Blau gas

Rarely used or produced today, it was manufactured by decomposing mineral oils in retorts by heat, and compressing the resulting naphtha until it liquefied.

Blau gas contains about 50% olefins (alkenes), 37% methane and other alkanes, 6% hydrogen, while the rest is air.

It was historically stored in steel cylinders for shipment, and, around the turn of the century, had the advantage of possessing the highest specific energy of all artificially produced gases.

In contrast to the procedure for oil gas, which was produced by the Pintsch company from 1909, was also shipped in steel cylinders and had distillation temperatures of 900 to 1000 degrees Celsius to gasify the oil as completely as possible, the Blaugas process used lower temperatures of 550 °C to 600 °C and greater precompression.

Easily condensable (gasoline-like) hydrocarbons were separated in the process (initially by additional cooling) before final compression in the liquefied gas cylinders.