Many boiler operations handle siftings hopper material (sometimes called “siftings ash”) on a stoker fired boiler manually or with their fly ash collection system.  Working with a single ash system to handle all the bottom and fly ash as one system can create an onslaught of equipment problems. A single ash system is complicated and requires extensive conveyors and chains, resulting in unreliable in operation.

Fortunately, an affordable and reliable solution is to keep these systems separate with a Submerged Bottom Ash Collection Conveyor with accompanying Submerged Shaftless Siftings Hopper Collection Screws.  This specially designed system operates very reliably for each of these two completely different types of material/ash and it can be implemented with minimal conveyors and drag chains.  Even if an operation already has an existing submerged drag chain conveyor, adding the Siftings Hopper Collection Screws may be a good option to improve efficiency.

For mills that handle sifting ash manually, dumping of the hoppers requires considerable effort and is potentially dangerous because the hoppers are under a positive pressure and the gas temperature inside is >300°F.  For these mills, a Submerged Bottom Ash Conveyor with accompanying Submerged Shaftless Screws is an affordable alternative that eliminates the need for seal valves at the hopper discharge. The slow moving screws (<3 rpm) are made of standard carbon steel which minimizes maintenance and upkeep.

For mills that collect siftings hopper material with their fly ash collection system, transferring to the fly ash collection often requires a cumbersome system to take the sifting ash to the back side of the boiler where the fly ash system is located.  These systems can often be unreliable and require multiple seal valves, multiple hopper collection conveyors and normally and extra 100+ feet long transfer conveyor.

Another problem these mills encounter with this system is that the siftings hopper material (rocks, sand, clinker, wood) does not work well in a fly ash system arrangement. When this material is mixed with the fly ash it requires the conveyors downstream to have a more complicated design such as dual strand drag chains verses single strand drag chain arrangements.  It also causes difficulties in the silo and conditioning system designs due to the solid particles entrained with the fly ash particles.

The best way to avoid these problems is to treat the sifting hopper material (siftings ash) as bottom ash and handle it separately from the fly ash on stoker boiler operation. Keeping these systems separate allows for a system that operates very reliably for each of these two very different types of material/ash and can be done with minimal conveyors and drag chains.

ProcessBarron has installed numerous Submerged Bottom Ash Collection Conveyor systems, and with the addition of the Submerged Shaftless Screws to handle the siftings ash, plants across the country are seeing improved efficiency and less downtime due to equipment malfunctions.  Contact ProcessBarron today at 888-663-2028 or visit us to learn more about ash handling equipment solutions.