Effect of Superficial Velocity on Tar from Downdraft Gasification of Biomass

Abstract

Changes in the amount and composition of tar according to superficial velocity (SV) were investigated in a downdraft biomass gasifier. SV of the downdraft gasification with air was varied in the range of 0.3-0.7 m/s, and tar was recovered at the gasifier outlet. The tar was classified as gravimetric tar and gas-chromatography-detectable (GC-detectable) tar. The lowest gravimetric tar yield (0.7%) was obtained at 0.4 m/s SV, and the highest was obtained at 0.7 m/s. GC-detectable tar yield was highest (1.5%) at 0.7 m/s. One-ring aromatics and naphthalene accounted for more than 80% of GC-detectable tar mass. Some constituents of GC-detectable tar showed specific trends according to SV, although the main composition did not show extreme change. The effect of SV on the production of gases and particles was also studied.

Thermochemical Biomass Gasification: A Review of the Current Status of the Technology

“…ER is the ratio of air flow to the airflow required for stoichiometric combustion of the biomass, which indicates extent of partial combustion. The SV is the ratio of air flow to the cross-sectional area of the gasifier which removes the influence of gasifier dimension by normalization [30]. Hence, both ER and SV are directly proportional to the airflow.…”

Production of Activated Char and Producer Gas Sewage Sludge

“…Tar sampling and analysis were used by the method of biomass technology groups (BTGs) (Good et al, 2005;Neeft, 2005;Phuohuakrat et al, 2010;Son et al, 2009;Yamazaki et al, 2005). Wet sampling module was installed with 6 impingers (250 mL) in two separated isothermal baths for adsorption of tar and particles.…”

Operating and Performance Gasification Process Parameters

“…It represents the ratio between the amount of air/oxygen carried in the gasification agent (oxidant) and theoretical amount of air/oxygen required for complete combustion of the feedstock (biomass) according to stoichiometry (Gabra, et . ER is a measure of the extent of partial combustion (Yamazaki, et al, 2005). Operationally, ER is an important parameter as according to it composition of the synthetic (syn) gas produced and chemical energy may vary.…”

“…SV is, once more, a ratio that relates air/oxygen flow rate to the cross sectional area of the gasifier (Yamazaki, et al, 2005).…”