Objective In order to suppress carbon deposition, optimize operating conditions and increase the efficiency of hydrogen production, based on the concept of green hydrogen production and on-site hydrogen production, a new hydrogen production technology by plasma reforming is researched, and a set of equipment for ethanol reforming using rerotating arc plasmas had been optimized.
Methods Air is used as the working gas to investigate the effects of oxygen to ethanol molar ratio (n(O2)/n(Et)), ethanol flow rate, discharge voltage and discharge distance on the reforming results.
Results Too large or too small n(O2)/n(Et) is not conducive to reforming. When the n(O2)/n(Et) is 0.9, the ethanol conversion rate can reach 100%, and the hydrogen selectivity is 41.21%. When the n(O2)/n(Et) is 1.2, the hydrogen yield and hydrogen selectivity achieve maximum values of 1 200.26 L/h and 50.01%, respectively. Properly increasing the ethanol flow rate can increase the ethanol conversion rate and energy efficiency, but will reduce the hydrogen selectivity and hydrogen yield. The discharge voltage has an obvious positive effect on the reforming effect. When the discharge voltage is 1.8 kV, the maximum energy yield of hydrogen is 687.94 L/kW·h. Properly increasing the discharge distance can improve the reforming effect, but it should not be too large, otherwise the arc will be unstable.
Conclusions This set of reforming equipment has shown a good effect in suppressing the formation of deposited carbon and the efficiency of hydrogen production. The best experimental conditions are the n(O2)/n(Et) of 1.1, the ethanol flow rate of 33.7 mL/min, the discharge voltage of 1.8 kV, and the discharge distance of 2.5 mm. The gas phase products of reforming are H2, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H6, and C3H8. Among them, the content of C2 or higher hydrocarbons is lower.
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