At 21:00 on March 13th, 2009, during the normal production process, the on-site personnel found that the oil pressure of the 2# air compressor slowly decreased from 0.269MPa to 0.238MPa, and the oil filter pressure difference increased from 0.08MPa to 0.12MPa. However, the alarm value (0.2MPa) is not reached. After switching the standby oil pump, the oil pressure is stable at 0.24MPa, but the pressure difference of the oil filter rises slightly to 0.13MPa. At the site of the fuel supply system, the oil supply pipeline and the air supply After the press site did not leak oil, contact the inspector. The inspector requested to adjust the oil pressure of the oil pump, but the oil pressure did not change. When the inspector arrived at the scene on the 14th, the oil level of the fuel tank was very low, and the oil level was only higher than the oil pump. The pumping mouth is a few centimeters high. After confirming that the water sample in the drain port of the air-cooling tower drain side contains oil, it is judged that the lubricating oil has leaked a large amount into the circulating water. Because there are no signs of oil leakage around all pipelines and equipment on the site of the fuel supply system, it is preliminarily judged that the possibility of leakage in the oil cooler is the greatest. The air separation system requires absolute oil ban, and the oil entering the air separation system is prone to explosion when it is in contact with liquid oxygen or high concentration oxygen. In order to prevent the lubricating oil from entering the air separation system through the air cooling tower (water and raw air are directly in the air cooling tower) Contact with heat exchange) caused a serious safety accident, the workshop requires immediate stop 2 # oxygen generator, taking into account the 2 # oxygen machine circulating water system and 1 #,3 #,4 # oxygen generator sharing, to prevent accidents Expanded, and then stopped 1 #, 4 # and 3 # oxygen generators, stop circulating water pumps. Drain, clean and degrease the circulating pool. Then the workshop immediately formulated a repair plan: (1) Drain the circulating pool and clean it, then refill the pool, add degreaser, start the pump to degrease and drain the water in all circulating water systems. (2) Remove the oil cooler end cover, pressurize the oil cooler, find the oil leaking tube bundle and plug it with a plug. (3) The lubricating oil discharged from the oil drain port of the fuel tank is already a mixture of oil and water. It is necessary to check whether the bearing of the air compressor is damaged due to poor lubrication. In the process of repairing, the workshop is also carefully analyzing and judging the possible impact of the accident. How to ensure the long-term safe operation of the air conditioners of the three oxygen generators is the key to the successful completion of the repair work. Whether to thoroughly clean the packing of the air cooling system. Based on the analysis of the on-site situation, the workshop believes that if all the cooling water contact parts are cleaned, it takes 1~2 weeks or even longer, which will have a great impact on the whole plant production; because the air passes through the air cooling tower, it will enter the molecular sieve purification. The system adsorbs water and CO2 and some hydrocarbons. After oil leakage, the airborne detection of molecular sieves does not find that the CO2 content exceeds the standard. It can be judged that the molecular sieve works normally. The air cooling tower does not carry water through the molecular sieve, so it can be judged: oil leakage for a long time. It does not enter the air separation unit (at least not through the molecular sieve, it is adsorbed in the adsorption stage of the molecular sieve). Through the above analysis, the workshop judged that a large amount of oil leakage did not enter the air separation unit. After draining the oil circulating water, the newly added water will make the oil content in the water slightly smaller than the previous stage. The on-site water treatment experts believe that it is used at the same time. The degreaser will remove most of the residual grease. Therefore, a very small amount of grease cannot be concentrated into the air separation unit, and will not affect the normal production of the air separation system. The chemical analysis can be strengthened in the production process, and the main cold liquid is discharged in an abnormal manner. Through careful and careful analysis, it was decided to implement the original repair plan. After inspection, the air compressors have good bearing status at all levels, no obvious signs of wear, but there is water ingress on the bearing surface; 2#The internal tube bundle of the air compressor oil cooler has a break, which is the main cause of a large amount of lubricating oil leakage. 2 reasons analysis (1) 2 #Air compressor oil cooler tube bundle is broken due to long service time (12 years). One of the cooling water pipe bundles breaks, which is the direct cause of a large amount of lubricating oil leaking into the circulating water. (2) The on-site operator did not conduct on-site inspection according to the standard operation requirements, and did not find the fuel tank oil level drop in time. (3) The inspector did not realize that the seriousness of the problem did not go to the scene to deal with the problem in time, but only the operator's oral command to adjust the oil pressure. (4) In the previous year's annual repair, the oil cooler was not subjected to pressure test leaks, and the opportunity to leak the oil cooler tube bundle was missed. (5) There is a certain quality problem in the oil cooler. In the second year of the initial use of the equipment, it was found that there was a tube bundle leakage phenomenon. 3 Conclusion This equipment accident has greatly affected the production of the factory. The downtime is as long as 22 hours. If the problem can be found in advance, the time and method of dealing with the fault will remain basically the same, but the risk of accidents will increase. After careful analysis and summary of the accident, the workshop recognized the loopholes in management and adopted a series of targeted rectification measures to provide management and institutional support for timely detection and handling of problems in the production process. Guarantee.
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1 The occurrence process and judgment processing of the accident