Here is the correct procedure for drying out a silica brick hot blast stove!

Objectives of Furnace Baking
(1) To slowly drive out moisture from the hot blast stove's masonry, thereby preventing damage to the refractory materials caused by the sudden, massive evaporation of moisture resulting from rapid temperature fluctuations; and to ensure that the refractory bricks undergo uniform, gradual, and complete thermal expansion, thereby avoiding damage to the masonry—such as that caused by concentrated thermal stresses or lattice transformations—and extending its service life.
(2) To enable the checker bricks within the hot blast stove's regenerator chamber to accumulate a sufficient amount of heat, ensuring that, once placed into operation, the stove can supply the blast furnace with high-temperature blast air.

Principles for Drying-out Silica Brick Hot Blast Stoves
(1) During the hot blast stove drying-out process, the temperatures at the left and right arch flanks shall serve as the primary reference for temperature elevation, while simultaneously monitoring the waste gas temperature and the temperature at the silica brick interfaces.
(2) Given the significant variations in the properties of refractory materials, the drying-out process must strictly adhere to the prescribed drying-out curve. By regulating the flow rates of fuel gas and combustion air, the actual temperature curve at the stove dome should be maintained as close as possible to the corresponding target values ​​specified in the drying-out curve. When the dome temperature is within the range of 100–700°C, the temperature deviation shall be controlled within ±2°C; when the dome temperature exceeds 700°C, the deviation shall be controlled within ±3°C.
(3) The drying-out process must proceed continuously without interruption. If, for any reason, normal drying-out cannot be maintained, the stove must be placed in a "holding" (temperature-maintenance) mode.
(4) During the drying-out process, close attention must be paid to controlling the flue gas temperature to prevent it from rising too rapidly due to improper control; such rapid escalation could hinder the ability to maintain the high-temperature zone at the stove top within the specific temperature parameters required by the drying-out schedule.
(5) Upon completion of the drying-out process, the drying-out access ports shall be sealed, and blast furnace gas shall be introduced through the burners to commence normal stove operation. The transition process for switching to blast furnace gas should be executed promptly; specifically, the temperature at the arch flanks must not fall below 900°C at the moment blast furnace gas is introduced.

Pre-Baking Preparations
(1) The hot blast stove masonry work is complete and has passed quality acceptance standards; the site has been cleared and tidied, and all safety facilities have been fully restored.
(2) All instrumentation is functioning accurately, and the cooling system's water pressure and flow rates are normal.
(3) Prior to baking the No. 3 hot blast stove, the hydraulic and electrical systems for all valves have been commissioned; a linkage test run has been conducted, and the systems are ready for both manual and automatic operation.
(4) The mixed gas pipelines and valves designated for the furnace have been fully installed and commissioned, ensuring flexible operation; the mixed gas and compressed air lines have been routed to the immediate vicinity of the hot blast stove's baking access port valve (the mixed gas pipeline has undergone pressure testing for leaks, and the goggle valve has been pre-commissioned).
(5) Two layers of clay checker bricks shall be laid in a circular pattern directly in front of the main wall at the baking access port, positioned 2,000 mm away; each layer covers an area of ​​approximately 8 m². A fire baffle wall, 800 mm in height, shall be erected in front of the checker bricks. A 2 mm thick steel plate shall be laid over the surface of the clay checker bricks, with 10 mm diameter holes uniformly drilled into the plate at 150 mm intervals.
(6) Two baking burners shall be fabricated and inserted into the combustion chamber through the access ports located on the arch side of the furnace; the insertion depth shall be 2,500 mm (measured from the flange face of the access port to the centerline of the burner tip). Additionally, one DN50 mm ignition lance shall be fabricated. The access ports shall be fitted with shielding plates—or blocked using refractory bricks—to prevent excessive air ingress into the hot blast stove; a 50 mm diameter observation port shall be cut into the shielding plate (or left open in the temporary brick wall) to allow for visual monitoring of the flame.
(7) During the initial phase of baking, the blind flange on the exterior of the combustion valve shall remain in place (the blind flange shall be removed—and blast furnace gas introduced for the remainder of the baking process—only after the temperature on the arch side reaches 900°C).
(8) Two temporary thermocouples, designated specifically for the baking process, shall be installed at the interface between the arch side of the hot blast stove and the silica brick lining.
(9) The safety guard walls and shielding plates associated with the cold blast branch pipe, the flue gas branch pipe, and the hot blast outlet shall be removed. (10) Once the conditions for furnace drying are met, open the flue valve, air valve, and air control valve to back-blow Hot Blast Stove No. 3, thereby ensuring unobstructed airflow within the regenerator chamber. Following the back-blowing procedure, close the air valve and air control valve, adjust the flue valve to the specific control position required for furnace drying, and complete all preparatory tasks for the drying process.

Baking Operation for a New Top-Fired Silica Brick Hot Blast Stove
The baking process for the hot blast stove utilizes mixed gas as the combustion medium and compressed air as the combustion-supporting medium; the process is divided into distinct temperature-rising stages, sequenced according to the specific characteristics of the silica bricks.
1) Temperature Control Requirements for Baking
(1) Temperature rise from 20°C to 200°C: 5 days, at a rate of 1.5°C/h; hold at a constant temperature of 200°C for 5 days.
(2) Temperature rise from 200°C to 300°C: 4 days, at a rate of 1.0°C/h; hold at a constant temperature of 300°C for 5 days.
(3) Temperature rise from 300°C to 600°C: 10 days, at a rate of 1.25°C/h; hold at a constant temperature of 600°C for 6 days.
(4) Temperature rise from 600°C to 800°C: 4 days, at a rate of 2°C/h; hold at a constant temperature of 800°C for 2 days.
(5) Temperature rise from 800°C to 1000°C: 1 day; subsequently, switch to normal firing using blast furnace gas to allow the hot blast stove to complete its overall baking process, ensuring the temperature continues to rise evenly until reaching the blast temperature level required by the blast furnace.
(6) The entire baking process shall be conducted in strict accordance with the established baking curve. The gas flow rate must be carefully adjusted based on variations in the dome temperature, with adjustments performed once every 2 to 4 hours.
2) Process Control for Baking Temperatures
The actual duration of the baking process is 39 days. Upon completion of the baking process, the baking access manholes are sealed, and a pressure test is conducted on the hot blast stove; once the test is successfully passed, the hot blast stove is commissioned for production operations.

Precautions for Drying Out Silica Brick Hot Blast Stoves
(1) During the drying-out process, the temperature must be raised in strict accordance with the prescribed drying curve.
(2) Prior to ignition and drying, the hot blast stove's flue valve must be in the open position, while all other valves remain closed. Throughout the drying period, a slight negative pressure (suction) must be maintained within the stove (the opening of the flue valve should be adjusted based on the flue gas temperature and the suction force at the stove top). During the initial stages of ignition, when using a pilot burner to raise the temperature, one flue valve may be fully closed while the opening of the other flue valve is adjusted as needed.
(3) If the pressure in the gas supply network drops to a low level, the central dispatcher must be contacted immediately to ensure a continuous gas supply and prevent any interruption to the stove's drying process.
(4) Operators responsible for the drying process must frequently monitor the combustion status of the gas at the drying burner. Because the refractory materials contain a high moisture content during the initial drying phase, the flue suction force is often weak; this can cause the flame from the mixed-gas burner to become highly unstable and difficult to control, necessitating close observation. In the event of a flameout, the supply of mixed gas and compressed air must be shut off immediately. After waiting 5 to 10 minutes—and only after verifying that any residual gas within the stove has been completely purged—re-ignition may be attempted.
(5) When adjusting the flow rates of gas and air in accordance with the drying curve, avoid making continuous adjustments. The gas flow rate must be adjusted carefully based on the temperature readings at the furnace arch. Adjustments to the gas flow should be made steadily and gradually—rather than abruptly—to prevent excessive fluctuations in temperature control. If the temperature at the arch is too low, the gas flow rate should be increased appropriately; this increase should be implemented in several small increments rather than as a single large step. Conversely, if the temperature at the arch becomes excessively high, the gas flow rate should be reduced appropriately, ensuring that the reduction is not too drastic. With each adjustment, the air-to-gas ratio should be fine-tuned to ensure that the furnace arch reaches its target temperature.

(6) In the event of sudden electrical, mechanical, or other accidents that impact the stove baking process, immediately shut off the gas, air, and other valves on the stove burners. Resume the baking process only after the accident has been resolved.
(7) If the stove temperature reading becomes unreliable due to instrumentation malfunctions, repair the instruments immediately. During this time, maintain constant gas and combustion air flow rates to the stove. Once the instruments are repaired, if the temperature is found to be above or below the planned value, adjust the heating rate to align with the established stove baking curve. If the temperature is below the planned value, extend the baking duration accordingly; if it is above the planned value, hold the temperature constant until the actual time-temperature point coincides with the established baking curve, at which point heating may resume.
(8) Adjust the opening of the flue valve based on the current baking duration and flue gas temperature. Upon completion of the baking process, the waste gas temperature should fall within the range of 100°C < T ≤ 400°C.
(9) Throughout the baking process, continuously monitor and mark the thermal expansion of any newly modified sections of the hot blast stove shell.
(10) Should any significant anomalies arise during the baking process, immediately notify relevant supervisory personnel and take appropriate measures to maintain thermal insulation.
(11) During blast furnace operations, the operators of the other three hot blast stoves must provide advance notice to the on-site stove baking personnel before switching stoves and discharging waste gas. The baking personnel should closely monitor the combustion status of the stove burner during this time. When discharging waste gas, the process must be executed slowly and gradually to prevent flue gas backflow into the stove currently being baked, which could adversely affect the baking process.
(12) When removing blind flanges from the gas branch lines, the blast furnace team must make preparations in advance. After isolating the gas supply, the pipeline must be purged. The gas and oxygen content within the pipeline must be tested; construction personnel may proceed with the work only after the test results are verified as safe (the removal of blind flanges is scheduled to take approximately 6 to 8 hours).