Oil refineries
The furnace
Refinery gas is burnt inside the furnace to heat the oil.

The furnace heats the crude oil to 370°C before it is pumped into the bottom of the distillation column.

The oil is pumped through pipes which line the inside of the furnace and is heated by large gas burners. The hot oil stays inside the pipes and, naturally, never goes anywhere near the flames.

When it passes into the bottom of the distillation column at this temperature, most of the hydrocarbons boil off. They pass up the distillation column as gases where they are cooled, condensed and collected.

Refinery gas. The burners use refinery gas. This is a mixture of light, gaseous hydrocarbons that have been collected from various refinery processes. The mixture is not suitable for further processing and it is more cost effective to use it as a fuel on the refinery than to separate the gases. There is a main pipe running around the refinery which collects the refinery gas and delivers it to the furnaces, electricity generators and steam generators.