Syngas/H2 production from bioethanol in a continuous chemical-looping reforming prototype

• Use of bioethanol in chemical-looping reforming produces H2 with low CO2 emissions.
• 50 h of continuous operation in a 1 kWth CLR unit with Ni-based oxygen carriers
• Rich syngas (61% H2, 32% CO) was reached at auto-thermal conditions.
• Syngas composition was close to thermodynamic equilibrium.
• High purity H2 and pure N2 could be obtained in the global process.

Chemical-looping reforming (CLR) allows H2 production without CO2 emissions into the atmosphere. The use of a renewable fuel, bioethanol, in an auto-thermal CLR process has the advantage to produce H2 with negative CO2 emissions. This work presents the experimental results obtained in a continuously operating CLR unit (1 kWth) using ethanol as fuel. Two NiO-based oxygen carriers were used during more than 50 h of operation. The influence of variables such as temperature, water-to-fuel and oxygen-to-fuel molar ratios was analysed. Full conversion of ethanol was accomplished and carbon formation was easily avoided. A syngas composed of ≈ 61 vol.% H2, ≈ 32 vol.% CO, ≈ 5 vol.% CO2 and ≈ 2 vol.% CH4 was reached at auto-thermal conditions for both materials. Gas composition was closed to the given by the thermodynamic equilibrium. These results demonstrate the technical viability of H2/syngas production by using bioethanol in an auto-thermal CLR process.

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