Tars removal by non-thermal plasma and plasma catalysis

Abstract

The gasification of a fuel or biomass is an industrial process that is utilized for synthesis gas (syngas) production. The syngas can be used to generate electricity, but after gasification it is often polluted with tars and various other pollutants. Therefore, the syngas must be cleaned before further use. The objective of this paper was to investigate the potential of removing the tars by non-thermal plasma generated by atmospheric pressure dielectric barrier discharge in combination with various packing materials (TiO 2 , Pt/γ-Al 2 O 3 , γ-Al 2 O 3 , glass beads). Naphthalene was used as a model polyaromatic tar compound. The effect of discharge power, carrier gas and packing material on naphthalene removal was investigated and gaseous and solid by-products were analysed by means of FTIR spectrometry. In ambient air, a naphthalene removal efficiency of 88% and 40% was achieved for 320 J l −l with and without the catalyst, respectively. The maximum removal efficiency of almost 100% was observed with a TiO 2 catalyst and oxygen carrier gas. CO, CO 2 , H 2 O and HCOOH were identified among the products, as well as more complex compounds, such as 1,4-naphthoquinone and phthalic anhydride.

Tar Removal by Nanosecond Pulsed Dielectric Barrier Discharge

“…Four compounds derived exclusively from naphthalene have also been detected: phthalic anhydride, 1,4-naphthoquinone, 1-naphthol, and 2-naphthol. They were also all detected by other researchers in different studies concerning tar removal in plasma-catalytic systems [4,[26][27][28][29]33,51]. In the case of the Ni catalyst incorporated in the inner ceramic tube, no aliphatic products were detected.…”

“…Number of gaseous components entering a reactor-similar to a real biomass producer gas, which was considered only in [9,21]; 2. Number of tar components-in this work 3 tar representatives were used together while in most cases only 1 or 2 are used [11,15,16,[22][23][24][25][26][27][28][29][30][31][32][33][34]. Excluding a few works performed on real biomass producer gas [9,14,21] only Kong et al [17], Eliott et al [10], Jamroz et al [12] and Yu et al [35] used at least 3 tar components, but in nitrogen, argon and oxygen as a plasmaforming gas; 3.…”

“…Samples were taken at five equally spaced points along the inner ceramic tube. Usually, as in the work of Cimerman et al [28], the identification of the exact decomposition by-products of naphthalene alone by using FTIR spectroscopy, especially those in the solid phase, is not trivial. Then, often only functional groups can be determined.…”

Coupled Plasma-Catalytic System with Rang 19pr Catalyst for Conversion of Tar

“…There are many technologies used for the purification of pyrolysis gas from volatile organic compounds and tars. The following methods can be distinguished: catalytic oxidation, filtration and biofiltration, adsorption on activated carbon, electrostatic precipitation and plasma techniques 8–12 . Decomposition of tars has been conducted with the use of natural and synthetic materials.…”

“…Synthetic catalysts lead to a higher conversion of tars 7 , but they are more expensive and more susceptible to sulfur deactivation and soot contamination. Nowadays, the most common catalytic systems used and investigated for tar decomposition are Ni, Rh, Pt, Fe based catalysts 7,12 . Some literature results on the destruction of model compounds with a catalyst or the use of plasma are presented in Table 1.…”