Biomass Combustion for Energy Saving

Combustion equipment for solid biomass: grate types, suitable fuels and a reference project.

Biomass Energy

What is biomass energy?

Biomass energy comes from organic matter such as energy crops and agricultural residues, converted by thermal, chemical or biological processes. It is a renewable energy source.

Solid: refuse, refuse-derived fuel (RDF), agricultural residues, wood
Liquid: bio-oil, biodiesel, bioethanol
Gaseous: syngas, biogas

Based on TMM's technical presentation of June 2016 by General Manager Cheng Ming Chen.

Combustion equipment for solid biomass

Type	Grates
Fixed grate	Fixed Grate, Dumping Grate, Reciprocating Grate
Moving grate	Chain Grate, Traveling Grate
Fluidized bed	BFB (bubbling), CFB (circulating)

Fuel type and particle size determine the grate. Compare fuel costs with the fuel cost calculator.

CO₂ Comparison

CO₂ generation by fuel

Calculated for a boiler producing 25,000 kg/h of steam. Wood has high moisture (34%) and a low heating value, so more fuel is needed for the same steam output.

CO2 generation by fuel
Item	Coal	No. 6 fuel oil	No. 2 fuel oil	Natural gas	Wood
Composition	C 59.00%, H 3.00%, N 1.60%, S 1.00%, O 5.50%, H₂O 14.20%, ash 15.70%	C 86.81%, H 12.19%, N 0.15%, S 0.48%, O 0.20%, H₂O 0.15%, ash 0.007%	C 87.00%, H 12.50%, N 0.10%, S 0.10%, O 0.20%, H₂O 0.10%, ash 0%	N₂ 0.04%, CH₄ 88.75%, C₂H₆ 6.23%, C₃H₈ 3.53%, C₄H₁₀ 1.39%, C₅H₁₂ 0.06% (vol%)	C 32.34%, H 3.96%, N 0.26%, S 0%, O 29.04%, H₂O 34.00%, ash 0.40%
Lower heating value	5,369 kcal/kg	9,750 kcal/kg	9,845 kcal/kg	9,804 kcal/Nm³	2,315 kcal/kg
CO₂ generated	2.1619 kg/kg	3.1809 kg/kg	3.1879 kg/kg	2.3117 kg/Nm³	1.1850 kg/kg
Fuel consumption25,000 kg/h boiler	3,007.6 kg/h	1,656.2 kg/h	1,640.2 kg/h	1,647 Nm³/h	6,975.3 kg/h
CO₂ quantity	6,502.1 kg/h	5,268.2 kg/h	5,228.7 kg/h	3,807.4 kg/h	8,265.7 kg/h
Ratio (No. 6 oil = 1)	1.2342	1.0000	0.9925	0.7227	1.5690