Hi there..

50% moisture is somewhat high.

We do alot of powerstation ash handling plants and there the boiler bottom ash (coarse ash) is 45% moisture, and the precipitated fly ash is dry.

We condition the fly ash with water in a mixer to between 15 & 20% moisture and combine it with the wet coarse ash ratio 80%:20% (fly:coarse)

The bottom ash is pulled underwater in a drag trough under the boiler by a Submerged Scraper Conveyor (SSC). This pulls the ash first horizontally, then steeply up an incline which has de-watering herring-bone (chevron) grooves. The incline is steep and the lift is about 5m as you indicated.

Do not use pocket belts or buckets as the ash sticks to them.

There is however a bucket elevator which has holes in the buckets and for some reason I have seen it actually work.

I replaced a flexowell conveyor at a Brewery in Pretoria which used to try and convey wet coarse ash from thier boiler. It was hopeless, and finally collapsed.

I replaced it with a single fairly large winch driven skip hoist.

I lined it with plastic UHMWPE and it works fine.

So use a drag trough scraper conveyor or a skip

Good luck

LSL Tekpro ■

This product will be quite obscene to handle. Mentioning slurry implies that the water must be retained for the downstream mixing operation. You cannot convey such stuff. Even the Putzmeister requires some degree of homogenity before it will work. You cannot pump it. It will dewater with chain conveying.

It would be speculatively possible to introduce it to the mixing tank at base level from a blow tank at the vessel wall. Then you would need a rubber lined pinch valve to check the feed. By the time you blow the slurry against the 5m head there would be no need for a mixer. Come to thinkof it; unelss the shaft was very thick there wouldn't even be any mixer there after a few shots.

Grahams skip hoisting would be the best system. ■

A screw conveyor "may" work here.

We used to make screw pumps for sewage lift stations, they were inclined at 35 degrees, ran quite quickly, and were large dia with a large centre tube with no intermediate hanger bearings. However your capacity is not stated and may be too small for this.

When the screws were installed, concrete was poured in at the bottom and the screw was used to grout the trough, so slurrries went up OK. To me most materials over 30% moisture tend to become slop when shaken.

Graham, I too have seen the elevator buckets with holes in the bottom, but in that application it was to let air into the bottom of the bucket so the fine powder material could be thrown out at the discharge. ■

Actually, at many power stations, especially the older ones, they do actually pump the coarse ash.

For this, there must be no large clinkers in it and the moisture is typically 50/50+ (mass/mass and not by volume).

LSL Tekpro ■

Exactly so Dick..

The drag trough scraper conveyor I mentioned earlier.. is an inclined chain conveyor.

Regards

LSL Tekpro ■

Originally Posted by Graham Spriggs

Hi there..

50% moisture is somewhat high.

We do alot of powerstation ash handling plants and there the boiler bottom ash (coarse ash) is 45% moisture, and the precipitated fly ash is dry.

We condition the fly ash with water in a mixer to between 15 & 20% moisture and combine it with the wet coarse ash ratio 80%:20% (fly:coarse)

The bottom ash is pulled underwater in a drag trough under the boiler by a Submerged Scraper Conveyor (SSC). This pulls the ash first horizontally, then steeply up an incline which has de-watering herring-bone (chevron) grooves. The incline is steep and the lift is about 5m as you indicated.

Do not use pocket belts or buckets as the ash sticks to them.

There is however a bucket elevator which has holes in the buckets and for some reason I have seen it actually work.

I replaced a flexowell conveyor at a Brewery in Pretoria which used to try and convey wet coarse ash from thier boiler. It was hopeless, and finally collapsed.

I replaced it with a single fairly large winch driven skip hoist.

I lined it with plastic UHMWPE and it works fine.

So use a drag trough scraper conveyor or a skip

Good luck

LSL Tekpro

Dear sir

We are bidding in several project for ash handling in india

In this respect , we are looking to have technical support in field of bottom ash handkling system

May i request you to inmtimate us how to go about

rahul.chaubey@flsmidth.com ■

Hello Guddu..

I suggest you contact the people who make the bottom ash chain systems. So go to

www.heko.com

Cheers

LSL Tekpro ■