Reactor catalyst carrier coating

Catalyst Carrier Coating Inside Bonded Reactors... 

The catalyst combines two essential ingredients found in eadier catalysts, vanadium oxide and titanium dioxide, which are coated on an inert, nonporous carrier in a layer 0.02- to 2.0-mm thick (13,16). Other elements such as phosphoms are also used. Ring-shaped supports are used instead of spherical supports to give longer catalyst life, less pressure drop though the reactor, and higher yields (17,18). Half rings are even better and allow more catalyst to be loaded (18). 

PA production received a further innovative impetus from the use of an alternative feedstock. In 1944/45, for the first time, Oronite Chemical Co. Standard Oil CA)) in the USA oxidized o-xylene in a salt-bath reactor to produce PA. The catalyst was a low-porosity carrier (silica quartz or silicon carbide), which was coated with 7 to 8% molten V2O5. The reaction temperatures of 450 to 600 °C were considerably higher than those used in the process. 

Liguras et al. investigated autothermal reforming of ethanol over ruthenium and nickel catalysts on structured supports such as ceramic foams and monoliths [212,213]. Conditions chosen were an O/C ratio of 0.61 and an S/C ratio of 1.5. The reaction was performed at a very high pre-heating temperature of the monoliths and consequently substantial conversion occurred even upstream of the reactor, which created a hot spot of up to 950 °C in the monoliths. A ceramic monolith coated with 5 wt.% ruthenium formed in addition to carbon oxides methane as the main byproduct, but there were also small amounts of acetaldehyde, ethylene and ethane [212]. When the S/C ratio was increased to 2.0, the by-products could be suppressed. Increasing the O/C ratio had a similar effect and also suppressed the methane formation. The ruthenium catalyst showed stable conversion for a 75-h test duration. Nickel/lanthana catalysts containing 13 wt.% nickel on a lanthana carrier showed similar performances with respect to activity, selectivity and stability [213]. 

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