Fuels hydrotreating

Unfortunately, cetane engine number values for kerosene vary from below 40 to about 50. For this reason, cetane engine testing is always recommended when kerosene is blended into diesel fuel. Hydrotreated kerosene will probably have a higher cetane number than more aromatic kerosene. 

Again citing the laboratory example above, the same JP-5 fuel hydrotreated shows improved stability to 300 plus minutes... 

By lowering the end point of the starting diesel fuel, hydrotreating the lower end point diesel fuel feed to ultra low sulfur levels is much easier. For example, when the 90% distillation point (T90) of diesel fuel is lowered by 20 °C, the required reactor size is only about half that needed for the full range feed. This diesel with lower T90 has another merit. It will produce less particulate matter in diesel exhaust gas. The downside of this approach would be the requirement for increasing the cracking capacity of the refinery to produce the required volume of diesel fuel with this T90. One solution is to revamp a VGO hydrotreater to mild hydrocracking service. 

Tables 5.29 and 5.30 show an example of the effects of hydrotreated diesel fuels on a diesel passenger car already having a low level of pollution owing to technical modifications such as sophisticated injection and optimized combustion. In the standard European driving cycle (ECE + EUDC), between...

Influence of hydrotreating a diesel fuel on particulate emissions. 

In the future, European and worldwide refining should evolve toward the production of relatively high cetane number diesel fuels either by more or less deeper hydrotreating or by judicious choice of base stocks. However, it is not planned to achieve levels of 60 for the near future as sometimes required by the automotive manufacturers. 

Finally it is likely that attention will be focused on emissions of polynuclear aromatics (PNA) in diesel fuels. Currently the analytical techniques for these materials in exhaust systems are not very accurate and will need appreciable improvement. In conventional diesel fuels, emissions of PNA thought to be carcinogenic do not exceed however, a few micrograms per km, that is a car will have to be driven for several years and cover at least 100,000 km to emit one gram of benzopyrene for example These already very low levels can be divided by four if deeply hydrotreated diesel fuels are used. 

Od condensed from the released volatdes from the second stage is filtered and catalyticady hydrotreated at high pressure to produce a synthetic cmde od. Medium heat-content gas produced after the removal of H2S and CO2 is suitable as clean fuel. The pyrolysis gas produced, however, is insufficient to provide the fuel requirement for the total plant. Residual char, 50—60% of the feed coal, has a heating value and sulfur content about the same as feed coal, and its utilisation may thus largely dictate process utdity. 

Diesel Fuel. Eederal diesel specifications were changed to specify a maximum of 0.05% sulfur and a minimum cetane index of 40 or a maximum aromatics content of 35 vol % for on-road diesel. Eor off-road diesel, higher sulfur is allowed. CARB specifications require 0.05% sulfur on or off road and 10% aromatics maximum or passage of a qualification test. Process technologies chosen to meet these specifications include hydrotreating, hydrocracking, and aromatics saturation. 

Recovering the bitumen is not easy, and the deposits are either strip-mined if they are near the surface, or recovered in situ if they are in deeper beds. The bitumen could be extracted by using hot water and steam and adding some alkali to disperse it. The produced bitumen is a very thick material having a density of approximately 1.05 g/cm. It is then subjected to a cracking process to produce distillate fuels and coke. The distillates are hydrotreated to saturate olefinic components. Table 1-8 is a typical analysis of Athabasca bitumen. ... 

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