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Petroleum Refining Process, Thesis Paper Example

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Introduction

Petroleum products are derivatives of crude oil and have uses gasoline, diesel fuel, jet fuel, plastics, etc. Petroleum derivative products include adhesives, glues, soaps, asphalt chewing gums, cell phones, etc. The refining process allows operators and engineers to take raw crude and convert it into different chemical compositions by taking fractions off a distillation tower at different temperatures to create such products.

Raw Crude Oil enters the fractionation column at about 270C of which C14 to C20 diesel fuel oil cuts are made at this temperature. Diesel fuel oil has a very long carbon chain particularly alkanes and cycloalkanes and rich in aromatics. Diesel fuel oil is the heaviest fuel oil the can be achieved from crude oil. It has a flash point of approximately 40 C or 104 F.

Lubricating oil C20-C 70 drops at about 300 C from the fractionation column. One should keep in mind that the column is continuously being heated by the furnace and the trays are continuously being cooled to make the distillation or fractionation cuts to pull off each individual product. Lubricating oil on average has a viscosity of about 12cst at 100 C. Often companies add their own individual additives to promote the lubricant oils.

The heavy asphalt drops to the pot of the distillation/fractionation tower C70’s of which this product is used mainly to build roads and highways. No part of crude is ever wasted. Each cut off a tower is carefully made to maximize productivity and efficiency.

The jet fuel cuts are made at approximately 170 C where paraffin oils for lighting and heating are also taken off. These are the C10-C16 crude cuts.

The fractions begin to decrease in density and boiling points as the cuts are made at the top of the tower for gasoline, naphtha and the C1-C4 gases. At about 70 C the gasoline cuts are made off the fractionation tower, C5-C-10 (petro).

Naphtha, C5-C9 cuts are made at 20C just above the gasoline cuts. The gases C1-C4 are taken from the very top of the fractionation tower. Fractions increase in density and boiling point from the entrance of the raw crude and the lower fractions.

Fluid Cat Cracking

Fluid Cat Cracking is used to convert the high molecular weight, high boiling point hydrocarbon fractions of crude oil into gasoline and other usable petroleum derivatives. FCC hydro cracking replaced thermo cracking because it produced a higher yielded octane gasoline. Further it produces higher olefin gases that can be used for other products in the oil industry. When introducing feedstock for FCC it should have an initial boiling point of about 340 C and a molecular weight of 300-500. Exxon Mobil and Shell Motiva have one of the best state of art FCC units available to the cat cracking industries. Typically FCC units in the United States can produce approximately 6,000,000 barrels of feedstock per day.

Reformulated Gasoline

In order to produce reformulated gasoline, one must first reduce the sulfur, nitrogen and olefins from the naphtha feed stock. A H2 atmosphere must be introduced to the system and a buffer system which helps to reduce the SO2 content. This process is called reformation by which a catalyst is introduced into the process. The best catalysts that have been tested by Exxon Mobil Refinery have been combination catalysts of MoCo. In pilot plant testing, H2 was introduced at 1500 psi for a continuous run of 48 hours and the SO2 content was lowered from 88 ppm to 36 ppm with initial testing of GC 5890. (“Exxon Mobil-Nicole Kumar”)

Exxon Mobil-Nicole Kumar