Synthesis Gas From Ethanol Using Low-Temperature Plasma Induced By Dielectric Barrier Discharge

Ethanol is one of the main products of high-quality utilization from biomass resources.Meanwhile,ethanol can be pyrolyzed to the syngas mainly containing hydrogen and carbon monoxide,which is generally produced both liquid or gaseous fuels as well as fuel cells.Low temperature plasma(LTP)has been demonstrated as one of the promising technologies in the fields of pollutant treatment and clean energy production,due to the unique advantages of low energy consumption,rapid response and strong maneuverability.Compared with the traditional high temperature catalytic cracking of ethanol,LTP can activate ethanol to produce syngas at room temperature and normal pressure.Therefore,this thesis explores the main effects and optimization methods of preparing syngas from activated ethanol by dielectric barrier discharge(DBD).The main contents and conclusions are as follows:Firstly,the effects of applied voltage and gas flow rate on the electrical characteristics were previously investigated in the self-made DBD reactor.The results show that the discharge mode belongs to a kind of typical filament discharge,and the electrical characteristics including discharge intensity,equivalent capacitance and discharge power are increased with the increase of applied voltage or the decrease of gas flow rate.Then,a series of single-factor experiments were carried out for exploring the effects of applied voltage,carrier gas flow rate,discharge frequency,water bath temperature and water-alcohol molar ratio on the preparation of syngas from activated ethanol by LTP.The experimental results show that under the conditions of applied voltage of 60 V,carrier gas flow of 30 ml/min,water bath temperature of 52℃,discharge frequency of 6.7 kHz and water-alcohol molar ratio of 4,the highest ethanol conversion rate is 54.36%,and the highest yields of hydrogen and carbon monoxide are 33.01%and 17.84%,respectively.Further,based on the experimental results of three factors and five levels,an optimization model is obtained by response surface methodology for analyzing the interaction among different operational conditions.The suitable operational condition was verified by experimental cases.The results show that the water-alcohol molar ratio has the most significant effect on ethanol conversion,hydrogen yield and carbon monoxide selectivity.The applied voltage is most important for carbon monoxide yield and hydrogen selectivity.The predicted suitable operational conditions are as follows:the applied voltage is 58 V,the flow rate of carrier gas is 35.91 ml/min,the ratio of water to alcohol is 4.86,and the corresponding response values are ethanol conversion of 62.39%,hydrogen yield of 36.18%,hydrogen selectivity of 57.34%,carbon monoxide yield of 13.10%,and carbon monoxide selectivity of 20.63%.The differences between predicted value and experimental value are in the range of ±5%.