Steam turbine oil bearing block oil analysis and governance

Steam turbine oil bearing of splashing of oil was blocked 2021 - analysis and management 03 - 02 [ Abstract 】 Steam turbine main tank exhaust fan is mainly to the main tank and various bearing formation micro negative state, oil return for bearing, oil bearing block oil spill. A certain power plant 350 mw unit as the main fuel tank smoke exhaust fan, led to the individual bearing oil to oil leakage. Aiming at the abnormal phenomenon, the platoon lampblack machine for governance, eliminates the bearing oil leak, obvious effects have been achieved. 【 Keywords 】 Steam turbine; Main tank smoke exhaust fan; Oil block; Permeability oil overview of a certain power plant generators are of air cooling generators, steam turbine model for C330 / N350 - 17. 75/0. 981/540/540 subcritical, single axis, double cylinder, double exhaust, adjustable a reheat extraction condensing steam turbine. Each unit the entire shaft bearing on six bearings, four of the steam turbine, generator 2. # 1, # 2 bearings for tilting the support bearing, # 3 and # 4 bearing support elliptical bearing, thrust bearing is located in the high pressure rotor backend, as the rotor and cylinder relative dead center, recently appeared 4 - # 4 machine machine 2, 4 - 6 bearing oil gear oil leakage serious condition, affecting the safe and economic operation of the unit. Therefore, operation management and technical personnel to undertake careful analysis, given the possible reasons, and proceed to rectify for the cause of existence, obvious effects have been achieved. 1, bearing oil, gear oil leakage phenomenon: steam turbine bearing oil, gear oil leakage phenomenon has the following kinds: (1) 4 - 6 bearing outer slightly left oil droplets, causing the bearing and surrounded by dirt, oil spill near the generator excitation system is easy to cause fire. ⑵ 4- 2 bearing oil off the problem of oil leakage remains the same, cause oil pollution around, and 4 - Near the medium-pressure rear axle seal 2 bearing, high temperature and narrow place here, the oil is not easy to clean, easy to fire accident. 2, oil bearing block oil leak reason analysis: the causes of oil gear oil leakage: (1) bearing oil gear clearance adjustment is not appropriate, is beyond the scope manufacturers design, bearing oil gear damage, even cause oil leakage. Fixed bearing oil gear is fixed on the bearing box, and the bearing concentric, can adjust a little. In axis running, its orbit is elliptical shape, direction of the axis of the ellipse must wear oil gear tooth piece, makes the gap bigger, bearing the splashing around in the cabinet of turbine oil along the gap to overflow. Bearing the negative pressure gas from a smaller or positive pressure in the cabinet, lead to oil and gas injection outward, condensate oil drops. After technicians for a long time observation, discover oil file exists outside the minor may not be oil leakage, oil leakage phenomenon but a lampblack condensate oil drops out. Because lampblack is the shaft and bearing friction heating makes lubricating oil, its weight is lighter, natural stay in the upper space of the bearing box, if there is negative pressure bearing, can with the return pipe back to the main fuel tank, but now in the bearing pressure is too small, make the stranded soot density increasing, when the stress reaches a certain value, the inevitable from the break out. More than 3, countermeasures: according to the cause analysis, adopt the following measures. (1) advantage of railway inspection on bearing oil gear, whether there is a gap bigger, readjusted according to the needs of manufacturers in a timely manner. After the work to be immobilized. 2 to screen the main tank smoke exhaust fan system, through the scene view # 4 machine exhaust fan inlet pressure for - 1. 4 kpa, compared to other units on the low side, exhaust fan output, then activate backup is arranged in the January 30, exhaust fan, after start the standby blower, reduce oil bearing block oil leakage phenomenon, this units oil baffle leak is caused by smoke exhaust fan output. Specific data contrast is as follows: further inspection on platoon lampblack machine, found the smoke exhaust fan export balance piping hot, judge may exhaust fan export balance pipeline non-return door installed backwards, which reduces the exhaust fan output, inlet negative pressure smoke exhaust fan, lead to bearing lampblack is not discharged in time, the oil leakage. Our factory # 1 unit is the same problem, need to use service opportunity balance pipe after the collapse of exports to exhaust fan. Now keep two exhaust fan operation bearing oil phenomenon disappeared. 4, summary of unit # 4 individual bearing oil block oil leakage is analyzed, treatment, and found that the bearing oil baffle leak is caused by the exhaust fan inlet negative down, exhaust fan inlet negative is lower due to export balance control non-return plate upside, after being immobilized will non-return board back to solve the bearing oil leak. （ Source: thermoelectric company technology center)