Novel Carbon Based Catalysts for the Reduction of NO with Coke Petroleum Ashes as Active Phase: Synthesis and Characterisation
M. J. LГЎzaro, A. Boyano, M. E. GГЎlvez, E. GarcГa-BordejГ‰ and R. Moliner
Instituto de Carboquimica CSIC, Miguel de Luesma Castán 4, 50018 Zaragoza (Spain)
E-mail: mlazaro@icb.csic.es
Аннотация
Carbon-based catalysts in powder, briquette and monolith forms have been prepared. Powder and briquette samples have been obtained from low-rank coal whereas monolith samples were prepared by coating cordierite monoliths with a blend of two polymers, namely, furan resin and polyethylene glycol. Vanadium was impregnated in these carbon-based catalysts by equilibrium adsorption using the ashes of a petroleum coke (PCA) as precursor and they were tested in the SCR of NO at low temperature. PCA contains around 23%V, 3 % Fe and 3 % Ni among other transition metals and this use is an undeniable good way for its revalorisation. As-prepared catalysts have demonstrated a considerable efficiency which was enhanced by pre-oxidizing treatments and an increase of vanadium loading. The presence of oxygen surface functionalities is of key importance to achieve an adequate distribution and fixation of the active phase while an excess in vanadium loading can even cause pore blockage decreasing the total efficiency. External diffusion and pressure drop coefficients were calculated for the three kinds of catalysts. As expected, powder catalyst shows the highest pressure drop while briquette and monolith samples show lower pressure drop values with no sign of diffusion limitations. For this reason, these structurated catalysts are considered to be more suitable for industrial applications.
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