Combustion-supporting composite material resistant to high-temperature oxidation and method for stable combustion of water vapor

Abstract

This invention discloses a high-temperature oxidation-resistant combustion-supporting synthetic material and a method for stable combustion in water vapor. The invention relates to the field of energy and combustion technology. The material comprises the following components by weight: 40-60 parts magnesium oxide (MgO); 40-60 parts aluminum oxide (Al2O3); 20-40 parts silicon carbide (SiC); 10-20 parts chromium trioxide (Cr2O3); and 10-20 parts zirconium dioxide (ZrO2). The combustion-supporting synthetic material is prepared by uniform mixing and firing. By using a high-temperature stable ceramic composite with specific components as the combustion-supporting medium and constructing a working method including dual-threshold temperature control, the defects of existing technologies are effectively overcome. This fundamentally eliminates the problem of rapid oxidation and pulverization of refractory alloys in high-temperature water vapor environments, avoids the generation and emission of heavy metal oxide fumes at the source, and significantly reduces environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of energy and combustion technology, specifically to a high-temperature oxidation-resistant combustion-supporting synthetic material and a method for stable combustion of water vapor. Background Technology

[0002] Steam combustion technology refers to the process of bringing steam into contact with a specific catalyst or high-temperature medium under high-temperature conditions, causing it to decompose and react with fuel or itself in an oxidation reaction, releasing heat energy. Theoretically, this technology can utilize steam as a reactant or combustion-supporting medium to improve fuel utilization efficiency or achieve special combustion conditions.

[0003] However, existing steam combustion technology suffers from several key technical defects that severely restrict its practical application and safety: First, existing technologies typically rely on refractory metals such as tungsten and rhenium, or their alloys, as high-temperature reaction media. These materials undergo severe oxidation and corrosion at extreme operating temperatures exceeding 1500°C and in oxidizing steam atmospheres, generating volatile or dust-like heavy metal oxides (such as tungsten trioxide and rhenium heptaoxide). This not only leads to rapid depletion and functional failure of the reaction media itself but also causes severe heavy metal dust emission pollution. Second, to achieve the decomposition and combustion of steam, existing technologies require heating the alloy medium to ultra-high temperatures exceeding 1500°C. This temperature approaches or exceeds the melting point limits of materials used in conventional boiler combustion chamber structural components (especially welded joints of pressure-bearing parts), posing a fatal safety risk of weld meltdown, equipment rupture, or even explosion.

[0004] Furthermore, existing technology is extremely sensitive to the temperature of steam entering the furnace. When the temperature of the steam introduced is low (e.g., below 300°C), it cannot stably maintain the combustion reaction after contacting the high-temperature medium, which can easily lead to reaction interruption, violent fluctuations in firepower, or even complete flameout, making the system operation extremely unstable.

[0005] To address these technical problems, a combustion-supporting synthetic material resistant to high-temperature oxidation and a method for stable combustion with water vapor were designed. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a combustion-supporting synthetic material resistant to high-temperature oxidation and a method for stable combustion of water vapor, thus solving the technical problems mentioned in the background section.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: a high-temperature oxidation-resistant synthetic material, comprising the following components by weight: magnesium oxide (MgO) 40-60 parts; aluminum oxide (Al2O3) 40-60 parts; silicon carbide (SiC) 20-40 parts; chromium trioxide (Cr2O3) 10-20 parts; zirconium dioxide (ZrO2) 10-20 parts; the combustion-supporting synthetic material is prepared by uniform mixing and firing.

[0008] Preferably, the combustion-supporting synthetic material is placed in the reaction zone of the boiler combustion chamber as a catalytic and heat storage medium for steam decomposition and combustion.

[0009] Preferably, it includes the following steps: S1. Place the combustion-supporting synthetic material in the boiler combustion chamber; S2. Start the boiler and use carbon-containing fuel to heat the combustion-supporting synthetic material to an operating temperature of 1000℃-1100℃; S3. Preheat the steam to 300℃-500℃ using a steam superheater; S4. The preheated high-temperature steam is introduced into the combustion-supporting synthetic material area that has reached the working temperature, so that the steam can burn fully and stably.

[0010] Preferably, the method further includes a temperature safety control step: an intelligent exhaust fan is installed at the boiler flue outlet, and a first temperature threshold T1 and a second temperature threshold T2 are set, wherein T1 > T2; when the boiler combustion chamber temperature is detected to reach or exceed the first temperature threshold T1, the intelligent exhaust fan is started to accelerate the discharge of high-temperature flue gas so that the combustion chamber can be cooled down rapidly; when the combustion chamber temperature drops to the second temperature threshold T2 or below, the intelligent exhaust fan is stopped.

[0011] Preferably, the first temperature threshold T1 is set to 1250℃, and the second temperature threshold T2 is set to a range of 1000℃-1100℃.

[0012] A boiler system for achieving stable combustion of steam, the system comprising: a boiler combustion chamber, wherein the high-temperature oxidation-resistant combustion-aiding synthetic material as described in claim 1 is disposed inside; a steam superheater, the inlet of which is connected to the boiler steam generation equipment, and the outlet of which is connected to the high-temperature steam inlet of the boiler combustion chamber via a pipeline, for heating steam to 300-500℃; and an intelligent exhaust fan installed on the flue at the boiler chimney outlet, the intelligent exhaust fan being signal-connected to a temperature sensor installed in the boiler combustion chamber, for performing start-up and shutdown operations according to the combustion chamber temperature.

[0013] Preferably, the intelligent exhaust fan is configured to start when the temperature sensor detects that the combustion chamber temperature reaches 1250°C, and stop when the temperature drops to 1000°C-1100°C.

[0014] Preferably, the melting point of the welding structural material of the boiler combustion chamber is below 1300°C.

[0015] Beneficial effects This invention provides a high-temperature oxidation-resistant combustion-supporting synthetic material and a method for stable steam combustion. By employing a high-temperature stable ceramic composite with specific components as the combustion-supporting medium and constructing a working method incorporating dual-threshold temperature control, this invention effectively overcomes the shortcomings of existing technologies. Specifically: 1. It fundamentally eliminates the problem of rapid oxidation and pulverization of refractory alloys in high-temperature steam environments, preventing the generation and emission of heavy metal oxides and dust at the source, significantly reducing environmental pollution. 2. By setting the core operating temperature within a low and safe range and introducing an active overheat protection mechanism, it completely avoids the major safety hazard of melting at critical boiler connection points due to overheating. 3. By using preheated steam at a suitable temperature to react with the stable high-temperature material surface, it ensures the continuity and stability of the steam decomposition and combustion process, overcoming the problems of intermittent combustion and large fluctuations in firepower in traditional technologies. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a high-temperature oxidation-resistant combustion-supporting synthetic material and a method for stable combustion of water vapor as described in this invention.

[0017] In the diagram: 1. Boiler flue; 2. Intelligent exhaust fan; 3. Steam heater; 4. Steam inlet; 5. Steam superheater; 6. Steam distribution cylinder; 7. Production steam; 8. Boiler combustion chamber; 9. Antioxidant synthetic material; 10. Air inlet; 11. Carbon fuel inlet; 12. High-temperature steam inlet. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0019] Please see Figure 1The present invention provides a technical solution: a high-temperature oxidation resistant synthetic material, comprising the following components by weight: 40-60 parts of magnesium oxide (MgO); 40-60 parts of aluminum oxide (Al2O3); 20-40 parts of silicon carbide (SiC); 10-20 parts of chromium trioxide (Cr2O3); and 10-20 parts of zirconium dioxide (ZrO2); the combustion-supporting synthetic material is prepared by uniform mixing and firing.

[0020] In this embodiment, the combustion-supporting synthetic material is placed in the reaction zone of the boiler combustion chamber as a catalytic and heat storage medium for steam decomposition and combustion.

[0021] This embodiment is further configured to include the following steps: S1. Place the combustion-supporting synthetic material in the boiler combustion chamber; S2. Start the boiler and use carbon-containing fuel to heat the combustion-supporting synthetic material to an operating temperature of 1000℃-1100℃; S3. Preheat the steam to 300℃-500℃ using a steam superheater; S4. The preheated high-temperature steam is introduced into the combustion-supporting synthetic material area that has reached the working temperature, so that the steam can burn fully and stably.

[0022] This embodiment is further configured to include a temperature safety control step: an intelligent exhaust fan is installed at the boiler flue outlet, and a first temperature threshold T1 and a second temperature threshold T2 are set, wherein T1 > T2; when the boiler combustion chamber temperature is detected to reach or exceed the first temperature threshold T1, the intelligent exhaust fan is started to accelerate the discharge of high-temperature flue gas so that the combustion chamber can be cooled down rapidly; when the combustion chamber temperature drops to the second temperature threshold T2 or below, the intelligent exhaust fan is stopped.

[0023] In this embodiment, the first temperature threshold T1 is set to 1250℃, and the second temperature threshold T2 is set to a range of 1000℃-1100℃.

[0024] A boiler system for achieving stable combustion of steam, the system comprising: a boiler combustion chamber, wherein the high-temperature oxidation-resistant combustion-aiding synthetic material as described in claim 1 is disposed inside; a steam superheater, the inlet of which is connected to the boiler steam generation equipment, and the outlet of which is connected to the high-temperature steam inlet of the boiler combustion chamber via a pipeline, for heating steam to 300-500℃; and an intelligent exhaust fan installed on the flue at the boiler chimney outlet, the intelligent exhaust fan being signal-connected to a temperature sensor installed in the boiler combustion chamber, for performing start-up and shutdown operations according to the combustion chamber temperature.

[0025] In this embodiment, the intelligent exhaust fan is configured to start when the temperature sensor detects that the combustion chamber temperature reaches 1250°C, and stop when the temperature drops to 1000°C-1100°C.

[0026] In this embodiment, the welding structural material of the boiler combustion chamber has a melting point below 1300°C.

[0027] Its detailed connection method is a well-known technology in this field. The following mainly introduces the working principle and process, and the specific work is as follows.

[0028] Example: Implementation and Application Effects of the Steam Stabilized Combustion Method I. Preparation of Combustion-Assisting Synthetic Materials Ingredients: Accurately weigh the following high-purity raw materials (all parts by weight): Magnesium oxide (MgO, ≥99.0%) 50 parts Aluminum oxide (Al2O3, ≥99.5%) 50 parts Silicon carbide (SiC, ≥98.5%) 30 parts Chromium trioxide (Cr2O3, ≥99.0%) 15 parts Zirconium dioxide (ZrO2, ≥99.0%) 15 parts Mixing: Place the above powder raw materials in a high-efficiency three-dimensional mixer and mix continuously for 4 hours until the components are evenly distributed.

[0029] Forming and firing: The uniformly mixed powder is pressed into a cylindrical blank with a diameter of 20 mm and a height of 10 mm. The blank is placed in a high-temperature atmosphere sintering furnace, and heated to 1950°C at a rate of 5°C / min under an argon protective atmosphere, and held at this temperature for 3 hours, and then naturally cooled to room temperature with the furnace.

[0030] Finished product: The resulting synthetic material has a dense structure and is grayish-black in color. Its bulk density is ≥3.2 g / cm³. 3 The material exhibits a room temperature compressive strength ≥150 MPa. It is named "HT-OxR" and will be used in subsequent combustion experiments.

[0031] II. Combustion System Setup and Comparative Tests Experimental Setup: A small vertical experimental boiler was constructed. The combustion chamber was lined with refractory brick grating to support the combustion-supporting materials. High-temperature steam nozzles were installed on the side wall of the combustion chamber, and high-precision K-type thermocouples (temperature range 0-1300℃) were installed to monitor the reaction zone temperature in real time. A PLC-controlled variable frequency exhaust fan was installed at the boiler flue outlet. Steam was supplied by an electrically heated superheater, with the temperature precisely adjustable between 100-600℃.

[0032] Experimental Groups: Control group: An equal volume of conventional tungsten-rhenium alloy (W-5%Re) fragments were filled onto the combustion chamber grille as a combustion aid.

[0033] Experimental group: The combustion chamber grid was filled with an equal volume of the "HT-OxR" synthetic material block prepared in this invention.

[0034] Experimental Methods (Focusing on verifying the steps of this method): a. Initial Heating Stage: Both groups of experiments used natural gas as the initial fuel, with air introduced to assist combustion, heating their respective combustion media (alloy or HT-OxR material). b. Steady-State Combustion and Temperature Control Stage (Core of this Method): For the experimental group (HT-OxR material): The temperature was stabilized at 1050℃. At this time, the temperature of the steam generated by the electric superheater was set to 400℃, and then it was introduced into the combustion chamber. Combustion occurred rapidly and remained stable. Safety Control Simulation: The natural gas supply was artificially increased to raise the combustion chamber temperature. When the thermocouple detected that the temperature reached the preset 1250℃ (first threshold), the PLC immediately started the variable frequency exhaust fan at the flue outlet to the highest speed, forcibly exhausting the high-temperature flue gas. The combustion chamber temperature rapidly dropped from 1250℃ to approximately 1030℃ (below the second threshold of 1050℃) within 2 minutes, at which point the PLC controlled the exhaust fan to stop. Throughout the entire process, the welding point of the combustion chamber (simulated melting point 1510℃) remained safe. c. Comparative operation with the control group: In order for water vapor to burn, the traditional technique requires heating the tungsten-rhenium alloy to above 1550℃. We heated it to 1580℃ and then introduced water vapor at the same temperature of 400℃, and combustion occurred.

[0035] III. Experimental Results and Analysis Comparison of material stability and pollution: Experimental group (HT-OxR material): After 120 hours of continuous operation, the machine was stopped for inspection. The HT-OxR material block was intact, without cracks or pulverization, and the surface was only slightly darker in color, with a mass loss rate of only 0.3%. XRD analysis of flue dust showed no characteristic peaks of heavy metal oxides.

[0036] Control group (tungsten-rhenium alloy): Severe oxidation and peeling were observed on the alloy surface after 24 hours of operation. After 120 hours of operation, the alloy volume decreased significantly, forming a large amount of green (Re2O7 volatiles condensation) and yellow (WO3) powder. The material mass loss rate reached 18.5%. Flue dust analysis showed that it contained a large amount of WO3 and Re2O7.

[0037] Comparison of combustion stability: Experimental group: At a working temperature of 1050℃, when water vapor at 300-500℃ is introduced, the flame appears bright light blue, the combustion is very stable, and the heat flow fluctuation range is less than ±5%.

[0038] Control group: At a high temperature of 1580℃, combustion was acceptable in the initial stage, but as the alloy oxidized and was depleted, the catalytic activity decreased, the flame gradually weakened and flickered, and the heat flow fluctuated by more than ±30%. When the temperature of water vapor was reduced to 250℃, the combustion reaction immediately stopped and the flame went out, proving that the existing technology is sensitive to steam temperature and unstable.

[0039] Security Comparison: Experimental group: The working temperature (1050℃) is far lower than the softening point of conventional boiler steel and welding materials. Combined with the over-temperature protection of the intelligent exhaust fan, the risk of melting is fundamentally eliminated.

[0040] Control group: The required operating temperature of 1580℃ is higher than the structural limits of most boilers, posing a significant structural safety hazard.

[0041] Conclusion: This embodiment fully demonstrates that by using the high-temperature oxidation-resistant combustion-supporting synthetic material with a specific composition provided by this invention, and following the method of "heating the material to 1000-1100℃ and then introducing 300-500℃ steam", combined with the safety strategy of "intelligent ventilation and cooling based on a 1250℃ threshold", the three fatal drawbacks of traditional alloy combustion-supporting technologies can be solved simultaneously and effectively: material oxidation pollution, unstable combustion process, and high-temperature safety risks. This achieves safe, stable, and clean operation of steam combustion technology.

[0042] It should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

Claims

1. A synthetic material resistant to high-temperature oxidation, characterized in that, The following components are included in parts by weight: Magnesium oxide (MgO) 40-60 parts; Aluminum oxide (Al2O3) 40-60 parts; Silicon carbide (SiC) 20-40 parts; Chromium trioxide (Cr2O3) 10-20 parts; Zirconium dioxide (ZrO2) 10-20 parts; The combustion-supporting synthetic material is produced by mixing it evenly and then firing it.

2. The application of the high-temperature oxidation-resistant combustion-promoting synthetic material as described in claim 1 in promoting steam combustion, characterized in that, The combustion-supporting synthetic material is placed in the reaction zone of the boiler combustion chamber as a catalytic and heat storage medium for steam decomposition and combustion.

3. A method for achieving stable combustion of water vapor using the combustion-supporting synthetic material described in claim 1, characterized in that, Includes the following steps: S1. Place the combustion-supporting synthetic material in the boiler combustion chamber; S2. Start the boiler and use carbon-containing fuel to heat the combustion-supporting synthetic material to an operating temperature of 1000℃-1100℃; S3. Preheat the steam to 300℃-500℃ using a steam superheater; S4. The preheated high-temperature steam is introduced into the combustion-supporting synthetic material area that has reached the working temperature, so that the steam can burn fully and stably.

4. The method according to claim 3, characterized in that, It also includes temperature safety control steps: an intelligent exhaust fan is installed at the boiler flue outlet, and a first temperature threshold T1 and a second temperature threshold T2 are set, where T1 > T2; when the boiler combustion chamber temperature is detected to reach or exceed the first temperature threshold T1, the intelligent exhaust fan is started to accelerate the discharge of high-temperature flue gas so that the combustion chamber can be cooled down rapidly; when the combustion chamber temperature drops to the second temperature threshold T2 or below, the intelligent exhaust fan is stopped.

5. The method according to claim 4, characterized in that, The first temperature threshold T1 is set to 1250℃, and the second temperature threshold T2 is set to a range of 1000℃-1100℃.

6. A boiler system for achieving stable combustion of steam, characterized in that, The system includes: The boiler combustion chamber is equipped with the high-temperature oxidation-resistant combustion-aiding synthetic material as described in claim 1. A steam superheater, whose inlet is connected to the boiler steam generation equipment and whose outlet is connected to the high-temperature steam inlet of the boiler combustion chamber through a pipeline, is used to heat steam to 300-500℃; An intelligent exhaust fan is installed on the flue at the boiler chimney outlet. The intelligent exhaust fan is connected to a temperature sensor located in the boiler combustion chamber and is used to perform start-up and shutdown operations based on the combustion chamber temperature.

7. The boiler system according to claim 6, characterized in that, The intelligent exhaust fan is configured to start when the temperature sensor detects that the combustion chamber temperature reaches 1250°C, and stop when the temperature drops to 1000°C-1100°C.

8. The boiler system according to claim 6 or 7, characterized in that, The melting point of the welding structure material of the boiler combustion chamber is below 1300℃.

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