Evaluation of techno-economic performance for decarbonized hydrogen and power generation based on glycerol thermo-chemical looping cycles

Abstract

Glycerol represents a valuable side product from biodiesel production. This work evaluates glycerol valorization in view of energy-efficient hydrogen & power generation using chemical and calcium looping thermo-chemical cycles. Two looping options were evaluated: glycerol steam reforming followed by a syngas-based looping cycle and direct glycerol conversion in a looping cycle. The evaluated H2 systems based on glycerol conversion via ilmenite and calcium looping cycles generate 100,000 Nm3/h high purity hydrogen coupled with a plant decarbonization rate up to 98%. Timely adjustable co-production of H2 and electricity was also evaluated as limited (0 to 200 MW hydrogen thermal output) and fully flexible designs. As benchmark cases, a glycerol reforming design without CO2 capture and one decarbonized design by with pre-combustion chemical absorption using MDEA were considered. As the techno-economic investigations reveal, the overall energy efficiencies of thermo-chemical looping designs are superior to decarbonized glycerol reforming concept based on gas-liquid absorption by 5.3 to 11.7 net points as well as the decarbonization rates 93–98% vs. 71%. Flexible co-production systems show improved performance: higher efficiency (3.4 net points), reduced investment cost (9%) and electricity cost (11%) per 100 MW thermal hydrogen output.