Asymmetric characteristic dynamic control method for glass melting furnace and its flue gas pipe network

Abstract

The application glass melting furnace and its flue gas pipe network asymmetric characteristic dynamic control method belong to the glass melting furnace control technology, the external air entering amount calculation mathematical model and the air excess coefficient calculation mathematical model are developed to carry out dynamic control on the external air entering amount and the air excess coefficient, the entering amount of the external air is calculated through the argon content of the flue gas analysis detection, then the air inlet valve opening is adjusted according to the difference between the set value and the calculated value, so that the external air entering amount is always controlled in the set value range; the air flow and the gas flow are adjusted according to the oxygen content and the carbon monoxide content of the flue gas analysis detection, so that the air excess coefficient is controlled, so that the air excess coefficient is always controlled in the set value range; the multiple energy saving and emission reduction effects of improving the combustion efficiency, reducing the total amount of generated flue gas, improving the energy saving amount of the induced draft fan, reducing the NOx pollution emission amount and realizing the full automatic control are obtained, and the application can be widely applied to the glass melting furnace systems of new construction, expansion and transformation.

Description

Technical Field

[0001] This invention pertains to glass melting furnace control technology, specifically the control technology for the amount of external air entering the glass melting furnace and the control technology for the excess air coefficient. It does not involve the liquid level system of the glass melting furnace. This invention does not involve the selection of control systems, control equipment, and instruments. Background Technology

[0002] In the glass industry, energy consumption for glass melting accounts for 30% to 75% of the total energy consumption of the entire industry. Depending on the type of glass, energy costs account for 10% to 25% of the total cost. Therefore, improving the thermal efficiency of glass melting furnaces has an extremely important impact on reducing glass manufacturing costs. Compared with the international advanced level, the thermal efficiency of glass melting furnaces in my country is relatively low, generally only 20% to 25%. Therefore, the glass industry has great potential for energy saving.

[0003] Glass melting furnaces are also major sources of gaseous pollution, with NOx emissions being particularly serious, making them a key target for remediation.

[0004] Existing technologies use the detection of oxygen and carbon monoxide content in flue gas to calculate and estimate the excess air coefficient to guide operations; however, due to the lack of theoretical support and proper control strategies, dynamic control of the excess air coefficient in glass melting furnaces remains a blank in practice.

[0005] In terms of technology, even at the internationally advanced level, there is still considerable room for improvement in the control level of glass melting furnaces. In particular, there are still technical bottlenecks. Among them, the dynamic controllability of the excess air coefficient of the glass melting furnace system and the control of the amount of external air entering the glass melting furnace have not been solved for a long time. As a result, it is difficult to improve the thermal efficiency of the glass melting furnace, and problems such as high fuel consumption, high heat loss of the glass melting furnace, large amount of pollutant emissions, and limited energy saving of fans still exist.

[0006] Due to the lack of fundamental theory for dynamically controlling the excess air coefficient and the amount of external air entering the glass melting furnace, existing technologies are fundamentally unable to meet the needs of deep energy conservation and emission reduction in glass melting furnaces. Breakthroughs in theoretical research and applied technologies are urgently needed.

[0007] No publicly available publications, documents, or materials have been found regarding dynamic control methods for the asymmetric characteristics of glass melting furnaces and their flue gas pipelines, which involve dynamic control of the excess air coefficient and the amount of external air entering the furnace. Summary of the Invention

[0008] The purpose of this invention is to seek breakthroughs in the technical bottlenecks that restrict the existing technology based on the characteristics of the glass melting furnace's operating conditions, and to research and develop a dynamic control method for the asymmetric characteristics of the glass melting furnace and its flue gas pipeline network that is adapted to the operating conditions of the glass melting furnace, so as to achieve the effect of deep energy saving and emission reduction in the glass melting furnace.

[0009] The key point of this invention is to address the problems existing in current technologies, break through their foundations and frameworks, and, based on the operating characteristics of glass melting furnaces and the physical properties of their flue gas pipelines, innovatively establish an asymmetric system theory for glass melting furnaces. Mathematical models for calculating the amount of external air entering the glass melting furnace and the excess air coefficient are developed. A dynamic control method for the amount of external air entering the glass melting furnace and the excess air coefficient based on this asymmetric system theory is also developed. The amount of external air entering the glass melting furnace is calculated using argon content detected by flue gas analysis. Then, based on the difference between the set value and the calculated value of the external air entering the glass melting furnace, the opening of the induced draft fan inlet valve is adjusted, thus controlling the external air entering the glass melting furnace. The closed-loop dynamic adjustment system for air intake ensures that the amount of external air entering the glass melting furnace is always controlled within a set range. By adjusting the airflow and fuel flow based on the oxygen and carbon monoxide content detected in the flue gas, the excess air coefficient of the glass melting furnace is controlled, forming a closed-loop dynamic adjustment system for the excess air coefficient. This ensures that the excess air coefficient is always kept within the set range. Effective control of the external air intake and the excess air coefficient results in multiple energy-saving and emission-reduction effects, including improved combustion efficiency, reduced total flue gas generation, increased energy savings for the induced draft fan, reduced NOx emissions, fully automated control of the glass melting furnace, reduced operator workload, and increased production efficiency. This leads to multiple benefits of energy conservation, emission reduction, increased production, and guaranteed quality. Attached Figure Description

[0010] Figure 1 This is a block diagram of a technical solution for dynamic control of the asymmetric characteristics of glass melting furnaces and their flue gas pipelines. Figure 1 1 is the HMI (Human Interface Management) station for the glass melting furnace control system; 2 is the setpoint for external air intake; 3 is the adjustment of the induced draft fan inlet valve opening; 4 is the mathematical model for calculating the external air intake of the glass melting furnace; 5 is the total Ar content in the flue gas duct; 6 is the total flue gas flow rate in the flue gas duct; 7 is the actual value of the combustion air volume; 8 is the actual value of the compressed air volume in the spray gun; 9 is the input of the proportion coefficient k; 10 is the mathematical model for calculating the excess air coefficient of the glass melting furnace; 11 is the setpoint for the excess air coefficient; and 12 is the total O2 quantity in the flue gas duct. 13 is the air regulating valve i adjustment, 14 is the air regulating valve n adjustment, 15 is the air-fuel ratio, 16 is the hot spot temperature setpoint, 17 is the actual hot spot temperature, 18 is the gas regulating valve i adjustment, 19 is the gas regulating valve n adjustment, 20 is the glass melting furnace CO setpoint, 21 is the actual CO value in the main flue, 22 is the melting section end pressure setpoint, 23 is the induced draft fan airflow adjustment, 24 is the actual melting section end pressure value, 25 is the glass melting furnace temperature i detection, 26 is the glass melting furnace temperature n detection, 27 is the glass melting furnace pressure i detection, 28 is the glass melting furnace pressure n detection, and 29 is the glass melting furnace on-site process equipment.

[0011] Figure 2 This is a control system configuration diagram of a dynamic control method for the asymmetric characteristics of a glass melting furnace and its flue gas pipeline network. Figure 2 1 is the main process control system of the glass melting furnace; 2 is the HMI operator station of the glass melting furnace control system; 3 is the external air intake setpoint; 4 is the excess air coefficient setpoint; 5 is the CO setpoint of the glass melting furnace; 6 is the end pressure setpoint of the melting section; 7 is the hot spot temperature setpoint; 8 is the air-fuel ratio setpoint input; 9 is the proportion coefficient k input; 10 is the dynamic controller of the asymmetric system of the glass melting furnace and its flue gas pipeline; 11 is the Ar content detector in the total flue gas duct; 12 is the O2 content detector in the total flue gas duct; 13 is the CO content detector in the total flue gas duct; 14 is the flue gas flow rate detector in the total flue gas duct; and 15 is the combustion air. The data includes: actual air volume value, compressed air volume detection for the spray gun, pressure detection at the end of the melting section, hot spot temperature detection, induced draft fan inlet valve opening adjustment, induced draft fan air volume adjustment, air regulating valve i adjustment, air regulating valve n adjustment, gas regulating valve i adjustment, gas regulating valve n adjustment, glass melting furnace temperature i detection, glass melting furnace temperature n detection, glass melting furnace pressure i detection, glass melting furnace pressure n detection, 29 on-site process equipment information, and on-site process equipment for the glass melting furnace.

[0012] Figure 1 The technical solution block diagram is constructed based on the general characteristics of glass melting furnaces. In reality, there are many types of glass melting furnaces, including various types with different process parameters and equipment layouts. To avoid tedious descriptions and confusion, this technical solution considers the general situation with common characteristics, without distinguishing the details of the specific glass melting furnace process and equipment composition. However, the control principles, conclusions, and beneficial effects described in this paper are applicable to glass melting furnaces. Detailed Implementation

[0013] Basic terms and definitions: The excess air coefficient in a glass melting furnace system, also known as the excess air coefficient or excess air factor, is defined as "the ratio of the actual air requirement to the theoretical air requirement during fuel combustion", and is represented by the letter α.

[0014] By definition, the excess air coefficient refers to the result obtained by the glass melting furnace combustion system at a set air-fuel ratio, that is, the combustion effect of combustion air and fuel under that air-fuel ratio condition. This combustion effect does not include the effect of combustion caused by the amount of external air entering the glass melting furnace. Although the amount of external air entering the glass melting furnace may result in partial or complete combustion, compared with a combustion system based on the air-fuel ratio, the external air entering the glass melting furnace is cold air, which will cause heat loss and thus has a negative impact, which is not conducive to improving the thermal efficiency of the glass melting furnace. The oxidizing atmosphere caused by excess air will also increase NOx emissions. The excess air coefficient and the amount of external air entering the glass melting furnace have different meanings. Therefore, the oxygen content detected in the main flue gas network does not represent the excess air coefficient or the amount of external air entering the glass melting furnace; this oxygen content is a mixture of the two.

[0015] The existing method for controlling the excess air coefficient in glass melting furnaces is to calculate and estimate the excess air coefficient value based on the detected oxygen and carbon monoxide content in the flue gas. Different types of glass melting furnaces have recommended ranges or limits for the excess air coefficient to guide operators in manually adjusting the excess air coefficient. However, this method is actually not advisable.

[0016] The reason is: First, there are problems with the current understanding of the excess air coefficient in glass melting furnaces. According to the definition of the excess air coefficient, the so-called excess air coefficient obtained by detecting the oxygen content in flue gas using current technology is not a true excess air coefficient because it includes the oxygen content of the air entering the glass melting furnace from outside. The true excess air coefficient refers to the result of combustion after setting the air-fuel ratio, and does not include the oxygen content of the air entering from outside. This concept is supported by the new version of the Boiler Air Pollutant Emission Standard GB13271-2014. The new national standard uses the term "baseline oxygen content" for pollutant emission concentration, instead of the "excess air coefficient" in the original national standard GB13271-2001. That is, the oxygen content detected in the flue gas is not equal to the "excess air coefficient," correcting the previous ambiguous concept. Previously, calculating the "excess air coefficient" based on the oxygen content detected in the flue gas also lacked theoretical basis, and current technology did not have a method to accurately calculate the "excess air coefficient." Therefore, the current national standard's use of the term "baseline oxygen content" for pollutant emission concentration is a wise move to avoid misleading the public.

[0017] Secondly, misunderstandings make it difficult to implement existing technologies. Because there is no theoretical basis for specific guidance, operators can only rely on experience and make manual adjustments based on the recommended range or limit of the excess air coefficient. It is difficult to obtain the desired results. In fact, the dynamic control function of the excess air coefficient is completely lacking in the current glass melting furnace system control.

[0018] Dynamic control of the excess air coefficient in glass melting furnaces is a typical and long-standing industrial control problem. It is a common issue for glass melting furnaces with similar operating conditions and is considered a complex industrial system control problem, making it highly representative. To date, existing technologies have not found a method for dynamic control of the excess air coefficient in glass melting furnaces, and remain at the level of manual adjustment or a combination of automatic and manual intervention control methods where the control strategy is not entirely correct.

[0019] The oxygen content measured in flue gas does not represent the excess air coefficient α. Using oxygen content to represent or calculate the excess air coefficient for combustion control will produce erroneous results. The following is a qualitative analysis of the hazards that existing control strategies may cause.

[0020] Let the oxygen content detected in the flue gas be A. Since the oxygen in the flue gas consists of two parts: one is the residual oxygen caused by an improper air-fuel ratio, denoted as B; the other is the oxygen brought in by external air entering the glass melting furnace, denoted as C. B has three possible cases: α > 1, α = 1, and α < 1. C only has one possible case: based on the fundamental characteristics of a glass melting furnace, it's impossible for no external air to enter at all. Therefore, there is no case where oxygen = zero; only the case where oxygen > 0 exists. We consider that C may partially burn, completely burn, or not burn with CO in the flue gas. Combustion and C will react with nitrogen under high temperature conditions to produce NOx. Therefore, let D be the part of oxygen lost through combustion and reaction. Based on these conditions, the oxygen measured in the flue gas is composed of two parts of oxygen, B and C. There are three possible combinations to form A. The first case is when α > 1, B and C mix, so A = B + CD. The second case is when α = 1, that is, when the air-fuel ratio is 1, B is zero, so A = CD. The third case is when α < 1, that is, the remaining oxygen of B is zero, but there is remaining CO, so A = CD.

[0021] The existing technology controls based on A. In the first case, the operator adjusts the combustion air to decrease or increase the gas ratio, thus reducing B. However, the control is actually based on A. Since A > B, the result of the control will be α < 1. In the second case, since the air-fuel ratio is 1, the operator adjusts the combustion air to decrease or increase the gas ratio, and the result of the control will inevitably be α < 1. In the third case, the result of the control is the same as the second case, which will also be α < 1. The difference is that the combustion situation is even worse.

[0022] Based on the above analysis, according to the existing technology's control strategy based on A, the control result will always be α < 1 regardless of the situation. Therefore, compared with the state before control, combustion deterioration is inevitable, resulting in increased fuel consumption, decreased furnace thermal efficiency, and increased NOx emissions. Thus, the existing technology's control strategy is not advisable.

[0023] So, how can combustion be optimized and controlled? How can the thermal efficiency of glass melting furnaces be improved? What are the key issues with existing technologies? How can the problems of existing technologies be solved? The present invention will provide theoretical analysis, conclusions, control strategies, and technical solutions below.

[0024] Theoretical Analysis: When technology encounters a bottleneck, there are inevitably fatal obstacles. To overcome this bottleneck, one must have a mindset different from that of existing technologies, break free from the constraints of the existing technological framework, and importantly, re-examine the essence of the controlled object—that is, to overturn the incorrect understanding of the controlled object by existing technologies.

[0025] First, let's analyze the general situation of furnaces and kilns. As the process parameters or production load change, the amount of furnace gas generated in the furnace and kiln also changes. As the production load increases or decreases, the amount of furnace gas also increases or decreases. However, furnaces and kilns have a common characteristic: without external pre-application of control, when the amount of furnace gas increases, the furnace pressure will rise; when the amount of furnace gas decreases, the furnace pressure will not decrease, but will remain at the original state. This phenomenon in furnaces and kilns is formed by the characteristics of the furnace and kiln equipment itself and the characteristics of the flue gas pipeline network. The furnace and kiln equipment is not a very tight closed system and usually operates in a state of slight negative pressure in the furnace. The furnace gas generated in the furnace and kiln is discharged from the flue gas pipeline network under the action of the induced draft fan. When the furnace load increases, the gas flow rate increases, and the furnace pressure rises. The furnace pressure detection and regulation system controls the induced draft fan speed or the opening of the induced draft fan inlet valve to change the flue gas output flow rate and balance the pressure. When the furnace load decreases, the gas flow rate decreases, but the furnace pressure does not change, or does not change significantly. This is because as the gas flow rate gradually decreases, the reduced portion is gradually filled by air entering from outside the furnace and the flue gas generated there, so the furnace pressure remains in equilibrium. In this case, the furnace pressure detection and regulation system does not activate furnace pressure regulation. This phenomenon in the furnace is called an "asymmetric system" process.

[0026] "Asymmetric systems" are highly deceptive and misleading, thus obscuring and deceiving existing technologies. Consider this: existing technologies employ the conventional symmetric control strategy to control asymmetric systems, regulating furnace pressure through a closed-loop system based on furnace pressure detection. This effectively creates a one-sided regulation phenomenon—it only regulates when the gas flow increases, not when it decreases. If the system repeats this cycle of increasing and decreasing gas flow several times, the furnace pressure regulation system will collapse or enter an unstable operating state. This is the long-standing problem of unstable furnace pressure control in furnaces. For furnaces with relatively stable production loads, although the displayed furnace pressure fluctuates within a small range, giving the impression of good control, the oxygen content detected in the flue gas confirms that the furnace pressure is actually under control. Beneath the surface of stable power, the oxygen content of the system has actually deteriorated, indicating that the existing technology is in a state of loss of control over the amount of external air entering the system. At the same time, the increase in oxygen content has misled the existing technology to manually adjust the excess air coefficient, causing the combustion system, which was originally operating stably, to enter a chaotic state. This has affected the temperature control and caused disorder. This is the root cause of the difficulty in stabilizing the furnace temperature system that has been encountered in the furnace for a long time. However, the existing technology has not realized the impact of the "asymmetric system". Instead, it has attributed the difficulty in stabilizing the furnace temperature system to factors such as the instability of the combustion medium pipeline pressure and the changes in the composition of the combustion medium. Therefore, the temperature control strategy adopted is contrary to the objective reality, which has led to the passive situation of the furnace temperature system being difficult to stabilize.

[0027] Glass melting furnaces are also a type of furnace and possess the general characteristics of furnaces. Therefore, the asymmetric characteristics of furnaces also exist in glass melting furnaces, directly affecting the stable control of pressure and temperature. Glass melting furnaces differ from general furnaces in that they operate under more complex conditions, with different processes and equipment characteristics. It should be noted that the statement in glass melting furnace control that the furnace pressure in the melting section must be zero or slightly positive, and cannot be negative, refers to the furnace pressure at the end of the melting section. In reality, the pressure at the feeding end is still in a negative or slightly negative state. In this respect, glass melting furnaces are not fundamentally different from general furnaces. This understanding can be confirmed by the oxygen content detected in the flue gas of glass melting furnaces. Currently, most glass melting furnaces operate under a large excess air coefficient, and most of the oxygen content is due to the influx of external air caused by the negative pressure at the feeding end.

[0028] Technical solutions

[0029] Theoretically speaking, the theory of asymmetric furnace systems, which reveals the physical characteristics of furnaces and their flue gas pipelines, lays the theoretical foundation for realizing dynamic automatic control of pressure and temperature in glass melting furnaces. The next step is to specifically solve the problems that existing technologies have not solved or cannot solve.

[0030] Current technologies have not solved the problem of dynamic automatic control of the excess air coefficient in glass melting furnaces. In particular, they have not recognized the impact of the amount of external air entering the glass melting furnace on the pressure and temperature control of the furnace, let alone how to solve this problem. They are still limited to detecting oxygen content through flue gas analysis, converting it into a so-called excess air coefficient, and then having operators manually adjust the combustion air volume. In reality, since the oxygen content detected by flue gas analysis does not represent the true excess air coefficient, and the so-called optimal excess air coefficient obtained by system tests or simulation calculations is also conducted under incorrect conditions, the excess air coefficient obtained by current technologies and the control strategies adopted have serious technical flaws. Therefore, current technologies cannot achieve dynamic automatic control of the excess air coefficient.

[0031] The key to solving this problem lies in the correct analysis and accurate calculation of the excess air coefficient. The oxygen content detected in the total flue gas is partly due to an improper air-fuel ratio in the combustion system, resulting in an excessively high excess air coefficient and excess oxygen. Another part is the oxygen contained in the air entering the glass melting furnace from outside, after combustion or uncombustion within the furnace and piping. Accurately calculating the oxygen content of each component is the crucial issue this technical solution needs to address. To determine the oxygen content related to the excess air coefficient, we must first calculate the oxygen content of the air entering the glass melting furnace from outside. Then, subtracting the oxygen content of the air entering the glass melting furnace from the oxygen content measured in the total flue gas yields the oxygen content related to the excess air coefficient. To calculate the oxygen content of the air entering the glass melting furnace from outside, we first need to know the amount of air entering the furnace from outside. This leads to the development of dynamic control technology for the amount of air entering the glass melting furnace from outside, representing another significant leap forward compared to existing technologies.

[0032] To control the amount of external air entering the glass melting furnace, it is first necessary to accurately calculate the amount of external air entering. To this end, this invention has developed a mathematical model (1) for calculating the amount of external air entering the furnace: Q air = (Q) w1 × A rw1 - (Q) i1 +Q i2 )×A rb )×100 / 0.934 (1) In the formula: Q i1 Combustion air flow rate, m 3 / s; Q i2 : Compressed air volume of the spray gun, m 3 / s; A rb : Standard argon mole fraction in air, mol% Q w1 Total flue gas flow rate, m 3 / s; A rw1 Argon mole fraction in total flue gas, mol% Q air Air volume entering the glass melting furnace (m) 3 / s; Based on the characteristic that inert gases are difficult to participate in chemical reactions, the amount of external air entering the glass melting furnace is calculated by detecting inert gases in the flue gas, which can ensure the accuracy of the calculation. This technical solution uses argon as the basis for flue gas analysis and calculation, but it is not limited to using argon for different types of glass melting furnaces in actual applications.

[0033] After accurately calculating the amount of external air entering the glass melting furnace using the mathematical model for calculating the amount of external air entering the furnace, the oxygen content can be analyzed and calculated. According to equation (1), equation (2) can be derived as the mathematical model for calculating the oxygen volume flow rate in the amount of external air entering the glass melting furnace.

[0034] O 2e = (Q) w1 × A rw1 - (Q) i1 +Q i2 )×A rb )×20.95 / 0.934 (2) In the formula: O 2e Oxygen volumetric flow rate in the external air intake of a glass melting furnace, in m³ 3 / s; The actual value of oxygen content in the excess air coefficient can be obtained by subtracting the oxygen volume flow rate in the total flue gas from the oxygen volume flow rate in the external air volume flow rate calculated by the mathematical model of formula (2). This value is calculated by the mathematical model of oxygen content calculation in the excess air coefficient of formula (3). O 2a = (Q) w1 ×O 21 -kO 2e ) / Q w1 (3) In the formula: O 2a The actual oxygen content in the excess air coefficient, % O 21 Oxygen mole fraction in total flue gas, mol% k: Proportion coefficient, 0~1; In equation (3), k represents the percentage of oxygen volume remaining when the volume of oxygen entering from the outside reaches the detection point of the main flue, i.e., the proportion of the remaining oxygen volume to the total oxygen volume entering from the outside, referred to as the proportion coefficient, with a value range of 0 to 1; because the oxygen entering from the outside... 2e The possibility of unburned, partially burned, or completely burned is a variable related to the air leakage of the glass melting furnace and its flue gas pipeline network. It cannot be accurately calculated mathematically, so an engineering coefficient method is adopted to solve the problem. The proportion coefficient k is determined by the glass melting furnace process engineer based on the detection statistics of the amount of external air entering the glass melting furnace body and the air leakage of the flue gas pipeline network, and is entered into the HMI operation station.

[0035] Substituting equation (3) into the simplified mathematical model (4) for calculating the excess air coefficient, we obtain equation (5) for calculating the excess air coefficient.

[0036] α = 20.95 / (20.95 - 0) 2a (4) In the formula: α: Excess air coefficient, >0.

[0037] α = 20.95 / (20.95 - (Q)) w1 ×O 21 - kO 2e )÷Q w1 (5) In the formula: α: Excess air coefficient, >0.

[0038] With the mathematical models of equations (1), (2), (3), (4) and (5), the dynamic automatic control problem of glass melting furnace is solved based on the theory of asymmetric furnace systems and the adoption of corresponding control strategies.

[0039] Figure 1 This is a block diagram of a technical solution for dynamic control of the asymmetric characteristics of glass melting furnaces and their flue gas pipelines. Figure 1The HMI operation station (1) of the glass melting furnace control system is the human-machine interface of the dynamic control system of the glass melting furnace and its flue gas pipeline asymmetric system; the external air inlet setpoint (2) is connected to the glass melting furnace control system HMI operation station (1) and the induced draft fan inlet valve opening adjustment (3), and this setpoint is input by the human-machine interface; the induced draft fan inlet valve opening adjustment (3) is connected to the external air inlet setpoint (2), the mathematical model for calculating the external air inlet of the glass melting furnace (4), and the glass melting furnace on-site process equipment (29), and the difference between the external air inlet setpoint (2) and the mathematical model for calculating the external air inlet of the glass melting furnace (4) is used to adjust the opening of the induced draft fan inlet valve, control the flue gas flow through the inlet valve, and suppress External air intake is controlled to keep the amount of external air entering the glass melting furnace within a set range. The mathematical model (4) for calculating the amount of external air entering the glass melting furnace is connected to the total flue Ar content (5), the total flue gas flow rate (6), the actual value of the combustion air volume (7), the actual value of the compressed air volume of the spray gun (8), the mathematical model (10) for calculating the excess air coefficient of the glass melting furnace, and the induced draft fan inlet valve opening adjustment (3). The amount of external air entering the glass melting furnace is calculated based on the total flue Ar content, the total flue gas flow rate, the actual value of the combustion air volume, and the actual value of the compressed air volume of the spray gun. The calculation results are sent to the induced draft fan inlet valve opening adjustment (3) and the mathematical model (10) for calculating the excess air coefficient of the glass melting furnace. The total flue Ar content (5) The mathematical model (4) for calculating the amount of air entering the glass melting furnace and the on-site process equipment (29) of the glass melting furnace are connected; the total flue gas flow rate (6) is connected to the mathematical model (4) for calculating the amount of air entering the glass melting furnace and the on-site process equipment (29) of the glass melting furnace; the actual value of the combustion air volume (7) is connected to the mathematical model (4) for calculating the amount of air entering the glass melting furnace and the on-site process equipment (29) of the glass melting furnace; the actual value of the compressed air volume of the spray gun (8) is connected to the mathematical model (4) for calculating the amount of air entering the glass melting furnace and the on-site process equipment (29) of the glass melting furnace; the input of the proportion coefficient k (9) is connected to the mathematical model (10) for calculating the excess air coefficient of the glass melting furnace and the HMI operation station (1) of the glass melting furnace control system. The mathematical model for calculating the excess air coefficient of the glass melting furnace (10) is connected to the mathematical model for calculating the amount of air entering the glass melting furnace (4), the set value of the excess air coefficient (11), the total amount of O2 in the flue (12), the adjustment of air regulating valve i (13) and the adjustment of air regulating valve n (14). Based on the mathematical model for calculating the amount of air entering the glass melting furnace, the mathematical model for calculating the excess air coefficient of the glass melting furnace is derived. The difference between the set value of the excess air coefficient and the calculated value of the excess air coefficient of the glass melting furnace is used to adjust the air regulating valves i~n, and to dynamically control the excess air coefficient of the glass melting furnace. The set value of the excess air coefficient (11) is the set value, which is input by the human-machine interface of the glass melting furnace control system HMI operation station (1).The total flue gas O2 quantity (12) is the actual value of O2 quantity, which is used as a feedback value in the calculation of the excess air coefficient; the air regulating valve i regulation (13) and air regulating valve n regulation (14) are controlled variables, and the difference in the calculation of the excess air coefficient is used to adjust the air flow of air regulating valves i~n to adjust the excess air coefficient; the air-fuel ratio (15) is input from the human-machine interface of the glass melting furnace control system HMI operation station (1); the hot spot temperature setpoint (16) is the setpoint, which is input from the human-machine interface of the glass melting furnace control system HMI operation station (1); the actual hot spot temperature value (17) is the hot spot temperature feedback value; the gas regulating valve i regulation (18) and gas regulating valve n regulating (19) are controlled variables. Based on the difference between the hot spot temperature setpoint and the actual hot spot temperature, the flow rate of gas regulating valve i~n is adjusted to dynamically control the hot spot temperature; the glass melting furnace CO setpoint (20) is the setpoint, which is input by the human-machine interface of the glass melting furnace control system HMI operation station (1); the total flue CO actual value (21) is the actual CO detection value, which is compared with the glass melting furnace CO setpoint (20) as negative feedback. The difference is used to adjust the flow rate of gas regulating valve i~n to improve the combustion condition; the melting section end pressure setpoint (22) is the setpoint, which is determined by the glass melting furnace control system HMI operation station (1). The kiln control system HMI operation station (1) inputs human-machine interface; the induced draft fan air volume adjustment (23) is connected to the set value (22) of the melting section end pressure, the actual value (24) of the melting section end pressure and the glass melting furnace on-site process equipment (29), and adjusts the induced draft fan air volume according to the difference between the set value of the melting section end pressure and the actual value of the melting section end pressure feedback, and dynamically controls the melting section end pressure; the glass melting furnace temperature i detection (25) and glass melting furnace temperature n detection (26) are temperature i~n detections set on the glass melting furnace body and pipeline. Depending on the specific furnace conditions, the number of temperature detection points and detection locations will vary. Similarly, these temperature detection signals are sent to the glass melting furnace control system HMI operation station (1) for temperature status monitoring, trend curve recording, and fault tracing; the glass melting furnace pressure i detection (27) and glass melting furnace pressure n detection (28) are pressure i~n detections set on the glass melting furnace body and pipeline. Depending on the specific furnace conditions, the number of pressure detection points and detection locations will vary. These pressure detection signals are sent to the glass melting furnace control system HMI operation station (1) for pressure status monitoring, trend curve recording, and fault tracing; the glass melting furnace field process equipment (29) is the glass melting furnace field online equipment.

[0040] This technical solution is passed Figure 2 The control system configuration diagram of the dynamic control method for the asymmetric characteristics of the glass melting furnace and its flue gas pipeline network shown is implemented. Figure 2The main process control system (1) of the glass melting furnace is the main control system of the glass melting furnace, including the control of the glass melting furnace body and its auxiliary equipment, and is connected to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas pipeline network; the HMI operation station (2) of the glass melting furnace control system is a computer-based human-machine interface for operation and screen display, and is connected to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas pipeline network; the external air intake setpoint (3) is the system control target setpoint, which comes from the HMI operation station (2) of the glass melting furnace control system and is sent to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas pipeline network; the air excess coefficient setpoint (4) is the system control target setpoint. The target setpoint is obtained from the glass melting furnace control system HMI operation station (2) and sent to the glass melting furnace and its flue gas network asymmetric system dynamic controller (10); the glass melting furnace CO setpoint (5) is the system control target setpoint, obtained from the glass melting furnace control system HMI operation station (2) and sent to the glass melting furnace and its flue gas network asymmetric system dynamic controller (10); the melting section end pressure setpoint (6) is the system control target setpoint, obtained from the glass melting furnace control system HMI operation station (2) and sent to the glass melting furnace and its flue gas network asymmetric system dynamic controller (10); the hot spot temperature setpoint (7) is the system control target setpoint, obtained from the glass melting furnace control system HMI operation station (2) and sent to the glass melting furnace and its flue gas network asymmetric system dynamic controller (10); The HMI operator station (2) of the glass melting furnace control system sends data to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas pipeline network; the air-fuel ratio setting input (8) is the system control setting value, which comes from the HMI operator station (2) of the glass melting furnace control system and is sent to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas pipeline network; the proportion coefficient k input (9) is the system mathematical model calculation input data, which comes from the HMI operator station (2) of the glass melting furnace control system and is sent to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas pipeline network; the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas pipeline network is the core of the dynamic control of the asymmetric system of the glass melting furnace and its flue gas pipeline network, which is composed of... Composed of DCS or similar digital controllers, it has its own mathematical model for calculating the amount of external air entering the glass melting furnace, mathematical model for calculating the excess air coefficient of the glass melting furnace, closed-loop dynamic control of the amount of external air entering the glass melting furnace, and closed-loop dynamic control software for the excess air coefficient of the glass melting furnace; the total flue Ar content detection (11) is the actual value of the total flue Ar content detection, which is sent to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas pipeline network for the mathematical model to calculate the amount of external air entering; the total flue O2 content detection (12) is the value of the total flue O2 content detection, which is sent to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas pipeline network for the mathematical model to calculate the amount of oxygen in the amount of external air entering;The total flue gas CO content detection (13) is the total flue gas CO content detection value, which is sent to the dynamic controller (10) of the glass melting furnace and its flue gas pipeline asymmetric system to adjust the gas regulating valve i~n and control the CO content; the total flue gas flow detection (14) is the actual value of the total flue gas flow, which is connected to the dynamic controller (10) of the glass melting furnace and its flue gas pipeline asymmetric system to calculate the amount of external air entering the system using a mathematical model; the actual value of the combustion air volume (15) is the combustion air volume detection value, which is sent to the dynamic controller (10) of the glass melting furnace and its flue gas pipeline asymmetric system to calculate the amount of external air entering the system using a mathematical model; the spray gun compressed air volume detection (16) is the spray gun compressed air volume detection value. The value is sent to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas network for mathematical model calculation of the amount of external air entering; the end pressure detection (17) of the melting section is the actual value of the end pressure detection of the melting section, which is sent to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas network for adjusting the air volume of the induced draft fan and dynamically controlling the end pressure of the melting section; the hot spot temperature detection (18) is the actual value of the hot spot temperature detection, which is sent to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas network for dynamic adjustment of the hot spot temperature; the induced draft fan inlet valve opening adjustment (19) is connected to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas network for adjusting the opening of the induced draft fan inlet valve. The system is configured to suppress the entry of external air and control the amount of external air entering. The induced draft fan airflow regulator (20) is connected to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas network for dynamic pressure regulation at the end of the melting section. Air regulating valve i (21) and air regulating valve n (22) are connected to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas network for temperature regulation and excess air coefficient regulation. Gas regulating valve i (23) and gas regulating valve n (24) are connected to the dynamic controller (10) of the asymmetric system of the glass melting furnace and its flue gas network for temperature regulation and CO regulation. The glass melting furnace temperature i is detected (25). The glass melting furnace temperature n detector (26) is connected to the glass melting furnace and its flue gas pipeline asymmetric system dynamic controller (10) for glass melting furnace temperature monitoring, recording, and fault analysis; the glass melting furnace pressure i detector (27) and glass melting furnace pressure n detector (28) are connected to the glass melting furnace and its flue gas pipeline asymmetric system dynamic controller (10) for glass melting furnace pressure monitoring, recording, and fault analysis; the field process equipment process information (29) collects the operating signals and status information of the equipment and detectors of the glass melting furnace field process equipment (30) and sends them to the glass melting furnace and its flue gas pipeline asymmetric system dynamic controller (10); the glass melting furnace field process equipment (30) is the glass melting furnace field online equipment.

[0041] To improve the thermal efficiency of glass melting furnaces, it is necessary to control not only the excess air coefficient but also the amount of external air entering the furnace. Controlling the excess air coefficient optimizes combustion performance, while controlling the amount of external air entering the furnace reduces heat loss and stabilizes pressure. Achieving these two controllable aspects breaks through the technical bottlenecks that restrict existing technologies, enabling dynamic control of the asymmetric glass melting furnace system.

[0042] Dynamic control system for external air intake of glass melting furnace In the calculation of the external air intake of the glass melting furnace using the mathematical model in equation (1), the method of calculating the external air intake by detecting the argon content in the flue gas is a very simple, accurate, and reliable method. The opening of the induced draft fan inlet valve is adjusted according to the deviation between the set value and the calculated value of the external air intake, so that the opening of the inlet valve basically matches the actual furnace gas volume of the glass melting furnace, thus suppressing the intake of external air. Furthermore, the speed of the induced draft fan is adjusted by detecting the pressure at the end of the melting section, and the pressure at the end of the melting section is dynamically controlled. This solves the problem of uncontrollable asymmetric systems in glass melting furnaces, even when the glass melting furnace is under heavy load. With a reduced load, the furnace pressure decreases due to the adjustment function of the dynamic control system for the amount of external air entering the glass melting furnace. This is achieved by adjusting the opening of the induced draft fan inlet valve. The furnace pressure regulation system then adjusts the speed of the induced draft fan to achieve a new balance in the furnace pressure. The pressure disturbance caused by changes in the glass melting furnace load is effectively controlled, preventing pressure runaway. When the opening of the induced draft fan inlet valve is basically matched with the actual furnace gas volume, the characteristics of the fan network are also significantly improved. The speed range of the induced draft fan is greatly increased, preventing fan surge and meeting the energy-saving optimization requirements of the induced draft fan across all operating conditions.

[0043] Stable pressure is one of the necessary conditions for the normal operation of a glass melting furnace. Only when the amount of external air entering the glass melting furnace is effectively controlled can the pressure at the end of the melting section be stably controlled. That is, in terms of physical characteristics, the amount of external air entering the glass melting furnace due to its asymmetric characteristics seriously affects the stability of the pressure at the end of the melting section. Based on controlling the opening of the induced draft fan inlet valve according to the amount of external air entering the glass melting furnace, and then using the pressure at the end of the melting section to control the speed of the induced draft fan, is the key technology for regulating the asymmetric system of the glass melting furnace.

[0044] Figure 1The technical solution block diagram of the dynamic control method for the asymmetric characteristics of glass melting furnace and its flue gas pipeline network consists of the glass melting furnace control system HMI operation station (1), external air intake setpoint (2), induced draft fan inlet valve opening adjustment (3), glass melting furnace external air intake calculation mathematical model (4), total flue gas Ar content (5), total flue gas flow rate (6), actual value of combustion air volume (7), actual value of compressed air volume of spray gun (8), melting section end pressure setpoint (22), induced draft fan volume adjustment (23), actual value of melting section end pressure (24), and glass melting furnace on-site process equipment (29), which constitute the closed-loop dynamic control system for external air intake of glass melting furnace.

[0045] Dynamic control system for excess air coefficient in glass melting furnace The method involves detecting the oxygen and carbon monoxide content in the flue gas, calculating the excess air coefficient based on a mathematical model for glass melting furnaces, and then adjusting the flow rate of the air regulating valve based on the difference between the set value and the calculated value of the excess air coefficient. Additionally, the flow rate of the gas regulating valve is adjusted based on the difference between the detected CO value and the set CO value, so that the excess air coefficient remains stable within the set range.

[0046] Figure 1 The technical solution block diagram of the dynamic control method for the asymmetric characteristics of glass melting furnace and its flue gas pipeline network consists of the glass melting furnace control system HMI operation station (1), proportion coefficient k input (9), glass melting furnace air excess coefficient calculation mathematical model (10), air excess coefficient set value (11), total flue gas O2 quantity (12), air regulating valve i regulation (13), air regulating valve n regulation (14), air-fuel ratio (15), hot spot temperature set value (16), hot spot temperature actual value (17), gas regulating valve i regulation (18), gas regulating valve n regulation (19), glass melting furnace CO set value (20), total flue gas CO actual value (21), and glass melting furnace on-site process equipment (29), which constitute the glass melting furnace air excess coefficient closed-loop dynamic control system.

[0047] In practical engineering applications, the amount of external air entering the glass melting furnace cannot be 0, the excess air coefficient cannot be 1, and the amount of CO in the flue gas cannot be 0. Therefore, this technical solution sets the set value for the amount of external air entering the glass melting furnace, the set value for the excess air coefficient, and the set value for CO in the glass melting furnace. These set values ​​are determined by the glass melting furnace process engineer based on the specific operating conditions of the glass melting furnace and are input into the HMI operation station of the glass melting furnace control system.

[0048] The asymmetric dynamic control method for glass melting furnaces and their flue gas pipelines is characterized by its scientific, rational, and effective utilization of the two closed-loop dynamic control systems: the closed-loop dynamic control system for the external air intake of the glass melting furnace and the closed-loop dynamic control system for the excess air coefficient of the glass melting furnace. The system is simple, reliable, stable, and efficient in operation, and easy to debug, making it suitable for realizing fully automatic dynamic control of glass melting furnaces.

[0049] Compared with existing technologies, the dynamic control method for the asymmetric characteristics of glass melting furnaces and their flue gas pipelines has broken through technical bottlenecks, opening up a new and broad vision and space for glass melting furnaces to achieve deep energy saving and emission reduction, increased production and quality assurance. It has outstanding substantive features and significant progress, and its beneficial characteristics are: The theory of asymmetric systems for glass melting furnaces was proposed for the first time, laying a theoretical foundation for breaking through the technical bottleneck that has long plagued the control of glass melting furnaces. A dynamic control method for an asymmetric system of glass melting furnace was proposed for the first time, which makes the amount of external air entering the glass melting furnace controllable and the excess air coefficient controllable. (c) A mathematical model for calculating the amount of external air entering the glass melting furnace and a closed-loop dynamic control technology for the amount of external air entering the glass melting furnace were developed; (d) A mathematical model for calculating the excess air coefficient of a glass melting furnace and a closed-loop dynamic control technology for the excess air coefficient of a glass melting furnace were developed; (e) Effective and stable control of furnace pressure and fully automatic control of glass melting furnace in asymmetric system were achieved; (f) By realizing dynamic control of external air intake and excess air coefficient, gas consumption is saved, heat loss of glass melting furnace is reduced, NOx emissions are reduced, and thermal efficiency of glass melting furnace is improved. (g) Because the glass melting furnace has been fully automated, the labor intensity of operators has been reduced and the production rate has been improved; (h) Significant improvements in the characteristics of the fan duct network have enabled the induced draft fan to achieve deep energy savings; (i) The controllable amount of external air entering and the controllable excess air coefficient enable the emission of pollutants from glass melting furnace flue gas, which is a member of the furnace, to be fundamentally controlled. This can fundamentally solve the smog problem and is of great significance to the country's air pollution control.

[0050] The dynamic control method for asymmetric characteristics of glass melting furnaces and their flue gas pipelines can be widely applied to newly built, expanded, and renovated glass melting furnace systems. The technical solution described herein is merely an example of one application area of ​​the invention and is not intended to limit the invention. Although the invention has been described in detail with reference to the example, those skilled in the art can still modify the technical solutions described in the example or make equivalent substitutions for some of the technical features. All modifications, equivalent substitutions, and improvements made within the control principles and control strategies of the invention should be included within the scope of protection of the invention.

Claims

1. A method for dynamic control of the asymmetric characteristics of a glass melting furnace and its flue gas pipeline network, characterized in that... The amount of external air entering the furnace is calculated by analyzing the argon content in the flue gas. Then, the opening of the induced draft fan inlet valve is adjusted according to the difference between the set value and the calculated value of the external air entering the furnace, thus forming a closed-loop dynamic adjustment system for the amount of external air entering the furnace, so that the amount of external air entering the furnace is always controlled within the set value range. The air flow rate and gas flow rate are adjusted according to the oxygen content and carbon monoxide content detected by flue gas analysis to control the excess air coefficient of the glass melting furnace, thus forming a closed-loop dynamic adjustment system for the excess air coefficient, so that the excess air coefficient is always controlled within the set value range. The amount of external air entering the furnace and the excess air coefficient are calculated and dynamically controlled according to the mathematical models (1), (2), (3), and (5). Equation (1) is a mathematical model for calculating the amount of external air entering a glass melting furnace; Q air =(Q w1 × A rw1 -(Q i1 +Q i2 )×A rb )×100 / 0.934 (1) In the formula: Q i1 Combustion air flow rate, m 3 / s; Q i2 : Compressed air volume of the spray gun, m 3 / s; A rb : Standard argon mole fraction in air, mol% Q w1 Total flue gas flow rate, m 3 / s; A rw1 Argon mole fraction in total flue gas, mol% Q air Air volume entering the glass melting furnace (m) 3 / s; Equation (2) is the mathematical model for calculating the oxygen volume flow rate in the external air intake of the glass melting furnace; O 2e =(Q w1 × A rw1 -(Q i1 +Q i2 )×A rb )×20.95 / 0.934 (2) In the formula: O 2e Oxygen volumetric flow rate in the external air intake of a glass melting furnace, in m³ 3 / s; The actual value of oxygen content in the excess air coefficient is calculated by the mathematical model for calculating oxygen content in the excess air coefficient, which is given by equation (3). Oh 2a =(Q w1 ×O 21 -kO 2e ) / Q w1 (3) In the formula: O 2a The actual oxygen content in the excess air coefficient, % O 21 Oxygen mole fraction in total flue gas, mol% k: Proportion coefficient, 0~1; The actual value of the excess air coefficient is calculated using the mathematical model for calculating the excess air coefficient, as shown in equation (5). α=20.95 / (20.95-(Q w1 ×O 21 - kO 2e )÷Q w1 (5) In the formula: α: Excess air coefficient, >0.

2. The method according to claim 1, characterized in that... The closed-loop dynamic adjustment system for the external air intake of the glass melting furnace described in this method includes the glass melting furnace control system HMI operation station (1), external air intake setpoint (2), induced draft fan inlet valve opening adjustment (3), glass melting furnace external air intake calculation mathematical model (4), total flue gas Ar content (5), total flue gas flow rate (6), actual value of combustion air volume (7), actual value of compressed air volume of spray gun (8), melting section end pressure setpoint (22), induced draft fan volume adjustment (23), actual value of melting section end pressure (24), and glass melting furnace on-site process equipment (29). The glass melting furnace air excess coefficient closed-loop dynamic adjustment system includes a glass melting furnace control system HMI operation station (1), a glass melting furnace external air intake calculation mathematical model (4), a proportion coefficient k input (9), a glass melting furnace air excess coefficient calculation mathematical model (10), an air excess coefficient set value (11), a total flue gas O2 quantity (12), an air regulating valve i adjustment (13), an air regulating valve n adjustment (14), an air-fuel ratio (15), a hot spot temperature set value (16), a hot spot temperature actual value (17), a gas regulating valve i adjustment (18), a gas regulating valve n adjustment (19), a glass melting furnace CO set value (20), a total flue gas CO actual value (21), and glass melting furnace on-site process equipment (29).

3. The method according to claim 1, characterized in that... The amount of external air entering the glass melting furnace is calculated by detecting inert gases in the flue gas.

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