Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

OP-V-13scale monolithic catalysts, best compositions of active components selected on the base ofextensive lab-scale studies in the reactions of methane and oxygenates (acetone, ethanol)steam reforming at short contact times in stoichiometric feeds were selected.A pilot tubular stainless steel reactor equipped with these catalysts and a front thermalshield was connected to the fuel/water evaporation unit with liquids supplied by the plungerpumps through nozzles, air being fed via a mass-flow controller. As fuels, acetone and anisole(methoxybenzene) of commercial grade and purified edible sunflower oil were used. Oxygencontent in the feed was varied in the range of 15-20%, H 2 O 0-18%, fuel 1-10%, flow rate upto 2 m 3 /h (contact times in the range of 5-50 ms at operating temperature).For all types of studied fuels, stable autothermal performance with the maximumtemperature at foil monolith up to 1000 °C was maintained with the inlet feed temperature aslow as 200 °C. In these conditions, the oxygen slip was not observed at all contact times. Themaximum syngas yield was up to 45% with H 2 /CO ratio increasing from ~ 0.8 to 1 withincreasing water content up to 10%. In products, along with CO 2 (in the range of 4-6%) someamount of CH 4 (1-2%) and olefins (up to 1%) were observed. This demonstrates occurrenceof cracking reactions as well. For longer contact times, and especially for feeds without water,ignition of fuels at the thermal shield was observed followed by the excessive carbondeposition at walls in the inlet part of the reactor. At a proper optimization of contact timesand feed composition, no coking was observed for hours-long pilot tests even for sunfloweroil as a fuel. No carbon build-up was observed for the monolithic evaporator as well. Additionof stack of gauzes or thin–foil monolith after thick–foil monolith allowed improving syngasyield and removing residual olefins from products. No spallation or cracking of the activecomponents supported on metallic substrates was revealed.Hence, pilot-scale tests in the reactor equipped with an original evaporator/mixer of liquidbiofuels (acetone and anisole as model fuels and edible sunflower oil as realistic fuel)revealed a high and stable performance in the autothermal reforming of monolithic catalystscomprised of heat-conducting fechraloy foil/gauze substrates with supported doped ceriazirconiacomplex oxides promoted by precious metals and/or Ni. This provides newpossibilities for transformation of a broad range of complex biofuels (such as products ofbiomass pyrolysis) into syngas.This work is supported by INTAS 05-1000005-7663 and INTAS YSF 06-1000014-5773Projects.193