A Kinetic Study of Xylan Solubility and Degradation during Corncob Steaming

A process using a dilute acid pre-treatment followed by a dry-steaming to extract xylan from corncobs was studied with an emphasis on examining the kinetic characteristics of dry-steaming products (xylan, reducing sugar and furfural) with selected kinetic models. Corncobs with particle size of < 4 · 75 mm were soaked in a 0·1% H₂SO₄ solution at 60 °C for 12 h before they were placed in an autoclave for a dry-steam processing at 125, 135, 145, and 155 °C. The yields of xylan, reducing sugar and furfural were fitted to a two-step first-order reaction model. The results suggested that the dilute acid pre-treatment followed by a dry-steaming process may have sensitised xylan to hydrolytic reactions and hence helped to lower the activation energy and increase the rate of xylan solubility. The yield of furfural during a 155 °C dry-steaming was 2·5-3·0 times higher than that at three other temperatures and hence was not recommended for use in xylan extraction.