Treatment measures for noise of turbine air compressor unit in oxygen plant

Non-ferrous metallurgy energy saving â–¡ equipment energy saving on -W equipment energy saving I, Han oxygen plant spoke air compressor unit noise control measures Wu Weiguo Yan Yanfei (Henan Yuguang Gold Lead Co., Ltd., Henan Jiyuan 454650) analyzed the turbine air compressor noise The resulting mechanism, treatment plan and effect.

Turbine air compressor; noise; a company's oxygen station is equipped with a single-axis air turbine compressor unit manufactured by Hangyang Turbine Machinery Co., Ltd., which consists of synchronous motor, speed increaser, coupling, machine body and cooling. Composition. Parameters: Power 0.6MPa. When the turbine air compressor is running, it measures up to 116dB of harsh noise from the machine and pipeline at 1m. The sound level is high, the low frequency is prominent, the propagation distance is long, and the pollution range is large, which makes people feel dizzy and nausea. Symptoms such as rapid heart rate, high blood pressure, etc. directly pose a hazard to the physical and mental health of workers in the job position. To this end, the air compressor compressor of the oxygen station is subjected to sound insulation and noise reduction, and good results have been achieved.

1 Turbine air compressor unit produces noise mechanism (1) Dynamic noise. The turbo air compressor is a centrifugal high-speed rotating mechanical device. After the air enters, the blade (impeller) periodically strikes the air mass point to generate noise caused by eddy current, impact or air flow disturbance caused by sudden change of pressure (load). It is related to the speed of the air compressor, the shape of the impeller, the size and shape of the intake and exhaust pipes. When the impeller is operated under a certain pressure condition, it periodically strikes the gas molecules, causing the gas around the impeller to generate velocity pressure pulsation and radiating in the form of sound waves, thus forming a rotating sound; while the impeller rotates at a high speed while on its surface A large amount of gas vortex is formed, and when these gas vortices are separated at the impeller interface, turbine noise is generated. The superposition and mixing of these noises forms aerodynamic noise.

(2) Mechanical operation noise. It is impossible to absolutely balance the moving equipment at high speed. Therefore, direct contact between mechanical parts (such as bearings and gears) in the machine generates shock vibration and friction noise, so mechanical noise is formed.

(3) Import and export pipeline noise. The noise generated by various mechanical rotating devices propagates not only around the body but also along the airflow (forward and reverse) of the inlet and outlet pipes connected to it. For example, the airflow from the air compressor inlet and the air compressor stage to the gas cooler inlet and outlet area noise.

(4) Electromagnetic noise. In the synchronous motor, an alternating magnetic field is formed when the rotor moves along the cutting magnetic field of the stator, thereby causing vibration of the housing and the core and other related components to generate noise.

2 Noise control scheme has great relationship with dynamic noise and mechanical running noise, and manufacturer's product design, processing and assembly process and gap control during installation. Therefore, the air compressor noise control after the commissioning of the main oxygen plant turbine air compressor unit noise control measures Wu Weiguo Yan Yanfei push the wind muffler into the wind, the elevation of 5 meters platform layout plan to reduce the noise radiation area, avoid sound insulation cover and the body Resonance, with a softer elastic material between the bottom of the sound enclosure and the ground.

(2) Reasonable lighting. In order to ensure the lighting effect, set the double open diaphragm door M1 fan, double plexiglass sound insulation window C750X 750mm four. At the same time, the interior adopts ceiling-mounted, waterproof and explosion-proof lamps with protective cover. The illumination brightness is not less than 85Lex, and it is equipped with air-opening, control box and other electrical appliances. The control system is installed outside the cover.

(3) Ensure good ventilation and heat dissipation. A ventilation method that combines forced air intake with natural air intake and forced air exhaust. The upper three sets of -11-7.1 type fan exhaust hot air, the lower part of the cold air ventilation system. The fan is controlled by semi-automatic electronic control to ensure ventilation. In order to reduce secondary noise generated by the fan and prevent noise from being transmitted from the air inlet and the air outlet, a muffler in the form of a circular arc resistive structure is installed at the inlet and outlet, and the muffler is closely attached to the wall of the sound insulation cover. An automatic constant temperature adjustment system is installed in the hood to make the internal and external temperature difference <5*C. (4) The condenser part, the intake and exhaust pipes are sound-insulated and silenced. The air compressor unit is arranged as an island. The original platform and the column are used, and the sound insulation cover is also installed on the condenser. The air inlet and exhaust pipes of the air compressor are damped and sound-damped by sound absorbing materials and flexible materials to eliminate the pipeline transmission noise. As shown.

Elevation 0 m floor plan (down to page 35) If the air compressor body, motor and inlet and outlet pipes, in combination with the machine's heat dissipation, ventilation operation, maintenance and inspection lighting, etc. without affecting oxygen production The following schemes are formulated for the air compressor sound insulation cover: (1) The large sound insulation cover is used for the body to be closed, which is convenient for maintenance and strength. Due to the large compressor, the acoustic enclosure dimensions are shown in 12 1 . The whole module is assembled and assembled. When the pipe passes through the sound insulation cover, holes need to be reserved. Two modules are used to fasten the structure. The other modules are bolted, detachable and avoiding the fire. Square steel is used as the main column on both sides of the module. In order to ensure the sealing between the module and the module, a sealing material is adhered between the square steel and the square steel to avoid rigid connection. The outer wall of the module is made of 2mm cold-rolled steel plate, the inner cover is perforated galvanized or aluminum plate, and the middle frame is made of U-shaped channel steel. The module has a thickness of 150mm and a composite filling method with different capacities inside, which widens the sound absorption band and increases the sound absorption effect, and avoids the sedimentation of the sound absorbing material. The module is rust-proof and anti-corrosive to improve its anti-corrosion performance and aesthetics. At the same time, in order to ensure its stability and safety, the wind pressure resistance value, explosion-proof uniform load, etc. must meet the strength synchronization motor coupling 2 door coupling 1 disease 9 hanging conveyor chain unsynchronized phenomenon transformation and analysis of a week of Xiongbin, The inverter can smoothly increase or decrease the original set frequency. The frequency increase or decrease is determined by the length of time the jumper is turned on. The longer the jumper is turned on, the more the amount of reduction or increase is. The shorter the line turn-on time, the less the amount of reduction or increase. The role of the PLC is to control the length of time the jumper is turned on.

For the PLC to automatically adjust the program flow chart to the inverter, when the chain moves, the PLC records the running time. When the chain reaches the end point, the PLC compares the chain running time 7\ with the set time T. When 7\>T, the Ti value Subtracting with T, the deviation values ​​A and Ati are compared with the set deviation amount At. When greater than At, the PLC output satisfies the acceleration adjustment signal; when Ti=T, the PLC does not adjust the inverter; The PLC program instructions of the automatic adjustment section are shown in Table 2.

4 Conclusion After the transformation of the automatic correction control of the unbalanced deviation by PLC and inverter, the bilateral chain is not synchronized due to various mechanical wear or permanent elongation of the chain during use, in the event of misalignment, it is possible Under the automatic correction measure, the entire calibration process takes only ten seconds, and the laborious and continually adjusted heavy work required by the original is eliminated, and the stability of the equipment operation is improved.

However, the modification is still limited to a small degree of mechanical wear and a small amount of permanent tensile elongation of the chain. When the mechanical wear and the permanent stretching of the chain reach a certain level, in order to ensure the safety and stability of the operation of the equipment, other corresponding needs are still needed. Treatment measures.

Table 2 PLC program command in the automatic adjustment part of the chain operation = 接近 接近 proximity switch output = chain 丨 arrival limit * comparison time value and reference value * cone value minus running time value * running time value minus reference value, Output to offset set r>2 register * bias value comparison comparison = chain 丨 arrival limit = chain 2 arrival limit = chain 1M first arrival delay = chain 1 arrival limit = chain 2 arrival limit = chain 2 most First arrival delay = chain 1M first arrival delay = after the delay reaches the condition, close the inverter deceleration jumper (on page 3i). After the implementation of the treatment effect scheme, the noise of the turbine air compressor unit is significantly reduced. Before the treatment, the noise of the air compressor is 6dB, and the bottom cooler is i20dB. After treatment, it is 83dB and 85dB respectively. It conforms to the national standard "Industrial Enterprise Noise Control Design Specification" (GBJ87*i985) and 4 Conclusions Control Air Separation Noise is the designer. Issues that should be fully considered by the operator. In addition to the design of the surrounding environment and equipment, the operator should also be equipped with protective equipment such as earplugs. Noise control is a systematic project. Therefore, the management of various sound source equipment should adopt reasonable and appropriate control and control measures according to the spectral characteristics of noise. It should be comprehensively considered and comprehensively analyzed to achieve technically advanced and economically reasonable. Meet the requirements of environmental and labor regulations.

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