Judgment and Treatment of Leakage of Cooling Machine Cooler Zhang Baofeng, Ma Jianjie, Gu Shouquan, Liu Yongdongshan Tanggang Gas Co., Ltd., Tangshan 063016, Hebei, China) Stable operation, timely analysis and judgment of handling faults is very important. The technical parameters of the air compressor during the operation are introduced. The causes of the shaft vibration fluctuation during the operation are analyzed. The fault repair and repair process is expounded.
1Overview of the 25000/25000-900 air separation unit, 1* air separation is manufactured by Sichuan Air Separation Equipment Manufacturing Plant, and the supporting air compressor is Cameron (Kamai ring centrifugal air compressor, air compressor rated air volume is 128000m3/h The exhaust pressure is 0.49 MPa (A). The air compressor was put into operation in 2008. Through 4 years of operation observation, the equipment runs smoothly.
Since the equipment is put into operation, all the parameters are within the control range and the operation is stable. The air compressor compression unit air energy consumption is basically the same as the working condition.
2 Failure phenomenon 1 The air compressor has abnormal operation since February 13, 2012. Recent analysis and summary of operating parameter change data as shown in Table 1. Table 1 Abnormal data and historical data comparison table Time exhaust pressure Secondary inlet Three-stage inlet current - Level inlet Secondary inlet Three-stage inlet Primary shaft vibration Secondary shaft vibration Three-stage Axis vibration flow pressure APa temperature / * C trend flat increase slightly decrease increase slightly increase flattening trend flat increase slightly increase flat increase increase flat according to the same period of the same gas volume in the same period of the data comparison, and (D two, three The increase in inlet pressure indicates that the primary pressure ratio increases and the tertiary pressure ratio decreases; the compressor performance curve has deviated from the original value.
0 current increases, indicating that the air compressor consumption increases; (3 third-order shaft vibration has increased from the end of August 2011; to the present increase of 11ixm. large; to now increase 12. * three-level inlet temperature from 2011 It began to rise in September, indicating a drop in efficiency of the secondary cooler.
3 Reason analysis The operation personnel also found that there was no condensed water in the first-class cooler before February 13th, but there was water after February 13th. After testing, the water quality was circulating water. According to the data changes and the condensed water situation, it is preliminarily believed that the segment cooler has a leak, causing fouling of the secondary cooler and reducing the efficiency. Therefore, we further tested the resistance of the primary and secondary coolers and found that there is no resistance in the stage cooler, and the secondary cooler resistance is about 10 kPa.
Analysis reason 1 The current operating state of the air compressor is increased due to the micro-leakage of the first-stage cooler, the fouling of the second-stage impeller and the increase of the vibration; the cooling effect of the second-stage cooler is reduced.
4 Treatment measures In order to ensure the normal operation of the air separation, in the face of rising temperature, through the multi-party communication with the user, decisively take the parking maintenance program, the parking maintenance opportunity is difficult to arrange the repair time to 1 air compressor 2 coolers Perform disassembly checks, repair coolers and increase cooling efficiency. Check the fouling of the impellers at all levels and clean them.
Arranged for maintenance in April, the air compressor cooler was opened on the day of maintenance, and a large amount of fouling was found on the connected pipeline deflectors at all levels. The fouling of the air compressor impeller was also serious. The fouling in the air compressor cooler and the partial blockage of the heat exchanger not only affect the heat exchange efficiency but also cause the gas drift phenomenon.
In order to effectively remove the fouling of the air compressor cooler and the impeller, the weakly acidic chemical is first configured to spray the deflector, and then the impeller deflector is similarly treated, and finally the cooler is heated on the gas side ( Adding a weak acidifying agent) soaking for 8 hours while using steam heating is desirable to remove the cooler fouling impurities.
After several repeated cleanings, enter the cooler to check the descaling effect (continued from page 27). 5 Problems and suggestions Some problems found in the equipment during commissioning: (1) During the commissioning, the nitrogen compressor was found to stop. The gas path of the three-stage cooler can discharge water, indicating that there is leakage in the intercooler; oil leakage of the air compressor and the like. It is recommended that equipment manufacturers strengthen quality management in equipment manufacturing to ensure long-term safe and stable operation of equipment.
0 oxygen permeability imported filter internal parts are not in accordance with the "deep freezing method for the production of oxygen and related gas safety technical regulations" GB16912-2008 using copper and copper alloy, which does not meet the national standards, there are security risks, we have provided the problem equipment Manufacturer.
(3) Due to the low design height of the venting port of the oxygen turbine compressor during commissioning, the distance from the air compressor is relatively close. When the oxygen is vented, the suction pressure of the air compressor is affected, causing process fluctuations. After we have rectified the situation, the situation has been Great improvement.
The result is good. At the same time, it is found that the scouring of the long-term airflow has caused the deformation of the gas-side fins of some of the coolers, and the air-side cooler fins are also corrected.
Three leaking pipes were found when the cooler side was pressed, and the three channels were blocked.
5 After the inspection and maintenance analysis, the air compressor was started according to the plan. After the air compressor was started, the operation data showed that the air compressor was running smoothly after the maintenance. From the analysis of the operation in recent days, the air compressor saved 25,200 kW per day. The air compressor operating efficiency increased by 8.5%, the secondary cooler outlet temperature decreased by 810. The shaft vibration did not change, the secondary and tertiary shaft vibrations decreased by 8|xm, the secondary inlet pressure dropped from 125kPa to 79kPa, and the tertiary inlet pressure was reduced. The 246 kPa dropped to 201 kPa, and the operating current dropped from 750 A to 678 A, achieving the expected maintenance target.
The secondary and tertiary pressure ratios increase, and the stage pressure ratio decreases; the compressor performance curve has returned to the original value. The current is reduced, indicating that the air-voltage consumption of the air compressor is reduced; the power consumption is 25200 kW per day, and the efficiency is increased by 8.5%. The vibration of the shaft is stable. The vibration of the secondary and tertiary shafts drops by 8|xm. The temperature of the third-stage inlet drops from 810 *C, indicating that the efficiency of the secondary cooler is improved. Disposal of the stage cooler after maintenance.
6Experience and experience Through the above-mentioned air compressor cooler repair and repair, after practice comparison, the vibration of the secondary and tertiary shaft of the air compressor is reduced. The efficiency of the cooler is improved, and the overall efficiency of the air compressor is increased by 8.5%. The purpose of energy saving and maintenance is achieved, and the experience and method of repairing such problems are summarized in actual operation. Pay attention to the operation of the air compressor and the analysis of the efficiency change. It is directly affected the continuous operation capability of the equipment.
Li engineering major, bachelor degree, assistant engineer, is now engaged in process technology management.
During the operation of the air compressor, the shaft vibration gradually increased, and there was a hidden danger in operation. After two treatments by the equipment manufacturer, the problem was solved.
The delivery flow rate of another air compressor has not reached the design value, and the manufacturer has been required to cooperate.
Many similar problems were found and solved in the debugging, including the problems of the automation program, we have all rectified.
6 Conclusion Two sets of 20000m3/h external compression oxygen generators are advanced in design, reasonable in configuration, compact in installation, easy to operate since operation, stable in operation, and meet production requirements, especially the nitrogen output of air separation equipment is 20,000 compared with the equipment order contract. Production increased to 40,000 production, and a backup guarantee was provided in the case of increasing nitrogen use by steel companies.
Technical University), senior engineer, has long been engaged in oxygen technology professional process technology management.
Metallurgical power
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