Catalyst metal loadings, coal

W. Ding, J. Liang and L. L. Anderson. Depolymerization of waste plastics with coal over metal-loaded silica-alumina catalysts, Fuel Processing Technology, 49, 49-63 (1996). 

Selective Catalytic Reduction (SCR) using ammonia as the reductant provides NOx reduction levels of greater than 80%. Three types of catalyst systems have been deployed commercially noble metal, base metal and zeolites. Noble metals are typically washcoated on inert ceramic or metal monoliths and used for particulate-free, low sulfur exhausts. They function at the lower end of the SCR temperature range (460-520°F) and are susceptible to inhibition by SOx [14]. Base metal vanadia-titania catalysts may either be washcoated or extruded into honeycombs [11]. Typically washcoated catalysts are only used for treating particulate-free, clean gas exhausts. Extruded monoliths are used in particulate-laden coal and oil-fired applications. The temperature window for these catalysts is 600-750°F. Zeolites may also be washcoated or extruded into honeycombs. They function at relatively high temperatures of 650-940°F [15]. Zeolites may be loaded with metal cations (such as Fe, Cu) to broaden the temperature window [16]. 

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