dear shenjie,

A quick design for a dilute phase conveying installation is:

compressor 1.72 m3/sec (103 m3/min)

conveying pressiure 2.5 bar(o)

pipeline dia first 2/3 of length = 16 "

pipeline dia last 1/3 of length = 18"

capacity calculated = 300 tons fly-ash/hr

loading ratio = 39.06

I think that the lowest investment will still be a lot of money.

But a economical study will show, whether it is expensive or cheap (feasible)

have a nice day ■

Dear Mr Tuinenburg

Very Interesting cals. are you sure this is a lean phase system? 11m/s exit velocity and SLR of 40 sounds more like a dense phase to me. ■

dear shenjie,

I did not include a rotary lock in my calculation.

A rotary lock should be a 500 mm diam one at approx. 15 rpm

But the rotary lock will leak abt .53 m3/sec of convey air.

Therefore the air pump must be 2.3 m3/sec

at 2.5 bar(o), which consumes already 500 kw at 2.5 bar

This results in 1.64 kWh/ton

The rotary lock can cause a lot of operational problems.

It has to cope with fine and abrasive material agains a pressure difference of at least 2.5 to 3.0 bar.

The rotary leakage can also influence the filling efficiency of the rotary lock, causing pluctuating preformance.

dear Mr Mantoo,

Volume wise, it is lean phase, approx 17.3% of the volume at the beginning of the pipeline is occupied by the fly ash.

but the definition of dilute or dense phase is the Zenz diagram.

Left of the lowest pressure drop/m is dense phase and right of the lowest point is dilute phase.

If I increase the air flow from 1.72 m3/sec (old calculation) to 1.85 m3/sec then the pressure drop decrease to 2.3857 bar.

This corresponds with your opinion.

But is it an important conclusion ? I calculate always with the same algorithm, whether it is dense or dilute.

Nevertheless, I agree : very interesting

best regards ■

dear shenjie,

the energy consumption is:

1.64 kWh/conveyed ton for the total of 500 mtrs of pipeline

I don't that I can come up with other (better) solutions, although that does not meant that better solutions are possible.

Input from other members is needed.

have a nice day. ■

Dear Teus ,we all know that you are very kind and warmhearted, so can you explain how to caculate your following result.especially ,i eager to know how you decide the position (2/3)where to increase the bore of pipe!

BR

■

Dear Teus ,we all know that you are very kindness, so can you explain how to caculate your following result.especially ,i eager to know how you decide the position (2/3)where to increase the bore of pipe!

■

Dear Jim Lee,

As I said, this is a quick design.

That means that I feed my calculation program only with the design main parameters.

-Capacity

-horizontal length

-vertical length

-number of bends

-single pipeline diameter or stepped pipe line diameter.

-material

Then the computer calculates, as a PRELIMINARY DESIGN, the required air volume at 2.5 bar(o) and the pipe line diameters.

The location for the step in the pipeline is assumed at 2/3 of the convey length as a possible location.

If the design becomes a real project, then that step location is determined exactly by the sedimentation criterion.

If the diameter increases too soon, the velocity after the step becomes too low (sedimentation) and if too late, then unnecessary energy is wasted.

success ■