Petroleum treatment secondary processes

These processes can be classified as primary or secondary processes. In this book, primary processes are used to describe processes in which crude petro-leum/products undergo only physical treatment. On the other hand, secondary processes describe processes in which petroleum/products undergo chemical transformations. 

In foregoing sections, we presented only the primary processes for petroleum treatment. It is important to note that all these processes are called primary processes because the petroleum only undergoes physical treatment. This means that chemical changes to the feed do not occur. All the processes we will describe in the sections of this chapter are referred to as secondary processes . This is intended to indicate that chemical changes of the feed occur during these treatments. 

Currently the use of full-scale GAC systems in the U.S. petroleum rebning industry is very limited. Some rebneries used GAC as the secondary treatment process but have discontinued the operations. Two examples are the Atlantic Richbeld (Arco) system near Wilmington, CA, and the British Petroleum (BP) system in Marcus Hook, PA [17]. 

Thus -alkanes (C10-C14) separated from the kerosene fraction of petroleum (by urea complexation or absorption with molecular sieves) are now used as one source of the alkyl group. Chlorination takes place anywhere along the chain at any secondary carbon. Friedel-Crafts alkylation followed by sulfonation and caustic treatment gives a more linear alkylbenzenesulfonate (LAS) which is soft or biodegradable. The chlorination process is now the source of about 40% of the alkyl group used for the manufacture of LAS detergent. 

Cyclization of 2 in concentrated sulphuric acid [14-16] predominantly leads to p-ionone (17). The reaction proceeds rapidly even below room temperature and, to avoid secondary reactions, is carried out continuously. The precooled streams of sulphuric acid and the solution of 2 in petroleum ether or liquid CO2 are mixed in a reactor and then quenched with cold water. Small amounts of a-ionone (18) can be separated off by distillation during isolation of the product. In the cyclization step large amounts of approximately 40% aqueous sulphuric acid are produced. Treatment to deal with this is expensive but is essential for environmental reasons. Organic impurities are broken down to carbon dioxide in a cracking furnace with heavy oil burners. In the course of this process, sulphuric acid is thermally converted into sulphur dioxide, which is reoxidized in the contact plant. 

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