The Effect of Binders on the Behavior of Biocarbon Briquettes Under the Stresses of a Submerged Arc Furnace

Abstract

Abstract

Currently, the use of biocarbon in the iron and steel industry is quite limited due to biocarbon’s properties, namely its high gasification reactivity, low apparent density, and weak mechanical strength. In this work, the target is to tackle these issues by briquetting hydrolysis lignin biomass prior to pyrolysis. The idea behind this is to bring particles closer to each other so that during the charring stage of carbonization, the interaction between the particles would be improved, thus forming a solid carbon network throughout the briquette structure. Moreover, the briquettes were doped with bentonite, which was considered to act as a gasification reactivity inhibitor in the briquettes. Two organic binders, starch and glycerol, were used as references for the bentonite. The produced briquettes were tested by simulating the thermochemical and mechanical stresses of a submerged arc furnace. In gasification reactivity experiments at 1100 °C and in a 50/50 CO/CO2 gas atmosphere, the reaction rate of bentonite-containing briquettes was found to be up 23% lower (LIG1) than that of the briquettes without bentonite. However, the carbon conversion curve of the bentonite-containing briquettes suggests that there is no substantial change in the gasification mechanism, but the rate of the chemical reaction (adsorption–reaction–desorption) was decreased when a biocarbon briquette was doped with bentonite. Additionally, bentonite was found to have a negative impact on the strength properties of the briquettes. However, up to an 8% bentonite addition, the compression strength of the briquettes remained above 20 MPa, which is the level of industrial coke.