Techno-economic appraisal of waste cellulose processing

Huge quantities of waste cellulose fibres are being produced in textile, food and particularly paper industries. Their incineration without a costly external increase of the combustion temperature raises environmental concerns because hazardous substances may be formed due to the fact that commercially produced biomass is routinely exposed to excessive amounts of agrochemicals. Fermentation techniques are also unfavourable as the naturally low biodegradability of cellulose requires energy-intensive pretreatment, long hydraulic retention times and heating of huge volumes or costly catalysts. A technical-economic assessment was carried out in a newly developed pyrolysis apparatus that prevents production of tar and flue gases and produces exclusively solid pyrolysis residues. It was confirmed that such a solution could be economically and environmentally beneficial.