Investigation of ESEM/EDX to measure liquor penetration and diffusion in Eucalyptus grandis wood chips during kraft pulping

Abstract

Environmental scanning electron microscopy coupled with energy dispersive x-ray (ESEM/EDX) was optimised to measure the penetration and diffusion of cooking liquor into Eucalyptus grandis wood chips during kraft pulping. The moisture content of the cooked wood chips influenced the ESEM/EDX measurement of sodium and sulphur, whilst the contribution of sodium and sulphur already present in the wood prior to pulping was negligible. Using the optimised ESEM/EDX method, investigations into the use of pulping aids during kraft pulping showed that the penetration and diffusion of sodium and sulphur was enhanced by the use of anthraquinone (AQ) and a combination of AQ and surfactant. As expected, chip thickness was found to influence the penetration and diffusion of cooking liquor into the wood structure during cooking.