Coal sample anti-oxidation method for small coke oven experiment

Abstract

The invention discloses a coal sample anti-oxidation method for a small coke oven experiment, and belongs to the technical field of steelmaking. The method comprises the following steps: loading a quantitative coal sample into a coal box, and striking off the upper surface of the coal sample; laying a fire-resistant heat-insulating fiber layer on the upper surface of the coal sample to cover the coal sample and contact with the edge of the inner wall of the coal box so as to isolate the coal sample from the furnace top space and prevent the coal sample from being oxidized and polluted by volatile matters; closing a coal box cover, and feeding the coal box into a preheated small coke oven for coking; and after coking is finished, pushing out the coal box, moving away the fire-resistant heat-insulating fiber layer, and taking out a coke sample for analysis. Wherein the fire-resistant heat insulation fiber layer is ceramic fiber cotton, is positioned on the upper surface of a coal sample, reduces heat loss through a heat insulation effect, ensures uniform maturity of a coke cake, captures volatile matters through an adsorption effect, and prevents a furnace body from being polluted. The method is simple and convenient to operate, can effectively inhibit coal sample oxidation, reduces equipment pollution, stabilizes a thermal field, and ensures uniform quality of coke samples and accurate experimental data.

Description

Technical Field

[0001] This invention relates to the field of steelmaking technology, and more specifically to a method for preventing oxidation of coal samples used in small coke oven experiments. Background Technology

[0002] Small coke oven experiments are a core technical means to simulate industrial coking production, evaluate the coking performance of coking coal, and optimize coal blending schemes. The experimental results are of crucial guiding significance for actual production, controlling coke quality, and reducing production costs. In existing conventional small coke oven experimental techniques, the operating procedure is as follows: a fixed amount of coal sample (e.g., 40 kg) is directly loaded into the coal box of the coke oven, and then the entire coal box is pushed into the coke oven, which has been preheated to the target temperature. High-temperature dry distillation (i.e., coking) is then carried out under air-isolated conditions, ultimately obtaining a coke sample for analysis of various indicators. Due to minute gaps in the experimental equipment, or air that is difficult to completely remove during the initial loading stage, trace amounts of oxygen may remain in the space above the coal box. When the coal sample is directly exposed to this environment, its surface (especially highly reactive coal particles) will undergo localized combustion or oxidation reactions with the oxygen. This oxidation reaction not only consumes the effective components in the coal sample but also generates additional heat and gas, leading to instability in the coke formation process and affecting the accuracy of the final physical and chemical properties of the coke. For example, oxidation may lead to reduced coke strength, increased ash content, or deviations in coking rate, thereby misleading the optimization of coal blending schemes.

[0003] During coking, the upper surface of the coal sample is directly exposed to the furnace roof space, making it one of the main heat loss surfaces. Due to the large furnace roof space and the existence of temperature gradients, the heat loss rate on the upper surface is much higher than that of the interior and lower part of the coal sample, resulting in inconsistent maturity of the coke cake. Specifically, the upper part of the coal sample may not coke sufficiently due to insufficient heat, while the lower part may be overheated and over-carbonized. This inhomogeneity is directly reflected in the test results of coke drum strength, reactivity, etc., further amplifying the error in the experimental data. At the same time, uneven volatile matter release channels will cause local airflow velocity and pressure fluctuations in the furnace. These fluctuations may originate from local temperature differences caused by the direct exposure of the upper surface of the coal sample, leading to uneven release of volatiles, which in turn forms turbulence or pressure gradients in the furnace, affecting the overall thermal field stability. During the dry distillation of coal, viscous coal tar and bitumen are released. These high-temperature volatiles rise directly and condense on the relatively cooler inner walls of the furnace roof and pipes. This condensation not only clogs pipes and affects gas flow within the furnace, but also causes equipment corrosion and contamination, increasing maintenance costs and the risk of experimental interruptions. Long-term accumulation of tar condensate also reduces the furnace's thermal efficiency because these contaminants hinder heat radiation and convection, leading to prolonged preheating times or inaccurate temperature control. In existing technologies, these problems are summarized into three core technical bottlenecks: coal sample oxidation, equipment contamination, and unstable thermal field. These bottlenecks directly restrict the reliability and repeatability of small coke oven experiments. For example, in actual operation, coal sample oxidation can lead to experimental data deviations of over 5%, equipment contamination requires frequent cleaning, and unstable thermal field necessitates manual parameter adjustments by the operator, increasing human error. Summary of the Invention

[0004] In view of this, the purpose of this invention is to solve the above problems and provide a method for preventing oxidation of coal samples in small coke oven experiments. By laying a refractory and heat-insulating fiber layer on the upper surface of the coal sample before sending the coal box into the furnace for coking, the contact between the coal sample and the high-temperature gas at the top of the furnace can be effectively isolated, preventing oxidation and burn-off of the coal sample surface, ensuring uniform quality and accurate data of the coke sample, and preventing tar condensate from contaminating the furnace body, keeping the furnace top space clean and unobstructed.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for preventing oxidation of coal samples used in small coke oven experiments includes the following steps: A fixed amount of coal sample is loaded into a coal box, and the upper surface of the coal sample is scraped flat. A refractory and heat-insulating fiber layer is laid on the upper surface of the coal sample to cover the coal sample and contact the edge of the inner wall of the coal box, so as to isolate the coal sample from the furnace top space and prevent coal sample oxidation and volatile contamination. Close the coal box cover and send the coal box into the preheated small coke oven for coking; After coking is completed, the coal box is removed, the refractory and heat-insulating fiber layer is taken out, and coke samples are taken out for analysis.

[0006] Furthermore, the refractory and heat-insulating fiber layer is ceramic fiber cotton, located on the upper surface of the coal sample. It reduces heat loss through heat insulation, ensures uniform coke cake maturity, and captures volatiles through adsorption to prevent furnace contamination.

[0007] Furthermore, the dimensions of the refractory and heat-insulating fiber layer are determined according to the actual dimensions of the coal box, with a thickness of 20 mm and a density of 128 kg / m³.

[0008] Furthermore, the coal sample is a 40kg coking coal sample to be tested. After being loaded into the coal box, the upper surface is scraped flat to provide a flat base, which facilitates the uniform laying and tight coverage of the refractory and heat-insulating fiber layer.

[0009] Furthermore, the small coke oven is preheated to the target temperature of 1050°C, and the coking process is carried out according to the standard coking curve for 18 hours, maintaining a stable thermal field inside the furnace under the protection of the refractory and heat-insulating fiber layer.

[0010] Furthermore, the coal box is a standard 40kg small coke oven coal box.

[0011] Furthermore, the refractory and heat-insulating fiber layer is sintered during the coking process, making it easy to remove after cooling without affecting the extraction and analysis of coke samples, while maintaining the cleanliness of the furnace environment.

[0012] The beneficial effects of this invention are as follows: This invention provides a method for preventing oxidation of coal samples used in small coke oven experiments. By laying a refractory and heat-insulating fiber layer on the upper surface of the coal sample, effective protection of the coal sample surface is achieved. This fiber layer, acting as a physical barrier, is located on the upper surface of the coal sample and contacts the edge of the inner wall of the coal box. Its function is to prevent the direct contact between trace amounts of oxygen in the furnace top space and the coal sample, thereby preventing localized oxidation reactions. This isolation mechanism ensures the integrity of the chemical composition of the coal sample during the coking process, avoids the loss of active coal particles, resulting in more uniform coke formation. Various indicators, such as drum strength and coking rate, are closer to actual industrial values, improving the accuracy and reliability of experimental data.

[0013] Meanwhile, the fiber layer possesses excellent thermal insulation properties, reducing heat loss from the upper surface of the coal sample, minimizing the temperature gradient between the top and bottom of the coke cake, avoiding inconsistent maturity, thereby stabilizing the furnace thermal field, reducing airflow and pressure fluctuations, and improving the overall stability of the coking process. Regarding equipment contamination prevention, the fiber layer captures and adsorbs volatiles such as coal tar and asphaltenes precipitated during coal dry distillation. These viscous substances are intercepted by the fiber layer as they rise, preventing direct condensation on the furnace top inner wall or pipes, keeping the furnace clean, and reducing maintenance frequency and costs. After the experiment, the fiber layer can be easily removed without leaving any contaminants, further simplifying the operation process. Compared to existing technologies, this invention requires no complex equipment modifications or additional gas systems; multiple benefits can be achieved simply through installation. It is suitable for standard equipment such as conventional 40kg small coke ovens, is easy to operate, and is inexpensive.

[0014] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Detailed Implementation

[0015] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0016] Example 1 The method of this invention was implemented on a conventional 40kg small coke oven to conduct an anti-oxidation experiment on coking coal samples. The specific process is as follows: Prepare a piece of ceramic fiber cotton with a size of 500mm × 400mm (determined according to the actual size of the coal box), a thickness of 20mm, and a density of 128kg / m³ as a refractory and heat-insulating fiber layer. This fiber layer is located on the upper surface of the coal sample. It reduces heat loss through its heat insulation effect and captures volatiles through adsorption.

[0017] 40 kg of the coking coal sample to be tested was loaded into the coal box, and the upper surface was scraped flat to provide a flat base, which facilitates the uniform laying and tight coverage of the refractory and heat-insulating fiber layer.

[0018] The prepared ceramic fiber cotton is laid flat on the coal sample, covering it and contacting the edge of the inner wall of the coal box, ensuring that no coal sample is exposed, so as to isolate the coal sample from the furnace top space and prevent coal oxidation and volatile contamination.

[0019] Close the coal box cover and send the coal box into the small coke oven that has been preheated to the target temperature (e.g., 1050℃). The small coke oven is preheated to the target temperature of 1050℃. The coking process is carried out according to the standard coking curve for 18 hours. Under the protection of the refractory insulation fiber layer, the thermal field inside the furnace is kept stable.

[0020] After coking is completed, the coal box is pushed out and, after cooling, the sintered ceramic fiber cotton is carefully removed. This fiber layer is sintered during the coking process and is easy to remove after cooling, without affecting the extraction and analysis of coke samples, while maintaining the cleanliness of the furnace environment.

[0021] The coke sample was removed and analyzed, including weighing and drum strength testing.

[0022] This method is applicable to conventional 40kg small coke ovens and has been put into use as a method for preventing oxidation of coal samples in refractory and heat-insulating fiber layers.

[0023] Example 2 The method of this invention was implemented on a conventional 40kg small coke oven to conduct an anti-oxidation experiment on coking coal samples. The specific process is as follows: Prepare a piece of ceramic fiber cotton with a size of 500mm×400mm (determined according to the actual size of the coal box), a thickness of 20mm, and a density of 128kg / m³ as a refractory and heat-insulating fiber layer. This fiber layer is located on the upper surface of the coal sample. It reduces heat loss through its heat insulation effect and captures volatiles through adsorption.

[0024] 40 kg of the coking coal sample to be tested was loaded into the coal box, and the upper surface was scraped flat to provide a flat base, which facilitates the uniform laying and tight coverage of the refractory and heat-insulating fiber layer.

[0025] The prepared ceramic fiber cotton is laid flat on the coal sample, covering it and contacting the edge of the inner wall of the coal box, ensuring that no coal sample is exposed, so as to isolate the coal sample from the furnace top space and prevent coal oxidation and volatile contamination.

[0026] Close the coal box cover and send the coal box into the small coke oven that has been preheated to the target temperature (e.g., 1050℃). The small coke oven is preheated to the target temperature of 1050℃. The coking process is carried out according to the standard coking curve for 18 hours. Under the protection of the refractory insulation fiber layer, the thermal field inside the furnace is kept stable.

[0027] After coking is completed, the coal box is pushed out and, after cooling, the sintered ceramic fiber cotton is carefully removed. This fiber layer is sintered during the coking process and is easy to remove after cooling, without affecting the extraction and analysis of coke samples, while maintaining the cleanliness of the furnace environment.

[0028] The coke sample was removed and analyzed, including weighing and drum strength testing.

[0029] This method is applicable to conventional 40kg small coke ovens and has been put into use as a method for preventing oxidation of coal samples in refractory and heat-insulating fiber layers.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preventing oxidation of coal samples used in small coke oven experiments, characterized in that, Includes the following steps: A fixed amount of coal sample is loaded into a coal box, and the upper surface of the coal sample is scraped flat. A refractory and heat-insulating fiber layer is laid on the upper surface of the coal sample to cover the coal sample and contact the edge of the inner wall of the coal box, so as to isolate the coal sample from the furnace top space and prevent coal sample oxidation and volatile contamination. Close the coal box cover and send the coal box into the preheated small coke oven for coking; After coking is completed, the coal box is removed, the refractory and heat-insulating fiber layer is taken out, and coke samples are taken out for analysis.

2. The method for preventing oxidation of coal samples used in small coke oven experiments according to claim 1, characterized in that, The refractory and heat-insulating fiber layer is ceramic fiber cotton, located on the upper surface of the coal sample. It reduces heat loss through heat insulation, ensures uniform coke cake maturity, and captures volatiles through adsorption to prevent furnace contamination.

3. The method for preventing oxidation of coal samples used in small coke oven experiments according to claim 1, characterized in that, The dimensions of the refractory and heat-insulating fiber layer are determined according to the actual dimensions of the coal box, with a thickness of 20 mm and a density of 128 kg / m³.

4. The method for preventing oxidation of coal samples used in small coke oven experiments according to claim 1, characterized in that, The coal sample is a 40kg coking coal sample to be tested. After being loaded into the coal box, the upper surface is scraped flat to provide a flat base, which facilitates the uniform laying and tight coverage of the refractory and heat-insulating fiber layer.

5. The method for preventing oxidation of coal samples used in small coke oven experiments according to claim 1, characterized in that, The small coke oven is preheated to the target temperature of 1050℃, and the coking process is carried out according to the standard coking curve for 18 hours. Under the protection of the refractory and heat-insulating fiber layer, the thermal field inside the furnace is kept stable.

6. The method for preventing oxidation of coal samples used in small coke oven experiments according to claim 4, characterized in that, The coal box is a standard 40kg small coke oven coal box.

7. The method for preventing oxidation of coal samples used in small coke oven experiments according to claim 2, characterized in that, The refractory and heat-insulating fiber layer is sintered during the coking process, making it easy to remove after cooling without affecting the extraction and analysis of coke samples, while maintaining the cleanliness of the furnace environment.