Offsetting anthropogenic carbon emissions from biomass waste and mineralised carbon dioxide
Nimisha Tripathi, Colin D. Hills, R. S. Singh, Jamuna Sharan Singh
Abstract
Abstract The present work investigates biomass wastes and their ashes for re-use in combination with mineralised CO 2 in cement-bound construction products. A range of biomass residues (e.g., wood-derived, nut shells, fibres, and fruit peels) sourced in India, Africa and the UK were ashed and exposed to CO 2 gas. These CO 2 -reactive ashes could mineralise CO 2 gas and be used to cement ‘raw’ biomass in solid carbonated monolithic composites. The CO 2 sequestered in ashes (125–414 g CO 2 /kg) and that emitted after incineration (400–500 g CO 2 /kg) was within the same range (w/w). The CO 2 -reactive ashes embodied significant amounts of CO 2 (147–424 g equivalent CO 2 /kg ash). Selected ashes were combined with raw biomass and Portland Cement, CEM 1 and exposed to CO 2 . The use of CEM 1 in the carbonated products was offset by the CO 2 mineralised (i.e. samples were ‘carbon negative’, even when 10% w/w CEM 1 was used); furthermore, biomass ashes were a suitable substitute for CEM 1 up to 50% w/w. The approach is conceptually simple, scalable, and can be applicable to a wide range of biomass ashes in a closed ‘emission-capture’ process ‘loop’. An extrapolation of potential for CO 2 offset in Europe provides an estimate of CO 2 sequestration potential to 2030.