Waste-to-energy and biomass
Grate-fired boiler and mass-burn incinerator
Also known as grate-fired boiler, moving-grate incinerator, mass-burn incinerator.
A grate-fired boiler (also moving-grate incinerator or mass-burn incinerator) burns mixed municipal solid waste on a slowly moving grate without significant fuel pre-processing. As waste advances along the grate, it dries, ignites, burns out, and finally discharges as bottom ash. Mass-burn is the dominant design for municipal WtE plants worldwide.
Why mass-burn dominates municipal duty
- Tolerates unprocessed mixed waste
- Simple fuel handling — no shredding or pelletising needed
- Mature, robust, well-supported supply chain
- Established regulatory acceptance under IED and equivalent
- Scales from 50 t/day local plants to 3,000+ t/day urban facilities
Where fluidised-bed designs compete
CFB and BFB designs compete with mass-burn for specific duties — pre-sorted RDF/SRF, sewage sludge co-firing, biomass-only plants. Fluidised beds need more fuel preparation but offer lower NOx and better fuel flexibility.
Cleaning
Grate-fired WtE boilers benefit from sonic horns on the convective pass, ESP/baghouse hoppers and SCR. The fluidised-bed alternatives add cyclone-cleaning duty to the same list.
Related terms
Related terms
- Waste-to-energyWtE plants burn municipal solid waste, RDF, SRF and biomass to generate steam and electricity. Sticky chloride-rich ash defeats conventional cleaning; sonic horns are the dominant fit.
- Municipal solid wasteMSW is mixed household and commercial waste — the primary fuel for mass-burn WtE plants. Variable composition produces variable fouling and ash chemistry.
- Bubbling fluidised-bed boilerA BFB boiler suspends fuel in a slowly-bubbling bed of inert solids. Lower fluidisation velocity than CFB; suited to high-moisture biomass and sludges.
- Circulating fluidised-bed boilerA CFB boiler burns fuel in a turbulent bed of sand, ash and limestone circulated by an upward-flowing gas stream. Tolerates coal, biomass, RDF and lignite; produces low NOx.