Platinum reforming

Promoters, usually present in smaU amount, which enhance activity or retard degradation for instance, rhenium slows coking of platinum reforming, and KCl retards vaporization of CuCU in oxy-chlorination for vinyl chloride. 

Powerforming is a version of the platinum reforming process. Basically there are two types of unit semi-regenerative and cyclic. The choice of unit and the exact process conditions used will depend to a large extent on the particular application. However, certain generalizations regarding each of the two types can be made. 

Hydrofining is applied to virgin naphthas mainly in the form of a pretreatment step for the feed to catalytic reformers (Powerforming). Sulfur levels of 5 parts per million (ppm) or less are required to avoid deactivation of the platinum reforming catalyst. 

Sovaforming [Socony Vacuum reforming] A catalytic reforming process, using a platinum catalyst in a fixed bed. Developed by the Socony-Vacuum Oil Company in 1954. Subsequently renamed Platinum Reforming, or PR. 

Platinum loadings, reducing, 19 628 Platinum metals plating, 9 822-823 Platinum oxides, volatilized, 17.T80 Platinum-palladium thermocouple, 24 461 Platinum reforming catalysts, rhenium and, 21 695-696... 

This pore size distribution was shown to provide an optimum pore structure for platinum reforming catalyst activity, selectivity and catalyst life. This catalyst eventually was commercialized and became the famous RD-150 still in use in only slightly modified form. 

Hydroprocessing and special absorption techniques are utilized to remove sulfur and nitrogen from the reformer. If not removed through hydroprocessing, feedstock sulfur will be converted to H2S in the reformer. The H2S will then serve as a poison to the platinum reformer catalyst and diminish the dehydrogenation and dehydrocyclization reactions. When present, H2S can neutralize the acid sites on the catalyst diminishing the ability of the catalyst to promote isomerization, dehydrocyclization, and hydrocracking reactions. 

Metals such as arsenic, copper, and lead are severe reformer catalyst poisons. Only a few parts/billion are needed to poison the platinum reformer catalyst. Water in the feed will promote hydrocracking reactions and lower reformer and produced hydrogen yield. 

Over 30 man-years of effort were involved in developing the model, which is named KINPTR, an acronym for kinetic platinum reforming model. Since its development, KINPTR has had a major impact in Mobil s worldwide operations. It can be accessed by personnel at each of Mobil s locations throughout the world. Input requirements are simple and convenient making it very user friendly. Only feed characteristics, product quality targets, process configuration information, and process conditions are required for input. Output is informative and detailed. Overall and detailed yields, feed and product properties, and reactor performance data are given in the output. 

In general, it has been taken for granted that the disappearance of XRD peaks of an active component in a catalyst is due to the fact that the active component is present in such a small quantity as to evade detection by XRD. For example, in a supported noble metal catalyst, such as a platinum-reforming catalyst, Pt/y-Al203, the metal content, of the order of 0.1%, is too low to be detectable by XRD. However, this is not the case for the catalyst of our present interest. For the catalysts referred to in Fig. 

Reforming. The hydrotreated naphthas were reformed over a conventional platinum reforming catalyst in an attempt to maximize aromatics. The catalyst was Cyanamid AERO PHF-4 (0.3% Pt, 0.6% Cl). The intent was to operate the reformer at constant conditions in order to better compare naphthas. By operating at severe conditions, the expected hydrocracking activity of the catalyst would tend to purify the aromatics by selectively cracking away the paraffins. If the resultant reformate had a suitably high aromatic content, it could be fed directly to a hydrodealkylator. 

Weisz and Prater 28) have pointed out that, while on platinum reforming catalysts alkylcyclohexanes will proceed rapidly to aromatics, the conversion of alkylcyclopentanes to aromatics becomes the key dualfunctional reforming reaction in the neighborhood of 98 (R.O.N. with 3 ml. 

Fig. 18. Correlation between octane number and aromatics content of platinum reformed gasolines, for three different sources of naphtha.

An example of the need for sharpness control might be the benefit of removing dicyclic hydrocarbons boiling at 400° F or above from the catalytic reforming feed, while maintaining naphtha yield. These dicyclics are known to foul platinum reforming catalysts with carbon. 

The MTG plant employs Mobil s fixed bed catalytic process using the Mobil proprietary zeolite catalyst, ZSM-5. The process is very similar to conventional vapour phase catalytic petroleum refinery processes, such as hydro-treating and platinum reforming. 

While the emphasis in this discussion is on the chemistry of aromatics production from the point of view of product distribution and mechanisms, it is necessary to describe the catalyst used briefly. Until about 20 years ago a number of different catalysts were used for catalytic reforming, including vanadium (126), molybdenum (47), cobalt-molybdenum (159), and chromia (3,41,85,100) catalysts. Since the time when platinum reforming catalysts were introduced to the industry (2, 24, 56,... 

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