Gong Wei-min

Coupling of methane under pulse corona plasma (I)

At normal temperature and pressure, pulse corona plasma was used as a new method for the dehydrogenative coupling of methane in the absence of oxygen. The effects of voltage polarity and input energy on the dehydrogenative coupling of methane were investigated. The parameter “energy efficiency” was introduced to examine the coupling of the input energy and the dehydrogenative coupling of methane. The experimental results show that positive corona gives higher energy efficiency than negative corona. When the positive corona was chosen, C2 yield per pass was 31.6% and acetylene yield per pass was 30.1% with 44.6% methane conversion at an input energy density of 1788kJ/mol and a pulse repetition frequency of 66Hz. The function of input energy density towards methane conversion may be expressed as a formula of-In(1-X) =k (PIF). In the range of input energy employed, C2 yield is proportional to input energy density, but energy efficiency drops off with increasing input energy density.

Study on the Methane Coupling under Pulse Corona Plasma by Using CO2 as Oxidant

In this paper, the conversion of CO2/CH4 by using pulse corona plasma was studied at atmospheric pressure and ambient temperature. The effects of ratio of CO2/CH4, pulse voltage and repeated frequency of plasma discharge were first studied in the system.

Scale-Up Synthesis of Hydrogen Peroxide from H2/O2 with Multiple Parallel DBD Tubes

The scale-up synthesis of H2O2 from H2/O2 via a dielectric barrier discharge (DBD) under ambient conditions was studied. A plasma reactor consisting of multiple parallel DBD tubes was designed to scale up the H2O2 synthesis. The number of tubes had no significant effect on the discharge mode, and no decay occurred in H2O2 selectivity during the scale-up process. These advantages made this technology more stable and efficient. The reactors energy efficiency increased with the number of tubes and reached 136 g H2O2/kWh in the four-tube reaction. The total energy efficiency was limited by the extremely low energy transfer efficiency of power supply, and might be enhanced by optimizing the impedance matching between the power supply and the reactor load. As a result, an assembly of multiple DBD tubes may provide a viable route for the scale-up synthesis of H2O2 by a non-equilibrium plasma.

Effects of Hydrogen on the Methane Coupling under Non-Equilibrium Plasma

In this paper, hydrogen is first utilized in the study on methane coupling under non-equilibrium plasma. Results indicate that the addition of hydrogen is beneficial to the methane coupling so as to increase the conversion rate of methane and the yield of C2 hydrocarbon with a gradual increase in the addition of hydrogen in a certain range of proportionality. This conclusion explores a new route of hydrogenated methane coupling.

Synergism of Plasma and Catalyst on the Dehydrogenative Coupling of Methane

At atmospheric pressure and ambient temperature, pulse corona induced plasma was used as a new method for dehydrogenative coupling of methane. The synergism of plasma and catalyst on dehydrogenative coupling of methane was investigated. Experimental results have revealed that the synergism does exist, when positive corona within a suitable power range and an intermediate pulse repetition frequency (PRF) for a loaded γ-Mn2O3/γ-Al2O3 catalyst were chosen. In respect to the mechanism approach, a tentative model for general pathway was proposed to explain the role of plasma and catalyst partaking in the process of methane decomposition and C2 products formation.

The Formation of Ethane from Carbon Dioxide under Cold Plasma

Pulsed-corona plasma has been used as a new method for ethane dehydrogenation at low temperature and normal pressure using carbon dioxide as an oxidant in this paper. The effect of carbon dioxide content in the feed, power input, and flow rate of the reactants on the ethane dehydrogenation has been investigated. The experimental results show that the conversion of ethane increases with the increase in the amount of carbon dioxide in the feed. The yield of ethylene and acetylene decreases with the increase in the yield of carbon monoxide, indicating that the increased carbon dioxide leads to the part of ethylene and acetylene being oxidized to carbon monoxide. Power input is primarily an electrical parameter in pulsed-corona plasma, which plays an important role in reactant conversion and product formation. When the power input reaches 16 W, ethane conversion is 41.0% and carbon dioxide conversion is 26.3%. The total yield of ethylene and acetylene is 15.6%. The reduced flow rate of feed improves the conversion of ethane, carbon dioxide and the yield of acetylene, and induces carbon deposit as well.

Preparation of TiOx/γ-Al2O3 Catalyst on Powdery γ-Al2O3 by Using Reactive Sputtering Deposition

A layer of TiOx was deposited on powdery γ-Al2O3 by using flat-target magnetron sputtering in microwave electron cyclotron resonance plasma. A vibrator was developed to coat the γ-Al2O3 particles evenly by TiOx. The conversion efficiency of methane and both the yield and the selectivity of C2 hydrocarbons and C2H2 were revealed to be superior to that by conventional chemical method. The use of vibrator is effective.