Effects of a dehydrating agent on the carbonization of wood

The carbonization of sulfuric acid impregnated wood meal and wood block was studied by using thermogravimetry (TG) and scanning electron microscopy (SEM). The samples were carbonized up to 800 °C at a heating rate of 10 °C/min under nitrogen. Improvement of the char yield was observed to be similar to the case of cellulose. Without sulfuric acid impregnation, the wood blocks significantly shrank on carbonization, and the shrinkage was strongly anisotropic. The degree of shrinkage was in the order of tangential > radial > longitudinal directions. Sulfuric acid impregnated wood blocks largely retained the size and cell wall morphology. The nitrogen adsorption surface area of wood meal char prepared with sulfuric acid impregnation was greater than that of the control. Thus, the carbonization of wood with sulfuric acid impregnation was found to be advantageous in mass yield and preservation of size and shape.