A method for controlling oxidation-free in an annealing furnace with open flame heating

Abstract

The embodiment of the specification discloses an annealing furnace open flame heating non-oxidation control method, which is characterized in that: a CO real-time detection analyzer and a dew point analyzer for measuring humidity in the furnace are arranged in the furnace, balance test is carried out on burners in multiple furnace temperature control zones in the non-oxidation furnace, the main air valve in front of the burner is dynamically adjusted according to the carbon monoxide detection value and the residual oxygen detection value, and the dew point value is controlled to be not more than 20 DEG C, so that the oxidation defects generated during the open flame heating of the strip steel can be effectively eliminated and the product quality can be improved under the premise of ensuring that the heating efficiency is not reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat treatment, in particular to an oxidation-free control method for open flame heating of an annealing furnace. BACKGROUND

[0002] The steel rolling annealing furnace is a finished product process for continuous annealing of cold-rolled steel plates, and the open flame heating section is the main part of the annealing furnace. Since the cold-rolled steel plates have strict requirements on surface quality, in order to prevent oxidation defects from occurring during heating of the steel plates, the atmosphere in the open flame heating furnace needs to be strictly controlled. Because the atmosphere in the furnace is complex, the oxidizing atmosphere contains O2, H2O and CO2, and quality defects such as “color difference” and “black spots” often occur during heating of the steel plates, resulting in a large number of unqualified products. Therefore, under the premise of ensuring heating efficiency, how to achieve high-quality oxidation-free heating is a common problem faced by the industry. SUMMARY

[0003] The embodiments of the present application provide an oxidation-free control method for open flame heating of an annealing furnace to solve the above problems existing in the prior art.

[0004] The oxidation-free control method for open flame heating of an annealing furnace provided by the embodiments of the present application configures a carbon monoxide residual oxygen analyzer for real-time detection and a dew point analyzer for measuring the humidity in the furnace in the oxidation-free furnace, and the control method comprises the following steps:

[0005] S101: performing balance test on the burners of multiple furnace temperature control zones in the oxidation-free furnace;

[0006] S102: dynamically adjusting the main air valve in front of the burner according to the carbon monoxide detection value and the residual oxygen detection value;

[0007] S103: controlling the dew point value to be no more than 20℃.

[0008] Optionally, the balance test on the burners of multiple furnace temperature control zones in the oxidation-free furnace comprises:

[0009] obtaining the main air pressure in front of the burners of the furnace temperature control zones; the multiple furnace temperature control zones correspond to multiple main air pressures in front of the burners;

[0010] obtaining the average value of the multiple main air pressures in front of the burners;

[0011] if the deviation degree of the main air pressure in front of the burner from the average value is greater than 3%, the air intake amount and the fuel gas intake amount of the burner are increased or decreased;

[0012] the deviation degree of the main air pressure in front of the burner from the average value is equal to the absolute value of the difference between the main air pressure in front of the burner and the average value divided by the average value.

[0013] Optionally, if the deviation of the main air pressure before the burner from the average value is greater than 3%, the air intake and fuel gas intake of the burner are adjusted to increase or decrease.

[0014] If the main air pressure before the burner is greater than the average value and the deviation is greater than 3%, the air intake and fuel gas intake of the burner are adjusted to decrease.

[0015] If the main air pressure before the burner is less than the average value and the deviation is greater than 3%, the air intake and fuel gas intake of the burner are adjusted to increase.

[0016] Optionally, the dynamic adjustment of the main air valve before the burner according to the carbon monoxide detection value and the residual oxygen detection value comprises:

[0017] The main air valve before the burner is adjusted so that the residual oxygen detection value of each zone of the non-oxidizing furnace is less than or equal to 10 ppm, the carbon monoxide detection value of each zone of the non-oxidizing furnace is greater than or equal to 2000 ppm, the residual oxygen detection value of the preheating furnace is less than or equal to 1%, and the carbon monoxide detection value of the preheating furnace is less than or equal to 100 ppm.

[0018] Optionally, the dynamic adjustment of the main air valve before the burner according to the carbon monoxide detection value and the residual oxygen detection value comprises:

[0019] When the residual oxygen at a certain point in the non-oxidizing furnace is higher than the standard value, the burner with a blue flame or the burner with a greater deviation in the balance test in step S101 is adjusted first, and the residual oxygen and the carbon monoxide content of the preheating furnace are controlled by supplementing air.

[0020] Optionally, the standard value is 10 ppm.

[0021] Optionally, the control of the dew point value is not more than 20℃, comprising:

[0022] The flowability of the atmosphere in the furnace is improved, and the wet atmosphere in the non-oxidizing furnace is discharged faster.

[0023] Optionally, the improvement of the flowability of the atmosphere in the furnace and the acceleration of the discharge of the wet atmosphere in the non-oxidizing furnace comprises:

[0024] The amount of protective gas introduced at the outlet of the annealing furnace and the furnace throat is increased, and the height of the isolation baffle at the furnace throat is increased to improve the flowability and accelerate the discharge of the wet atmosphere.

[0025] Optionally, the method further comprises:

[0026] In step S101, the air and gas flow rates of each temperature control zone of the non-oxidizing furnace are set when the load of the burner is 80%, the pressure before the burner is measured by a differential pressure gauge under this working condition, and the air pressure deviation is adjusted by a scaled hand valve before the burner. If the air pressure deviation is large, the pipeline needs to be disassembled to confirm whether there is a blockage.

[0027] Optionally, the empty gas flow of each furnace temperature control zone of the non-oxidizing furnace is set to be between 100 and 300 cubic meters; and the air pressure deviation is greater than 7%.

[0028] The beneficial effects of the embodiments of the present specification are as follows:

[0029] The embodiments of the present specification provide a non-oxidizing control method for open flame heating of an annealing furnace. A CO (carbon monoxide) real-time detection residual oxygen analyzer and a dew point analyzer for measuring the humidity in the furnace are arranged in the furnace. The burners in the multiple furnace temperature control zones of the non-oxidizing furnace are balanced tested. The main air valve in front of the burners is dynamically adjusted according to the carbon monoxide detection value and the residual oxygen detection value. The dew point value is controlled to be less than 20℃. The oxidation defects generated during the open flame heating of the strip steel can be effectively eliminated, and the product quality can be improved without reducing the heating efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0030] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not intended to limit the scope of the present specification. Moreover, the same reference numerals are used throughout the same figures. In the drawings:

[0031] Figure 1 A non-oxidizing control method for open flame heating of an annealing furnace is provided for the embodiments of the present specification.

[0032] Figure 2 A schematic diagram of an open flame burner is provided for the embodiments of the present specification.

[0033] Figure 3 A schematic diagram of the introduction of protective gas into an annealing furnace is provided for the embodiments of the present specification.

[0034] The drawings identify: 1-gas inlet structure; 2-burning air inlet structure; 3-burning structure; 4-gas inlet channel. DETAILED DESCRIPTION

[0035] In order to better understand the above technical solutions, the technical solutions of the embodiments of the present specification will be described in detail below with the help of the drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present specification and the embodiments are detailed descriptions of the technical solutions of the present specification, and are not limitations of the technical solutions of the present specification. In the case of no conflict, the technical features in the embodiments of the present specification and the embodiments can be combined with each other.

[0036] Embodiment 1

[0037] As Figure 1As shown, the embodiment of the present application provides an annealing furnace open flame heating non-oxidation control method, a carbon monoxide residual oxygen analyzer for real-time detection and a dew point analyzer for measuring humidity in the furnace are arranged in the non-oxidation furnace, and the control method comprises the following steps:

[0038] S101: balance test is performed on the burners in multiple furnace temperature control zones in the non-oxidation furnace.

[0039] Wherein, the main air pressure before the burner is measured in the cold state, and the pressure difference before and after the main coal gas throttle orifice plate before the burner is measured in the hot state, so as to ensure that the deviation is less than or equal to 3%. When the burner load is 80%, the air- coal gas flow rate of each zone is set, and the pressure before the burner is measured under this working condition by using a differential pressure gauge. When the air pressure deviation is large, the pipeline needs to be disassembled to confirm whether there is a blockage.

[0040] S102: dynamically adjusting the main air valve before the burner according to the carbon monoxide detection value and the residual oxygen detection value.

[0041] Wherein, the residual oxygen of each zone in the non-oxidation furnace is controlled to be less than or equal to 10 ppm, and the CO content is greater than or equal to 2000 ppm; the residual oxygen of the preheating furnace is less than or equal to 1%, and the CO content is less than or equal to 100 ppm. When the residual oxygen of a certain point in the non-oxidation furnace is higher than the standard, the burners with a blue flame or a large deviation during the combustion balance test are preferentially adjusted, and the residual oxygen and the CO content of the preheating furnace are controlled by supplementing air.

[0042] S103: controlling the dew point value to be less than or equal to 20℃.

[0043] Specifically, the flowability of the atmosphere in the furnace is improved, and the wet atmosphere in the non-oxidation furnace is discharged quickly by increasing the amount of protective gas introduced at the outlet and the furnace throat of the annealing furnace, and increasing the height of the isolation baffle at the furnace throat. The flowability is improved, and the wet atmosphere is discharged quickly.

[0044] By adopting the above scheme, by arranging the CO and residual oxygen analyzers for real-time detection and the dew point analyzer for measuring the humidity in the furnace, the control requirements and measures of the oxidizing atmosphere in the non-oxidation furnace are proposed. On the premise of ensuring that the heating efficiency is not reduced, the oxidation defects generated during the open flame heating of the strip steel are effectively eliminated, and the product quality is improved. By the balance test of the burners, the combustion state of the burners is optimized, and in addition, by using the atmosphere analyzer arranged on the production line, the atmosphere in the furnace is dynamically adjusted, and the oxidation in the furnace is improved. In the aspect of patent novelty, the atmosphere composition is complex during the open flame heating, and the non-oxidation control of the strip steel at high temperature belongs to an industry-level difficult problem.

[0045] Embodiment 2

[0046] In the embodiment of the present application, an annealing furnace open flame heating non-oxidation control method is provided, comprising the following steps:

[0047] S201: balance test is performed on the burners in the multiple furnace temperature control zones in the non-oxidizing furnace;

[0048] S202: dynamically adjusting the burner front main air valve according to the carbon monoxide detection value and the residual oxygen detection value;

[0049] S203: controlling the dew point value to be no more than 20°C.

[0050] The balance test on the burners in the multiple furnace temperature control zones in the non-oxidizing furnace comprises:

[0051] obtaining the burner front main air pressure of the furnace temperature control zone; the multiple furnace temperature control zones correspond to multiple burner front main air pressures;

[0052] obtaining the average value of the multiple burner front main air pressures;

[0053] if the deviation degree of the burner front main air pressure from the average value is greater than 3%, the air intake and the fuel gas intake of the burner are increased or decreased;

[0054] The deviation degree of the burner front main air pressure from the average value is equal to the absolute value of the difference between the burner front main air pressure and the average value divided by the average value.

[0055] Optionally, if the deviation degree of the burner front main air pressure from the average value is greater than 3%, the air intake and the fuel gas intake of the burner are increased or decreased, comprising:

[0056] if the burner front main air pressure is greater than the average value and the deviation degree is greater than 3%, the air intake and the fuel gas intake of the burner are decreased;

[0057] if the burner front main air pressure is less than the average value and the deviation degree is greater than 3%, the air intake and the fuel gas intake of the burner are increased.

[0058] Optionally, the dynamically adjusting the burner front main air valve according to the carbon monoxide detection value and the residual oxygen detection value comprises:

[0059] adjusting the burner front main air valve so that the residual oxygen detection value of each zone of the non-oxidizing furnace is ≤10 ppm, the carbon monoxide detection value of each zone of the non-oxidizing furnace is ≥2000 ppm, the residual oxygen detection value of the preheating furnace is ≤1%, and the carbon monoxide detection value of the preheating furnace is ≤100 ppm.

[0060] Optionally, the dynamically adjusting the burner front main air valve according to the carbon monoxide detection value and the residual oxygen detection value comprises:

[0061] when the residual oxygen at a certain point in the non-oxidizing furnace is higher than the standard value, the burner with a bluish flame or the burner with a greater deviation degree in the balance test in step S201 is adjusted preferentially, and the residual oxygen and the carbon monoxide content of the preheating furnace are controlled by supplementing air.

[0062] Optionally, the standard value is 10 ppm.

[0063] Optionally, the control dew point value is not more than 20℃, including:

[0064] Increase the flow of the atmosphere in the furnace and accelerate the discharge of the wet atmosphere in the non-oxidizing furnace.

[0065] Optionally, the method for increasing the flow of the atmosphere in the furnace and accelerating the discharge of the wet atmosphere in the non-oxidizing furnace includes:

[0066] Increasing the amount of protective gas introduced at the outlet of the annealing furnace and the height of the isolation baffle at the furnace throat to improve the flow and accelerate the discharge of the wet atmosphere.

[0067] Optionally, the method further includes:

[0068] In the step S201, the air and coal gas flow of each furnace temperature control zone of the non-oxidizing furnace is set under the condition that the burner load is 80%, the pressure before the burner is measured under this condition through the differential pressure table, the air pressure deviation is adjusted through the scaled hand valve before the burner, and if the air pressure deviation is large, the pipeline needs to be disassembled to confirm whether there is a blockage.

[0069] Optionally, the air and coal gas flow of each furnace temperature control zone of the non-oxidizing furnace is set to be between 100 and 300 cubic meters; and the large air pressure deviation indicates that the air pressure deviation is greater than 7%.

[0070] By configuring the CO and residual oxygen analyzers for real-time detection in the furnace and the dew point analyzer for measuring the humidity in the furnace, the burners in the multiple furnace temperature control zones of the non-oxidizing furnace are balanced tested, the main air valve before the burner is dynamically adjusted according to the carbon monoxide detection value and the residual oxygen detection value, the dew point value is controlled to be not more than 20℃, and the oxidation defects generated during the strip steel open flame heating can be effectively eliminated to improve the product quality under the premise of ensuring that the heating efficiency is not reduced.

[0071] According to the non-oxidation control method for open flame heating of the annealing furnace provided in the above embodiment, the embodiment of the present application provides an open flame burner, which is controlled by the above-mentioned non-oxidation control method for open flame heating of the annealing furnace. As shown in Figure 2 , the open flame burner includes a fuel gas inlet structure 1, a combustion air inlet structure 2, and a combustion structure 3, wherein the fuel gas inlet structure 1 is detachably connected with the combustion air inlet structure 2, the combustion air inlet structure 2 is detachably connected with the combustion structure 3, and an inlet channel 4 is arranged to communicate the fuel gas inlet structure 1, the combustion air inlet structure 2, and the combustion structure 3.

[0072] The inlet amount of the fuel gas inlet structure, the combustion air inlet structure, and the combustion structure is controlled and adjusted by the above-mentioned method to control the combustion of the open flame burner. The specific control mode is as follows Figure 3shown.

[0073] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been described in detail in order not to obscure the understanding of this description.

[0074] Similarly, it is to be understood that the phraseology or terminology employed herein, and not otherwise specifically set forth in this specification, is for the purpose of description only and not of limitation. Rather, the disclosed aspects will be understood to apply to any apparatus, device, system or method featuring the functionality specified in this specification, and the terminology used can include the words "comprising", "having", "containing", "including", "carrying", "housing" or variants thereof to mean "including, but not limited to", or "comprising, but not limited to" or "having, but not limited to", or "including the recited elements but not others". Furthermore, the above description has been presented for the purpose of illustration and description only. It is not intended to be exhaustive or to limit the application to the precise form disclosed. Many modifications and variations are possible in light of the above teachings. It is intended that the disclosed aspects be construed in accordance with the principles and examples disclosed herein.

[0075] Those skilled in the art will appreciate that the modules in the apparatuses in the embodiments can be adapted and placed in one or more apparatuses other than the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and further can be divided into more sub-modules or sub-units or sub-components. Any combination of all the features disclosed in the specification (including the accompanying claims, abstract and drawings), and any method or apparatus otherwise disclosed in the specification, can be used in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless explicitly stated otherwise, each feature disclosed in the specification (including the accompanying claims, abstract and drawings) can be replaced by alternative features that serve the same, equivalent or similar purpose.

[0076] Furthermore, those skilled in the art will appreciate that different embodiments of the application can have different features and advantages, and no one feature or advantage is necessary to every implementation of the application. Features and advantages of the application are evident from the writings herein, and combinations of features and / or method steps in the above detailed descriptions are only meant to be illustrative and not limiting. Thus, it is intended that the scope of the application should not be limited by any of the above described embodiments, but should be given the broadest interpretation available under the law.

[0077] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of both hardware and software, and any combination thereof. In a unitary claim, several devices or means can be listed, comprising means which can be implemented by one and the same hardware item. The use of the word "a" or "an" does not exclude the presence of a plurality of such elements, nor does it imply that a single element is to be used.

Claims

1. An oxidation-free control method for open flame heating of an annealing furnace, characterized by, The control method comprises the following steps: S101: balance test is performed on the burners in the multiple temperature control zones of the non-oxidizing furnace; S102: the main air valve before the burner is dynamically adjusted according to the carbon monoxide detection value and the residual oxygen detection value; S103: the dew point value is controlled to be no more than 20 DEG C; The balance test on the burners in the multiple temperature control zones of the non-oxidizing furnace comprises: The main air pressure before the burners in the temperature control zones is obtained; the multiple temperature control zones correspond to multiple main air pressures before the burners; The average value of the multiple main air pressures before the burners is obtained; If the deviation degree of the main air pressure before the burner from the average value is greater than 3%, the air intake and the fuel gas intake of the burner are increased or decreased; The deviation degree of the main air pressure before the burner from the average value is equal to the absolute value of the difference between the main air pressure before the burner and the average value divided by the average value; In the step S101, the air-fuel gas flow of each temperature control zone of the non-oxidizing furnace is set when the load of the burner is 80%, and the pressure before the burner is measured by a differential pressure table under this working condition.

2. The method of claim 1, wherein, If the deviation degree of the main air pressure before the burner from the average value is greater than 3%, the air intake and the fuel gas intake of the burner are increased or decreased, comprising: If the main air pressure before the burner is greater than the average value and the deviation degree is greater than 3%, the air intake and the fuel gas intake of the burner are decreased; If the main air pressure before the burner is less than the average value and the deviation degree is greater than 3%, the air intake and the fuel gas intake of the burner are increased.

3. The method of claim 1, wherein, The dynamic adjustment of the main air valve before the burner according to the carbon monoxide detection value and the residual oxygen detection value comprises: The main air valve before the burner is adjusted so that the residual oxygen detection value of each zone of the non-oxidizing furnace is less than or equal to 10 ppm, the carbon monoxide detection value of each zone of the non-oxidizing furnace is greater than or equal to 2000 ppm, the residual oxygen detection value of the preheating furnace is less than or equal to 1%, and the carbon monoxide detection value of the preheating furnace is less than or equal to 100 ppm.

4. The method of claim 1, wherein, The dynamic adjustment of the main air valve before the burner according to the carbon monoxide detection value and the residual oxygen detection value comprises: When the residual oxygen at a certain point in the non-oxidizing furnace is higher than the standard value, the burner with a blue flame or the burner with a greater deviation degree in the balance test in the step S101 is preferentially adjusted, and the residual oxygen and the carbon monoxide content of the preheating furnace are controlled by supplementing air.

5. The method of claim 4, wherein, The standard value is 10 ppm.

6. The method of claim 1, wherein, The dew point value is controlled to be no more than 20 DEG C, comprising: The flowability of the atmosphere in the furnace is improved, and the wet atmosphere in the non-oxidizing furnace is discharged faster.

7. The method of claim 6, wherein, The flowability of the atmosphere in the furnace is improved, and the wet atmosphere in the non-oxidizing furnace is discharged faster, comprising: The amount of protective gas introduced into the outlet of the annealing furnace and the furnace throat is increased, and the height of the isolation baffle of the furnace throat is increased to improve the flowability and accelerate the discharge of the wet atmosphere.

8. The method of claim 1, wherein, The method further comprises: The air pressure deviation is adjusted by the hand valve before the burner with a scale, and if the air pressure deviation is large, the pipeline needs to be disassembled to confirm whether there is a blockage.

9. The method of claim 8, wherein, The air-fuel gas flow of each temperature control zone of the non-oxidizing furnace is set to be between 100 and 300 cubic meters; and a large air pressure deviation indicates that the air pressure deviation degree is greater than 7%.

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