Isomerization dewaxing

MIDW [Mobil isomerization dewaxing] A petroleum refining process which improves yield and quality by isomerizing and selectively cracking paraffins in waxy oils. The catalyst is a noble metal, supported on a zeolite. Developed by Mobil Corporation from 1991 to 1996. 

Catalytic isomerization dewaxing on the other hand preferentially isomerizes the paraffins, reducing the diesel pour point and cloud point while keeping the high-cetane components in the diesel product. It also favourably decreases the boiling range of the fuel (T95) and produces a higher mid distillate yield. 

Dewaxing catalysts are manufactured by both Akzo Nobel and Mobil. Mobil s Isomerization Dewaxing (MIDW) first commercialized in 1990 uses a Pt-based zeolite catalyst to crack and isomerize n-paraffins to iso-parrafins, thereby converting fuel oil to low-pour-point distillates. 

In shape-selective catalysis, the pore size of the zeoHte is important. For example, the ZSM-5 framework contains 10-membered rings with 0.6-nm pore size. This material is used in xylene isomerization, ethylbenzene synthesis, dewaxing of lubricatius oils and light fuel oil, ie, diesel and jet fuel, and the conversion of methanol to Hquid hydrocarbon fuels (21). 

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). 

Detergent manufacturing Catalytic cracking and hydrocracking Xylene isomerization, benzene alkylation, catalytic cracking, catalyst dewaxing, and methanol conversion. 

Iso-CDW [Isomerization and catalytic dewaxing] A general term for dewaxing processes which include these two processes. Exemplified by Isodewaxing, MSDW. 

Isodewaxing A catalytic dewaxing process developed by Chevron Research Technology. It incorporates catalysts that achieve both wax isomerization and shape-selective cracking. 

Figure 5 schematically illustrates the concepts of reactant shape selectivity. Only linear paraffins that are able to diffuse and are adsorbed inside the pores can undergo a chemical transformation, e.g., acid catalyzed cracking. The property is exploited in some chemical processes, such as the dewaxing of lubes and middle distillates, through the selective cracking or isomerization of the linear paraffin fraction. 

LP mordenite doped with platinum is the catalyst used in the Shell Hysomer process for alkane hydroisomerization this can be linked to the Isosiv separation process whereby -/n-alkanes are separated on LTA zeolite. This link is the basis of the joint Shell/UOP Total Isomerization Process (TIP). Similar catalysts have been employed to hydrocrack (i.e. dewax) diesel fuels. There have also been reports of commercial use of mordenite to catalyze methanol amination with ammonia, to produce dimethylamine. 

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