Bio-methane upgrading of pyrolysis gas from charcoal production

This article presents a novel route for bio-methane synthesis utilizing pyrolysis gas from charcoal production. It is a retrofit option that adds valuable bio-methane, which is efficiently produced when integrated with the charcoal production process. The pyrolysis gas from charcoal production can be used for bio-methane production instead of burning, while the required heat for the charcoal production is supplied by additional biomass. The aim is to evaluate the energy efficiency of bio-methane upgrading from two types of charcoal plants, with and without recovery of liquid by-products (bio-oil). Aspen simulations and calculations of the energy and mass balances are used to analyse the system. The yield of bio-methane compared to the import of additional biomass is estimated to be 81% and 85% (biomass to bio-methane yield) for the syngas case and the pyrolysis vapour case, respectively. When the biomass necessary to produce the needed electricity (assuming ηel = 33%) is included, the yields amount to 65% and 73%. The results show that the suggested process is a competitive production route for methane from lignocellulosic biomass.