Jean Marie Cormier

Syngas production via methane steam reforming with oxygen: plasma reactors versus chemical reactors

Steam reforming with oxygen (SRO) is a combination of non-catalytic partial oxidation and steam reforming of methane, industrially used for syngas production. There are several models of the chemical reactors used for this purpose but in the last decade a new direction has developed - plasma devices. The aim of the present paper is to make a comparative analysis between the autothermal reformers, including their improved variants, and the plasma reactors. The study is conceived in terms of advantages and disadvantages coming from the exploitation parameters, methane conversion, selectivity, energy efficiency and investment costs. Although SRO by means of chemical reactors may be the most efficient, plasma reactors represent an incisive approach by their simplicity, compactness and low price.

Syngas production by plasma treatments of alcohols, bio-oils and wood

Exploitation of forest resources for energy production includes various methods of biomass processing. Gasification is one of the ways to recover energy from biomass. The Syngas produced from biomass can be used to power internal combustion engines, or, after purification, to supply fuel cells. The paper is summarizing results obtained through a non thermal arc plasma reactor at laboratory scale. A stationary discharge (I = 150mA) is used to perform physical diagnostics and also chemical analysis. The arc is formed between two electrodes made of graphite. We first present results on plasma-steam reforming of alcohols and bio-oils mixed in water. The outlet gas compositions are given from various alcohols and-bio-oils obtained at different experimental conditions. The second part of the paper is dedicated to a direct plasma treatment of wood (beech) at laboratory scale. One of the electrodes is surrounded by wood. The final part of the paper is a general discussion about efficiencies and comparisons of plasma treatments presented. The results obtained are discussed by considering the steam reforming reactions and the water gas shift reaction.

Non Thermal Plasma NOx Remediation: From Binary Gas Mixture to Lean-Burn Gasoline and Diesel Engine Exhaust

Abstract Experiments are presented on the plasma removal of NOx (sum of NO and NO2 concentrations) and hydrocarbons in atmospheric pressure gas streams by sub-microsecond pulsed dielectric barrier discharge processing. This investigation presents the effects of electrical input energy, hydrocarbon addition, and water addition on the NOx chemistry and by-products formation. Exhaust gas mixtures with composition containing up to seven gases (CO, CO2, NO, O2, H2O, C3H6, N2) were synthesized. The objective is to use synthetic gas exhaust simulating diesel and Lean Burn gasoline engine exhaust with propene as a reductant agent. It was established that the observed chemistry in the plasma includes conversion of NO to NO2 as well as the partial oxidation of hydrocarbon. In a given reactor under identical gas composition and equivalent energy density deposition, experimental results show that the main parameter which controls the efficiency of the plasma process is the energy deposition mode. The best results on NOx and hydrocarbon removal efficiencies have been obtained at low input energy per pulse and high discharge frequency. NOx removal improves with increasing input energy deposition and the presence of water in the gas mixture appears to essentially enhance the chemistry process efficiency, reducing by this way the energy cost of the processes. For example, for an input energy density of 27 J/L, the fraction of NOx removed was about 60% with an energy cost less than 30 eV/molecule in the case of simulated diesel engine exhaust. The data obtained suggest that aldehydes (CH2O and CH3CHO) are formed in concert with NO oxidation to NO2 in the plasma phase. Methyl nitrate (CH3ONO2) and nitromethane (CH3NO2) are the main R-NOx compounds produced and small amounts of nitrous acid (HNO2) and formic acid (CH2O2) were also detected.

Degradation of Organics Compounds and Production of Activated Species in Dielectric Barrier Discharges and Glidarc Reactors

Major sterilization mechanisms are related to atoms and radicals, charged particles, excited molecules, ozone, and UV radiation. The ROS (Reactive Oxygen Species) are well known as evildoers. These species are easily created in ambient air and water and they live long enough to reach the cell and attack the organic matter. Test molecules conversion in dry and wet air is studied using Dielectric Barrier Discharge (DBD) and Gliding Arc Reactors (GAR). The effects of temperature and energy deposition into the media on the active species production and then on the organics compounds degradation are presented for two non thermal plasma reactors: DBD and GAR. Main production species investigated are OH, O3, NOx, CO and CxHyOz by-products. It is shown from experiment analysis that the reactive species production is quite different from one reactor to another. GAR and pulsed DBD are two chemical processing ways in which the temperature of heavy species in ionized gas is determinant. By reviewing the species production obtained from both reactors, a discussion is open about plasma decontamination.

Plasma-assisted Diesel Oxidation Catalyst: Laboratory and bench scale investigations for CO and HC light-off temperature and nox remediation

Summary form only given. A key feature of Diesel Oxidation Catalyst (DOC) is its ability to efficiently oxidize CO and hydrocarbons (HCs) at the diesel exhaust temperature levels. While the DOC technology has progressed to the point where CO and HCs emissions can be drastically reduced, there remain issues of cost and low temperature activity i.e. cold start engine regime. Recent development researches try to adapt a cost effective integrated solution combining non-thermal plasma (NTP) and DOC technology for diesel applications.

Atmospheric Pressure Low-Current Plasma for Syngas Production From Alcohol

An atmospheric pressure low-current arc discharge between graphite electrodes with conical geometry in a liquid ethanol/water mixture was investigated. Syngas production was demonstrated over large experimental conditions. In this paper, we focus on discharge aspects. It is shown from pictures that the behavior of a low-current arc discharge with consumable electrodes represents nonstationary plasma.