e-Fuels (Power-to-Liquids): rWGS + Fischer-Tropsch

The Power-to-Liquids / e-SAF pathway: captured CO2 and green hydrogen are converted to synthetic hydrocarbons. A reverse water-gas-shift reactor turns CO2+H2 into CO + H2O (solved to real chemical equilibrium), the water is knocked out, and the syngas feeds a Fischer-Tropsch reactor that builds a whole hydrocarbon slate via the Anderson-Schulz-Flory chain-growth law. The single knob that sets the product spectrum is the chain-growth probability alpha (here 0.90): a high alpha shifts the slate toward diesel/wax, a low alpha toward LPG/naphtha -- the reactor distributes the reacted carbon across n-paraffins C1..C8 (the tail lumped as C8 wax) with exact C/H/O atom balances, so it conserves atoms wherever the distribution is cut. Honesty notes (see flowsim/solver/unitops/fischer_tropsch.py): this is the standard yield/selectivity FT model (ASF + specified CO conversion), not a mechanistic kinetic or slurry/fixed-bed hydrodynamic model; olefin/oxygenate co-products aren't split out (paraffins + water only); the raw syncrude effluent is delivered as-is (a real plant recycles the H2-rich tail gas and fractionates the liquid -- shown here as the reactor product, not a finished fuel cut); and the rWGS Keq is the representative high-temperature equilibrium magnitude.