Hydrocracker

Comparing the overall concentrations of these different carbons designated generally as structural patterns , measured before and after a process such as FCC or hydrocracking (see Chapter 10), enables the conversion to be monitored the simple knowledge of the percentage of condensed aromatic carbon of a feedstock gives an indication of its tendency to form coke. 

Hydrocracking makes very good quality diesel fuels concerning the cetane number, cold behavior, stability, and sulfur content. However this type of stock is only available in limited quantities since the process is still not widely used owing essentially to its high cost. 

Process Atmospheric distillation Atmospheric distillation FCC Hydro- cracking Vis- breaking Coking Hydrocracking... 

Finally, note that hydrocracking is ideal for obtaining middle distillate cuts that can be used in jet fuel formulation. 

Different treatments provide lubricant bases having accentuated isoparaffinic structures these are the bases from hydrorefining, hydrocracking and hydroisomerization (see paragraph 10.3.2.2.c.2). 

Properly speaking, steam cracking is not a refining process. A key petrochemical process, it has the purpose of producing ethylene, propylene, butadiene, butenes and aromatics (BTX) mainly from light fractions of crude oil (LPG, naphthas), but also from heavy fractions hydrotreated or not (paraffinic vacuum distillates, residue from hydrocracking HOC). 

Feedstocks for this very flexible process are usually vacuum distillates, deasphalted oils, residues (hydrotreated or not), as well as by-products from other processes such as extracts, paraffinic slack waxes, distillates from visbreaking and coking, residues from hydrocracking, converted in mixtures with the main feedstock. 

Hydrocracking is the preeminent process for making high quality kerosene and diesel oil (Figure 10.10). 

In two stages with recycle to the second stage, the conversion per pass is approximately 50 wt. % and the selectivity to middle distillates is maximal 75 to 80 wt. %. However, the investment is clearly higher and is justified only when feedstocks are difficult to convert and that their content in nitrogen is high. Figure 10.11 represents two variants of the hydrocracking process. 

The hydrocracking process is characterized by a very low gas production and a low LPG yield especially when operated for maximum distillates. Byproducts in this operating mode are ... 

Typical feedstock composition, yields and product properties for a hydrocracking unit (to be continued). 

This form of limited-conversion hydrocracking is a process that selectively prepares high quality residues for the special manufacture of base oils of high viscosity index or treating residues having low BMCl for the conversion of heavy fractions to ethylene, propylene, butadiene and aromatics. 

Mild hydrocracking prepares the feedstock for catalytic cracking or for the conventional lubricant production scheme. 

Table 10.18 presents some useful data on the mild hydrocracking process and resulting products. 

Typical Feedstocks composition, performance and product properties from mild hydrocracking. I... 

Hydrocracking is a major process for the production of diesel motor fuel catalytic cracking is its counterpart for the gasoline production. 

The question then lies in the selection of more appropriate feedstocks for these two processes. The cost of hydrocracking leads to selecting feedstocks that are the easiest to convert as for catalytic cracking, its flexibility and extensive capabilities lead to selection of heavier feedstocks. 

Hennico, A., A. Billon, P.-H. Bigeard and J.-P. Peries (1993), IFP s new flexible hydrocracking process combines maximum conversion with production of high viscosity, high VI lube stocks . Rev. Inst. Fran. du Petrole, Vol. 48, No. 2, p. 127. 

Maier, C.E., P.-H. Bigeard, A. Billon and P. Dufresne (1988), Boost middle distillate yield and quality with a new generation of hydrocracking catalyst . NPRA paper No. AM-88-76, Annual meeting, San Antonio, TX. 

Processing heavy oils and bitumens represents a challenge for the current refinery processes, because heavy oils and bitumens poison the metal catalysts used m the refineries. In our research at the Loker Institute, we found the use of superacid catalysts, which are less sensitive to heavy oils, an attractive solution to their processing, particularly hydrocracking. 

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