Gasoline by Pressure Cracking: Heavy Residue Distilled at 650-850 °F under 4-5 Atmospheres (Burton, US 1,049,667)

Straight distillation leaves most of a barrel of crude as heavy oil. Burton's 1913 patent turns that residue into gasoline: distil it hot while its own vapour is held at 4 to 5 atmospheres, all the way through the condenser. The heat and pressure break the heavy oil into light oil. Cracked gasoline is the first rung toward high-octane fuel. Feed: the fuel-oil and gas-oil residue left after the light cuts, boiling at about 600 to 700 °F (claim: above 500 °F). Source: W. M. Burton, US 1,049,667 (1913), assigned to Standard Oil (Indiana). Not given: charge size, run time, yield. Burton claims the gasoline stays in the paraffin series; that is his claim. A fired still under pressure needs a working safety valve. Picture: the patent drawing.