Prans Brazdausks

Influence of Biomass Pretreatment Process Time on Furfural Extraction from Birch Wood

Abstract Furfural is a biomass derived-chemical that can be used to replace petrochemicals. In this study, dilute sulphuric acid hydrolysis was used for hemicelluloses secession from birch wood. The reaction was investigated at different biomass treatment times (10-90 min, increasing it by 10 min). We found that the greatest amount of furfural 1.4-2.6%, which is 9.7-17.7% from theoretical possible yield, was formed in the first 30 min of the beginning of birch wood pentoses monosaccharide dehydration, but the greatest yield of furfural 10.3%, which is 70.0% from the theoretical yield, can be obtained after 90 min. Given that furfural yield generally does not exceed 50% from the theoretical amount, the result can be considered as very good.

Effect of the Acid Hydrolysis Temperature on the Conversion of Birch Wood Hemicelluloses into Furfural

In this study, a new dilute sulphuric acid hydrolysis method was used for hemicelluloses secession from birch wood. The furfural extraction was investigated at different process temperatures (132°C ‑ 162°C, increasing it by 5°C) and at constant amount of catalyst 3.0%, calculated on oven‑dried wood. The greatest amount of furfural 11.09%, which is 75.6% from the theoretical possible yield, was formed at temperature 147°C after 90 min from the beginning of the birch wood pentoses monosaccharides dehydration process.

Evaluation of Equilibrium Moisture Content and Chemical Composition in Torrefied Birch Wood

Birch wood veneer shorts from the plywood production plant in Latvia were fractionated to 0.63-2.00 mm and torrefied 30 min at 250, 260, 270, 280, 290 and 300 °C. The evaluation of hydrophobicity to untreated and torrefied birch wood was studied at constant climatic conditions (65±2% relative humidity, 22.8±0.3 °C) while standard chemical analysis methods were used to ascertain the structural and physical changes. Torrefaction process has a strong effect on the equilibrium moisture content of the fuel. The equilibrium moisture content of the torrefied wood decreased by 34% and more compared to the raw wood. Compositional analysis showed that the hemicelluloses are thermally more unstable than cellulose and lignin. During torrefaction process, hemicelluloses were almost removed, but extensive cellulose and light lignin degradation occurred only at torrefaction temperature of 300 °C. As the optimal torrefaction temperature can be considered 280 °C, where equilibrium moisture content of fuel was 5.9% and higher heating value 20.1 MJ/kg.