Test plan for heat transfer oil furnace and precautions

The commissioning plan for a heat transfer oil furnace should be formulated in accordance with relevant regulations, and generally should include the following contents； 1. Operational process parameters and key specifications of organic heat carriers. 2. Checks and preparations before lighting the fire. (1) List the inspection items one by one. This includes the sealing condition, whether there are any cracks, leaks, or deformations in the pressure-bearing components, whether the insulation layer is intact, whether the burner, grate, and their associated gearboxes are functioning properly, whether the opening positions of all relevant valves are correct, and whether all safety devices, instruments, and automatic control systems meet the specified requirements. (2) It clearly specifies the preparatory work to be done before ignition, which mainly includes preparing the heat transfer fluid, fuel, igniter, and cooling water, as well as conducting a cold cycle test of the system and checking for any contaminants in the filters. 3. Ignition: Based on the characteristics of the combustion equipment in organic heat carrier boilers, the key operational steps from ventilation to normal operation are clearly specified, including ventilation, ignition, temperature rise, dehydration, exhaust (of vapor), replenishment of the heat carrier, and inspection of the automatic control system. 4. Oven drying and cleaning: Oven drying should be carried out for organic heat carrier ovens that have undergone major repairs to their furnace walls or have been newly installed, in order to remove moisture from within the furnace walls. Organic heat carrier boilers that have undergone major repairs to their heating surfaces and main piping systems, or those that are newly installed, should be cleaned to remove impurities such as oil and rust. Formulate procedures and qualification standards for furnace drying and cleaning in accordance with relevant regulations and actual conditions; the main contents should include ； The opening positions of valves before furnace heating, as well as the control of combustion, temperature, speed, and time during furnace heating. Requirements for furnace cleaning solutions, temperature control, filter cleaning, system drying, etc., as well as the acceptance criteria for furnace drying and cleaning. 5. Operation management: Clearly specify the main adjustment methods for control parameters such as temperature, pressure, liquid level, and combustion once the heat carrier furnace is in normal operation; outline the inspection and maintenance procedures for pressure gauges, thermometers, and level gauges during operation; and define the key operational points for tasks such as waste discharge, steam release, and slag removal. 6. Shutdown of the furnace (1) Clarify the procedures for shutting down the furnace ； This includes the requirements for combustion, forced and induced ventilation, temperature, liquid discharge, etc., during normal shutdown processes. (2) Emergency shutdown of the furnace usually occurs in cases of fire, pipe rupture, severe deformation of pressure components, power outage, overpressure, overheating, severe damage to combustion equipment, shutdown of the circulation pump, and issues related to the handling of heat transfer fluids. Heat transfer oil furnace – Shutdown procedures (I): Normal shutdown. Temporary shutdown, with the procedure varying depending on the duration of the shutdown. 1) For temporary shutdowns (short-term stops), use a small amount of wet coal to keep the fire alive on the manual furnace grate, then open the furnace door, turn off the blower and chimney dampers, and maintain the remaining fire in the furnace chamber ； The chain grate continues to push coal into the furnace for 5–10 minutes, or until it has moved about 400 millimeters inward, after which the blower and exhaust fan are turned off, as well as the chimney damper, in order to maintain the temperature inside the furnace. Keep the circulation pump running, use thermal equipment to activate the bypass, and maintain normal circulation of the heat transfer fluid to prevent localized overheating. When heating is continued with the heating equipment, use a hand-held furnace rake to stir the fire, close the furnace door, turn on the blower and the chimney damper to restore combustion. For chain grates, the flue dampers and exhaust fans are turned on first, followed by the blower, in order to raise the temperature inside the furnace. Once the temperature at the front arch rises, the grate is activated to resume combustion. 2) Prolonged shutdown of the furnace (usually over 8 hours): When a shutdown of more than 8 hours is required, in the case of a manually operated grate furnace with a small furnace chamber, after turning off the fans and flue dampers, thicker wet coal must be used to keep the fire alive. Someone must be on duty during the shutdown period to ensure that the fire does not go out. If the wet coal catches fire spontaneously, more wet coal must be placed on top of it. For chain grates, after stopping the blowers and induced draft fans, thicken the coal layer and advance it 800~1200 millimeters into the grate. In winter, when temperatures are low and the furnace cools down too quickly, it is advisable to turn on the blower and exhaust fan for a short period during shutdown to ignite the coal, and then add some new coal – the flame must not be allowed to go out. The circulation pump continues to operate during shutdown, circulating the oil; a bypass is opened when the heat-using equipment is not in use. When the temperature of the outlet oil drops below 100°C, turn off the circulation pump. When restarting with thermal equipment, the heat transfer oil furnace should first start the circulation pump to get the heat transfer fluid flowing, and then initiate combustion again. If the oil temperature has dropped below 100°C before restarting, combustion cannot be resumed as quickly as in the case of a short-term shutdown; instead, the rate of temperature increase must be controlled to prevent localized overheating. II. Operations for shutting down the furnace for maintenance (shutting off the fire) (1) Normal sequence for shutting down a manually fired grate furnace: a) Gradually reduce the load, decrease the amount of coal supplied and the air flow; once the load is brought to zero, stop supplying coal and air, and then stop the exhaust air flow. b) Close the furnace door, ash door, and flue dampers to prevent rapid cooling of the boiler. c) When the pressure gauge of the furnace reaches zero and the temperature of the heat transfer fluid drops below 150°C, open the furnace door, ash door, and flue dampers to enhance natural ventilation for cooling. d) The heat transfer fluid inside the boiler is transferred to the oil storage tank, insulation measures are taken for the boiler’s heating pipes, etc.; thereafter, the inspection hole is opened and flushed with steam to remove carbon deposits and impurities. (2) Normal shutdown procedure for chain grate stoves: a) Close the crescent-shaped baffle under the coal hopper, and lower the coal gate to 30–50 millimeters, which facilitates air circulation and prevents damage to the gate. b) Reduce the grate speed and decrease the blast air and exhaust air flow; once the coal on the grate has been almost completely burned, stop the blast air and exhaust air supply. c) Continue rotating the grate to remove all ash and slag. d) Once the pressure inside the furnace drops to zero and the temperature of the heat transfer fluid falls below 70°C, the heat transfer fluid in the furnace is transferred to the oil storage tank. The furnace is properly isolated from other furnaces and pipelines, after which the inspection hole is opened and steam is used to flush out any burnt residue or impurities. The normal shutdown procedure for a briquette furnace is relatively simple: stop feeding coal, close the smoke dampers, reduce combustion until the fire is extinguished. Safety Precautions (1) The media inside the heat transfer oil furnace are all flammable substances that are highly heated and highly permeable. The boiler operators must wear protective equipment in the control center. When opening and closing valves, do so gently and slowly; avoid having your head directly above the valve disc to prevent hot fluid from escaping through the gap between the valve stem and the packing and causing burns. (2) The heat transfer fluid is lost during operation, so it is necessary to top it up in a timely manner. In a system that is operating at high temperature, cold medium that has not been dehydrated cannot be added directly. (3) The liquid-phase furnace relies on a circulation pump for forced circulation; in the event of a power outage (the circulation pump stops operating), measures must be taken promptly to prevent the heat transfer fluid inside the furnace from overheating due to the cessation of circulation. If there is no external power source available and the backup pump cannot be started immediately, the grate should be stopped right away, and the valve connecting the expander to the furnace body should be opened to allow the cold oil in the expander to flow into the furnace, thereby maintaining oil circulation within the furnace. Until the furnace temperature drops below 300°C and the hot oil outlet temperature falls below 100°C. If conditions permit, a circulating pump powered by a standby diesel engine can also be added. (4) Sufficient fire-fighting equipment should be available in the boiler room, and the fire extinguishing devices must be regularly inspected to ensure they are in good condition. This post was last edited by lyhh9024 on 2009-3-29 20:35.]