Biogas upgrading by chemical absorption using ammonia rich absorbents derived from wastewater.

摘要: The use of ammonia (NH3) rich wastewaters as an ecological chemical absorption solvent for the selective extraction carbon dioxide (CO2) during biogas upgrading to 'biomethane' has been studied. Aqueous absorbents up 10,000 gNH3 m(-3) demonstrated CO2 rates higher than recorded in literature packed columns using 20,000-80,000 g NH3 which can be ascribed process intensification provided by hollow fibre membrane contactor used this study support absorption. Centrifuge return liquors (2325 ionised ammonium, NH4(+)) and a regenerant (477 gNH4(+) m(-3)) produced from cationic ion exchanger harvest NH4(+) crude wastewater were also tested. Carbon fluxes measured both compared reasonably with analogue solvents equivalent concentration. Importantly, demonstrates that facilitate chemically enhanced separation eliminates need costly exogenic chemicals or complex handling are critical barriers implementation When testing analogues, potential recover reaction product ammonium bicarbonate (NH4HCO3) crystalline form was illustrated. This is significant it suggests new pathway avoids biological nitrification produces stabilised into commercially viable fertiliser (NH4HCO3). However, real wastewaters, sodium calcium carbonate preferentially formed over NH4HCO3 although proposed manipulating exchange absorbent chemistry.