Blending Light Hydrocarbons with Crude · API MPMS Ch. 12.3
Why light/heavy blends shrink, the API MPMS 12.3 correlation, and its valid ranges
When a light hydrocarbon is blended into crude, the small light molecules pack between the larger crude molecules, so the blend volume is less than the sum of the parts. API MPMS 12.3 predicts that loss.
S = 4.86×10⁻⁸ · C · (100−C)^0.819 · G^2.28, with S = shrinkage % of ideal volume, C = light-component vol %, G = API gravity difference.
1–99% light component and 10–100° API gravity difference (Table 3). Outside these, the correlation is extrapolated.