Method for reducing coke burning loss of horizontal heat recovery coke oven

Abstract

The invention relates to a method for reducing coke burning loss of a horizontal heat recovery coke oven. The method comprises the following steps: 1) carrying out primary coal distribution and tamping and secondary coal distribution and tamping on mixed coal in a coal tower tamping station; 2) after the third layer of coal is distributed, laying a coal seam from the machine side to the coke side on the surface of the coal cake after the third layer of coal is distributed; the thickness of the laid coal seam is 20-30 mm, and the weight is 1-1.5 tons; (3) third-layer tamping is executed, the height of the whole coal cake is controlled to be 1150-1160 mm, and the total weight is 67-75 tons; and 4) feeding the mashed coal cake into a carbonization chamber, and ending coking after coking time of 65-80 hours. In the process of tamping mixed coal into coal cakes, a coal layer is laid on the upper layer of the coal cakes, and the coal layer is compacted through a tamping machine after laying is completed; in the early and middle stages of coking, a coal seam and introduced air are combusted, combustion of mixed coal is avoided, and protection is formed; the coking rate is improved, the coal consumption is reduced, and the ash content and the strength index of the coke are stabilized.

Description

Technical Field

[0001] The invention relates to the technical field of heat recovery coke ovens in the coking industry, and in particular to a method for reducing coke burning loss in a horizontal heat recovery coke oven. Background Art

[0002] The heat recovery coke oven uses ramming coal charging and long turnover time for coking, so the quality of coke is improved or weakly caking coal is used to produce high-quality coke. At present, most heat recovery coke ovens can be equipped with 20-30% lean coal and anthracite for coking, saving a large amount of high-quality coking coal resources; the heat recovery coke oven coking production process is operated under negative pressure, and no pollutants escape; coal gas and chemical products are all burned in the furnace, and the high-temperature exhaust gas generated is recovered through waste heat to produce steam (for power generation or external steam supply); the exhaust gas is desulfurized and denitrified before it is discharged in compliance with the emission standards, and no phenol-cyanide wastewater is generated in the whole process. It is an environmentally friendly coking process throughout the production process.

[0003] The production process of heat recovery coke oven is roughly as follows: the mixed coal is sent into the coke oven coal tower through a belt conveyor, and a tamping station is set up under the coal tower to tamp the coal into briquettes and send them to the carbonization chamber for coking. Since the carbonization chamber furnace top, side walls and furnace bottom flame channel have a certain amount of heat, part of the coking coal is then heated to precipitate raw coal gas. An adjustable air intake valve is set on the furnace top to introduce primary air. The air and raw coal gas combustion generates heat to heat the furnace top space, and heat the briquettes through heat conduction and heat radiation. Since the air intake valve introduces insufficient air, the furnace top space is a reducing atmosphere, and the incompletely burned gas enters the machine side and coke side descending flame channels from the descending flame channel ports on the furnace walls on both sides of the carbonization chamber, and then enters the furnace bottom flame channel. The furnace bottom arch flame channel is divided into the machine side flame channel and the coke side flame channel, which are separately adjusted to achieve the purpose of uniform heating. Each furnace bottom flame channel has four sections of channels. Air is added in the channel to make the incompletely burned gas secondary combustion, generate heat to heat the furnace bottom bricks, and heat the bottom of the briquettes through heat conduction.

[0004] As the air introduced into the top of the carbonization chamber and the precipitated raw coal gas are burned, it is inevitable that the surface of the coal cake and coke cake will also be burned, which makes the coal consumption per ton of coke higher than that of ordinary coke ovens, the coke yield lower than that of ordinary coke ovens, the ash content of coke increases, and the overall strength decreases. Therefore, it is very important to control the amount of burnt loss on the surface of the coal cake and coke cake in the carbonization chamber, but there is no relevant report in the industry yet. Summary of the invention

[0005] The present invention provides a method for reducing the coke burning loss in a horizontal heat recovery coke oven. In the process of tamping the blended coal into coal cakes, a coal layer is spread on the coal cakes and then compacted by a tamping machine. In the early and middle stages of coking, the coal layer is burned with the introduced air, which prevents the blended coal from burning and forms a protection. The coking rate is improved, the coal consumption is reduced, and the ash content and strength index of the coke are stabilized.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for reducing coke burning loss in a horizontal heat recovery coke oven, the method comprising: during the process of tamping the blended coal into briquettes, laying a layer of coal on the briquettes, and then compacting with a tamping machine; the method specifically comprises the following steps:

[0008] 1) Low-grade coal is fed into the small coal bunker of the coke oven coal tower by belt conveyor in advance;

[0009] 2) The combined coal is placed and tamped for the first time and for the second time at the coal tower tamping station;

[0010] 3) After the third layer of coal is laid, the low-metamorphic coal is passed through the laying device, and the coal seam is laid on the surface of the coal cake after the third layer of coal is laid from the machine side to the coke side; the thickness of the laid coal seam of the low-metamorphic coal is 20-30 mm, and the weight is 1-1.5 tons;

[0011] 4) Then perform the third layer of tamping to tamp and level the coal cakes, and control the overall coal cake height to 1150-1160mm, with a total weight of 67-75 tons;

[0012] 5) The tamped coal cakes together with the coal supporting plate are sent to the coal loading car and transported to the carbonization chamber to be discharged from the furnace; after the coke pusher pushes out the mature coke in the carbonization chamber, the coke side furnace door is quickly closed, and the coal cakes together with the coal supporting plate are pushed into the carbonization chamber, and then the tail baffle of the coal cake is locked at the furnace mouth, the coal loading car pulls out the coal supporting plate, and the machine side furnace door is quickly closed to start coking;

[0013] 6) Send it to the carbonization chamber, and after 65 to 80 hours of coking time, the coking is completed.

[0014] The low metamorphic coal, such as lignite, long flame coal, etc.; its volatile matter V daf >33%, ash content A d ≤Combined coal ash content, sulfur content St<2%.

[0015] The low metamorphic coal needs to be crushed, and the proportion of particles with a size less than 3 mm after crushing accounts for more than 90wt%.

[0016] The coke yield of the obtained coke is over 74%; the coke is well matured and the coke volatile matter V daf Between 1.0% and 1.3%.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] Due to the low metamorphic coal volatile matter V dafIt is relatively high, and can produce a large amount of raw coal gas, which burns well with the introduced air, generates heat to heat the furnace top space, and heats the coal cakes through heat conduction and heat radiation, which can ensure that the coke is well matured and the strength of the whole furnace coke is ensured. In addition, the coal seam ash index is lower than the mixed coal ash content, and the coke ash content will not increase after the coal seam is burned out.

[0019] The details are as follows:

[0020] 1) The price of low-metamorphic coal is much lower than that of blended coal, which reduces the burning loss of normal coal and coke, and reduces the burning loss of high-quality blended coal by about 1.0% to 1.5%. Calculated based on the price difference of 700 yuan / ton between low-priced coal and blended coal, the cost per ton of coal is reduced by about 7 to 10 yuan, which has obvious economic benefits and plays an important role in reducing the cost per ton of coke.

[0021] 2) The coking rate using the method of the present invention reaches more than 74%.

[0022] 3) The coke produced by the method of the present invention is well matured, and the volatile matter V daf Between 1.0% and 1.3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0024] The specific implementation modes of the present invention are further described below in conjunction with examples. The following examples are used to specifically illustrate the contents of the present invention. These examples are only general descriptions of the contents of the present invention and do not limit the contents of the present invention.

[0025] Embodiment 1:

[0026] The low metamorphic coal selected is Shaanxi Yulin long flame coal. Its specific indicators and prices with blended coal are shown in Table 1.

[0027] Table 1 Indexes and prices of low metamorphic coal and blended coal

[0028]

[0029] First, the Shaanxi Yulin long flame coal is crushed, and the proportion of particles less than 3mm after crushing accounts for 90wt%. The crushed Shaanxi Yulin long flame coal is first sent to the small coal bunker of the coke oven coal tower through a belt; the matching coal is placed and tamped once and twice at the coal tower tamping station; after the third layer of coal laying, the low metamorphic coal passes through the distribution device and lays the coal layer on the surface of the coal cake from the machine side to the coke side, with a height of 20mm; then the third layer of tamping is performed to tamp the coal cake flat, and the overall coal cake height is controlled at 1150mm, with a total weight of about 69.5t (wet basis). The tamped coal cakes are sent to the coal loading car together with the coal supporting plate and transported to the carbonization chamber to be taken out of the furnace; after the coke pusher pushes out the mature coke in the carbonization chamber, the coke side furnace door is quickly closed, and the coal cakes are pushed into the carbonization chamber together with the coal supporting plate, and then the tail baffle of the coal cake is locked at the furnace mouth, the coal loading car pulls out the coal supporting plate, and the machine side furnace door is quickly closed to start coking. After 70 hours of coking time, coking is completed. Through observation, there is no burn damage on the surface of the coke cake. After the coke is mature, it is pushed out of the carbonization chamber and connected to the coke receiving car, and then sent to the dry quenching coke tank car for weighing. The total weight is about 45.9t (dry basis), the coking rate is 45.9t / (69.5t*11%)=74.2%, and the coke volatile matter V daf At 1.1%, the requirement is met.

[0030] Embodiment 2:

[0031] The low metamorphic coal selected is Shaanxi Yulin long flame coal. Its specific indicators and prices with blended coal are shown in Table 1.

[0032] First, the Shaanxi Yulin long flame coal is crushed, and the proportion of particles less than 3mm after crushing accounts for 95wt%. The crushed Shaanxi Yulin long flame coal is first sent to the small coal bunker of the coke oven coal tower through a belt; the matching coal is placed and tamped once and twice at the coal tower tamping station; after the third layer of coal laying, the low metamorphic coal passes through the distribution device and lays the coal layer on the surface of the coal cake from the machine side to the coke side, with a height of 30mm; then the third layer of tamping is performed to tamp the coal cake flat, and the overall coal cake height is controlled at 1160mm, with a total weight of about 70.2t (wet basis). The tamped coal cakes are sent to the coal loading car together with the coal supporting plate and transported to the carbonization chamber to be taken out of the furnace; after the coke pusher pushes out the mature coke in the carbonization chamber, the coke side furnace door is quickly closed, and the coal cakes are pushed into the carbonization chamber together with the coal supporting plate, and then the tail baffle of the coal cake is locked at the furnace mouth, the coal loading car pulls out the coal supporting plate, and the machine side furnace door is quickly closed to start coking. After 70 hours of coking time, coking is completed. Through observation, there is no burn damage on the surface of the coke cake. After the coke is mature, it is pushed out of the carbonization chamber and connected to the coke receiving car, and then sent to the CDQ coke tank car for weighing. The total weight is about 46.6t (dry basis), the coking rate is 46.6t / (70.2t*11%)=74.6%, and the coke volatile matter V daf At 1.15%, the requirement is met.

[0033] Comparative Example 1:

[0034] Unlike Example 1, a high-metamorphic coal layer is not laid on the coal cake, and the normal process flow is followed, namely: the mixed coal is laid and tamped once and twice at the coal tower tamping station; after the third layer of coal is laid, the third layer of tamping is then performed to tamp and level the coal cake, and the overall coal cake height is controlled at 1150mm, with a total weight of about 69.5t (wet basis). The tamped coal cake is sent to the coal loading car together with the coal supporting plate and transported to the carbonization chamber to be discharged from the furnace; after the coke pusher pushes out the mature coke in the carbonization chamber, the coke side furnace door is quickly closed, and the coal cake is pushed into the carbonization chamber together with the coal supporting plate, and then the tail baffle of the coal cake is locked at the furnace mouth, and the coal loading car pulls out the coal supporting plate, and the machine side furnace door is quickly closed to start coking. After 70 hours of coking time, coking is completed. Through observation, there is a layer of burnt white ash on the surface of the coke cake. The coke is pushed out of the carbonization chamber and connected to the coke receiving car, and then sent to the CDQ coke tank car for weighing. The total weight is about 45.2t (dry basis), the coking rate is 45.2t / (69.5t*11%)=73.0%, and the coke volatile matter V daf The coking rate of Comparative Example 1 is 1.2% lower than that of Example 1.

[0035] Comparative Example 2:

[0036] Another type of highly metamorphic anthracite is selected as the coal seam material. Its specific indicators and prices with the blending coal are shown in Table 2.

[0037] Table 2 Indexes and prices of low metamorphic coal and blended coal

[0038]

[0039] First, the Shaanxi Yulin long flame coal is crushed, and the proportion of particles less than 3mm after crushing accounts for 93%. The crushed anthracite is first sent to the small coal bunker of the coke oven coal tower through a belt; the coking coal is placed and tamped once and twice at the coal tower tamping station; after the third layer of coal laying, the anthracite coal passes through the spreading device and lays the coal layer on the surface of the coal cake from the machine side to the coke side, with a height of 40mm; then the third layer of tamping is performed to tamp the coal cake flat, and the overall coal cake height is controlled at 1150mm, with a total weight of about 69.5t (wet basis). The tamped coal cakes are sent to the coal loading car together with the coal supporting plate and transported to the carbonization chamber to be taken out of the furnace; after the coke pusher pushes out the mature coke in the carbonization chamber, the coke side furnace door is quickly closed, and the coal cakes are pushed into the carbonization chamber together with the coal supporting plate, and then the tail baffle of the coal cake is locked at the furnace mouth, the coal loading car pulls out the coal supporting plate, and the machine side furnace door is quickly closed to start coking. After 70 hours of coking time, coking is completed. Through observation, the surface of the coke cake is not burned, but the middle of the coke cake is partially black and immature. The coke is pushed out of the carbonization chamber and connected to the coke receiving car, and then sent to the CDQ coke tank car for weighing. The total weight is about 46.0t (dry basis), and the coking rate is 46.0t / (69.5t*11%)=74.3%. In addition, the volatile matter V dafAt 1.4%, it also shows that the overall coke is immature. The main reason is that the coal seam material laid in the city is anthracite, which has poor combustion and heat transfer properties, resulting in poor maturity in the middle of the coke cake, which does not meet the requirements.

Claims

1. A method for reducing coke burning loss in a horizontal heat recovery coke oven, characterized in that: The method comprises the following steps: during the process of tamping the mixed coal into coal cakes, a layer of coal is laid on the upper layer of the coal cakes, and then a tamping machine is used to compact the coal. 1) The combined coal is placed and tamped for the first time and for the second time at the coal tower tamping station; 2) After the third layer of coal is laid, the coal with low metamorphic degree is laid on the surface of the coal cake after the third layer of coal is laid from the machine side to the coke side; 3) Then the third layer of tamping is carried out, and the overall coal cake height is controlled at 1150-1160 mm, and the total weight is 67-75 tons; 4) The pounded coal cakes are sent to the carbonization chamber, and after 65 to 80 hours of coking time, the coking is completed.

2. A method for reducing coke burning loss in a horizontal heat recovery coke oven according to claim 1, characterized in that: The volatile matter V of the low metamorphic coal daf >33%, ash content A d ≤Combined coal ash content, sulfur content St<2%.

3. The method for reducing coke burning loss in a horizontal heat recovery coke oven according to claim 1, characterized in that: In the step 3), the thickness of the coal seam of the low metamorphic coal is 20 to 30 mm and the weight is 1 to 1.5 tons.

4. The method for reducing coke burning loss in a horizontal heat recovery coke oven according to claim 1, characterized in that: The proportion of particles with a diameter less than 3 mm in the low-metamorphosis coal accounts for more than 90wt%.

5. The method for reducing coke burning loss in a horizontal heat recovery coke oven according to claim 1, characterized in that: The coke yield of the obtained coke is more than 74%; the volatile matter V daf Between 1.0% and 1.3%.

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