Burner and heating furnace
By designing a non-axially symmetrical burner and an independently adjusted gas supply pipeline, the problem of excessive combustion local temperature of the rolling steel heating furnace during oxygen-rich combustion is solved, and the ultra-low nitrogen oxide emission and the energy-saving and carbon reduction effect of the heating furnace is achieved.
Patent Information
- Application Number
- CN202420557449.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-21
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2034-03-21
AI Technical Summary
In the oxygen-rich combustion, existing steel rolling furnaces are prone to cause excessive local combustion temperatures, producing high-temperature thermal nitrogen oxides, and are difficult to adapt to the unstable conditions of fuels and oxygen sources of different calorific values, and cannot meet the requirements of low-carbon production.
A burner is designed, with a gas nozzle, an oxygen nozzle, a primary air nozzle and a secondary air nozzle at the end, and is arranged non-axially symmetrically, and the switching between conventional combustion, oxygen-rich combustion and full oxygen combustion is achieved through an independently adjusted gas supply pipeline.
It achieves ultra-low nitrogen oxide emissions under different oxygen concentration combustion methods, adapts to the unstable conditions of different fuel components and oxygen sources, and improves the energy-saving and carbon reduction effect of the heating furnace.
Smart Images
Figure CN222937804U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of rolling mill heating furnaces, and particularly relates to a burner and a heating furnace. Background Technique
[0002] The steel rolling heating furnace is one of the key equipment in the hot rolling production line of the iron and steel industry, and has a great influence on the quality of the final product and the total energy consumption. The steel rolling heating furnace is a high-energy-consuming equipment, and its energy consumption usually accounts for about 60% of the energy consumption of the whole hot rolling production line.
[0003] With the increasingly fierce market competition and the higher and higher environmental protection requirements, while ensuring the heating quality of the products, how to reduce the fuel consumption of the heating furnace and reduce environmental pollution to achieve low-carbon production has attracted widespread attention. Among them, the oxy-fuel combustion technology has attracted increasing attention due to its remarkable energy-saving effect. Due to the increase in the oxygen content in the combustion-supporting air, the oxy-fuel combustion technology reduces the proportion of inert gases in the combustion-supporting air and increases the theoretical combustion temperature; in addition, due to the reduction of the flue gas volume, the heat loss of the flue gas is reduced, and it has a good energy-saving and carbon-reducing effect. In the past few decades, the small-scale application of oxy-fuel combustion in industrial furnaces has been widely recognized.
[0004] The heating furnace system of traditional pipeline oxy-fuel combustion includes a gas pipeline system, a combustion-supporting gas pipeline system, a gas heat exchanger, a combustion-supporting gas heat exchanger, a combustion system and a furnace body. The combustion system includes an oxy-fuel burner, a combustion-supporting gas regulating valve, a gas regulating valve and a control system. The gas introduced into the gas pipeline system is preheated by the gas heat exchanger and then introduced into the oxy-fuel burner. The combustion-supporting gas introduced into the combustion-supporting gas pipeline system is preheated by the combustion-supporting gas heat exchanger and then introduced into the oxy-fuel burner. The supply flow rates of the gas and the combustion-supporting gas are adjusted through the combustion-supporting gas regulating valve, the gas regulating valve and the burner control system. Since the oxygen is enriched in the combustion-supporting air pipeline, it can adapt to the combustion heating of low-calorific-value gas, but for the oxy-fuel combustion of gas with a higher calorific value, it is easy to cause too high local combustion temperature; secondly, since the gas and the gas are mixed and ejected in the oxy-fuel burner for combustion, when the oxygen enrichment concentration is high, the flame combustion length is short, which is not conducive to the uniform heating of the steel billet in a wide furnace; thirdly, since the local peak combustion temperature is too high, it is easy to generate high-temperature thermal nitrogen oxides, which is not conducive to meeting the ultra-low emission requirements; in addition, the adaptability range of high-calorific-value fuels is limited, and for high-concentration oxygen combustion such as full-oxygen combustion, it cannot be adapted only by pipeline oxygen enrichment, and it is difficult to meet the complex working conditions that vary in actual engineering applications.
[0005] At the same time, due to the limitations of the existing production line conditions in the steel mill, there are problems such as unstable oxygen source, fluctuating fuel composition and calorific value. A single combustion method cannot well meet the production requirements and the goal of energy conservation and carbon reduction.
[0006] In view of this, based on years of production design experience in this field and related fields, the inventors of the present utility model have designed a burner and a heating furnace through repeated tests in order to solve the problems existing in the prior art. Summary of the Utility Model
[0007] The purpose of the present utility model is to provide a burner and a heating furnace that can meet the oxy-fuel combustion of fuels with different calorific values.
[0008] To achieve the above object, the present utility model provides a burner, wherein the burner includes a columnar burner body, one end of the burner body is a nozzle end, and the end face of the nozzle end is provided with a gas nozzle, an oxygen nozzle, a primary air nozzle and a secondary air nozzle. The gas nozzle and the oxygen nozzle are respectively offset on both sides of the axis of the burner body and are arranged in a non-axisymmetric manner. The primary air nozzle is arranged close to the gas nozzle, and the secondary air nozzle is arranged close to the oxygen nozzle.
[0009] The present utility model also provides a heating furnace, wherein the heating furnace has a furnace body, and the interior of the furnace body includes a preheating section, a first heating section, a second heating section and a soaking section arranged in sequence. The above-mentioned burners are respectively arranged in the first heating section, the second heating section and the soaking section, and each burner is connected with a separately adjustable gas supply pipeline.
[0010] Compared with the prior art, the present utility model has the following characteristics and advantages:
[0011] The burner and the heating furnace provided by the present utility model can achieve ultra-low nitrogen oxide emissions under different oxygen concentration combustion modes such as conventional air-assisted combustion, oxy-fuel or all-oxygen combustion. It can not only meet industrial heating under conditions such as different fuel composition fluctuations and unstable oxygen sources, but also enable the heating furnace as a whole to achieve better energy-saving and carbon-reduction effects. Description of the Drawings
[0012] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure of the present utility model in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only schematic and are used to assist in understanding the present utility model, rather than specifically limiting the shapes and proportional dimensions of the components of the present utility model. Those skilled in the art can choose various possible shapes and proportional dimensions according to specific circumstances to implement the present utility model under the teaching of the present utility model.
[0013] Figure 1 It is a schematic structural diagram of the burner provided by the present utility model;
[0014] Figure 2 It is a schematic structural diagram of the furnace body of the heating furnace in the present utility model;
[0015] Figure 3Schematic diagram of the composition of the heating furnace in the present utility model;
[0016] Figure 4 Schematic diagram of the composition of the gas supply pipeline in the present utility model.
[0017] Description of reference numerals in the drawings
[0018] 100, burner; 110, burner body;
[0019] 120, gas nozzle; 130, oxygen nozzle;
[0020] 140, primary air nozzle; 150, secondary air nozzle;
[0021] 200, heating furnace; 210, furnace body;
[0022] 211, preheating section; 212, first heating section;
[0023] 213, second heating section; 214, soaking section;
[0024] 220, gas supply pipeline; 221, gas branch pipe;
[0025] 222, oxygen branch pipe; 223, air branch pipe;
[0026] 224, gas regulating valve; 225, oxygen regulating valve;
[0027] 226, flap valve. Detailed implementation manners
[0028] Combined with the description of the specific implementation manners of the present utility model and the drawings, the details of the present utility model can be more clearly understood. However, the specific implementation manners of the present utility model described herein are only for the purpose of explaining the present utility model and cannot be understood in any way as a limitation of the present utility model. Under the teaching of the present utility model, those skilled in the art can conceive any possible variations based on the present utility model, and all of these should be regarded as belonging to the scope of the present utility model.
[0029] As Figure 1 , Figure 2 shown, the present utility model provides a burner 100 for a heating furnace 200. The burner 100 includes a columnar burner body 110. One end of the burner body is a nozzle end, and the end face of the nozzle end is provided with a gas nozzle 120, an oxygen nozzle 130, a primary air nozzle 140, and a secondary air nozzle 150. The gas nozzle 120 and the oxygen nozzle 130 are respectively offset on both sides of the axis of the burner body 110 and are arranged non-axially symmetrically. The primary air nozzle 140 is arranged close to the gas nozzle 120, and the secondary air nozzle 150 is arranged close to the oxygen nozzle 130.
[0030] The burner 100 proposed by the present utility model has the secondary air nozzle 150 and the oxygen nozzle 130 offset to one side of the gas nozzle 120 to form an asymmetric arrangement structure. By offsetting the secondary air nozzle 150 and the oxygen nozzle 130, an asymmetric flame shape and temperature distribution can be formed. In the case of a relatively high oxygen enrichment concentration, there is no conventional high-temperature flame area, avoiding the intense flame combustion formed by the axially symmetric annular array arrangement of the secondary air nozzles of the traditional burner around the gas nozzle. Therefore, the burner 100 proposed by the present utility model not only realizes flameless combustion with uniform temperature and ultra-low nitrogen emissions, but also avoids excessive temperature difference in the furnace combustion area, prevents local overheating during billet heating, thereby improving the temperature uniformity of the billet heating and reducing the oxidation loss of the billet.
[0031] In an optional embodiment of the present utility model, the primary air nozzle 140 is annular and sleeved outside the gas nozzle 120. With the above structure, after the gas is ejected from the gas nozzle 120, it can be mixed with the surrounding primary air, which helps to achieve a faster combustion speed and a more complete combustion process. At the same time, by adjusting the flow rate and speed of the primary air, the temperature and shape of the flame can be controlled, and thus the degree of gas combustion can be adjusted more flexibly.
[0032] In an optional embodiment of the present utility model, two secondary air nozzles 150 are provided at intervals at the nozzle end, and the oxygen nozzle 130 is located between the two secondary air nozzles 150. With the above structure, the two secondary air nozzles 150 are respectively located on both sides of the oxygen nozzle 130, which can effectively supplement the additional air required for combustion and ensure the uniform distribution of oxygen in the entire combustion area; at the same time, the secondary air also helps to cool the burner body 110 itself to prevent it from overheating.
[0033] In an optional example of the present utility model, the secondary air nozzle 150 is arc-shaped, which helps the secondary air to be sprayed into the furnace or combustion area in a more uniform manner.
[0034] As Figure 3 shown, the present utility model also proposes a heating furnace 200, which has a furnace body 210. The interior of the furnace body 210 includes a preheating section 211, a first heating section 212, a second heating section 213, and a soaking section 214 arranged in sequence. The first heating section 212, the second heating section 213, and the soaking section 214 are respectively provided with the burners 100 as described above, and each burner 100 is respectively connected to a gas supply pipeline 220 that can be independently adjusted.
[0035] The heating furnace 200 proposed by the present utility model divides the interior of its furnace body 210 into multiple parts such as a first heating section 212, a second heating section 213, and a soaking section 214. The burners 100 of each of the above parts are respectively and independently connected to gas supply pipelines. By adjusting the gas supply pipelines, the burners 100 can achieve three different combustion modes: conventional combustion, oxygen-enriched combustion, and all-oxygen combustion. In this way, when the heating furnace 200 heats the billet, more reasonable combustion modes can be selected for each section according to the functional requirements of the first heating section 212, the second heating section 213, and the soaking section 214. Through the combination of multiple combustion modes, the radiation heat transfer efficiency in the heating furnace 200 can be significantly improved, the heating time can be reduced, and the output per unit time can be increased.
[0036] In the heating furnace 200 proposed by the present utility model, the oxygen nozzles 130 and the gas nozzles 120 of each burner 100 are arranged in a non-axisymmetric structure, which can form an asymmetric flame shape and temperature distribution. In the case of a relatively high oxygen-enriched concentration, there is no conventional high-temperature flame area. Under different oxygen concentration combustion modes such as conventional air-assisted combustion, oxygen-enriched or all-oxygen combustion, ultra-low nitrogen oxide emissions can be achieved, enabling the overall heating furnace 200 to achieve better energy-saving and carbon-reduction effects.
[0037] The heating furnace 200 proposed by the present utility model can switch between conventional combustion, oxygen-enriched combustion, and all-oxygen combustion through the independently adjustable gas supply pipelines 220 of each burner 100. It can meet the industrial heating requirements under fluctuating conditions such as different fuel calorific value changes and unstable oxygen sources in steel mills, and can achieve different combustion mode differentiations in different zones of the heating furnace according to the functional requirements of different zones.
[0038] In an optional embodiment of the present utility model, as Figure 4 shown, the gas supply pipeline 220 includes a gas branch pipe 221, an oxygen branch pipe 222, and an air branch pipe 223. The gas branch pipe 221 is connected to the gas nozzle 120 through a gas regulating valve 224. The oxygen branch pipe 222 is connected to the oxygen nozzle 130 through an oxygen regulating valve 225. The air branch pipe 223 is respectively connected to the primary air nozzle 140 and the secondary air nozzle 150 through a flap valve 226. Specifically, by adjusting the opening and closing and valve opening of the gas regulating valve 224, the flow rate of the gas at the gas nozzle 120 can be adjusted. By adjusting the opening and closing and valve opening of the oxygen regulating valve 225, the flow rate of the oxygen at the oxygen nozzle 130 can be adjusted. By using the flap valve, the ratio of the primary air entering the primary air nozzle 140 and the secondary air entering the secondary air nozzle 150 can be adjusted.
[0039] In an alternative embodiment of the present utility model, the interior of the furnace body 210 has a horizontally arranged billet transportation path. The preheating section 211, the first heating section 212, the second heating section 213, and the soaking section 214 are arranged in sequence along the billet transportation path, and burners 100 are respectively arranged above and below the billet transportation path. With the above structure, after the billet enters the heating furnace 200, it is heated from above and below, improving the uniformity of billet heating.
[0040] In an alternative example of this embodiment, the burners 100 are horizontally arranged and have an angle with the billet transportation path. The secondary air nozzles 150 and oxygen nozzles 130 on the burners 100 are located on the side far from the billet transportation path. With the above structure, the secondary air and oxygen ejected by the burners 100 are located on the side far from the billet, and the gas ejected by the burners 100 is located on the side close to the billet, ensuring a reducing atmosphere on the billet surface and reducing oxidation loss.
[0041] In an alternative example, the axis of the burner 100 is perpendicular to the billet transportation path.
[0042] In an alternative embodiment of the present utility model, the heating furnace 200 further includes components such as a gas preheater, an air preheater, a burner, and a fan. After the air is preheated by the air preheater by the fan, it enters the air branch pipe 223, and then the ratio of the primary air and the secondary air is adjusted by the front flap valve of the burner 100. After the gas is preheated by the gas preheater, it enters the burner 100 through the gas branch pipe 221 to participate in combustion. After the oxygen is connected from the oxygen connection point, it passes through a valve group composed of components such as a stop valve, a filter, a pressure regulating valve, a flow meter, and a flame arrester, and then enters the oxygen nozzle 130 of the burner 100 through the oxygen branch pipe 222. By adjusting the opening and closing and valve opening degrees of the gas regulating valve 224 and the oxygen regulating valve 225 in front of the burner 100, conventional combustion, oxygen-enriched combustion, and all-oxygen combustion can be realized. The combustion flue gas in the heating furnace 200 enters the flue after passing through the preheating section, preheats the air and gas passing through the air preheater and the gas preheater, and then is discharged through the chimney.
[0043] In an alternative embodiment of the present utility model, the heating furnace 200 further has a control system, and the control system is connected to each valve, and thus can remotely control the opening and closing and valve opening degrees of each valve.
[0044] The present utility model also proposes a control method for a heating furnace, which is used for the heating furnace 200 described above. The combustion modes of the first heating section 212, the second heating section 213, and the soaking section 214 can be respectively adjusted.
[0045] The present utility model also provides a control method for a heating furnace. The first heating section 212, the second heating section 213, and the soaking section 214 can adopt different combustion modes, thereby realizing the switching between conventional combustion, oxygen-enriched combustion, and all-oxygen combustion of the heating furnace 200, which can meet the flexible production requirements under fluctuating conditions such as changes in fuel calorific value and unstable oxygen source in steel mills. At the same time, according to the functional requirements of different zones of the heating furnace, different combustion modes can be realized for different zones with differentiation.
[0046] In an optional example of the present utility model, the first heating section 212 burns with an oxygen concentration of 21% - 100%; the second heating section 213 burns with an oxygen concentration of 21 - 50%; the soaking section 214 burns with an oxygen concentration between 21 - 35%. While meeting the energy conservation and carbon reduction of the heating furnace 200, it improves the heating uniformity and reduces local overheating and oxidation loss.
[0047] In the present utility model, the surface heating temperature is the most important factor affecting the oxidation loss of the steel billet. When the steel billet is heated, the higher the temperature, the greater the impact on the oxidation loss of the steel billet. The influence of the oxygen-enriched concentration in the flue gas on the oxidation loss of the steel billet is mainly reflected in the high-temperature section above 1000°C. Since the surface temperature of the steel billet during heating in the first heating section generally does not exceed 1000°C, the amount of scale generated in this interval is extremely small. Therefore, higher oxygen concentration combustion or even all-oxygen combustion can be adopted in this interval. And the heat supply of the first heating section 212 generally accounts for about 50% of the entire heating furnace 200. Using high-concentration oxygen-enriched in this interval has a more obvious energy conservation and carbon reduction effect. The surface temperature of the steel billet in the second heating section 213 begins to exceed 1000°C, and the scale generation rate increases. The heat supply ratio in this interval is about 35% or so. Therefore, the oxygen-enriched concentration in the second heating section 213 is relatively lower than that in the first heating section 212. The surface temperature of the steel billet in the soaking section 214 is close to 1200°C, and a large amount of scale is generated. The heat supply ratio in this interval only accounts for about 15%. Therefore, only a lower oxygen-enriched concentration is adopted in this interval.
[0048] In an optional example of the present utility model, the air velocity of the primary air nozzle 140, the air velocity of the secondary air nozzle 150, and the gas velocity of the gas nozzle 120 are between 30 - 80 m / s, and the oxygen velocity of the oxygen nozzle 130 is between 100 - 300 m / s.
[0049] The detailed explanations for the above-mentioned embodiments are only for the purpose of explaining the present utility model so that it can be better understood. However, these descriptions cannot be construed as any limitation to the present utility model. In particular, the various features described in different embodiments can be arbitrarily combined with each other to form other embodiments. Unless there are explicit contrary descriptions, these features should be understood to be applicable to any one of the embodiments and not limited only to the described embodiments.
Claims
1. A burner for a heating furnace, characterized in that: The burner includes a columnar burner body, one end of the burner body is a nozzle end, and the end surface of the nozzle end is provided with a gas nozzle, an oxygen nozzle, a primary air nozzle and a secondary air nozzle. The gas nozzle and the oxygen nozzle are respectively offset on both sides of the axis of the burner body and are arranged in a non-axisymmetric manner. The primary air nozzle is arranged close to the gas nozzle, and the secondary air nozzle is arranged close to the oxygen nozzle.
2. The burner according to claim 1, characterized in that The primary air nozzle is annular and is sleeved outside the gas nozzle.
3. The burner according to claim 1, characterized in that The nozzle end is provided with two secondary air nozzles which are spaced apart from each other, and the oxygen nozzle is located between the two secondary air nozzles.
4. A heating furnace, characterized in that: The heating furnace comprises a furnace body, the interior of the furnace body comprises a preheating section, a first heating section, a second heating section and a soaking section arranged in sequence, the first heating section, the second heating section and the soaking section are respectively arranged with a burner as described in any one of claims 1 to 3, and each of the burners is respectively connected to a gas supply pipeline that can be independently adjusted.
5. The heating furnace according to claim 4, characterized in that: Each of the gas supply pipelines includes a gas branch pipe, an oxygen branch pipe and an air branch pipe. The gas branch pipe is connected to the gas nozzle through a gas regulating valve, the oxygen branch pipe is connected to the oxygen nozzle through an oxygen regulating valve, and the air branch pipe is respectively connected to the primary air nozzle and the secondary air nozzle through a flap valve.
6. The heating furnace according to claim 4, characterized in that The furnace body has a horizontally arranged billet transport path inside, the first heating section, the second heating section and the soaking section are arranged in sequence along the billet transport path, and the burners are respectively arranged above and below the billet transport path.
7. The heating furnace according to claim 6, characterized in that The burner is arranged horizontally and has an angle with the billet transportation path. The secondary air nozzle and the oxygen nozzle of the burner are located on a side away from the billet transportation path.