An on-line monitoring method for air leakage rate of an iron ore sintering whole system

Abstract

The application discloses an on-line monitoring method for air leakage rate of an iron ore sintering system, which comprises the following steps: 1) adjusting sintering production parameters so that the sintering production state is stable, and obtaining sintering process working condition parameters in the stable state; 2) calculating working condition flue gas flow of a sintering main exhaust fan; 3) converting the working condition flue gas flow of the sintering main exhaust fan into standard condition flue gas flow; and 4) calculating actual sintering air volume through the sintering main exhaust fan, comparing the actual sintering air volume with theoretical sintering air volume of sintering materials in normal production, and obtaining total air leakage rate of a sintering-dedusting system. The sintering process working condition parameters in the stable production state are obtained in real time by using a sintering central control system, the working condition and standard condition flue gas flow of the sintering main exhaust fan are automatically calculated by deducting water vapor, the total air leakage rate of the sintering system including the sintering and dedusting processes is obtained in real time by comparison with the theoretical sintering air volume of the sintering materials in the normal production, and the purpose of conveniently and quickly monitoring the sintering air leakage rate in real time is achieved.

Description

Technical Field

[0001] This invention relates to a method for monitoring the air leakage rate of a sintering system, specifically to an online monitoring method for the air leakage rate of the entire iron ore sintering system, belonging to the field of iron ore sintering technology. Background Technology

[0002] Sintered ore is a major raw material for blast furnace ironmaking in my country, making iron ore sintering an indispensable part of steel smelting. In actual sinter production, various air leakage phenomena exist during sintering machine operation, such as air leakage from the trolley, air boxes and their branch pipes, double-layer ash discharge valves, flue gas ducts, and electrostatic precipitators. The amount of air leakage directly affects the production technology and economic indicators of sintered ore, and is usually measured by the leakage rate. In actual production, due to the large size and complexity of the sintering system, as well as the differences in the age of the equipment, the system leakage rate varies greatly between different sintering machines, ranging from as low as 20% to as high as 60%. For the same sintering machine, the leakage rate is also not fixed as factors such as its commissioning time, raw material conditions, and operating conditions change. Because of the significant impact of the leakage rate on sintering production, monitoring it is of great importance. Currently, the most widely used method for detecting air leakage rate in sintering machines is the balance calculation method. This method involves sampling flue gas at various measurement points for compositional analysis, while simultaneously measuring the flue gas flow rate at the sampling points. Based on the law of conservation of mass, an equation is established to ensure that the total content of a certain component (O2, CO2) in the flue gas remains balanced before and after the process, indirectly calculating the air leakage rate. However, this method requires numerous flue gas sampling points, is labor-intensive, cannot be continuously measured, has large analytical errors, and the measurement results have limited time-sensitivity, making it difficult to assess air leakage in the sintering system in real time and guide equipment maintenance and sintering production.

[0003] Chinese patent application CN113218599A discloses an online method for detecting air leakage rate in a sintering machine. This method involves installing thermocouples at the inlet of each air box near the grate and at the branch pipes at the outlet of the air box to collect temperature data in real time and calculate the air leakage rate of each air box. Pressure transmitters are installed at each branch pipe to detect the dynamic pressure of the flue gas inside the pipes. Based on the dynamic pressure data of each branch pipe, the air leakage rate of each branch pipe is weighted to calculate the overall system air leakage rate of the sintering machine. Chinese patent application CN114777485A discloses an online intelligent monitoring method for sintering air leakage based on big data. This method collects data on the oxygen content of flue gas inside the sintering machine air box and before and after dust removal by the electrostatic precipitator. Then, it calculates the air leakage rate in a specific range based on an oxygen balance algorithm. Combined with sintering production parameters, a sequence anomaly technology algorithm is used to mine abnormal data and monitor air leakage throughout the entire sintering process.

[0004] Traditional balance calculation methods for obtaining sintering leakage rates involve numerous flue gas sampling points, high labor intensity, and are not suitable for continuous measurement, resulting in large analytical errors. The measurement results also have limited timeliness, making it difficult to assess sintering system leakage in real time and guide equipment maintenance and sintering production. Existing patents have addressed the problems of long detection cycles, high detection costs, and low intelligence levels of traditional sintering leakage detection methods to some extent. However, they still require the installation of temperature, flue gas composition, and other detection equipment at multiple stages to obtain relevant data, resulting in complex processes and a large workload for equipment maintenance and replacement. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes an online monitoring method for the air leakage rate of the entire iron ore sintering system. This method utilizes the sintering central control system to acquire real-time sintering process parameters under stable production conditions. It automatically calculates the operating conditions and standard flue gas flow rate of the main sintering exhaust fan (excluding water vapor), and obtains the air leakage rate of the entire sintering system, including sintering and dust removal processes, in real time by comparing it with the theoretical sintering air volume of the sintered material during normal production. This achieves convenient, fast, and real-time online monitoring of the sintering air leakage rate, overcoming the problems of long detection cycles, high detection costs, low intelligence, complex processes, and large workload for maintenance and replacement of detection equipment in existing sintering air leakage rate detection methods.

[0006] According to an embodiment of the present invention, an online monitoring method for the air leakage rate of the entire iron ore sintering system is provided.

[0007] A method for online monitoring of air leakage rate in an iron ore sintering system, comprising the following steps:

[0008] 1) Adjust the sintering production parameters to stabilize the sintering production state and obtain the sintering process parameters under stable conditions.

[0009] 2) Calculate the operating flue gas flow rate of the sintering main exhaust fan.

[0010] 3) Convert the operating flue gas flow rate of the sintering main exhaust fan to the standard flue gas flow rate.

[0011] 4) Calculate the actual sintering air volume through the main sintering exhaust fan and compare it with the theoretical sintering air volume of the sintering material during normal production to obtain the total air leakage rate of the sintering-dust removal system.

[0012] In this invention, the method further includes:

[0013] 5) Obtain the oxygen content in the flue gas at the inlet and outlet of the sintering dust collector, and calculate the air leakage rate of the dust removal system based on the oxygen balance algorithm.

[0014] In this invention, the method further includes:

[0015] 6) Calculate the air leakage rate of the sintering system to achieve online monitoring of the air leakage rate of the entire iron ore sintering system.

[0016] In the present invention, in step 1), the acquisition of the sintering process condition parameters under the stable state specifically includes the following sub-steps:

[0017] ① Calculate the sintering material consumption: Automatically collect the charging amount m1 of the sintering raw materials, the return ore blending amount m2, the bedding charging amount m3, and the sintering water addition amount m4 by the sintering central control system, and calculate the sintering material consumption M. That is:

[0018] M = m1 + m2 + m3 + m4…(Equation 1).

[0019] ② Calculate the power P of the main sintering exhaust fan

[0025] ,

[0020] , tb ,

[0023] , p , e2 ,

[0024] , t , ta ,

[0021] , 工 , e1 ,

[0026] ,

[0022] , in , , e2 , , tb , e1 , , ta , , t , t , , 工 , , out , :

[0020] [[ID=十七]]When the main sintering exhaust fan is a constant frequency fan, automatically collect the input voltage U, current I, power factor cosΦ, efficiency η1 of the motor supporting the constant frequency main sintering exhaust fan, and motor transmission efficiency T by the sintering central control system e1 , and calculate the shaft power P of the constant frequency main sintering exhaust fan ta . That is:

[0021] P ta = U × I × √3 × cosΦ × η1 × T e1 …(Equation 2).

[0022] When the main sintering exhaust fan is a variable frequency fan, automatically collect the real-time output power P of the frequency converter supporting the variable frequency main sintering exhaust fan, the efficiency η2 of the supporting motor, and the motor transmission efficiency T e2 , and calculate the shaft power P of the variable frequency main sintering exhaust fan tb . That is:

[0023] P tb = P × η2 × T e2 …(Equation 3).

[0024] ③ Automatically collect the inlet pressure p in and outlet pressure p out of the main sintering exhaust fan, and the inlet flue gas temperature T of the main sintering exhaust fan.

[0025] In the present invention, in step 2), automatically collect the rated flow rate V of the main exhaust fan by the sintering central control system, and calculate the flue gas flow rate Q under the working condition of the main sintering exhaust fan 工 . That is:

[0026] Q 工 = (1000 × P t × (η t + 0.1 × V)) / (k p×(p out -p in ))×3600…(Equation 4).

[0027] In the formula: η t The efficiency is the baseline fan efficiency. 0.1×V is the floating fan efficiency, where 0.1×V is in units of 1. k p This is the compressibility correction factor.

[0028] In this invention, in step 3), the operating flue gas flow rate Q of the sintering main exhaust fan is... 工 Standard flue gas flow rate Q converted to sintering main exhaust fan 标 That is, we get:

[0029] Q 标 =Q 工 ×298 / (273+T)×(101+p in / 1000) / 101…(Equation 5).

[0030] In this invention, in step 4), the sintering control system automatically collects the moisture content Mc of the sintering mixture, calculates the standard flue gas flow rate of the main sintering exhaust fan after deducting water vapor, and combines it with the theoretical sintering air volume of the sintering material during normal production to calculate the total air leakage rate LR of the sintering-dust removal system. 烧-尘 Therefore, we get:

[0031] LR 烧-尘 =((Q) 标 -M c ×(m1+m2+m4)×22.4×10 3 / 18) / (V 标 ×M)-1)×100%…(Equation 6).

[0032] In the formula: V 标 This represents the theoretical sintering air volume per unit of sintering material during normal production.

[0033] In this invention, in step 5), oxygen concentration measuring instruments are respectively installed at the inlet and outlet of the sintering dust collector to obtain the oxygen content ρ in the flue gas at the inlet of the dust collector. 氧in The oxygen content ρ in the flue gas at the dust collector outlet 氧out The air leakage rate (LR) of the dust removal system is calculated using the oxygen balance algorithm. 尘 Therefore, we get:

[0034] LR 尘 =(ρ 氧out -ρ 氧in ) / (ρ 氧air -ρ 氧in )×100%…(Equation 7).

[0035] In the formula: ρ氧air ρ represents the oxygen content in the atmosphere. 氧air =21%.

[0036] In this invention, in step 6), the standard flue gas flow rate Q of the sintering main exhaust fan is determined. 标 Air leakage rate (LR) of dust removal system 尘 The actual sintering air volume passing through the sintering system, after deducting water vapor, is calculated. Combined with the theoretical sintering air volume of the sintered material during normal production, the total air leakage rate LR of the sintering-dust removal system is calculated. 烧 Therefore, we get:

[0037] LR 烧 =((Q) 标 / (1+LR 尘 )-M c ×(m1+m2+m4)×22.4×10 3 / 18) / (V 标 ×M)-1)×100%…(Equation 8).

[0038] This enables online monitoring of the overall air leakage rate of the sintering-dust removal system, the dust removal system, and the sintering system.

[0039] In this invention, when the sintering process is configured with n main exhaust fans (e.g., greater than 180m), 2 When a large-scale sintering production line is typically equipped with two main exhaust fans and n corresponding dust collectors, calculate the power of each main exhaust fan, which is P in sequence. t1 P t2 ...P tn Calculate the flue gas flow rate under operating conditions for each sintering main exhaust fan, as follows: Q 工1 Q 工2 ...Q 工n The operating flue gas flow rate of each sintering main exhaust fan is converted to the standard flue gas flow rate, which is Q. 标1 Q 标2 ...Q 标n Calculate the oxygen content in the flue gas at the inlet and outlet of each dust collector, respectively, as ρ. 氧in1 ρ 氧out1 ρ 氧in2 ρ 氧out2 ...ρ 氧inn ρ oxygen outn .

[0040] At this point, the total air leakage rate of the sintering-dust removal system, the air leakage rate of each dust collector, and the air leakage rate of the sintering system are respectively:

[0041] LR` 烧-尘 =((Q) 标1 +Q 标2 +……Q标n -M c ×(m1+m2+m4)×22.4×10 3 / 18) / (V 标 ×M)-1)×100%…(formula)

[0042] 9).

[0043] LR 尘k =(ρ 氧outk -ρ 氧ink ) / (ρ 氧air -ρ 氧ink )×100%…(Equation 10).

[0044] In the above formula: k represents the kth dust collector.

[0045] LR` 烧 =((Q) 标1 / (1+LR 尘1 )+Q 标2 / (1+LR 尘2 )+……Q 标n / (1+LR 尘n )-M c ×

[0046] (m1+m2+m4)×22.4×10 3 / 18) / (V 标 ×M)-1)×100%…(Equation 11).

[0047] In existing technologies, methods for detecting sintering air leakage rate generally suffer from problems such as long detection cycles, high detection costs, inability to perform real-time online measurement, and low levels of intelligence. Even in limited studies, it is still necessary to install temperature, flue gas composition, and other detection equipment at multiple stages to obtain relevant data, resulting in complex processes and a large workload for equipment maintenance and replacement. To address these shortcomings, this invention proposes an online monitoring method for the entire iron ore sintering system's air leakage rate. This method utilizes the sintering central control system to acquire sintering process parameters under stable production conditions in real time. Without requiring additional detection equipment, it automatically calculates the operating conditions and standard flue gas flow rate of the main sintering exhaust fan (excluding water vapor). By comparing this with the theoretical sintering air volume of the sintered material during normal production, the air leakage rate of the entire sintering system, including sintering and dust removal processes, is obtained in real time. This achieves convenient, fast, and real-time online monitoring of sintering air leakage rate, overcoming the problems of long detection cycles, high detection costs, low levels of intelligence, complex processes, and a large workload for equipment maintenance and replacement associated with existing sintering air leakage rate detection methods.

[0048] In this invention, the online monitoring method for air leakage rate of the entire iron ore sintering system mainly includes the following steps:

[0049] 1) Adjust the sintering production parameters to make the sintering production state stable, and obtain the working condition parameters of the sintering process under the stable state.

[0050] The adjustment of the sintering production parameters described herein, for example, includes parameters in each link such as raw material ratio, moisture content, granulation parameters, feeding, ignition, etc. Generally speaking, controlling the sintering end point at the second last wind box to keep the production state stable for at least 40 minutes (for example, 60 minutes) indicates that the sintering production enters the stable state.

[0051] The obtained sintering working condition parameters under the stable state mainly include the feeding amount m1 of sintering raw materials, the amount m2 of returned ore added, the feeding amount m3 of bedding material, and the water addition amount m4 for sintering, and the sintering material consumption M is calculated according to the formula M = m1 + m2 + m3 + m4.

[0052] When the sintering main exhaust fan is a fixed-frequency fan, these parameters also include the input voltage U, current I, power factor cosΦ of the motor supporting the fixed-frequency main exhaust fan, the efficiency η1 of the motor, and the motor transmission efficiency T e1 , and according to the formula P ta = U×I×√3×cosΦ×η1×T e1 calculate the shaft power P of the fixed-frequency main exhaust fan ta .

[0053] When the sintering main exhaust fan is a variable-frequency fan, these parameters also include the real-time output power P of the frequency converter supporting the variable-frequency main exhaust fan, the efficiency η2 of the supporting motor, and the motor transmission efficiency T e2 , and according to the formula P tb = P×η2×T e2 calculate the shaft power P of the variable-frequency main exhaust fan tb .

[0054] In addition, these parameters also include the inlet pressure p in and outlet pressure p out of the sintering main exhaust fan, the inlet flue gas temperature T of the sintering main exhaust fan, the rated flow V of the sintering main exhaust fan, and the moisture content Mc of the sintered mixture.

[0055] 2) Calculate the working condition flue gas flow of the sintering main exhaust fan.

[0056] According to the principle of flow = power / pressure in the present invention, the working condition flue gas flow Q of the sintering main exhaust fan is calculated by the formula (1000×P t ×(η t + 0.1×V)) / (k p ×(p out - p in ))×3600 工 .

[0057] In the above formula, η t To determine the baseline fan efficiency for the sintering main exhaust fan, based on experience, η t The value is taken as 0.7. The efficiency of the fan is related to its specifications; generally, larger fans are more efficient, while smaller fans are less efficient. Therefore, based on theoretical and practical experience, this application adds a value of 0.1 × V to the formula as the floating fan efficiency of the sintering main exhaust fan. For example, when the rated flow rate V = 0.5 million m³ / s... 3 The efficiency of the main sintering exhaust fan is 0.7 + 0.1 × 0.5 = 0.75 for a small fan with a flow rate of V = 15,000 m³ / min. 3 The efficiency of the small fan ( / min) for the sintering main exhaust fan is taken as 0.7 + 0.1 × 1.5 = 0.85. Furthermore, k p k is the compressibility correction factor. p The value is 0.94.

[0058] 3) Convert the operating flue gas flow rate of the sintering main exhaust fan to the standard flue gas flow rate.

[0059] This invention is based on the principle of the ideal gas law, using formula Q. 标 =Q 工 ×298 / (273+T)×(101+p in / 1000) / 101 will determine the operating flue gas flow rate Q of the sintering main exhaust fan. 工 Converted to standard flue gas flow rate Q 标 .

[0060] During the sintering process, since the exhaust fan typically draws air at room temperature, 298K, or 25℃, is usually set as the standard temperature in the sintering field. Therefore, in the above formula, the standard temperature is 298K.

[0061] 4) Calculate the actual sintering air volume through the main sintering exhaust fan and compare it with the theoretical sintering air volume of the sintering material during normal production to obtain the total air leakage rate of the sintering-dust removal system.

[0062] This invention first calculates the standard flue gas flow rate of the sintering main exhaust fan, after deducting water vapor, based on the moisture content Mc of the sintering mixture. Then, it combines this with the theoretical sintering air volume of the sintering material during normal production, and applies the formula LR. 烧-尘 =((Q) 标 -M c ×(m1+m2+m4)×22.4×10 6 / 18) / (V 标 The total air leakage rate LR of the sintering-dust removal system is calculated as (×M)-1)×100%. 烧-尘Based on experience, the theoretical sintering air volume V per unit of sintered material during normal production (i.e., under stable production conditions) is... 标 The value is 800 Nm 3 / t.

[0063] 5) Obtain the oxygen content in the flue gas at the inlet and outlet of the sintering dust collector, and calculate the air leakage rate of the dust removal system based on the oxygen balance algorithm.

[0064] This application does not require additional testing equipment; it only requires the installation of oxygen concentration measuring instruments at the inlet and outlet of the sintering dust collector. The sintering central control system obtains the oxygen content ρ in the flue gas at the dust collector inlet through the oxygen concentration measuring instruments. 氧in The oxygen content ρ in the flue gas at the dust collector outlet 氧out And according to the oxygen balance algorithm, from the formula LR 尘 =(ρ 氧out -ρ 氧in ) / (ρ 氧air -ρ 氧in ) × 100% to calculate the air leakage rate (LR) of the dust removal system 尘 .

[0065] 6) Calculate the air leakage rate of the sintering system to achieve online monitoring of the air leakage rate of the entire iron ore sintering system.

[0066] This invention is based on the standard flue gas flow rate Q of the sintering main exhaust fan. 标 Air leakage rate (LR) of dust removal system 尘 First, calculate the actual sintering air volume passing through the sintering system after deducting water vapor. Then, combine this with the theoretical sintering air volume of the sintered material during normal production, and apply the formula LR. 烧 =((Q) 标 / (1+LR 尘 )-M c ×(m1+m2+m4)×22.4×10 6 / 18) / (V 标 The total air leakage rate LR of the sintering-dust removal system is calculated as (×M)-1)×100%. 烧 .

[0067] Based on the above process, this invention achieves real-time online monitoring of the leakage rate of the entire sintering-dust removal system, the dust removal system, and the sintering system. Furthermore, the real-time monitoring results are dynamically displayed in the sintering central control system. This invention provides a calibration reference for verifying and calibrating the sintering flue gas volume detection values, while simultaneously enabling real-time dynamic monitoring of the leakage rate of the entire sintering process and its intervals, providing guidance for leakage rate control and equipment maintenance during sinter production.

[0068] Compared with the prior art, the present invention has the following beneficial technical effects:

[0069] (1) The present invention provides an online monitoring method for the leakage rate of the entire iron ore system. Without adding too many other detection equipment, the method uses the sintering control system to obtain some sintering material parameters, sintering ore production parameters, main exhaust fan system operating parameters and some flue gas property detection data in real time. It automatically calculates the sintering flue gas volume under working condition and standard condition after deducting water vapor. By comparing it with the theoretical sintering air volume required by the sintering material under stable production conditions, the leakage rate of the entire sintering system, including the sintering and dust removal processes, is obtained in real time. This achieves the purpose of convenient, fast and real-time online monitoring of the sintering leakage rate, and overcomes the problems of long detection cycle, high detection cost, low level of intelligence and large workload of maintenance and replacement of detection equipment in existing sintering leakage rate detection methods.

[0070] (2) The present invention provides an online monitoring method for the leakage rate of the entire iron ore system. By setting oxygen concentration measuring instruments at the inlet and outlet of the sintering dust collector, the sintering central control system can obtain the O2 concentration or content of the sintering flue gas before and after dust removal in real time, automatically calculate the leakage rate of the dust collector system, and then combine the calculated sintering flue gas flow rate, the theoretical sintering air volume required for sintering materials under stable production conditions and other data to automatically calculate the leakage rate of the sintering machine system, so as to realize the real-time dynamic monitoring of the leakage rate of the sintering machine system and the dust collector system.

[0071] (3) The present invention provides an online monitoring method for the leakage rate of the entire iron ore system. It automatically calculates the sintering flue gas volume using the operating parameters of the main exhaust fan system and some flue gas property detection data. This can provide a reference for monitoring the operating status of the sintering flue gas volume detection device installed in the sintering production system, and overcome the problem that the accuracy of the measurement results cannot be judged due to the long service time, equipment aging or damage of the flue gas volume detection device. Attached Figure Description

[0072] Figure 1 This is a flowchart illustrating an online monitoring method for air leakage rate in an iron ore sintering system according to the present invention.

[0073] Figure 2 This is a schematic diagram showing the location for obtaining the sintering process parameters in this invention. Detailed Implementation

[0074] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0075] Example 1

[0076] A method for online monitoring of air leakage rate in an iron ore sintering system, comprising the following steps:

[0077] 1) Adjust the sintering production parameters to stabilize the sintering production state and obtain the sintering process parameters under stable conditions.

[0078] 2) Calculate the operating flue gas flow rate of the sintering main exhaust fan.

[0079] 3) Convert the operating flue gas flow rate of the sintering main exhaust fan to the standard flue gas flow rate.

[0080] 4) Calculate the actual sintering air volume through the main sintering exhaust fan and compare it with the theoretical sintering air volume of the sintering material during normal production to obtain the total air leakage rate of the sintering-dust removal system.

[0081] Example 2

[0082] A method for online monitoring of air leakage rate in an iron ore sintering system, comprising the following steps:

[0083] 1) Adjust the sintering production parameters to stabilize the sintering production state and obtain the sintering process parameters under stable conditions.

[0084] 2) Calculate the operating flue gas flow rate of the sintering main exhaust fan.

[0085] 3) Convert the operating flue gas flow rate of the sintering main exhaust fan to the standard flue gas flow rate.

[0086] 4) Calculate the actual sintering air volume through the main sintering exhaust fan and compare it with the theoretical sintering air volume of the sintering material during normal production to obtain the total air leakage rate of the sintering-dust removal system.

[0087] 5) Obtain the oxygen content in the flue gas at the inlet and outlet of the sintering dust collector, and calculate the air leakage rate of the dust removal system based on the oxygen balance algorithm.

[0088] Example 3

[0089] like Figure 1 As shown, an online monitoring method for air leakage rate in an iron ore sintering system includes the following steps:

[0090] 1) Adjust the sintering production parameters to stabilize the sintering production state and obtain the sintering process parameters under stable conditions.

[0091] 2) Calculate the operating flue gas flow rate of the sintering main exhaust fan.

[0092] 3) Convert the operating flue gas flow rate of the sintering main exhaust fan to the standard flue gas flow rate.

[0093] 4) Calculate the actual sintering air volume through the main sintering exhaust fan and compare it with the theoretical sintering air volume of the sintering material during normal production to obtain the total air leakage rate of the sintering-dust removal system.

[0094] 5) Obtain the oxygen content in the flue gas at the inlet and outlet of the sintering dust collector, and calculate the air leakage rate of the dust removal system based on the oxygen balance algorithm.

[0095] 6) Calculate the air leakage rate of the sintering system to achieve online monitoring of the air leakage rate of the entire iron ore sintering system.

[0096] Example 4

[0097] An online monitoring method for the air leakage rate of the entire iron ore sintering system, the method comprising the following steps:

[0098] 1) Adjust the sintering production parameters to make the sintering production state stable. As Figure 2 shown, obtain the sintering process condition parameters under the stable state, specifically including the following sub-steps:

[0099] ① Calculate the sintering material consumption: Automatically collect the feeding amount m1 of the sintering raw materials, the returned ore input amount m2, the bedding feeding amount m3, and the sintering water addition amount m4 by the sintering central control system, and calculate the sintering material consumption M. That is:

[0100] M = m1 + m2 + m3 + m4.

[0101] ② Calculate the power P of the main sintering exhaust fan t [[ID= 23]]:

[0102] The main sintering exhaust fan is a constant-frequency fan, and automatically collect the input voltage U, current I, power factor cosΦ, efficiency η1 of the motor supporting the constant-frequency main exhaust fan, and motor transmission efficiency T e1 by the sintering central control system, and calculate the shaft power P ta of the constant-frequency main sintering exhaust fan. That is:

[0103] P ta = U×I×√3×cosΦ×η1×T e1 .

[0104] ③ Automatically collect the inlet pressure p in and outlet pressure p out of the main sintering exhaust fan, and the inlet flue gas temperature T of the main sintering exhaust fan by the sintering central control system.

[0105] 2) Calculate the flue gas flow rate under the working condition of the main sintering exhaust fan.

[0106] Automatically collect the rated flow rate V of the main exhaust fan by the sintering central control system, and calculate the flue gas flow rate Q 工 under the working condition of the main sintering exhaust fan. That is:

[0107] Q 工 = (1000×P t ×(η t + 0.1×V)) / (k p ×(p out - p in ))×3600.

[0108] In the formula: η t η is the baseline wind turbine efficiency. t =0.7. 0.1×V is the floating fan efficiency, and the unit of 0.1×V is 1 kJ. p k is the compressibility correction factor. p =0.94.

[0109] 3) The operating flue gas flow rate Q of the sintering main exhaust fan 工 Converted to standard flue gas flow rate Q 标 That is, we get:

[0110] Q 标 =Q 工 ×298 / (273+T)×(101+p in / 1000) / 101.

[0111] 4) Calculate the actual sintering air volume through the main sintering exhaust fan and compare it with the theoretical sintering air volume of the sintering material during normal production to obtain the total air leakage rate of the sintering-dust removal system.

[0112] The sintering control system automatically collects the moisture content Mc of the sintering mixture, calculates the standard flue gas flow rate of the main sintering exhaust fan after deducting water vapor, and combines this with the theoretical sintering air volume of the sintering material during normal production to calculate the total air leakage rate LR of the sintering-dust removal system. 烧-尘 Therefore, we get:

[0113] LR 烧-尘 =((Q) 标 -M c ×(m1+m2+m4)×22.4×10 3 / 18) / (V 标 ×M)-1)×100%.

[0114] In the formula: V 标 V represents the theoretical sintering air volume per unit of sintered material during normal production. 标 =800Nm 3 / t.

[0115] Example 5

[0116] Repeat Example 4, except that in step 1), the sintering main exhaust fan is a variable frequency fan, and the real-time output power P of the variable frequency main exhaust fan's inverter, the efficiency η2 of the matching motor, and the motor transmission efficiency T are automatically collected by the sintering central control system. e2 Calculate the shaft power P of the variable frequency main exhaust fan. tb Therefore, we get:

[0117] P tb =P×η2×T e2 .

[0118] Example 6

[0119] Repeat Example 5, except that the method includes:

[0120] 5) Obtain the oxygen content in the flue gas at the inlet and outlet of the sintering dust collector, and calculate the air leakage rate of the dust removal system based on the oxygen balance algorithm.

[0121] Oxygen concentration measuring instruments are installed at the inlet and outlet of the sintering dust collector to obtain the oxygen content ρ in the flue gas at the dust collector inlet. 氧in The oxygen content ρ in the flue gas at the dust collector outlet 氧out The air leakage rate (LR) of the dust removal system is calculated using the oxygen balance algorithm. 尘 Therefore, we get:

[0122] LR 尘 =(ρ 氧out -ρ 氧in ) / (ρ 氧air -ρ 氧in )×100%.

[0123] In the formula: ρ 氧air ρ represents the oxygen content in the atmosphere. 氧air =21%.

[0124] Example 7

[0125] Repeat Example 6, except that the method further includes:

[0126] 6) Calculate the air leakage rate of the sintering system to achieve online monitoring of the air leakage rate of the entire iron ore sintering system.

[0127] According to the standard flue gas flow rate Q of the sintering main exhaust fan 标 Air leakage rate (LR) of dust removal system 尘 The actual sintering air volume passing through the sintering system, after deducting water vapor, is calculated. Combined with the theoretical sintering air volume of the sintered material during normal production, the total air leakage rate LR of the sintering-dust removal system is calculated. 烧 Therefore, we get:

[0128] LR 烧 =((Q) 标 / (1+LR 尘 )-M c ×(m1+m2+m4)×22.4×10 3 / 18) / (V 标 ×M)-1)×100%.

[0129] This enables online monitoring of the overall air leakage rate of the sintering-dust removal system, the dust removal system, and the sintering system.

[0130] Example 8

[0131] Example 7 is repeated, except that in this example, the sintering process is equipped with two main exhaust fans and two corresponding dust collectors. The power P of each main exhaust fan is calculated. t1 P t2 Calculate the flue gas flow rate Q of each sintering main exhaust fan under operating conditions. 工1 Q 工2 The operating flue gas flow rate of each sintering main exhaust fan is converted into the standard flue gas flow rate Q. 标1 Q 标2 Calculate the oxygen content in the flue gas at the inlet and outlet of each dust collector, respectively, as ρ. 氧in1 ρ 氧out1 ρ 氧in2 ρ 氧out2 .

[0132] At this point, the total air leakage rate of the sintering-dust removal system, the air leakage rate of each dust collector, and the air leakage rate of the sintering system are respectively:

[0133] LR` 烧-尘 =((Q) 标1 +Q 标2 -M c ×(m1+m2+m4)×22.4×10 3 / 18) / (V 标 ×M)-1)×100%.

[0134] LR 尘1 =(ρ 氧out1 -ρ 氧in1 ) / (ρ 氧air -ρ 氧in1 )×100%.

[0135] LR 尘2 =(ρ 氧out2 -ρ 氧in2 ) / (ρ 氧air -ρ 氧in2 )×100%.

[0136] LR` 烧 =((Q) 标1 / (1+LR 尘1 )+Q 标2 / (1+LR 尘2 )-M c ×(m1+m2+m4)×22.4×10 3 / 18) / (V 标

[0137] ×M)-1)×100%.

[0138] Application Example 1

[0139] The method described in Example 8 was applied to a newly built sintering production line with a scale of 330 m 2 In this sintering production line, the main exhaust fan of sintering is configured with two variable-frequency fans in parallel, and two dust collectors are correspondingly set. The total air leakage rate, the air leakage rate of the dust removal system, and the air leakage rate of the sintering system of the sintering-dust removal system of this production line were detected online. The specific process is as follows:

[0140] 1) Adjust the process parameters of sintering production, including raw material ratio, moisture content, granulation parameters, cloth laying, ignition and other parameters of each link, so that the sintering end point is controlled at the second last air box, and keep the production state stable for 60 min. Obtain the process parameters of the sintering process under the stable state, which specifically include the following sub-steps:

[0141] ① Calculate the consumption of sintering materials: The sintering raw material feeding amount m1 = 670 t / h, the return ore blending amount m2 = 90 t / h, the bottom material feeding amount m3 = 100 t / h, and the sintering water addition amount m4 = 30 t / h were automatically collected by the sintering central control system. The sintering material consumption M = m1 + m2 + m3 + m4 = 890 t / h was calculated.

[0142] ② Calculate the power P of the main exhaust fan of sintering t : The real-time output powers of the frequency converters supporting the two variable-frequency main exhaust fans of sintering, P1 = 4694.75 kW / h and P2 = 5152.17 kW / h, and the motor efficiency η = 0.96 and the motor transmission efficiency T e = 0.98 were automatically collected by the sintering central control system. Through the formula P t = P×η×T e The shaft powers of the two main exhaust fans were calculated to be P t1 = 4416.82 kW and P t2 = 4847.17 kW respectively.

[0143] ③ The inlet pressure p in and the outlet pressure p out of the two main exhaust fans of sintering, and the inlet flue gas temperature T of the two main exhaust fans of sintering were automatically collected by the sintering central control system: p in1 = -18160 Pa, p in1 = -18350 Pa, p out1 = -500 Pa, p out2 = -500 Pa, T1 = 143 °C, T2 = 147 °C. [[ID=~41]]

[0144] 2) Calculate the flue gas flow rate under the working conditions of the main exhaust fan of sintering:

[0145] The rated flow rate V = 0.5×10^4 m 3 / min of the two main exhaust fans was automatically collected by the sintering central control system. According to the formula Q 工=(1000×P) t ×(η t +0.1×V)) / (k p ×(p out -p in Calculate the flue gas flow rate Q of the two sintering main exhaust fans under operating conditions by multiplying by 3600. 工 , obtain Q 工1 =718381.4m 3 / h、Q 工2 =779983.8m 3 / h.

[0146] 3) Convert the operating flue gas flow rate of the sintering main exhaust fan to the standard flue gas flow rate:

[0147] According to formula Q 标 =Q 工 ×298 / (273+T)×(101+p in Calculate the standard flow rate Q of the sintering flue gas from the two main exhaust fans ( / 1000) / 101. 标 , obtain Q 标1 =422081.9 Nm 3 / h、Q 标2 =452870.5Nm 3 / h.

[0148] 4) Calculate the actual sintering air volume through the main sintering exhaust fan and compare it with the theoretical sintering air volume of the sintering material during normal production to obtain the total air leakage rate of the sintering-dust removal system.

[0149] The moisture content M of the sintering mixture is automatically collected by the sintering control system. c =7.0%, according to the formula LR 烧-尘 =((Q) 标1 +Q 标2 -M c ×(m1+m2+m4)×22.4×10 3 / 18) / (V 标 Calculate the total air leakage rate of the sintering-dust removal system by (×M)-1)×100%, and obtain LR. 烧-尘 =13.23%.

[0150] 5) Obtain the oxygen content in the flue gas at the inlet and outlet of the sintering dust collector, and calculate the air leakage rate of the dust removal system based on the oxygen balance algorithm.

[0151] Oxygen concentration measuring instruments were installed at the inlet and outlet of two sintering dust collectors, and the O2 content ρ in the flue gas at the inlet and outlet of the two dust collectors was automatically collected by the sintering central control system. 氧in and ρ 氧out , obtain ρ 氧in1=13.53%, ρ 氧in2 =13.41%, ρ 氧out1 =13.64%, ρ 氧out2 =13.57%, according to the formula LR 尘 =(ρ 氧out -ρ 氧in ) / (ρ 氧air -ρ 氧in ) × 100% to calculate the air leakage rate (LR) of the dust removal system 尘 , obtain LR 尘1 =1.47% and LR 尘2 =2.11%.

[0152] 6) Calculate the air leakage rate of the sintering system to achieve online monitoring of the air leakage rate of the entire iron ore sintering system.

[0153] According to the standard flue gas flow rate Q of the sintering main exhaust fan 标 Air leakage rate (LR) of dust removal system 尘 Calculate the actual sintering air volume passing through the sintering system after deducting water vapor, and combine it with the theoretical sintering air volume of the sintering material during normal production, according to the formula LR 烧 =((Q) 标1 / (1+LR 尘1 )+Q 标2 / (1+LR 尘2 )-M c ×(m1+m2+m4)×22.4×10 3 / 18) / (V 标 Calculate the air leakage rate LR of the sintering system using (×M)-1)×100%. 烧 , obtain LR 烧 =11.05%.

[0154] Through the above process, the sintering central control system automatically obtained the total air leakage rate of the sintering-dust removal system of the production line as 13.23%, the air leakage rate of the dust removal system as 1.47% to 2.11%, and the air leakage rate of the sintering system as 11.05%. The results are displayed in the sintering central control system and change in real time with the changes of each parameter, realizing online monitoring of the air leakage rate of the entire system in the sintering production process.

Claims

1. A method for online monitoring of air leakage rate in an iron ore sintering system, comprising the following steps: 1) Adjust the sintering production parameters to stabilize the sintering production state and obtain the sintering process parameters under stable conditions. Specifically, it includes the following sub-steps: ① Calculate sintering material consumption: The sintering control system automatically collects the sintering raw material feeding amount m1, return ore feeding amount m2, bottom material feeding amount m3, and sintering water addition amount m4, and calculates the sintering material consumption M; that is: M = m1 + m2 + m3 + m4… (Equation 1); ② Calculate the power of the sintering main exhaust fan. P t : When the sintering main exhaust fan is a fixed-frequency fan, the sintering central control system automatically collects the input voltage of the motor supporting the fixed-frequency main exhaust fan U , current I , power factor cosΦ of the motor, efficiency η1 of the motor, and motor transmission efficiency T e1 , and calculates the shaft power of the fixed-frequency main exhaust fan P ta ; that is: … (Equation 2); When the sintering main exhaust fan is a variable frequency fan, the sintering central control system automatically collects the real-time output power of the variable frequency drive connected to the main exhaust fan. P 1. Efficiency η2 of the matching motor; 2. Motor transmission efficiency T e2 Calculate the shaft power of the variable frequency main exhaust fan. P tb ;Right now have to: P tb =P×η2×T e2 … (Equation 3); ③ The inlet pressure of the sintering main exhaust fan is automatically collected by the sintering central control system. p in and export pressure p out 1. Sintering main exhaust fan inlet flue gas temperature T; 2) Calculate the operating flue gas flow rate of the sintering main exhaust fan; The sintering central control system automatically collects the rated flow rate V of the main exhaust fan and calculates the operating flue gas flow rate Q of the main exhaust fan. 工 That is, we get: Q 工 =(1000× P t ×(η t +0.1×V)) / (k p ×( p out - p in ))×3600… (Equation 4); In the formula: η t The efficiency is the baseline for the wind turbine. 0.1×V represents the efficiency of the floating fan, with units of 1; k p This is the compressibility correction factor; 3) The operating flue gas flow rate Q of the sintering main exhaust fan 工 Standard flue gas flow rate Q converted to sintering main exhaust fan 标 ; Q 标 =Q 工 ×298 / (273+T)×(101+ p in / 1000) / 101… (Formula 5); 4) Calculate the actual sintering air volume through the main sintering exhaust fan and compare it with the theoretical sintering air volume of the sintering material during normal production to obtain the total air leakage rate of the sintering-dust removal system. The sintering control system automatically collects the moisture content Mc of the sintering mixture, calculates the standard flue gas flow rate of the main sintering exhaust fan after deducting water vapor, and combines this with the theoretical sintering air volume of the sintering material during normal production to calculate the total air leakage rate LR of the sintering-dust removal system. 烧-尘 That is, we get: LR 烧-尘 =((Q 标 -M c ×(m1+m2+m4)×22.4×10 3 / 18) / (V 标 (×M)-1)×100%… (Equation 6); In the formula: V 标 This represents the theoretical sintering air volume per unit of sintering material during normal production.

2. The method according to claim 1, characterized in that: The method also includes: 5) Obtain the oxygen content in the flue gas at the inlet and outlet of the sintering dust collector, and calculate the air leakage rate of the dust removal system based on the oxygen balance algorithm.

3. The method according to claim 2, characterized in that: The method also includes: 6) Calculate the air leakage rate of the sintering system to achieve online monitoring of the air leakage rate of the entire iron ore sintering system.

4. The method according to claim 3, characterized in that: In step 5), oxygen concentration measuring instruments are installed at the inlet and outlet of the sintering dust collector to obtain the oxygen content ρ in the flue gas at the inlet of the dust collector. 氧in The oxygen content ρ in the flue gas at the dust collector outlet 氧out The air leakage rate (LR) of the dust removal system is calculated using the oxygen balance algorithm. 尘 That is, we get: LR 尘 = (ρ 氧out - ρ 氧in ) / (ρ 氧air - ρ 氧in ) × 100%… (Equation 7); In the formula: ρ 氧air ρ represents the oxygen content in the atmosphere. 氧air =21%.

5. The method according to claim 4, characterized in that: In step 6), the standard flue gas flow rate Q of the sintering main exhaust fan is determined. 标 Air leakage rate (LR) of dust removal system 尘 The actual sintering air volume passing through the sintering system, after deducting water vapor, is calculated. Combined with the theoretical sintering air volume of the sintering material during normal production, the total air leakage rate LR of the sintering system is calculated. 烧 That is, we get: LR 烧 =((Q 标 / (1 + LR 尘 ) - M c ×(m1 + m2 + m4)×22.4×10 3 / 18) / (V 标 ×M)-1)×100%… (Equation 8); This enables online monitoring of the overall air leakage rate of the sintering-dust removal system, the dust removal system, and the sintering system.

6. The method according to claim 5, characterized in that: When the sintering process is configured with n main exhaust fans and n corresponding dust collectors, calculate the power of each main exhaust fan, in the following order: P t1 , P t2 ... P tn Calculate the flue gas flow rate under operating conditions for each sintering main exhaust fan, in order as Q 工1 Q 工2 ...Q 工n The operating flue gas flow rate of each sintering main exhaust fan is converted to the standard flue gas flow rate, which is Q. 标1 Q 标2 ...Q 标n Calculate the oxygen content in the flue gas at the inlet and outlet of each dust collector, respectively, as ρ 氧in1 ρ 氧out1 ρ 氧in2 ρ 氧out2 ...ρ 氧inn ρ 氧outn ; At this point, the total air leakage rate of the sintering-dust removal system, the air leakage rate of each dust collector, and the air leakage rate of the sintering system are respectively: LR` 烧-尘 =(( Q 标1 +Q 标2 +……Q 标n -M c ×(m1 + m2 + m4)×22.4×10 3 / 18) / (V 标 ×M) - 1)×100%…(Equation 9); LR 尘k = (ρ 氧outk - ρ 氧ink ) / (ρ 氧air - ρ 氧ink ) × 100%… (Equation 10); In the above formula: k represents the kth dust collector;

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