Hydrocrack residuum

Residuum which is less refractory and thus amenable to upgrading in a conventional second-stage hydrocracker... 

Fig. 16. Schematic flow diagram showing solvent deasphalting (SDA) combined with residuum hydrocracking (Howell et al., 1985).

The distinction in Table XX between hydrotreating and hydrocracking processes is frequently misleading when residuum hydroprocessing is being considered. Hydrotreating conventionally has been referred to processes... 

High amounts of asphaltenes and resins require high hydrogen partial pressures and may actually limit the maximum level of hydrodesulfurization, or final traces of sulfur in the residuum may only be eliminated under extremely severe reaction conditions where hydrocracking is the predominant reaction in the process. High asphaltene and resin contents are also responsible for high viscosity (Figure 6-7) which may increase the resistance to mass transfer of the reactants... 

Figure 6-14 Integration of the mild residuum hydrocracking (MRH) process into a refinery.

The ET-II process is a thermal cracking process for the production of distillates and cracked residuum for use as a metallurgical coke and is designed to accommodate feedstocks such as heavy oils, atmospheric residua, and vacuum residua (Kuwahara, 1987). The distillate (referred to in the process as cracked oil) is suitable as a feedstock to hydrocracker and fluid catalytic cracking. The basic technology of the ET-II process is derived from that of the original Eureka process. 

The volatile products from the soaking drum enter the fractionator where the distillates are fractionated into desired product oil streams, including a heavy gas oil fraction. The cracked gas product is compressed and used as refinery fuel gas after sweetening. The cracked oil product after hydrotreating is used as fluid catalytic cracking or hydrocracker feedstock. The residuum is suitable for use as boiler fuel, road asphalt, binder for the coking industry, and as a feedstock for partial oxidation. 

The Demex process is a solvent extraction demetallizing process that separates high metal vacuum residuum into demetallized oil of relatively low metal content and asphaltene of high metal content (Table 8-5) (Houde, 1997). The asphaltene and condensed aromatic contents of the demetallized oil are very low. The demetallized oil is a desirable feedstock for fixed-bed hydrodesulfurization and, in cases where the metals and carbon residues are sufficiently low, is a desirable feedstock for fluid catalytic cracking and hydrocracking units. 

The major goal of hydroconversion is the cracking of residua with desulfurization, metal removal, denitrogenation, and asphaltene conversion. The residuum hydroconversion process offers production of kerosene and gas oil, and production of feedstocks for hydrocracking, fluid catalytic cracking, and petrochemical applications. 

Hydrogen willfully produced for use in U. S. refineries for gas oil desulfurization and residuum hydrocracking and desulfurization probably will increase from about 1.8 billion SCF/D in 1980 to 3.9 billion SCF/D in the year 2000. These figures... 

In recent years, a more severe type of hydrogen treating has been added to refinery processing systems in which heavy distillates (gas oil) and residuum are hydrotreated to remove sulfur and to convert these heavier hydrocarbons to products of lower molecular weight. The addition of "external" hydrogen increases the H/C ratio of the products substantially above that of the feed stocks. The use of these hydrocracking and... 

This source of hydrogen is being effectively utilized with the aid of the cryogenic hydrogen upgrader to recover and purify hydrogen for return to such refinery applications as residuum hydrocracking and hydrodesulfurization. 

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