Title:
Experimental Investigation of Combustion Performance and Cofiring Characteristics of Torrefied Biomasses in a Pulverized Coal Furnace
Author(s):
Ndibe, C., Maier, J., Scheffknecht, G.
Document(s):
Paper
Slide presentation
Abstract:
Torrefaction of biomass involves heating biomass between 200°C to 320°C in the absence of O2 and thereby reducing its moisture and volatile content. In comparison to untreated biomass, torrefied biomasses are dryer, more hydrophobic, brittle, more energy dense and have higher char contents. Prospects for logistics, handling, storage and milling are improved while cofiring of torrefied biomasses with coal at higher thermal shares in conventional coal boilers is potentially more feasible. The study investigated the cofiring of torrefied biomasses at 50% thermal shares as well as 100% monocombustion cases. Experiments were carried out at IFK’s 20kW, electrically heated, drop tube reactor with a range of torrefied ligno-cellulosic biomasses (including spruce, pine, and forest residue), non-thermally treated wood, bituminous coal and lignite. The reactor was maintained at 1200oC for the experiments while the overall stoichiometric ratio was kept constant at 1.15. During the combustion tests, char and flue gas samples were extracted at various distances along the vertical axis of the down-fired reactor while measurements were performed to evaluate combustion reactivity, emissions and burn-out. The comparative study demonstrates the feasibility of cofiring at higher thermal shares (50%) while also showing avenues for managing emissions by fuel mixing and air-staging.
Keywords:
biomass, co-combustion, combustion, torrefaction, cofiring
Topic:
Biomass Conversion Technologies for Heating, Cooling and Electricity
Subtopic:
Solid biofuels combustion in large utilities
Event:
22nd European Biomass Conference and Exhibition
Session:
2AO.7.3
Pages:
409 - 417
ISBN:
978-88-89407-52-3
Paper DOI:
10.5071/22ndEUBCE2014-2AO.7.3
Price:
FREE
