Minggu, 27 Maret 2011

Chemical Processing

You can change one fraction into another by one of three methods:

Cracking breaks large chains into smaller chains.

Cracking
Cracking takes large hydrocarbons and breaks them into smaller ones.

There are several types of cracking:

Thermal - you heat large hydrocarbons at high temperatures (sometimes high pressures as well) until they break apart.
- steam - high temperature steam (1500 degrees Fahrenheit / 816 degrees Celsius) is used to break ethane, butane and naptha into ethylene and benzene, which are used to manufacture chemicals.
- visbreaking - residual from the distillation tower is heated (900 degrees Fahrenheit / 482 degrees Celsius), cooled with gas oil and rapidly burned (flashed) in a distillation tower. This process reduces the viscosity of heavy weight oils and produces tar.
- coking - residual from the distillation tower is heated to temperatures above 900 degrees Fahrenheit / 482 degrees Celsius until it cracks into heavy oil, gasoline and naphtha. When the process is done, a heavy, almost pure carbon residue is left (coke); the coke is cleaned from the cokers and sold.

An oil refinery or petroleum refinery is an industrial process plant where crude oilis processed and refined into more useful petroleum products, such as gasoline,diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas. Oil refineries are typically large sprawling industrial complexes with extensive pipingrunning throughout, carrying streams of fluids between large chemical processingunits. In many ways, oil refineries use much of the technology of, and can be thought of as types of chemical plants. The crude oil feedstock has typically been processed by an oil production plant. There is usually an oil depot (tank farm) at or near an oil refinery for storage of bulk liquid products.

An oil refinery is considered an essential part of the downstream side of thepetroleum industry.

Process Engineer