Study of CO₂ gasification reactivity of biocarbon produced at different conditions

Biocarbon has a great potential to replace fossil reductants and help reduce greenhouse gas emissions from carbon intensive metallurgical industries. In this work, biocarbon samples were produced from Norway spruce under different final temperatures (550, 650 and 800 °C) and holding times (10 and 30 minutes). The CO₂ gasification reactivity of the biocarbon, or biomass char, samples was investigated in a thermogravimetric analyser at different gasification temperatures (850, 900 and 950 °C). The results show that the gasification reactivity of the spruce wood char produced at higher carbonization temperature is lower than of those produced at lower temperatures. The time of half conversion (t50) of spruce wood char produced at 800 °C was 334 seconds, while only 290 seconds was needed for that produced at 550 °C. In addition, the CO₂ gasification reactivity of spruce wood char produced at longer holding time (i.e., 30 minutes) is also lower than those prepared at shorter holding time (i.e., 10 minutes). All the spruce wood char samples showed significantly higher reactivity as they were gasified at a higher temperature. The time needed for half conversion of the tested char samples at a gasification temperature of 950 °C was only one fourth of those at a gasification temperature of 850 °C.