Biomass Co-Firing In Power Plant
Organic wastes and residues have been the major biomass sources so far, but energy crops are gaining importance and market share. And in large scale power plant, biomass co-firing boilers are installed to provide the striving force steam.
What are biomass resources?
Biomass resources include agricultural residues; animal manure; wood wastes from forestry and industry; residues from food and paper industries; municipal green wastes; sewage sludge; dedicated energy crops such as short-rotation (3-15 years) coppice (eucalyptus, poplar, willow), grasses (Miscanthus), sugar crops (sugar cane, beet, sorghum), starch crops (corn, wheat) and oil crops (soy, sunflower, oilseed rape, iatropha, palm oil).
Biomass co-firing boiler in power plant
ZBG provides biomass and coal co-firing boilers in power station. Biomass co-firing in modern, large scale coal power plants is efficient, cost-effective and requires moderate additional investment. In general, combustion efficiency of biomass can be 10 percentage points lower than for coal at the same installation, but co-firing efficiency in large-scale coal plants (35%-45%) is higher than the efficiency of biomass-dedicated plants. In the case of cocombustion of up to 5%-10% of biomass (in energy terms) only minor changes in the handling equipment are needed and the boiler is not noticeably derated.
For biomass exceeding 10% or if biomass and coal are burned separately, then changes in mills, burners and dryers are needed. In addition, coal ashes that are used to produce construction materials should not be contaminated with tar and alkali metals-rich ash from biomass. Many co-firing technology options have been demonstrated in several countries (Northern Europe, United States and Australia) in some 150 installations using different feedstock (wood biomass, residues and crops). Using low-cost local biomass, the incremental investment may have a short payback period (2 years), but low-quality biomass such as herbaceous crops and wet wood may produce tar and cause slagging and fouling that affects plant reliability and raises costs.