Operation and precautions for heat transfer oil furnaces

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Operation and precautions for heat transfer oil furnaces 1. Heat transfer oil circulation process: Ensure that the valves in the system outside the heat transfer oil furnace are properly opened； The inlet and outlet valves of the heat transfer oil furnace are opened ； The inlet valve of the hot oil circulation pump is opened; the inlet valve is closed ； Start the circulation pump on the public control panel; immediately after it starts, open the outlet valve of the hot oil circulation pump such that the pressure at the pump’s outlet remains between 0.8 and 0.95 MPa. Note: When starting the hot oil circulation pump, close the outlet valve first and then open it ； The outlet pressure cannot be too low. 2. Fuel oil flow path: The valves and equipment in the external system of the diesel pump on the crude oil processing skid are in proper condition ； Open valves 6.11, 6.122, 6.1611, and 6.1612 on the crude oil treatment skid ； Set the double union ball valve in front of the burner to the diesel position ； Check and confirm that the pressure before the diesel pump on the crude oil treatment skid is between 0.1 and 0.15 MPa ； Start the diesel pump on-site at the crude oil treatment skid ； Note: The outlet pressure of the diesel pump is between 0.1 and 0.2 MPa. 3. Starting the furnace: On the furnace control panel, first press the alarm unlock button “UNLOCK”, then press the furnace start button “BURNER ON”” ； When all the alarm conditions are met, the heating furnace automatically completes the startup process without the need for any intervention ； 1) Conditions required before starting the furnace: The level in the expansion tank is normal, the flow rate of hot oil is sufficient, the diesel pressure is not high (crude oil pressure is not high), the temperature of the coils is not high, the exhaust gas temperature is not high, and the burner door is closed ； The burner cannot be started when the above conditions are not met ； 2) After pressing the burner start button “BURNER ON”, the heating furnace automatically carries out the startup procedures: a. Start the fan: The fan should begin operating immediately after pressing the start button ； Starting 14 seconds after the fan begins to operate, the primary and secondary air pressures are monitored until the fan stops; if no pressure is detected, a fault alarm is triggered (low low primary and secondary air pressure) and the fan shuts down. b. Open the damper fully: After the fan starts operating, the damper is gradually opened to the purging position (the purging limit switch closes) ； The damper should be opened to the purge position after 45 seconds; otherwise, a fault alarm will be triggered (failure to reach the purge position) ； The fan stops operating when this fault occurs. c. Pre-purge: When the damper reaches the purge position, it stops there, and the fan performs purging for 60 seconds ； At this time, the burner oil pump and the spin drum motor should be running. d. Closing the air valve: After 60 seconds of purging, the air valve begins to close; it closes until it reaches the ignition position (at which point the ignition position limit switch closes). If no signal indicating that the ignition position limit switch has closed is detected within 45 seconds after the air valve starts closing, a fault alarm is triggered (indicating that the ignition position has not been reached), and the machine shuts down due to the fault. e. Sparking by the sparking electrode: The sparking electrode generates a spark when the air damper is adjusted to the ignition position ； Spark electrode sparks for 8 seconds ； f. Ignition solenoid valve opens and ignition fuel pump starts: 16 seconds after the ignition electrode generates a spark, the ignition electrode and the ignition fuel pump come online ； g. Flame detection: A flame signal must be detected within 4 seconds of the ignition solenoid opening; otherwise, a flame fault is triggered and the machine stops. h. Open the main solenoid valve: The main solenoid valve opens 6 seconds after the ignition valve opens ； i. System operation: The system enters normal operation 15 seconds after the main fire valve is activated ； Only at this point can the system load be adjusted. 4. Load adjustment: 1) Manual adjustment: Adjust manually on the temperature controller of the furnace control panel. Press the manual adjustment button; when the manual indicator light comes on, use the up and down keys to set the fuel supply level between 0 and 100 (corresponding to 0–100%). 2) Automatic adjustment: It is carried out automatically via the temperature controller on the furnace control panel. When the manual button is pressed and the manual indicator light goes out, the system enters automatic adjustment mode; the temperature controller automatically adjusts the damper and oil supply volume according to the set value to maintain a stable temperature. The operator can modify the set values according to the process requirements. The specific procedure is as follows: use the up and down buttons (to increase or decrease the set values) and observe the data in the lower window; this data represents the current set value. A few seconds after the change is made, the new value is automatically reflected in the instrument. The set value is displayed in the middle window. 5. Shutting down the furnace: Manual shutdown – When it is necessary to shut down the furnace, press the button “BURNER OFF”, and the heating furnace will automatically carry out the shutdown procedures. Automatic shutdown: The heating furnace shuts down automatically when a shutdown alarm is triggered. Alarm conditions for shutdown include: extremely low level in the expansion tank, extremely high coil temperature, extremely high flue gas temperature, extremely low flow rate of the heat transfer oil, low pressure of the primary air supply to the burner, low pressure of the secondary air supply to the burner, flame fault, burner door not closed, and low crude oil temperature. Note: Possible fault during dehydration: extremely low heat medium flow rate. This fault is normal, as the volume of water in the system changes drastically when the temperature rises, resulting in unstable system pressure. At this time, it is important to monitor the pressures at the inlet and outlet of the heating furnace, ensuring that the pressure difference remains around 0.2 MPa. 6. Precautions during the dehydration process: 1) Ensure that the expansion tank is connected in series in the system: that is, ensure that the heat transfer oil flows through the expansion tank to facilitate the removal of water. Pay attention to ensure that the valves at the inlet and outlet of the expansion tank in the heat transfer oil system are in the correct position. 2) Pay attention to the outlet pressure of the hot oil circulation pump: the outlet pressure may fluctuate when moisture is present. If the fluctuations are severe or cavitation occurs, it is necessary to reduce the flame in the heating furnace or shut down the furnace; if needed, the pump should also be stopped. 3) Temperature control during dehydration: During dehydration, the focus is on controlling the inlet temperature of the heating furnace, with the temperature maintained between 95 and 105. Also pay attention to the steam coming out of the expansion tank; when the steam output is high, adjust the flame size to stabilize it, and if necessary, shut down the furnace to prevent the tank from overfilling (with the heat transfer oil escaping from the expansion tank). Suggestion: Assign a dedicated person to monitor the level in the expansion tank ； The expansion tank level should be between 1/3 and 1/2. 4) Heat units: Ensure that heat transfer oil flows through all the heat-using units. Regarding pump shutdown: The hot oil circulation pump may be shut down only 1 hour after the heating furnace is stopped and when the furnace temperature drops below 100 degrees Celsius (subject to the more stringent conditions). In the event of a power outage, the furnace should be shut down 1 hour in advance of the outage ； Never stop the pump while the heating furnace is operating normally. When power is restored, the hot oil circulation pump should be started first to restore the heat transfer oil system. This post was last edited by 771207 on 2007-12-25 15:08.]