Heating Oil

When crude oil is extracted from the earth it contains a vast mixture of organic
compounds, which range from very light hydrocarbons to extremely high molecular
weight species. In the refinery the crude oil is distilled and various distillation ‘cuts’
range from light fractions (gas and light solvents), fuel (gas oil), a lube cut, and the
heavy tractions (heavy fuel oil and asphalts). Hot oils come from the lube cut and after
further refining the hot oils are selected for viscosity (which partly defines the heat
transfer properties) and stability, and are branded and marketed as heat transfer fluids.