Method for prolonging service cycle of high-temperature section heat accumulator of double-heat-accumulating type heating furnace

Abstract

The invention discloses a method for prolonging the service cycle of a high-temperature section heat accumulator of a double-heat-accumulating type heating furnace, and belongs to the technical field of steel rolling heating furnaces. The size of the baffle brick is set to be 440 mm * 200 mm * 120 mm; the first heating temperature is set to be 1000-1050 DEG C, and the second heating temperature is set to be 1150-1200 DEG C; the temperature of a high-temperature section hearth is set to be 1250-1280 DEG C; the range of the exhaust gas temperature is controlled to be 120-160 DEG C; the gas pressure is controlled to be 8 kPa to 9 kPa; the problem of how to prolong the service life of the high-temperature section heat accumulator in the double-heat-accumulating type heating furnace is solved; the control method is improved in multiple aspects, the performance of the heating furnace is greatly improved, the service life of the heating furnace is greatly prolonged, loss of the heat accumulator is reduced, and therefore the service cycle of the heat accumulator in the high-temperature section is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of steel rolling heating furnaces, and in particular relates to a method for extending the service life of a heat storage body in a high-temperature section of a double heat storage heating furnace. Background Art

[0002] As we all know, the steel rolling heating furnace is the core link in the steel production process and plays a vital role in the entire steel production process. The steel rolling heating furnace is used to heat the steel billet or ingot to the appropriate temperature for subsequent rolling processing. Among them, the double regenerative heating furnace is a common type of steel rolling heating furnace, which improves thermal efficiency by alternating two sets of regenerative bodies.

[0003] The role of the thermal storage body in the heating furnace is to store and manage thermal energy to improve the thermal efficiency and stability of the entire system; the thermal storage body can absorb and store heat during high temperature periods, and release heat when demand peaks or the temperature drops to ensure the stability of the temperature in the furnace. This thermal energy management can reduce the dependence on instantaneous heat sources, significantly improve thermal efficiency and save energy. During the heating process, the thermal storage body effectively prevents temperature instability by buffering thermal fluctuations, which helps to ensure the quality of the processed materials.

[0004] The heat storage body used in the high temperature section usually faces a harsh working environment, so its service life is relatively short. Generally speaking, the heat storage body in the high temperature section may need to be replaced every six months. This frequent replacement not only increases production costs, but may also affect production plans and construction periods. Frequent replacement of heat storage bodies not only involves material and labor costs, but may also cause equipment downtime and affect production continuity. Therefore, how to extend the service life of the heat storage body in the high temperature section has become a key issue in improving production efficiency and reducing operating costs. Summary of the invention

[0005] The object of the present invention is to provide a method for extending the service life of the high-temperature section heat storage body of a double heat storage heating furnace, so as to solve the technical problem of extending the service life of the high-temperature section heat storage body proposed in the above background technology.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for extending the service life of a high-temperature section heat storage body of a double heat storage heating furnace, comprising:

[0008] Adding a drainer to the gas pipeline to reduce the water content in the gas can reduce the moisture entering the heating furnace and improve the combustion efficiency of the gas;

[0009] The baffle brick size is set to 440mm*200mm*120mm, which can better withstand the high temperature, pressure changes and mechanical stress in the heating furnace;

[0010] Set the temperature of the first heating section to 1000℃~1050℃, the temperature of the second heating section to 1150℃~1200℃; the temperature of the high temperature section furnace to 1250℃~1280℃,

[0011] The exhaust gas temperature range is controlled to be 120℃~160℃, which can increase the service life of the high temperature section heat storage body without changing the output quality of rolled steel;

[0012] Controlling the gas pressure at 8kPa to 9kPa can reduce the impact of gas pressure fluctuations on the heat storage baffle bricks and improve system stability.

[0013] Preferably, a drainer for reducing the water content in the gas is added to the gas pipeline;

[0014] Preferably, the first heating temperature is 1000°C or 1050°C, and the second heating temperature is 1150°C or 1200°C.

[0015] Preferably, the furnace temperature in the high temperature section is 1250°C or 1280°C.

[0016] Preferably, the exhaust gas temperature is 120°C or 160°C.

[0017] Preferably, a pressure regulating valve is added after the three major gas valves to control the gas pressure at 8 kPa to 9 kPa. The pressure regulating valve can accurately control the gas pressure.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention provides a method for extending the service life of the high-temperature section heat storage body of a double heat storage heating furnace, which solves the problem of how to extend the service life of the high-temperature section heat storage body in the double heat storage heating furnace. By making various improvements to the control method, the performance and life of the heating furnace are greatly improved, the loss of the heat storage body is reduced, and the service life of the high-temperature section heat storage body is extended.

[0020] The present invention significantly reduces the water content in the gas by adding a drainer in the gas pipeline. This reduces the moisture entering the heating furnace, thereby reducing the erosion of the moisture on the heat storage body, and at the same time improves the combustion efficiency and stability of the gas; the size of the baffle brick is adjusted to 440mm*200mm*120mm. Compared with the original size of 440mm*100mm*100mm, the new size of the baffle brick has higher bending and compressive strength. The increased width and thickness improve the connection between the brick body and the surrounding structure, reduce looseness and displacement, and improve the ability of the baffle brick to absorb and disperse thermal stress and mechanical stress impact, thereby reducing local stress concentration.

[0021] In terms of temperature management, this valve invention heats the steel billet in advance by increasing the temperature of the first and second heating sections, reducing the heat demand for the high-temperature section; despite the reduction of the furnace temperature in the high-temperature section, the steel billet still maintains a sufficient heating effect, avoiding the thermal stress and chemical erosion caused by high temperature to the heat storage body. In addition, the exhaust gas temperature is controlled between 120℃ and 160℃. This range is determined by experiments as the balance point between improving thermal efficiency and preventing corrosion, which can effectively reduce heat loss and avoid corrosion of flues and equipment.

[0022] Finally, by adding a gas pressure regulating valve, the gas pressure can be accurately controlled at 8kPa ~ 9kPa, reducing the impact on the heat storage baffle bricks, maintaining the stability of the system, and effectively mitigating the impact of mechanical stress caused by pressure fluctuations on the system.

[0023] These improvements work together to increase the life cycle of the thermal storage body from six months to a maximum of 18 months, reducing the need for frequent replacement and maintenance, thereby reducing maintenance costs and downtime and improving overall production efficiency. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are clearly and completely described below. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0025] A method for extending the service life of a high-temperature section heat storage body of a double heat storage heating furnace, comprising:

[0026] Adding a drainer to the gas pipeline to reduce the water content in the gas can reduce the moisture entering the heating furnace and improve the combustion efficiency of the gas;

[0027] Specifically, the drainer can reduce the water content in the coal gas, that is, reduce the moisture entering the heating furnace; dry coal gas burns more completely, has higher thermal efficiency, and burns more stably, which is conducive to controlling the furnace temperature; the amount of moisture entering the heating furnace is reduced, and the erosion of moisture on the heat storage body is also reduced.

[0028] The size of the baffle brick is set to 440mm*200mm*120mm; in the prior art, the size of the baffle brick is 440mm*100mm*100mm; the baffle brick of the new size can better withstand the high temperature, pressure changes and mechanical stress in the heating furnace, thereby extending the service life of the high-temperature section heat storage body, achieving the purpose of reducing refractory costs and improving heating furnace performance;

[0029] Specifically, by increasing the width and thickness of the baffle bricks, the bending and compressive strength of the baffle bricks are significantly improved. The wider brick body provides a larger contact area, making the connection between the baffle bricks and the surrounding structure more stable and reducing the possibility of loosening and displacement. The thicker brick body can better withstand thermal stress and mechanical stress, so that the baffle bricks can better absorb and disperse the impact force from the gas pressure, reduce local stress concentration, and improve impact resistance.

[0030] Set the temperature of the first heating element to 1000℃~1050℃; the temperature of the second heating element to 1150℃~1200℃; the temperature of the high temperature section furnace to 1250℃~1280℃;

[0031] Before plastic forming processes such as forging and rolling, heating of the steel billet is a necessary step; this step can make the steel billet easier to form, especially in processing that requires precise size and shape, hot processing can provide better processing conditions than cold processing. Heating makes the steel billet softer and more plastic, reducing its hardness. In this way, the steel billet is easier to deform in the subsequent rolling or forming process, reducing the force and equipment wear required during the processing. Uniform heating to a high temperature of about 1200℃ is conducive to eliminating internal stress and avoiding defects such as cracks and delamination during subsequent rolling. Temperature uniformity is crucial to the quality of the finished product. Through segmented heating of the first heating section, the second heating section and the high temperature section, the steel billet can reach a relatively uniform temperature from the inside to the surface. This uniform temperature distribution helps to avoid internal stress and defects caused by uneven cooling during processing.

[0032] In actual production, in order to ensure that the billet can reach and maintain the target temperature of 1200℃, the temperature of the heating furnace usually needs to be set slightly higher. This is due to various factors. First of all, heat loss is one of the main reasons, because during the heating process, the heat in the furnace will be dissipated to the external environment through the furnace wall and other structures, so a higher furnace temperature is required to compensate for this loss and ensure that the billet itself can reach the required temperature.

[0033] In the prior art, the furnace temperature of the first heating section is 850°C to 900°C, the furnace temperature of the second heating section is 1000°C to 1050°C; the furnace temperature of the high temperature section is 1300°C to 1320°C; the present invention can increase the service life of the high temperature section heat storage body without changing the output rolled steel quality by increasing the furnace temperature of the first heating section to 1000°C to 1050°C, the furnace temperature of the second heating section to 1150°C to 1200°C, and reducing the furnace temperature of the high temperature section to 1250°C to 1280°C;

[0034] Specifically, raising the temperature of the first and second heating sections can fully heat the metal billet in advance, thereby reducing the heat demand for the high-temperature section; since the temperatures of the first and second heating sections are higher, the billet has reached a relatively high temperature before entering the high-temperature section, so it can be heated more gently in the high-temperature section, and the overall temperature of the billet can still reach 1200°C, so appropriately lowering the temperature of the high-temperature section will not have a negative impact on the quality of the billet;

[0035] Lowering the furnace temperature in the high-temperature section can reduce the time of exposure to extreme high temperatures and the thermal stress on the internal components of the high-temperature section (including the thermal storage body); it directly reduces the thermal load and temperature shock of the thermal storage body, thereby delaying the aging and loss of the thermal storage body material. The reduction in the temperature of the high-temperature section will reduce the difference in thermal expansion and contraction of the thermal storage body, thereby reducing the thermal fatigue of the thermal storage body. High temperature will accelerate oxidation and chemical corrosion, and lower operating temperatures can reduce these effects.

[0036] Control the exhaust temperature range to 120℃~160℃; it can reduce heat loss, improve thermal efficiency, and avoid corrosion problems caused by too low temperature;

[0037] Specifically, if the exhaust gas temperature is too high (over 160°C), a large amount of heat will be discharged with the flue gas, resulting in energy waste. Controlling the temperature within 120°C to 160°C can significantly recover the heat in the flue gas and improve the thermal efficiency of the heating furnace.

[0038] If the exhaust temperature is too low (below 120°C), water vapor in the flue gas may condense; the condensed water combines with sulfides in the flue gas to form acidic substances, causing corrosion of the flue and other equipment.

[0039] The temperature range of 120℃~160℃ is the balance point found through many experiments between improving thermal efficiency and preventing corrosion. This temperature range can not only ensure higher thermal efficiency but also avoid low-temperature corrosion problems.

[0040] By adding a pressure regulating valve after the three major gas valves, the gas pressure can be controlled at 8kPa to 9kPa; the impact of gas pressure fluctuations on the heat storage baffle bricks can be reduced, improving system stability;

[0041] Specifically, precise pressure control can significantly reduce fluctuations in gas pressure. Stable pressure means that the gas flows more evenly, reducing the impact force on the baffle bricks of the thermal storage body. High pressure or pressure fluctuations will cause greater mechanical stress on the baffle bricks, and stable pressure can minimize this stress.

[0042] Controlling the gas pressure at 8kPa to 9kPa, improving the baffle brick size, and controlling the furnace temperature work together to comprehensively improve the performance and life of the heating furnace.

[0043] The present invention combines various improvements, adds a drainer to the gas pipeline for reducing the water content in the gas; sets the size of the baffle brick to 440mm*200mm*120mm; sets the temperature of the first heat exchanger to 1000℃~1050℃, and the temperature of the second heat exchanger to 1150℃~1200℃; sets the temperature of the high-temperature section furnace to 1250℃~1280℃; controls the exhaust gas temperature range to 120℃~160℃; controls the gas pressure to 8kPa~9kPa; and finds through actual production that the service life of the high-temperature section heat storage body is significantly extended from the original six months to 12 months, and the longest service life reaches 18 months.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for extending the use period of the heat storage body in the high temperature section of a double heat storage heating furnace, characterized in that: include: Add drains to gas pipelines to reduce the water content in gas; Set the baffle brick size to 440mm*200mm*120mm; Set the temperature of the first heating element to 1000℃~1050℃, the temperature of the second heating element to 1150℃~1200℃; the temperature of the high temperature section furnace is set to 1250℃~1280℃; Control the exhaust temperature range to 120℃~160℃; Control the gas pressure at 8kPa ~ 9kPa.

2. The method for extending the use period of the high temperature section heat storage body of the double heat storage heating furnace according to claim 1 is characterized in that: Add a drainer to the gas pipeline to reduce the water content in the gas.

3. The method for extending the use period of the high temperature section heat storage body of the double heat storage heating furnace according to claim 1 is characterized in that: The first heating temperature is 1000℃ or 1050℃, and the second heating temperature is 1150℃ or 1200℃.

4. The method for extending the use period of the high temperature section heat storage body of the double heat storage heating furnace according to claim 1 is characterized in that: The furnace temperature in the high temperature section is 1250℃ or 1280℃.

5. The method for extending the service life of the high temperature section heat storage body of a double heat storage heating furnace according to claim 1, characterized in that: The exhaust temperature is 120℃ or 160℃.

6. The method for extending the use period of the high temperature section heat storage body of the double heat storage heating furnace according to claim 1 is characterized in that: The gas pressure is controlled at 8kPa~9kPa by adding a pressure regulating valve after the three major gas valves.