Hydrocracking Cracking

Catalysis. As of mid-1995, zeoHte-based catalysts are employed in catalytic cracking, hydrocracking, isomerization of paraffins and substituted aromatics, disproportionation and alkylation of aromatics, dewaxing of distillate fuels and lube basestocks, and in a process for converting methanol to hydrocarbons (54). 

Naphtha is also obtained from other refinery processing units such as catalytic cracking, hydrocracking, and coking units. The composition of naphtha, which varies appreciably, depends mainly on the cmde type and whether it is obtained from atmospheric distillation or other processing units. 

Catalytic conversion processes include naphtha catalytic reforming, catalytic cracking, hydrocracking, hydrodealkylation, isomerization, alkylation, and polymerization. In these processes, one or more catalyst is used. A common factor among these processes is that most of the reactions are initiated hy an acid-type catalyst that promotes carhonium ion formation. 

Since ITQ-4/SSZ-42/MCM-58 have been prepared as aluminosilicates with Si/Al ratios of 20 to °°, which possess Brpnsted sites, there is potential for acid catalysis. Some preliminary accounts of catalytic cracking, hydrocracking, dewaxing, alkylation, hydroisomerization, and reforming reactions have been reported (47, 62-64). 

Like catalytic cracking, hydrocracking processes generate toxic metal compounds, many of which are present in spent catalyst sludge and catalyst fines generated from catalytic cracking and hydrocracking. These include metals such as nickel, cobalt, and molybdenum. 

An example of how feedstock composition can influence the variation in product distribution and quality comes from application of the ABC (asphaltene bottoms cracking) hydrocracking process to different feedstocks (Tables 6-18, 6-19, 6-20, and 6-21) (Takeuchi et al., 1986 Komatsu et al., 1986). A further example of variations in product distributions from different feedstocks comes from the Mild Resid Hydrocracking (MRH) process (Table 6-22 Figures 6-14 and 6-15) (Sadhukhan et al., 1986). In addition, different processes will produce variations in the product slate from any one particular feedstock (Figure 6-14) and the feedstock recycle option adds another dimension to variations in product slate (Tables 6-23 and 6-24) (Munoz et al., 1986). 

The deactivation of catalysts, especially zeolites, during cracking, hydrocracking, methanol conversion, etc, is one of the major technological and economic problems of the chemical industry (1). The interest of these materials lies not only in their high catalytic activity and selectivity but also in the possibility of regenerating them several times so that their Lifetime" is compatible with the cost of their production. Consequently, it is necessary to understand the manner and the rate of catalyst deactivation as well as the nature of the carbonaceous residues formed, commonly called coke". 

This article is a brief review of the state of the art in the use of Nuclear Magnetic Resonance for studpng deactivation of zeolite based catalysts which occurs during cracking, hydrocracking, reforming and isomerization reactions. 

The liquid product obtained from thermal cracking can be either catalytically cracked/ hydrocracked or co-processed with a refinery feed. Since the catalytic cracking of oil derived from MWP is more or less problematic, any cracking catalyst can be applied to oil derived from pyrolysis of plastics. But the yield and the quality of gasohne obtained from cracking step vary with the type of catalyst and the properties of the pyrolytic oil derivated from waste plastics. 

All around the world there exists an installed capacity to process residue utilizing solvent deasphalting as a carbon rejection technology followed by hydrotreatment of the deasphalted oil (DAO) or the residual. Severity of the hydrotreating stage depends on the downstream use of the hydrotreated DAO or the residual, which can be used as feedstocks to catalytic cracking/ hydrocracking or as components of low sulfur fuel. 

Catalytic cracking, Hydrocracking, Aromatic alkylation, NOx reduction, Acetylation... 

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