Thermal tar cracking enhanced by cold plasma – A study of naphthalene as tar surrogate

Abstract

Gasification has been proposed as a good solution for recovering energy from waste and biomass in the form of syngas. However, the presence of tar limits syngas applications. Tar model molecules have been removed by cold plasmas up to 400 • C, but to avoid syngas cooling tar removal above 600 • C is required. To investigate tar removal by cold plasma at higher temperatures, two sets of experiments were done, one to identify tar composition from MSW gasification, and a second one to crack in a nanosecond-pulsed corona plasma at high temperatures the most refractory tar compound found, naphthalene.In this paper, we report the first results of cold plasma for tar cracking at temperatures up to 1100 • C, revealing that this tandem can remove naphthalene completely at 800 • C, compared to the 1000 • C needed in case of thermal cracking alone. The synergy between plasma and thermal cracking is driven by higher energy densities when temperatures increase. However, this synergy stops when thermal cracking reactions predominate.

Numerical Investigations of a Fluidized Bed Biomass Gasifier Coupling Detailed Tar Generation and Conversion Kinetics with Particle-Scale Hydrodynamics

“…Nevertheless, it should be noted that the conversions of naphthalene, toluene, and phenol are not completely identical. In comparison to toluene and phenol, the conversion of naphthalene is the lowest as a result of the latter being a diaromatic, whose molecular structure is generally more stable than that of a monoaromatic . This is the reason why the content of naphthalene is usually much higher than that of toluene and phenol in gas products, as reported by Erkiaga et al in their experimental study .…”

“…In comparison to toluene and phenol, the conversion of naphthalene is the lowest as a result of the latter being a diaromatic, whose molecular structure is generally more stable than that of a monoaromatic. 43 This is the reason why the content of naphthalene is usually much higher than that of toluene and phenol in gas products, as reported by Erkiaga et al in their experimental study. 44 As a result of benzene being not only generated from the devolatilization process but also produced from the conversions of other tar compounds, the highest benzene yield occurs reasonably later than other tar compounds.…”

The EU Training Network for Resource Recovery through Enhanced Landfill Mining—A Review

“…At first, a review on the state of the art regarding the role of plasma in syngas tar cracking [92] was published, which was cited outside of NEW-MINE by two other review articles [93,94] mentioning the efficiency, but also the short lifetime and high costs of this technology, as well as a novel warm gas tar cleaning processing called OLGA. In a next step, naphthalene was used as a model tar molecule and Corona plasma-aided thermal cracking was demonstrated successfully for its removal at 800 • C [95]. This study was cited with respect to tar generation and conversion kinetics [96], regarding the required high temperatures of 1100 • C which represent a disadvantage compared to catalytic reforming [97], and as an example for thermal tar cracking [98].…”

Solid Oxide Fuel Cell Using Municipal Solid Waste Directly as Fuel: Biomass, Resin, Plastic, and Food Waste

“…However, tar and char produced in large amounts, especially from lignin and plastics, are not easily gasified, which degrades the fuel quality . This problem can be avoided by conducting gasification at temperatures greater than 1200 °C; however, this approach requires a high-temperature heat source that relies on combustion of the fuel. Therefore, at present, further increasing the fuel utilization efficiency is difficult.…”