Method for detecting reasonable granularity of mixed coal with different bituminous coal proportions

Abstract

The invention provides a method for detecting reasonable granularity of mixed coal with different bituminous coal proportions, which comprises the following steps: 1) differential thermal curves of mixed coal in a reference period and mixed coal to be detected are respectively obtained by adopting a differential thermal balance, and the bituminous coal proportion and / or granularity distribution of the mixed coal to be detected is different from that of the mixed coal in the reference period; and 2) comparing the differential thermal curve of the mixed coal in the reference period with the differential thermal curve of the mixed coal to be detected, and determining the reasonable granularity of the mixed coal to be detected. According to the method, the differential thermal curve obtained by the differential thermal balance is used as a combustion performance parameter, and the combustion performance of the to-be-detected mixed coal and the combustion performance of the mixed coal in the reference period are compared, so that the reasonable particle size distribution of the to-be-detected mixed coal under different bituminous coal proportions is determined. The method provided by the invention can be used for adjusting the relation between the bituminous coal mixing ratio and the pulverized coal granularity under the condition that the preparation and ejection system of the mixed pulverized coal is unchanged and the combustibility of the pulverized coal in a blast furnace is unchanged, so that the safety of a mixed coal pulverizing system is ensured, the coal pulverizing and grinding time is shortened, and the production smoothness is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blast furnace ironmaking, in particular to a detection method for reasonable particle size of mixed coal with different bituminous coal ratios. BACKGROUND

[0002] At present, blast furnace coal injection is mainly based on mixed coal injection considering safety, required calorific value, economy, etc., and the mixed coal refers to a coal kind mixed by bituminous coal and anthracite in proportion, and the safety of coal powder preparation process is judged by the volatile matter proportion of the mixed coal.

[0003] In actual production, the preparation of mixed coal powder and the safety production of the injection system are greatly related to the actual process and equipment operation conditions of the existing production implementation; in view of the present situation of the sealing property of the pulverizing system, the enterprise needs to self-regulate the mixing ratio of bituminous coal and control the volatile matter content of the mixed coal powder to ensure the safety production of the system. However, at present, there is no method for determining the quantitative relationship between the adjustment of the mixing ratio of bituminous coal and the adjustment of the particle size of the mixed coal powder under the condition that the coal powder preparation system and the injection system are unchanged and the combustion of the coal powder in the blast furnace is stable. SUMMARY

[0004] Therefore, the present application provides a detection method for reasonable particle size of mixed coal with different bituminous coal ratios, which can quantitatively adjust the relationship between the mixing ratio of bituminous coal and the particle size of coal powder under the condition that the preparation of mixed coal powder and the injection system are unchanged and the combustion of coal powder in the blast furnace is unchanged.

[0005] The present application provides a detection method for reasonable particle size of mixed coal with different bituminous coal ratios, which comprises the following steps:

[0006] 1) A differential thermal balance is used to obtain the differential thermal curves of the reference period mixed coal and the to-be-detected mixed coal, and the bituminous coal ratio and / or particle size distribution of the to-be-detected mixed coal are different from those of the reference period mixed coal;

[0007] 2) The differential thermal curves of the reference period mixed coal and the to-be-detected mixed coal are compared to determine the reasonable particle size of the to-be-detected mixed coal.

[0008] In some specific implementation manners, the differential thermal balance is a microcomputer differential thermal balance.

[0009] In some specific implementation manners, the parameters of the differential thermal balance are as follows: air atmosphere, a temperature rising rate of 15-25℃ / min, a temperature rising temperature of 700-900℃, and a holding time of 3-8 min.

[0010] In some specific implementation manners, the parameters of the differential thermal balance are as follows: air atmosphere, a temperature rising rate of 20℃ / min, a temperature rising temperature of 800℃, and a holding time of 5 min.

[0011] In some specific implementation manners, the proportion of bituminous coal in the reference period mixed coal is 40%.

[0012] In some specific implementation manners, the proportion of bituminous coal in the reference period mixed coal is 40%, and the proportion of coal particles below 200 mesh is 70%.

[0013] In some specific implementation manners, the proportion of bituminous coal in the reference period mixed coal is 40%, and the proportion of coal particles below 200 mesh is 70%.

[0014] In some specific implementation manners, the proportion of bituminous coal in the reference period mixed coal is 40%, and the proportion of coal particles below 200 mesh is 70%.

[0015] In some specific implementation manners, the proportion of bituminous coal in the reference period mixed coal is 40%, and the proportion of coal particles below 200 mesh is 70%.

[0016] In some specific implementation manners, the proportion of bituminous coal in the reference period mixed coal is 40%, and the proportion of coal particles below 200 mesh is 70%.

[0017] The application provides a detection method for reasonable particle size of mixed coal with different proportions of bituminous coal, which comprises the following steps: 1) obtaining differential thermal curves of reference period mixed coal and to-be-detected mixed coal by using a differential thermal balance, wherein the proportion of bituminous coal and / or particle size distribution of the to-be-detected mixed coal are different from those of the reference period mixed coal; and 2) comparing the differential thermal curves of the reference period mixed coal and the to-be-detected mixed coal to determine the reasonable particle size of the to-be-detected mixed coal. The application takes the differential thermal curve obtained by the differential thermal balance as a combustion performance parameter, compares the combustion performance of the to-be-detected mixed coal with that of the reference period mixed coal, and determines the reasonable particle size distribution of the to-be-detected mixed coal under different proportions of bituminous coal. The method provided by the application can adjust the relationship between the proportion of bituminous coal and the particle size of coal powder under the condition that the preparation and injection system of mixed coal powder are unchanged and the combustion performance of coal powder in the blast furnace is unchanged, thereby ensuring the safety of the mixed coal powder preparation system, shortening the coal grinding time, reducing the cost of blast furnace smelting under the premise of ensuring the combustion performance of mixed coal and efficient combustion in the blast furnace, and ensuring the smoothness of production. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The mixed coal combustion performance comparison curve provided for the embodiment 1 of the application;

[0019] Figure 2 The mixed coal combustion performance comparison curve provided for the embodiment 2 of the application;

[0020] Figure 3 The mixed coal combustion performance comparison curve provided for the embodiment 3 of the application;

[0021] Figure 4 The mixed coal combustion performance comparison curve provided for embodiment 4 of the present application. DETAILED DESCRIPTION

[0022] The present application provides a detection method for reasonable particle size of mixed coal with different bituminous coal ratios. Those skilled in the art can refer to the content herein, and appropriately improve the process parameters to achieve. The method and application of the present application have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application herein without departing from the content, spirit and scope of the present application, to realize and apply the present application technology.

[0023] The terms "comprising", "having", or "including", including the use of their grammatical synonyms, should generally be understood as open-ended and non-limiting, for example, not excluding other unrecited elements or steps, unless otherwise specifically stated or understood from the context.

[0024] It should be understood that the order of steps or the order of performing certain actions is not important as long as the present application remains operable. In addition, two or more steps or actions can be performed simultaneously.

[0025] The use of any and all examples, or exemplary language herein, for example, "such as" or "including", is intended merely to better illustrate the present application and does not pose a limitation on the scope of the present application unless a claim is recited. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the present application.

[0026] In addition, the numerical ranges and parameters used to define the present application are approximate, and the related numerical values in the specific embodiments have been presented as precisely as possible. However, any numerical value inherently contains a standard deviation due to the individual test method. Therefore, unless otherwise explicitly stated, all ranges, numbers, numerical values and percentages used in the present disclosure are modified by "about". Here, "about" generally means within plus or minus 10%, 5%, 1% or 0.5% of a particular value or range.

[0027] The present application provides a detection method for reasonable particle size of mixed coal with different bituminous coal ratios, comprising the following steps:

[0028] 1) Obtain the differential thermal curves of the reference period mixed coal and the mixed coal to be tested by using a differential thermal balance, wherein the bituminous coal ratio and / or particle size distribution of the mixed coal to be tested is different from that of the reference period mixed coal;

[0029] 2) Compare the differential thermal curves of the reference period mixed coal and the mixed coal to be tested to determine the reasonable particle size of the mixed coal to be tested.

[0030] The method provided in the application is mainly used for detecting the rationality of the particle size of the mixed coal for blast furnace injection, and the mixed coal is a mixture of bituminous coal and anthracite. In the application, the reference period mixed coal is first determined, and the combustion performance thereof is taken as a reference, and the combustion performance of the mixed coal to be detected is compared with the reference, so as to determine whether the particle size of the mixed coal to be detected is reasonable. In the application, the reference period mixed coal is the mixed coal for which the proportion of bituminous coal is to be increased or the particle size of which is to be determined, and is generally the mixed coal used in the conventional production, for example, the mixed coal in which the proportion of bituminous coal is 40%, and the like, and the person skilled in the art can determine it according to the actual production.

[0031] In some specific implementations, the proportion of bituminous coal and / or the particle size distribution of the mixed coal to be detected is different from that of the reference period mixed coal.

[0032] In the application, the differential thermal curve is taken as an index for evaluating the combustion performance of the mixed coal, and the differential thermal curve is obtained by using a differential thermal balance. In some specific implementations, the differential thermal balance is a microcomputer differential thermal balance.

[0033] Specifically, the differential thermal curve of the reference period mixed coal and the differential thermal curve of the mixed coal to be detected are obtained by using a differential thermal balance, and then the differential thermal curve of the reference period mixed coal and the differential thermal curve of the mixed coal to be detected are compared, so as to determine the reasonable particle size of the mixed coal to be detected.

[0034] Specifically, the parameters of the differential thermal balance are as follows: air atmosphere, the temperature rising rate is 15-25 ℃ / min, the temperature rising temperature is 700-900 ℃, and the holding time is 3-8 min. Preferably, the parameters of the differential thermal balance are as follows: air atmosphere, the temperature rising rate is 20 ℃ / min, the temperature rising temperature is 800 ℃, and the holding time is 5 min.

[0035] The differential thermal curve of the mixed coal to be detected is compared with the differential thermal curve of the reference period mixed coal. If the two are close to each other, it indicates that the particle size and / or the proportion of bituminous coal is not a limiting condition affecting the combustion reaction of the mixed coal. If the differential thermal curve of the mixed coal to be detected has obvious fluctuations, it means that the combustion performance thereof has changed, which indicates that the particle size affects the combustion of the mixed coal. The combustion performance of the mixed coal to be detected can be ensured by adjusting the proportion of bituminous coal or the particle size distribution, so as to ensure the safety of the pulverizing system and the smoothness of the blast furnace production. For example, when the explosiveness of the mixed coal is significantly enhanced due to the high proportion of bituminous coal, the particle size of the mixed coal can be appropriately increased to weaken the explosiveness of the pulverized coal on the basis of ensuring the combustion performance, so as to ensure the safety of the pulverizing system in the process of mixing and crushing the bituminous coal and the anthracite, and the power consumption of the pulverizing process can be reduced by shortening the crushing time of the injection coal. Alternatively, for the mixed coal with large particle size, the production cost can be reduced by increasing the proportion of bituminous coal and saving the power consumption of the pulverizing process on the basis of ensuring the combustion performance and the efficient combustion in the blast furnace.

[0036] In a typical testing process, the baseline coal mixture contains 40% bituminous coal and 70% coal particles smaller than 200 mesh; the test coal mixture contains 40% bituminous coal and 30% to 65% coal particles smaller than 200 mesh. In some specific implementations, the test coal mixture contains 40% bituminous coal and 30%, 40%, 50%, or 60% coal particles smaller than 200 mesh.

[0037] In a typical testing process, the baseline coal mixture contains 40% bituminous coal and 70% coal particles smaller than 200 mesh; the test coal mixture contains 45%–70% bituminous coal and 30%–65% coal particles smaller than 200 mesh. In some specific implementations, the test coal mixture contains 50%, 60%, or 70% bituminous coal and 30%, 40%, 50%, or 60% coal particles smaller than 200 mesh.

[0038] This application provides a method for detecting the reasonable particle size of blended coal with different bituminous coal ratios, comprising the following steps: 1) obtaining differential thermal curves of a reference period blended coal and a test blended coal using a differential thermal balance, wherein the bituminous coal ratio and / or particle size distribution of the test blended coal differs from that of the reference period blended coal; 2) comparing the differential thermal curves of the reference period blended coal and the test blended coal to determine the reasonable particle size of the test blended coal. This application uses the differential thermal curves obtained by the differential thermal balance as combustion performance parameters. By comparing the combustion performance of the test blended coal with that of the reference period blended coal, the reasonable particle size distribution under different bituminous coal ratios in the test blended coal is determined. The method provided in this application can be used to determine the relationship between the bituminous coal mixing ratio and the particle size of the coal powder, under the conditions that the preparation and injection system of the mixed pulverized coal remains unchanged and the combustibility of the pulverized coal in the blast furnace remains unchanged, thereby ensuring the safety of the blended coal pulverizing system, shortening the pulverizing and grinding time, reducing the cost of blast furnace smelting while ensuring the combustion performance of the blended coal and efficient combustion in the blast furnace, and ensuring smooth production.

[0039] The present application is further illustrated below with reference to the embodiments. The scope of protection of the present application is not limited to the following embodiments.

[0040] Example 1

[0041] A baseline blend of coal with a bituminous coal ratio of 40% and 70% of the pulverized coal containing particles smaller than 200 mesh was selected. The combustion performance of the baseline blend of coal was tested using a WCT-2C differential thermal balance, specifically including the following steps:

[0042] The differential thermal test was conducted in air atmosphere, with a heating rate of 20℃ / min. The temperature was increased from 30℃ to 800℃ and held for 5 minutes before the test was completed. The differential thermal (TG) curve was plotted and analyzed using Origin software, and the obtained TG curve represents the combustion performance.

[0043] The combustion performance of blended coals with a bituminous coal ratio of 40% and particles smaller than 200 mesh comprising 60%, 50%, 40%, and 30% respectively was tested using the same method. The results are shown in [link to results]. Figure 1 , Figure 1 This is a comparison curve of the combustion performance of mixed coal provided in Example 1 of this application. Figure 1 It can be seen that under the condition of 40% bituminous coal ratio, when the proportion of coal powder particles smaller than 200 mesh decreases from 70% to 40%, the combustion performance of the mixed coal powder does not change significantly and is relatively close to that of the mixed coal powder in the baseline period. This indicates that the limiting conditions for the combustion reaction of the injected coal powder at this time are hot air temperature and oxygen enrichment rate. When the proportion of 200 mesh particles in the mixed coal powder decreases to 30%, the combustion performance of the mixed coal powder begins to decline significantly, indicating that the particle size composition of the coal powder has begun to affect the combustion reaction of the coal powder.

[0044] Example 2

[0045] A baseline blend of coal with a bituminous coal ratio of 40% and 70% of the pulverized coal containing particles smaller than 200 mesh was selected. The combustion performance of the baseline blend of coal was tested using a WCT-2C differential thermal balance, specifically including the following steps:

[0046] The differential thermal experiment was conducted in an air atmosphere with a heating rate of 20℃ / min. The temperature was increased from 30℃ to 800℃ and held for 5 minutes before the experiment ended. The TG curve was plotted and analyzed using Origin software, and the obtained TG curve represents the combustion performance.

[0047] The combustion performance of blended coals with a bituminous coal ratio of 50% and particles smaller than 200 mesh comprising 60%, 50%, 40%, and 30% respectively was tested using the same method. The results are shown in [reference needed]. Figure 2 , Figure 2 This is a comparison curve of the combustion performance of mixed coal provided in Example 2 of this application. Figure 2 It can be seen that when the bituminous coal ratio is increased to 50%, and the proportion of coal powder particles smaller than 200 mesh is 60%, 50%, and 40% respectively, the fluctuation in the combustion performance of the mixed coal powder is not significant. This indicates that the limiting conditions for the combustion reaction of the injected coal powder are hot air temperature and oxygen enrichment rate, and the limiting factor for coal powder combustion is not the specific surface area of ​​the coal powder particles. Therefore, even when the proportion of 200-mesh particles decreases to 30%, the combustion performance of the mixed coal powder decreases to some extent, but it is still significantly better than the combustion performance of the mixed coal powder in the baseline period.

[0048] Example 3

[0049] A baseline blend of coal with a bituminous coal ratio of 40% and 70% of the pulverized coal containing particles smaller than 200 mesh was selected. The combustion performance of the baseline blend of coal was tested using a WCT-2C differential thermal balance, specifically including the following steps:

[0050] The differential thermal experiment was conducted in an air atmosphere with a heating rate of 20℃ / min. The temperature was increased from 30℃ to 800℃ and held for 5 minutes before the experiment ended. The TG curve was plotted and analyzed using Origin software, and the obtained TG curve represents the combustion performance.

[0051] The combustion performance of blended coals with a bituminous coal ratio of 60% and particles smaller than 200 mesh comprising 60%, 50%, 40%, and 30% respectively was tested using the same method. The results are shown in [link to results]. Figure 3 , Figure 3 This is a comparison curve of the combustion performance of mixed coal provided in Example 3 of this application. Figure 3 It can be seen that as the proportion of bituminous coal increased to 60% and the proportion of coal powder particles smaller than 200 mesh decreased from 70% to 40%, the combustion performance of the mixed coal powder decreased to varying degrees. This indicates that the coarser particle size led to a decrease in the combustion performance of the mixed coal powder. However, compared with the combustion performance of the mixed coal powder in the baseline period, even when the proportion of 200-mesh particles was reduced by 30%, the combustion performance of the mixed coal powder was still significantly better than that of the mixed coal powder in the baseline period.

[0052] Example 4

[0053] A baseline blend of coal with a bituminous coal ratio of 40% and 70% of the pulverized coal containing particles smaller than 200 mesh was selected. The combustion performance of the baseline blend of coal was tested using a WCT-2C differential thermal balance, specifically including the following steps:

[0054] The differential thermal experiment was conducted in an air atmosphere with a heating rate of 20℃ / min. The temperature was increased from 30℃ to 800℃ and held for 5 minutes before the experiment ended. The TG curve was plotted and analyzed using Origin software, and the obtained TG curve represents the combustion performance.

[0055] The combustion performance of blended coals with a bituminous coal ratio of 70% and particles smaller than 200 mesh comprising 60%, 50%, 40%, and 30% respectively was tested using the same method. The results are shown in [link to results]. Figure 4 , Figure 4 This is a comparison curve of the combustion performance of mixed coal provided in Example 4 of this application. Figure 4It can be seen that as the proportion of bituminous coal increased to 70% and the proportion of 200-mesh pulverized coal particles decreased from 70% to 40%, the combustion performance of the mixed pulverized coal remained at a relatively stable level. The increase in pulverized coal particle size did not have a significant impact on the combustion behavior of the mixed pulverized coal, indicating that appropriately increasing the particle size can still maintain good combustion performance of pulverized coal under high bituminous coal proportion conditions. Therefore, the smelting cost of blast furnaces can be reduced synergistically by adding a high proportion of bituminous coal and reducing the power consumption of pulverizing.

[0056] As can be seen from Examples 1-4, the existing production conditions in which the proportion of bituminous coal in the base period blended coal is 40% and the proportion of 200-mesh pulverized coal in the pulverized coal injection is 70% can be converted to a 70% bituminous coal proportion and a 40% proportion of 200-mesh pulverized coal particles for production. This will not affect production. The smelting cost of the blast furnace can be reduced by adding a high proportion of bituminous coal and reducing the power consumption of pulverizing.

[0057] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for detecting the reasonable particle size of mixed coal with different bituminous coal ratio, characterized in that, The method comprises the following steps: 1) obtaining differential thermal curves of a reference period mixed coal and a to-be-tested mixed coal by using a differential thermal balance, wherein the to-be-tested mixed coal has different proportions of bituminous coal and / or different particle size distributions from the reference period mixed coal; 2) comparing the differential thermal curves of the reference period mixed coal and the to-be-tested mixed coal to determine a reasonable particle size of the to-be-tested mixed coal.

2. The detection method according to claim 1, characterized in that, The differential thermal balance is a microcomputer differential thermal balance.

3. The detection method according to claim 2, characterized in that, The parameters of the differential thermal balance are as follows: air atmosphere, a temperature rising rate of 15-25 ℃ / min, a temperature rising temperature of 700-900 ℃, and a holding time of 3-8 min.

4. The detection method according to claim 3, characterized in that, The parameters of the differential thermal balance are as follows: air atmosphere, a temperature rising rate of 20 ℃ / min, a temperature rising temperature of 800 ℃, and a holding time of 5 min.

5. The method of claim 1, wherein, The proportion of bituminous coal in the reference period mixed coal is 40%.

6. The detection method according to claim 5, characterized in that, In the reference period mixed coal, the proportion of bituminous coal is 40%, and the proportion of coal particles with a size of less than 200 mesh is 70%.

7. The detection method according to claim 6, characterized in that, In the to-be-tested mixed coal, the proportion of bituminous coal is 40%, and the proportion of coal particles with a size of less than 200 mesh is 30-65%.

8. The detection method according to claim 7, characterized in that, In the to-be-tested mixed coal, the proportion of bituminous coal is 40%, and the proportion of coal particles with a size of less than 200 mesh is 30%, 40%, 50% or 60%.

9. The detection method of claim 6, wherein, In the to-be-tested mixed coal, the proportion of bituminous coal is 45-70%, and the proportion of coal particles with a size of less than 200 mesh is 30-65%.

10. The detection method according to claim 9, characterized in that, In the to-be-tested mixed coal, the proportion of bituminous coal is 50%, 60% or 70%, and the proportion of coal particles with a size of less than 200 mesh is 30%, 40%, 50% or 60%.

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