Thermal management during furnace drying
Thread Content
Controlling the air excess factor during furnace drying is very important. At the beginning of the drying process, to prevent water vapor from condensing in the small flues, a higher air excess factor should be maintained in order to increase the volume of waste gas and reduce the temperature difference between the upper and lower parts of the furnace. In addition to appropriately increasing the suction force in the flues, it is essential to open the secondary air valves wider. After the drying period ends, the secondary air damper gradually closes, the air excess coefficient gradually decreases, and as the amount of fuel increases, the furnace temperature rises gradually, along with an increasing temperature difference between the upper and lower parts of the furnace. The air excess coefficient is measured by taking samples from the top of the vertical flue and the grate bricks; if there is a large difference between the two values, it indicates that the surface of the furnace is not airtight, and the issue should be identified and sealed promptly. If the temperature in the combustion chamber rises while the temperature in the small flue remains unchanged or decreases, the air excess factor should be increased ； If the combustion chamber temperature drops, the coefficient should be reduced ； If the temperatures in both the combustion chamber and the small flue do not reach the required levels, the air excess factor should be maintained while increasing the fuel amount.
If the oven is heated with a door but lacks a secondary air damper, how should it be adjusted? What should be the reasonable design for such a damper?
Oven drying with a door also has secondary air dampers; facing the burner, the one closer to one’s self is the primary air damper, while the one further away is the secondary air damper.
When heating the furnace, the properties of silica bricks should be fully considered to ensure proper operation and extend their lifespan. After heating the coke oven, the expansion in the carbonization chamber area is nearly 200 millimeters. The daily expansion rate of the drying furnace is generally set at no more than 0.035%, with a drying period of 50 to 60 days. Due to the significant expansion that occurs during the heating up of coke ovens, certain equipment and structures connected to the oven body must be connected, fixed, and sealed only at the end of this process, once the expansion of the oven body has essentially ceased.