Re: Wet Fly Ash Handling
It would be better to collect the fly ash directly from the filters/precipitators. Then the correct particle sizes can be easily screened.
If you must reclaim from the lagoon then at some point you're going to have to dry the ash. ■
Keep Yer Powder Dry & Wait Till You See The Whites Of Their Eye…
Some books say 20-22 degrees. If the ash is conditioned on its way to the lagoon then it will need the same final conditioned state, 50-65% water, for conveyance to the mill. How did it get so wet?
Yours is the sad old tale of the power companies good intention to sell the fly ash but then realising that they really meant "eventually", whenever that might be, so they have to dump it anyway.
Designer is quite right. To appreciate his argument just visit the website, on these forums, for a UK operation which transports the dry ash from the power station to the batching plant in fluidising tank containers carried by a railroad operator. 
It's the only viable operation that I've seen to emerge from the good intentions brigade. Pity their sales operation is so indolent. 
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Wet Flyash Handling
Hello Calvin,
As I come from quite the same point / same question, so some input could be:
The addition of water is surely aimed at cooling and dust suppression, but is this extent necessary? Is it simply the way it is currently done?
If not, mixing should be in a way that the final product remains sufficiently stout to be conveyed by a belt.
Let the properties of this mixture be checked / determined by some specialist. There is some percentage points with sudden changes in the conveying properties of the product --> So conveying characteristics (possible angle of incline etc.) emerge from defined water contents.
My op is: At this moisture content (50%+) it is some kind of sludge that is rather difficult to convey by belt conveyor, esp. upwards, but then imagine the way down. I don't think that this sludge can properly pass any conventional belt tranfer point.
But if you abandon the belt conveying, there's perhaps some pump & pipe solution for a 50%+ mixture.
I'd like to have news of your final approach / any sparky ideas!
Best wishes
Roland ■
Re: Wet Fly Ash Handling
The kind of moisture content ash that you refer to we pump as a slurry to our ash dams at our "wet" power stations at Eskom in South Africa. At the "dry" stations fly ash is conditioned to a moisture content of avg. 15% and conveyed by conventional flat belt conveyor to an Ash Dump.
Regards
Henk ■
Re: Wet Fly Ash Handling
Hi Henk..
We handled alot of wet stuff at Rossing as well as at Namakwa Sands
Neither of these belts are protected from the rain, and at times we handle sand and tails at totally saturated moisture contents from downpours.
After a severe rainstorm I started an overland system at well over 50% moisture. It all went through the system, which ended by going up a conveyor at 16 degrees.
It appears to flow backwards, but not as fast as it is going forwards, if you get what I mean.
Therefore the belt speed has to be fast enough to well exceed the flow back.
Here the belt speed was 3.5m/sec up the 16 degrees, so this will give you an indication.
The amazing thing was that we didn't have much spillage at the transfers, and the dead boxes were completely washed clean out.
(Heavens knows what would happen if you have a trip out when operating like this though)
Cheers
LSL Tekpro ■
Re: Wet Fly Ash Handling
Originally Posted by Graham Spriggs
...
It appears to flow backwards, but not as fast as it is going forwards, if you get what I mean.
...
The amazing thing was that we didn't have much spillage at the transfers, and the dead boxes were completely washed clean out.
(Heavens knows what would happen if you have a trip out when operating like this though)
Cheers
LSL Tekpro
Graham,
Thanks for the input. It sounds fascinating and, as you say, amazing that the dead boxes got rinsed out.
If I watch a lava flow on the TV I get mesmerized by the flow patterns. Is the 'appears to flow backwards but not as fast as it is going forwards' something similar in appearance? ■
Re: Wet Fly Ash Handling
Its actually more like Michael Jackson doing his moon walk!
Cheers
LSL Tekpro ■
Wet Fly Ash Handling
I need to convey wet fly ash (50-65% moisture) which is produced by coal-fired power plant and the ashis dumped into ash lagoon for storage.
We use it to produce cement.
I want to use belt conveyor to transport it to feed to mill. Could anyone suggest how large the belt can be inclined? or any comment on this handling approach? ■