Destruction of Toluene, Naphthalene and Phenanthrene as Model Tar Compounds in a Modified Rotating Gliding Arc Discharge Reactor

Abstract

Tar removal is one of the greatest technical challenges of commercial gasification technologies. To find an efficient way to destroy tar with plasma, a rotating gliding arc (RGA) discharge reactor equipped with a fan-shaped swirling generator was used for model tar destruction in this study. The solution of toluene, naphthalene and phenanthrene is used as a tar surrogate and is destroyed in humid nitrogen. The influence of tar, CO2 and moisture concentrations, and the discharge current on the destruction efficiency is emphasized. In addition, the combination of Ni/γ-Al2O3 catalyst with plasma was tested for plasma catalytic tar destruction. The toluene, naphthalene and phenanthrene destruction efficiency reached up to 95.2%, 88.9%, and 83.9% respectively, with a content of 12 g/Nm3 tar, 12% moisture, 15% CO2, and a flow rate of 6 NL/min, whereas 9.3 g/kW·h energy efficiency was achieved. The increase of discharge current is advantageous in terms of decreasing black carbon production. The participation of Ni/γ-Al2O3 catalyst shows considerable improvement in destruction efficiency, especially at a relatively high flow rate (over 9 NL/min). The major liquid by-products are phenylethyne, indene, acenaphthylene and fluoranthene. The first two are majorly converted from toluene, acenaphthylene is produced by the co-reaction of toluene and naphthalene in the plasma, and fluoranthene is converted by phenanthrene.

The Effect of Packing Material Properties on Tars Removal by Plasma Catalysis

“…Finally, gaseous as well as solid compounds identified in the FTIR spectra based on detailed analysis of functional groups were confronted with the compounds reported as by-products in the works of other authors related to naphthalene decomposition by plasma and plasma catalysis [24,33,35,36,40,44,93,[100][101][102][103][104]. The comparison showed a good match and supported our findings.…”

“…Indeed, several discharges have been employed and investigated in the naphthalene removal process by plasma catalysis: corona discharge [35,36], dielectric barrier discharge (DBD) [37][38][39][40][41][42][43], gliding arc discharge [44,45], and even plasma jet [46]. The discharges have been combined with several catalytic materials, most frequently with Ni-based catalysts (Ni/γAl 2 O 3 [37,38,40,44], Ni/ZSM-5, Ni/SiO 2 [41] and Ni/Co-based catalyst [45]) due to their availability and selectivity towards formation of syngas constituents in catalytic processes [23]. However, their high activities are obtained only when operated at elevated temperatures (>780 • C) [47].…”

Tar Removal by Nanosecond Pulsed Dielectric Barrier Discharge

“…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. DBD plasma with a catalyst-this has been studied by many researchers [18] and is called a one-stage configuration since the catalytic material is in contact with the plasma.…”

“…Its advantage is instant high gas temperature and high reactivity due to the presence of energetic electrons, ions, and radicals. The largest amount of research is related to arc, dielectric barrier, corona and microwave discharges and their combinations with catalytic materials [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. An excellent review of the application of plasma-catalyst systems for tar removal was presented in [18] and most recent [19].…”

Editorial Catalysts: Special Issue on Plasma Catalysis

“…Likewise, Kong et al studied toluene, nathalene and phenanthrene destruction (as model tar compounds) in humid N 2 , in a rotating gliding arc reactor with fan-shaped swirling generator [16]. Tar destruction is one of the greatest technical challenges in commercial gasification technology.…”