title: Measuring the concentration of carboxylic acid groups in torrefied spruce wood.
abstract: Torrefaction is moderate thermal treatment (∼200-300°C) to improve the energy density, handling and storage properties of biomass fuels. In biomass, carboxylic sites are partially responsible for its hygroscopic. These sites are degraded to varying extents during torrefaction. In this paper, we apply methylene blue sorption and potentiometric titration to measure the concentration of carboxylic acid groups in spruce wood torrefied for 30min at temperatures between 180 and 300°C. The results from both methods were applicable and the values agreed well. A decrease in the equilibrium moisture content at different humidity was also measured for the torrefied wood samples, which is in good agreement with the decrease in carboxylic acid sites. Thus both methods offer a means of directly measuring the decomposition of carboxylic groups in biomass during torrefaction as a valuable parameter in evaluating the extent of torrefaction which provides new information to the chemical changes occurring during torrefaction.
authors.affiliation: Åbo Akademi University, Process Chemistry Center, Piispankatu 8, FI-20500 Turku, Finland. khazrai@abo.fi
authors.forename: Tooran
authors.initials: T
authors.lastname: Khazraie Shoulaifar
authors.forename: Nikolai
authors.initials: N
authors.lastname: Demartini
authors.forename: Ari
authors.initials: A
authors.lastname: Ivaska
authors.forename: Pedro
authors.initials: P
authors.lastname: Fardim
authors.forename: Mikko
authors.initials: M
authors.lastname: Hupa
mesh_terms: D000143:Acids / Q000737:chemistry; D000327:Adsorption; D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D002264:Carboxylic Acids / Q000032:analysis*; D006813:Humidity; D007287:Inorganic Chemicals / Q000032:analysis; D008751:Methylene Blue / Q000737:chemistry; D028222:Picea / Q000737:chemistry*; D011199:Potentiometry; D013696:Temperature; D013997:Time Factors; D014934:Wood / Q000737:chemistry*
chemical_list: D000143:Acids; D002264:Carboxylic Acids; D007287:Inorganic Chemicals; D008751:Methylene Blue