Method for treating zinc harm by hydrogen-rich carbon circulating oxygen blast furnace

Abstract

The invention belongs to the technical field of blast furnace ironmaking, and particularly discloses a method for treating zinc harm by a hydrogen-carbon-rich circulating oxygen blast furnace, which comprises the following steps of: controlling the load of zinc entering the furnace, dynamically monitoring the zinc discharge rate, and starting graded zinc discharge operation according to the level of the discharge rate. The measures of slagging system adjustment, coal gas and oxygen injection regulation and control, top temperature management, periodic furnace temperature control, concentrated coke supplement and the like are comprehensively utilized, and upper and lower collaborative zinc discharge is achieved. According to the method, the problem of circulating enrichment of zinc in the hydrogen-rich carbon circulating oxygen blast furnace can be effectively solved, nodulation and furnace condition fluctuation are prevented, and long-term stable and smooth operation of the blast furnace and realization of a low-carbon target are guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blast furnace ironmaking, in particular to a method for treating zinc hazards of a hydrogen-rich carbon-circulation oxygen blast furnace. BACKGROUND

[0002] Traditional blast furnace ironmaking accounts for nearly 90% of the molten iron production capacity in China due to its high thermal efficiency and high production capacity, and has made great contributions to the development of national economy and human civilization. However, the carbon utilization efficiency of the blast furnace ironmaking process is low, less than 65% on average, which is the main reason for the high carbon emission of traditional blast furnace ironmaking. In order to achieve carbon emission reduction of blast furnace ironmaking, it is necessary to start from the ironmaking process and reduce carbon consumption in the ironmaking process to explore new energy-saving and carbon-reducing processes. The hydrogen-rich carbon-circulation oxygen blast furnace adopts full-oxygen smelting at tuyere, decarburization coal gas injection and hydrogen-rich coal gas to replace the traditional blast, achieving a reduction of 40% in fossil energy consumption in the whole process. The hydrogen-rich carbon-circulation oxygen blast furnace has a high smelting efficiency, and the utilization system is 30% higher than that of the traditional blast furnace. Under the same zinc load, high production capacity means that more harmful elements of zinc enter the furnace per day. At the same time, the overall top temperature of the hydrogen-rich carbon-circulation oxygen blast furnace is lower than that of the traditional blast furnace, and the output of coal gas is also lower than that of the traditional blast furnace by more than 20%. Under the conditions of low top temperature and low output of coal gas, the proportion of zinc discharged through coal gas is also lower than that of the traditional blast furnace, and the enrichment of zinc will be more obvious in the hydrogen-rich carbon-circulation oxygen blast furnace. The impact on the long-term stable operation of the furnace condition is more serious. SUMMARY

[0003] The purpose of the present application is to provide a method for treating zinc hazards of a hydrogen-rich carbon-circulation oxygen blast furnace, which realizes efficient discharge of zinc by comprehensively regulating the zinc load of the raw fuel entering the furnace, the slag making system, the coal gas injection, the top temperature management and the operation system, and guarantees the long-term stable operation of the blast furnace.

[0004] To achieve the above-mentioned purpose, the basic scheme provided by the present application is as follows: a method for treating zinc hazards of a hydrogen-rich carbon-circulation oxygen blast furnace, comprising the following steps: controlling the zinc load of the raw fuel entering the furnace to be not higher than 800g / t; dynamically monitoring and calculating the zinc discharge rate, and starting the zinc discharge measures according to the size of the zinc discharge rate; adjusting the slag basicity, increasing the coal gas injection amount, increasing the top temperature in stages, regulating the oxygen injection amount and the production capacity, implementing periodic furnace temperature control and concentrated coke replacement, and realizing collaborative zinc discharge; the calculation formula of the zinc discharge rate is: blast furnace zinc discharge rate = total zinc amount of the raw material entering the furnace / total zinc discharge amount x 100%.

[0005] Further, the slag binary basicity is controlled to be 1.0-1.08.

[0006] Further, the zinc discharge measures include a first-level zinc discharge measure, a second-level zinc discharge measure and a third-level zinc discharge measure, the first-level zinc discharge measure is started when the discharge rate is less than 80% for 10 consecutive days, the second-level zinc discharge measure is started when the zinc discharge rate is less than 75% for 5 consecutive days, and the third-level zinc discharge measure is started when the zinc discharge rate is less than 70% for 5 consecutive days.

[0007] Further, the first-level zinc discharge measure includes increasing the amount of decarburization coal gas to more than 750 m³ / t, the amount of hydrogen-rich coal gas to more than 100 m³ / t, the comprehensive amount of injection to not less than 850 m³ / t, and increasing the top temperature to more than 250 ℃ in stages for 8-12 hours.

[0008] Further, the second-level zinc discharge measure includes increasing the amount of decarburization coal gas to more than 800 m³ / t, the amount of hydrogen-rich coal gas to more than 150 m³ / t, the comprehensive amount of injection to not less than 950 m³ / t, and reducing the amount of oxygen injection at the tuyere by 20%, and correspondingly reducing the production capacity of the blast furnace by 20%.

[0009] Further, the third-level zinc discharge measure includes reducing the material line to the lower part of the shaft on the basis of the second-level zinc discharge measure, controlling the charging time so as to charge when the top temperature reaches 300 ℃, and controlling the top temperature in the range of 300-350 ℃ to concentrate the zinc discharge.

[0010] Further, during the zinc discharge, the furnace temperature control is taken as a cycle of 6-10 hours, low furnace temperature operation is maintained first, and then 1-2 batches of coke are concentratedly supplemented, and the operation is cycled.

[0011] Further, during the zinc discharge, when the fluctuation range of the cooling wall temperature exceeds 50 ℃, 1-2 batches of coke are concentratedly supplemented, and when the fluctuation range exceeds 100 ℃, 2-3 batches of coke are concentratedly supplemented.

[0012] Further, during the zinc discharge, when the tuyere appears to be born or the slag iron groove smokes seriously, 2-3 batches of coke are concentratedly supplemented, the amount of coal gas injection at the tuyere is increased to more than 850 m³ / t, and the blast temperature is increased to more than 1200 ℃.

[0013] Compared with the prior art, the application has the following advantages: 1. This invention combines the technological characteristics of a hydrogen-rich carbon-circulating oxygen blast furnace, making full use of the control of the circulating volume of top gas after decarbonization, the control of the hydrogen-rich gas injection volume, and the control of the tuyere oxygen injection volume. By adjusting the slagging system in the furnace, controlling the thermal system, and combining the lower and upper zinc discharge, this invention fully utilizes the technological characteristics of the injected gas in the hydrogen-rich carbon-circulating oxygen blast furnace to ultimately control zinc hazards. The efficiency of zinc discharge from the blast furnace is greatly improved. Actual calculations show that the zinc discharge rate of the blast furnace reaches more than 90%, and in some periods it can reach more than 100%. It can also remove the thick deposits and nodules formed by the zinc circulation enrichment in the hydrogen-rich carbon-circulating oxygen blast furnace, thereby ensuring a reasonable blast furnace operation and enabling the hydrogen-rich carbon-circulating oxygen blast furnace to achieve carbon emission reduction targets while ensuring the stable and smooth operation of the blast furnace for a long time. Detailed Implementation

[0014] The present invention will be further described in detail below through specific embodiments: A method for treating zinc hazards in a hydrogen-rich carbon-circulating oxygen blast furnace includes the following steps: The zinc load of the raw materials fed into the furnace is controlled to be no higher than 800 g / t; the zinc discharge rate is dynamically monitored and calculated, and zinc discharge measures are initiated accordingly based on the zinc discharge rate; zinc discharge is achieved by adjusting the slag basicity, increasing the gas injection volume, increasing the top temperature in stages, regulating the oxygen injection volume and production capacity, and implementing periodic furnace temperature control and centralized coking. The formula for calculating the zinc discharge rate is: blast furnace zinc discharge rate = total zinc in the charge / total zinc discharged × 100%; the binary basicity of the slag is controlled between 1.0 and 1.08; zinc discharge measures include primary zinc discharge measures, secondary zinc discharge measures, and tertiary zinc discharge measures.

[0015] When the discharge rate is below 80% for 10 consecutive days, the first-level zinc discharge measures will be initiated, specifically including increasing the decarbonized gas injection rate to 750m³. 3 / t or more, hydrogen-rich coal gas injection rate up to 100m³ 3 / t or above, with a comprehensive injection volume of not less than 850m³ 3 / t, and gradually increase the top temperature to above 250℃ for 8-12 hours.

[0016] When the zinc removal rate is below 75% for five consecutive days, secondary zinc removal measures are initiated, specifically including increasing the decarbonized gas injection rate to 800m³. 3 / t or more, hydrogen-rich coal gas injection rate up to 150m³ 3 / t or above, with a comprehensive injection volume of not less than 950m³ 3 / t, and reduce the oxygen injection volume at the tuyeres by 20%, thereby reducing the blast furnace capacity by 20%.

[0017] When the zinc discharge rate is below 70% for 5 consecutive days, a three-level zinc discharge measure is initiated. Specifically, based on the two-level zinc discharge measure, the material line is lowered to the bottom of the furnace body, the timing of material feeding is controlled so that the top temperature reaches 300℃ before adding material, and the top temperature is controlled within the range of 300-350℃ for concentrated zinc discharge.

[0018] In addition, during zinc removal, furnace temperature control is carried out in 6-10 hour cycles. First, maintain a low furnace temperature, then replenish coke 1-2 times, repeating this cycle. If the cooling wall temperature fluctuates by more than 50°C during zinc removal, replenish coke 1-2 times; if it exceeds 100°C, replenish coke 2-3 times. If there is significant tuyere settling or severe smoke from the slag and iron trough, replenish coke 2-3 times and increase the tuyere gas injection rate to 850 m³ / h. 3 / t or above, the air temperature is increased to above 1200℃.

[0019] An example of Baosteel using the above method in a 400 cubic meter hydrogen-rich carbon-circulating oxygen blast furnace is as follows: Example 1 The zinc content in the raw materials and fuels, as well as the zinc content in the gravity dust and wet dust sludge, is monitored daily to calculate the zinc enrichment. If the zinc removal rate is less than 90%, the following zinc removal operation is initiated: Specifically as follows: By adjusting the blast furnace charge structure, reducing the amount of high-zinc sinter, and increasing the amount of low-zinc pellets, the zinc load of the blast furnace was reduced to 600g / t.

[0020] The decarbonized gas injection rate was increased from 650 m³ / h. 3 / t, increased to 750m 3 / t, while increasing the hydrogen-rich gas injection rate to 150m³. 3 / t, reducing the blast furnace coke ratio to below 320kg / t, the pulverized coal injection ratio to 50kg / t, fossil energy consumption to 370kg / t, and the blast furnace sulfur load to 3.5kg / t.

[0021] Due to the reduced sulfur load, the binary basicity (CaO / SiO2) of the upper furnace charge was adjusted to 1.05 times, which created favorable conditions for slag alkali discharge.

[0022] After the above operations were completed and continued for 3 days, zinc was collected from raw materials and fuels, as well as zinc from gravity dust collectors and wet dust collector sludge. It was found that the zinc discharge rate reached 100%.

[0023] Example 2 The zinc content in the raw materials and fuels, as well as the zinc content in the gravity dust and wet dust sludge, is monitored daily to calculate the zinc enrichment. The zinc removal rate is 85%, and has been above 5% for more than 5 consecutive days. Therefore, the following zinc removal procedures are initiated: By adjusting the blast furnace charge structure, reducing the amount of high-zinc sinter, and increasing the amount of low-zinc pellets, the zinc load of the blast furnace was reduced to 600g / t.

[0024] The decarbonized gas injection rate was increased from 650 m³ / h. 3 / t, increased to 700m 3 / t, while increasing the hydrogen-rich gas injection rate to 100m³. 3 / t, reduce the blast furnace coke ratio to below 350kg / t, reduce the pulverized coal injection ratio to 50kg / t, reduce fossil energy consumption to 400kg / t, reduce the blast furnace sulfur load to 3.8kg / t, control the oxygen content at the tuyeres, reduce blast furnace capacity by 20%, and control the top temperature at 200-250℃.

[0025] Due to the reduced sulfur load, the binary basicity (CaO / SiO2) of the upper furnace charge was adjusted to 1.03 times, which created favorable conditions for slag alkali discharge.

[0026] The furnace temperature is controlled in 6-hour cycles. For 6 hours, the blast furnace temperature is controlled at a low level, between 1390-1420℃, and the silicon content of the molten iron is controlled at 0.2-0.4%. The low temperature is conducive to zinc discharge from the blast furnace slag. After 6 hours, a batch of coke is added to raise the furnace temperature, which is then maintained for 4 hours. The furnace temperature is then maintained at a lower level. This process is repeated for 3 days. Zinc from the raw materials and fuels, as well as zinc from gravity dust collector ash and wet dust collector sludge, was collected. It was found that the zinc discharge rate reached 100%.

[0027] Example 3 The zinc content in the raw materials and fuels, as well as the zinc content in the gravity dust and wet dust sludge, is monitored daily to calculate the zinc enrichment. The zinc removal rate is only 70%, and this has been ongoing for more than 5 consecutive days. Therefore, the following zinc removal procedures have been initiated: Specifically as follows: By adjusting the blast furnace charge structure, reducing the amount of high-zinc sinter, and increasing the amount of low-zinc pellets, the zinc load of the blast furnace was reduced to 600g / t.

[0028] The decarbonized gas injection rate was increased from 650 m³ / h. 3 / t, increased to 800m 3 / t, while increasing the hydrogen-rich gas injection rate to 150m³. 3 / t, reduce the blast furnace coke ratio to below 300kg / t, control the pulverized coal injection ratio to 50kg / t, reduce fossil energy consumption to 350kg / t, and reduce the blast furnace sulfur load to 3.0kg / t.

[0029] The binary basicity (CaO / SiO2) of the upper furnace charge was adjusted to 1.01 times, which created favorable conditions for alkali discharge from the slag.

[0030] The oxygen level at the tuyere is reduced by 20%. The feeding is controlled, and the material is added only when the top temperature reaches 250℃. The material line is gradually lowered to the lower part of the furnace body. Water is pumped from the top of the furnace to keep the upper limit of the top temperature below 350℃.

[0031] During the zinc discharge process, it was discovered that the tuyeres were experiencing a drop in temperature, and the temperature of the slag and iron was significantly lower than normal, with a large amount of smoke emanating from the surface of the slag and iron. Immediately, three batches of coke were added to the furnace, and the furnace temperature was raised.

[0032] Sixteen to twenty-four hours after the above zinc removal operation, zinc was collected from raw materials and fuels, as well as harmful zinc elements from gravity dust and wet dust removal sludge. It was found that the zinc removal rate reached 100%.

[0033] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for treating zinc hazards in a hydrogen-rich carbon-circulating oxygen blast furnace, characterized in that, Includes the following steps: Control the zinc load of raw materials entering the furnace to not exceed 800g / t; dynamically monitor and calculate the zinc discharge rate, and initiate zinc discharge measures according to the size of the zinc discharge rate; achieve coordinated zinc discharge by adjusting slag alkalinity, increasing gas injection volume, increasing top temperature in stages, regulating oxygen injection volume and production capacity, and implementing periodic furnace temperature control and centralized coking.

2. The method for treating zinc hazards in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The binary basicity of the slag is controlled between 1.0 and 1.

08.

3. The method for treating zinc hazards in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The zinc removal measures include primary, secondary, and tertiary zinc removal measures. Primary zinc removal measures are initiated when the zinc removal rate is below 80% for 10 consecutive days; secondary zinc removal measures are initiated when the zinc removal rate is below 75% for 5 consecutive days; and tertiary zinc removal measures are initiated when the zinc removal rate is below 70% for 5 consecutive days.

4. The method for treating zinc hazards in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 3, characterized in that, The primary zinc removal measures include increasing the decarbonization gas injection rate to 750 m³. 3 / t or more, hydrogen-rich coal gas injection rate up to 100m³ 3 / t or above, with a comprehensive injection volume of not less than 850m³ 3 / t, and gradually increase the top temperature to above 250℃ for 8-12 hours.

5. The method for treating zinc hazards in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 3, characterized in that, The secondary zinc removal measures include increasing the decarbonized gas injection rate to 800m³. 3 / t or more, hydrogen-rich coal gas injection rate up to 150m³ 3 / t or above, with a comprehensive injection volume of not less than 950m³ 3 / t, and reduce the oxygen injection volume at the tuyeres by 20%, thereby reducing the blast furnace capacity by 20%.

6. The method for treating zinc hazards in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 5, characterized in that, The three-stage zinc removal measures include, on the basis of the two-stage zinc removal measures, lowering the material line to the lower part of the furnace body, controlling the timing of feeding so that the top temperature reaches 300°C before feeding, and controlling the top temperature within the range of 300-350°C for centralized zinc removal.

7. The method for treating zinc hazards in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, During zinc removal, furnace temperature is controlled in 6-10 hour cycles. First, maintain a low furnace temperature, then replenish coke in 1-2 batches, and repeat the cycle.

8. The method for treating zinc hazards in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, During zinc removal, when the temperature fluctuation of the cooling wall exceeds 50°C, 1-2 batches of coke are replenished in a concentrated manner; when it exceeds 100°C, 2-3 batches of coke are replenished in a concentrated manner.

9. The method for treating zinc hazards in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, During zinc discharge, if there is excessive steaming at the tuyeres or severe smoke from the slag and iron ditch, replenish the coke supply in 2-3 batches and increase the tuyeres gas injection rate to 850m³. 3 / t or above, the air temperature is increased to above 1200℃.