The first task of vacuum furnace is to save energy and reduce emissions
The vacuum furnace is a major energy consumer and polluter in China, how to save energy and reduce emissions is an important issue facing China's industry.
The energy consumption of vacuum furnace is influenced by many factors but the main measures of energy saving are generally inseparable from several aspects such as optimization of design, improvement of equipment, recovery of waste heat utilization, strengthening of detection control and production management. Energy saving must have a scientific measurement and comparison test method. The currently accepted test method is the heat balance test. Through the thermal measurement of the vacuum furnace a comprehensive understanding of the thermal process of the vacuum furnace analysis, diagnosis of the vacuum furnace "disease", to find out the "cause" of its energy-saving technical transformation to further improve the thermal efficiency of the heating furnace, and access to the vacuum furnace operating economy and technology Performance indicators of the parameters of the analysis of the operation of the furnace timely adjustment of the vacuum furnace conditions to achieve the best state of operation, so as to find effective ways and directions to save energy.
Combustion device is the heart of the furnace part of its work directly affects the amount of energy consumption. At present, the domestic burners successfully applied in the vacuum furnace are adjustable flame burner, flat flame burner, high-speed nozzle, its own preheating burner, low nitrogen oxide burner, etc.. Recently, it has been developed into a heat storage burner to adapt to the use of gas and diesel fuel to provide a variety of advanced burners. The correct use of high-efficiency advanced burners can generally save energy by more than 5%. Among the more widely used are flat flame burners, high-speed burners and their own preheating burners. Flat flame burners are most suitable for use in heating furnaces, high-speed burners for various types of heat treatment furnaces and vacuum furnaces, their own preheating burners are a combination of burner, heat exchanger, smoke exhaust device as one combustion device for heating melting, heat treatment and other types of vacuum furnaces. In addition, according to the type of fuel to choose a good performance of energy-saving combustion device and with it the matching fan, oil pumps, valves and thermal detection and automatic control system to ensure good combustion conditions and control and adjustment function is also a proven energy-saving measures. Conventional energy-saving combustion technologies are high-temperature air combustion technology, oxygen-rich combustion technology, heavy oil emulsification technology, blast furnace oxygen-rich pulverized coal spray technology, ordinary furnace fuel into the furnace before the magnetization treatment technology. The application of these technologies in the vacuum furnace has achieved certain energy-saving effect. Among them, the widely used high-temperature air combustion technology and oxygen-rich combustion technology.
The design or improvement of the furnace should be based on the production requirements as far as possible to choose the appropriate furnace structure and new energy-saving materials to improve the degree of mechanization and energy utilization. At present, the measures usually used are
1, the use of round hearth instead of box-shaped hearth can strengthen the effect of uniform heat transfer from the hearth to the workpiece by using a reasonable hearth space and increase the heat exchange surface between the workpiece without increasing the volume of the hearth space, thereby improving thermal efficiency. Due to the use of circular furnace body to reduce the outer wall area of the furnace and thus reduce the heat loss of the furnace wall accordingly.
2, the use of high-speed burner or set up a fan in the furnace chamber to strengthen the convective heat transfer in the furnace. Especially small heating furnace high-speed airflow can destroy stagnant in the surface of the workpiece to prevent heat transfer and interface reaction furnace gas boundary bottom layer to play a role in shortening the heating time and speed up the role of increasing the temperature of the workpiece.
3, the furnace body sealing including the furnace chamber in the lead-in components furnace shell furnace door and other places of sealing. The emergence of refractory fiber products for the solution of the furnace sealing has created the conditions for the realization of soft sealing.
4, the use of new furnace with energy-saving refractory materials composite furnace, refractory castables cast as a whole heating furnace with high strength, integrity, good airtightness, long life. Ceramic fiber furnace has good gas tightness, low temperature of furnace exterior, and long service life.
5, furnace structure in the premise of ensuring the structural strength and heat resistance of the furnace should try to improve the insulation capacity and reduce the saving heat and heat loss. Choose refractory fiber, rock wool, etc. as the insulation layer, with lightweight bricks as the lining of the furnace body to reduce the heat storage loss of the furnace body, in enhancing the thermal insulation and heat preservation of the furnace while reducing the heat loss of the furnace wall.
6、Coating high temperature high radiation coating on the inner wall of the furnace body to strengthen the radiation heat transfer in the furnace, which helps the full utilization of heat energy its energy saving effect is 3%-5%.