Catalyzed diesel cetane number
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It is well known that the cetane number of catalyzed diesel is very low. Is it possible to increase it without hydrogenation by adjusting the catalyst or the reaction conditions? Please discuss it.
No, even with hydrogenation, it only improves antioxidant capacity; it cannot increase the cetane number.
A comparative test is conducted between the sample diesel and a standard fuel prepared from hexadecane (whose cetane number is specified as 100) and α-methylnaphthalene (whose cetane number is specified as 0). When the ignition performance data of the sample diesel match those of a certain standard fuel, the volume percentage of hexadecane in that standard fuel constitutes the cetane number of the sample diesel. I think in theory, the reaction can be altered to change the cetane number. Hehe, I’m not quite sure either.
There must be a way under hydrogenation conditions. Technologies such as RICH developed by RIPP and MCI developed by FRIPP can both improve the quality of catalytic cracking LCO. For example, with the MCI technology, the cetane number of diesel can be increased by 10.9 units, while the sulfur content can be reduced from 7000 ppm to 5.8 ppm ； With RICH technology, the diesel cetane number can be increased by 10.4 units, and sulfur content can be reduced from 6000 ppm to 1.9 ppm.
Catalyzed diesel has a high content of olefins and aromatics, and it is essentially impossible to increase its cetane number without hydrogenation.
Diesel molecules are large, generally with more than 12 carbon atoms, so olefin components are basically not detected. :handshake
By making adjustments, the cetane number of diesel can be increased to a certain extent, though the increase is limited. It is advisable to use large-pore molecular sieve catalysts; moreover, the severity of the reaction conditions can be reduced appropriately in order to minimize the aromatic components in the diesel fraction, which results in a slight increase in the diesel’s cetane number. The cetane number of diesel can be increased entirely through hydroprocessing to achieve this goal. :handshake
It can be adjusted slightly, by a very small amount. It is mainly determined by the raw materials and the manufacturing process.
It’s practically impossible; among hydrocarbons, n-16alkanes have the highest octane number, whereas isomerized and unsaturated 16alkanes have a lower octane number. From the main reactions that occur in catalytic cracking (cracking, isomerization, aromatization, hydrogen transfer reactions), none of them contribute to increasing the cetane number of diesel. This post was last edited by chengkang on 2009-3-23 19:41]
I think the range of adjustment is very limited; improving the cetane number can be achieved by blending catalytic diesel with biodiesel, or by adding cetane number improvers.
I disagree with the view expressed on the second floor; hydrogenation can increase the cetane number of catalyzed diesel. The fact that unsaturated hydrocarbons become saturated is sufficient to prove this.
The improvement is not significant; without hydrogenation or blending, the cetane number of catalyzed diesel cannot meet the Euro 3 and Euro 4 standards.
The hydrofining antidetonation catalysts HT-1 and HIDW-1 can increase the cetane number by 5–7 units while reducing pour point. I suggest that if your plant does not have a hydrodenitration unit, you can use additives to increase the cetane number of diesel. Typically, refineries use isooctyl nitrate to increase the cetane number of diesel; this method is simple and does not affect other properties of the diesel. The typical addition amount is around 1000–2000 ppm, and the effect is quite significant. The original poster can consider it
Does catalytic charring without hydrogenation improve stability? What are the methods for removing oxygen, nitrogen, and sulfur?
The effect without hydrogenation is not significant; generally, the issue is resolved through oil blending.
Only by reducing the reaction temperature can the ratio of naphthenes to aromatics in the catalyzed diesel be decreased, thereby making it possible to increase the cetane number. . . Catalytic hydrotreating and upgrading of diesel can enhance and improve the cetane number. . . :lol
Adding a 16-octane number improver can increase the octane number
Generally, it is not possible to increase the cetane number of diesel, but the yield of diesel can be improved through factors such as catalyst activity.
Conventional hydrofining cannot significantly increase the cetane number of catalytic diesel; it can only improve its stability and color.