How do you optimize a trickle bed reactor for hydroprocessing?

Optimization parameters: hydrogen partial pressure (higher improves hydrogenation but increases compression cost), temperature (higher improves kinetics but accelerates deactivation, affects selectivity), space velocity (balance conversion vs throughput), H2/oil ratio (ensure adequate hydrogen availability, minimize recycle), and catalyst grading (use different activities along bed to manage exotherms and optimize selectivity). Challenges: liquid maldistribution, hot spots, pressure drop with deactivation. Use pilot plant data for scale-up with proper accounting for wall effects.