Decaffeination Extraction Front: scCO2 Diffusion Kinetics

Supercritical CO2 decaffeination works by diffusing caffeine out through each bean's solid matrix and sweeping it away in flowing scCO2. This simulator models that with a real linear-driving-force approximation of Fick's second law for a spherical particle (Glueckauf's k_LDF = 15D_e/R_p²), coupled to quasi-steady plug flow through a fourteen-bin packed bed, so a genuine caffeine extraction front travels up the column exactly as it does in an industrial fixed-bed extractor. Pressure and temperature sliders set the partition coefficient and effective diffusivity from real physical trends — including the critical-point cutoff at 73.8 bar below which CO2 stops behaving supercritically — while bean radius and flow rate control the kinetics and the fluid-phase dilution that shapes the front.