Hydrogen production by decomposition of ethanol in the afterglow of atmospheric-pressure nitrogen microwave plasma torch

Abstract

Abstract The atmospheric-pressure microwave plasma torch (MPT) is employed to produce hydrogen via the decomposition of ethanol (C2H5OH). The ethanol aerosol is injected directly into the early afterglow of a nitrogen plasma and the products are analyzed with Fourier transformation infrared spectrometery and gas chromatography. Meanwhile, optical emission spectroscopy is used to diagnose the plasma. The influencing factors for the hydrogen production are investigated with respect to the location of the ethanol injection, the ethanol feed rate, the ethanol microdroplet size, the absorbed microwave power, the total flow rate of carrier gas, and the Ar–N2 mixture ratio, respectively. It is found that the excited species and high temperature play important roles in ethanol decomposition. In addition, the effect of the gas flow pattern in the reaction chamber on hydrogen production is analyzed with the aid of computational fluid dynamics and the mechanism of ethanol decomposition by MPT is discussed. Hydrogen production in our experiment was successful, with a production rate of up to 1309 l h−1, an energy yield of up to 468 l kWh−1, and a hydrogen yield of up to 95%, respectively.