Direct air capture with solid-sorbent calcination + CO2 liquefaction

A Carbon Engineering-style DAC train: a fan draws ambient air (400 ppm CO2) through a liquid-KOH contactor (a fixed-recovery separator — the same simplification the existing carbon-capture example uses for chemical absorption, since no CO2-KOH electrolyte package exists) capturing ~75% of the CO2. The captured CO2 is causticized and precipitated into CaCO3 pellets by the real (unmodeled-in-detail) KOH/Ca(OH)2 loop — represented here as a matched pellet feed sized to the captured CO2 rate, since the generic reactor unit op can't itself produce a solid product (only a rotary kiln's decomposition path can, which is exactly what's used next). Those pellets calcine at ~977 degC in an indirectly-heated rotary kiln (real Arrhenius decomposition kinetics, Sullivan-Maynard-Valentine residence time), releasing pure CO2 that's compressed to ~20 atm and chilled to 250 K — above the real Span-Wagner CO2 saturation pressure at that temperature, so the solved outlet stream is genuine subcooled LIQUID CO2 (not just dense-phase pipeline gas) — while the CaO leaves for slaking and reuse (the lime side of the closed loop, out of scope for the same reason as the causticization step). Run the Carbon Footprint report on this example for the real Scope 1/2/3 CO2e + carbon-tax liability breakdown already built into this codebase's report generator.