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Maintenance of the heating furnace lining: The lining of direct crude oil heating furnaces is made of aluminum silicate refractory fiber folded blocks, which offer good elasticity, a low thermal conductivity, and excellent insulation properties. The drawback is that the furnace lining support at the top of the radiation chamber and convection chamber is not secure. If not maintained properly, the lining pins are prone to corrosion, causing the lining to fall off. The daily maintenance of heating furnaces should focus on smooth operation. Prevent blowout during staged shutdown. The heating and cooling processes must be carried out in accordance with the heating furnace’s temperature rise curve to prevent too rapid temperature increases. The large temperature fluctuations in the heating furnace cause deformation and cracking of the furnace lining, leading to its detachment and thereby increasing heat loss from the furnace body. The viewing ports, manholes of the heating furnace, as well as the furnace lining around the burner bricks are exposed to the impact of hot and cold air currents. It is easily weathered and damaged. The maintenance method involves cleaning, organizing, and shaping the damaged furnace lining at each opening, and then applying a high-temperature adhesive protective layer. The furnace lining surrounding the burner bricks is prone to damage due to frequent maintenance and coking removal of the burner; severe damage can cause the front wall of the furnace to overheat and the steel plates in that wall to deform. As a result of these deformations, the axis of the entire burner may become misaligned with the axis of the furnace’s radiation chamber, leading to uneven burning. The only way to correct this issue is by replacing the steel plates in the front wall of the furnace. Therefore, during burner maintenance and the process of cleaning coke from the burner bricks, it is necessary to avoid damaging the furnace lining. Once the lining is damaged, the damaged area must be cleaned, covered with refractory ceramic fiber mat, secured with iron nails, and then coated with high-temperature adhesive twice more. The joint between the fire-resistant ceramic fiber mat and the original furnace lining must be properly treated, with high-temperature adhesive used to fill that joint. It is necessary to regularly maintain the seals of the viewing ports, manholes, and explosion-proof doors to prevent them from becoming loose or falling, to ensure good airtightness, reduce heat loss, and improve the thermal efficiency of the heating furnace. Manual ash cleaning and mechanical soot blowing in heating furnaces: After operating for a certain period of time, a layer of carbon ash and oil coke accumulates on the furnace tubes; this accumulation of ash increases thermal resistance and reduces the heating efficiency of the furnace. Therefore, it is necessary to carry out proper ash cleaning of the heating furnace: manual ash cleaning of the radiation chamber should be done twice a month, while the dust accumulated on the furnace tubes should be removed using compressed air and soft brushes. The oil coke on the furnace tubes should be removed using copper tools; shovels or other hard metallic objects must not be used to avoid damaging the surface of the furnace tubes. Mechanical soot blowing in the convection chamber is carried out at regular intervals according to the soot blowing schedule. Strengthen the maintenance of the soot blowing system to ensure that no areas are left untreated, thereby preventing ash accumulation on the convection tubes. Soot blowing is best carried out while the heating furnace is in operation, with the flue dampers fully open; this achieves the best results in removing accumulated soot, lowering the exhaust gas temperature, and improving the heat exchange efficiency. When the backup heating furnace is out of service for an extended period, the temperature inside the furnace drops. When it falls below the dew point temperature, water vapor combines with sulfur dioxide, sulfur trioxide, or carbon dioxide present in the dust to corrode the tube walls, accelerating their oxidation and peeling. Therefore, all openings on the shut-down heating furnace must be tightly sealed. Multiple heating furnaces need to operate in turn on a intermittent basis, with the furnace temperature being maintained above the dew point temperature to prevent corrosion of the furnace tubes. Adjustment of the heating furnace’s operating conditions: This is a highly delicate task, and attention should be paid to the following aspects. It is necessary to control the amount of flue gas discharged and the oxygen content in that gas. The higher the oxygen content in the flue gas, the greater the amount of flue gas discharged, and thus the greater the heat loss. The heat lost through the discharged flue gas accounts for generally 15% to 25% of the total heat, and this constitutes the main portion of the heat losses in heating furnaces. The measures to control this portion of heat loss involve ensuring optimal atomization and complete combustion in the furnace burner, adjusting appropriately the opening of the flue dampers as well as the oil-to-air ratio in the burner. Depending on the load of the furnace, along with changes in local season and ambient temperature, it is necessary to control the negative pressure inside the furnace and reduce the oxygen content in the flue gases, thereby preventing excessive air from entering the furnace. For every 10% reduction in the oxygen content of the flue gases, the thermal efficiency increases by about 1.3%. Strengthen equipment management to maintain the integrity of the furnace, ensure tight sealing, and reduce heat loss. According to relevant data, in a fuel oil heating furnace operating at a rate of 0.5 tons per hour, by sealing all openings and blocking the air gaps in the structure, the amount of fuel oil used can be reduced by 1.1%. 132 kilograms of fuel oil are saved per day. By making fine adjustments to the heating furnace and mastering the basic aspects of its maintenance, it is possible to ensure its good condition, extend its service life, and improve its thermal efficiency.