Enthalpy Probe Diagnostics of Steam/Argon Plasma Jet

DC plasma torch with argon/water stabilization features extreme properties of the exiting plasma jet. The plasma mass flow rate is very low while the temperature reaches very high values. Plasma properties were measured by enthalpy probe connected to a mass spectrometer. The measurements of enthalpy, temperature, density and dynamic pressure were carried out for three different arc currents and at atmos-pheric pressure. The dependences of plasma characteristics on arc current were shown

Diagnostics of Plasma Jet Generated in Water/Argon DC Arc Torch

Thermal plasma jet generated by the torch with water/argon stabilized arc was investigated. Plasma torches of this type have been used for plasma spraying, waste treatment and gasification of organic materials. Electric probes, enthalpy probe, and schlieren photography were used for diagnostics of the jet in the region downstream of the torch exit. Information about structure and shape of plasma jet was evaluated from the measured data. Large extent of radial plasma spread and high level of turbulence were found from both the schlieren and the probe diagnostics. Plasma temperature corresponding to measured ion saturation currents was determined using calculated composition of plasma assuming ex-istence of local thermodynamic equilibrium

Vision-based tomographic reconstruction of emissivity distribution in asymmetric thermal plasma

We report an original on-line optical diagnostics technique for the vision-based tomographic reconstruction of emissivity distribution in asymmetric thermal plasma using CCD cameras. The least-square QR decomposition (LSQR) method has been employed to solve the inverse ill-posed problem of the reconstruction efficiently. A numerical case is used for validating the diagnostics technique, and effects of different CCD camera combinations and measurement errors on the reconstruction performance are examined. Results show that the emissivity distribution of thermal plasma can be reconstructed well with a short reconstruction time for different noisy input data, proving the feasibility and the on-line ability of this technique to characterize the asymmetric plasma medium

Plasma gasification of refuse derived fuel in a single-stage system using different gasifying agents

The renewable evolution in the energy industry and the depletion of natural resources are putting pressure on the waste industry to shift towards flexible treatment technologies with efficient materials and/or energy recovery. In this context, a thermochemical conversion method of recent interest is plasma gasification, which is capable of producing syngas from a wide variety of waste streams. The produced syngas can be valorized for both energetic (heat and/or electricity) and chemical (ammonia, hydrogen or liquid hydrocarbons) end-purposes. This paper evaluates the performance of experiments on a single-stage plasma gasification system for the treatment of refuse-derived fuel (RDF) from excavated waste. A comparative analysis of the syngas characteristics and process yields was done for seven cases with different types of gasifying agents (CO2 + O2, H2O, CO2 + H2O and O2 + H2O). The syngas compositions were compared to the thermodynamic equilibrium compositions and the performance of the single-stage plasma gasification of RDF was compared to that of similar experiments with biomass and to the performance of a two-stage plasma gasification process with RDF. The temperature range of the experiment was from 1400 to 1600 K and for all cases, a medium calorific value syngas was produced with lower heating values up to 10.9 MJ/Nm3, low levels of tar, high levels of CO and H2 and which composition was in good agreement to the equilibrium composition. The carbon conversion efficiency ranged from 80% to 100% and maximum cold gas efficiency and mechanical gasification efficiency of respectively 56% and 95%, were registered. Overall, the treatment of RDF proved to be less performant than that of biomass in the same system. Compared to a two-stage plasma gasification system, the produced syngas from the single-stage reactor showed more favourable characteristics, while the recovery of the solid residue as a vitrified slag is an advantage of the two-stage set-up.publisher: Elsevier articletitle: Plasma gasification of refuse derived fuel in a single-stage system using different gasifying agents journaltitle: Waste Management articlelink: http://dx.doi.org/10.1016/j.wasman.2015.07.014 content_type: article copyright: Copyright © 2015 Elsevier Ltd. All rights reserved.status: publishe