Method for improving coal gas recovery quality through dry dedusting

Abstract

The invention discloses a method for improving coal gas recovery quality through dry dedusting, which comprises the following steps: S1, setting and dynamically adjusting the rotating speed parameter of a fan aiming at each stage of converter smelting, and controlling the fan to operate according to different operation links and blowing time periods in the smelting process and the set rotating speed parameter and time parameter; s2, raw material preparation and parameter regulation and control are carried out, components, temperature and charging quantity parameters of molten iron entering a furnace are set and controlled, and meanwhile the charging quantity and charging mode parameters of waste steel are set and regulated and controlled; s3, according to the silicon element content of the molten iron, correspondingly setting and controlling a furnace mouth micro differential pressure parameter; s4, in the main blowing smelting stage, oxygen supply flow parameters are matched, set and controlled according to the silicon element content of the molten iron; s5, auxiliary control parameter setting and measures are implemented, wherein the auxiliary control parameters comprise a smoke hood operation control parameter, an evaporative cooling system medium adjustment parameter, a gas recovery program optimization parameter and a fan rotating speed control mode configuration parameter; and S6, after smelting is finished, the recovery average value of CO in the coal gas is recorded. According to the method for improving the coal gas recovery quality through dry dedusting, the average CO value of coal gas recovery is larger than or equal to 55%, the heat value is high, the coal gas quality is stably improved during continuous production of a converter, and the cost reduction and efficiency improvement effects are obvious.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel smelting technology. Specifically, this invention relates to a method for improving the quality of coal gas recovery through dry dust removal. Background Technology

[0002] Converter gas is a byproduct of converter steelmaking, and its recovery quality directly affects the economic and environmental benefits of enterprises. In the early stages of converter blowing, negative pressure often forms inside the furnace, drawing in large amounts of air. This results in excessively high oxygen content due to CO combustion in the flue gas. Similarly, in the later stages of smelting, the carbon content in the molten steel is very low, and the amount of furnace gas produced is also small, creating a huge negative pressure in the furnace that not only draws in air but can sometimes even bring oxygen back into the furnace gas. Furthermore, the dust removal fans in the pre- and post-smelting stages are prone to surge due to insufficient airflow, posing a potential hazard to the fans. The large amount of air drawn in, on the one hand, reduces the CO content in the furnace gas due to combustion, and on the other hand, increases the O2 content in the furnace gas. Both of these factors affect the recovery quality of converter gas.

[0003] Dry dust removal is a relatively new gas recovery process, but its quality is generally lower than that of OG (Oil-Gas) gas recovery. Currently, there are two mature methods for increasing gas recovery in converter dry dust removal: one is timely hood lowering, controlling the positive pressure difference between the hood and the furnace mouth, lowering the standard for recovered CO content, and making corresponding improvements in smelting operations, equipment maintenance, and gas collection methods. These measures do increase the amount of gas recovered, but the quality of the recovered gas is not high. The second method results in lower CO content and reduced calorific value in the recovered converter gas, leading to resource waste and failing to maximize enterprise profits. However, neither method offers a mature solution for improving the quality of recovered gas.

[0004] Chinese Patent Application No. 201710740655.6 discloses a method for effectively improving the quality and quantity of converter gas recovery. This method focuses on using the OG method to improve the quantity and quality of gas recovery. Specifically, converter gas is introduced into the flue at a suitable location on the air inlet side of the converter dust collector fan. This avoids the formation of negative pressure in the furnace during the early and late stages of converter smelting due to the large fan suction and small gas generation, which would draw in a large amount of air. Converter gas can be recovered throughout the converter blowing process, thereby significantly improving the amount and quality of converter gas recovery.

[0005] This invention provides a method for improving the quality of coal gas recovery through dry dust removal, specifically concerning how to achieve stable control of high-quality coal gas recovery in converters under uninterrupted production conditions, thereby improving the quality of coal gas recovery. Summary of the Invention

[0006] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a method for improving the quality of coal gas recovery through dry dust removal, with the purpose of achieving stable control of high-quality coal gas recovery in converters under uninterrupted production conditions, thereby improving the quality of coal gas recovery.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for improving the quality of coal gas recovery through dry dust removal, comprising the following steps:

[0008] S1. Set and dynamically adjust the fan speed parameters for each stage of converter smelting. Control the fan operation according to the set speed and time parameters based on different operation links and blowing periods in the smelting process.

[0009] S2. Prepare raw materials and adjust parameters, set and control the composition, temperature and charging amount of molten iron entering the furnace, and set and adjust the charging amount and charging method of scrap steel.

[0010] S3. Based on the silicon content of the molten iron, set and control the furnace mouth differential pressure parameters accordingly;

[0011] S4. During the main blowing smelting stage, the oxygen supply flow rate parameters are matched, set, and controlled according to the silicon content of the molten iron.

[0012] S5. Implement auxiliary control parameter settings and measures, including fume hood operation control parameters, evaporative cooling system medium adjustment parameters, gas recovery program optimization parameters, and fan speed control mode configuration parameters;

[0013] S6. After smelting, record the average CO recovery value in the coal gas.

[0014] In step S1, the blower speed is set to 400-440 r / min when waiting for the converter, 800-840 r / min when tapping iron, 1140-1180 r / min when blowing is interrupted, 780-820 r / min after blowing is completed, 730-770 r / min when tapping steel, 820-860 r / min when splashing slag to protect the furnace, and 580-620 r / min when tapping slag.

[0015] In step S1, the multiple blowing periods include the first to ninth blowing periods, the blowing feeding period, the blowing auxiliary lance measurement period, the cup valve switching period, the period before cup valve retraction, the period after blowing interruption, and the period of slightly high positive pressure. The fan speed and time control for each period are as follows:

[0016] First blowing period: time set to 60s, speed set to 850-870r / min;

[0017] Second blowing period: time set to 120s, speed set to 820-840r / min;

[0018] Third blowing period: time set to 90s, speed set to 840-860r / min;

[0019] Fourth blowing stage: time set to 30s, speed set to 1065-1085r / min;

[0020] Fifth blowing stage: Time set to 120s, rotation speed set to 1075-1095r / min;

[0021] The sixth blowing period: the time is set to 180s, and the rotation speed is set to 1070-1090r / min;

[0022] The seventh blowing stage: the time is set to 90 seconds, and the rotation speed is set to 1070-1090 r / min;

[0023] Eighth blowing stage: time set to 120s, speed set to 1080-1100r / min;

[0024] Ninth blowing stage: time set to 900s, speed set to 1090-1110r / min;

[0025] Blowing and feeding period: time set to 60s, rotation speed set to 0+20r / min;

[0026] Measurement period for the blowing lance: time set to 120s, rotation speed set to 0-+20r / min;

[0027] Cup valve switching time: time set to 90s, speed set to +30-+50r / min;

[0028] Before the cup valve is cut off and retracted: the time is set to 30 seconds, and the rotation speed is set to 1060-1080 r / min;

[0029] Period after blowing interruption: time set to 120s, speed set to 1090-1110r / min;

[0030] During periods of excessively high positive pressure: the time is set to 180 seconds, and the rotation speed is set to 1120-1140 r / min.

[0031] In step S2, the molten iron composition is specifically: Si 0.10%wt%~0.70%wt%, P≤0.14wt%, [C]>4.5wt%.

[0032] In step S2, the molten iron temperature is set to 1250-1450℃; the total loading amount is set to 168±3t; the molten iron weight is set to 130-150t; and the scrap steel weight is set to 20-35t.

[0033] In step S3, the furnace mouth differential pressure control parameters are as follows under different silicon content conditions in the molten iron:

[0034] When the silicon content of molten iron is 0.1% < Si ≤ 0.2%, the differential pressure is set to 10-30 Pa.

[0035] When the silicon content of molten iron is 0.2% < Si ≤ 0.3%, the differential pressure is set to 20-40 Pa.

[0036] When the silicon content of molten iron is 0.3% < Si ≤ 0.4%, the differential pressure is set to 30-50 Pa.

[0037] When the silicon content of molten iron is 0.4% < Si ≤ 0.5%, the differential pressure is set to 40-60 Pa.

[0038] When the silicon content of molten iron is 0.5% < Si ≤ 0.6%, the differential pressure is set to 50-70 Pa.

[0039] In step S4, the oxygen supply flow control parameters are as follows under different iron silicon content conditions:

[0040] When the silicon content of molten iron is 0.1% < Si ≤ 0.2%, the oxygen supply flow rate should be set to 33,000-35,000 Nm³. 3 / h;

[0041] When the silicon content of molten iron is 0.2% < Si ≤ 0.3%, the oxygen supply flow rate should be set to 35,000-37,000 Nm³. 3 / h;

[0042] When the silicon content of molten iron is 0.3% < Si ≤ 0.4%, the oxygen supply flow rate should be set to 37,000-39,000 Nm³. 3 / h;

[0043] When the silicon content of molten iron is 0.4% < Si ≤ 0.5%, the oxygen supply flow rate should be set to 39000-41000 Nm. 3 / h;

[0044] When the silicon content of molten iron is 0.5% < Si ≤ 0.6%, the oxygen supply flow rate should be set to 41000-43000 Nm. 3 / h.

[0045] In step S5, the implementation of auxiliary control specifically includes:

[0046] The fume hood is automatically raised and lowered according to the oxygen supply rhythm of the converter.

[0047] The spray gun medium of the evaporative cooler has been replaced with steam instead of nitrogen.

[0048] In the gas recovery process, the recovery is terminated after a preset time delay following the converter shutdown.

[0049] Multiple fan speed control templates are configured according to oxygen supply intensity and production rhythm, and are adapted to the furnace mouth micro differential pressure control.

[0050] In step S2, when a leak is detected, an emergency response procedure is executed, including immediately raising the lance and initiating nitrogen purging, with the nitrogen purging flow rate set to 40,000-45,000 Nm. 3 / h.

[0051] The dry dust removal method of the present invention for improving the quality of coal gas recovery has the following beneficial effects:

[0052] (1) The average CO value of the recovered gas is ≥55%, and the calorific value is high. It can achieve stable improvement in gas quality during continuous production in the converter, and the cost reduction and efficiency improvement effects are obvious.

[0053] (2) After the fan is pre-speeded up by 10%, the recovery time is delayed by 30 seconds. Based on the increase in the amount of gas recovered, the quality is also improved by 10%.

[0054] (3) Different furnace mouth differential pressure and fully automatic hood lowering control are adopted to significantly improve the gas concentration during the blowing period. Detailed Implementation

[0055] The following description of the embodiments provides a more detailed explanation of the specific implementation of the present invention, with the aim of helping those skilled in the art to have a more complete, accurate, and in-depth understanding of the inventive concept and technical solution of the present invention, and facilitating its implementation.

[0056] This invention provides a method for improving the quality of coal gas recovery through dry dust removal, comprising the following steps:

[0057] S1. Set and dynamically adjust the fan speed parameters for each stage of converter smelting. Control the fan operation according to the set speed and time parameters based on different operation links and blowing periods in the smelting process.

[0058] S2. Prepare raw materials and adjust parameters, set and control the composition, temperature and charging amount of molten iron entering the furnace, and set and adjust the charging amount and charging method of scrap steel.

[0059] S3. Based on the silicon content of the molten iron, set and control the furnace mouth differential pressure parameters accordingly;

[0060] S4. During the main blowing smelting stage, the oxygen supply flow rate parameters are matched, set, and controlled according to the silicon content of the molten iron.

[0061] S5. Implement auxiliary control parameter settings and measures, including fume hood operation control parameters, evaporative cooling system medium adjustment parameters, gas recovery program optimization parameters, and fan speed control mode configuration parameters;

[0062] S6. After smelting, record the average CO recovery value in the coal gas.

[0063] Specifically, the purpose of this invention is to provide a method for improving the quality of gas recovery in converter dry dust removal. By optimizing process operation and dynamically controlling the fan speed at different stages, a stable control of the average CO concentration in the converter gas per furnace can be achieved, reaching over 60%. This primarily addresses the technical problems of low gas recovery quality, complex molten iron conditions, and stringent requirements for the timing of raw material addition in existing technologies, achieving stable and efficient converter gas recovery while significantly reducing production costs.

[0064] The main innovations in this invention are as follows:

[0065] (1) A method for improving the quality of coal gas recovery by dry dust removal is provided, which achieves high-quality coal gas recovery under the condition of uninterrupted production of converter;

[0066] (2) A method for matching the silicon content of molten iron with the temperature of molten iron is provided to improve the quality of coal gas recovery;

[0067] (3) By adopting the method of dynamically adjusting the blower at different stages of blowing, the quality of gas recovery at different stages is significantly improved, and the average CO concentration of gas per furnace reaches more than 55%.

[0068] (4) After the gas recovery fan speed is increased by 10% at the end of the recovery period, the recovery time is delayed by 30 seconds. Based on the increase in the amount of gas recovered, the quality is also improved by 10%.

[0069] In this embodiment of the invention, in step S1 above, the blower speed is set to 400-440 r / min when the converter is waiting, 800-840 r / min when tapping iron, 1140-1180 r / min when blowing is interrupted, 780-820 r / min after blowing is completed, 730-770 r / min when tapping steel, 820-860 r / min when splashing slag to protect the furnace, and 580-620 r / min when tapping slag, as shown in Table 1.

[0070] In this embodiment of the invention, in step S1 above, the multiple blowing periods include the first blowing period to the ninth blowing period, the blowing feeding period, the blowing auxiliary gun measurement period, the cup valve switching period, the period before the cup valve is cut off and recovered, the period after the blowing is interrupted, and the period of slightly high positive pressure. Under different blowing periods, the fan speed is controlled according to the requirements of Table 1.

[0071] Table 1 Control of Fan Speed ​​and Time Before Smelting

[0072]

[0073] In step S1 above, the fan speed and time control for each time period are as follows:

[0074] First blowing period: time set to 60s, speed set to 850-870r / min;

[0075] Second blowing period: time set to 120s, speed set to 820-840r / min;

[0076] Third blowing period: time set to 90s, speed set to 840-860r / min;

[0077] Fourth blowing stage: time set to 30s, speed set to 1065-1085r / min;

[0078] Fifth blowing stage: Time set to 120s, rotation speed set to 1075-1095r / min;

[0079] The sixth blowing period: the time is set to 180s, and the rotation speed is set to 1070-1090r / min;

[0080] The seventh blowing stage: the time is set to 90 seconds, and the rotation speed is set to 1070-1090 r / min;

[0081] Eighth blowing stage: time set to 120s, speed set to 1080-1100r / min;

[0082] Ninth blowing stage: time set to 900s, speed set to 1090-1110r / min;

[0083] Blowing and feeding period: time set to 60s, rotation speed set to 0+20r / min;

[0084] Measurement period for the blowing lance: time set to 120s, rotation speed set to 0-+20r / min;

[0085] Cup valve switching time: time set to 90s, speed set to +30-+50r / min;

[0086] Before the cup valve is cut off and retracted: the time is set to 30 seconds, and the rotation speed is set to 1060-1080 r / min;

[0087] Period after blowing interruption: time set to 120s, speed set to 1090-1110r / min;

[0088] During periods of excessively high positive pressure: the time is set to 180 seconds, and the rotation speed is set to 1120-1140 r / min.

[0089] The advantages of the above control method and parameter settings are as follows:

[0090] 1) Refined control: Based on the characteristics of different blowing stages (such as feeding, measurement, switching, etc.), different speeds and times are set to ensure that the operation of each stage can accurately match the process requirements and improve smelting efficiency.

[0091] 2) Energy saving and consumption reduction: Reduce the rotation speed during non-high-intensity stages (such as the blowing and feeding period, and the secondary gun measurement period) to reduce energy waste and lower operating costs.

[0092] 3) Good stability: Increase the speed during high load periods (such as periods of slightly high positive pressure) to ensure stable system pressure and avoid production safety issues caused by pressure fluctuations.

[0093] 4) High flexibility: Dynamically adjust speed parameters to cope with sudden situations (such as the period after the blowing is interrupted) or special operations (such as the period of cup valve switching), enhancing the system's ability to cope with complex working conditions.

[0094] 5) Extend equipment life: By rationally distributing the speed load, avoid the fan from operating under overload for a long time, reduce mechanical wear, and extend the service life of the equipment.

[0095] In this embodiment of the invention, in step S2 above, the composition of the molten iron is specifically: Si 0.10%wt%~0.70%wt%, P≤0.14wt%, [C]>4.5wt%.

[0096] In this embodiment of the invention, in step S2 above, the temperature of molten iron is set to 1250~1450℃ (for furnace loading); the total loading amount is set to 168±3t (for furnace loading); the weight of molten iron is set to 130-150t; and the weight of scrap steel is set to 20-35t.

[0097] In this embodiment of the invention, in step S2 above, slag is removed before the molten iron is put into the furnace to ensure that more than 70% of the surface is bright. When adding molten iron, the speed is increased from slow to fast to ensure that the molten iron is spilled. The scrap steel is put into the furnace in a combination of crushed scrap steel, ordinary heavy scrap and shavings briquettes. If the scrap steel is wet, after it is put into the furnace, the converter is tilted at least once at the front and back of the furnace at a angle of 60-70 degrees to prevent explosion.

[0098] In this embodiment of the invention, in step S2 above, when a leak is detected, an emergency response procedure is executed, including immediately raising the lance and starting nitrogen purging, with the nitrogen purging flow rate set to 40,000-45,000 Nm. 3 / h.

[0099] In the embodiments of the present invention, in the above step S3, under different conditions of the silicon content in hot metal, the control parameters of the differential pressure at the furnace mouth are as follows:

[0100] When the silicon content in hot metal is 0.1 < Si ≤ 0.2%, the differential pressure is set to 10 - 30 Pa;

[0101] When the silicon content in hot metal is 0.2 < Si ≤ 0.3%, the differential pressure is set to 20 - 40 Pa;

[0102] When the silicon content in hot metal is 0.3 < Si ≤ 0.4%, the differential pressure is set to 30 - 50 Pa;

[0103] When the silicon content in hot metal is 0.4 < Si ≤ 0.5%, the differential pressure is set to 40 - 60 Pa;

[0104] When the silicon content in hot metal is 0.5 < Si ≤ 0.6%, the differential pressure is set to 50 - 70 Pa.

[0105] Table 2 Control of Different Silicon Contents and Differential Pressure at the Middle-stage Furnace Mouth

[0106] % silicon content in molten iron 0.1 < Si ≤ 0.2 0.2 < Si ≤ 0.3 0.3 < Si ≤ 0.4 0.4 < Si ≤ 0.5 0.5 < Si ≤ 0.6 Micro differential pressure (Pa) 10-30 20-40 30-50 40-60 50-70

[0107] The advantages of the setting in the above step S3 are as follows:

[0108] 1) Precise control and stable smelting process;

[0109] The silicon content directly affects the intensity of the smelting reaction and the gas emission. By setting the differential pressure in grades according to the silicon content, the reaction requirements can be precisely matched, avoiding efficiency losses or safety hazards caused by too high or too low pressure; the higher the silicon content, the greater the gas generation in the furnace. The stepped differential pressure setting can dynamically balance the pressure in the furnace, prevent splashing or excessive negative pressure suction of air, and ensure the stability of smelting.

[0110] 2) Reduction of energy consumption and emissions;

[0111] Low-silicon hot metal (0.1 < Si ≤ 0.2%) requires a lower differential pressure (10 - 30 Pa), reducing the blower load and energy consumption; high-silicon hot metal (0.5 < Si ≤ 0.6%) has a violent reaction. Increasing the differential pressure (50 - 70 Pa) can effectively capture dust and reduce the escape of pollutants, meeting the environmental protection requirements.

[0112] 3) Improvement of molten steel quality;

[0113] Through the linkage control of the differential pressure and the silicon content, ensure that the oxidation-reduction reaction in the furnace is in the best state, reduce impurity inclusions, and improve the purity and compositional uniformity of the molten steel.

[0114] 4) Strong adaptability;

[0115] Covering a silicon content range of 0.1% to 0.6%, with clear parameter segmentation, it can quickly respond to fluctuations in raw material composition, meet the smelting requirements of different batches of hot metal, and enhance process flexibility.

[0116] In the embodiment of the present invention, in the above step S4, under different conditions of hot metal silicon content, the oxygen supply flow control parameters are as follows:

[0117] When the hot metal silicon content is 0.1 < Si ≤ 0.2%, the oxygen supply flow is set to 33000 - 35000 Nm 3 / h;

[0118] When the hot metal silicon content is 0.2 < Si ≤ 0.3%, the oxygen supply flow is set to 35000 - 37000 Nm 3 / h;

[0119] When the hot metal silicon content is 0.3 < Si ≤ 0.4%, the oxygen supply flow is set to 37000 - 39000 Nm 3 / h;

[0120] When the hot metal silicon content is 0.4 < Si ≤ 0.5%, the oxygen supply flow is set to 39000 - 41000 Nm 3 / h;

[0121] When the hot metal silicon content is 0.5 < Si ≤ 0.6%, the oxygen supply flow is set to 41000 - 43000 Nm 3 / h.

[0122] Table 3 Oxygen supply flow control in the main blowing stage

[0123]

[0124] The advantages of the setting in the above step S4 are as follows:

[0125] 1) Accurately match the reaction requirements;

[0126] The hot metal silicon content directly affects the oxygen demand of the oxidation reaction. The higher the silicon content (such as 0.5 < Si ≤ 0.6%), the more intense the oxidation reaction, and the oxygen supply flow needs to be correspondingly increased (41000 - 43,000 Nm 3 / h) to ensure sufficient desiliconization; for low-silicon hot metal (0.1 < Si ≤ 0.2%), the oxygen supply flow is reduced (33000 - 35000 Nm 3 / h) to avoid energy waste caused by excessive oxidation.

[0127] 2) Improve the oxygen utilization rate;

[0128] By regulating the oxygen supply flow through silicon content grading, it avoids redundancy or insufficiency caused by "one-size-fits-all" oxygen supply, significantly reduces oxygen consumption, and saves production costs.

[0129] 3) Stabilize the smelting process;

[0130] Dynamically matched oxygen supply flow can balance the reaction rate in the furnace, prevent reaction lag caused by insufficient oxygen supply or splashing caused by excessive oxygen supply, and ensure a stable and controllable smelting process.

[0131] 4) Improve the quality of molten steel;

[0132] Precise oxygen supply ensures that the oxidation reaction of elements such as silicon and carbon is complete and uniform, reduces impurity residue, improves the purity and composition consistency of molten steel, and meets the smelting requirements of high-end steel.

[0133] 5) Wide process adaptability;

[0134] Covering a silicon content range of 0.1% to 0.6%, each 0.1% interval corresponds to a clear oxygen supply flow rate gradient (e.g., an increase of 2000 Nm per stage). 3 It can quickly respond to fluctuations in raw material composition and adapt to diverse production needs.

[0135] In this embodiment of the invention, the auxiliary control in step S5 specifically includes:

[0136] The fume hood is automatically raised and lowered according to the oxygen supply rhythm of the converter.

[0137] The spray gun medium of the evaporative cooler has been replaced with steam instead of nitrogen.

[0138] In the gas recovery process, the recovery is terminated after a preset time delay following the converter shutdown.

[0139] Multiple fan speed control templates are configured according to oxygen supply intensity and production rhythm, and are adapted to the furnace mouth micro differential pressure control.

[0140] In step S5 above, the fume hood is automatically lowered. In particular, back-drying should be avoided during blowing, especially splashing. A small amount of overflow is acceptable.

[0141] Example

[0142] In this embodiment of the invention, the converter is a 150t top-and-bottom blown converter. Taking the smelting of HRB400EAX as an example, the bottom-blowing gas in the converter smelting process is argon, and the specific operation is as follows:

[0143] Step S1: Adjustment and control of the fan speed before smelting;

[0144] Specifically: the blower speed is 420 r / min when waiting for the converter, 820 r / min when charging iron, 1160 r / min when blowing is interrupted, 800 r / min after blowing ends, 750 r / min when tapping steel, 840 r / min when splashing slag to protect the furnace, and 600 r / min when tapping slag. The blower speed is controlled according to the requirements in Table 1 for different blowing periods.

[0145] Table 4 Control of Fan Speed ​​and Time Before Smelting

[0146] Specifically, the terms "furnace 1", "furnace 2", and "furnace 3" refer to the fan speed, all in r / min.

[0147] Step S2, molten iron preparation;

[0148] Iron composition and temperature: Si 0.30%wt%~0.60%wt%, iron temperature 1330~1450℃ (entering the furnace).

[0149] Table 5 Control of Fan Speed ​​and Time Before Smelting

[0150]

[0151]

[0152] Total charge is 168±3t, molten iron weight is 130-150t (into the furnace), and scrap steel weight is 20-35t.

[0153] Table 6 Control of Molten Iron Weight and Scrap Steel Weight

[0154] Furnace weight of molten iron Weight of shredded scrap steel (t) Weight of ordinary heavy waste (t) Weight of wood shavings pressed into blocks (t) Furnace 1 145.68 7.82 5.69 9.05 Furnace 2 143.34 5.64 7.65 11.86 Furnace 3 139.82 10.21 4.37 13.69

[0155] Step S3, the furnace mouth differential pressure is controlled according to the parameters in Table 7; specifically as follows: early stage of blowing: 0-10 Pa; middle stage of blowing: 10-60 Pa; late stage of blowing: -10 to -20 Pa.

[0156] Table 7 Control of Differential Pressure at the Furnace Mouth

[0157] Early stage (pa) Interim (pa) Later stage (pa) 5 25 -11 7 41 -15 8 51 -17

[0158] Step S4, oxygen supply flow control during the main blowing stage;

[0159] Under different molten iron conditions, the oxygen supply flow rate is controlled according to the parameters in Table 8.

[0160] Table 8 Control of Oxygen Supply Flow Rate

[0161]

[0162]

[0163] Step S5, the relevant controls include:

[0164] 1) The converter oxygen step fume hood is automatically lowered.

[0165] 2) The nitrogen in the converter evaporator cooler spray gun is replaced with steam. The nitrogen temperature is low and the steam temperature is high, thereby increasing the calorific value of the gas.

[0166] 3) Optimize the recovery process: after the converter lance is lifted and blowing stops, delay the recovery for 30 seconds, ensuring safety, to recover all qualified converter gas.

[0167] 4) Three fan speed control templates are set according to different oxygen supply intensities and production rhythms, and matched with furnace mouth differential pressure control to improve the quality of converter gas recovery.

[0168] Step S6: Record the CO value of this furnace after the blowing process is completed.

[0169] Table 9 Average CO content

[0170] Furnace Average CO concentration (%) Furnace 1 55.9 Furnace 2 56.2 Furnace 3 56.8

[0171] In step S2 above, after slag removal before molten iron enters the furnace, the bright surface is 80%, 85%, and 90%. When adding molten iron, the speed is increased from slow to fast. The scrap steel entering the furnace adopts a combination of crushed scrap steel, ordinary heavy scrap, and shavings briquettes. After the scrap steel enters the furnace, the converter is tilted 60-70° twice each towards the front and back of the furnace.

[0172] During the production of the above three furnaces, the scrap steel was dry and uncontaminated, no spillage occurred during iron mixing, and no explosions or leaks occurred during the blowing process.

[0173] In step S5 above, after the initial confirmation of successful ignition, the hood automatically lowers. The process is stable for all three furnace cycles without back-drying or splashing. At the same time, the gas is safely recovered after a delay of more than 30 seconds.

[0174] In step S6 above, the CO concentration value is specifically the average value for the entire furnace run, not an instantaneous value.

[0175] The present invention has been described above by way of example. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A method for improving the quality of coal gas recovery through dry dust removal, characterized in that, The steps include the following: S1. Set and dynamically adjust the fan speed parameters for each stage of converter smelting. Control the fan operation according to the set speed and time parameters based on different operation links and blowing periods in the smelting process. S2. Prepare raw materials and adjust parameters, set and control the composition, temperature and charging amount of molten iron entering the furnace, and set and adjust the charging amount and charging method of scrap steel. S3. Based on the silicon content of the molten iron, set and control the furnace mouth differential pressure parameters accordingly; S4. During the main blowing smelting stage, the oxygen supply flow rate parameters are matched, set, and controlled according to the silicon content of the molten iron. S5. Implement auxiliary control parameter settings and measures, including fume hood operation control parameters, evaporative cooling system medium adjustment parameters, gas recovery program optimization parameters, and fan speed control mode configuration parameters; S6. After smelting, record the average CO recovery value in the coal gas.

2. The method according to claim 1, characterized in that, In step S1, the blower speed is set to 400-440 r / min when waiting for the converter, 800-840 r / min when tapping iron, 1140-1180 r / min when blowing is interrupted, 780-820 r / min after blowing is completed, 730-770 r / min when tapping steel, 820-860 r / min when splashing slag to protect the furnace, and 580-620 r / min when tapping slag.

3. The method according to claim 1, characterized in that, In step S1, the multiple blowing periods include the first to ninth blowing periods, the blowing feeding period, the blowing auxiliary lance measurement period, the cup valve switching period, the period before cup valve retraction, the period after blowing interruption, and the period of slightly high positive pressure. The fan speed and time control for each period are as follows: First blowing period: time set to 60s, speed set to 850-870r / min; Second blowing period: time set to 120s, speed set to 820-840r / min; Third blowing period: time set to 90s, speed set to 840-860r / min; Fourth blowing stage: time set to 30s, speed set to 1065-1085r / min; Fifth blowing stage: Time set to 120s, rotation speed set to 1075-1095r / min; The sixth blowing period: the time is set to 180s, and the rotation speed is set to 1070-1090r / min; The seventh blowing stage: the time is set to 90 seconds, and the rotation speed is set to 1070-1090 r / min; Eighth blowing stage: time set to 120s, speed set to 1080-1100r / min; Ninth blowing stage: time set to 900s, speed set to 1090-1110r / min; Blowing and feeding period: time set to 60s, rotation speed set to 0+20r / min; Measurement period for the blowing lance: time set to 120s, rotation speed set to 0-+20r / min; Cup valve switching time: time set to 90s, speed set to +30-+50r / min; Before the cup valve is cut off and retracted: the time is set to 30 seconds, and the rotation speed is set to 1060-1080 r / min; Period after blowing interruption: time set to 120s, speed set to 1090-1110r / min; During periods of excessively high positive pressure: the time is set to 180 seconds, and the rotation speed is set to 1120-1140 r / min.

4. The method according to any one of claims 1 to 3, characterized in that, In step S2, the molten iron composition is specifically: Si 0.10%wt%~0.70%wt%, P≤0.14wt%, [C]>4.5wt%.

5. The method according to claim 4, characterized in that, In step S2, the molten iron temperature is set to 1250-1450℃; the total loading amount is set to 168±3t; the molten iron weight is set to 130-150t; and the scrap steel weight is set to 20-35t.

6. The method according to any one of claims 1 to 5, characterized in that, In step S3, the furnace mouth differential pressure control parameters are as follows under different silicon content conditions in the molten iron: When the silicon content of molten iron is 0.1% < Si ≤ 0.2%, the differential pressure is set to 10-30 Pa. When the silicon content of molten iron is 0.2% < Si ≤ 0.3%, the differential pressure is set to 20-40 Pa. When the silicon content of molten iron is 0.3% < Si ≤ 0.4%, the differential pressure is set to 30-50 Pa. When the silicon content of molten iron is 0.4% < Si ≤ 0.5%, the differential pressure is set to 40-60 Pa. When the silicon content of molten iron is 0.5% < Si ≤ 0.6%, the differential pressure is set to 50-70 Pa.

7. The method according to any one of claims 1 to 5, characterized in that, In step S4, the oxygen supply flow control parameters are as follows under different iron silicon content conditions: When the silicon content of molten iron is 0.1% < Si ≤ 0.2%, the oxygen supply flow rate should be set to 33,000-35,000 Nm³. 3 / h; When the silicon content of molten iron is 0.2% < Si ≤ 0.3%, the oxygen supply flow rate should be set to 35,000-37,000 Nm³. 3 / h; When the silicon content of molten iron is 0.3% < Si ≤ 0.4%, the oxygen supply flow rate should be set to 37,000-39,000 Nm³. 3 / h; When the silicon content of molten iron is 0.4% < Si ≤ 0.5%, the oxygen supply flow rate should be set to 39000-41000 Nm. 3 / h; When the silicon content of molten iron is 0.5% < Si ≤ 0.6%, the oxygen supply flow rate should be set to 41000-43000 Nm. 3 / h.

8. The method according to any one of claims 1 to 5, characterized in that, In step S5, the implementation of auxiliary control specifically includes: The fume hood is automatically raised and lowered according to the oxygen supply rhythm of the converter. The spray gun medium of the evaporative cooler has been replaced with steam instead of nitrogen. In the gas recovery process, the recovery is terminated after a preset time delay following the converter shutdown. Multiple fan speed control templates are configured according to oxygen supply intensity and production rhythm, and are adapted to the furnace mouth micro differential pressure control.

9. The method according to any one of claims 1 to 5, characterized in that, In step S2, when a leak is detected, an emergency response procedure is executed, including immediately raising the lance and initiating nitrogen purging, with the nitrogen purging flow rate set to 40,000-45,000 Nm. 3 / h.

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