Local resistance monitoring and valve opening control method for heat accumulator

Abstract

The invention provides a local resistance monitoring and valve opening control method for a heat accumulator, and belongs to the technical field of heat accumulating type combustion. The method comprises the following steps: operating a to-be-measured heat accumulator according to actual production and use time, and fitting the monthly average value of the pressure difference before and after the heat accumulator in each month with the use cumulative month under the condition of fixed air and gas flow to obtain a relation curve of the monthly average value of the pressure difference before and after the heat accumulator to be measured and the use cumulative month; obtaining a mapping relation between the local resistance coefficient increment of the to-be-measured heat accumulator and the monthly average value increment of the front and back pressure differences based on a fluid mechanics principle; calculating the monthly average value of the front and back pressure differences of the to-be-measured heat accumulator in the target month and the local resistance coefficient of the to-be-measured heat accumulator based on the relation curve; determining the monthly average value increment of the front and back pressure differences of the to-be-measured heat accumulator in the target month according to the mapping relation based on the local resistance coefficient of the to-be-measured heat accumulator; and determining a heat accumulator valve opening degree adjusting scheme according to the difference value between the monthly average value increment of the front and back pressure differences of the to-be-measured heat accumulator in the target month and the actual pressure difference.

Description

Technical Field

[0001] This invention relates to the field of regenerative combustion technology, and in particular to a method for monitoring the local resistance of a regenerative body and controlling the valve opening. Background Technology

[0002] Regenerative combustion technology is an energy-saving combustion technology. Regenerative burners are always used in pairs on both sides of the heating furnace. The periodic combustion and exhaust of a pair of burners absorbs residual heat from the flue gas and preheats the combustion air to a high temperature. While one burner is burning, the other burner exhausts flue gas. The exhaust gas passes through the burner body into a regenerator containing a heat storage medium, which heats the medium to a high temperature. Once the heat storage medium is fully heated, the burning burner closes and begins exhausting flue gas, while the exhausting burner begins burning. The combustion air, flowing through the heat storage medium, is heated to a high temperature by the medium. The periodic switching of burner directions corresponds to the periodic absorption and release of heat by the heat storage medium, thus carrying the heat from the flue gas back into the furnace, achieving energy saving and consumption reduction. This technology can fully utilize blast furnace gas, a byproduct of blast furnace ironmaking, thus offering significant energy-saving advantages and avoiding the direct emission of low-calorific-value blast furnace gas into the atmosphere, which would cause serious pollution. This technology is widely used in the rolling mill heating furnaces of various steel enterprises.

[0003] However, due to prolonged production, the pores of the heat storage honeycomb become clogged, increasing the resistance to smoke exhaust and gas supply. Furthermore, as production time extends, the pores gradually decrease, and the resistance continues to change, making combustion control more difficult.

[0004] Therefore, a method for monitoring the local resistance of the heat storage body and controlling the valve opening is needed. Summary of the Invention

[0005] In view of this, the present invention provides a method for monitoring the local resistance of a heat storage body and controlling the valve opening. By simulating the actual combustion environment on site, the method monitors and analyzes the change law of the pore resistance of the heat storage body as the usage time increases, and adjusts the valve opening accordingly to ensure stable combustion.

[0006] Therefore, the present invention provides the following technical solution: A method for monitoring the local resistance of a heat storage body and controlling the valve opening includes: The heat storage body under test is operated according to the actual production and usage time. Under the condition of fixed air and coal flow rate, the monthly average pressure difference before and after the heat storage body is fitted with the cumulative months of use to obtain the relationship curve between the monthly average pressure difference before and after the heat storage body under test and the cumulative months of use. Based on the principle of fluid mechanics, the mapping relationship between the increment of the local resistance coefficient of the heat storage body under test and the increment of the monthly average pressure difference before and after the test is obtained. Based on the aforementioned relationship curve, calculate the monthly average pressure difference before and after the test heat storage body in the target month and the local resistance coefficient of the test heat storage body; Based on the mapping relationship, determine the monthly average increment of the pressure difference before and after the test heat storage body in the target month according to the local resistance coefficient of the test heat storage body; The valve opening adjustment scheme for the heat storage body is determined based on the difference between the monthly average increment of the pressure difference before and after the heat storage body in the target month and the actual pressure difference.

[0007] Furthermore, the relationship curve between the monthly average pressure difference before and after the heat storage body under test and the cumulative number of months of use is as follows:

[0008] in, For cumulative months, This represents the monthly average pressure difference before and after the heat storage body being tested. and represents the fitting coefficient.

[0009] Furthermore, the mapping relationship between the increment of the local resistance coefficient of the heat storage body under test and the monthly average increment of the pressure difference before and after is as follows:

[0010] in, This represents the monthly average pressure difference before and after the heat storage body being tested. The local resistance coefficient of the heat storage body under test is denoted as . The coefficients are set according to the actual working conditions.

[0011] Furthermore, the step of determining the valve opening adjustment scheme for the thermal storage body based on the difference between the monthly average increment of the pressure difference before and after the target month and the actual pressure difference includes: The adjustment threshold is determined based on actual production experience; The valve opening adjustment scheme for the heat storage body is determined by comparing the monthly average increase of the pressure difference before and after the target month with the actual pressure difference and the adjustment threshold.

[0012] Furthermore, the valve opening adjustment scheme for the heat storage body includes: If the difference between the monthly average increment of the pressure difference before and after the target heat storage body in the target month and the actual pressure difference is less than or equal to the adjustment threshold, the opening of the heat storage body valve will not be adjusted. If the difference between the monthly average increment of the pressure difference across the target heat storage body and the actual pressure difference is greater than the adjustment threshold, the opening of the heat storage body valve is increased until the difference between the monthly average increment of the pressure difference across the target heat storage body and the actual pressure difference is less than or equal to the adjustment threshold.

[0013] Furthermore, the step of obtaining the mapping relationship between the increment of the local resistance coefficient of the heat storage body under test and the monthly average increment of the pressure difference before and after, based on the principles of fluid mechanics, includes: The local resistance coefficient of the heat storage body is calculated using fluid dynamics principles, and the formula is as follows:

[0014] in, This represents the local resistance coefficient of the heat storage body. Indicates fluid flow rate m 3 / s, Expressing fluid density in kg / m³ 3 , The temperature is ℃. It is 1 / 273.

[0015] Advantages and positive effects of the present invention: This method constructs a curve showing the relationship between the monthly average pressure difference before and after the test heat storage body and the cumulative number of months of use. Based on fluid mechanics principles, it obtains the mapping relationship between the increment of the local resistance coefficient of the test heat storage body and the increment of the monthly average pressure difference before and after the test. This effectively detects the change in local resistance loss of the heat storage body as the usage time increases. It enables the determination of the heat storage body valve opening adjustment scheme based on the difference between the monthly average increment of the pressure difference before and after the test heat storage body in the target month and the actual pressure difference. By controlling the valve opening, the problem of combustion instability caused by resistance changes is overcome. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the experimental apparatus corresponding to the local resistance monitoring method of the heat storage body in this embodiment of the invention; Figure 2 This is a flowchart of the method for monitoring the local resistance of the heat storage body and controlling the valve opening in an embodiment of the present invention; In the diagram: 1. Nozzle pressure test hole; 2. Pressure test hole in front of the regenerator; 3. Furnace; 4. Air regenerator; 5. Gas regenerator; 6. Gas and flue gas pipeline; 7. Air and flue gas pipeline; 8. Reversing valve; 9. Air pipeline regulating valve; 10. Air and flue gas regulating valve; 11. Gas pipeline regulating valve; 12. Gas and flue gas regulating valve; 13. Ignition burner. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0019] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0020] like Figure 1 As shown, pressure measuring devices are added before and after the heat storage body, and air / gas regulating valves and flue gas valves for individual heat storage bodies are added to the on-site production unit as an experimental device. The experimental device includes: nozzle pressure measuring hole 1, pressure measuring hole before the heat storage body 2, furnace 3, air heat storage body 4, gas heat storage body 5, gas and flue gas pipelines 6, air and flue gas pipelines 7, reversing valve 8, air pipeline regulating valve 9, air and flue gas regulating valve 10, gas pipeline regulating valve 11, gas and flue gas regulating valve 12, and ignition burner 13.

[0021] Combination Figure 2 As shown, the method for monitoring the local resistance of the heat storage body and controlling the valve opening includes the following steps: Step 1: Place the heat storage body to be tested into the burner cavity.

[0022] Step 2: Turn on the ignition burner to raise the temperature. When the temperature reaches the blast furnace gas ignition temperature, turn on the regenerative burner to start combustion and record the pressure difference across the regenerative body when the regenerative burner starts to burn.

[0023] Step 3: Operate the test device according to the actual operating parameters on site, and record the pressure difference before and after the heat storage body every day, and calculate the monthly average value.

[0024] Step 4: The experimental setup is operated according to actual production usage time. Under a fixed air-coal gas flow rate, the monthly average pressure difference before and after the heat storage body is fitted with the cumulative number of months of use to obtain the relationship curve between the monthly average pressure difference before and after the heat storage body and the cumulative number of months of use:

[0025] in, For cumulative months, This represents the monthly average pressure difference before and after the heat storage body being tested. and represents the fitting coefficient.

[0026] Step 5: Based on the monthly average pressure difference measured before and after the heat storage body, calculate the local resistance coefficient of the heat storage body using fluid dynamics principles.

[0027] in, This represents the local resistance coefficient of the heat storage body. Indicates fluid velocity in m / s. Expressing fluid density in kg / m³ 3 , The temperature is ℃. It is 1 / 273.

[0028] Under otherwise constant conditions, the local resistance coefficient of the thermal storage body is affected by the monthly average pressure difference across the body. By fitting the monthly average pressure difference across the body to the local resistance coefficient over time, a relationship curve can be obtained: +N in, And N are constants.

[0029] Step 6, assuming all other conditions remain unchanged, Increment and Incremental mapping relationship:

[0030] make for For a fixed operating condition, k is a constant, so the above formula becomes:

[0031] Step 7: Based on the mapping relationship in Step 6, determine the monthly average increment of the pressure difference before and after the test heat storage body in the target month according to the local resistance coefficient of the test heat storage body; The valve opening adjustment scheme for the heat storage body is determined based on the difference between the monthly average increment of the pressure difference before and after the heat storage body in the target month and the actual pressure difference.

[0032] Example 1 Methods based on monitoring the local resistance of the heat storage body and controlling valve opening include: Step 1: Place the heat storage body to be tested into the burner cavity.

[0033] Step 2: Turn on the ignition burner to raise the temperature. When the temperature reaches the blast furnace gas ignition temperature, turn on the regenerative burner to start combustion and record that the pressure difference across the regenerative body is 30 Pa when the regenerative burner starts to burn.

[0034] Step 3: Operate the experimental device according to the actual on-site operating parameters, and record the pressure difference before and after the heat storage body daily, and calculate the monthly average value. Step 4: Run the experimental device according to the actual production usage time. Under the condition of a fixed air-coal flow rate, fit the monthly average pressure difference before and after the heat storage body with the cumulative number of months of use to obtain the relationship curve between the monthly average pressure difference before and after the heat storage body and the cumulative number of months of use:

[0035] in, This represents the monthly average pressure difference before and after the heat storage body. To use cumulative months.

[0036] Step 5: Based on the monthly average pressure difference measured before and after the heat storage body, calculate the local resistance coefficient of the heat storage body using fluid dynamics principles. The formula is as follows:

[0037] in, This represents the local resistance coefficient of the heat storage body. Indicates fluid velocity in m / s. Expressing fluid density in kg / m³ 3 , The temperature is ℃. It is 1 / 273.

[0038] Under otherwise constant conditions, the local resistance coefficient of the thermal storage body is affected by the monthly average pressure difference across the thermal storage body. Therefore, by fitting the monthly average pressure difference across the thermal storage body to the local resistance coefficient over time, a relationship curve can be obtained:

[0039] Step 6: Under the condition that other factors remain unchanged, the monthly average increase in the pressure difference before and after the heat storage body is linearly related to the increase in the local resistance coefficient of the heat storage body.

[0040] make,

[0041] Let k be a constant value of 12.718 for the fixed operating condition. Therefore:

[0042] Step 7: When the heat storage body has been used for 7 months, the experimental test shows that the increase in the local resistance coefficient of the heat storage body is 2.752. The formula in Step 6 shows that the monthly average increase in the pressure difference before and after the heat storage body is 35, and the actual pressure difference is 30. The difference between the two is ≤20pa, so there is no need to adjust the valve opening.

[0043] Example 2 Based on the same steps as in Example 1, when the heat storage body is used for 8 months, the experimental test shows that the increase in the local resistance coefficient of the heat storage body is 3.302; the formula in step 6 shows that the monthly average increase in the pressure difference before and after the heat storage body is 42, the actual pressure difference is 10, and the difference between the two is ≥20pa. Then, the valve opening is increased by 2%, and the actual pressure difference is repeatedly detected until the difference between the two is ≤20pa.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of monitoring local resistance of a regenerator and controlling valve opening, characterized by, The method comprises: running the to-be-tested heat accumulator according to actual production time, fitting the monthly average pressure difference before and after the to-be-tested heat accumulator with the cumulative months of use under the condition of fixed air flow, obtaining a relationship curve of the monthly average pressure difference before and after the to-be-tested heat accumulator with the cumulative months of use, and obtaining a mapping relationship between the local resistance coefficient increment of the to-be-tested heat accumulator and the monthly average pressure difference increment based on the principle of fluid mechanics; calculating the monthly average pressure difference before and after the to-be-tested heat accumulator and the local resistance coefficient of the to-be-tested heat accumulator in the target month based on the relationship curve; determining the monthly average pressure difference before and after the to-be-tested heat accumulator in the target month based on the local resistance coefficient of the to-be-tested heat accumulator according to the mapping relationship; determining the heat accumulator valve opening adjustment scheme according to the difference between the monthly average pressure difference before and after the to-be-tested heat accumulator in the target month and the actual pressure difference.

2. The method of claim 1, wherein, The relationship curve of the monthly average pressure difference before and after the to-be-tested heat accumulator with the cumulative months of use: wherein, is the cumulative month, is the monthly average of the pressure difference before and after the heat accumulator to be tested, and is the fitting coefficient.

3. The method of claim 1, wherein, The mapping relationship between the local resistance coefficient increment of the to-be-tested heat accumulator and the monthly average pressure difference increment: wherein, is the monthly average of the pressure difference before and after the heat accumulator to be measured, is the local resistance coefficient of the heat accumulator to be measured, is the coefficient set according to the actual working condition.

4. The method of claim 1, wherein, The determination of the heat accumulator valve opening adjustment scheme according to the difference between the monthly average pressure difference before and after the to-be-tested heat accumulator in the target month and the actual pressure difference comprises: determining an adjustment threshold based on actual production experience; comparing the difference between the monthly average pressure difference before and after the to-be-tested heat accumulator in the target month and the actual pressure difference with the adjustment threshold to determine the heat accumulator valve opening adjustment scheme.

5. The method of claim 4, wherein, The heat accumulator valve opening adjustment scheme comprises: when the difference between the monthly average pressure difference before and after the to-be-tested heat accumulator in the target month and the actual pressure difference is less than or equal to the adjustment threshold, the heat accumulator valve opening is not adjusted; when the difference between the monthly average pressure difference before and after the to-be-tested heat accumulator in the target month and the actual pressure difference is greater than the adjustment threshold, the heat accumulator valve opening is increased until the difference between the monthly average pressure difference before and after the to-be-tested heat accumulator in the target month and the actual pressure difference is less than or equal to the adjustment threshold.

6. The method of claim 1, wherein, The determination of the mapping relationship between the local resistance coefficient increment of the to-be-tested heat accumulator and the monthly average pressure difference increment based on the principle of fluid mechanics comprises: calculating the local resistance coefficient of the heat accumulator by the principle of fluid mechanics, which is expressed as: wherein, represents the partial resistance coefficient of the heat accumulator, represents the fluid flow m 3 / s, represents the fluid density kg / m 3 , is the temperature °C, is 1 / 273.

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