General purposes and steps of heating a furnace

Purpose of oven drying: to dry the oven walls and remove surface water and crystalline water. High-temperature baking also has a sintering effect.

I. Initial Operation 1. During the entire heating process of the heat transfer oil boiler, it is necessary to ensure normal circulation of the heat transfer oil. The temperature increase rate of the heat transfer oil should be strictly controlled within 10–20°C per hour, and its maximum temperature must not exceed 100°C. 2. After the furnace has been properly dried. When the temperature of the heat transfer oil exceeds 100°C, the residual water in the piping system and the low-volatility components in the heat transfer oil begin to vaporize. As the temperature rises, the vaporization rate of water and low-volatility components in the heat transfer oil increases significantly; therefore, the temperature increase during the dehydration and venting process should be strictly controlled to within 3–5°C per minute. Under normal conditions, the exhaust volume is highest when the heat transfer oil is heated to 105–130°C. 3. Once the pressure of the heat transfer oil circulation pump is stable and no gas is discharged from the high-level tank, the heating rate of the heat transfer oil can be controlled to be within 10–20°C per hour, thereby achieving the desired operating conditions.

Purpose: The purpose of drying the furnace is to slowly remove the moisture accumulated in the furnace walls during construction, and to ensure thorough sintering of the refractory mortar. If this moisture is not removed, as the furnace temperature rises rapidly at the start of operation, this moisture will evaporate quickly, causing the brick joints to expand and cracks to form; in severe cases, this can lead to the collapse of the furnace walls. Steps: (1) Before heating the furnace, all manholes, viewing doors, explosion-proof doors should be opened, and the chimney baffles removed to allow natural ventilation for more than 5 days, after which ignition to heat the furnace can begin. (2) At the start of furnace drying, open the chimney damper by about 1/3; once the temperature inside the furnace rises and the suction force increases, then open the chimney damper further. (3) Steam is introduced into the furnace tube to start heating it; once the temperature inside the furnace reaches 130°C, the burner can be ignited to continue with the drying process. (4) When heating the furnace, gas fuel should be used as much as possible, and the burners should be ignited diagonally. (5) During the furnace drying process, the temperature rises evenly; the rates of heating and cooling should follow the designated drying curve, and the condition of the furnace walls should be monitored regularly. (6) Records should be kept during the furnace drying process, and the actual drying curve should be drawn after drying. (7) The furnace chamber is cooled at a rate of 20°C per hour. When the furnace temperature drops to 250°C, shut down the furnace and let it cool; when it drops to 100°C, enable natural ventilation. (8) After the furnace is dried, a thorough inspection of the furnace should be carried out; any defects found should be addressed. Liners with crack widths greater than 3 mm and depths exceeding 5 mm should be repaired, while those with voids or separation from the steel plate must be thoroughly repaired.