A method for controlling the temperature of a heating furnace

Abstract

The present invention discloses a method for controlling the temperature of a heating furnace, which relates to the technical field of steel rolling. The air-fuel ratio, the air excess coefficient and the limit value are obtained; the temperature difference between the temperature in the furnace and the preset temperature is obtained; if the temperature difference is negative, the adjustment range of the actual gas flow is calculated according to the standard gas flow, the air-fuel ratio, the air excess coefficient and the limit value; if the temperature difference is positive, the adjustment range of the actual air flow is calculated according to the standard air flow, the air-fuel ratio, the air excess coefficient and the limit value. Compared with the prior art, since the method for controlling the temperature of the heating furnace provided by the present invention adopts the step of adjusting the actual air flow or the actual gas flow according to the positive or negative of the temperature difference, it can ensure that the ratio of gas and air in the heating furnace is always in a reasonable state, so as to ensure sufficient combustion, save energy and reduce emissions, and improve production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of steel rolling, and more specifically, to a method for controlling the temperature of a heating furnace. Background Art

[0002] At present, the iron and steel industry is an important basic industry of the national economy, and it is also a major energy consumer and carbon emitter. The energy consumption accounts for 11% of the national energy consumption, and the carbon emissions account for about 15% of the total national carbon emissions. Energy conservation and emission reduction are one of the important driving forces for the sustainable growth of the benefits of iron and steel enterprises. In iron and steel enterprises, the heating furnace is one of the main energy-consuming equipment. However, the ratio of gas to air in the current heating furnace is often in an unreasonable state, resulting in incomplete combustion, generating a large amount of waste gas, causing environmental pollution, wasting energy, and affecting production efficiency.

[0003] In view of this, it is particularly important to design a method for controlling the temperature of a heating furnace that can save energy and reduce emissions, especially in steel rolling production. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for controlling the temperature of a heating furnace, which can ensure that the ratio of gas to air in the heating furnace is always in a reasonable state, so as to ensure complete combustion, save energy and reduce emissions, and improve production efficiency.

[0005] The present invention is implemented by the following technical solutions.

[0006] A method for controlling the temperature of a heating furnace includes: obtaining the air-fuel ratio, the air excess coefficient, and the limit value; obtaining the temperature difference between the temperature inside the furnace and the preset temperature; if the temperature difference is negative, calculating the adjustment range of the actual gas flow according to the standard gas flow, the air-fuel ratio, the air excess coefficient, and the limit value; if the temperature difference is positive, calculating the adjustment range of the actual air flow according to the standard air flow, the air-fuel ratio, the air excess coefficient, and the limit value.

[0007] Optionally, the step of obtaining the air-fuel ratio, the air excess coefficient, and the limit value includes: inferring the air-fuel ratio according to the composition of the high-coke mixed gas; calculating the air excess coefficient according to the actual air consumption and the theoretical air consumption; setting the limit value according to the temperature fluctuation requirement.

[0008] Optionally, the step of calculating the air excess coefficient according to the actual air consumption and the theoretical air consumption includes: dividing the actual air consumption by the theoretical air consumption to obtain the air excess coefficient.

[0009] Optionally, in the step of setting the limit value according to the temperature fluctuation requirement, the range of the limit value is 3% to 8%.

[0010] Optionally, the limit value is 5%.

[0011] Optionally, the step of obtaining the temperature difference between the furnace temperature and the preset temperature includes: measuring the furnace temperature in real time; subtracting the preset temperature from the furnace temperature to obtain the temperature difference.

[0012] Optionally, if the temperature difference is negative, the step of calculating the adjustment range of the actual gas flow rate according to the standard gas flow rate, the air-fuel ratio, the excess air coefficient, and the limit value includes: calculating the adjustment range of the actual gas flow rate according to the first calculation formula, and the first calculation formula is: In the formula, A is the standard gas flow rate, β is the air-fuel ratio, μ is the excess air coefficient, k is the limit value, and B is the actual gas flow rate.

[0013] Optionally, if the temperature difference is positive, the step of calculating the adjustment range of the actual air flow rate according to the standard air flow rate, the air-fuel ratio, the excess air coefficient, and the limit value includes: calculating the adjustment range of the actual air flow rate according to the second calculation formula, and the second calculation formula is: In the formula, C is the standard air flow rate, β is the air-fuel ratio, μ is the excess air coefficient, k is the limit value, and D is the actual air flow rate.

[0014] Optionally, after the step of calculating the adjustment range of the actual gas flow rate according to the standard gas flow rate, the air-fuel ratio, the excess air coefficient, and the limit value, the heating furnace temperature control method further includes: manually or automatically adjusting the gas flow regulator according to the adjustment range of the actual gas flow rate.

[0015] Optionally, after the step of calculating the adjustment range of the actual air flow rate according to the standard air flow rate, the air-fuel ratio, the excess air coefficient, and the limit value, the heating furnace temperature control method further includes: manually or automatically adjusting the air flow regulator according to the adjustment range of the actual air flow rate.

[0016] The heating furnace temperature control method provided by the present invention has the following beneficial effects:

[0017] The heating furnace temperature control method provided by the present invention obtains the air-fuel ratio, the excess air coefficient, and the limit value; obtains the temperature difference between the furnace temperature and the preset temperature; if the temperature difference is negative, calculates the adjustment range of the actual gas flow rate according to the standard gas flow rate, the air-fuel ratio, the excess air coefficient, and the limit value; if the temperature difference is positive, calculates the adjustment range of the actual air flow rate according to the standard air flow rate, the air-fuel ratio, the excess air coefficient, and the limit value. Compared with the prior art, since the heating furnace temperature control method provided by the present invention adopts the step of adjusting the actual air flow rate or the actual gas flow rate according to the positive or negative of the temperature difference, it can ensure that the ratio of gas and air in the heating furnace is always in a reasonable state, thereby ensuring full combustion, saving energy and reducing emissions, and improving production efficiency. Description of the Drawings

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a step block diagram of the heating furnace temperature control method provided by the embodiments of the present invention. Detailed implementation manners

[0020] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0023] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "inner", "outer", "upper", "lower", "horizontal", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, terms such as "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "arrangement", "connection", "installation", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] The following will describe in detail some embodiments of the present invention with reference to the drawings. Without conflict, the features in the following embodiments can be combined with each other.

[0026] Please refer to Figure 1 , an embodiment of the present invention provides a heating furnace temperature control method for regulating the temperature of the heating furnace. It can ensure that the ratio of gas to air in the heating furnace is always in a reasonable state, thereby ensuring full combustion, saving energy and reducing emissions, and improving production efficiency.

[0027] It should be noted that the heating furnace temperature control method is applied to the heating furnace, which is located between the steelmaking continuous casting machine and the rolling mill and plays a connecting role. The heating furnace has the characteristics of flexible heating of cold materials and hot materials and strong adaptability. Specifically, the heating furnace obtains heat through gas combustion, and gas combustion requires oxygen, which comes from the air. Therefore, the heating furnace temperature control method adjusts the gas and air flow rates in the heating furnace to make the ratio of gas to air always in a reasonable state, thereby ensuring full combustion, saving energy and reducing emissions, and improving the production efficiency of the heating furnace.

[0028] The heating furnace temperature control method includes the following steps:

[0029] Step S110: Obtain the air-fuel ratio, the air excess coefficient, and the limit value.

[0030] Specifically, step S110 includes three steps, which are respectively:

[0031] Step S111: Estimate the air-fuel ratio based on the composition of the high-oven mixed gas.

[0032] It should be noted that in step S111, the air-fuel ratio is theoretically estimated using the composition of the high-oven mixed gas. The high-oven ratio is the ratio of the blast furnace gas flow rate to the coke oven gas flow rate. In this embodiment, assuming that the measured high-oven ratio is 7:3, and then according to the gas composition (mainly containing carbon monoxide, hydrogen, and methane) and the mixing situation, the air-fuel ratio can be calculated as 1.77, that is, the ratio of the theoretical air requirement to the theoretical gas mixing amount is 1.77. That is to say, when the volume ratio of air to gas is 1.77, the gas can burn fully.

[0033] Step S112: Calculate the air excess coefficient based on the actual air consumption and the theoretical air consumption.

[0034] It should be noted that in Step S112, due to the influence of various factors on the actual on-site situation, the actual air consumption and the theoretical air consumption required for burning a certain amount of gas are different. Therefore, it is necessary to calculate the air excess coefficient based on the actual air consumption and the theoretical air consumption required for burning a certain amount of gas. In this embodiment, the actual air consumption is divided by the theoretical air consumption to obtain an air excess coefficient of 1.05, that is, the ratio of the actual air consumption to the theoretical air consumption is 1.05.

[0035] Step S113: Set the limit value according to the temperature fluctuation requirement.

[0036] It should be noted that in Step S113, the temperature fluctuation requirement is obtained according to the type and process standard of the rolled steel, and then the limit value is set according to the temperature fluctuation requirement. Specifically, the range of the limit value is 3% to 8%. A reasonable limit value can ensure that the temperature fluctuation in the heating furnace is within a certain range, thereby ensuring the stability and reliability of the rolled steel process.

[0037] In this embodiment, the limit value is 5%, but it is not limited thereto. In other embodiments, the limit value can be 3% to 4%, or 6% to 8%. The size of the limit value is not specifically limited.

[0038] Step S120: Obtain the temperature difference between the temperature in the furnace and the preset temperature.

[0039] Specifically, Step S120 includes two steps, which are respectively:

[0040] Step S121: Measure the temperature in the furnace in real time.

[0041] It should be noted that in Step S121, the temperature sensor is used to measure the temperature in the heating furnace in real time, so as to make appropriate adjustments to the gas flow rate and air flow rate in a timely manner through subsequent steps when the temperature in the furnace changes, thereby ensuring that the gas combustion is always in a sufficient state.

[0042] Step S122: Subtract the preset temperature from the temperature in the furnace to obtain the temperature difference.

[0043] It should be noted that in step S122, the preset temperature is set according to the type and process standard of steel rolling. The temperature difference that changes in real time is obtained by subtracting the preset temperature from the temperature in the furnace measured in real time. Specifically, if the temperature difference is negative, it means that the temperature in the furnace is lower than the preset temperature, indicating that the gas combustion degree of the heating furnace is insufficient and the temperature does not reach the requirement. At this time, it is necessary to increase the gas flow rate and maintain the air flow rate to raise the temperature of the heating furnace; if the temperature difference is positive, it means that the temperature in the furnace is higher than the preset temperature, indicating that the gas combustion in the heating furnace is excessive and the local or all temperatures in the heating furnace exceed the requirement. At this time, it is necessary to increase the air flow rate and maintain the gas flow rate to dilute the gas flow rate and achieve the local or all cooling of the heating furnace.

[0044] Step S130: If the temperature difference is negative, calculate the adjustment range of the actual gas flow rate according to the standard gas flow rate, air-fuel ratio, air excess coefficient and limit value.

[0045] It should be noted that in step S130, the adjustment range of the actual gas flow rate is calculated according to the first calculation formula for facilitating the subsequent adjustment of the actual gas flow rate. The first calculation formula is:

[0046]

[0047] In the formula, A is the standard gas flow rate, that is, the actual on-site required gas flow rate under the standard condition (the ratio of the volume of combustible gas to the volume of air is 1:1), β is the air-fuel ratio, that is, the air-fuel ratio of the actually used gas after being discounted relative to the standard gas, μ is the air excess coefficient, k is the limit value, and B is the actual gas flow rate.

[0048] Step S140: Manually or automatically adjust the gas flow regulator according to the adjustment range of the actual gas flow rate.

[0049] It should be noted that in step S140, the gas flow regulator is adjusted manually or automatically to increase or decrease the opening degree of the regulating valve of the gas flow regulator, so that the actual gas flow rate entering the heating furnace through the gas flow regulator is within the adjustment range, and further ensure that the ratio of gas and air in the heating furnace is always in a reasonable state and ensure full combustion.

[0050] Step S150: If the temperature difference is positive, calculate the adjustment range of the actual air flow rate according to the standard air flow rate, air-fuel ratio, air excess coefficient and limit value.

[0051] It should be noted that in step S150, the adjustment range of the actual air flow rate is calculated according to the second calculation formula for facilitating the subsequent adjustment of the actual air flow rate to dilute the gas flow rate. The second calculation formula is:

[0052]

[0053] In the formula, C is the standard air flow rate, which is the actual on-site required air flow rate under standard conditions (the ratio of the volume of combustible gas to the volume of air is 1:1), β is the air-fuel ratio, which is the air-fuel ratio after the actual used gas is discounted relative to the standard gas, μ is the excess air coefficient, k is the limit value, and D is the actual air flow rate.

[0054] Step S160: Manually or automatically adjust the air flow regulator according to the adjustment range of the actual air flow rate.

[0055] It should be noted that in step S160, the air flow regulator is adjusted manually or automatically to increase or decrease the opening degree of the regulating valve of the air flow regulator, so that the actual air flow rate entering the heating furnace through the air flow regulator is within the adjustment range, diluting the gas flow rate, and further ensuring that the ratio of gas to air in the heating furnace is always in a reasonable state and ensuring full combustion.

[0056] It is worth noting that since the temperature difference is constantly changing, the temperature difference may continuously switch between positive and negative values. At this time, steps S130 and S150 need to be alternately executed, and steps S140 and S160 will also be alternately executed. Specifically, if the initial temperature difference is negative, after executing steps S130 and S140, the actual gas flow rate is increased and the furnace temperature rises. When the furnace temperature is greater than the preset temperature, the temperature difference becomes positive, and at this time, steps S150 and S160 are executed. If the initial temperature difference is positive, after executing steps S150 and S160, the actual air flow rate is increased to dilute the gas flow rate, so that the furnace temperature decreases. When the furnace temperature is less than the preset temperature, the temperature difference becomes negative, and at this time, steps S130 and S140 are executed.

[0057] In this embodiment, the heating furnace temperature control method makes the furnace temperature match the preset temperature by dynamically adjusting the actual gas flow rate or the actual air flow rate, so as to effectively improve the dynamic characteristics of the heating furnace combustion control system. And the heating furnace temperature control method limits the change range of the gas flow rate and the air flow rate in the transition state, reduces the adverse effects caused by the time factor difference between the gas control loop and the air control loop, ensures that a reasonable gas-to-air ratio can still be achieved when the heat load suddenly increases or decreases, and keeps the combustion in the best state under any circumstances, so as to achieve the purpose of saving energy, protecting the environment and improving production efficiency.

[0058] The method for controlling the temperature of a heating furnace provided by an embodiment of the present invention includes obtaining the air-fuel ratio, the air excess coefficient, and the limit value; obtaining the temperature difference between the furnace temperature and the preset temperature; if the temperature difference is negative, calculating the adjustment range of the actual gas flow based on the standard gas flow, the air-fuel ratio, the air excess coefficient, and the limit value; if the temperature difference is positive, calculating the adjustment range of the actual air flow based on the standard air flow, the air-fuel ratio, the air excess coefficient, and the limit value. Compared with the prior art, since the method for controlling the temperature of the heating furnace provided by the present invention adopts the step of adjusting the actual air flow or the actual gas flow according to the positive or negative of the temperature difference, it can ensure that the ratio of gas and air in the heating furnace is always in a reasonable state, thus ensuring full combustion, saving energy and reducing emissions, and improving production efficiency.

[0059] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for controlling the temperature of a heating furnace, characterized in that, Including: Obtain the air-fuel ratio, the air excess coefficient, and the limit value; Obtain the temperature difference between the furnace temperature and the preset temperature; If the temperature difference is negative, calculate the adjustment range of the actual gas flow according to the standard gas flow, the air-fuel ratio, the air excess coefficient, and the limit value, including: calculating the adjustment range of the actual gas flow according to the first calculation formula, and the first calculation formula is: In the formula, A is the standard gas flow, β is the air-fuel ratio, μ is the air excess coefficient, k is the limit value, and B is the actual gas flow; If the temperature difference is positive, calculate the adjustment range of the actual air flow according to the standard air flow, the air-fuel ratio, the air excess coefficient, and the limit value, including: calculating the adjustment range of the actual air flow according to the second calculation formula, and the second calculation formula is: In the formula, C is the standard air flow, β is the air-fuel ratio, μ is the air excess coefficient, k is the limit value, and D is the actual air flow.

2. The method for controlling the temperature of a heating furnace according to claim 1, characterized in that, The steps of obtaining the air-fuel ratio, the air excess coefficient, and the limit value include: Speculate the air-fuel ratio according to the composition of the high-coke mixed gas; Calculate the air excess coefficient according to the actual air consumption and the theoretical air consumption; Set the limit value according to the temperature fluctuation requirement.

3. The method for controlling the temperature of a heating furnace according to claim 2, characterized in that, The steps of calculating the air excess coefficient according to the actual air consumption and the theoretical air consumption include: Divide the actual air consumption by the theoretical air consumption to obtain the air excess coefficient.

4. The method for controlling the temperature of a heating furnace according to claim 2, characterized in that, In the step of setting the limit value according to the temperature fluctuation requirement, the range of the limit value is 3% to 8%.

5. The method for controlling the temperature of a heating furnace according to claim 4, characterized in that, The limit value is 5%.

6. The method for controlling the temperature of a heating furnace according to claim 1, wherein The steps of obtaining the temperature difference between the furnace temperature and the preset temperature include: Measure the furnace temperature in real time; Subtract the preset temperature from the furnace temperature to obtain the temperature difference.

7. The method for controlling the temperature of a heating furnace according to claim 1, characterized in that After the step of calculating the adjustment range of the actual gas flow according to the standard gas flow, the air-fuel ratio, the air excess coefficient, and the limit value, the heating furnace temperature control method further includes: Manually or automatically adjust the gas flow regulator according to the adjustment range of the actual gas flow.

8. The method for controlling the temperature of a heating furnace according to claim 1, characterized in that, After the step of calculating the adjustment range of the actual air flow according to the standard air flow, the air-fuel ratio, the air excess coefficient, and the limit value, the heating furnace temperature control method further includes: Manually or automatically adjust the air flow regulator according to the adjustment range of the actual air flow.

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