How to operate the device for furnace drying?

Key points for the furnace operator: 1. Function of equipment and facilities – Primary air duct: It serves to assist in combustion; the heat generated by gas combustion increases the volume of primary air. Under conditions of complete combustion, the temperature in the furnace decreases, while incomplete combustion results in black smoke and an increase in temperature. During ignition, all primary air valves are closed; after ignition, the degree to which the primary air flow is increased is determined based on the combustion efficiency and the furnace temperature. Secondary air duct: The air remaining after the main air enters the primary air flows into the secondary air duct, which serves to cool the furnace wall temperature and improve heat utilization efficiency. Ignition gas line: Used for ignition; once ignition is completed, it switches to the annular burner, at which point the ignition gas line is deactivated. It is accompanied by an ignition compressed air line. Ring burner: Used for heating and maintaining a constant temperature; the associated valve is usually a globe valve, which is easy to close, but offers a large range of adjustment – it is therefore advisable to use a fine-tuning valve for operation. Air damper: blade-shaped. For ignition use: close the air valve before lighting to prevent the small flame from being blown out; after ignition, increase the gas supply slightly before opening the air valve fully. Gas generator: a pressure vessel, with safety accessories such as pressure gauges, level gauges, and safety valves. Liquid hydrocarbons are collected and heated with steam to produce gas; the system includes a flow path for liquid hydrocarbons from the secondary unit to the generator as well as a steam heating system. In theory, automatic control of liquid level and pressure is possible, and the generated gas is sent to the furnace. Flame arrester: It prevents flames from spreading back into the gas pipeline; therefore, the bypass valve is generally not opened. 2. Control after ignition – Gas pressure control: Range of control: 0.20~0.35 MPa (gauge); the pressure should be adjusted to a lower level at low temperatures. At present, control can only be achieved through the auxiliary line of the steam heating control valve; this valve is a globe valve and should be adjusted in small increments. Operation is carried out using an F wrench for gentle turning – no forceful twisting should be applied, unless there is a rapid drop in gas pressure, in which case slight forceful turning may be used, but the pressure should be gradually adjusted back up again to prevent sudden increases in pressure. Gas flow control: Redirect the flow from the top of the gas generator to in front of the furnace. After ignition, the annular burner is put into use; first, the gas flow rate is adjusted using a DN40 valve, and then it is gradually switched to control via a DN80 valve, with no other valves being used to adjust the gas flow rate. Both of these manual valves are globe valves, intended solely for fine tuning. They are operated using an F wrench; no significant twisting motion is allowed, unless there is severe overheating or a rapid drop in gas pressure (or a rapid drop in furnace temperature), in which case slight rotation of the valve is permitted. Furnace temperature control: Control range: 600~850°C. During the low-temperature phase, if the regeneration temperature is below 320°C, the temperature can be set slightly lower; otherwise, a higher control level should be applied. During the constant temperature phase, the furnace operators control the process by aiming for a suitable furnace temperature value; they mainly adjust the gas pressure to stabilize this temperature, and generally do not adjust the opening degree of the gas valves. At this time, neither the primary air nor the secondary air needs to be adjusted. During the temperature-raising phase, maintain stable gas pressure, open the gas valve wider, and monitor the furnace temperature. If the furnace temperature is high (e.g., above 800°C), increase the amount of primary air; once the primary air flow is at its maximum, reduce the amount of secondary air. If there is too little secondary air (e.g., below 15% of the maximum flow), it is possible to slightly increase the main air flow. During the cooling phase, increase the amount of secondary air; if the secondary air is at full capacity, reduce the amount of primary air. Once the furnace temperature rises, lower the gas valve. If a rapid shutdown of the furnace is required, the gas valves can be closed directly. Shutting down the furnace: Once it is necessary to stop the furnace, the gas valves in front of the furnace can be closed directly to cease the collection of liquid hydrocarbons and heating, while the primary and secondary air valves are opened. Control of liquid carryover in gas: If too much heating steam is introduced, the gas pressure increases and the temperature of the gas rises. As pressure and temperature drop along the back section along with heat dissipation, the gas re-condenses into liquid hydrocarbons. When liquid is carried over in the gas, pressure fluctuations occur ahead of the furnace, and the furnace temperature soars; in severe cases, this can lead to damage to the internal components of the furnace. Key points for preventing liquid carryover: The gas pressure must not exceed 0.35 MPa (gauge), and the amount of heating steam introduced must be strictly controlled. In winter, heat is applied using a rubber hose to supply a small amount of steam at the flame arrester in front of the furnace. Once liquid is present, reduce the valves for heating steam and gas to prevent the furnace temperature from rising any further. When the furnace temperature drops, adjust the gas flow and heating steam accordingly to keep all relevant parameters at reasonable levels. Water cutting: Generally, after cleaning the line and filling the gas generator with gas, water cutting should be intensified. Generally, water needs to be shut off before starting the furnace after a major repair, including in the pipelines. For minor repairs, such as gas generators and gas lines that have not been purged, it is not necessary to cut off the water supply. 3. Responsibilities of the boiler operator: During shift handover, the person handing over the shift must adjust all parameters of the auxiliary combustion chamber to reasonable and stable levels before handing them over to the successor. They must also convey the operational parameters, control settings (such as valve openings), tools, and relevant instructions. Since boiler operation is not part of daily tasks, operators have little opportunity to gain experience; therefore, the person handing over the shift must provide guidance for 20 minutes to help the successor get up to speed before the handover can be completed. When taking over, the successor should ask relevant questions, familiarize themselves with the site, and monitor the furnace temperature and gas pressure in front of the furnace for a period of time to confirm that they are within normal and stable ranges before completing the handover; only then can the person handing over leave the site. The boiler operators should strictly control the gas pressure, carefully adjust the gas flow rate, maintain close communication with the personnel inside the room, stay focused, and take strict precautions to prevent overheating and flameout. This post was last edited by xdw0418 on 2009-2-18 23:14.]

Generally, there is a strict heating curve for furnace drying: 110 degrees to remove moisture, 150 degrees to remove surface water, 350 degrees to remove crystalline water, 500 degrees for sintering, etc. The numbers aren’t entirely accurate, but the idea is similar; it usually takes 5 to 6 days