What Is the Applicable Fuel Particle Size for Biomass Reciprocating Grates?
The fuel particle size for a biomass reciprocating grate is set separately for moulded fuel and loose biomass. The aim of size control is to keep the fuel bed permeable and prevent fines from blowing through or large pieces from jamming the grate.
Moulded fuel
Under GB/T 44906-2024, biomass moulded fuel for a reciprocating grate should be no longer than 100mm, with fines (no larger than 3mm) making up no more than 10%.
Loose biomass
Hard biomass (wood chips, branches) should preferably be no longer than 200mm, with the share no larger than 100mm above 80%; soft biomass (straw) should preferably be no longer than 400mm, with the share no larger than 200mm above 80%. Powder below 3mm should not exceed 10% overall, to avoid flame blow-through, air leakage and rapid burning of the grate.
| Fuel type | Length requirement | Fines control |
|---|---|---|
| Moulded fuel | No longer than 100mm | Share of particles no larger than 3mm at most 10% |
| Hard loose biomass (wood chips, branches) | Preferably no longer than 200mm, with over 80% no larger than 100mm | Powder below 3mm not more than 10% |
| Soft loose biomass (straw) | Preferably no longer than 400mm, with over 80% no larger than 200mm | Powder below 3mm not more than 10% |
Operating reference
Ordinary wood chips and crushed material commonly use 10-50mm, balancing permeability, burnout and grate life. All-fines fuel, oversized whole long straw and impurities containing many hard stones are not suitable for direct feeding.
