Induced draft fan o-rings aging oil, boiler MFT

Induced draft fan o-rings aging oil, boiler MFT - 2020 04 - 21 prior condition ( On June 8, 2019) 178 mw unit load, 1 a, 1 d, 1 e pulverizing system running, the total coal 81 t/h, total air volume of 692 t/h, hearth negative pressure - 92 pa, unit coordinated way. Induced draft fan current 266 a, 29. 0 8%, oil pressure. 37 mpa, control oil pressure 3. 89 mpa, A lubricating oil pump operation, B lubricating oil pump. Set aside. The incident now, run the attendant supervisor plate found that the oil pressure control device of induced draft fan fell to zero. Lian kai 03 mpa, standby pump. Attendant immediately for checking on-site inspection, the dedicated contact maintenance equipment, reply: induced draft fan control oil pipe and oil hose connection joint, to report the long-term value. Notify the maintenance processing funnelled as soon as possible, and prepared to go. Land, the maintenance personnel arrived at the scene, the oil spill area after tight, and arrange personnel to fill the oil to fuel tank oil, after double tight, oil leakage was not significantly reduced, failed to achieve. Tank, to the number of induced draft fan 'low oil level alarm, induced draft fan control hydraulic oscillation and gradually decline, for checking on-site inspection induced draft fan of the opening of the moving blade, and the induced draft fan rotor power outages. Figure 1 induced draft fan control oil pressure and the induced draft fan of the opening of the moving blade curve of lift crew coordination, induced draft fan current continue to fall by 265 a, hearth negative pressure increasing, the biggest increase to 2263 pa. Rapidly reduces the load and into A layer D oil gun, pass small air supply motor, oil pump shut down, and the filling oil. Inform maintenance tubing funnelled. 15:03 on June 8, load 45 mw, hearth negative pressure 1560 pa, first out 'lose all fire alarm of the boiler, the boiler MFT, machine, furnace, electric interlock protection movement is normal, the unit stops. Figure 2 furnace pressure history curves before and after the three main steam pressure, the main steam temperature curve history 'on June 8, start the electric feed water pump, open, high steam for shaft seal. And on June 8, no. 1 induced draft fan shutdown, station suspended, disassemble control the import of oil pipe joint found internal o-rings aging rupture, seal failure. Figure 4 damage for type O sealing ring on June 8, destroying the vacuum, withdrew from the shaft seal, close all hydrophobic watergate. So when on June 8, maintenance personnel will be induced draft fan tubing funnelled to replace o-rings and fill oil and normal oil level. Start the gas station, to check the oil pressure, control oil pressure is normal, no permeability, oil spill; Complete tank of gas, control oil pressure gradually returned to normal. Immediately adjust the induced draft fan rotor, actuator movement is normal, but the actual instructions action is smaller. Figure 5 1 induced draft fan control oil pressure, current, rotor curve into the induced draft fan internal inspection, found that leaves actuator deformation of connecting rod, need to replace the connecting rod, 17:34, connecting rod to replace. Debugging moving blade switch to normal. 23:57 on June 8, startup boiler no. 1 specific system. On June 9, 00:34, ignition unit. This unit belongs to the extremely hot start-up, the full stop and start the boiler unit in the plant parameters can not meet the requirement of the steam turbine shaft seal steam parameters, can only be fully shaft seal steam from the boiler produced steam, in order to meet the requirements of turbine shaft seal steam parameters, the boiler from ignition to the shaft seal steam supply takes longer. On June 9, 05:35, steam turbine, affected by the unit after tripping no spare auxiliary steam, the steam turbine shaft seal steam completely on the boiler pressure steam supply, with the loss of the boiler pressure, the front axle seal steam supply parameters appear high pressure cylinder and the cylinder temperature mismatch problem, resulting in the rotor due to bending, steam turbine at turn of up to 1500 RPM, # 3 shaft vibration is big, slow down to 500 RPM, the DEH fault tripping speed; 06:17 to hang a brake to rush to 1100 RPM, # 3 shaft vibration biggest 200 um, a brake; 06:53 turbine speed to zero and turning. On June 9, 10:03 turbine blunt, blunt turn vibration in the process of maximum bearing vibration # 2: X to 162 um, Y to 99 um. In the constant speed of 3000 RPM. On June 9, 13:02 grid. Cause analysis, induced draft fan control the import of oil pipe joint internal o-rings, aging and erosion caused by high temperature and high pressure for a long time damage fracture, seal failure, resulting in oil pipeline leakage, fuel tank oil level rapidly drops, oil pump can't normal suction, control oil pressure falling fast, induced draft fan rotor down quickly, furnace at positive pressure is too large, the boiler combustion deterioration, lose all fire protection, boiler MFT. Question 1. Induced draft fan station two pump Shared a line, when the tubing failure cannot be removed. 2. Maintenance entries are not complete, failed to control the tubing connector type 'O' ring to examine what is included in the preventive maintenance. 3. Maintenance of equipment maintenance management does not reach the designated position, for equipment maintenance is not careful, failed to find abnormal equipment. 4. Staff insufficient recognition of importance of single series of auxiliary equipment, equipment daily check is lax. 5. Operation department of main auxiliary equipment fault accident forecast is not sufficient. 1. According to four years, have been put into operation in unit of the equipment maintenance department with aprons census, partial replacement. 2. In order to strengthen the management of equipment maintenance plan, maintenance of important equipment project planning audit checks. 3. Three big fan station for technical renovation of oil pump valve, cut-off valve, tubing of oil spill increase dual channel, improve equipment reliability. 4. In order to strengthen the management of overhaul quality acceptance, further standardize and optimize the quality of maintenance, and in strict accordance with the technical requirements for maintenance, found maintenance quality hidden trouble in time to eliminate. 5. In order to strengthen the management of daily equipment inspection, especially in high temperature, high pressure and large regions of the vibration equipment inspection, ensure timely find hidden danger and processing. 6. Strengthening operation personnel skills training, completes the main auxiliary equipment accident forecast, improve the ability of the accident. （ Electricity delivery - know)