CN113185990B - Evaluation method of key indexes of coking coal - Google Patents

Abstract

The invention belongs to the technical field of metallurgical coking, and particularly relates to an evaluation method of key indexes of coking coal. And compared with coking process behaviors of different coking coals at different temperatures, the method has important reference value for the key performance evaluation of the coking coals, the reasonable blending in the coking coal blending, the influence difference on the coke quality and the like.

Description

An evaluation method for key indicators of coking coal

technical field

The invention belongs to the technical field of metallurgy and coking, and in particular relates to an evaluation method for key indicators of coking coal.

Background technique

Due to the differences in coal quality characteristics of different coal types or the same coal type, different coking states will appear at different temperatures during the coking process, and finally different coke quality will be shown. Studying the coking state of coking coal at different temperatures can not only evaluate the coal quality of coking coal and guide coal blending, but also help to start from the mechanism research, in-depth grasp of the characteristics of different coking coals, and make the guidance of coal blending and coking more scientific and reasonable. In addition, when obtaining coking products in the laboratory, it should be considered that during the retort heating of industrial coke ovens, gaseous products are continuously produced and flow through the coke layer, furnace wall or furnace roof with higher temperature. Therefore, during the research process, it should be Consider secondary pyrolysis of gaseous products.

At present, the coal quality evaluation of coking coal mostly starts from the existing coal quality indicators, including caking index, colloid layer index, reflectivity, fluidity, swelling degree, coke microstructure, etc. of coking coal. These indicators need to be based on the requirements of relevant standards , separate sample preparation, detection, and retrieval process are cumbersome, and the parameter indicators such as particle size and bulk density are quite different from the actual production control indicators, and corresponding adjustments cannot be made.

Patent document 1 "A method for measuring the coking rate of coking coal (CN201710418693.X)" Put the iron box containing the coking coal to be tested into the carbonization chamber of the production coke oven for dry distillation until the coke is mature, and calculate the coking rate of the coking coal; Patent Documents 2 and 3 "A device for measuring coking expansion pressure (CN201320815119.5)"; "A device for measuring coking coal expansion pressure (CN201320817001.6)" uses a piston structure and a pressure sensor to detect the expansion pressure in the coking process. "A coal quality assessment method for coking coal with a volatile content of 27-29%" "Classification of coking coal with a volatile content of 32-37% and coking coal blending method" using the average maximum reflectance of vitrinite, viscosity Coal quality assessment and classification are carried out with indicators such as knot index G value and volatile matter; "A detection method and device for pyrolysis-coking behavior of coal" detects indicators such as the maximum thickness of the colloidal layer and the maximum expansion pressure through equipment monitoring. The detection method disclosed in the above documents is different from the detection principle and method disclosed in the present invention, and the detection process can only measure one of the indicators.

The current laboratory coking method is mainly to obtain coke quality and chemical product yield under different coal blending conditions, and it is impossible to observe the coking state of coking coal at intermediate temperatures, and the use of coal samples ranges from several kilograms to several hundred kilograms, and the workload of coking operations Large, high energy consumption, serious environmental pollution; or the use of a small amount of coal samples, the test conditions and production are quite different.

Contents of the invention

The present invention aims to solve the problem that the coking state of coking coal at an intermediate temperature cannot be observed in the current trial laboratory coking method to obtain the coke quality and the yield of chemical products under different coal blending conditions, and the coal sample is used in a range of several kilograms to several hundred kg, large coking operation workload, high energy consumption, serious environmental pollution; or the use of a small amount of coal samples, large differences between test conditions and production, etc., the present invention can observe and detect the coking state of coking coal at different temperatures, the present invention The invention uses a small amount of coal to carry out tests, not only can study the coking state and gas composition at different temperatures, but also has guiding significance for studying the coking process behavior of coking coal and predicting the impact of coke production and quality. Comparing the coking process behavior of different coking coals at different temperatures also has important reference value for the key performance evaluation of coking coals, the reasonable allocation in coking coal blending, and the comparison of the impact of coking coal quality.

The technical solution of the present invention is: a method for evaluating key indicators of coking coal, specifically comprising the following steps:

(1) Prepare 60-200 g of coking coal with different proportions as the coal sample to be tested and the reference coal sample, the percentage of the coal sample with a particle size of > 5 mm in the coking coal to the total coal sample mass is ≤ 3%, and the reference coal sample Coal samples are commonly used coal samples with known coal quality parameters;

(2) Take two different coking coals of the same quality in step (1), measure the moisture content, and adjust the moisture content of the two coking coals to be consistent, and put them into two coal containers of the same size according to the same conditions. And tamping, vibrating and compacting the coking coal until the height of the coking coal after loading is the same to ensure that the bulk density of the test coal sample and the reference coal sample are the same. The coal charging container is a barrel with a circular cross section. Put the gas-permeable resistance layer of the same quality into the barrel-shaped heating furnace body on the upper surface of the coking coal in the coal charging container, and cover the coal charging container with a cover with a gas output pipe, and the coal charging container The space between the cover and the cover is sealed with high-temperature heat-resisting asbestos to prevent air leakage, so that the pressure of the two coking coals is the same during the process of thermal expansion and contraction, and the temperature of the resistance layer, coking coal and the heating furnace body is measured by a thermocouple, and the heating furnace is used to Coking different coking coals under the same conditions in step (1), including: making the temperature measured by thermocouples installed at the same position in different coking coals, resistance layers, and heating furnace bodies consistent at the same coking time; controlling the resistance layer The internal temperature distribution is within the actual measurement range of the furnace roof space temperature in the coke oven carbonization chamber;

Bulk density in the above steps = mass/volume of coal. The diameter of the coal charging container is fixed, and the bottom area is a fixed value. The bulk density can be adjusted by adjusting the coal loading height. When the coal is directly loaded into the coal charging container, the bulk density is basically low. The coal height will be reduced, and when the coal loading height is the same and the coal loading is the same, the bulk density will be the same.

(3) Coal quality evaluation: When the coking coal reaches the target temperature in the coal container, take out the coal container and cool it down to room temperature naturally; detect the relevant parameters of the coal samples to be tested and the coke blocks of the reference coal samples obtained after cooling, and compared to each other, including:

Expansion comparison, set the target temperature at 700°C~850°C, measure the height of the coke of the coal sample to be tested, when the difference between the height of the coke of the coal sample to be tested and the height of the coke of the reference coal sample is greater than the height of the reference coal 2% of the coke height of the sample, the expansibility: the coal sample to be tested > the reference coal sample; when the difference between the height of the coke block of the reference coal sample and the coke height of the coal sample to be tested is greater than the coke block of the reference coal sample When the height is 2%, expansion: the coal sample to be tested < the reference coal sample; when the difference between the coke height of the coal sample to be tested and the coke height of the reference coal sample does not exceed ±2 of the coke height of the reference coal sample %, expansion: the detected coal sample ≈ the reference coal sample, and the two have no significant difference in the production expansion adjustment.

Coking coal exhibits different expansibility during the coking process. Although the coal sample shrinks in the later stage of coking, at the height of the coal sample, due to the limitation of no external pressure, the coking shrinkage is difficult to reach the initial coal loading height or lower, that is, after coking. Therefore, the expansion of coking coal can be reflected by the change of coke block height. However, in order to reduce the negative impact of shrinkage on expansion, the temperature should be controlled as low as possible, but the smooth removal of coke blocks should be ensured. Therefore, the expansion measurement temperature is controlled at 700°C~850°C.

Shrinkage ratio comparison, set the target temperature to 750°C~1000°C, directly compare the diameter of the coke block of the coal sample to be tested and the coke block of the reference coal sample, and obtain the shrinkage rate: when the diameter of the coke block of the coal sample to be tested is larger than the reference coal sample When the coke block diameter of the coal sample to be tested is more than 0.01cm, the shrinkage rate: the coal sample to be tested > the reference coal sample; when the coke block diameter of the coal sample to be tested is less than the coke block diameter of the reference coal sample by more than 0.01cm, the shrinkage rate: the coal sample to be tested <Baseline coal sample; when the difference between the coke diameter of the coal sample to be tested and the coke piece diameter of the reference coal sample is within ±0.01cm, the shrinkage rate: the coal sample to be tested ≈ the reference coal sample, adjust the shrinkage of the coal sample No significant difference was affected.

Although the shrinkage temperature of different coking coals is different, it is mainly used to guide the coke pushing in the coke oven. Since the coke pushing in the coke oven is after the coke cake is 950°C, as long as each coke block reaches the shrinkage temperature, the change is small. At the same time, the operation Convenient, the shrinkage research temperature is controlled at 750°C~1000°C.

The measurement of the diameter of the focal block is accurate to the second decimal place, and the unit is cm.

Cohesiveness: set the target temperature to 750°C~1000°C, when the coke generated by the coal sample to be tested is heavier than the coke generated by the reference coal sample by 1g or more, the cohesiveness: the coal sample to be tested > the reference coal sample; when When the weight of the coke generated by the coal sample to be tested is more than 1g lighter than that of the reference coal sample, the cohesiveness: the coal sample to be tested < the reference coal sample; When the difference in the weight of the coke slag is within the range of ±1g, the cohesiveness: the coal sample to be tested ≈ the reference coal sample.

Since the cohesiveness is reflected in the coking of coking coal to form coke, the coking coal can be formed into coke, and the temperature is controlled at 750°C~1000°C.

Coking rate: set the target temperature at 750°C~1000°C, when the difference between the coke weight of the coal sample to be tested (that is, the total weight of coke block + coke slag) and the coke weight of the reference coal sample exceeds 1% of the coke weight of the reference coal sample %, the coking rate: the coal sample to be tested > the reference coal sample; when the difference between the coke weight of the reference coal sample and the coke weight of the coal sample to be tested exceeds 1% of the coke weight of the reference coal sample, the coking rate: to be The measured coal sample < the benchmark coal sample, when the difference between the coke weight of the coal sample to be tested and the coke weight of the benchmark coal sample does not exceed ±2% of the coke weight of the benchmark coal sample, the coke formation rate of the two is close, which is beneficial to the increase of coke production No noticeable effect.

This indicator is the weight percentage of the coke block left after the volatile products have been produced. The volatile products are mainly produced in the middle stage of coking, and relatively few in the later stage. In order to detect synchronously with other indicators, the temperature is controlled at 750°C~1000°C.

Therefore, in addition to the specific temperature range for expansion index detection and research, other tests can be carried out simultaneously, and the control temperature can also be determined according to the key points of index detection.

Further, the evaluation method further includes the step: (4) When the gas needs to be sampled and tested, connect the gas bag to collect the gas.

Further, a resistance heating wire is provided on the side of the resistance layer facing the cover.

Further, the diameter of the resistance layer is the same as the inner diameter of the coal charging container, and the resistance layer makes the gas pressure generated by the carbonization of coking coal in the coal charging container before passing through the resistance layer as the target pressure, and the target pressure is 80-120 Pa, The weight of the resistance layer is adjusted in the following manner: by inserting one end of the gas guide tube under the resistance layer, the other end of the gas guide tube is connected to a micromanometer, and at the same time, the coking coal is pre-heated under the same heating conditions using the heating furnace body and the pressure in the tube is measured. Gas pressure, according to the difference between the target pressure and the gas pressure, increase or decrease the weight of the resistance layer until the gas pressure is within the target pressure range.

Further, the method to make the temperature measured by thermocouples installed in the same position in different coking coals, resistance layers, and heating furnace bodies consistent at the same coking time is to heat the furnace body through silicon carbide rods and adjust the heating of silicon carbide rods. Power, so that the coking coals in different coal charging containers are heated at the same heating rate.

Coal quality evaluation in the step (3): When the coking coal reaches the target temperature in the coal charging container, take out the coal charging container from the heating furnace body, and cool it to room temperature naturally; detect the cooled coal sample and reference coal The expansion, shrinkage, coking rate and cohesiveness of the sample coke block:

Expansion = (coke block height - coal loading height) / coal loading height * 100

Shrinkage rate = (coal diameter - coke block diameter) / coal diameter * 100

Coking rate=coke weight/coal weight*100

Cohesiveness = coke weight / coal weight * 100

Among them, the coal diameter is the diameter of the coal loading container, the coal loading height is the coal loading height when the coal sample to be tested and the reference coal sample are put into the coal loading container after being tamped and vibrated and compacted to reach the bulk density, and the coal weight is the loading height. The quality of the coal put into the coal container, the coke block height is the height of the coking coal in the coal container after carbonization, the coke block diameter is the diameter of the coking coal in the coal container after carbonization, and the coke block weight is the coking coal carbonization in the coal container The final weight minus the quality of coke residue.

Compared with the prior art, the present application has the following advantages and beneficial effects:

The present invention starts from the mechanism research of coking process, puts a small amount of coal sample into a unique coal charging container, and then puts it into a heating furnace, and studies the coking state and chemical products of coking coal at different temperatures through temperature adjustment and control. Coking coal coking mechanism research, coal quality evaluation, coal blending guidance, etc. have important guiding significance. Moreover, the invented method uses less coal samples, the simulation process is close to the production, produces less toxic and harmful products, eases the difficulty of treatment, improves the operating environment, and reduces pollution. When the gas is not monitored, the coal charging container can be put into any heating furnace, as long as the heating furnace can measure the coal center temperature, it has strong adaptability. A variety of coking coal key indicators can be measured through one coking experiment.

Description of drawings

Fig. 1 is the structural representation of combined heating furnace used in the embodiment;

1-furnace body, 11-lower furnace body, 13-wall body, 131-through hole, 2-silicon carbide rod, 21-heating hole, 4-coal charging container, 41-barrel body, 42-box body, 5- Drag handle, 6-resistance layer, 61-annular enclosure, 7, electric heating cover, 8-first thermocouple, 9-second thermocouple, 10-catheter, 14-third thermocouple.

Detailed ways

The combined heating furnace used in the following examples is shown in Figure 1. The combined heating furnace includes a furnace body 1, an electric heating cover 7, and a coal charging container 4. The furnace body 1 is assembled from refractory bricks, including a lower furnace body 11 and a surrounding wall. body 13, the surrounding wall body 13 surrounds the cavity for accommodating the coal charging container 4 above the lower furnace body 11, and the lower furnace body 11 is provided with heating holes 21 that go deep into the lower furnace body 11 from the side, and all the heating holes 21 are arranged close to the lower furnace body. At the upper end surface of the furnace body 11, silicon carbide rods 2 are embedded in the heating holes 21, and the coal charging container 4 is made of high temperature resistant materials, and is divided into an upper barrel body 41 and a box body 42 located at the lower part of the barrel body 41, the box body 42 and the surrounding wall One end of the body 13 close to the lower furnace body 11 is provided with through holes 131 corresponding to each other for inserting the third thermocouple 14. The upper part of the outer circumference of the barrel body 41 is provided with a drag handle 5, and the drag handle 5 reaches the bottom end of the coal charging container 4. The height is not lower than the depth of the cavity, the drag handle 5 is spaced apart from the upper edge of the barrel body 41, the electric heating cover 7 is buckled upside down on the upper end of the barrel body 41, and the lower edge of the electric heating cover 7 is against the drag of the barrel body 41. The handle 5 and the electric heating cover 7 are provided with a conduit 10 connected to the gas treatment system and a heating resistance wire. The first thermocouple 8 and the second thermocouple 9 respectively pass through the electric heating cover 7 to measure the upper space of the electric heating cover 7 and the barrel body 41 The temperature of the inner coal seam, the inner circumference of the electric heating cover 7 and the outer circumference of the staving 41 match each other, so that the electric heating cover 7 and the staving 41 are hermetically connected.

As a preferred technical solution, the electric heating cover 7 is provided with a resistance layer 6, the resistance layer 6 is a mesh cage woven from a high-temperature resistant wire mesh, and the mesh cage is filled with a block-shaped high-temperature-resistant and stable material, which does not exceed the required temperature. Changes in physical and chemical properties occur, the shape is not limited, the size of a single block is 10~12mm, the outline of the mesh cage coincides with the inner circumference of the electric heating cover 7, and the first thermocouple 8 penetrates into the resistance layer 6 after passing through the electric heating cover 7 .

As a preferred solution, the end face of the resistance layer 6 facing away from the electric heating cover 7 is also connected to the annular surrounding sheet 61, and the inner circumference and outer circumference of the annular surrounding sheet 61 coincide with the outer circumference of the barrel body 41 and the inner circumference of the electric heating cover 7 respectively, The hat-shaped structure formed by the annular surrounding piece 61 and the resistance layer 6 is buckled upside down on the upper end of the barrel body 41 .

As a preferred solution, a drag handle 5 is also provided on the lower part of the outer circumference of the annular surrounding sheet 61 to facilitate the taking and placing of the resistance layer 6 .

During use, put coal sample in barrel body 41, heat lower furnace body 11 by silicon carbide rod 2, transfer heat to barrel body 41 by box body 42 again, the temperature in the third thermocouple 14 measures box body 42, is equivalent to Measure the temperature of the combustion chamber, and the second thermocouple 9 measures the temperature of the coal sample, which is equivalent to measuring the final coking temperature of the coke cake center, so the heating can be stopped at different temperatures (that is, the coal charging container is taken out of the furnace body), and obtained For the coke block at the corresponding temperature, the temperature field inside the electric heating cover 7 is uniform, and the first thermocouple 8 is inserted into the resistance layer 6 to measure the temperature, so that the temperature of the electric heating cover 7 can be adjusted within the range of 500~1000°C, simulating a coke oven The temperature of the top space is different, and the generated gas is cracked by secondary heating, which is close to the actual production, so the heating can be stopped at different temperatures, and by-products at corresponding temperatures can be obtained.

The combination of the above devices can be added or subtracted according to the needs of the test and research. If the research product is not needed, the electric heating cover 7 and the resistance layer 6 can be removed, and the generated gas is directly discharged or treated after airtight suction.

In the following examples, the reference coal sample used is coking coal, and both the reference coal sample and the new coal sample are put into a coal charging container during the experiment and compacted into a circular cake shape.

Example 1: Analysis of CH ₄ and H ₂ in gas produced by blending coal at 550°C and 620°C

1) Weigh 60g of the mixed coal sample, prepare the sample, and control the quality of the diameter > 5mm to account for 2% of the total coal sample mass;

2) Adjust the coal moisture into the furnace to the target moisture content of 6% and bulk density of 0.78g/cm ³ on a dry basis;

3) Put the coal charging container 4 in the furnace body 1, put the coal sample in the barrel body 41, and add coal charging briquettes with holes on the coal sample;

4) Add a resistance layer 6 on the coal charging container 4, and inside the resistance layer 6 are high-temperature-resistant high-alumina balls;

5) Put a heating mantle 7 on the resistance layer 6, and close the open end of the coal charging container, and control the temperature at 700°C;

6) The rooms between different devices (between the coal charging container 4 and the heating mantle 7) are sealed with high-temperature heat-resistant asbestos to ensure no air leakage;

7) Insert the temperature control thermocouple (the third thermocouple 14) between the furnace body 1 and the coal charging container 4, insert the second thermocouple 9 into the center of the coal seam, and insert the first thermocouple 8 into the heating mantle 7, the thermoelectric The diameter of the pair is 5mm;

Connect the gas cooling device, collect the gas at the gas outlet at 550°C and 620°C, and test the composition.

Table 1 H ₂ and CH ₄ contents in coal gas at 550°C and 620°C

Embodiment 2 Comparing the expansibility of coal sample 1# and reference coal sample

(The benchmark coal sample is Henan coking coal, and coal sample 1# is Shandong fat coal)

Take the temperature measurement point within the expansion measurement temperature: 850°C is the target temperature, the following methods are used for both the benchmark coal sample and the coal sample to be tested. When the benchmark coal sample data is known, no further measurement is required. In this embodiment, the known benchmark coal The mass of the sample is 100g, the water content is 11%, and the bulk density on a dry basis is 0.76g/cm ³ . cm.

1) Weigh coking coal sample 1# 100g, prepare samples, and control the quality of coal samples with a diameter > 5mm to account for 2% of the total coal sample mass;

2) Adjust the control index of coal sample 1# to be the same as that of the reference coal sample, that is, the water content is 11%, and then put coal sample 1# into the cylinder 41 of the coal charging container 4 of the above-mentioned combined heating furnace, and vibrate the coal charging container 4 to ensure The height of the coal sample after entering the coal charging container 4 is the same as the benchmark coal sample, which is 3.6cm, and its dry basis bulk density is calculated to be consistent with the benchmark coal sample, which is 0.76g/cm ³ ;

3) There is no coal charging briquette with holes on the coal sample, no resistance layer and electric heating cover, only the cover is covered; 4) Insert the temperature control thermocouple (the third thermocouple 14) into the furnace body 1 and the coal charging container 4, insert the second thermocouple 9 to the center of the coal seam, and insert the first thermocouple 8 into the cover body, and the diameter of the thermocouple is 5mm;

5) When coal sample 1# is heated to 850°C, stop heating, take out the coal container immediately, and let it cool to room temperature.

6) Measure the height of the coke block obtained from coal sample 1# to be 6.9cm.

7) Judgment of expansibility: Compared with the reference coal sample, the coke block height of coal sample 1# is 64.3% higher than its coke block height, (6.9-4.2)/4.2=64.3%, far greater than 2%, indicating that the coal sample The expansibility of 1# is much better than that of the reference coal sample.

8) According to the national standard, the Aurya expansion b values of coal sample 1# and reference coal sample were detected by the Aurora dilatation tester, which were 160% and 15% respectively. It can be seen that the expansion of coal sample 1# is much better than that of the reference coal sample , which is the same as the result of this experiment.

Example 3 Comparing the shrinkage rate, coking rate and cohesiveness of coal sample 2# and reference coal sample

(The benchmark coal sample is Henan coking coal, and coal sample 2# is Shandong 1/3 coking coal)

Take shrinkage rate, coking rate, temperature measurement point in the cohesiveness measurement temperature: 870 ℃, benchmark and to-be-tested coal sample all adopt the following method, in the present embodiment, benchmark coal sample quality is 100g, moisture content is 11%, dry The base bulk density is 0.76g/cm ³ , the radius after being loaded into the coal charging container 4 is 3.2cm, the diameter of the obtained coke block is 5.51cm, the total weight of coke block + coke slag is 69.2g, and the weight of coke slag is 10.7g:

1) Weigh coking coal sample 2# 100g, prepare samples, and control the quality of coal samples with a diameter > 5mm to account for 3% of the total coal sample mass;

2) Adjust the control index of coal sample 2# to be the same as that of the reference coal sample, that is, the water content is 11%, and the oscillating coal charging container 4 ensures that the radius and coal loading height of the coal sample after being loaded into the coal charging container 4 are the same as the reference coal sample, which is 3.2 cm and 3.6cm, the calculated bulk density on a dry basis is consistent with the bulk density of the reference coal sample, which is 0.76g/cm ³ ;

3) There is no coal charging briquette with holes on the coal sample, no resistance layer and electric heating cover, only the cover is covered; 4) Insert the temperature control thermocouple (the third thermocouple 14) into the furnace body 1 and the coal charging container 4, insert the second thermocouple 9 to the center of the coal seam, and insert the first thermocouple 8 into the cover body, and the diameter of the thermocouple is 5mm;

5) When coal sample 2# is heated to 870°C, stop heating, immediately take out the coal container, and let it cool to room temperature.

6) The diameter of the coke block obtained by measuring coal sample 2# is 5.48cm, the total weight of coke block + coke slag is 61.2g, and the weight of coke slag is 3.9g.

Judging the shrinkage rate: 5.48cm<5.51±0.01cm, the coke block diameter of coal sample 2#<the reference coal sample diameter+0.01cm, indicating that the shrinkage rate of coal sample 2# is greater than that of the reference coal sample;

Judging the coking rate: (61.2-69.2)/69.2=-11.6%, under the same coal sample quality, the coke weight (coke block + coke residue) of coal sample 2# is 11.6% lighter than the coke weight of the reference coal sample, The difference is much greater than 1%, indicating that the coking rate of coal sample 2# is lower than that of the reference coal sample;

Judgment of cohesiveness: the difference between the coke weight of coal sample 2# and the reference coal sample is 6.8g, far greater than 1g, indicating that the cohesiveness of coal sample 2# is better than that of the reference coal sample.

(8) Refer to the corresponding national standards (the detection method of the coking rate, refer to its definition - refers to the percentage of washed coal converted into coke in the coking process, and the calculation method is obtained by dry distillation of coking coal at high temperature (above 950°C) The percentage of coke mass in the furnace coal mass, the detection of caking index is carried out in accordance with GB/T5447-1997 "Measurement method of caking index of bituminous coal", and the detection of final shrinkage is in accordance with GB/T 479-2016 "Determination of colloidal layer index of bituminous coal method), the final shrinkage indicators of the tested coal sample and the reference coal sample were 23mm and 45mm respectively; the coking rates were 72% and 58% respectively, and the cohesive index was 83 and 88 respectively. It can be seen that the shrinkage of coal sample 2# It is higher than the benchmark coal sample, the coking rate is lower than the benchmark coal sample, and the caking index is better than the benchmark coal sample, all of which are the same as the test results.

Quantitatively express the expansion, shrinkage, coking rate and cohesiveness of different coal samples

Take the detection results of each coking coal (coal sample 3#, coal sample 4#, coal sample 3# is 1/3 coking coal 2#, coal sample 4# is coking coal 2#, 2# indicates another origin) as the output value, The expansibility, shrinkage rate, coking rate and caking property of different coal samples (coal sample 3#, coal sample 4#) are obtained.

Expansion = (coke block height - coal loading height) / coal loading height * 100

Shrinkage rate = (coal diameter - coke block diameter) / coal diameter * 100

Coking rate=coke weight/coal weight*100

Cohesiveness = coke weight / coal weight * 100

Claims (6)

1. A method for evaluating key indexes of coking coal specifically comprises the following steps:

(1) Preparing 60 to 200g coking coals with different proportions as a coal sample to be measured and a reference coal sample respectively, wherein the mass of the coal sample with the granularity of 5mm in the coking coal accounts for less than or equal to 3 percent of the mass of the total coal sample, and the reference coal sample is a coal sample with commonly used known coal quality parameters;

(2) Taking two different coking coals with the same mass in the step (1), measuring the water content, adjusting the water content of the two coking coals to be consistent, respectively filling the two coking coals into two coal charging containers with the same size according to the same condition, tamping, vibrating and compacting the coking coals until the heights of the coking coals after filling are the same, ensuring that the bulk densities of a coal sample to be measured and a reference coal sample are the same, wherein the coal charging container is a barrel with a circular cross section, putting the coal charging container into a barrel-shaped heating furnace body, arranging a permeable gas resistance layer with the same mass on the upper surface of the coking coals in the coal charging container, covering a cover with a gas output pipeline on the coal charging container, sealing the coal charging container and the cover by using high-temperature resistant heat-insulation asbestos to prevent air leakage, ensuring that the pressure of the two coking coals is the same in the heating expansion and shrinkage processes, measuring the temperature of the resistance layer, the coking coals and the heating furnace body by using a thermocouple, and utilizing the heating furnace to ensure that the different coking coals in the step (1) are coked according to the same condition, and comprises the following steps: the temperature measured by thermocouples arranged at the same position in different coking coals, resistance layers and heating furnace bodies is consistent when the coking time is the same; controlling the temperature in the resistance layer to be distributed in the actual measurement range of the temperature of the furnace top space in the coke oven carbonization chamber;

(3) And (3) evaluating the coal quality: when the coking coal reaches the target temperature in the coal charging container, taking out the coal charging container from the heating furnace body, and naturally cooling to room temperature; detecting and comparing the relevant parameters of the cooled coking blocks of the coal sample to be detected and the reference coal sample, comprising the following steps:

(a) Comparison of the expansibility: setting a target temperature to be 700-850 ℃, measuring the height of the coke block of the coal sample to be measured, and when the difference between the height of the coke block of the coal sample to be measured and the height of the coke block of the reference coal sample is more than 2% of the height of the coke block of the reference coal sample, performing expansibility: the coal sample to be measured is larger than the reference coal sample; when the difference between the height of the coke block of the reference coal sample and the height of the coke block of the coal sample to be detected is greater than 2% of the height of the coke block of the reference coal sample, the expansibility: the coal sample to be measured < the reference coal sample; and when the difference between the height of the coke block of the coal sample to be detected and the height of the coke block of the reference coal sample does not exceed +/-2% of the height of the coke block of the reference coal sample, the expansibility: the detection coal sample is approximately equal to the reference coal sample, and the detection coal sample and the reference coal sample have no obvious difference influence on production expansion adjustment;

(b) Shrinkage comparison: setting the target temperature to be 750-1000 ℃, directly comparing the diameters of the coke blocks of the coal sample to be detected and the reference coal sample to obtain the shrinkage rate: when the diameter of the coke block of the coal sample to be measured is more than 0.01cm larger than that of the coke block of the reference coal sample, the shrinkage rate is as follows: the coal sample to be measured is larger than the reference coal sample; when the diameter of the coke block of the coal sample to be measured is smaller than that of the coke block of the reference coal sample by more than 0.01cm, the shrinkage rate is as follows: the coal sample to be measured < the reference coal sample; when the difference value between the diameter of the coke block of the coal sample to be measured and the diameter of the coke block of the reference coal sample is within the range of +/-0.01 cm, the shrinkage rate is as follows: the coal sample to be measured is approximately equal to the reference coal sample, and no obvious difference influence is caused on the shrinkage adjustment of the coal sample;

(c) Adhesion: setting the target temperature to be 750-1000 ℃, and when the weight of the coke residue generated by the coal sample to be detected is more than 1g than that of the coke residue generated by the standard coal sample, the cohesiveness: the coal sample to be measured is larger than the reference coal sample; when the weight of the coke residue generated by the coal sample to be detected is more than 1g lighter than that of the coke residue generated by the standard coal sample, the caking property is as follows: the coal sample to be measured < the reference coal sample; when the difference between the weight of the coke residue generated by the coal sample to be detected and the weight of the coke residue generated by the standard coal sample is within the range of +/-1 g, the cohesiveness: the coal sample to be measured is approximately equal to the reference coal sample.

2. The evaluation method according to claim 1, characterized in that the evaluation method further comprises the steps of: (4) When the gas needs to be sampled and tested, the gas bag is connected to collect the gas.

3. The method of claim 1, wherein the cover is provided with a heating resistance wire on the side of the resistance layer facing the cover.

4. The evaluation method according to any one of claims 1 and 3, wherein the diameter of the resistance layer is the same as the inner diameter of the coal charging container, the resistance layer enables the gas pressure of the gas generated by carbonization of the coking coal in the coal charging container to be a target pressure before the gas passes through the resistance layer, the target pressure is 80-120pa, and the weight of the resistance layer is adjusted according to the following modes: one end of the gas guide pipe is inserted below the resistance layer, the other end of the gas guide pipe is connected with the micro-pressure meter, the coking coal is heated in advance under the same heating condition by using the heating furnace body, the gas pressure in the guide pipe is measured, and the weight of the resistance layer is increased according to the difference value of the target pressure and the gas pressure until the gas pressure is within the target pressure range.

5. The evaluation method according to claim 1, wherein the method for making the temperatures of the coking coals, the resistance layer and the thermocouples installed at the same position in the heating furnace body consistent at the same coking time comprises the following steps: the heating power of the silicon carbide rods is adjusted through the silicon carbide rod heating furnace body, so that the coking coals in different coal charging containers are heated up at the same heating rate.

6. The evaluation method according to claim 1, wherein the coal quality evaluation in the step (3): when the coking coal reaches the target temperature in the coal charging container, taking out the coal charging container from the heating furnace body, and naturally cooling to room temperature; and (3) detecting the expansibility, the shrinkage and the cohesiveness of the cooled coke blocks of the coal sample to be detected and the reference coal sample:

expansibility = (coke block height-coal charge height)/coal charge height 100

Shrinkage = (coal diameter-coke briquette diameter)/coal diameter 100

Cohesiveness = coke mass weight/coal weight 100

The coal diameter is the diameter of the coal charging container, the coal charging height is the coal charging height when the coal sample to be measured and the reference coal sample reach the bulk density after being charged into the coal charging container and then being tamped and vibrated and compacted, the coal weight is the mass of the coal charged into the coal charging container, the coke briquette height is the height of the carbonized coking coal in the coal charging container, the coke briquette diameter is the diameter of the carbonized coking coal in the coal charging container, and the coke briquette weight is the weight of the carbonized coking coal in the coal charging container minus the mass of the coke slag.

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