Exergy efficiency and energy analysis of silicon production using coffee husks as a carbon material

Abstract

Abstract We used coffee husks as an additive during the smelting of industrial silicon. The influence of different carbon material mixtures on the efficiency of a silicon furnace was evaluated using the cover fires index, excess carbon index, and exergy efficiency index. The results showed that after adding coffee husks, the number of cover fires(Gh) was stable, the average number of cover fires time(Tg) ranged from 6 to 11 min, and the average interval of the cover fires(TG) increased. When semi-coke was used without coffee husks, the excess carbon index was 1.29, the non-recovery exergy efficiency was 0.342, and the recovery exergy efficiency was 0.435. After adding coffee husks, the excess carbon index decreased to 1.28, and the exergy efficiency increased to 0.343 and 0.437. When coffee husks were used without semi-coke, the excess carbon index was 1.25, the non-recovery exergy efficiency was 0.348, and the recovery exergy efficiency was 0.441. The results indicate that using coffee husks as a reducing agent stabilizes the furnace conditions, reduces carbon emissions, protects the environment, and improves the exergy efficiency of the silicon furnace. This study provides new insights into using biomass raw materials as reducing agents for silicon smelting.