2 Refining Processes and Lubricant Base Stocks

2.1 Crude Oil
2.2 Refining
2.3 Lube Refining Processes
2.4 Lubricating Base Stock Processing

Preface :

Crude oil is refined in two stages : refining of light products and refining of lubricating oils
and waxes. The refining of light products, which is concerned with all these substances except
lubricants, specialty products, waxes, asphalts, and coke, is accomplished at or slightly above
atmospheric pressure. At approximately 700 degrees Fahrenheit, the residuum from light
products refining has a tendency to decompose. Thus, the refining of lubricating oils and waxes
takes place under vacuum conditions and at temperatures under the decomposition point.

Refinery

There are two basic refining processes; separation and conversion. The separation process
selects certain desirable components by distillation, solvent extraction, and solvent dewing.
The conversion process involves changing the chemical structure of certain undesirable crude
oil components into desirable components. Conversion processes also include a degree of
removal of non-desirable species. The types of refining process are discussed in this chapter.

2.1 Crude Oil

A. Origin and Sources

Occurrence and Production of Petroleum

Petroleum is brought to the surface by drilling a hole in the Earth's crust and sinking pipes deep down through the impervious cap rock. Natural gas first comes out under high pressure. Then, petroleum is pumped out, collected in tanks and transported, for further processing.

Petroleum is a highly complex mixture of several hydrocarbons. Therefore, it does not have a
constant boiling point. Each fraction of petroleum has a different boiling range. Being a complex
mixture, it can seldom can be used as a fuel directly. It needed to be refined and separated into
simpler components.