Hydrogen Generation From Methanol Decomposition With Corona Discharge And Its Modeling Study

Methanol is generally considered as a store of hydrogen with safety, cheapness and flexility. It is made from various resources in addition to petroleum. It is becoming an important material for generation of hydrogen on a medium or mini scale, taking an essential role for application of fuel battery. Plasma method for generating hydrogen from methanol needs no catalysts, allowing the reactions occurred at a low temperature with a small space within much shorter time. This method will be a good choice of hydrogen production at a variable condition. In this work the characteristic of methanol decomposition to hydrogen using corona discharge was investigated. The chain reactions in the plasma were modeled. The fundamental issues on design of hydrogen generation using corona discharge were investigated systematically.An experimental investigation was conducted to study the effects of residence time and concentration of feed on H₂. yield and H₂. generation rate with positive corona. The comparison of negative corona and AC corona at the waveform of sinusoid was made. The results suggested that high concentration of feed gave high H₂. generation rate and power efficiency, while the highest H₂. generation rate was achieved at the residence time of ca. 0.03 s. It was found that H₂. yield was increased with the increasing specific energy density, which affected by the residence time, concentration of feed, electrical power, etc. The effect of electrode gap was experimentally investigated. The larger gap was considered as an efficient way for hydrogen generation, as power and residence time were increased in the case of given feed concentration. The effect of waveform and frequency of AC power were experimentally found notable. Relative to current abroad reports, the reactor used in the research had a notable advantage at energy efficiency and productivityIt was found that the ethylene glycol was produced in addition to H₂. and CO. It has been considered that ethylene glycol was synthesized through methanol coupling.Based on the analysis and discussion of the experimental results, kinetic models were built on the principal and secondary reactions of methanol decomposition occurred in plasma using Matlab6.0. By analyzing of the reaction mechanism, three radical initial states were speculated in the plasma decomposition of methanol, founded on the enthalpies of the nine radicals from the decomposition. 115 reactions involving 27 species were selected for kinetic analysis. The calculated results werebasically consistent with the experimental results. The relationship between the layer of reactive boundary and type of power was estimated.According to the calculation results, to get a better yield of ethylene glycol from methanol using plasmas, voltage drop and AC corona with the waveform of sinusoid are more suitable.Based on the result of experimental and kinetic analyses a fountain mode was suggested, in which the relationship between energy of electron and reactive mechanism in plasma was established in the term of possibility of radical reaction occurred in the plasma. The fountain mode may serve as the theory for practical application of plasma technology.