Sub-Product

Atmospheric distillation residuum is the heaviest fraction obtained from the atmospheric distillation process. It consists of crude oil components with boiling points above approximately 650°F (343°C). These heavy components cannot be vaporized at atmospheric pressure and boiling temperatures, as they begin to crack or break down at those temperatures.

As a result, atmospheric distillation residuum remains in liquid form during the atmospheric distillation process and is collected from the “bottom” of the distillation tower. This fraction is typically sent to a secondary distillation tower, such as a vacuum distillation unit, where it is further distilled under reduced pressure to prevent cracking and produce lighter products.

In the absence of a vacuum distillation tower, atmospheric distillation residuum may be blended into residual fuel oil. The properties and characteristics of atmospheric distillation residuum can vary depending on the crude oil feedstock and refining conditions, but it generally has a high viscosity and density, making it unsuitable for use as a fuel or lubricant in its raw form.

Source: Brave Summarizer, Atmospheric Distillation Residuum, 6^th Sept 2024.