AM-01-51 INDUSTRIAL PERFORMANCE OF ADVANCED PALLADIUM CATALYST FOR LIQUID PHASE SELECTIVE HYDROGENATION OF TRACE DIOLEFINS IN FCC BUTENES

Description:

With the impending phase-out of MTBE, alkylation and butene dimerization processes are among the most practical options for increasing gasoline pool octane while minimizing RVP. Either FCC or steam cracker butenes streams can be used as feedstock for these processes. However, palladium catalyzed pretreatment of these streams is necessary to reduce diolefin concentrations. It is also desirable in many cases to isomerize butene-1 to butene-2 to produce higher octane products. An innovative palladium catalyst (Procatalyse LD-267R) has demonstrated very high activity for both selective butadiene hydrogenation and butene-1 isomerization in liquid-phase units. Industrial results indicate that this catalyst can reduce butadiene to typical alkylation feed specifications at significantly higher space velocities than conventional palladium catalysts at similar operating temperatures. Isomerization of butene-1 to butene-2 is also an important performance measure for selective hydrogenation units feeding HF alkylation or butene dimerization (isooctane) units. High isomerization can also increase throughput for sulfuric acid alkylation units that are rate limited by cooling constraints. Isomerization is typically limited to 30-60% with conventional palladium catalysts. However, the industrial results for LD-267R show isomerization consistently above 70%. The high activity level demonstrated by LD-267R in industrial operation allows significantly higher reactor space velocities for reactors currently using conventional palladium catalyst. This can allow operators to increase throughput for existing selective hydrogenation units without the expense of additional reactor capacity. Where additional throughput is not desired, a reduced catalyst loading can be used to reduce working capital investment or longer cycles can be achieved with full catalyst charges. In addition, alkylation and dimerization unit products have greater blending value because of the higher octane resulting from an increased butene-2 to butene-1 ratio.