Method for judging quality of fat coal by using small coke oven blending method

Abstract

The application discloses a method for judging fat coal quality by using a small coke oven coal blending method, which takes coke powder recovered by gravity dust removal of a dry quenching furnace as basic coal blending, and is blended with fat coal to be measured, so that the quality of the fat coal is judged by comparing the thermal reactivity and thermal intensity of the coke after coking. The coke powder collected by gravity dust removal of the dry quenching process is selected as the basic coal blending, so that the problems of unstable consistency of the coal quality of the basic coal blending used for judging the fat coal, easy oxidation and metamorphism of long-term storage and the like can be effectively solved, and the judgment result is accurate and reliable.

Description

Technical Field

[0001] This invention belongs to the field of coal blending technology, specifically relating to a method for judging the quality of coking coal using a small coke oven coal blending method. Background Technology

[0002] In the field of coking coal blending, to determine the quality of coking coal, and addressing the pain point of small differences in thermal intensity between single coking coals from different mines and small coke ovens, resulting in indistinct performance differentiation after blending, a common experimental logic is to use a fixed basic coal blending scheme plus an equal amount of the coking coal to be tested. This approach amplifies the differences in caking and plasticity of coking coals from different mines by using the thermal intensity index of the coke produced after blending, thus achieving accurate quality determination. The basic coal blending scheme typically selects a combination of lean coal, coking coal, and gas coal with stable performance and moderate caking. However, since the amount of coal required for a single small coke oven test is usually over 40 kg, even with a 50% fixed basic coal blending scheme, the required basic coal amount is at least 10-20 kg per test. To ensure the stability of the basic coal blend, a large quantity of basic coal is usually prepared at once for subsequent tests. However, if the prepared basic coal is stored for more than 3 months, there is a risk of oxidation and deterioration, which will affect the accuracy of the results. Therefore, it is necessary to develop a basic coal blend with a stable source or that can be stored for a long time to ensure the stability of the test results, thereby achieving accurate quality determination of coking coal. Summary of the Invention

[0003] To address the problems of unstable coal quality consistency and easy oxidation and deterioration during long-term storage in the basic coal blending used for judging fat coal, this invention provides a new method for judging the quality of fat coal using small coke oven coal blending.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for determining the quality of coking coal using a small coke oven blending method involves using coke powder recovered from gravity dust removal in a dry quenching furnace as the base blending material, blending it with the coking coal to be tested, and determining the quality of the coking coal by comparing the thermal reactivity and thermal strength of the coke after coking.

[0005] This invention selects coke powder collected during the primary dust removal process (gravity dust removal) in the dry quenching furnace as the base coal blend. After high-temperature coking, its properties are stable and it will not oxidize or deteriorate during long-term storage. Furthermore, the coke powder originates from production and can be obtained in large quantities at once or in multiple batches. In addition, although the composition of blended coal may change at different times, the main carbon element in the coke powder after high-temperature coking generally reaches over 85%, and the volatile matter is 0.8%~3.0%, exhibiting uniform and stable properties that ensure the consistency of coal quality.

[0006] Furthermore, the mass ratio of coke powder to coking coal used is 25:75.

[0007] The ratio of base coal to the tested coking coal is also a factor affecting accuracy. If the proportion of the tested coking coal is too high, the scale-up effect is not obvious; if the proportion is too low, the differences in cold strength, hot strength, and other indicators of the coke after coking are small.

[0008] Furthermore, the particle size of the coke powder is 0.5~3mm, wherein the particle size of 0.5~1mm and the particle size of 1~3mm each account for 50wt%.

[0009] In the dust removal process of dry quenching furnace, the proportion of coke powder with a particle size of less than 3mm in the primary dust removal process is generally 90% to 94%. Coke powder with a particle size of 0.5 to 3mm is selected as the basic coal blending material (of which 0.5 to 1mm and 1 to 3mm each account for 50%), and coke powder of other particle sizes can be sent back to the coke powder system.

[0010] Furthermore, the moisture content of the coking coal is 8-13 wt%.

[0011] The coking coal used in this invention is washed coal with a moisture content of 8-13 wt%. Since coke powder can absorb a small amount of moisture, there is no need to add water to the coke powder during the coal blending process, which simplifies the process steps.

[0012] The significant advantages of this invention are: (1) This invention relies on the dry quenching process and selects coke powder collected by gravity dust removal as the basic coal blending. It has stable properties, can be stored for a long time, and its particle size meets the coal blending requirements. It can also ensure that the benchmark of the test is consistent at different times.

[0013] (2) The coal blending method used in this invention can greatly amplify the differences in the caking and plasticity of coking coal, and its discrimination results are accurate and reliable. It solves the problem that the difference in thermal intensity is small and cannot be accurately judged after coking in a small coke oven with single coking coal.

[0014] (3) This invention does not require any new testing equipment. It can determine the quality of coking coal by relying on existing small coke ovens and heat intensity testing equipment. It is simple to operate and the data is easy to compare. It can be directly used for screening and procurement quality control of coking coal mines. Detailed Implementation

[0015] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto. Example

[0016] (1) Preparation of basic coal blend: collect coke powder (its particle size distribution is shown in Table 1) from the triple sleeve of the gravity dust collector of the dry quenching furnace; mix coke powder with a particle size of 0.5~1mm and 1~3mm in a 50% ratio as basic coal blend, and send coke powder of other particle sizes back to the coke powder system.

[0017] Table 1

[0018] (2) Determination of the ratio of basic coal blending to the coking coal to be tested: Coking coal A (Shanxi region coking coal Vdaf 28.5~31.3%) collected from the same mine site and batch was crushed in a crusher and screened with a 3mm round hole screen. The material on the screen was further crushed to below 3mm. Then, the screened crushed coking coal was thoroughly mixed with the basic coal blending according to different ratios, spread out indoors, and air-dried naturally for 8 hours. Then, 40kg of mixed coal sample was taken, loaded into a small coke oven, and compacted with an iron plate (ensuring a coal loading height of 540mm and a bulk density of 0.78~0.8t / m³). 3 The temperature was raised to 1050℃ according to the small coke oven heating curve and kept at a constant temperature for 5 hours for coking. After coking, the coke was naturally cooled under sealed conditions, and then the post-reaction strength (CSR) and coke reactivity (CSR) were tested according to national standards. The results are shown in Table 2.

[0019] Table 2

[0020] As shown in Table 2, in a blend of 50% coking coal and 50% coke powder, the corresponding indicators cannot be detected because the hot structure of the coke is completely disintegrated, thus failing to reflect the quality differences between different coking coals. A blend of 75% coking coal and 25% coke powder is close to the critical point of inertness, and its binding capacity is at a sensitive critical state. Differences in the binding properties of coking coals are significantly amplified, and the CSR of 2.4% helps ensure that the data meets the precision requirements (CSR repeatability r ≤ 3.2%) in the national standard "Test Method for Reactivity and Post-Reaction Strength of Coke". However, when the proportion of coking coal is ≥ 80%, its CSR is at a high level, compressing the numerical differences and failing to reflect the quality differences between different coking coals. Therefore, a blend of 75% coking coal and 25% coke powder is selected as the optimal blend for judging the quality of coking coal.

[0021] (3) Sample determination According to the proportion determined in step (2), the coking coals B, C, and D (Vdaf 28~35%) collected from different mines were mixed with the basic blended coal for small coke oven tests, and the quality of different coking coals was judged based on coking coal A. The results are shown in Table 3.

[0022] Table 3

[0023] As shown in Table 3, the results of testing with coking coal from different mining sites showed significant differences, proving that this method has a strong ability to distinguish the quality of coking coal.

[0024] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for determining the quality of coking coal using a small coke oven blending method, characterized in that, Coke powder recovered by gravity dust removal in a dry quenching furnace is used as the base coal blending and blended with the coking coal to be tested. The quality of the coking coal is determined by comparing the thermal reactivity and thermal strength of the coke after coking.

2. The method for determining the quality of coking coal using the small coke oven coal blending method according to claim 1, characterized in that, The mass ratio of coke powder to coking coal used is 25:

75.

3. The method for determining the quality of coking coal using the small coke oven blending method according to claim 1, characterized in that, The coke powder has a particle size of 0.5~3mm, wherein the particle size of 0.5~1mm and the particle size of 1~3mm each account for 50wt%.

4. The method for determining the quality of coking coal using the small coke oven coal blending method according to claim 1, characterized in that, The moisture content of the coking coal is 8-13 wt%.

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