Bottom ash conveyor design change
Bottom ash conveyor design change
(OP)
There is some talk about replacing our submerged ash drag chain conveyor with a dry bottom screw conveyor. Our plant is a stoker fired wood waste boiler. Does anyone have any experience with this design. I was trying to do some research on the internet and have yet to find any bottom ash conveyor manufacturers to use a screw design for this type of application.





RE: Bottom ash conveyor design change
I have played around with both, and prefer the wet bottom with drag chain (or belt). The things to watch for with a screw are bridging avoidance, bearing protection and gas sealing.
With low ash (no bark or mud) you may get away with a screw; I still use them on coal fired economic boiler refits, but much prefer wet handling if only to avoid the screeching of dry screws. If you go for a live base multiple screw arrangement with the screws supported at both ends dropping into a trough then you may have a winner. But there would have to be a good reason to do it, such as a flyash baghouse and pneumatically handled interpass deashing arrangement.
Also screws do not handle clinker as well as a drag chain.
Cheers
Steve
RE: Bottom ash conveyor design change
I haven't seen it done that way, but I have only seen 5-6 dozen wood fired boilers in my life, so my experience might be too limited.
I wouldn't do it.
rmw