Gas furnace preheater and control system

10. Preheater
The GC type shell and tube insert spoiler heat exchanger is used to increase the preheating temperature of the air. When the furnace temperature is 1000℃, the air temperature is preheated to 300-350℃.
The GC type high-efficiency insert heat exchanger has a lower air side pressure loss than the general insert heat exchanger under the same heat transfer coefficient, and its value is about 1500Pa, thus reducing power consumption.
When the flue gas temperature is 600℃, the comprehensive heat transfer coefficient is above 45W/M2℃, and when the flue gas temperature is ≥900℃, the comprehensive heat transfer coefficient is above 55 W/M2℃.
The heat exchanger is designed with heat-resistant steel and stainless steel according to different temperatures, and the layout adopts temperature uniformization and thermal stress elimination measures.
11. Control system
The system mainly adjusts and controls the flow of the gas pipeline of each furnace, the flow of flue gas and the dilution air volume through the detection of the temperature and pressure of the furnace, and is equipped with a natural gas main quick cut-off device.
The furnace pressure has a great influence on the use effect of the heating furnace. When the furnace pressure is high, the furnace gas will rush out of the sealing gaps of the furnace body to form airflow scouring, which has a great impact on the furnace door and furnace bottom sealed with fiber materials. At the same time, the high-temperature airflow will also affect the surrounding environment and control devices of the furnace body. When the furnace pressure is low, cold air is sucked in from the sealing gap, which not only increases the oxidation of the workpiece, but also causes the high temperature in the furnace to be quickly drawn out by negative pressure, resulting in fuel waste. For this reason, the furnace pressure measuring point is installed on the exhaust duct to control the electric regulating flue gas valve to keep the furnace pressure in a slightly positive pressure state. The furnace adopts zoned furnace temperature control. Each zone is equipped with a thermocouple to measure the temperature and enter the multi-point recorder to centrally track and record the temperature in the furnace. 12. Safety interlocking system The safety interlocking of the trolley and the furnace door. When the furnace door is not opened to a certain position, the trolley will be locked in and out. When the trolley seal is not opened, the trolley will be locked in and out. When the air, gas pressure, and compressed air pressure do not meet the specified requirements, the combustion of the burner will not be started. If it is burning, it will be safely closed.