## 1 Introduction
Their experimental findings showed that, while the density of different formed species in the plasma discharge medium of the reactor increased, a stable performance of the reactor for long time applications was guaranteed. Moreover, at higher methane supply rates, while the density of hydrogen molecules was decreased, the flow rate of formed hydrogen was higher. On the other hand, there is lack in the investigations of the conversion of LPG to hydrogen using the electric discharge technique in the literatures. The electric discharge technique is expected to be an efficient technique for conversion of LPG to other alternative fuel gases such as hydrogen and study of the electric and spectroscopic characteristics of the electric discharge in LPG is one of the important keys to understanding the conversion mechanisms and achieve efficient reforming of LPG. [PERSON] et al. [13] investigated the electric discharge in LPG using DC high voltage (0.4-3 kV) at gas pressure in the range of 1 to 25 torr and the electric and spectroscopic characteristics of the discharge were studied at different discharge conditions. Deviations from [PERSON]'s law were observed as a result of the change of the distance between the two electrodes. Two discharge modes, namely, glow and spark discharges, were observed in the discharge current waveforms. The discharge current waveforms indicated a repetitive pulsed behavior with frequencies of 5 kHz to 5 MHz depending upon the applied voltage and the gas pressure. The emitted spectra from the discharge were also studied near both the cathode and anode using different electrode materials. The H\({}_{\alpha}\) line and C\({}_{2}\) Swan band system were observed, which confirmed the conversion of LPG to hydrogen and carbon clusters. In 2018, [PERSON] et al. [14] introduced a DC reactor with rotating electrode for hydrogen production from methane decomposition and the effect of the electrode rotational frequency over the methane decomposition was studied. One of the main conclusions was that the methane conversion and energy efficiency with the rotating electrodes was improved in comparison to the fixed electrode, because the produced plasma was stabilized in this configuration. In this work, a new rotating electrode plasma reactor is introduced for hydrogen production from LPG gases. The developed plasma reactor works at atmospheric pressure, room temperature, and a relatively low operating power. Hence, it has a stable performance without electrical shocks. Electrical characterization of the plasma produced in this reactor is performed to determine the plasma mode. Then, the hydrogen production, conversions of the C\({}_{4}\)H\({}_{10}\) and C\({}_{3}\)H\({}_{8}\) gases and the energy efficiency of the conversion in the developed reactor are studied by GC. Moreover, preliminary characterization of this plasma is made using the OES technique and the main objective is to study the applicability of this reactor in hydrogen production with low CO\({}_{\rm x}\) formation, by analyzing the emission spectrum and species formed inside the plasma. The dependence of the spectrum on the applied high voltage, electrode rotation frequency, and flow rate is also studied. The main plasma parameters of discharge produced in this reactor, such as the gas temperature, the electron density and temperature are determined as these parameters have an important influence on the capacity of plasma for the dissociation of the C\({}_{4}\)H\({}_{10}\) and C\({}_{3}\)H\({}_{8}\) molecules of the mixture.