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

Abstract

Abstract:Chemical-looping reforming (CLR) allows H 2 production without CO 2 emissions into the atmosphere. The use of a renewable fuel, bioethanol, in an auto-thermal CLR process has the advantage to produce H 2 with negative CO 2 emissions. This work presents the experimental results obtained in a continuously operating CLR unit (1 kW th ) using ethanol as fuel. Two NiO-based oxygen carriers were used during more than 50 hours of operation. The influence of variables such as temperature, water-to-fuel 2 and oxygen-to-fuel molar ratios was analysed. Full conversion of ethanol was accomplished and carbon formation was easily avoided. A syngas composed by ≈61 vol.% H 2 , ≈32 vol.% CO, ≈5 vol.% CO 2 and ≈2 vol.% CH 4 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 H 2 /syngas production by using bioethanol in an auto-thermal CLR process.

Optimization of hydrogen production with CO2 capture by autothermal chemical-looping reforming using different bioethanol purities

“…In a previous work [16] it was determined that the syngas composition obtained was very close to the defined by the thermodynamic equilibrium.…”

“…However, liquid fuels are becoming more relevant in the hydrogen production process in CLR processes. García-Labiano et al [16] evaluated the use of ethanol and Dou, Chen et al [17] the use of glycerol as fuel in CLR processes.…”

Autothermal chemical looping reforming process of different fossil liquid fuels

“…To check the validity of the above assumptions, new experiments at low temperatures (600e850 C) were carried out in a CLR prototype, ICB-CSIC-liq1, using diesel and ethanol as fuels. More information about the prototype design and operation can be found elsewhere [17]. A Ni-based material, NiO18eaAl 2 O 3 [11,17] was used as oxygen carrier for the tests.…”

“…Another specific advantage of the a-CLR process is the possibility of obtaining pure N 2 at the outlet stream of the AR by controlling the amount of air fed into the AR [17].…”

“…Although the main experience of obtaining H 2 by the CLR process is with gaseous fuels [8,18], liquid fuels are becoming more relevant in the last years, being evaluated ethanol [17,19], glycerol [20], free sulphur kerosene [21], and biomass pyrolysis oils [22].…”