Hydrotreating processes

S-compounds, N-compounds and M (Metal) compounds have different reactivities and chemistry depending on the boiling ranges of fractions in which they are found. Thus, specific processes have been developed for the removal of each of these impurities. These are classified as hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodemetallation (HDM) processes, respectively. These are in turn subdivided into processes, which are optimized for the boiling range of the particular feedstock being treated. 

M-compound impurities are found particularly in high boiling feedstocks, such as atmospheric and vacuum residues. Thus, HDM processes are tailored for high boiling and very viscous feedstocks. Nevertheless, trace amounts of M compounds in the gas oil must not be overlooked since they cause the catalyst deactivation in long run. 

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Hydrotreating processes are applied to finished products to improve their characteristics sulfur content, cetane number, smoke point and the aromatics and olefins contents. 

In regard to kerosene, the hydrotreating processes are used to reduce aromatics in order to improve the smoke point. 

Table 10.20 summarizes the main characteristics of hydrotreating processes. 

Hydrotreating reduces the sulfur content of all the products. With hydrotreated feeds, more of the feed sulfur goes to coke and heavy liquid products. The same sulfur atoms that were converted to H S in the FCC process are also being removed first in the hydrotreating process. The remaining sulfur compounds are harder to remove. The heavier and more aromatic the feedstock, the greater the level of sulfur in the coke (Table 2-7). 

DESUS A hydrotreating process developed and offered by VEB Petrolchemisches Kombinat Schwedt. Operated in the Schwedt oil refineiy, Germany, since 1988. 

Ferroflning A mild hydrotreating process for purifying lubricating oils. The catalyst contained cobalt, molybdenum, and iron (hence the name). Developed by the British Petroleum Company and first operated in Dunkirk, England in 1961. 

Hydrobon A catalytic petroleum hydrotreating process, developed by UOP and formerly licensed jointly with the Union Oil Company of California under the name Unifining. 

HYVAHL A hydrotreating process for upgrading petroleum residues. Developed by the Institut Frangais du Petrole. Three units were operating in 1996. See also TERVAHL. 

ISAL A hydrotreating process for removing sulfur and nitrogen compounds from petroleum fractions without reducing their octane values. Developed by Intevep SA, the research and technology arm of Venezuela s state petroleum company PDVSA. A proprietary zeolite catalyst first saturates the olefins and then isomerizes them to higher octane-value compounds. 

LT Unibon A two-stage, catalytic hydrotreating process for removing deleterious components from naphtha without cracking it. Developed by UOP. 

Platreating [Platinum hydrotreating] A hydrotreating process used in oil refining, using a platinum catalyst. 

Figure 6 Hydrotreating process. Hydrogen reacts with hydrocarbon feed to remove sulfur from the stream. The formed hydrogen sulfide is steam-stripped from the product. (From Ref. 2.)...

Use of hydrocracking and hydrotreating processes that produce lower wastewater loadings than existing processes. 

Typical Process Conditions for Various Hydrotreating Processes"... 

In principle, the flowsheet of an industrial facility is similar to those of the different hydrotreating processes (Figure 5.2-42) [61]. The feedstock C4 cut rid of water is pressurized to about 15 to 20 bar by pumping, injected with a hydrogen-rich gas and then, preheated by heat exchange with the reaction effluent and by steam. In a downflow stream, it then enters the reactor, which operates in a gas-liquid mixed phase with one or more catalyst beds (palladium, rhodium on inert alumina). After cooling, the isomerization products are flashed... 

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