Cold box Process Flowsheets & Simulations
Explore 2 validated, solved Cold box simulation flowsheets in MaximaLabs — real components: propane, propylene, h2, methane, ethane, nitrogen. Open any one directly in your browser.
Solved via: PENG-ROBINSON.
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).
6 unit ops • PENG-ROBINSON
226 0
View & openMultistream exchanger: one core, three streams, one free outlet
A cryogenic cold box is not a network of two-stream exchangers — it is one brazed-aluminium core with several streams exchanging heat simultaneously, and the multistream exchanger models it as such. Three streams share this core: 300 mol/s of 300 K feed gas being chilled, 250 mol/s of 190 K residue gas being rewarmed, and 60 mol/s of 200 K cold liquid. You specify outlet temperatures for all but one — 225 K for the feed gas, 280 K for the residue — and the remaining stream is the free one: its outlet, 230.1 K, is not specified but SOLVED, because it is what closes the adiabatic energy balance across the core. That is the correct number of degrees of freedom for an adiabatic exchanger, and specifying all three would over-specify it. The 1.08 MW duty and a composite-curve pinch check against a 3 K minimum approach come with it, so a specification that would need heat to flow the wrong way is rejected rather than reported. Bounded: this is a thermal feasibility and duty model, not a mechanical design. There is no core geometry, no layer stacking, no fin type, no per-stream pressure drop from passage dimensions — a real cold box datasheet needs all of those, and a vendor computes them from proprietary correlations.
7 unit ops • PENG-ROBINSON
68 0
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