A method for smelting titanium slag to stably produce high-concentration coal gas

Abstract

The present invention relates to a method for smelting titanium slag to stably produce high-concentration coal gas, and the method comprises the following steps: before charging titanium-bearing blast furnace slag into an electric furnace, adding a predetermined amount of a reducing agent; when the CO concentration in the raw coal gas rapidly rises, starting to add the remaining amount of the reducing agent into the electric furnace; maintaining the relatively stable active power input to the electric furnace, and timely fine-tuning the adding speed of the remaining amount of the reducing agent according to the change trend of the CO concentration. In the reducing agent adding stage of the present invention, the CO concentration in the coal gas always remains above 35%. Among them, the time continuously and stably above 40% is greater than 105 min (after the addition of the reducing agent is completed, the system will still continue to react for a period of time, and the CO will continue to remain at a high concentration), and the time continuously and stably above 45% is greater than 90 min. The designed method for smelting titanium slag of the present invention can improve the utilization efficiency of carbonaceous reducing agents, reduce the consumption of carbonaceous fuels in the whole production process, and is beneficial to carbon emission reduction.

Description

Technical Field

[0001] The present invention belongs to the technical field of titanium slag smelting, and particularly relates to a titanium slag smelting method for stably producing high-concentration gas. Background Art

[0002] During the production process of smelting titanium-bearing blast furnace slag using an electric furnace, the raw gas generated can be processed through capture, cooling, dust removal, and purification to obtain high-quality gas. The recovered gas can be pressurized and burned and then reused for drying the materials in the next production process. Therefore, stably producing gas with a high CO concentration during the electric furnace smelting can increase the calorific value of the gas, reduce the consumption of other auxiliary fuels in the next process, thereby reducing production costs and promoting carbon emission reduction. The complexity of the electrothermal conversion process and the metallurgical reaction itself has caused the CO concentration in the gas generated during smelting to be consistently low and fluctuate greatly for a long time, resulting in insufficient gas recovery and low calorific value of the gas. Summary of the Invention

[0003] To overcome the deficiencies of existing detection methods, the present invention designs a titanium slag smelting method for stably producing high-concentration gas. Based on continuous exploration and summary of smelting operation methods, the method has successfully achieved ensuring the smelting target while maintaining the CO concentration in the gas generated during smelting at a high value for a long time, creating excellent conditions for gas recovery, reducing the consumption of other auxiliary fuels, and reducing production costs.

[0004] The technical solution adopted by the present invention is as follows: A titanium slag smelting method for stably producing high-concentration gas, the method comprising the following steps:

[0005] Before charging titanium-bearing blast furnace slag into the electric furnace, a predetermined amount of reducing agent is added;

[0006] When the CO concentration in the raw gas rises rapidly, the remaining amount of reducing agent is added to the electric furnace;

[0007] Maintain the active power input to the electric furnace relatively stable, and timely fine-tune the addition speed of the remaining amount of reducing agent according to the change trend of the CO concentration.

[0008] Further, the fixed carbon content in the reducing agent is ≥ 75 wt%.

[0009] Further, the reducing agent is one or more mixtures of carbon-containing materials.

[0010] Further, the amount value of the predetermined amount of reducing agent is 20 - 75 kg / t 高炉渣 ; the amount value of the remaining amount of reducing agent is 80 - 120 kg / t 高炉渣 , t 高炉渣 represents the addition amount of the reducing agent determined according to the weight of the charged titanium-bearing blast furnace slag.

[0011] Further, the amount of the reducing agent in the predetermined amount is 40-60 kg / t 高炉渣 ; the amount of the reducing agent in the remaining amount is 90-110 kg / t 高炉渣 .

[0012] Further, the rapid increase in the CO concentration in the raw gas is: the rising rate of the CO concentration is greater than or equal to 1.25% CO / min.

[0013] Further, the time to start adding the reducing agent in the remaining amount is 20-40 min of smelting.

[0014] Further, when starting to add the reducing agent in the remaining amount, the CO concentration is 30%-40%.

[0015] Further, maintaining the relatively stable active power input to the electric furnace includes matching the electrode insertion depth, the transformer gear position, or the adding speed of the reducing agent in the remaining amount.

[0016] Further, adjusting the adding speed of the reducing agent in the remaining amount in a timely manner according to the change trend of the CO concentration is as follows:

[0017] When the CO concentration shows a downward trend, reduce the adding speed of the reducing agent in the remaining amount; when the CO concentration shows an upward trend, increase the adding speed of the reducing agent in the remaining amount.

[0018] Further, the adding speed of the reducing agent in the remaining amount is fast first and then slow,

[0019] When the time t0 is from 0 min to the time t1 is between 60-70 min, the adding speed of the reducing agent in the remaining amount is 90-120 kg / min;

[0020] When the time t1 is from 60-70 min to the end time t2 of adding, the adding speed of the reducing agent in the remaining amount is 10-28 kg / min.

[0021] Further, when adding the reducing agent in the remaining amount at the time t0-t1, the change range of the transformer gear position does not exceed 5 gears, and gradually raise the matching electrode insertion depth; when adding the reducing agent in the remaining amount at the time t1-t2, the transformer gear position gradually decreases, and the matching electrode insertion depth remains unchanged.

[0022] Further, the duration from the time t0 to t2 is 90-125 min.

[0023] Further, the average adding speed of the reducing agent in the remaining amount within the time period from t0 to t2 is greater than or equal to 50 kg / min.

[0024] The present invention has the following beneficial effects:

[0025] (1) During the reducing agent addition stage, the CO concentration in the gas always remains above 35%. Among them, the time when it continuously and stably remains above 40% is greater than 105 min (after the addition of the reducing agent ends, the system will continue to react for some time, and CO will continue to remain at a relatively high concentration), and the time when it continuously and stably remains above 45% is greater than 90 min. The proportions of the time when the CO concentration is stable above 40% and 45% in the total smelting time reach 72% and 62% or more respectively;

[0026] (2) The maximum value of the CO concentration in the gas can reach above 55%;

[0027] (3) Based on the reducing agent addition stage duration of 100 min, the average CO concentration in the gas is 45% (gas calorific value 1500 kCal / Nm 3 ), and the gas recovery volume is 10000 Nm 3 / h for calculation, the heat of the gas is about 2.5×10 7 kCal, where the heat of the gas is calculated as 1500×10000×(100 / 60) = 2.5×10 7 kCal, which is equivalent to 3570.6 kg of standard coal (standard coal calorific value 7001.6 kCal / kg);

[0028] (4) Improving the utilization efficiency of carbonaceous reducing agents and reducing the consumption of carbonaceous fuels in the entire production process are beneficial to carbon reduction and emission reduction.

[0029] Other features and advantages of the present invention will be described in the subsequent specification, and part of them will become obvious from the specification, or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the specification, claims, and drawings. Brief Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0031] Figure 1 Shows the change curve of the CO concentration with time in Embodiment 1 of the present invention;

[0032] Figure 2 Shows the change curve of the CO concentration with time in Embodiment 2 of the present invention. Detailed Embodiments

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] A titanium slag smelting method for stably producing high-concentration coal gas, the method comprising the following steps:

[0035] Before charging the titanium-bearing blast furnace slag into the electric furnace, a predetermined amount of reducing agent is added;

[0036] When the CO concentration in the raw coal gas rises rapidly, the remaining amount of reducing agent is started to be added into the electric furnace;

[0037] Maintain the relative stability of the active power input to the electric furnace, and timely fine-tune the adding speed of the remaining amount of reducing agent according to the change trend of the CO concentration.

[0038] The following will introduce the specific steps of the above titanium slag smelting method for stably producing high-concentration coal gas through specific embodiments.

[0039] Example 1

[0040] After the previous furnace charge is completed, 3390 kg of coke powder (3390 kg / 68.5 t = 49.5 kg / t 高炉渣 , fixed carbon content 84.5 wt%) is added into the electric furnace, and then 68.5 t of titanium-bearing blast furnace slag is charged. The CO concentration in the raw coal gas rises from 0 to 25% within 15 min and continues to rise rapidly. The CO concentration reaches 37% at 27 min of smelting, and the remaining coke powder (a total of 6156 kg, 6156 / 68.5 = 89.9 kg / t 高炉渣 ) is started to be added into the furnace. The average adding speed of the remaining amount of coke powder in the early stage of 60 min is 101.7 kg / min. During this period, the average active power input to the smelting is maintained at about 28 MW by maintaining the transformer tap (the transformer tap is controlled at 1-2 gears), gradually reducing the matching electrode insertion depth (the matching electrode insertion depth is lifted by about 400 mm), and adjusting the instantaneous adding speed of the coke powder; when the adding time of the remaining amount of coke powder is 60 - 113 min, the average adding speed is 25.5 kg / min. During this period, the average active power input to the smelting is maintained at about 24.8 MW by maintaining the matching electrode insertion depth basically unchanged, gradually reducing the transformer tap (gradually adjusted from 2 gears to 9 gears), and controlling the instantaneous adding speed of the coke powder.

[0041] In summary, in Example 1, the average addition rate of the remaining coke powder (average addition rate of the remaining coke powder = remaining coke powder / addition duration) was 54.5 kg / min, and the addition duration was 113 min. Figure 1 Fig. Figure 1 shows the change curve of CO concentration over time in Example 1 of the present invention. Through the electric furnace smelting method in Example 1, the time when the CO concentration in the smelting-produced gas is above 40% is 118 min, accounting for 82.5% of the total smelting time; the time when the CO concentration is above 45% is 113 min, accounting for 79% of the total smelting time; the maximum value of the CO concentration is 64%. It can be seen that the CO concentration can be stably maintained at a relatively high value for a long time, and at the same time, the smelting target can be achieved.

[0042] Example 2

[0043] After the previous furnace charge ended, 3261 kg of coke powder (fixed carbon content 84.5%) was added into the electric furnace, and then 65.4 t of titanium-bearing blast furnace slag was charged. The CO concentration in the raw gas rose from 0 to 25% within 10 min and continued to rise rapidly. When smelting for 37 min, the CO concentration reached 32%, and then the remaining coke powder (a total of 6285 kg) began to be added into the furnace. The average addition rate of the remaining coke powder in the early stage of 61 min was 98.9 kg / min. By maintaining the transformer gear position (the transformer gear position was controlled at gears 1 - 4), gradually reducing the matching electrode insertion depth (the matching electrode insertion depth was lifted by about 325 mm), and adjusting the instantaneous addition rate of the coke powder, the average input active power of the smelting was maintained at about 28 MW; the average addition rate of the remaining coke powder from 61 to 95 min was 16.2 kg / min. By maintaining the electrode insertion depth basically unchanged, gradually reducing the transformer gear position (gradually adjusted from gear 4 to gear 10), and controlling the instantaneous addition rate of the coke powder, the average input active power of the smelting was maintained at about 26 MW.

[0044] In summary, in Example 2, the average addition rate of the remaining coke powder (average addition rate of the remaining coke powder = remaining coke powder / addition duration) was 66.2 kg / min, and the addition duration was 95 min. Figure 2 Fig. Figure 2 shows the change curve of CO concentration over time in Example 2 of the present invention. Through the electric furnace smelting method in Example 2, the time when the CO concentration in the smelting-produced gas is above 40% is 109 min, accounting for 72.2% of the total smelting time; the time when the CO concentration is above 45% is 94 min, accounting for 62.3% of the total smelting time; the maximum value of the CO concentration is 58%. It can be seen that the CO concentration can be stably maintained at a relatively high value for a long time, and at the same time, the smelting target can be achieved.

[0045] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for smelting titanium slag to stably produce high-concentration coal gas, the method comprising the following steps: Before charging the blast furnace slag containing titanium into the electric furnace, a predetermined amount of reducing agent is added; When the CO concentration in the raw coal gas rises rapidly, the remaining amount of reducing agent is started to be added into the electric furnace; Maintain the relatively stable active power input to the electric furnace, and timely fine-tune the addition speed of the remaining amount of reducing agent according to the change trend of the CO concentration; Among them, the quantity value of the predetermined amount of reducing agent is 20 to 75 kg / t 高炉渣 ; the quantity value of the remaining amount of reducing agent is 80 to 120 kg / t 高炉渣 , t 高炉渣 means that the addition amount of the reducing agent is determined according to the weight of the titanium-bearing blast furnace slag charged; Among them, the rapid increase in the CO concentration in the raw coke oven gas is that the rising speed of the CO concentration is greater than or equal to 1.25% CO / min; Among them, maintaining the relatively stable active power input to the electric furnace includes matching the electrode insertion depth, transformer gear position or the addition speed of the remaining amount of reducing agent; Among them, the addition speed of the remaining amount of reducing agent is fast first and then slow, When the time t0 is between 0 min and the time t1 is 60 - 70 min, the addition speed of the remaining amount of reducing agent is 90 - 120 kg / min; When the time t1 is between 60 - 70 min and the end time t2 of the addition, excluding t1, the addition speed of the remaining amount of reducing agent is 10 - 28 kg / min; Among them, during the addition time t0 - t1 of the remaining amount of reducing agent, the change range of the transformer gear position does not exceed 5 gears, and the electrode insertion depth is gradually increased to match; during the addition time t1 - t2 of the remaining amount of reducing agent, the transformer gear position is gradually decreased, and the electrode insertion depth remains unchanged.

2. The method according to claim 1, wherein, The fixed carbon content in the reducing agent is ≥ 75 wt%.

3. The method according to claim 1 or 2, wherein The reducing agent is one or more mixtures of carbon-containing materials.

4. The method according to claim 1, wherein The quantity value of the predetermined amount of reducing agent is 40 to 60 kg / t 高炉渣 ; The quantity value of the remaining amount of reducing agent is 90 to 110 kg / t 高炉渣 .

5. The method according to claim 1, wherein The time to start adding the remaining amount of reducing agent is 20 - 40 min of smelting.

6. The method according to claim 5, wherein, When starting to add the remaining amount of reducing agent, the CO concentration is 30% - 40%.

7. The method according to claim 1, wherein Timely fine-tuning the addition speed of the remaining amount of reducing agent according to the change trend of the CO concentration is: When the CO concentration shows a downward trend, reduce the addition speed of the remaining amount of reducing agent; when the CO concentration shows an upward trend, increase the addition speed of the remaining amount of reducing agent.

8. The method according to claim 1, wherein, The duration of the time t0 - t2 is 90 - 125 min.

9. The method according to claim 8, wherein The average addition speed of the remaining amount of reducing agent within the time period t0 - t2 is greater than or equal to 50 kg / min.

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