Previous investigations have found that the plasma catalytic conversion of methane is a low-emperature process for the activation of methane, the major component of natural gas. In this paper, the production of acetylene via plasma catalytic conversion of methane over NaY zeolite is discussed. Hydrogen is produced as a by-product during this plasma catalytic methane conversion. A methane/hydrogen feed with oxygen as an additive and helium as a diluent has been studied in this investigation. The CH4/H2/O2 system is found to be more selective for the production of C2 hydrocarbons, compared to the CH4/O2, CH4/H2O, and CH4/CO2 systems reported previously. A higher hydrogen concentration feed is more favorable for acetylene formation. The selectivity and yield of C2 hydrocarbons are related to the hydrogen feed rate, gas temperature, concentration of oxygen additive, and flowrate. The highest yield of C2 hydrocarbons (32%) is obtained at the lowest flowrate used (10 cm3/s; residence time

Novel amorphous Ni-B catalysts supported on alumina have been developed for the production of hydrogen peroxide from carbon monoxide, water and oxygen. The experimental investigation confirmed that the promoter/Ni ratio and the preparation conditions have a significant effect on the activity and lifetime of the catalyst. Among all the catalysts tested, the Ni-La-B/γ- Al2O3 catalyst with a 1:15 atomic ratio of La/Ni, dried at 120℃, shows the best activity and lifetime for the production of hydrogen peroxide. The deactivation of the alumina-supported Ni-B amorphous catalyst was also studied. According to the characterizations of the fresh and used catalysts by SEM, XRD and XPS, no sintering of the active component and crystallization of the amorphous species were observed. However, it is water poisoning that leads to the deactivation of the catalyst. The catalyst characterization demonstrated that the active component had changed (i.e., amorphous NiO to amorphous Ni(OH)2) and then salt was formed in the reaction conditions. Water promoted the deactivation because the surface transformation of the active Ni species was accelerated by forming Ni(OH)2 in the presence of water. The formed Ni(OH)2 would partially change to Ni3(PO4)2.

Methane conversion in the presence of carbon dioxide was investigated under the conditions of dielectric-barrier discharge plasmas. Different from the previous investigations, the grounded electrode is covered by the dielectric material (quartz) in the present reactor design. The product contains gaseous hydrocarbons, syngas and oxygenates. No liquid hydrocarbons can be detected with the present reactor design. The oxygenates produced includes acetic acid, propanoic acid, ethanol and methanol. There exists an optimum feed ratio of CH4/CO2 to make the maximum selectivity of the objective oxygenate. The highest selectivity of acetic acid was 5.2% achieved at CH4 and CO2 conversions of 64.3% and 43.1%, respectively.

A diesel fuel additive has been synthesized from conversion of dimethyl ether(DME) using dielectric barrier dischargeŽDBD.plasma at atmospheric pressure and low temperatures. A high conversion of DME has been achieved. The product of such conversion is a mixture of hydrocarbons and oxygenates that can be used as high-performance diesel fuel additives. The maximum conversion of DME reached 47.2% with a selectivity of liquid product (a mixture of dimethoxy-containing hydrocarbons) more than 39.0% at 1208C and a 30 mlrmin flow rate of DME.