Some thermal power company about 2 b in shandong air preheater of tooth coupling loss of the accident

Some thermal power company about 2 b air preheater in shandong bulletin 2019 - tooth coupling loss of accident 07 - 11 a, accident after December 12, 2018 # 2 unit, 09:51:00 load of 329 mw, 2 a, 2 b, 2 c, 2 e run coal pulverizing system, coal 156 t/h, main steam pressure. 2 mpa, the reheat steam temperature of 561, 561 ℃, 1092 main feed flow. 6 t/h, furnace pressure 25. Pa 6, B side air preheater outlet smoke temperature 133 ℃, secondary air temperature is 317 ℃ heat, hot blast temperature 309 ℃ at a time. 09:57:00 # 2 machine deputy of value a certain inspection found when # 2 b air preheater stalling, main motor running, immediately report the main value of kang a certain and the value of long zhao mou. Ask temperature one, start the auxiliary motor whether can return to normal, told: start is invalid, large shaft coupling collar falls off. Check the DCS air preheater ontology, found 2 b air preheater in 09:51:45 stalling signals. 09:57:46 emergency shutdown 2 e pulverizing system ( After 2 e coal feeder frequently broken coal) Coal, drop to 113 t/h. 09:57:51 RB, plasma ignition since the vote. 09:57:56 removal of RB and reset. 09:58:00 a fan inverter to manually. Contact 10:01:00 blower exports, induced draft fan inlet damper closed, manual stop 2 b induced draft fan, 2 b blower united jumping is normal, import and export couplet GuanZhengChang. Notice of boiler maintenance. 10:02:00 2 b a fan is stopped manually. 10:06:00 start C fuel pump operation. Shut down the 2 b air preheater main motor, main and auxiliary electrical power outage. 10:07:00 load of 145 mw, coal 74 t/h, furnace pressure 105 pa, main steam pressure is 14. 3 mpa, the reheat steam temperature minimum, 530, 494. 8℃。 For 2 a induced draft fan rotor, automatically set pressure 48Pa。 10:00 maintenance personnel arrived at the scene inspection found that 2 b air preheater center cone drum type coupling gland bolts fracture on his coat, reducer coupling and the center tube detaching, coupling gland bolts for a total of 22 (on his coat Specification M10mmX40mm) , confirmed by the check the bolt fracture of article 17, head bolt fracture cross section for the new crop, five central bolt fracture. Boiler overhaul to cruise around 8 PM inspection personnel to check here for 2 b air preheater reducer running normally, coupling with the center tube detaching. Hitches in the repair process measuring drum type coupling concentricity, found that the coupling axial direction 4 mm difference before and after the furnace, furnace left and right are 2 mm, coupling concentricity deviation is serious, after repair 2 b normal operation of air preheater into prominence. Second, the cause analysis, A) Management reason 1, the station air preheater reducer in overhaul repair company in January 2016, replacement, maintenance coupling concentricity is not adjusted, of checking the quality control is lax. 2, down when not included the reducer in check project, running for a long time did not perform missile d etection repair system. 3, daily inspection failed to find the equipment anomalies ( Individual bolt fracture) 。 （ 2) Technical reasons 1, drum type coupling concentricity deviation, uneven of the coat bolts, bolt strength decrease caused by fracture of long period running, is the main cause of the accident. Three, prevention measures and management measures: 1 to do maintenance inspection record, the good maintenance quality. 2, technical measures: strictly implement equipment missile d etection project inspection standards, strengthen the equipment inspection, improve the quality of inspection, using big minor repair time review air preheater coupling concentricity. Four, examine the 2 b air preheater coupling loss caused by the unit load down more than 5% and more than 30 minutes, a equipment of accountability 2 kinds of obstacles. 1, the equipment accidents due to repair quality problems, coupling concentricity is not adjusted, maintenance overhaul company mainly responsible for the mountain. 2, maintenance of the boiler designed worker wang mou a certain, biotech boiler designed work XXL lax management responsibility of checking the quality, the assessment of 200 yuan. （ Source: the electric power production safety)