Towers The Distillation Process

Towers, also referred to as columns, are one of the principal pieces of equipment of any processing facility. Towers are cylindrical steel vessels that are used for distilling raw materials in the produaion of such products as gasoline, diesel, and heating oil. The plant layout designer must understand the internal structure of a tower and how it operates to produce a satisfactory design.  

This chapter highlights the general requirements for tower plant layout design. It describes the internal workings of towers and provides the information required to orient nozzles locate instruments, piping, and controls and provide platforms and ladders for operator and maintenance access. 

Crude oil is of little commercial use when separated, or broken down, however, oil becomes one of the most valuable commodities in the world. Crude oil is a mixture of hydrocarbon compounds with a wide range of boiling points from 100° F (38° C) to 1,400° F (760° C). 

Separation, or distillation, is a process by which a liquid mixture is partially vaporized. The vapors are then condensed, separating the individual components of the mixture. As the temperature of crude oil is raised, the initial boiling point (IBP) is reached. As boiling continues, the temperature rises. The lightest material, butane, is produced first, at IBP, just below 100 F (38° C) the heavier materials are produced below 800° F (427° C). The residue includes everything above 800° F (427° C). Exhibit 10-1 shows the distribution of the different products at the various temperature ranges. 

The evolution of distillation towers is best explained in three basic steps  

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