Combustion and fuel characterisation of wheat distillers dried grain with solubles (DDGS) and possible combustion applications

• Published in: Fuel (Guildford) 2012-12, Vol.102, p.208-220
• Main Authors: Eriksson, Gunnar, Grimm, Alejandro, Skoglund, Nils, Boström, Dan, Öhman, Marcus
• Format: Article
• Language: English
• Subjects: Agglomeration; Alkali; Annan kemiteknik; Applied sciences; Ash transformations; Biofuel; Biomass; Chemical Process Engineering; Combustion; Energiteknik; Energy; Energy Engineering; Energy. Thermal use of fuels; Ethyl alcohol; Exact sciences and technology; Fuels; Kemiska processer; Natural energy; Other Chemical Engineering; Phosphorus; Slagging; Straw; Wheat
• ISSN: 0016-2361; 1873-7153; 1873-7153
• DOI: 10.1016/j.fuel.2012.05.019

► Fuel properties of residues from wheat-based ethanol production were determined. ► Fluidized bed, grate and powder combustion, and ash characterisation. ► Powder combustion produced K- and P-rich fine particles, with risks of fouling. ► The slagging and bed agglomeration tendencies were high. ► Mixtures with Ca-rich logging residues reduced these tendencies considerably. The present transition to a sustainable global energy system requires that biomass is increasingly combusted for heat and power production. Agricultural fuels considered include alkali-rich fuels with high phosphorus content. One such fuel is wheat distiller’s dried grain with solubles (wheat DDGS) from wheat-based ethanol production. Further increases in ethanol production may saturate the current market for wheat DDGS as livestock feed, and fuel uses are therefore considered. Fuel properties of wheat DDGS have been determined. The ash content (5.4±1.6%wtd.s.) is similar to many agricultural fuels. In comparison to most other biomass fuels the sulphur content is high (0.538±0.232%wtd.s.), and so are the contents of nitrogen (5.1±0.6%wtd.s.), phosphorus (0.960.±0.073%wtd.s.) and potassium (1.30±0.35%wtd.s.). To determine fuel-specific combustion properties, wheat DDGS and mixes between wheat DDGS and logging residues (LR 60%wtd.s. and DDGS 40%wtd.s.), and wheat straw (wheat straw 50%wtd.s., DDGS 50%wtd.s.) were pelletized and combusted in a bubbling fluidised bed combustor (5kW) and in a pellets burner combustor (20kW). Pure wheat DDGS powder was also combusted in a powder burner (150kW). Wheat DDGS had a high bed agglomeration and slagging tendency compared to other biomass fuels, although these tendencies were significantly lower for the mixture with the Ca-rich LR, probably reflecting the higher first melting temperatures of K–Ca/Mg-phosphates compared to K-phosphates. Combustion and co-combustion of wheat DDGS resulted in relatively large emissions of fine particles (