Preparation of Formed Coke from Biomass by Sequence of Torrefaction, Binderless Hot Briquetting and Carbonization

This paper proposes a method of preparing high-strength formed coke from woody biomass without binder. Chipped and pre-dried Japanese cedar was heat-treated in an inert atmosphere (i.e., torrefied) at 225–325°C (Tt), pulverized to sizes three different ranges, molded into briquettes (in the form thick disk with diameter/thickness ≈ 2.5) temperature up 200°C by applying mechanical pressure 128 MPa. The torrefied/briquetted (TBC) then converted heating 1000°C normal pressure. process sequence enabled prepare having indirect tensile strength (St) 8–32 MPa, which much higher than that torrefaction, below 5 torrefaction greatly improved pulverizability cedar, further promoted increasing Tt. St TBC both increased as particle decreased, but this explained only minor part significant effect Tt on coke. maximized = 275°C regardless degree pulverization. effects physicochemical properties were investigated detail. difference mainly due increment along carbonization 500–1000°C. Fracture surfaces had particular morphologies been inherited original honeycomb structure cedar.