Diesel fuel, petroleum refining process

As catalysts, zeolites have found their most important application in petroleum refining processes. Their acid function is used in Fluid Catalytic Cracking (FCC), in hydroisomerisation of light alkane fraction as well as in ohgomerisation and isomerisation steps to upgrade the hquid fuels into gasohne and diesel. The combination of two different zeolites in the same industrial process is illustrated in the Shell-UOP TIP process an acidic zeolite, MOR, is used for isomerisation and the neutral LTA is used as molecular sieve for separation as shown in the scheme below (Figure 5.3). 

A major application of fluidized bed technology is to be found in the catalytic-cracking reactor, or Cat Cracker , which lies at the heart of the petroleum refining process. Here, the catalyst particles (which promote the breakdown of the large crude petroleum molecules into the smaller constituents of gasoline, diesel, fuel oil, etc.) are fluidized by the vaporized crude oil. An unwanted by-product of the reactions is carbon, which deposits on the particle surfaces, thereby blocking their catalytic action. The properties of the fluidized state are further exploited to overcome this problem. The catalyst is reactivated continuously by circulating it to another bed, where it is fluidized with air in which the carbon burns... 

Raw petroleum (crude oil) is extracted from underground around the globe in a variety of ways and refined for tens of thousands of applications in our everyday lives. Crude oil is refined into usable petroleum products through several unique processes. Fractional distillation is the process used to efficiently extract or "distill" products that are a mixture of chemicals such as gasoline, diesel fuel, and kerosene or may selectively extract pure chemical compounds or petrochemicals such as... 

On this basis, petroleum may have some value in the crude state but, when refined, provides fuel gas, petrochemical gas (methane, ethane, propane, and butane), fiansportation fuel (gasoline, diesel fuel, aviation fuel), solvents, lubricants, asphalt, and many other products. In addition to the hydrocarbon constituents, petroleum does contain heteroatomic (nonhydrocarbon) species, but they are in the minority compared to the number of carbon and hydrogen atoms. They do, nevertheless, impose a major influence on the behavior of petroleum and petroleum products as well as on the refining processes (Speight and Ozum, 2002). 

Hphis chapter presents results of a Chevron Research Company study sponsored by the U.S. Department of Energy (DOE) to demonstrate the feasibility of converting whole shale oil to a synthetic crude resembling a typical petroleum distillate. The synthetic crude thus produced then can be processed, in conventional petroleum-refining facilities, to transportation fuels such as high-octane gasoline and diesel and jet fuels. The raw shale oil feed used in this study is a typical Colorado shale oil produced in a surface retort in the so-called indirectly heated mode. 

Another area of environmental concern is the products themselves. Petroleum refining in the last 10 years has been driven by requirements for the composition of gasoline and diesel fuel that are continuously changed by environmental demands. Such considerations will have even stronger impact in the future. There are similar problems in the chemical process industries. The search for an environmentally acceptable substitute for Freon is a prominent present example. Another problem is polyvinyl chloride (PVC), which causes difficulties in incinerators. The question is, should we continue to produce PVC or should we find a substitute that is easier to dispose of Can we modify polymers in such a way that they cause fewer problems of pollution than they cause now These are major challenges for the profession, in both academia and industry. 

It is important to emphasize that all conventional motor fuels—petroleum gasolines and diesel—are produced by complex refining processes. These fuels are mixtures and contain hundreds of organic compounds. None is a single, pure substance. Similarly, almost all biomass-based liquid motor fuels contain numerous organic compounds, but in some cases can consist of relatively few compounds, as in the case of the methyl esters of fatty acids in biodiesel. The exceptions are the lower molecular weight alcohols and a few derivatives that can be used directly as neat motor fuels. They can easily be manufactured from biomass feedstocks as individual compounds. 

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