Radiant tube gas heating furnace
Radiant tube gas heating furnace is a kind of gas radiant tube heating device. Gas radiant tube heating device is burning in the sealing sleeve. Furthermore through the sleeve surface heated by thermal radiation as the main form to transfer heat to the heated object. And not with the heated object contact.
Tube heating furnace gas radiation (gas tube furnace), is a kind of gas radiant tube heating device. Gas radiant tube heating device is burning in the sealing sleeve. Through the sleeve surface heated by thermal radiation as the main form to transfer heat to the heated object. And the object to be heated combustion product of no contact. No combustion atmosphere pollution and affect the quality of products. Similarly control and regulation of atmosphere and the heating temperature for the furnace. In the end very applicable to products of high quality requirements.
Radiant tube heating technology originated in Germany in 1936, with the continuous development of heat-resistant materials, the continuous improvement of product quality, continuous improvement of heat treatment technology, USA, Japan and Europe and other countries also widely adopt the indirect heating technology. In recent years, the technology is common in the Chinese metallurgy, machinery, light industry.
Radiant tube heating device is mainly composed of a tube body, the burner and the waste heat recovery device. The tube body is the heat energy of fuel radiation to be key components of the heating object. Due to its inner surface in direct contact with the flame and high temperature flue gas combustion, poor working environment, easy ignition, partial oxidation. If along the length direction of the pipe body there is a big difference. There will produce greater thermal stress. And the impact of airflow during combustion there will produce a certain vibration. Therefore the tube has good heat resistance, high thermal conductivity, high temperature oxidation resistance ability strong. Similarly small coefficient of thermal expansion, high structural strength and good sealing performance.
The burner is radiation core tube heating device, and it controls the power, radiation tube temperature distribution, thermal efficiency and service life. The traditional radiant tube burner common form of parallel flow burner and swirl burner, the two are the diffusion of gas and air temperature or preheat to 200 ℃ ~300 ℃ fuel mixed combustion. The combustion will produce local high temperature zone. The higher temperature peak combustion, radiant tube along the length direction the higher the obvious difference. Consequently there will cause local high temperature and oxidation corrosion of the radiation tube inner surface. Due to combustion air preheated NOx emission concentration will significantly increase.
Waste heat recovery device is an important part to improve the radiation tube heater thermal efficiency. Due to the absence of flue gas waste heat recovery device the heat loss is larger. Consequently the thermal efficiency less than 50%. In order to improve the thermal efficiency of radiant tube heating normally arranging the waste heat recovery device in the exhaust tube end. That will recove exhaust heat to preheat the combustion air. But because the waste heat recovery device is used in the ordinary room wall, heat recovery effect is not very ideal, air preheating temperature is 200~300 ℃, flue gas waste heat recovery rate of only about 30%. The traditional gas radiation heat efficiency of heating device is difficult to break through 75%.