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Pneumatic Ash Handling System
Alstom Sizhou pneumatic ash handling system has been servicing for more than 100 heat
supply & power generation units until now, accumulating abundant experience. We
recruited pneumatic conveying expert Mr. MIKE.SALTER as chief engineer of pneumatic
conveying department in 2007, which further promotes us to a leading status in the same
industry.
Advantages of pneumatic conveying
Environmentally friendly
Enclosed pipe work minimises dust emissions
Minimal maintenance
Less moving parts
Flexible construction
Systems upgrading easily at a later date
Simple installation
Good adaptability for various client’s fields layouts
Three basic modes of conveying
Lean-Phase - the oldest method
High volumes of low pressure air entrain material in a high velocity air stream
Entrains individual particles in a high velocity air flow (15 - 30 m/sec) necessary to pick up the mass of the particles
Can either be positive pressure or vacuum
Pipe diameters must be large to achieve reasonable transfer rates up to 150 - 200 metres
Component and pipe wear is very high because of the high transfer velocities - special wear-high resistant materials must be used
Energy consumption is high as the air source runs continuously regardless of transfer rate requirements
Silo filtration is generally large and complicated
Medium-phase
Use higher air pressures to convey material over longer distances at lower velocities
Material travels in a moving mass in the pipe base
Velocity must be high enough to avoid blocking the pipeline with material - typically 5 to 15 m/sec
Usually positive pressure < 2.5 bar(g)
Handles dry, homogenous fluidisable materials over distances up to 2,000 metres
Pipes are generally smaller than for lean-phase
Pipe wear can be a problem if not designed & installed correctly
Control of material flow into the pipeline is critical
Dense-Phase - a more modern technology
A controlled use of both air pressure and volume transfers material through the pipe in discrete plugs with pockets of compressed air in between Positive pressure conveying using medium pressure air > 3.0 bar (g)
Much lower Velocity at 1.5 to 10.0 m/sec reducing much pipe wear
Adaptable for a wide range of dry materials; fly ash conveying distance could be up to 1000 metres
Pipes are much smaller than for lean-phase
Low energy consumption, air supplied only required for conveying materials (Normally energy cost is proportional to the real conveying ash-air ratio)
Why choose dense-phase?
Pipe savings
Smaller diameter, lower cost conveying pipes
Less wear means piping system lasts longer
Standard steel pipes with wear resistant bends
Maintenance savings
Less wear & reduced equipment offers 50% - 80% savings in Spare Parts and Maintenance Costs
Standard compressed air requirements
Common for multiple installations
More easily obtained for compressors
Less spare parts required
Energy savings ~ 30% - 50% reduction in real costs
Automatic control and regulation of compressed air use, compressed air supplied as per required.
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