Variable frequency adjusting method and system for steelmaking dust removal fan

Abstract

The invention relates to the technical field of steelmaking dust removal fan frequency adjustment, in particular to a steelmaking dust removal fan frequency conversion adjustment method which comprises the steps that target steel grade information and information of the current smelting stage of molten steel are obtained; and obtaining the initial carbon content and the initial nitrogen content of the molten steel. And setting the target carbon content and the target nitrogen content of the molten steel according to the smelting stage information. And according to the initial carbon content and the target carbon content of the molten steel, the oxygen flow required by smelting is obtained. And obtaining the nitrogen flow required by smelting according to the initial nitrogen content and the target nitrogen content of the molten steel. And the argon flow required by smelting is obtained according to the oxygen flow. And according to the oxygen flow, the nitrogen flow and the argon flow, the flue gas flow in the smelting period is obtained. And controlling the frequency of the dust removal fan based on the flue gas flow. The power consumption of the dust removal fan can be reduced, the production cost is reduced, the influence on the environment and the health of workers is reduced, and the problem that the overall efficiency is low due to local optimum of the dust removal fan can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of frequency regulation of steelmaking dust removal fans, and particularly to a frequency conversion regulation method and system for steelmaking dust removal fans. Background Art

[0002] In the iron and steel smelting industry, the efficiency and intelligence level of the dust removal system directly affect the production environment, resource consumption, and cost management of the enterprise.

[0003] In the prior art, the steelmaking dust removal system still operates at a fixed frequency or adopts a control method based on a simple threshold. This method has the following several defects:

[0004] Energy consumption waste (fixed frequency problem): Many traditional dust removal systems still operate at high power during the stage of low flue gas and dust generation. This results in unnecessary energy consumption by the equipment when the flue gas and dust concentrations are low, causing energy waste and increasing production costs.

[0005] Response lag (threshold triggering mechanism): In the control method based on a simple threshold, when the flue gas is large and the dust concentration exceeds the standard, the system will increase the frequency of the frequency converter. However, due to physical reactions and the execution time of the system, dust diffusion often occurs. Simply increasing the frequency may not be able to control the dust concentration in a timely and effective manner, thus affecting the environmental quality and the health of workers.

[0006] Lack of global optimization (single index): The traditional system fails to comprehensively consider various factors in the smelting process, such as the impact of different smelting stages, production processes, and rhythms on dust generation. This single-index control method cannot achieve the overall optimization of the system and often leads to local optimality while the overall efficiency is low. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a frequency conversion regulation method for a steelmaking dust removal fan.

[0008] The frequency conversion regulation method for the steelmaking dust removal fan provided by the present invention adopts the following technical solutions:

[0009] A frequency conversion regulation method for a steelmaking dedusting fan, the method comprising: obtaining target steel grade information and information on the current smelting stage of the molten steel; obtaining the initial carbon content and initial nitrogen content of the molten steel; setting the target carbon content and target nitrogen content of the molten steel according to the smelting stage information; obtaining the oxygen flow rate required for smelting according to the initial carbon content and the target carbon content of the molten steel; obtaining the nitrogen flow rate required for smelting according to the initial nitrogen content and the target nitrogen content of the molten steel; obtaining the argon flow rate required for smelting according to the oxygen flow rate; obtaining the flue gas flow rate during smelting according to the oxygen flow rate, the nitrogen flow rate and the argon flow rate; and controlling the frequency of the dedusting fan based on the flue gas flow rate.

[0010] Optionally, the smelting stage information includes the main blowing period, the refining period and the reduction period.

[0011] Optionally, when the molten steel is in the main blowing period, the frequency of the dedusting fan in the main blowing period is calculated and adjusted through the following steps:

[0012] Calculate the oxygen flow rate required for the molten steel in the main blowing period through the following formula:

[0013]

[0014] In the formula, C 初始 is the initial carbon content of the molten steel; C 目标 is the target carbon content of the molten steel; W is the mass of the molten steel; η 主吹 is the oxygen utilization rate in the main blowing period, which is between 0.8 and 0.85;

[0015] Calculate the nitrogen flow rate required for the molten steel in the main blowing period through the following formula:

[0016]

[0017] In the formula, N 初始 is the initial nitrogen content of the molten steel; N 目标 is the target nitrogen content of the molten steel; W is the mass of the molten steel; is the nitrogen utilization rate in the main blowing period;

[0018] Calculate the argon flow rate required for the molten steel in the main blowing period through the following formula:

[0019]

[0020] In the formula, K Ar is the argon utilization rate, which is between 0.3 and 0.5;

[0021] Calculate the carbon monoxide flow rate in the main blowing period during the smelting process through the following formula:

[0022]

[0023] In the formula, η CO is the carbon monoxide generation rate during the main blowing period, which is between 0.6 and 0.9;

[0024] The dust load during the main blowing period is calculated by the following formula:

[0025] Q 粉尘 = 0.05 × W × splashing rate;

[0026] In the formula, W is the mass of the molten steel; the splashing rate is between 1% and 3%;

[0027] The flue gas flow rate during the main blowing period is calculated by the following formula:

[0028]

[0029] The basic frequency of the dust removal fan is calculated according to the following formula:

[0030]

[0031] The dust correction frequency is calculated according to the following formula:

[0032] Δf 粉尘 = 0.1 × (actual dust concentration - 50);

[0033] The negative pressure correction frequency is calculated according to the following formula:

[0034] Δf 负压 = 2 × (P 目标 - P 实际 );

[0035] In the formula, P 目标 is the target negative pressure of the dust removal fan; P 实际 is the actual negative pressure of the dust removal fan;

[0036] Finally, the frequency of the dust removal fan during the main blowing period is calculated according to the following formula, and the frequency of the dust removal fan is adjusted to the frequency of the dust removal fan during the main blowing period:

[0037] f 风机 = f 基 + Δf 烟气 + Δf 粉尘 + Δf 负压 .

[0038] Optionally, the control of the frequency of the dust removal fan based on the flue gas flow rate is manual adjustment, and the manual adjustment is carried out according to the following rules: when the flue gas flow rate is between 2000 m 3 / h to 3500 m 3When the flue gas flow rate is between 3500 m 3 / h and 5000 m 3 / h, the reference frequency of the dust removal fan is between 45 Hz and 50 Hz; the dust correction frequency is between 5 Hz and 10 Hz; when the flue gas flow rate is greater than 5000 m 3 / h, the reference frequency of the dust removal fan is locked at 50 Hz; the dust correction frequency is 15 Hz.

[0039] Optionally, when the molten steel is in the refining period, the frequency of the main blowing period dust removal fan is calculated by the following steps:

[0040] Calculate the oxygen flow rate required for the refining period of the molten steel by the following formula:

[0041]

[0042] In the formula, C 初始 is the initial carbon content of the molten steel; C 目标 is the target carbon content of the molten steel; W is the mass of the molten steel; is the refining efficiency, η o2 = 0.78; K temp = 1 + 0.002×(T - 1650), where T is the temperature of the molten steel;

[0043] Calculate the nitrogen flow rate required for the refining period of the molten steel by the following formula:

[0044]

[0045] Calculate the argon flow rate required for the main blowing period of the molten steel by the following formula:

[0046]

[0047] In the formula, K Ar is the argon utilization rate, K Ar = 5;

[0048] Calculate the carbon monoxide flow rate during the refining period in the smelting process by the following formula:

[0049]

[0050] In the formula, η′ CO is the carbon monoxide generation rate during the refining period, η′ CO = 0.4;

[0051] Calculate the dust load during the refining period by the following formula:

[0052] Q′ 粉尘= 0.02 × W × Splashing rate;

[0053] Wherein, W is the mass of the molten steel; the splashing rate ranges from 0.5% to 1.5%;

[0054] The flue gas flow rate during the refining period is calculated by the following formula:

[0055]

[0056] The basic frequency of the dust removal fan is calculated according to the following formula:

[0057]

[0058] The dust correction frequency is calculated according to the following formula:

[0059] Δf′ 粉尘 = 0.1 × (actual dust concentration - 30);

[0060] The negative pressure correction frequency is calculated according to the following formula:

[0061] Δf′ 负压 = 2 × (P′ 目标 - P′ 实际 );

[0062] Wherein, P′ 目标 is the target negative pressure of the dust removal fan; P′ 实际 is the actual negative pressure of the dust removal fan;

[0063] Finally, the frequency of the dust removal fan during the refining period is calculated according to the following formula, and the frequency of the dust removal fan is adjusted to the frequency of the dust removal fan during the refining period:

[0064] f′ 风机 = f′ 基 + Δf′ 粉尘 + Δf′ 负压 .

[0065] Optionally, during the refining period, the control of the frequency of the dust removal fan based on the flue gas flow rate is manual adjustment, and the manual adjustment is carried out according to the following rules: when the flue gas flow rate is between 500 m 3 / h and 800 m 3 / h, the reference frequency of the dust removal fan is between 20 Hz and 25 Hz; the dust correction frequency depends on the amount of dust in the flue gas, and for every 10 mg / m 3 increase in the dust in the flue gas, the dust correction frequency increases by 0.5 Hz; the negative pressure correction frequency depends on the negative pressure at the dust removal fan, and for every 0.1 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.15 Hz; when the flue gas flow rate is between 800 m 3 / h and 1200 m 3When it is between [specific value] h, the reference frequency of the dust removal fan is between 25 Hz and 35 Hz; the dust correction frequency is determined according to the dust amount in the flue gas. For every 10 mg / m increase in the dust in the flue gas, the dust correction frequency increases by 1 Hz; the negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.2 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.2 Hz; when the flue gas flow rate is between 1200 m / h and 2000 m / h, the reference frequency of the dust removal fan is between 35 Hz and 45 Hz; the dust correction frequency is determined according to the dust amount in the flue gas. For every 10 mg / m increase in the dust in the flue gas, the dust correction frequency increases by 2 Hz; the negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.3 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.3 Hz. 3 When the molten steel is in the reduction period, the frequency of the dust removal fan in the reduction period is calculated by the following steps: 3 / h~2000 m / h, the reference frequency of the dust removal fan is between 35 Hz and 45 Hz; the dust correction frequency is determined according to the dust amount in the flue gas. For every 10 mg / m increase in the dust in the flue gas, the dust correction frequency increases by 2 Hz; the negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.3 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.3 Hz. 3 When it is between [specific value] h, the reference frequency of the dust removal fan is between 35 Hz and 45 Hz; the dust correction frequency is determined according to the dust amount in the flue gas. For every 10 mg / m increase in the dust in the flue gas, the dust correction frequency increases by 2 Hz; the negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.3 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.3 Hz. 3 , the dust correction frequency increases by 2 Hz; the negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.3 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.3 Hz.

[0066] Optionally, when the molten steel is in the reduction period, the frequency of the dust removal fan in the reduction period is calculated by the following steps:

[0067] Calculate the reference flow rate of argon required for the molten steel by the following formula:

[0068] Q Ar基 = K Ar ×W;

[0069] In the formula, K Ar is the argon utilization rate, and K Ar is between 1.0 - 1.2; W is the mass of the molten steel;

[0070] Calculate the nitrogen flow rate required for the refining period of the molten steel by the following formula:

[0071]

[0072] In the formula, N 目标 is the target nitrogen content of the molten steel; N 当前 is the current nitrogen content of the molten steel; W is the mass of the molten steel; is the nitrogen utilization rate in the reduction period,

[0073] Calculate the trace oxygen supplement amount required for the molten steel by the following formula:

[0074]

[0075] Calculate the dust load in the refining period by the following formula:

[0076] Q″ 粉尘 = 0.01×W×spatter rate;

[0077] Wherein, W is the mass of the molten steel; the splashing rate ranges from 0.5% to 1.0%;

[0078] The hydrogen flow rate during the refining period is calculated by the following formula:

[0079]

[0080] Wherein, W FeSi is the dosage of FeSi during the reduction period;

[0081] The flue gas flow rate during the refining period is calculated by the following formula:

[0082]

[0083] The base frequency of the dust removal fan is calculated according to the following formula:

[0084]

[0085] The dust correction frequency is calculated according to the following formula:

[0086] Δf″ 粉尘 = 0.1×(actual dust concentration - 30);

[0087] The negative pressure correction frequency is calculated according to the following formula:

[0088] Δf″ 负压 = 1.5×(P″ 目标 - P″ 实际 );

[0089] Wherein, P″ 目标 is the target negative pressure of the dust removal fan; P″ 实际 is the actual negative pressure of the dust removal fan;

[0090] Finally, the frequency of the dust removal fan is calculated according to the following formula and adjusted to the frequency of the dust removal fan during the main blowing period:

[0091] f″ 风机 = f″ 基 + Δf″ 粉尘 + Δf″ 负压 + Δf″ 安全 .

[0092] Wherein, Δf″ 安全 is the safety correction frequency. When Q″ 烟气 > 1500 Nm 2 / h, Δf″ 安全 = 50 Hz. When Q″ 粉尘 > 50 mg / m 3 , Δf″ 安全 = 10 Hz.

[0093] Optionally, the control of the frequency of the dust removal fan based on the flue gas flow rate is manual adjustment, and the manual adjustment is carried out according to the following rules: When the flue gas flow rate is between 0 m 3 / h and 500 m 3 / h, the reference frequency of the dust removal fan is between 20 Hz and 25 Hz; the dust correction frequency is determined according to the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the dust correction frequency increases by 0.5 Hz; the negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases or decreases by 0.15 Hz; When the flue gas flow rate is between 500 m 3 / h and 1000 m 3 / h, the reference frequency of the dust removal fan is between 25 Hz and 35 Hz; the dust correction frequency is determined according to the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the dust correction frequency increases by 1 Hz; the negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases or decreases by 0.2 Hz; When the flue gas flow rate is between 1000 m 3 / h and 2000 m 3 / h, the reference frequency of the dust removal fan is between 35 Hz and 50 Hz; the dust correction frequency is determined according to the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the dust correction frequency increases by 2 Hz; the negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases or decreases by 0.3 Hz.

[0094] Based on the above concept, the present invention also provides a frequency conversion regulation system for a steelmaking dust removal fan, comprising: a flue gas sensor, a pressure sensor, two temperature sensors, a flow sensor, a PLC controller, an inverter, and a human-machine interaction device; wherein, the flue gas sensor is arranged on the hood of the AOD furnace for detecting the flue gas composition and the amount of smoke in the dust removal pipeline; the pressure sensor is arranged in the dust removal bin of the AOD furnace for detecting the pressure in the dust removal pipeline; the two temperature sensors are respectively arranged on the smoke suction pipeline and the dust removal pipeline of the AOD furnace for detecting the temperature of the flue gas in the smoke suction pipeline and the dust removal pipeline; the flow sensor is arranged on the dust removal pipeline of the AOD furnace for detecting the flow rate of the flue gas in the dust removal pipeline; the flue gas sensor, the pressure sensor, the temperature sensors, and the flow sensor are all communicatively connected to the PLC controller and the human-machine interaction device; the human-machine interaction device is communicatively connected to the PLC controller for inputting the target steel grade, the current smelting stage of the molten steel, the initial carbon content of the molten steel, the target carbon content, the initial nitrogen content, and the target nitrogen content to the PLC controller; the PLC controller is communicatively connected to the inverter for obtaining the automatic target frequency of the dust removal fan according to the flue gas composition, the amount of smoke, the pressure, the flue gas flow rate in the dust removal pipeline, and the temperature at the inlet and outlet of the dust removal pipeline, as well as the target steel grade, the smelting stage, the initial carbon content, the target carbon content, the initial nitrogen content, and the target nitrogen content, and issuing a control command to the inverter according to the automatic target frequency; the inverter is used for responding to the control command and adjusting the frequency of the dust removal fan to the automatic target frequency.

[0095] Optionally, the human-machine interaction device is communicatively connected to the inverter, and is further used for manually controlling the frequency of the dust removal fan; during manual control, the human-machine interaction device issues a control command to the inverter to adjust the frequency of the dust removal fan to the manual target frequency; the manual target frequency is obtained from the manual reference frequency, the manual dust correction frequency, and the manual negative pressure correction frequency: the smelting stage includes the main blowing period, the refining period, and the reduction period; during the main blowing period, when the flue gas flow rate is between 2000m 3 / h and 3500m 3 / h, the manual reference frequency of the dust removal fan is between 30Hz and 45Hz; the manual dust correction frequency is between 0Hz and 5Hz; when the flue gas flow rate is between 3500m 3 / h and 5000m 3 / h, the manual reference frequency of the dust removal fan is between 45Hz and 50Hz; the manual dust correction frequency is between 5Hz and 10Hz; when the flue gas flow rate is greater than 5000m 3When it is [h], the manual reference frequency of the dust removal fan is locked at 50 Hz; the manual dust correction frequency is 15 Hz; during the refining period, when the flue gas flow rate is between 500 m 3 / h and 800 m 3 / h, the manual reference frequency of the dust removal fan is between 20 Hz and 25 Hz; the manual dust correction frequency is determined according to the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the manual dust correction frequency increases by 0.5 Hz; the manual negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.1 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases by 0.15 Hz; when the flue gas flow rate is between 800 m 3 / h and 1200 m 3 / h, the manual reference frequency of the dust removal fan is between 25 Hz and 35 Hz; the manual dust correction frequency is determined according to the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the manual dust correction frequency increases by 1 Hz; the manual negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.2 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases by 0.2 Hz; when the flue gas flow rate is between 1200 m 3 / h and 2000 m 3 / h, the manual reference frequency of the dust removal fan is between 35 Hz and 45 Hz; the manual dust correction frequency is determined according to the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the manual dust correction frequency increases by 2 Hz; the manual negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.3 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases by 0.3 Hz; during the reduction period, when the flue gas flow rate is between 0 m 3 / h and 500 m 3 / h, the manual reference frequency of the dust removal fan is between 20 Hz and 25 Hz; the manual dust correction frequency is determined according to the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the manual dust correction frequency increases by 0.5 Hz; the manual negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases or decreases by 0.15 Hz; when the flue gas flow rate is between 500 m 3 / h and 1000 m 3When it is between [specific value] / h, the manual reference frequency of the dust removal fan is between 25 Hz and 35 Hz; the manual dust correction frequency is determined according to the dust amount in the flue gas. For every 10 mg / m³ increase in the dust in the flue gas, the manual dust correction frequency increases by 1 Hz; the manual negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases or decreases by 0.2 Hz; when the flue gas flow rate is between 1000 m 3 / h and 2000 m 3 / h, the manual reference frequency of the dust removal fan is between 35 Hz and 50 Hz; the manual dust correction frequency is determined according to the dust amount in the flue gas. For every 10 mg / m 3 , the manual dust correction frequency increases by 2 Hz; the manual negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases or decreases by 0.3 Hz.

[0096] As described above, the frequency conversion adjustment method of the steelmaking dust removal fan of the present invention has at least the following beneficial effects:

[0097] 1. The frequency conversion adjustment method of the steelmaking dust removal fan of the present invention performs real-time frequency conversion adjustment on the dust removal fan according to parameters such as oxygen flow rate, nitrogen flow rate, argon flow rate, dust load, and negative pressure of the dust removal fan. This method enables the dust removal fan to operate at a low frequency during the low flue gas and low dust stages in the steelmaking process, reducing the power consumption of the dust removal fan, reducing energy waste, and reducing production costs.

[0098] 2. Adjusting the frequency of the dust removal fan in real time according to parameters such as dust load and negative pressure of the dust removal fan can effectively control the dust concentration before the dust diffusion occurs, thereby reducing the impact on environmental quality and the health of staff.

[0099] 3. The method of the present invention adjusts the frequency of the dust removal fan globally according to parameters such as oxygen flow rate, nitrogen flow rate, argon flow rate, dust load, and negative pressure of the dust removal fan, which can avoid the problem of local optimality and low overall efficiency caused by controlling the dust removal fan through a single index in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1 is a schematic diagram of the frequency conversion adjustment system of the AOD furnace and the steelmaking dust removal fan.

[0101] Figure 2 is a block diagram of the frequency conversion adjustment system of the steelmaking dust removal fan.

[0102] Reference numerals: 1, base; 2, furnace body; 3, furnace frame; 4, smoke hood; 41, extension rod; 5, dust removal bin; 6, variable frequency fan; 7, smoke suction pipe; 8, dust removal pipe; 9, flue gas sensor; 10, temperature sensor. Detailed implementation mode

[0103] The following uses specific specific examples to illustrate the implementation mode of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. It should also be understood that the terms used in the embodiments of the present invention are for the purpose of describing specific specific implementation schemes, rather than for limiting the protection scope of the present invention. The test methods without specific conditions indicated in the following embodiments are usually carried out according to conventional conditions or according to the conditions recommended by each manufacturer.

[0104] It should be noted that the structures, proportions, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limited conditions under which the present invention can be implemented. Therefore, they do not have technical substance significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear narration, rather than for limiting the scope under which the present invention can be implemented. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope under which the present invention can be implemented.

[0105] The present invention first discloses a variable frequency adjustment method for a steelmaking dust removal fan, including: obtaining target steel grade information and the current smelting stage information of the molten steel. Obtaining the initial carbon content and initial nitrogen content of the molten steel. Setting the target carbon content and target nitrogen content of the molten steel according to the smelting stage information. Obtaining the oxygen flow rate required for smelting according to the initial carbon content and target carbon content of the molten steel. Obtaining the nitrogen flow rate required for smelting according to the initial nitrogen content and target nitrogen content of the molten steel. Obtaining the argon flow rate required for smelting according to the oxygen flow rate. Obtaining the flue gas flow rate during smelting according to the oxygen flow rate, nitrogen flow rate, and argon flow rate. Controlling the frequency of the dust removal fan based on the flue gas flow rate.

[0106] Since the target steel grade information is different, the gas ratio strategy during the smelting process is different. Taking conventional stainless steel, nitrogen-containing stainless steel, and high-carbon steel as examples, the gas ratio strategies shown in the following table are adopted respectively. At the beginning of smelting, gas is blown into the molten steel according to the gas ratio strategy, and during the smelting process, the gas ratio can be dynamically adjusted according to the actual situation of the molten steel.

[0107] Target steel grade information <![CDATA[Gas ratio (O2:N2:Ar)]]> Conventional stainless steel 1:0:3～1:0:4 Nitrogen-containing stainless steel 1:1:2～1:2:1 High carbon steel 2:0:1～3:0:1

[0108] The smelting stage information includes the main blowing period, refining period, and reduction period. During the main blowing period, high-pressure oxygen is blown into the high-temperature molten iron to oxidize impurity elements such as carbon, silicon, manganese, and phosphorus in the molten iron. After the impurities are oxidized, part of them generates gases such as carbon dioxide and carbon monoxide, and the other part enters the slag. The role of the refining period is to further adjust the composition of the molten steel and improve its purity. The reduction period is to further desulfurize the molten steel in a reducing atmosphere and adjust the composition.

[0109] It should be noted that according to different smelting processes, the smelting stage information may also include the melting period, oxidation period, etc. In this embodiment, the implementation manner of the present invention is described through the three main stages of the main blowing period, refining period, and reduction period.

[0110] The flue gas in the main blowing period is mainly composed of carbon dioxide, nitrogen, argon, carbon monoxide, and dust. Therefore, when the molten steel is in the main blowing period, the frequency of the dust removal fan in the main blowing period is calculated through the following steps:

[0111] Specifically, the blowing amount of oxygen needs to be determined according to the amount of carbon element to be removed in the molten steel. Therefore, the oxygen flow rate required for the molten steel in the main blowing period is calculated by the following formula:

[0112]

[0113] In the formula, C 初始 is the initial carbon content of the molten steel; C 目标 is the target carbon content of the molten steel; W is the mass of the molten steel; η 主吹 is the oxygen utilization rate in the main blowing period, which is between 0.8 and 0.85;

[0114] Nitrogen alloying needs to be achieved during the main blowing period, that is, nitrogen is introduced into the molten steel to introduce nitrogen elements into the metal to improve the mechanical properties and corrosion resistance of the material. The nitrogen flow rate required for the molten steel in the main blowing period is calculated by the following formula:

[0115]

[0116] In the formula, N 初始 is the initial nitrogen content of the molten steel; N 目标 is the target nitrogen content of the molten steel; W is the mass of the molten steel; is the nitrogen utilization rate in the main blowing period;

[0117] During the main blowing period, the function of injecting argon into the molten steel is mainly to inhibit the oxidation of chromium element. The argon flow rate required for the molten steel during the main blowing period is calculated by the following formula:

[0118]

[0119] In the formula, K Ar is the argon utilization rate, which is between 0.3 and 0.5;

[0120] The carbon monoxide flow rate during the main blowing period in the smelting process is calculated by the following formula:

[0121]

[0122] In the formula, η CO is the carbon monoxide generation rate during the main blowing period, which is between 0.6 and 0.9;

[0123] The dust load during the main blowing period is calculated by the following formula:

[0124] Q 粉尘 = 0.05 × W × splashing rate;

[0125] In the formula, W is the mass of the molten steel; the splashing rate is between 1% and 3%;

[0126] The flue gas flow rate during the main blowing period is calculated by the following formula:

[0127]

[0128] The basic frequency of the dust removal fan is calculated according to the following formula:

[0129]

[0130] The dust correction frequency is calculated according to the following formula:

[0131] Δf 粉尘 = 0.1 × (actual dust concentration - 50);

[0132] The negative pressure correction frequency is calculated according to the following formula. The negative pressure is the pressure difference between the inside and the outside of the dust removal pipeline:

[0133] Δf 负压 = 2 × (P 目标 - P 实际 );

[0134] In the formula, P 目标 is the target negative pressure of the dust removal fan; P 实际 is the actual negative pressure of the dust removal fan;

[0135] Finally, the frequency of the dust removal fan during the main blowing period is calculated according to the following formula, and the frequency of the dust removal fan is adjusted to the frequency of the dust removal fan during the main blowing period:

[0136] f 风机 = f 基 + Δf 粉尘 + Δf 负压 。

[0137] Taking the molten steel weight of 75 tons, nitrogen flow rate of 1200 Nm 3 / h, nitrogen flow rate of 300 Nm 3 / h, and argon flow rate of 600 Nm 3 / h as an example,

[0138] Q 烟气 = 1.25×(1200 + 300 + 600) + 0.75 + 1200×0.8 + 75×0.02 = 3346.5 Nm / h.

[0139]

[0140] If the actually measured dust load is 65 mg / m 2 , the target negative pressure of the dust removal fan is -50 Pa, and the actual negative pressure is -40 Pa, then f 风机 = 38.53 + 0.1×(65 - 50) + 2×[-50 - (-40)] ≈ 20 Hz.

[0141] The above process aims to automatically adjust the frequency of the dust removal fan according to the flow rates of oxygen, nitrogen, and argon, as well as the dust load and negative pressure of the dust removal fan during the main blowing period. In actual operation, the control of the frequency of the dust removal fan based on the flue gas flow rate is manual adjustment, and the manual adjustment is carried out according to the following rules: When the flue gas flow rate is between 2000 Nm 3 / h and 3500 Nm 3 / h, the reference frequency of the dust removal fan is between 30 Hz and 45 Hz. The dust correction frequency is between 0 Hz and 5 Hz. When the flue gas flow rate is between 3500 Nm 3 / h and 5000 Nm 3 / h, the reference frequency of the dust removal fan is between 45 Hz and 50 Hz. The dust correction frequency is between 5 Hz and 10 Hz. When the flue gas flow rate is greater than 5000 Nm 3 / h, the reference frequency of the dust removal fan is locked at 50 Hz. The dust correction frequency is 15 Hz.

[0142] The molten steel reduces the carbon content to a relatively low level during the main blowing period. In the refining period, it is necessary to carry out deep decarburization of the molten steel and accurately control the carbon content in the molten steel within the target range value. Therefore, a gas ratio strategy different from that in the main blowing period needs to be adopted. Taking conventional stainless steel, nitrogen-containing stainless steel, and high-carbon steel as examples, the gas ratio strategy at the beginning of the refining period is as follows:

[0143]

[0144]

[0145] After reasonably selecting the gas ratio strategy, calculate the frequency of the dust removal fan during the main blowing period through the following steps:

[0146] Calculate the oxygen flow rate required for the refining period of the molten steel through the following formula:

[0147]

[0148] In the formula, C 初始 is the initial carbon content of the molten steel. C 目标 is the target carbon content of the molten steel. W is the mass of the molten steel. is the refining efficiency, K temp = 1 + 0.002×(T - 1650), where T is the temperature of the molten steel.

[0149] It should be noted here that the molten steel can only enter the refining period after the main blowing period is completed. Therefore, the initial carbon content of the molten steel in the refining period is the carbon content of the molten steel after the main blowing period is completed.

[0150] Calculate the nitrogen flow rate required for the refining period of the molten steel through the following formula:

[0151]

[0152] Calculate the argon flow rate required for the main blowing period of the molten steel through the following formula:

[0153]

[0154] In the formula, K Ar is the argon utilization rate, K Ar = 5.

[0155] Calculate the carbon monoxide flow rate during the refining period in the smelting process through the following formula:

[0156]

[0157] In the formula, η′ CO is the carbon monoxide generation rate during the refining period, η′ CO = 0.4.

[0158] Calculate the dust load during the refining period through the following formula:

[0159] Q′ 粉尘 = 0.02×W×spatter rate.

[0160] In the formula, W is the mass of the molten steel. The spatter rate ranges from 0.5% to 1.5%.

[0161] Calculate the flue gas flow rate during the refining period by the following formula:

[0162]

[0163] Calculate the base frequency of the dust removal fan according to the following formula:

[0164]

[0165] Calculate the dust correction frequency according to the following formula:

[0166] Δf′ 粉尘 = 0.1×(actual dust concentration - 30).

[0167] Calculate the negative pressure correction frequency according to the following formula:

[0168] Δf′ 负压 = 2×(P′ 目标 - P′ 实际 ).

[0169] In the formula, P′ 目标 is the target negative pressure of the dust removal fan. P′ 实际 is the actual negative pressure of the dust removal fan.

[0170] Finally, calculate the frequency of the dust removal fan during the refining period according to the following formula, and adjust the frequency of the dust removal fan to the frequency of the dust removal fan during the refining period:

[0171] f′ 风机 = f′ 基 + Δf′ 粉尘 + Δf′ 负压 .

[0172] Taking the smelting of 75 tons of 304 stainless steel during the refining period as an example, if C 初始 = 0.1%, C 目标 = 0.03%, and the molten steel temperature T = 1670 °C, substituting into the calculation gives:

[0173]

[0174] If the target negative pressure of the dust removal fan is -50 Pa and the actual negative pressure is -45 Pa, then Δf′ 负压 = -7.5 Hz. Finally, the calculated f′ 风机 = 20.5 Hz.

[0175] If the dust removal fan operates at a fixed frequency of 40 Hz during the refining period, it consumes 7.2 kWh of electric energy to smelt each ton of molten steel. However, if the frequency conversion operation of the dust removal fan is adopted using the aforementioned method, it consumes approximately 4.5 kWh of electric energy to smelt each ton of molten steel, and the energy consumption is reduced by 37.5%.

[0176] The above process aims to automatically adjust the frequency of the dust removal fan according to the flow rates of oxygen, nitrogen, and argon, as well as the dust load and negative pressure of the dust removal fan during the refining period. In actual operation, the control of the frequency of the dust removal fan based on the flue gas flow rate is manual adjustment, and the manual adjustment is carried out according to the following rules: When the flue gas flow rate is between 500 Nm 3 / h and 800 Nm 3 / h, the reference frequency of the dust removal fan is between 20 Hz and 25 Hz. The dust correction frequency is determined according to the dust amount in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the dust correction frequency increases by 0.5 Hz. The negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.1 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.15 Hz. When the flue gas flow rate is between 800 Nm 3 / h and 1200 Nm 3 / h, the reference frequency of the dust removal fan is between 25 Hz and 35 Hz. The dust correction frequency is determined according to the dust amount in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the dust correction frequency increases by 1 Hz. The negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.2 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.2 Hz. When the flue gas flow rate is between 1200 Nm 3 / h and 2000 Nm 3 / h, the reference frequency of the dust removal fan is between 35 Hz and 45 Hz. The dust correction frequency is determined according to the dust amount in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the dust correction frequency increases by 2 Hz. The negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.3 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.3 Hz.

[0177] After the molten steel goes through the main blowing period and the refining period, it finally goes through the reduction period to protect the alloy in the molten steel and adjust the slag. At the beginning of the refining period, different gas ratio strategies are adopted according to different target steel grade information:

[0178] Target steel grade information <![CDATA[Gas ratio (O2:N2:Ar)]]> <![CDATA[Cr2O3 in the reducing slag > 10%]]> 1:0:8 Nitrogen-containing steel grade 0:1:5 Non-nitrogen-containing steel grade 0:0:6(0:1:5)

[0179] After selecting the appropriate gas ratio strategy, calculate the frequency of the dust removal fan in the reduction period through the following steps:

[0180] Calculate the reference flow rate of argon required for the molten steel through the following formula. The reference flow rate of argon is the guiding value of the argon flow rate, which reflects the ideal demand for argon in the reduction period:

[0181] Q Ar基 =K Ar ×W.

[0182] Wherein, K Ar is the argon utilization rate, and K Ar is between 1.0 and 1.2. W is the mass of the molten steel.

[0183] The actual flow rate of argon during the reduction period starts from the reference flow rate of argon and is precisely controlled by implementing corrections, ultimately ensuring an optimal balance among process efficiency, safety, and cost.

[0184] The nitrogen flow rate required for the molten steel during the refining period is calculated by the following formula:

[0185]

[0186] Wherein, N 目标 is the target nitrogen content of the molten steel. N 当前 is the current nitrogen content of the molten steel. W is the mass of the molten steel. is the nitrogen utilization rate during the reduction period,

[0187] The micro oxygen supplement amount required for the molten steel is calculated by the following formula:

[0188]

[0189] The dust load during the refining period is calculated by the following formula:

[0190] Q″ 粉尘 = 0.01 × W × spatter rate.

[0191] Wherein, W is the mass of the molten steel. The spatter rate is between 0.5% and 1.0%.

[0192] The hydrogen flow rate during the refining period is calculated by the following formula:

[0193]

[0194] Wherein, W FeSi is the consumption of FeSi during the reduction period.

[0195] The flue gas flow rate during the refining period is calculated by the following formula:

[0196]

[0197] The basic frequency of the dust removal fan is calculated according to the following formula:

[0198]

[0199] The dust correction frequency is calculated according to the following formula:

[0200] Δf″ 粉尘 = 0.1 × (actual dust concentration - 30).

[0201] Calculate the negative pressure correction frequency according to the following formula:

[0202] Δf″ 负压 = 1.5×(P″ 目标 - P″ 实际 >.

[0203] In the formula, P″ 目标 is the target negative pressure of the dust removal fan. P″ 实际 is the actual negative pressure of the dust removal fan.

[0204] Finally, calculate according to the following formula and adjust the frequency of the dust removal fan to the frequency of the dust removal fan during the main blowing period:

[0205] f″ 风机 = f″ 基 + Δf″ 粉尘 + Δf″ 负压 + Δf″ 安全 .

[0206] In the formula, Δf″ 安全 is the safety correction frequency. When Q″ 烟气 > 1500 Nm 3 / h, Δf″ 安全 = 50 Hz. When Q″ 粉尘 > 50 mg / m 3 , Δf″ 安全 = 10 Hz.

[0207] If the gas ratio strategy is O2:N2:Ar = 1:0:8 and the argon flow rate is 82.5 Nm 3 / h, then furthermore, Q″ 烟气 ≈ 811.75 Nm 3 / h can be calculated, and the corresponding f″ 基 = 29 Hz. If the actual dust concentration is 25 mg / m 3 , the target negative pressure is -50 Pa, and the actual negative pressure is -45 Pa, then f" 风机 = 20 Hz.

[0208] The control of the frequency of the dust removal fan based on the flue gas flow rate is manual adjustment, and the manual adjustment is carried out according to the following rules: When the flue gas flow rate is between 0 Nm 3 / h and 500 Nm 3 / h, the reference frequency of the dust removal fan is between 20 Hz and 25 Hz. The dust correction frequency depends on the amount of dust in the flue gas. For every 10 mg / m increase in the dust in the flue gas 3, the dust correction frequency increases by 0.5 Hz. The negative pressure correction frequency depends on the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases or decreases by 0.15 Hz. When the flue gas flow rate is between 500 Nm 3 / h and 1000 Nm 3 / h, the reference frequency of the dust removal fan is between 25 Hz and 35 Hz. The dust correction frequency depends on the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the dust correction frequency increases by 1 Hz. The negative pressure correction frequency depends on the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases or decreases by 0.2 Hz. When the flue gas flow rate is between 1000 Nm 3 / h and 2000 Nm 3 / h, the reference frequency of the dust removal fan is between 35 Hz and 50 Hz. The dust correction frequency depends on the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the dust correction frequency increases by 2 Hz. The negative pressure correction frequency depends on the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases or decreases by 0.3 Hz.

[0209] Compared with the prior art, the frequency conversion regulation method of the steelmaking dust removal fan of the present invention performs real-time frequency conversion regulation on the dust removal fan according to parameters such as oxygen flow rate, nitrogen flow rate, argon flow rate, dust load, and negative pressure of the dust removal fan. This method enables the dust removal fan to operate at a low frequency during the low flue gas and low dust stages in the steelmaking process, reducing the power consumption of the dust removal fan, reducing energy waste, and lowering production costs.

[0210] Secondly, adjusting the frequency of the dust removal fan in real time according to parameters such as dust load and negative pressure of the dust removal fan can effectively control the dust concentration before the dust diffusion occurs, thereby reducing the impact on environmental quality and the health of staff.

[0211] In addition, the method of the present invention adjusts the frequency of the dust removal fan globally according to parameters such as oxygen flow rate, nitrogen flow rate, argon flow rate, dust load, and negative pressure of the dust removal fan, which can avoid the problem of local optimality and low overall efficiency caused by controlling the dust removal fan through a single index in the prior art.

[0212] The present invention also discloses a frequency conversion regulation system for a steelmaking dust removal fan, which is applied to the frequency conversion regulation of the dust removal fan of an AOD furnace.

[0213] Please refer to Figure 1 and Figure 2, An AOD (Argon-Oxygen Decarburization) furnace, that is, an argon-oxygen decarburization furnace, can remove carbon in the steel grade through argon and oxygen. The AOD furnace includes a base 1, a furnace body 2, a furnace frame 3, a hood 4, a dust removal bin 5, and a variable frequency fan 6. The furnace body 2 is erected on the base 1 through the furnace frame 3. The inlet of the hood 4 is arranged directly above the furnace body 2 for extracting the flue gas in the furnace body 2. The outlet of the hood 4 is connected to the inlet of the dust removal bin 5 through a smoke suction pipe 7. The outlet of the dust removal bin 5 is connected to the variable frequency fan 6 through a dust removal pipe 8. Driven by the variable frequency fan 6, the flue gas in the furnace body 2 is discharged after passing through the hood 4, the smoke suction pipe 7, the dust removal bin 5, the dust removal pipe 8, and the variable frequency fan 6.

[0214] The variable frequency regulation system of the steelmaking dust removal fan of the present invention includes a flue gas sensor 9, a pressure sensor, a temperature sensor 10, a flow sensor, a PLC controller, an inverter, and a human-machine interaction device.

[0215] Among them, the flue gas sensor 9 is arranged on the hood 4 of the AOD furnace for detecting the flue gas composition and smoke volume in the dust removal pipe 8. The pressure sensor is arranged in the dust removal bin 5 of the AOD furnace for detecting the pressure in the dust removal pipe 8. Two temperature sensors 10 are respectively arranged on the smoke suction pipe 7 and the dust removal pipe 8 of the AOD furnace for the temperature of the flue gas in the smoke suction pipe 7 and the dust removal pipe 8. The flow sensor is arranged on the dust removal pipe 8 of the AOD furnace for detecting the flow rate of the flue gas in the dust removal pipe 8. The flue gas sensor 9, the pressure sensor, the temperature sensor 10, and the flow sensor are all communicatively connected to the PLC controller and the human-machine interaction device. The human-machine interaction device is communicatively connected to the PLC controller for inputting the target steel grade, the current smelting stage of the molten steel, the initial carbon content of the molten steel, the target carbon content, the initial nitrogen content, and the target nitrogen content into the PLC controller. The PLC controller is communicatively connected to the inverter for obtaining the automatic target frequency of the dust removal fan according to the flue gas composition, smoke volume, pressure, flue gas flow rate in the dust removal pipe 8, and the temperature at the inlet and outlet of the dust removal pipe 8, as well as the target steel grade, smelting stage, initial carbon content, target carbon content, initial nitrogen content, and target nitrogen content, and sending a control command to the inverter according to the automatic target frequency. The inverter is used to respond to the control command and adjust the frequency of the dust removal fan to the automatic target frequency.

[0216] In a preferred embodiment of the present invention, a prolonging rod 41 is arranged on the outer wall of the hood 4. The prolonging rod 41 is horizontally arranged. The flue gas sensor 9 is arranged at the end of the prolonging rod 41 away from the hood 4 and points downward to the upper side of the furnace body 2. Compared with arranging the flue gas sensor 9 in the hood 4, the influence of the flue gas sensor 9 on the flue gas flow can be reduced.

[0217] The frequency conversion regulation system of the steelmaking dust removal fan of the present invention can adjust the frequency of the dust removal fan through the above-mentioned frequency conversion regulation method of the steelmaking dust removal fan: input the target steel grade information and smelting stage information into the PLC control through the human-machine interaction device. The PLC uses the parameters measured by the pressure sensor, temperature sensor 10, and flow sensor, and obtains the automatic target frequency of the dust removal fan by using the above-mentioned frequency conversion regulation method of the steelmaking dust removal fan, and then generates a control instruction. Through the frequency converter, the frequency of the dust removal fan can be adjusted to the automatic target frequency. In a preferred embodiment of the present invention, the human-machine interaction device is communicatively connected to the frequency converter, and is also used to manually control the frequency of the dust removal fan; during manual control, the human-machine interaction device sends a control instruction to the frequency converter to adjust the frequency of the dust removal fan to the manual target frequency; the manual target frequency is obtained from the manual reference frequency, manual dust correction frequency, and manual negative pressure correction frequency.

[0218] The smelting stage includes the main blowing period, refining period, and reduction period;

[0219] During the main blowing period, when the flue gas flow rate is between 2000 Nm 3 / h and 3500 Nm 3 / h, the manual reference frequency of the dust removal fan is between 30 Hz and 45 Hz; the manual dust correction frequency is between 0 Hz and 5 Hz; when the flue gas flow rate is between 3500 Nm 3 / h and 5000 Nm 3 / h, the manual reference frequency of the dust removal fan is between 45 Hz and 50 Hz; the manual dust correction frequency is between 5 Hz and 10 Hz; when the flue gas flow rate is greater than 5000 Nm 3 / h, the manual reference frequency of the dust removal fan is locked at 50 Hz; the manual dust correction frequency is 15 Hz;

[0220] During the refining period, when the flue gas flow rate is between 500 Nm 3 / h and 800 Nm 3 / h, the manual reference frequency of the dust removal fan is between 20 Hz and 25 Hz; the manual dust correction frequency depends on the dust amount in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the manual dust correction frequency increases by 0.5 Hz; the manual negative pressure correction frequency depends on the negative pressure at the dust removal fan. For every 0.1 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases by 0.15 Hz; when the flue gas flow rate is between 800 Nm 3 / h and 1200 Nm 3 / h, the manual reference frequency of the dust removal fan is between 25 Hz and 35 Hz; the manual dust correction frequency depends on the dust amount in the flue gas. For every 10 mg / m 3, the manual dust correction frequency increases by 1 Hz; the manual negative pressure correction frequency depends on the negative pressure at the dust removal fan. For every 0.2 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases by 0.2 Hz; when the flue gas flow rate is between 1200 Nm 3 / h and 2000 Nm 3 / h, the manual reference frequency of the dust removal fan is between 35 Hz and 45 Hz; the manual dust correction frequency depends on the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the manual dust correction frequency increases by 2 Hz; the manual negative pressure correction frequency depends on the negative pressure at the dust removal fan. For every 0.3 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases by 0.3 Hz;

[0221] During the reduction period, when the flue gas flow rate is between 0 Nm 3 / h and 500 Nm 3 / h, the manual reference frequency of the dust removal fan is between 20 Hz and 25 Hz; the manual dust correction frequency depends on the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the manual dust correction frequency increases by 0.5 Hz; the manual negative pressure correction frequency depends on the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases or decreases by 0.15 Hz; when the flue gas flow rate is between 500 Nm 3 / h and 1000 Nm 3 / h, the manual reference frequency of the dust removal fan is between 25 Hz and 35 Hz; the manual dust correction frequency depends on the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the manual dust correction frequency increases by 1 Hz; the manual negative pressure correction frequency depends on the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases or decreases by 0.2 Hz; when the flue gas flow rate is between 1000 Nm 3 / h and 2000 Nm 3 / h, the manual reference frequency of the dust removal fan is between 35 Hz and 50 Hz; the manual dust correction frequency depends on the dust content in the flue gas. For every 10 mg / m 3 increase in the dust in the flue gas, the manual dust correction frequency increases by 2 Hz; the manual negative pressure correction frequency depends on the negative pressure at the dust removal fan. For every 10 Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases or decreases by 0.3 Hz.

[0222] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A frequency conversion adjustment method for a steelmaking dust removal fan, characterized in that: The method comprises: Obtain information about the target steel grade and the current smelting stage of the molten steel; Obtaining the initial carbon content and initial nitrogen content of the molten steel; and setting the target carbon content and target nitrogen content of the molten steel according to the smelting stage information; According to the initial carbon content and the target carbon content of the molten steel, the oxygen flow rate required for smelting is obtained; according to the initial nitrogen content and the target nitrogen content of the molten steel, the nitrogen flow rate required for smelting is obtained; according to the oxygen flow rate, the argon flow rate required for smelting is obtained; Determining the flue gas flow rate during smelting according to the oxygen flow rate, the nitrogen flow rate and the argon flow rate; The frequency of the dust removal fan is controlled based on the flue gas flow rate.

2. The method according to claim 1, characterized in that: The smelting stage information includes the main blowing period, the refining period and the reduction period.

3. The method according to claim 2, characterized in that: The molten steel is in the main blowing period, and the frequency of the dust removal fan in the main blowing period is calculated and adjusted by the following steps: The oxygen flow rate required for the main blowing period of the molten steel is calculated by the following formula: In the formula, C 初始 is the initial carbon content of the molten steel; C 目标 is the target carbon content of molten steel; W is the mass of molten steel; η 主吹 is the oxygen utilization rate during the main blowing period, which is between 0.8 and 0.85; The nitrogen flow rate required for the main blowing period of molten steel is calculated by the following formula: Where N 初始 is the initial nitrogen content of molten steel; N 目标 is the target nitrogen content of molten steel; W is the mass of molten steel; is the nitrogen utilization rate during the main blowing period; The argon gas flow rate required for the main blowing period of molten steel is calculated by the following formula: In the formula, K Ar is the argon utilization rate, between 0.3 and 0.5; The carbon monoxide flow rate during the main blowing period of the smelting process is calculated by the following formula: Where η CO is the carbon monoxide generation rate during the main blowing period, which is between 0.6 and 0.9; The dust load during the main blowing period is calculated by the following formula: Q 粉尘 =0.05×W×sputtering rate; Where W is the mass of molten steel; the splashing rate is between 1% and 3%; The main blowing period flue gas flow rate is calculated by the following formula: Calculate the basic frequency of the dust removal fan according to the following formula: Calculate the dust correction frequency according to the following formula: Δf 粉尘 =0.1×(actual dust concentration-50); Calculate the negative pressure correction frequency according to the following formula: Δf 负压 =2×(P 目标 -P 实际 ); Where P 目标 is the target negative pressure of the dust removal fan; P 实际 is the actual negative pressure of the dust removal fan; Finally, the frequency of the dust removal fan during the main blowing period is calculated according to the following formula, and the frequency of the dust removal fan is adjusted to the frequency of the dust removal fan during the main blowing period: f 风机 =f 基 +Δf 粉尘 +Δf 负压 。 4. The method according to claim 3, characterized in that During the main blowing period, the frequency of the dust removal fan is controlled manually based on the flue gas flow rate, and the manual adjustment is performed according to the following rules: When the flue gas flow rate is between 2000Nm 3 / h~3500Nm 3 / h, the base frequency of the dust removal fan is between 30Hz and 45Hz; the dust correction frequency is between 0Hz and 5Hz; When the flue gas flow rate is between 3500Nm 3 / h~5000Nm 3 / h, the base frequency of the dust removal fan is between 45Hz and 50Hz; the dust correction frequency is between 5Hz and 10Hz; When the flue gas flow rate is greater than 5000Nm 3 / h, the base frequency of the dust removal fan is locked at 50Hz; the dust correction frequency is 15Hz.

5. The method according to claim 2, characterized in that: The molten steel is in the refining stage, and the frequency of the dust removal fan in the main blowing stage is calculated by the following steps: The oxygen flow rate required for the refining period of the molten steel is calculated by the following formula: In the formula, C 初始 is the initial carbon content of the molten steel; C 目标 is the target carbon content of the molten steel; W is the mass of the molten steel; For refining efficiency, K temp =1+0.002×(T-1650), T is the temperature of molten steel; The nitrogen flow rate required for molten steel during refining is calculated by the following formula: The argon flow rate required for the main blowing period of molten steel is calculated by the following formula: In the formula, K Ar is the utilization rate of argon gas, K Ar =5; The carbon monoxide flow rate during the refining phase of the smelting process is calculated by the following formula: Where η′ CO is the carbon monoxide generation rate during the refining period, η′ CO =0.4; The dust load during the refining period is calculated by the following formula: Q′ 粉尘 =0.02×W×sputtering rate; Where W is the mass of molten steel; the splashing rate is between 0.5% and 1.5%; The flue gas flow rate during the refining period is calculated by the following formula: Calculate the basic frequency of the dust removal fan according to the following formula: Calculate the dust correction frequency according to the following formula: Δf′ 粉尘 =0.1×(actual dust concentration-30); Calculate the negative pressure correction frequency according to the following formula: Δf′ 负压 =2×(P′ 目标 -P′ 实际 ); In the formula, P′ 目标 is the target negative pressure of the dust removal fan; P′ 实际 is the actual negative pressure of the dust removal fan; Finally, the dust removal fan frequency during the refining period is calculated according to the following formula, and the frequency of the dust removal fan is adjusted to the dust removal fan frequency during the refining period: f′ 风机 =f′ 基 +Δf′ 粉尘 +Δf′ 负压 。 6. The method according to claim 5, characterized in that: During the refining period, the frequency of the dust removal fan is controlled manually based on the flue gas flow rate, and the manual adjustment is performed according to the following rules: When the flue gas flow rate is between 500Nm 3 / h~800Nm 3 / h, the base frequency of the dust removal fan is between 20Hz and 25Hz; the dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the dust correction frequency increases by 0.5Hz; the negative pressure correction frequency is determined by the negative pressure at the dust removal fan. For every 0.1Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.15Hz; When the flue gas flow rate is between 800Nm 3 / h~1200Nm 3 / h, the base frequency of the dust removal fan is between 25Hz and 35Hz; the dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the dust correction frequency increases by 1Hz; the negative pressure correction frequency is determined by the negative pressure at the dust removal fan. For every 0.2Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.2Hz; When the flue gas flow rate is between 1200Nm 3 / h~2000Nm 3 / h, the base frequency of the dust removal fan is between 35Hz and 45Hz; the dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the dust correction frequency increases by 2Hz; the negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 0.3Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases by 0.3Hz.

7. The method according to claim 2, characterized in that: The molten steel is in the reduction period, and the frequency of the dust removal fan in the reduction period is calculated by the following steps: The required argon base flow rate of the molten steel is calculated by the following formula: Q Ar基 =K Ar ×W; In the formula, K Ar is the argon utilization rate, K Ar Between 1.0-1.2; W is the mass of molten steel; The nitrogen flow rate required for molten steel during refining is calculated by the following formula: Where N 目标 is the target nitrogen content of molten steel; N 当前 is the current nitrogen content of molten steel; W is the mass of molten steel; is the nitrogen utilization rate in the reduction period, The required amount of oxygen supplement for molten steel is calculated by the following formula: The dust load during the refining period is calculated by the following formula: Q″ 粉尘 =0.01×W×sputtering rate; Where W is the mass of molten steel; The splash rate is between 0.5% and 1.0%; The hydrogen flow rate during the refining period is calculated by the following formula: Where W FeSi is the amount of FeSi used in the reduction period; The flue gas flow rate during the refining period is calculated by the following formula: Calculate the basic frequency of the dust removal fan according to the following formula: Calculate the dust correction frequency according to the following formula: Δf″ 粉尘 =0.1×(actual dust concentration-30); Calculate the negative pressure correction frequency according to the following formula: Δf″ 负压 =1.5×(P″ 目标 -P″ 实际 ); In the formula, P″ 目标 is the target negative pressure of the dust removal fan; P″ 实际 is the actual negative pressure of the dust removal fan; Finally, the frequency of the dust removal fan is calculated and adjusted to the frequency of the dust removal fan during the main blowing period according to the following formula: f″ 风机 =f″ 基 +Δf″ 粉尘 +Δf″ 负压 +Δf″ 安全 。 Where, Δf″ 安全 To correct the frequency for safety, when Q″ 烟气 >1500Nm 3 / h, Δf″ 安全 =50Hz, when Q″ 粉尘 >50 mg / m 3 When Δf″ 安全 =10Hz.

8. The method according to claim 7, characterized in that: During the reduction period, the frequency of the dust removal fan is controlled manually based on the flue gas flow rate, and the manual adjustment is performed according to the following rules: When the flue gas flow rate is between 0Nm 3 / h~500Nm 3 / h, the base frequency of the dust removal fan is between 20Hz and 25Hz; the dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the dust correction frequency increases by 0.5Hz; the negative pressure correction frequency is determined by the negative pressure at the dust removal fan. For every 10Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases or decreases by 0.15Hz; When the flue gas flow rate is between 500Nm 3 / h~1000Nm 3 / h, the base frequency of the dust removal fan is between 25Hz and 35Hz; the dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the dust correction frequency increases by 1Hz; the negative pressure correction frequency is determined by the negative pressure at the dust removal fan. For every 10Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases or decreases by 0.2Hz; When the flue gas flow rate is between 1000Nm 3 / h~2000Nm 3 / h, the base frequency of the dust removal fan is between 35Hz and 50Hz; the dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the dust correction frequency increases by 2Hz; the negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 10Pa decrease in the negative pressure at the dust removal fan, the negative pressure correction frequency increases or decreases by 0.3Hz.

9. A frequency conversion adjustment system for a steelmaking dust removal fan, characterized in that: include: A smoke sensor (9), a pressure sensor, two temperature sensors (10), a flow sensor, a PLC controller, a frequency converter and a human-machine interaction device; wherein: The smoke sensor (9) is arranged on the smoke hood (4) of the AOD furnace and is used to detect the smoke composition and smoke volume in the dust removal pipeline (8); The pressure sensor is arranged in the dust removal bin (5) of the AOD furnace and is used to detect the pressure in the dust removal pipeline (8); The two temperature sensors (10) are respectively arranged on the smoking duct (7) and the dust removal duct (8) of the AOD furnace, and are used to measure the temperature of the flue gas in the smoking duct (7) and the dust removal duct (8); The flow sensor is arranged on the dust removal pipeline (8) of the AOD furnace and is used to detect the flow rate of the flue gas in the dust removal pipeline (8); The smoke sensor (9), the pressure sensor, the temperature sensor (10) and the flow sensor are all connected to the PLC controller and the human-machine interaction device for communication; The human-computer interaction device is in communication connection with the PLC controller, and is used to input the target steel grade, the current smelting stage of the molten steel, the initial carbon content of the molten steel, the target carbon content, the initial nitrogen content, and the target nitrogen content into the PLC controller; The PLC controller is communicatively connected with the frequency converter, and is used to obtain an automatic target frequency of the dust removal fan according to the flue gas composition, the smoke volume, the pressure, the flue gas flow rate, and the temperature at the inlet and outlet of the dust removal pipe (8), the target steel grade, the smelting stage, the initial carbon content, the target carbon content, the initial nitrogen content, and the target nitrogen content in the dust removal pipe (8), and send a control instruction to the frequency converter according to the automatic target frequency; The frequency converter is used to respond to the control instruction and adjust the frequency of the dust removal fan to the automatic target frequency.

10. The variable frequency regulation system for the dust removal fan according to claim 9, characterized in that: The human-machine interaction device is connected to the frequency converter for manual control of the frequency of the dust removal fan. During manual control, the human-machine interaction device sends a control instruction to the frequency converter to adjust the frequency of the dust removal fan to a manual target frequency. The manual target frequency is obtained by the manual reference frequency, the manual dust correction frequency and the manual negative pressure correction frequency: The smelting stage includes a main blowing period, a refining period and a reduction period; During the main blowing period, when the flue gas flow rate is between 2000 Nm 3 / h~3500Nm 3 / h, the manual reference frequency of the dust removal fan is between 30Hz and 45Hz; the manual dust correction frequency is between 0Hz and 5Hz; when the flue gas flow rate is between 3500Nm 3 / h~5000Nm 3 / h, the manual reference frequency of the dust removal fan is between 45Hz and 50Hz; the manual dust correction frequency is between 5Hz and 10Hz; when the flue gas flow rate is greater than 5000Nm 3 / h, the manual reference frequency of the dust removal fan is locked at 50Hz; the manual dust correction frequency is 15Hz; During the refining period, when the flue gas flow rate is between 500 Nm 3 / h~800Nm 3 / h, the manual reference frequency of the dust removal fan is between 20Hz and 25Hz; the manual dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the manual dust correction frequency increases by 0.5Hz; the manual negative pressure correction frequency is determined by the negative pressure at the dust removal fan. For every 0.1Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases by 0.15Hz; when the flue gas flow rate is between 800Nm 3 / h~1200Nm 3 / h, the manual reference frequency of the dust removal fan is between 25Hz and 35Hz; the manual dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the manual dust correction frequency increases by 1Hz; the manual negative pressure correction frequency is determined by the negative pressure at the dust removal fan. For every 0.2Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases by 0.2Hz; when the flue gas flow rate is between 1200Nm 3 / h~2000Nm 3 / h, the manual reference frequency of the dust removal fan is between 35Hz and 45Hz; the manual dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the manual dust correction frequency increases by 2Hz; the manual negative pressure correction frequency is determined by the negative pressure at the dust removal fan. For every 0.3Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases by 0.3Hz; During the reduction period, when the flue gas flow rate is between 0 Nm 3 / h~500Nm 3 / h, the manual reference frequency of the dust removal fan is between 20Hz and 25Hz; the manual dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the manual dust correction frequency increases by 0.5Hz; the manual negative pressure correction frequency is determined by the negative pressure at the dust removal fan. For every 10Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases or decreases by 0.15Hz; when the flue gas flow rate is between 500Nm 3 / h~1000Nm 3 / h, the manual reference frequency of the dust removal fan is between 25Hz and 35Hz; the manual dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the manual dust correction frequency increases by 1Hz; the manual negative pressure correction frequency is determined by the negative pressure at the dust removal fan. For every 10Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases or decreases by 0.2Hz; when the flue gas flow rate is between 1000Nm 3 / h~2000Nm 3 / h, the manual reference frequency of the dust removal fan is between 35Hz and 50Hz; the manual dust correction frequency is determined according to the amount of dust in the flue gas. 3 , the manual dust correction frequency increases by 2Hz; the manual negative pressure correction frequency is determined according to the negative pressure at the dust removal fan. For every 10Pa decrease in the negative pressure at the dust removal fan, the manual negative pressure correction frequency increases or decreases by 0.3Hz.

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