Propane dehydrogenation cold box

Propane dehydrogenation (PDH) to propylene over a Pt/Cr catalyst, followed by a cold-box separation recovering liquid propylene from the H2-rich reactor off-gas, after US Patent 6,333,445 (Chart Inc., 2002). The refrigeration loop itself is not modeled — the cold box is represented here as a net cooling duty to condense the propylene, a bounded simplification. Unreacted propane recycle is not modeled either (reported as its own product stream).