Noise reduction design of oil and gas field long-distance pipeline compressor plant
Compressor plant; sound absorption; sound insulation; noise reduction fund project: China National Petroleum Corporation key project funding project (S2008-4E) Peng Yu (1979-), male, Sichuan Suining, engineer, bachelor, mainly engaged in natural gas construction Design work.
0刖In the architectural design of the compressor plant of Yulin Compressing Station of the second line of Shaanxi-Beijing, the environmental noise-reducing sandwich panel (also known as flat-type muffler) is used for building noise reduction. According to the measured results, the noise in the workshop does not exceed 90dB, and the noise value at the boundary of the plant does not exceed 65dB during the day, which meets the requirements of relevant national regulations. After the completion of the actual use, the effect is better, and it has been affirmed by the users and the industry.
1 Noise reduction target The plane size of the compressor building of the Yulin Compressor Station of the second line of Shaanxi-Beijing Railway is 48mx24m. Two compressors are placed side by side. The noise value of the compressor during single operation is about 115dB. The target value of noise reduction is: The noise in the compressor building is controlled at 90dB; the integrated noise reduction in the compressor building is not less than 20dB; the noise control at the plant boundary is 65dB in the daytime, and the noise reduction design of the compressor unit at night 2 is 2.1. Structural selection Since the 1990s, domestic The development of outer steel structure is very rapid, especially the light steel structure is more rapid in the construction and application of industrial plants. The compressor building of this structure usually adopts H-shaped steel as the beam and column, and uses C-shaped or Z-shaped light steel as the purlin. The roof and wall cladding adopts a single-layer or sandwich-type profiled steel plate. The interior of the sandwich panel is filled with rock wool, glass wool and other insulation layers. Because of its short construction period, strong adaptability, beautiful appearance and easy maintenance, it is domestic. The development is very fast. However, in terms of noise reduction effect, the ordinary light steel structure compressor factory only sins very thin (thickness 0.5~0.8mm) inside and outside color steel plate to achieve sound insulation purposes, the integrated sound insulation noise reduction is only 10~15dB (A) That is to use the method of thickening the core material to improve the noise reduction of the ordinary color plate structure, and the effect is very small, and it is impossible to effectively isolate and reduce the noise of the high-intensity industrial noise generated during the operation of the compressor. Comprehensive consideration, the design of the compressor plant uses new exterior wall materials, and isolates the wind environmental protection machine from the compressor unit, and sets up a fully enclosed fan room at the two corners of the plant, which can effectively reduce the reverberation noise of the fan and compressor.
2.2 Principle of Noise Reduction For many years, the failure to achieve environmental standards for ordinary light steel structure compressor plants has been a major issue that has plagued the environmental protection industry. When the natural gas compressor unit is running, it will produce wide-band high-intensity industrial noise. With single-noise reduction technology, it is impossible to achieve noise reduction in complex working conditions. It is necessary to efficiently combine noise reduction, sound insulation, damping and vibration reduction technologies. Achieve efficient noise reduction in natural gas compressor plants. The environmentally-friendly thermal insulation and noise reduction sandwich panel is based on this theory. After several years of research and practice, the advanced integrated noise reduction technology is applied to the structure of the ordinary light steel structure compressor plant, providing environmental protection standards. Strong protection. The principle of noise reduction is: sound absorption refers to the phenomenon of energy loss after the sound wave hits the surface of the material. The principle of sound absorption is that the sound wave penetrates into the interior of the material along the internal pores of the material, and the friction energy acts to convert the sound energy into heat energy. Therefore, the sound absorbing materials have a large number of pores, and the pores are connected to each other, such as centrifugal glass wool, rock wool, mineral wool, plant fibers and the like.
Sound insulation refers to the phenomenon that sound waves are isolated or blocked by materials. The principle of sound insulation is to use a dense material to attenuate the transmission of sound energy, thereby blocking the propagation of sound. Therefore, the sound insulation material cannot be as porous, loose and breathable as the sound absorbing material. On the contrary, its material should be heavy and dense, such as steel plates, lead plates, brick walls and the like.
The difference between material sound absorption and material sound insulation is that the material sound absorption focuses on the sound energy reflected from the sound source side, and the target is that the reflected sound energy is small.
The material sound insulation focuses on the amount of transmitted sound energy on the other side of the incident sound source, and the target is that the transmitted sound energy is small. The sound absorbing ability is generally expressed by the sound absorption coefficient, and the sound insulation ability is expressed by the sound insulation amount.
In the noise reduction design of the compressor plant, both indoor noise control and outdoor noise compliance are required, so good sound absorption and sound insulation materials must be selected. In the engineering, the noise reduction coefficient NRC is often used to roughly evaluate the sound absorption performance in the language frequency range. Generally, the material of NRO0.2 is considered to be a sound absorbing material, the material of NRC<0.2 is a reflective material, and most of the reflective material is used. In the sound insulation. For example, a 5cm thick 24kg/m3 centrifugal glass wool can achieve a NRC of 0.95, which is a very good sound absorbing material; while a 3mm thick 7.8g/cm3 steel plate has a sound insulation of about 25dB, which is a good sound insulation. material. The environmentally-friendly thermal noise reduction sandwich panels used in this noise reduction design also make good use of the good sound absorption and sound insulation properties of these two materials.
See the construction of environmentally friendly thermal insulation and noise reduction sandwich panels.
The environmentally-friendly thermal insulation and noise reduction sandwich panel is composed of the following materials (from the inside to the outside): aluminum orifice plate, centrifugal glass wool, damping rubber and steel plate.
The functions of each component and the principle of noise reduction are as follows: Aluminum orifice plate: This layer is the structural layer of environmentally-friendly thermal insulation noise reduction sandwich panel, which mainly supports and fixes centrifugal glass wool, and 15% perforation rate ensures noise. Through the sound hole of the board, the core noise reduction layer of the environmentally-friendly thermal noise reduction sandwich panel is transmitted.
Centrifugal glass wool: It is an ultra-fine glass fiber with a noise reduction coefficient of more than 0.95. It is one of the core noise-reducing layers of the environmentally-friendly thermal insulation and noise reduction sandwich panel, which mainly plays the role of sound absorption. When high-intensity industrial noise passes through the aluminum orifice plate, the sound and material friction, the sound energy is converted into heat energy, and the sound energy is greatly attenuated.
Damping glue: Damping glue is a good heat-insulating and damping adhesive. It mainly plays a bonding role between centrifugal glass wool and steel plate. At the same time, it can weaken the steel plate and centrifugal glass caused by noise because of its good vibration damping performance. The vibration of cotton plays a role in damping and noise reduction.
Steel plate: The steel plate with a thickness of 3mm mainly acts as a sound insulation layer, and is also the core noise reduction layer of the flat muffler. The heavy and dense material characteristics make the sound insulation amount reach about 25dB, which is the environmentally-friendly thermal insulation noise reduction sandwich panel for noise reduction. The last barrier is also the key material for industrial noise emissions.
Another major feature of the technology is that it avoids noise reverberation indoors. In the ordinary compressor factory, the sound emitted by the noise source will be reflected when it encounters the wall or the roof. When the compressor is running, in addition to the direct noise, the reflected sound formed by the back and forth reflection of these surfaces can be heard, that is, the reverberation sound, so the general indoor noise is 3~5dB higher than the outdoor noise. The perforation type is adopted, and each hole and the air layer volume occupied by the back form a resonance sound absorber, and then enter the comprehensive noise reduction body sound absorption and noise reduction layer for sound absorption and noise reduction, which can greatly reduce the reverberation sound and comprehensively absorb sound drop. The noise value can reach 3~5dB(A), which effectively protects the physical and mental health of the staff.
Taking into account the economics of the construction of the plant, as well as the wall and roof as a venting measure, the weight per square meter of the wall is controlled in the design, which limits the thickness of the steel plate as the sound insulating material, and makes the environmentally friendly type The noise reduction effect of the thermal insulation noise reduction sandwich panel can only meet the national requirements for the discharge of the standard and can not completely eliminate the noise of the external transmission.
2.3 Special measures fundamentally control the noise source in the room. The noise of the compressor under normal working conditions is about 115dB. If no measures are taken, the noise reduction effect of the flat muffler can neither reach the standard discharge nor give the indoor operator. The body damage is caused, so the compressor of the Yulin Compressor Station project has a soundproof cover, so that the noise in the room is controlled in the reasonable design of the doors and windows of the compressor building. As we all know, doors and windows are an important path for noise to spread out. In the design of the compressor plant of Yulin Compressor Station, there are no windows on the wall, only the lighting belt is set on the factory floor (ventilation design is forced mechanical ventilation); the gate of the factory and The small door adopts the sound insulation door, and the noise reduction value of the sound insulation is 20~25dB. 3 Application effect 3.1 Specification requirements The noise control design specification of GB87-85 industrial enterprise stipulates that the noise of the production workshop and work place does not exceed 90dB (continuous contact every day) Noise 8h), the noise value at the boundary of the plant is not more than 65dB during the day and 55dB at night. 3.2 Measurement data 3.2.1 The single measuring unit of the compressor plant is used for one compressor and two compressor units. The measured noise values ​​are not More than 90dB. Measured from the distance of 1m from the outer wall of the plant, the measured noise value is less than 82dB, see the measurement point and value. The noise values ​​measured outside the factory are measured under the condition of external noise, and the measured values ​​do not completely represent the noise generated by the compressor building. After the operator's understanding, except for the maintenance day, the daily operation time of the operator in the factory is only 0.5h. According to the specification of Table 2.0.1 of the GB87-85 industrial enterprise noise control design specification: the worker is exposed to insufficient noise every day. In the case of 8h, the noise limit value can be determined according to the actual contact noise time and the principle that the contact time is reduced by half the noise limit value by 3dB. Therefore, according to the actual situation, the noise limit value of the compressor building of Yulin Compressor Station can be increased to 102dB. It can be seen from the actual measured data at the site that the noise reduction measures of the compressor building can meet the design requirements. Whether the design requirements of the two compressors in the plant can be tested at the same time is yet to be tested.
(Continued on page 98) 3.2.2 Equipment Noise Measurement The boundary noise is the integrated noise generated by various equipments, not only the noise generated by the compressor building alone. In addition to the compressor building, there are air coolers and oil coolers. See the noise value measured by the air cooler 1m, the noise value measured by the oil cooler 1m is 81.8dB.
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