Biochar-pellets as substitute for fossil coal in metallurgical processes

Abstract

This thesis serves as a base for later research on substituting fossil coal and coke with biochar in the Norwegian metallurgical industry. Because Norwegian electricity production is almost entirely based on carbon dioxide - neutral hydropower, the nation’s main pollutant is fossil coal. Biochar serves as an alternative to coal but can currently only partially satisfy the quality requirements for use in top-loaded smelting facilities. With comparison to fossil coal, biochar has a higher price and a lower mechanical strength. A coupling of pyrolysis and pelletising is therefore investigated to obtain a sustainable product with improved characteristics and without compromising the other requirements. Different compositions of feedstock for pelletising were investigated in a single pellet press. Good results were achieved with two binding agents, lignin and oil from a flash pyrolysis process. The materials were waste products from other processes to increase economic feasibility. Problems were discovered with the sticky characteristics of both materials during the process. Water was then applied as a lubricant to improve homogenising and extraction. Further experiments with more replicates and statistical analyses should be done to broaden the observations and extend the scientific value.