Determination of mass loss for steam exploded wheat straw

Steam Explosion is often used to improve biogas yields of lignocellulosic biomass. To evaluate the effects of steam explosion pretreatment on biomass composition and biogas yields mass loss has to be taken into account. For the upscaling from lab to industrial scale and economic assessments calculation of mass loss is essential to avoid overestimation of biogas yields. Different approaches to estimate mass loss were compared in this study: Mass balances did not account for biomass getting stuck on the inner walls of the steam explosion apparatus and due to underestimation of dry matter content overestimated mass loss. Ratios of ash and lignin concentrations were inaccurate or overestimated mass loss, however loss of pentosans allowed estimation of maximum mass loss for pretreatment temperatures below 200°C. For temperatures below 200°C ratio of glucan concentrations was found to be the best method to calculate mass loss.