Gas generators fully utilize various gases or harmful gases as fuel, converting waste into treasure, ensuring safe and convenient operation, offering high cost-effectiveness, low emissions, and being suitable for combined heat and power production, etc., with a promising market prospect.
China boasts abundant natural gas resources. In comparison to the country's vast natural gas reserves, the proportion of natural gas in China's primary energy consumption is relatively small, indicating significant potential for substantial growth in the future.
In China, due to the influence of gas supply, gas power generation is still in its infancy. Large-scale gas power generation as distributed energy stations is still a ways off. Small-scale gas power generation is primarily found in oil fields, gas fields, and at airports, hotels, and other locations. It is expected that with increasingly abundant gas supply and expanding supply areas, gas power generation will see rapid development in the coming years.
Advantages:
The gas generator set boasts a wide power output range, reliable start-up and operation, high-quality electricity generation, light weight, compact size, simple maintenance, and low-frequency noise. Generally, they have the following four advantages:
Good power generation quality
Due to the generator set's operation involving only rotational movement, the electronic control responds quickly, ensuring exceptional stability. The generator's output voltage and frequency are highly precise with minimal fluctuations. The set operates extremely stably during sudden 50% and 75% load changes, outperforming the electrical performance specifications of diesel generator sets.
Good start-up performance, high start-up success rate
The time from cold start to full load is only 30 seconds, whereas international regulations stipulate that diesel generators must be loaded within 3 minutes of successful start-up. Gas turbine generator sets can ensure successful start-ups under any environmental temperature and climate conditions.
Low noise and minimal vibration
Due to the gas turbine's high-speed rotation, its vibration is minimal, and its low-frequency noise is superior to that of diesel generator sets.
Four, the combustible gas used is a clean, inexpensive energy source.
Such as gas, Platycodon gas, etc., power generation sets fueled by them are not only reliable in operation and cost-effective, but also turn waste into treasure without causing pollution.
Noise Abatement:
The gas-powered generator set consists of components such as a gas engine, generator, and control cabinet, all mounted on a single steel chassis. The set runs on combustible gases like natural gas, associated gas from oil wells, coal mine methane, water gas, refining by-products, coke oven gas, and blast furnace gas, offering quick startup and good economy. Particularly due to the demand for high-quality urban living, gas generator sets are widely used as backup power sources in telecommunications, post offices, banks, libraries, hotels, and other departments. Early gas generator sets were designed for mine conditions, with operating noise typically ranging from 95 to 110 dB(A). The GB 3096-93 urban area environmental noise standard strictly regulates noise levels in urban areas, with daytime noise levels for Category 2 areas (residential, commercial, and industrial mixed zones) at 60 dB(A) and nighttime at 50 dB(A), and for Category 1 areas (residential and cultural and educational institutions) at 55 dB(A) during the day and 45 dB(A) at night. The noise produced by the operation of the sets poses serious noise pollution to urban environments, affecting people's normal work and life, and limiting the widespread application of gas generator sets. This article proposes a set of rectification measures to reduce the noise of the sets and promote their wider use.
1. Source Analysis
Gasoline engine noise is the primary source of noise in gas generator sets, which can be categorized into aerodynamic noise, combustion noise, mechanical noise, exhaust noise, and vibration noise. Aerodynamic noise primarily includes air vibration noise caused by intake and exhaust as well as fan rotation, which directly spreads into the air. The pressure vibration formed by combustion inside the cylinder, radiating outward through the cylinder head and body, is called combustion noise; the impact noise produced by the piston hitting the cylinder sleeve, as well as the impact vibrations from moving parts like the valve train and injection system, is collectively termed mechanical noise. During operation, exhaust gases are expelled at high speed through the exhaust valve, entering the muffler via the exhaust manifold, and finally released into the atmosphere through the tailpipe. Exhaust noise is the main noise source of the engine, typically around 15 dB(A) louder than the engine's main noise, followed by combustion noise, mechanical noise, fan noise, and intake noise.
2. Modified Design
Based on the operating principle of gas power generators, it's difficult to reduce the noise source's noise using noise attenuation methods, so the primary approach is to effectively block its noise transmission paths. The core of noise attenuation technology is to utilize the natural attenuation law of sound waves during propagation to reduce the scope of noise pollution. Specific methods to reduce noise include: absorption, insulation, and altering the noise transmission direction. In practical engineering applications, usually only one of these methods is employed. This paper adopts a combined approach using all three methods and proposes a new integrated noise reduction technology for gas power generators.
(1) Combination muffler
The original silencer primarily relied on resistive noise reduction, consuming high power with suboptimal noise reduction. After careful consideration, it has been upgraded to a new combined silencer using three-stage noise reduction technology. The main components of this combined silencer include the spray noise reduction and vibration damping chamber, porous noise reduction housing, sound-absorbing and insulating layer, and sound-absorbing resonant plates. The noise energy from mid-to-low frequency sources is effectively dissipated resistively as it passes through the spray noise reduction and vibration damping chamber of the first stage. The second stage's porous resistive noise reduction housing eliminates most high-frequency noise, enhancing the silencer's adaptability to high frequencies. It also contains sound-absorbing material, which fully absorbs and redirects noise, further dissipating noise energy. The third stage features a specially designed exhaust pipe with resonant plates, further reducing noise through the vibration of thin plates. Tests have shown that the new silencer outperforms the original in noise reduction level, frequency range of noise reduction (mainly the frequency range of the noise reduction peak), and resistance loss. Additionally, the silencer is appropriately sized, has good structural rigidity, is easy to install, and has the function of suppressing regenerative noise. The rear sound-absorbing and insulating layer also has corrosion resistance, effectively overcoming low-temperature dew point corrosion of smoke gases, thereby extending the service life of the silencer.
(2) Two-stage Vibration Damping Pad
Effective methods for controlling mechanical and combustion noise involve vibration isolation for the equipment. Composite vibration-damping pads are installed between the gas engine, generator, and steel chassis, as well as high-efficiency vibration-damping rubber pads between the chassis and the foundation. After two-stage vibration isolation, not only is the vibration of the equipment effectively isolated, but the operation of the equipment becomes more stable, and the overall noise is significantly reduced.
(3) Noise-reducing exhaust duct
Fan noise is composed of rotational noise and vortex noise. Rotational noise is caused by the periodic disturbances generated when the rotating fan blades cut through the airflow. Vortex noise is a series of swirling flows that form due to boundary layer separation on the cross-section of the rotating blades, resulting from gas slip or separation, radiating a non-stable flow noise. The exhaust duct is directly connected to the outside, with a high air velocity, and the noise from the airflow, fan, and mechanical sources is radiated through this channel. To control the noise from the fan and exhaust duct, a silencing exhaust duct has been designed. This silencing exhaust duct is relatively long and consists of a guiding slot and an exhaust noise reduction chamber. The working principle of the exhaust noise reduction chamber is similar to that of a resistive silencer. The noise reduction effect can be improved by changing the parameters such as the thickness of the sound-absorbing material (altering the sound absorption coefficient of the material), the length and width of the exhaust duct, etc.
(4) Silencer Inlet Duct
The unit operates within an enclosed room. Broadly speaking, the intake system encompasses the unit's air intake ducts and the engine's intake system. Both the intake and exhaust ducts are directly connected to the outside, with high air flow rates, resulting in noise from both the air flow and the unit's operation being radiated outside. The noise from the engine's intake system is generated by pressure fluctuations caused by the periodic opening and closing of the intake valves, with the noise frequency typically in the low-frequency range below 500 Hz. Two silencing intake ducts are installed on the room walls, serving as both the room's intake and the engine's intake. Due to the negative pressure caused by exhaust, cool air naturally enters the room through the silencing intake ducts, expelling the heat emitted by the unit. This ensures there is sufficient fresh air within the room.
