The steam turbine gland ring before loose deformation damage of shallow reason

The steam turbine gland ring before loose deformation damage of shallow reason - 2019 08 - 25 Sun Lihua one, 1 #, 2 # steam turbine downtime reasons and main parameters of operation condition before downtime 17:29 p. m. on June 17, 2014, because of 1 # furnace overhaul, normal shut down 1 # steam turbine generator set. Before 1 # steam turbine downtime data records such as table 1. Table 16 December 22 10:44 points in the morning, because of 2 # boiler economizer leakage, pressure of 2 # furnace fire, normal shut down 2 # steam turbine generator set. Before 2 # steam turbine downtime data records such as table 2. Table 2 2, 1 #, 2 # steam turbine overhaul downtime reasons, and returned to the factory on June 22, 15:30, after processing the defects of 2 # furnace, decided to rev. 2 # furnace, 2 # steam turbine, and points to start turning, after running 2 # steam turbine internal have different sounds, they found these decided to start the 1 # steam turbine, turn 2 # steam turbine overhaul downtime. 0:26 a. m on June 23, 1 # steam turbine at boot. The technology parameters such as table 3. Table 3 after adjusting load vibration still overweight, 1 # steam turbine brake down for maintenance, solve the problem of vibration. Checked in four bearing shell, after the adjustment of the wheel center, to turn, turn on, in the process of the bearing vibration is normal, but hear cylinder with different sound, decided to jie 1 # steam turbine cylinder inspection. On July 12, 1 # steam turbine rotor hanging out, found former gland seal ring damage 3 groups, steam turbine rotor before sealing ring is damaged, July 13, returned to the factory processing. 2 # steam turbine in the repair process, found that the main valve automatically mesh damaged a quarter, steam, steam room, clean the nozzle guide tube and related parts, after July 11, 2 # steam turbine cylinder, the startup disk car found when the rotor is still abnormal sound, jie cylinder to check again. On July 13 in the evening, found 2 # steam turbine rotor of steam seal ring is loose before, on July 14, returned to the factory processing. Three, 1 #, 2 # steam turbine the cause of the accident analysis ( A) Steam turbine inlet temperature and pressure in a short period of time through frequent alternating from June 15 to 18, 1 #, 2 # steam turbine inlet steam temperature, steam pressure, steam flow and the corresponding load curve in operation, 1 #, 2 # steam turbine inlet steam temperature, steam pressure, steam flow and the corresponding load curve short-term volatility is larger, especially on June 15, especially fluctuations, the main steam temperature rose between 101 ℃ in 10 minutes. （ 2) Steam turbine boot time below the factory regulations from 1 #, 2 # steam turbine machine boot book you can see, the 1 # steam turbine from September 13, 2012 to 2013 on May 4, 4 cold boot time see, from main steam automatic door open car to 3000 RPM, a boot time of 51 minutes, longest shortest boot time is 42 minutes at a time, the other two boot time 49 minutes and 45 minutes, respectively; 2 # steam turbine from June 4, 2012-2013 on April 15, 11 cold boot time see, from the main steam door open car to 3000 RPM, the longest a boot time of 64 minutes, the shortest boot time is 41 minutes at a time. And factories require cold boot time is 60 minutes. Steam turbine start-up process, the temperature difference between the various components, the thermal stress and thermal deformation. Turbine most accident occurred at boot time, due to incorrect warming-up conditions, the personnel on duty of wrong operation and equipment itself some structure defects may cause an accident, even if no form directly accident at that time, but the consequences will be in the later production adverse impact. Turbine operation practice shows that the cylinder, valve shell and bending crack of pipe, the steam turbine rotor and cylinder, cylinder flange assembly components combined with the warp, force the change of state of relaxation, metal structure, the increase of bearing wear, and put into operation in the initial stage exposed by other anomalies, are direct consequences start the quality is not high. Steam turbine speed, load and the steam turbine mechanical state of the main changes are: 1, due to the effect of internal pressure, on the tube, cylinder and valve shell stress. 2, in the impeller, round drum, rotor, shaft sleeve, and other moving parts on the centrifugal stress. 3, under the partition indicating, the impeller, the static and dynamic bending stress. 4, due to the transmission torque to the rotor of the generator, turbine shaft tangential stress. 5, due to the vibration of steam turbine rotor. The rotor produces alternating stress and other components. 6, appear on the thrust bearing of the axial thrust. 7, the rise of temperature of the parts caused by thermal expansion, thermal deformation and thermal stress. （ 3) Gland steam temperature on the high side through understanding on the spot, the seal when the phone is switched on for two units of temperature about 330 ℃, both units before steam seal ring material for the 35 # steel, when the temperature exceeds 300 ~ 350 ℃, under the long-term effects of stress are creep phenomenon, and the higher the temperature, the greater the stress, creep speed is faster. （ 4) Steam turbine gland ring before tight force is not enough, improper material selection. By looking for information, domestic small and medium-sized turbine gland body generally loose problems before the interference and to suit the value of small problems, for example, two SongMuPing power plant respectively by Shanghai steam turbine factory and turbine factory manufacturing N25 - wuhan 35 type steam turbine, after put into operation the first overhaul of gland body loose before are found, including 1 # machine gland body suit interference disappeared, about 0. 02 mm clearance; 2 # machine gland body loose is more serious, clearance of 0. 44 ~ 0. 57mm。 Four, the measures 1, standardized operation, reasonable adjustment, put an end to the parameters has appeared frequently the phenomenon of alternating in the start-up, operation, in strict accordance with the rules, downtime, increase or decrease of load and adjusting the operation parameters. 2, adjust the temperature of the steam seal, keep the seal temperature in the range of 200 ~ 250 ℃. 3, improve the existing operating mode, in front of the unit it is forbidden to send shaft seal steam. Source: 'China science and technology expo'