The question is more complex. There are many airslides operating on "flyash" at 8 degrees but there are many which need more slope.

Unfortunately, flyash is not always flyash. The type of coal, the boiler operation. the efficiency of the economizer, bag house or ESP, etc all come into play.

Some flyash aerates very easily and retains it's fluidization and will flow nicely at less slopes than others.

There is new technology called Pneumatic Modulation Technology which actually brings the fluidizing air into the material as pulsating and varying frequencies which has shown to reduce the air volume requirements of old.

Fabric erosion can be mitigated by using wear resistant wire mesh over the fabric surface, especially at the inlets.

Airslides have been around since the mid 1950's and while some believe they are dinosaurs, we have been involved in many retrofits and optimizations to give longevity to a technology which is one of the most energy efficient ways to move bulk materials, ■

Thanks Jack,

Air slides are successfully used to reclaim dry product at the following sites

1 - Alcoa Kwinana, West Australia - silo reclaim and truck loading feeds

2 - Esperance Port, West Australia - under rail unleading hoppers to reclaim nickel product to feed ship loaders. I think these are running at 6 deg

3 - I believe they are fairly common in flat bottom silo reclamation ■

Not too many have experience with air slides handling fly ash. So we need to go back to basics.

1 - Air slides work like a launder. Air is blown up from a bottom duct through a porous fabric. This turns the particle stream into a fluid-bed stream. With dry particles they act like a liquid in a launder. In fact, you can do all your flow calculations on the basis of an equivalent liquid

2 - What are the velocities involved at 10 deg compared to 8 degrees?

3 - How will you compensate for the lower velocities? By providing a wider trough, or by packing a deeper bed of ash in the same tray?

4 - Can you source a stronger fabric to reduce erosion? ■