Ask the teacher to provide a checklist for inspecting the burner of a heat transfer oil furnace

This post was last edited by qy576100527 on 2017-7-3 15:11. I. Checks before startup 1. Ensure that the heating furnace and its surrounding area are clean and free of debris; check whether the furnace body, burner, controller, viewing ports, and flue (chimney) are in proper condition； 2. Reverse the process equipment and flow sequence, and check whether the oil level in the expansion tank is above 1/4–1/2 of its capacity, as well as whether thermometers, pressure gauges, etc. are functioning properly ； 3. Turn on the power to the heating furnace control cabinet, check whether the voltage is normal, and verify that the indicator lights and various display instruments are functioning properly ； 4. Adjust the main gas pressure regulator and the secondary pressure regulator so that the pressure is controlled at 0.005 MPa. II. Startup 1. Start the heat transfer oil circulation pump (one in operation and one as backup; follow the operating procedures for water pumps). After starting the pump, allow it to circulate normally for about 0.5 hours to stabilize the pressure ； 2. Press the burner start button and observe whether the flame in the furnace is burning normally; if ignition does not occur, the burner should be started again after the fault has been resolved. III. Shutdown Procedures 1. Normal shutdown ① Gradually reduce the temperature, turn off the burner, and stop combustion ； ②When the temperature of the hot oil drops below 70°C, stop the operation of the hot oil circulation pump (follow the operating procedures for water pumps) ； ③Turn off the main power supply and complete the shift handover records. 2. Emergency shutdown: In the event of an emergency that requires an immediate shutdown of the furnace, the burner should be shut off quickly. At the same time, the burner should be moved away using its hinge axis, so that natural ventilation can occur between the furnace chamber and the chimney. This allows the heat stored in the furnace chamber to dissipate, enabling the heat transfer oil to cool down naturally and preventing overheating. IV. Precautions: During routine inspections, it is necessary to check for any leaks around the heat transfer oil furnace. Sufficient fire-fighting equipment suitable for dealing with oils and electrical devices should be available in the vicinity; water must not be used as a fire extinguishing agent. The safety operating procedures for coal-fired liquid-phase organic heat carrier boilers are outlined as follows: I. Ignition and heating up (1) Prerequisites before starting up the organic heat carrier boiler 1. Complete the registration procedures for the organic heat carrier boiler and obtain a usage registration certificate. After the new boiler is installed, it must pass inspection and approval by the local boiler inspection agency. The user entity shall fill out the \"Boiler Registration Form\" and go to the boiler safety supervision department of the local Quality and Technical Supervision Bureau to complete the registration procedures and obtain a registration certificate for use. Unlicensed furnaces must not be put into operation. 2. Boiler operators must pass assessments conducted by the quality and technical supervision authorities and hold a \"Boiler Operation Certificate for Heat Carrier Boilers.\" In addition to meeting the requirements for industrial boiler operators, they must also receive training in the specific knowledge related to heat carrier boilers. 3. The user unit shall have sound management systems and safety operating procedures. (II) Preparations before ignition 1. Inspection and preparation of the inside and outside of the organic heat carrier furnace, including: draining any remaining water from inside the furnace and drying it out ； All debris in the furnace has been removed ； All inspection holes, manholes, etc. have been sealed, and the packing used meets the requirements for the medium in heat carrier furnaces. Inspection of safety accessories and protective devices: 1) The needle valve or globe valve at the front end of the pressure gauge bend should be in an fully open position. The pressure gauge meets the requirements in terms of accuracy, range, and dial diameter; the pointer returns to zero when there is no pressure. 2) The valve at the drain pipe of the level gauge is closed, and the drain pipe is properly connected to the storage tank. 3) The thermometers and automatic recording instruments have been calibrated and found to be in good condition ； Over-temperature and over-pressure alarms, as well as automatic interlock protection devices, are in operation; there are no abnormalities at any of the electrical control contacts. 4) Inspection of combustion ventilation equipment: no abnormalities found. 2. Medium testing and cold-cycle operation: The quality of the heat transfer fluid used in organic heat carrier boilers is of great importance for the safe operation of these boilers. Therefore, it is necessary to take samples of the heat transfer fluid in use for testing, or to obtain relevant quality certificates from the supplier. It is essential to confirm whether: 1) the maximum operating temperature of the heat transfer fluid is compatible with the heating conditions of the organic heat carrier boiler. The outlet temperature of the furnace should be at least 30–40°C lower than the maximum operating temperature allowed for the heat transfer fluid; otherwise, the heat transfer fluid will decompose and deteriorate rapidly during use, leading to premature failure. 2) Sampling and testing are carried out to determine the visual quality, flash point, viscosity, acid value, residue carbon, and moisture content of the heat transfer fluid, to check whether they match the quality certificate provided by the manufacturer of the heat transfer fluid, and also to provide a basis for monitoring any changes in the quality of the medium during future operation. Filling with fluid: The heat transfer fluid that has passed the quality tests is injected into the furnace and the expander using a filling pump. When the fuel pump injects the heat transfer fluid into the system, it is necessary to check once again whether the drain valves and oil release valves of the furnace body, heat-using equipment, and piping systems are properly closed, in order to prevent loss of the heat transfer fluid. At the same time, open the steam release valves on the pipes and furnace one by one to remove air, and close them once oil begins to flow out. Stop feeding the heat transfer fluid when oil level appears on the expander level gauge, then start the circulation pump to initiate a cold-state circulation. Cold cycle: The purpose of the cold cycle is to test whether there are any obstructions in the entire heating system, to check for leaks in equipment, pipes, valves, etc., and to determine whether the flow rate and head capacity of the circulation pump meet the requirements of operation. Due to the high viscosity of cold oil, the pressure difference between the inlet and outlet of the heat carrier furnace is relatively large, and the flow resistance in the piping system is also high. Each circulation pump should be started and tested in turn, allowing the cold oil to circulate within the system for 6 to 8 hours. During the cold-state cycle, it is also necessary to frequently open the vent valve to release any residual air. Monitor and record the readings from pressure gauges, thermometers, ammeters, etc. at various points. Pay attention to recording data such as the current of the circulation pump, the pressure difference between the inlet and outlet, the outlet pressure of the circulation pump, and the pressure difference between the inlet and outlet of the organic heat carrier furnace. Additionally, check whether the oil pump is operating smoothly and whether the bearing seals are in good condition. Remove and clean the filter: During the cold-cycle operation, various impurities in the system as well as residues in the heat transfer fluid are filtered out by the filter located before the oil pump, as the cold oil circulates. Once the cycle is complete, the filter should be removed to eliminate all dirt from inside it and on its filter elements. 4. Ignition and heating steps: The ignition procedures vary depending on the type of combustion device. The most common types of combustion devices are manual-fired grates, chain grates, and briquette grates. Operation procedures for manual-fired grates: 1) Ignition steps: a) Fully open the flue dampers and ash doors, and allow natural ventilation for 10 minutes. If there is an exhaust fan, run it for 5 minutes. Then close the gray door, lay wood and kindling on the grate, sprinkle a thin layer of coal on top, and place more wood on that layer of coal. b) Light the wood on top of the coal. It can be ignited using cotton yarn dipped in machine oil; the use of highly volatile oils for ignition is strictly prohibited. The furnace door can be opened halfway. c) Once the fire has ignited the coal, add a small amount more coal to keep the combustion going. 2) Normal combustion: For a manual furnace to burn properly, it is essential to follow the principles of \"less, frequent, and quick\" – that is, coal should be added frequently, and new coal should be introduced as soon as the coal layer in the furnace reaches a state of white-hot burning ； The coal feeding action must be quick; the coal should be spread in small amounts but evenly, to maintain a coal layer thickness of 100–150 millimeters and ensure uniform ventilation. At the same time, an appropriate amount of water is added to the coal to improve combustion efficiency. The stoker should carefully observe the color of the fire, and adjust its combustion by pulling back the flames or poking at them. When the flame turns white, it indicates an excess amount of air, and coal should be added promptly. When the flame is orange-red, it indicates insufficient air supply; in such cases, it is necessary to \"stir the fire\" by pushing the ash and debris beneath the coal layer downward, thereby loosening the coal layer and improving ventilation. When a crater appears locally and the flame turns white, it is necessary to \"adjust the fire\" by using a fire hook to level out the coal layer. “When \"stirring the fire\" or \"fanning the fire,\" the movements must be quick to prevent the furnace door from staying open for too long, which would allow too much cold air to enter the furnace and lower its temperature ； It is also necessary to prevent furnace ash from being stirred up into the combustion layer; any lumps that form should be removed using the door hook, rather than being crushed by force. Operation of chain grate stoves 1) Ignition procedure a) Raise the coal gate to its highest position, spread a layer of coal 20–30 millimeters thick in front of the grate; place kindling materials such as wood or old cotton yarn on top of the coal. Spread a thinner layer of slag in the middle and rear part of the grate to prevent large amounts of cold air from entering. b) Light the kindling, slowly rotate the grate to bring the fire to a distance of 1~1.5 meters from the coal gate, then stop rotating the grate. c) When the temperature of the current arch rises to a level sufficient to ignite the new coal, adjust the coal layer shutter to maintain a coal layer thickness of 70–100 millimeters. Slowly rotate the grate and adjust the induced draft fan so that the negative pressure in the furnace chamber is close to zero, thereby accelerating combustion. d) As the burning coal moves with the grate to the second, third, and fourth air dampers, open those dampers appropriately to allow the combustion to continue. e) Once the kindling covers the grate, thicken the coal layer appropriately and increase the air flow accordingly to maintain a negative pressure in the furnace of 2~3 millimeters of water column. 2) Combustion adjustment: The combustion adjustment for chain grate furnaces mainly involves adjusting the coal layer thickness, grate speed, as well as the blowers and exhaust fans. a) Coal seam thickness: When the coal seam is of appropriate thickness, ignition begins 200 millimeters in front of the coal gate, and combustion is complete 400 millimeters in front of the slag retaining iron (eagle iron). For bituminous coals with high cohesion, the thickness should be slightly reduced, while for those with low cohesion, it should be slightly increased. b) Grate speed: The normal grate speed should ensure that 2/3 of the entire grate surface is covered by the fire bed, with no red flames remaining near the slag retaining iron. When the heat supply increases, appropriately increasing the grate speed can extend the fire bed ； When the heat supply decreases, the grate speed is appropriately reduced to shorten the fire bed. c) Air volume: During normal operation, the opening degree of each air chamber beneath the grate should be adjusted promptly according to the burning conditions; when burning coal with high volatile content, the blast volume should be concentrated in the middle to front portion. When burning coal with low volatile matter, the air volume should be increased gradually from front to back. To reduce combustion, the damper at the outlet of the blower can be closed ； To enhance combustion, it is necessary to increase the air supply volume. The air supply volumes of the drum and the induced draft fan should be matched to maintain a negative pressure of 2~3 millimeters of water column in the front part of the furnace. The adjustment of coal seam thickness, grate speed, and air supply are interrelated; close coordination among them is necessary to maintain normal combustion. Operation of the briquette furnace grate 1) Ignition procedure: a) Fully open the chimney damper and allow natural ventilation for 10 minutes. Then, place wood and kindling inside the furnace chamber, and push in 4–6 carts filled with briquettes before closing the furnace door. b) Start the circulation pump; after confirming normal operation, ignite it through the ignition hole. c) After the organic heat carrier furnace has been operating for 12 hours (depending on the quality of the briquettes), coal equivalent to the amount of coal that has burned off is added. 2) The amount of briquettes required for an organic heat carrier furnace during normal operation can be adjusted according to the heat demand of the equipment. 3) In the event of a power outage or a failure of the circulation pump, to maintain normal and safe production, the inlet and outlet valves of the circulation pump can be quickly closed, and the diesel engine-driven circulation pump can be started. 4) The requirements for guitar operation can be referred to in the relevant sections of these procedures. Heating up and heating curve: The ignition and heating process of organic heat carrier furnaces is a relatively dangerous stage during operation, requiring particular caution; the heating process should follow the principle of \"slow first, then stop.\" ； First, the heating rate must be slow; second, heating must be stopped at two temperature ranges: 95°–110°C and 210°–230°C, and this temperature level must be maintained for a period of time. 1) Heating curve: After the heat carrier furnace is ignited, the heating process and rate are carried out in accordance with the provisions of the heating curve. The typical temperature rise curve of the heat carrier is shown in Figure a) below: after the cold furnace is ignited, the temperature rise rate is controlled at 10°C per hour, until it reaches 90–95°C. Because the viscosity of the oil is high when the furnace is cold, the flow velocity inside the heat-exchanging tubes is low, the oil film on the tube walls is thick, and the heat transfer conditions are poor; if the heating rate is too fast, it can easily cause the temperature of the local oil film to become too high. b) The range of 95~110℃ is the stage for driving out the residual moisture in the system and the trace amount of moisture contained in the heat transfer fluid. The heating rate should be controlled within the range of 0–5°C per hour, depending on the dehydration progress. When the steam discharge volume at the expander’s vent pipe is high, there is a water hammer sound at the bottom, pipeline vibration increases, and the pointers of the pressure gauges fluctuate significantly, it is necessary to stop raising the temperature and maintain a constant temperature; if needed, the furnace door can be opened to reduce combustion. The duration of this stage varies depending on the amount of residual water in the system and the quality of the heat transfer fluid; it can be as short as a few dozen hours or as long as several days. It takes several cycles at temperatures between 95~110°C to remove all the water completely. It is not possible to blindly accelerate the heating and dehydration process, as once the water in the system evaporates rapidly, its volume will expand sharply. This can not only lead to \"boiling over\", causing the oil level to rise abruptly and result in large amounts of oil being ejected, but it may also cause the pressure throughout the system to increase drastically, leading to the rupture of pressure-bearing components and serious accidents. c) When the noises inside the furnace and in the pipes decrease, and the circulating oil pump no longer experiences vacuum conditions (the pressure at the pump outlet drops below 0.1 MPa, with a heavy hissing sound), the temperature should be increased at a rate of 5°C per hour, but not above 120°C, until no gas is more emitted from the vent pipe. At this point, when the pressure gauge pointer stops fluctuating, it indicates that the dehydration is successful. d) After the dehydration process is complete, continue to raise the temperature at a rate of 30°C per hour; however, be aware that residual water may still evaporate, so stop raising the temperature at any time. The process must be stopped when the temperature reaches 210–230°C, as this is primarily the time for the hydrocarbon components to be removed from the heat transfer fluid. The presence of hydrocarbon components in the heat transfer fluid lowers its flash point, increasing the likelihood of deflagration in the event of a leak. In a heat carrier furnace fed with a liquid phase, the hydrocarbon components exist in the gas phase, which can cause a \"gas blockage\" and result in unstable pressure in the circulation pump, as well as a decrease or even interruption in flow rate. The analysis process for the light-end removal group varies depending on the different grades and qualities of the heat transfer fluid; when no gas is discharged from the vent pipe and the pressure of the circulation pump remains stable, it is possible to continue raising the temperature at a rate of 0–10°C per hour. e) From 210°C up to the operating temperature of the heat transfer fluid, after the light removal process is completed, the temperature should be increased at a rate of 40°C per hour. At this time, it is necessary to thoroughly check the readings of all the monitoring and control instruments to ensure that they function properly and accurately. Check whether all auxiliary machines and supporting equipment are operating properly, and conduct a thorough inspection of the boiler and heating system to ensure they are functioning correctly and can meet the production requirements. If the heat supply does not meet the design requirements, heating should be paused to identify the cause; heating can resume only after the issue is resolved. 2) Precautions during ignition and heating up: a) During the ignition and heating up process, it is necessary to follow the heating curve specified in the \"heating curve diagram\" strictly. b) When the temperature of the heat transfer fluid rises above 200°C, a thorough inspection of the equipment and the entire system should be carried out, and all bolted connections should be tightened to eliminate leaks caused by uneven thermal expansion. c) Pay attention to the expansion amount of the heat transfer fluid. If the liquid level in the expander is too high, the drain pipe should be opened to pour the heat transfer fluid into the oil storage tank, thereby preventing excessive leakage of the heat transfer fluid from the expander and avoiding accidents. d) When lighting the cold furnace, the circulation pump must be turned on first before ignition. In cold regions, the heat transfer fluid should be heated to around 30°C using steam before ignition, and only then can the circulation pump be started. e) During the ignition and heating process of the liquid-phase furnace, the water removed is carried in the form of water vapor through the expansion tube to the expander; part of this water vapor is discharged as gas through the vent pipe, while the other part condenses into water and settles at the bottom of the expander. To prevent this water from re-entering the circulation system, it is necessary to regularly open the drain pipe at the bottom of the expander during the heating process in order to release the condensed water.