust gas treatment material resistant to silicon blockage and its preparation method, including the following steps:

[0084] S1. Weigh 38.0% kaolin, 36.0% talc, and 16.0% calcined alumina as base materials by total weight percentage, and add 6.0% magnesium-stabilized aluminum titanate clinker obtained in Preparation Example 3, 3.0% monoclinic zirconium oxide, and 1.0% lithium feldspar as modifying materials. Mix the above materials to obtain a dry powder mixture.

[0085] S2. Add deionized water to the dry powder mixture and disperse it by ball milling. After dehydration by pressure filtration, a mud cake with a moisture content of 24% is obtained. Add 4.5% hydroxypropyl methylcellulose and 2.5% glycerol to the mud cake, and age and knead it in a vacuum pumice machine to obtain a plastic mud segment without internal air bubbles.

[0086] S3. The plastic clay segment is extruded through an extrusion die with a pore density of 13cpsi and a wall thickness of 1.6mm. After microwave drying and hot air drying, a honeycomb ceramic green body with a moisture content of less than 1% is obtained.

[0087] S4. The honeycomb ceramic green body is placed in a tunnel kiln and heated to 1410℃ at a rate of 2℃ / min and held for 6 hours for sintering. Then it is cooled to 1100℃ with the furnace. In the range of 1100℃ to 700℃, the fan is turned on to control the cooling rate at 8℃ / min for rapid cooling and shaping. Finally, it is cooled to room temperature to obtain a regenerative thermal incinerator waste gas treatment material resistant to silicon blockage.

[0088] Comparative Examples 1-5:

[0089] Comparative Example 1:

[0090] Compared with Example 2, the difference is that magnesium was not added to stabilize aluminum titanate clinker, and it was replaced with an equal mass of calcined alumina powder. The remaining components and preparation process are the same.

[0091] Comparative Example 2:

[0092] Compared with Example 2, the difference is that monoclinic zirconium oxide (m-ZrO2) was not added, but replaced with an equal mass of kaolin. The remaining components and preparation process are the same.

[0093] Comparative Example 3:

[0094] Compared with Example 2, the difference is that no lithium feldspar was added, while the other components and preparation process are the same.

[0095] Comparative Example 4:

[0096] Compared with Example 2, the difference is that: instead of using pre-synthesized magnesium-stabilized aluminum titanate clinker in the raw materials, a mixture of pure alumina powder, titanium dioxide powder and magnesium oxide powder with the same stoichiometric ratio as the clinker is directly added; and in the S4 sintering cooling stage, the quenching fan is not turned on, and natural cooling with the furnace is adopted (cooling rate <2℃ / min), while the rest are the same.

[0097] Comparative Example 5:

[0098] Compared with Example 2, the difference is that in the heat storage chamber filling step, the 150-200mm cavity buffer zone and high-temperature alloy interception mesh in the middle layer are eliminated, and the anti-silicon blockage filler is directly stacked on the bottom conventional ceramic. All other aspects are the same.

[0099] Test Examples 1-4:

[0100] Test Example 1: Simulated Silicon Junction Shell Peeling Efficiency Test

[0101] Experimental procedure:

[0102] The honeycomb ceramics prepared in Examples 1 to 3 and Comparative Examples 1 and 3 were cut into... The standard test blocks are ultrasonically cleaned and dried before use.

[0103] A fused silica powder suspension with a solid content of 60% was prepared and uniformly sprayed onto the surface of the internal channels of the test block using a high-pressure spray gun, controlling the spraying amount. The test block was then placed in a high-temperature muffle furnace and held at 1050℃ for 2 hours to allow the silica powder to form a dense sintered glaze layer on the ceramic surface. After cooling, the mass of the test block was weighed and recorded as follows. The initial attached silicon junction mass was calculated. .

[0104] The silicon-coated test block was placed in a tube furnace, heated to 800°C and held for 30 minutes.

[0105] Using a specially designed pulse nozzle probe inserted into the furnace chamber, directly facing the axial direction of the test block channel, an online cleaning cycle is performed: first, atomized water (pressure 0.4MPa, flow rate 0.3L / min) is sprayed for 1.5 seconds, followed by dry compressed air (pressure 0.7MPa) for 4.0 seconds;

[0106] The above process is defined as one pulse cycle, and each test block is executed continuously for 5 pulse cycles.

[0107] After cleaning, remove the test block and allow it to cool naturally to room temperature. After drying, weigh the test block and record the mass as follows: .

[0108] Calculate the residual mass of silicon junction shell And according to the formula Calculate the crust peeling rate .

[0109] Table 1. Test results of simulated silicon junction peeling efficiency for each group of samples.

[0110]

[0111] According to the data in Table 1, after 5 cleaning cycles, the silicon junction shell peeling rate of Examples 1 to 3 remained above 92%, with Example 2 reaching 96.79%. The peeling rate of Comparative Example 1 was 6.53%, and the peeling rate of Comparative Example 3 was 37.26%.

[0112] Data indicates that the difference between Example Group and Comparative Example 1 stems from the thermoelastic mismatch introduced by the magnesium-stabilized aluminum titanate phase. When water mist contacts the surface, the low-expansion-coefficient ceramic matrix exhibits minimal volume change, while the attached high-expansion-coefficient silica layer shrinks. The shear stress generated at the interface causes the crust to fracture and detach. Comparative Example 1, lacking the low-expansion phase, cannot generate a sufficient stress difference, resulting in residue.

[0113] Comparing the examples and Comparative Example 3, it is evident that the surface self-glazing mechanism introduced by lithium feldspar affects the exfoliation effect. The liquid-phase glaze layer formed in the examples seals the surface openings and pores, reducing roughness and decreasing the penetration of molten silicon into the matrix and mechanical adhesion. Although Comparative Example 3 contains a thermally mismatched phase, the lack of lithium feldspar results in surface roughness, and the silicon crust forms a physical interlock with the matrix, hindering the exfoliation process. Examples 1 to 3 maintained high exfoliation rates within the set composition and process range, indicating that the material system possesses stability in terms of micro-stress field construction and surface anti-adhesion properties.

[0114] Test Example 2: Thermal Shock Resistance Stability and Strength Retention Rate Test

[0115] Experimental procedure:

[0116] The honeycomb ceramics prepared in Examples 1 to 3 and Comparative Example 2 were selected and cut into cylindrical samples with a diameter of 50 mm and a height of 50 mm. Ten parallel samples were selected from each group.

[0117] First, a small amount of fragment samples were taken from each group, ground into powder, and the specific heat capacity of the material at 100°C was tested using a differential scanning calorimeter (DSC). ( ), to assess the basic heat storage capacity of the material.

[0118] Subsequently, using a universal testing machine, the axial compressive strength of five specimens was tested according to the JC / T 686-2008 standard "Cellular Ceramics", and the average value was recorded as the initial strength. .

[0119] The remaining 5 samples were placed in a high-temperature resistance furnace and heated to 850°C at a rate of 10°C / min and held for 20 minutes to homogenize the overall temperature of the samples.

[0120] The honeycomb ceramics prepared in Examples 1 to 3 and Comparative Example 2 were selected and cut into cylindrical samples with a diameter of 50 mm and a height of 50 mm. Ten parallel samples were selected from each group.

[0121] First, a small amount of fragment samples were taken from each group, ground into powder, and the specific heat capacity of the material at 100°C was tested using a differential scanning calorimeter (DSC). ( ), to assess the basic heat storage capacity of the material.

[0122] Subsequently, using a universal testing machine, the axial compressive strength of five specimens was tested according to the JC / T 686-2008 standard "Cellular Ceramics", and the average value was recorded as the initial strength. .

[0123] The remaining 5 samples were placed in a high-temperature resistance furnace and heated to 850°C at a rate of 10°C / min and held for 20 minutes to homogenize the overall temperature of the samples.

[0124] The high-temperature sample was removed and placed on a rapid cooling platform. An industrial nozzle was used to spray a mixture of air and water mist onto the sample end face (water flow rate 0.5 L / min, air pressure 0.6 MPa) to reduce the surface temperature to below 100°C within 30 seconds. Then, compressed air was used to dry the surface moisture, and the sample was reheated in an 850°C furnace.

[0125] Repeat the heating and rapid cooling process described above for a total of 50 thermal shock cycles.

[0126] After the 50th cycle is completed and the sample has cooled to room temperature, the appearance of cracks is checked, and the residual axial compressive strength is tested. The average value is recorded as follows: .

[0127] According to the formula Calculate strength retention rate .

[0128] Table 2. Results of thermal shock resistance tests for each group of samples

[0129]

[0130] According to the data in Table 2, Examples 1 to 3 all exhibited excellent performance in terms of thermal properties and mechanical stability. The specific heat capacity of each example at 100°C exceeded 910 J / kg·K, which is superior to Comparative Example 2 and conventional cordierite materials (typically around 800-900 J / kg·K). This indicates that the introduced modified components did not reduce the heat storage density of the material; on the contrary, the density optimization slightly increased it, ensuring the heat recovery efficiency of the RTO system.

[0131] Regarding thermal shock resistance, Examples 1 to 3 maintained a strength retention rate of over 86% after 50 cycles of rapid cooling from 850°C to 100°C, and the specimens remained intact. Example 2 had an initial strength of 18.35 MPa and a residual strength of 16.82 MPa after cycling, with a retention rate of 91.66%. Comparative Example 2 had an initial strength of 15.90 MPa, close to the examples, but its strength decreased to 4.35 MPa after thermal cycling, with a retention rate of 27.36%, and a through-crack was observed.

[0132] The data differences between the examples and Comparative Example 2 demonstrate that the zirconia phase transformation toughening mechanism plays a role in maintaining the structural integrity of the material. In this technical solution, an aluminum titanate crystalline phase with a low coefficient of thermal expansion is introduced to achieve silicon junction shell peeling. This crystalline phase introduces microscopic thermal mismatch stress within the matrix. The monoclinic zirconia distributed in the examples (containing some metastable tetragonal phase) plays a stress absorption role during rapid cooling. When the stress field at the crack tip triggers the metastable tetragonal zirconia to transform into a monoclinic phase (t→m), the accompanying volume expansion generates a compressive stress field in the crack tip region, closing the microcrack and dissipating the propagation energy, thus inhibiting the formation of macroscopic cracks. Comparative Example 2 did not add zirconia components, and the matrix could not buffer the thermal stress generated by the temperature difference and the anisotropy of aluminum titanate, causing the crack to propagate and penetrate during cycling, leading to structural failure. This invention, by introducing a phase transformation toughening mechanism, maintains the material's mechanical strength under thermal cycling conditions while ensuring its anti-peeling properties.

[0133] Test Example 3: Performance Degradation Test After High-Temperature Aging

[0134] Experimental procedure:

[0135] The honeycomb ceramics prepared in Example 2 and Comparative Example 4 were selected as test objects. Ten samples were selected from each group and cut into thermal expansion coefficient test strips of 5mm×5mm×50mm and peel performance test blocks of 50mm×50mm×50mm. First, the average thermal expansion coefficient (CTE) of the two groups of samples was tested using a high-temperature horizontal dilatometer in the range of room temperature to 1000℃, and the CTE before aging was recorded.

[0136] Take another set of test blocks that have not undergone peeling test, and test their initial silicon junction peeling rate according to the method of Test Example 1. Record it as the peeling rate before aging.

[0137] The remaining samples and test blocks were then placed in a high-temperature box-type resistance furnace and heated to 1000°C in an air atmosphere, and kept at a constant temperature for 200 hours to simulate the long-term service condition of the RTO heat storage body in the high-temperature zone (accelerated aging test).

[0138] After aging, the sample was cooled to room temperature in the furnace. The coefficient of thermal expansion of the aged sample was measured again using a dilatometer and recorded as the CTE after aging.

[0139] The aged test blocks were then subjected to silicon coating and pulse cleaning operations again, and their regeneration capacity after high-temperature service was measured and recorded as the peeling rate after aging.

[0140] Experimental data:

[0141] Table 3. Evolution of thermal expansion coefficient and peel performance before and after high-temperature aging

[0142]

[0143] Note: "--" indicates that there is no data or the item is not applicable.

[0144] Results Analysis and Conclusions:

[0145] According to the data in Table 3, Example 2 exhibited stable performance after undergoing an aging treatment at 1000°C for 200 hours. Its coefficient of thermal expansion (CTE) decreased from -0.92 × 10⁻⁶ to 0.92 × 10⁻⁶. -6 / ℃ drifted to -0.78×10 -6 / ℃, maintaining negative expansion characteristics; the corresponding silicon junction shell peeling rate decreased from 96.79% to 94.12%, with a decrease of 2.76%, indicating that the material retained the peeling function.

[0146] Comparative Example 4 showed a change in performance after aging. Its CTE decreased from the initial -0.35 × 10⁻⁶. -6 / ℃ rose to 7.65×10 -6 / ℃, transforming into a high-expansion material; the peeling rate decreased from 78.44% to 12.33%, losing its anti-silicon blockage ability.

[0147] The data discrepancies stem from the impact of magnesium stabilization treatment and rapid quenching on the stability of the aluminum titanate crystal phase. Pure aluminum titanate tends to decompose in the temperature range of 750℃ to 1280℃ (Al₂TiO₅→Al₂O₃+TiO₂). The decomposition products, corundum and rutile, are both phases with high coefficients of thermal expansion. Comparative Example 4, without the introduction of magnesium ions for solid solution stabilization and employing a slow quenching process, resulted in the decomposition of aluminum titanate grains during aging, leading to an increase in the overall CTE of the material and the loss of the thermoelastic mismatch mechanism with the silica crust. Example 2, through magnesium ion solid solution, reduced the lattice distortion energy, and combined with the rapid quenching process, stabilized the crystal structure, suppressed the decomposition process, and ensured the microstructural stability of the material under long-term high-temperature service.

[0148] Test Example 4: System Voltage Drop Recovery and Anti-Secondary Blockage Simulation

[0149] Experimental procedure:

[0150] A vertical flow channel cold-state simulation device was constructed, consisting of a variable frequency fan, a flow stabilization section, a test section with a cross-sectional size of 150mm×150mm, and a differential pressure transmitter. A 300mm high layer of conventional dense cordierite honeycomb ceramic (40 holes / square inch, 2.5mm pore diameter) was installed at the bottom of the test section as the heat absorption section simulating the bottom layer of the heat storage chamber.

[0151] The anti-silicone blockage filler (10 pores / square inch, pore diameter 6.0 mm) prepared in Example 2 was selected as the top anti-fouling section, and about 10 g of sintered silica shell was preloaded on its surface.

[0152] Example 2: A 150mm high cavity buffer zone is set between the bottom layer and the top layer, and a 10-mesh (1.0mm wire diameter) high-temperature resistant alloy interception mesh is installed at the bottom of the buffer zone;

[0153] Comparative Example 5 eliminates the buffer zone and alloy mesh, directly stacking the top layer of the load-bearing shell onto the bottom ceramic layer. The fan is turned on and the cross-sectional velocity is adjusted to 1.5 m / s. After the flow field stabilizes, the initial system pressure drop is recorded. .

[0154] A powerful backflushing (0.7 MPa, 0.5 s) was performed on the top layer of packing using a pulse air gun to simulate crust stripping caused by online cleaning. The blower continued to run, and the dynamic pressure drop curve was recorded within 5 minutes after backflushing. After the reading stabilized, the final pressure drop after cleaning was recorded. The device was disassembled and the physical blockage area ratio of the bottom ceramic end face was statistically analyzed.

[0155] Experimental data:

[0156] Table 4. Test data on system voltage drop recovery and underlying congestion.

[0157]

[0158] Results Analysis and Conclusions:

[0159] Based on the data analysis in Table 4, there are differences in the hydrodynamic response between Example 2 and Comparative Example 5 after the cleaning pulse is triggered. In Comparative Example 5, the system pressure drop increases from approximately 185 Pa initially to over 680 Pa at the moment of shell peeling. Physical inspection confirms that silica fragments (2-10 mm in size) peeled from the top layer fall directly onto the bottom ceramic surface. Because the fragment size is close to or larger than the micropore diameter of the bottom layer (2.5 mm), the fragments become stuck inside the pores or accumulate on the surface of the pore openings, causing blockage of the airflow channels. The average blockage area on the bottom end face exceeds 40%.

[0160] In Example 2, the pressure drop curve, after experiencing the pressure fluctuations during the pulse, returned to and stabilized near the initial baseline (approximately 190 Pa), with the pressure drop growth rate controlled within 4%. This result indicates that the graded interception structure functioned effectively: the detached hard debris fell into the cavity buffer zone after passing through the large pores in the top layer and was physically trapped by the alloy mesh. The porosity of the alloy mesh ensured that the accumulated debris did not create significant aerodynamic resistance, while simultaneously blocking the path of debris into the microporous region of the bottom layer. This test verified that this scheme can avoid the secondary clogging problem caused by debris falling during traditional RTO online cleaning, ensuring the hydraulic stability of the system.

Claims

1. A regenerative thermal incinerator waste gas treatment material resistant to silicon blockage, characterized in that, The material is a honeycomb ceramic made from a dry powder mixture containing the following raw materials in the following weight percentages, through kneading, extrusion molding, and sintering: Kaolin: 38.0%–41.5%; Talc: 36.0%~38.0%; Calcined alumina: 14.0%–16.0%; Magnesium-stabilized aluminum titanate clinker: 4.0%–6.0%; Monoclinic zirconium oxide: 2.0%–3.0%; Lithium feldspar: 0.5%–1.0%; The sum of the weight percentages of all components is 100%; The magnesium-stabilized aluminum titanate clinker is a powder synthesized in advance from alumina, titanium dioxide, magnesium oxide and iron oxide red through a high-temperature solid-phase reaction.

2. The regenerative thermal incinerator waste gas treatment material with anti-silicon blockage as described in claim 1, characterized in that, The magnesium-stabilized aluminum titanate clinker is made from an initial raw material comprising the following molar ratio: α-alumina powder: rutile titanium dioxide: light magnesium oxide: iron oxide red = 1.0:(0.85~0.95):(0.05~0.15):(0.02~0.05).

3. The regenerative thermal incinerator waste gas treatment material with anti-silicon blockage according to claim 2, characterized in that, The preparation process of the magnesium-stabilized aluminum titanate clinker includes: The initial raw materials are placed in a ball mill jar, and deionized water is added as the medium for ball milling and mixing for 12 to 16 hours to obtain a mixed slurry. The mixed slurry is spray-dried, granulated, and pressed to obtain green blocks; The green block is placed in a high-temperature kiln, heated to 1480℃~1520℃ and held for 6~8 hours to carry out a solid-phase synthesis reaction to obtain synthesized clinker. The synthesized clinker was subjected to mechanical crushing, ball milling and air classification to obtain magnesium-stabilized aluminum titanate clinker with a particle size distribution D50 of 5.0 μm to 8.0 μm.

4. The regenerative thermal incinerator waste gas treatment material with anti-silicon blockage according to claim 1, characterized in that, The material is a honeycomb ceramic structure with a pore density of 10–13 cpsi and a wall thickness of 1.4 mm–1.6 mm.

5. A method for preparing regenerative thermal incinerator waste gas treatment materials resistant to silicon blockage, characterized in that, The preparation of the regenerative thermal incinerator exhaust gas treatment material with silicon blockage resistance as described in any one of claims 1-2 includes the following steps: Kaolin, talc, and calcined alumina were weighed according to the formula as matrix raw materials, and magnesium-stabilized aluminum titanate clinker, monoclinic zirconium oxide, and lithium feldspar were added as modifying raw materials. The above raw materials were mixed to obtain a dry powder mixture. Deionized water is added to the dry powder mixture for ball milling dispersion. After dehydration by pressure filtration, mud cake is obtained. Organic additives are added to the mud cake, and the mixture is aged and kneaded in a vacuum plow to obtain plastic mud segments. The plastic clay segment is extruded and shaped using an extrusion die, and after drying, a honeycomb ceramic green body is obtained. The honeycomb ceramic green body is placed in a tunnel kiln for sintering. After sintering, it is cooled to 1100°C with the furnace. Then, a fan is turned on in the range of 1100°C to 700°C for rapid cooling and shaping. Finally, it is cooled to room temperature to obtain the silicon-resistant regenerative thermal incinerator waste gas treatment material.

6. The preparation method of the regenerative thermal incinerator waste gas treatment material against silicon blockage according to claim 5, characterized in that, In the step of sintering the honeycomb ceramic green body, the specific process parameters are: heating to 1390℃~1410℃ and holding for 5~6 hours.

7. The preparation method of the regenerative thermal incinerator waste gas treatment material with silicon blockage resistance according to claim 5, characterized in that, In the rapid cooling and shaping step, the cooling rate is controlled to be 5℃ / min to 8℃ / min.

8. The preparation method of the regenerative thermal incinerator waste gas treatment material against silicon blockage according to claim 5, characterized in that, In the step of preparing the plastic mud segment, the organic additives include 4.0% to 4.5% hydroxypropyl methylcellulose and 2.0% to 2.5% glycerol relative to the weight of the mud cake.

9. The preparation method of the anti-silicon blockage regenerative thermal incinerator waste gas treatment material according to claim 5, characterized in that, In the step of preparing the honeycomb ceramic green body, the drying treatment includes microwave drying and hot air drying, and the moisture content of the honeycomb ceramic green body is controlled to be less than 1%.

10. The method for preparing the anti-silicon blockage regenerative thermal incinerator waste gas treatment material according to claim 5, characterized in that, In the step of preparing the mud cake, the moisture content of the mud cake is controlled to be 22% to 24%.

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