Expand Hydrocracker Operating Window Through Process ...

system. The Z-803 hydrocracking catalyst provides a unique combination of activity andselectivity and operating flexibility. It produces increased heavy naphtha and distillateselectivity compared to Z-753 at constant conversion. This does not come at the expenseof increased hydrogen consumption, as the reduced gas make of Z-803 compensates forthe increased hydrogen requirement for distillate saturation. The kinetic and economicanalysis of the different options showed that the Z-863/Z-803 stacked bed crackingcatalyst system provided the flexibility and robustness required by DPRC, and at the sametime it reduced gas-make, which enabled the unit to increase throughput at the currentgas handling constraint.The team also evaluated the optimal conversion level for maximizing diesel or naphthayields. Figure 9 shows the operational range for the Z-863/Z-803 catalyst system for theDPRC hydrocracker. This figure demonstrates that there is a gross conversion range formaximum diesel production. The figure also shows that to maximize naphtha yield, theunit can operate at maximum conversion up to its gas-handling limit.Figure 9 – Product Yield vs. Gross ConversionFigure 9 shows the product yield versus gross conversion. Volume percent product yield is on theY axis and volume percent gross conversion is on the X axis. The plot shows the gross conversionrange at which the unit can operate to maximize diesel production. To maximize naphtha yield,the unit can maximize conversion up to its gas-handling limit.AM-10-145Page 11