Yanyan Datang Inner Mongolia Duolun Coal Chemical Co., Ltd. (hereinafter referred to as: Datang Duolun) Coal Chemical Project Three sets of 58000m3/h air separation equipment supporting air compressor units adopt imported products, steam turbine 0.479MPa; air boost The machine is RG56-5 centrifugal compressor, the five-stage outlet flow is 87000m3/h, and the exhaust pressure is 6. The air compressor unit is the first set of RIKT140 and RG56 centrifugal compressor combined units in China.
In the actual operation process, the air compressor outlet anti-surge venting valve has poor positioning effect and the venting pipeline has large vibration. After two transformations, the valve positioning and pipeline vibration condition can be effectively improved. At present, the technical problems of the technical department of the General Coal Chemical Co., Ltd. are engaged in the technical management of the problems encountered during the operation of the air compressor and the corresponding improvement measures.
Knot, for peers.
1 The air compressor anti-surge venting valve is slow to respond to the start of debugging. During the operation of the later operation, it was found that the anti-surge venting valve of the air compressor was slow to respond. After the output signal of the ITCC system, the valve position feedback was generally about 5 minutes to keep up; in addition, the valve position feedback amount was different from the input value, and even This causes the air compressor unit to be unloaded (the unit is unloaded when the valve position feedback value differs from the input value by more than 20%). This phenomenon is particularly noticeable in winter.
Before each driving, the instrument control personnel will debug all the valves. When the unit is out of service and the pipeline has no medium, the valve switch debugging is normal.
When the air separation equipment is fluctuating, the anti-surge venting valve of the air compressor can not be adjusted in time. The emergency shutdown of the air separation equipment after the unit is unloaded will seriously affect the air supply of the downstream equipment and even cause heavy losses.
2 Reason analysis and solution 2.1 The first modification analysis After analysis, it is believed that the reason for the slow response of the air compressor anti-surge vent valve is: (1) The number of right-angle elbows of the pipeline before the anti-surge vent valve of the air compressor exit is large (5) ()), when the gas flows through the right angle bend, it will generate large noise and the wall vibration is large; (2) the straight pipe section is short before the valve, and the airflow impacts the valve flap to cause damage; (3) the air compressor outlet anti-surge vent valve The installation position is outdoors, and the outdoor temperature in winter is as low as -38*C. The valve positioner has poor low temperature resistance, slow tracking and difficult positioning.
According to the above analysis, the opportunity of parking overhaul at the beginning of the year is used to first move the anti-surge vent valve of the air compressor of the air compressor of 158000m3/h from the outside position of the plant (1) to the horizontal pipe section (2) in the plant (as shown ), in order to increase the length of the straight pipe section before the valve, reduce the impact of the gas on the valve flap, and at the same time make anti-freezing insulation measures for the anti-surge vent valve progress, cancel the valve position feedback value and the ITCC system output value difference of more than 20% Unlock the interlock. Add a tube holder J10 (type I) to the steel platform beam of EL12.500 before and after the valve. The anti-surge venting lines of the other two air separation units air compressors were also modified in accordance with this plan.
During the operation of the air separation plant in the future, there was no longer a problem of slow reaction of the air compressor anti-surge vent valve.
2.2 The second transformation analysis During the operation of the air compressor, the anti-surge vent valve always has an opening degree because the working condition does not reach full load. After the displacement of the anti-surge vent valve, a new problem arises, that is, the vibration of the pipeline after the anti-surge vent valve of the air compressor unit of the air separation unit increases, and multiple cracking and damage occur successively. The damaged part of the venting pipe is mainly in the form of branches and blocks. After the repair and repair of the damaged part of the pipe, the rear pipe section of the valve and the position of the original valve are still damaged near the elbow.
In view of the safe operation of the equipment, the pipe arrangement before and after the displacement of the anti-surge valve is discussed and discussed several times. The reasons for the analysis are as follows: (1) The cracked and cracked parts of the pipeline are in the vicinity of the original installation position of the anti-surge vent valve, and are concentrated in the original valve. The front elbow is on the pipe before and after. According to the analysis of pipeline cracking and damage, it should be caused by pipeline stress.
(2) The original anti-surge vent valve is in the outdoor U-bend, and the pipe is expanded from DN700mm to DN1600mm, and the bag-type pipe damper is installed to reduce noise. Since the valve displacement is simply moved from the outside to the inside of the room, the position of the pipe damper does not change and the pipe diameter does not change, and the stress problem of the pipe after the valve is displaced is not carefully considered. In addition, 1 air separation unit air compressor anti-surge vent valve front vertical pipe section bracket is a fixed bracket, which limits the free expansion and contraction of the pipeline. The 3 air separation equipment air compressor anti-surge venting valve front vertical pipe section bracket is a sliding bracket, the pipeline still appears cracking and damage. Therefore, the main reason for the cracking of the venting pipe is that the distance between the anti-surge vent valve and the damper member is elongated. After the gas is vented through the anti-surge vent valve, the DN700mm pipe with a length of about 8m is passed to the damper member of the original valve, resulting in the pipe stress. Move forward to the weak position of the front elbow support pipe of the original valve, and the high frequency vibration of the pipe wall will cause the pipe wall to crack and break.
Using the parking opportunities in August 2011, the air compressor venting pipelines of the three air separation units were re-engineered. After the venting valve, the pipe diameter was thickened and the pipe wall was thickened. The damper was directly moved forward to the valve expansion. And cancel the original venting pipe down the plant wall and then bend up to the U-shaped pipe of the muffler, after the transformation into the factory, the straight pipe section is bent down until the muffler is emptied, the pipe vibration is obviously reduced and no pipe damage occurs. The modified venting pipe is as shown.
3 Conclusion The air compressor venting pipeline has two good effects, and the air separation equipment has been running stably. It has laid a solid foundation for the company's follow-up equipment to open the process and produce qualified products, and realized the analysis of the air separation equipment sub-equipment technicians. The idea has been expanded, accumulated experience in engineering design and installation, and provided valuable experience for the operation of the same type of air separation equipment. It also cultivated the meticulous, responsible and responsible working attitude of the engineering and operation personnel, and dared to do it. The spirit of innovation.
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