Tail gas treatment | generator exhaust related knowledge


Release time:

2022-08-09

The exhaust system of the generator set must collect the gas in the engine cylinder and discharge it as quickly and quietly as possible. It must minimize the back pressure, which will lead to horsepow

 
The exhaust system of the generator set must collect the gas in the engine cylinder and discharge it as quickly and quietly as possible. It must minimize the back pressure, which will lead to horsepower loss and temperature rise, thus shortening the service life of the engine.
 
There are several factors that affect the performance of the exhaust system. Building restrictions, noise control, condensation, vibration, heat dissipation, and building codes must be considered.
 
exhaust pipe
 
Each generator set must be equipped with its own exhaust system. Connecting or sharing exhaust ducts will increase the chances of smoke entering idle engines or equipment, exposing them to corrosive gases.
 
Specify Schedule 40 piping. Its heavy-duty structure can suppress vibration and resist the corrosion of condensate. To minimize the back pressure at the bend of the exhaust system, use a bend with a radius of at least one and a half times the diameter of the pipe for a 90 degree bend.
 
When the system is at operating temperature, the weight exerted by the exhaust pipe on the engine should not exceed 37 kg (60 pounds).
 
Flexible connections are needed to alleviate vibration fatigue of exhaust system components. They can also prevent vibration from spreading throughout the building and solve the problem of dislocation during installation.
 
Long pipelines need flexible connections to provide heating growth. For example, a 6m (20 foot) steel exhaust pipe will increase by 33mm (1.3 inches) when heated to 510 ° C (950 ° f) at 30 ° C (100 ° f). Similarly, pipe supports must also allow for heat growth.
 
Consider insulated piping. Burning one liter of fuel in a diesel engine can produce up to one liter of water vapor. Insulation helps to keep the exhaust gas in a gaseous state and reduces the heat radiated to the generator set room.
 
Install a long horizontal exhaust pipe away from the engine and tilt it down slightly. The drain valve shall be located at the lowest point of operation so that condensate can be discharged.
 
Consult your engine manufacturer or its dealer for the correct exhaust specification.
 
Silencer / silencer
 
When installed as close to the engine as possible, the silencer can provide the best sound attenuation and minimize pipe vibration. Like pipes, silencers shall be installed obliquely and equipped with condensate drains.
 
There are many grades of silencers to choose from. Since the noise level varies depending on the engine model, rating, and distance measured from the exhaust port, use engine manufacturer data and muffler performance data to ensure adequate silence for the application.
 
Building exhaust
 
The pipe shall be installed with a clearance of at least 229 mm (9 inches) from combustible materials. High temperature insulation or prefabricated insulation can be used above the pipe to prevent head radiation. Pipes passing through wooden walls or roofs require a single wall metal thimble shield 305 mm (12 inches) larger than the diameter of the exhaust pipe. The double wall metal sleeve must be 153 mm (6 inches) larger than the pipe diameter. Thimbles must comply with nfpa-110 and local building codes.
 
 
Both horizontal and vertical exhaust chimneys should extend above or away from the building. The direction of the horizontal pipe outlet should be away from the prevailing wind and cut at an angle of 30 to 45 degrees to reduce gas turbulence and the resulting noise. The vertical chimney needs a rain cap, which exerts a small back pressure and can be forcibly opened by exhaust. In all cases, the chimney should be away from the air inlet of the building.