Abstract
A catalyst with a high activity in tar conversion, impregnated on the ceramic hot gas filter material was developed. The aim of the experiments was to estimate the light-off temperature of the catalytic filter elements for naphthalene (tar model compounds) conversion and the long-term catalytic stability at a temperature of 700 °C. Configuration of the catalyst was optimized through improvements in coking resistance and long-term stability. The composition and morphology parameters of the filter material were considered. Both the impregnation methods and the composition of the impregnation solution were investigated and validated. The catalyst composed of Ni, Fe, Cr oxides, promoted with Pt (AlSi-Cat43-Pt), and impregnated on the ceramic-fiber filter composed of Al2O3(44%)/SiO2(56%) was found to be the most active catalyst. The designated catalyst was catalytically active at temperatures of about 700 °C, with a naphthalene conversion of around 93% over 95 h without catalyst deactivation. We found that the steam and gas compositions had an influence on the catalytic activity of the filter elements. The same catalytic filter was catalytically active for 115 h at a low concentration of H2O (10 vol%) and H2 (3 vol%) with a naphthalene conversion of 98% at 790 °C without significant deactivation.
Highlights
Biomass gasification, which is one of the technologies for the thermochemical conversion of biomass, is expected to be the key to the spreading of small and medium-sized biomass power plants around the world
The designated catalyst was catalytically active at temperatures of about 700 °C, with a naphthalene conversion of around 93% over 95 h without catalyst deactivation
We found that the steam and gas compositions had an influence on the catalytic activity of the filter elements
Summary
Biomass gasification, which is one of the technologies for the thermochemical conversion of biomass, is expected to be the key to the spreading of small and medium-sized biomass power plants around the world. Zhang et al [8] used α-Al2O3-based filter discs as a model of candle filter, and benzene as a model of tar compound, respectively They developed the nickel-activated catalytic filter (1 wt% Ni + 0.1, 0.5 or 1.0 wt% CaO, CaO was used as a promoter for the resistance to sulfur poisoning), using a urea precipitation process, which is categorized into method (b). In the raw gas will be removed by the sorption process, particulates and tars will be eliminated and converted These key components provide elimination of syngas impurities in only one device and make the entire gasification process more compact than conventional reactors of biomass gasification plants (Fig. 1). The current investigation focuses on the development of a catalytic candle filter that can remove the particulates in the product gas on its filter side (outside) and can convert tars into smaller organic compounds on its catalyst side (inside) (Fig. 2). Pt is well-known as a strong catalyst in the temperature range below 500 °C [13]
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