Catalytic industrial operation

Write the equations describing a simple version of the petroleum industry s important catalytic cracking operation. There are two vessels as shown in Fig. P3.13. Component A is fed to the reactor where it reacts to form product B while depos-... 

It is well known, even from old literature data (ref. 1) that the presence of metal promotors like molybdenum and chromium in Raney-nickel catalysts increases their activity in hydrogenation reactions. Recently Court et al (ref. 2) reported that Mo, Or and Fe-promoted Raney-nickel catalysts are more active for glucose hydrogenation than unpromoted catalysts. However the effects of metal promotors on the catalytic activity after repeated recycling of the catalyst have not been studied so far. Indeed, catalysts used in industrial operation are recycled many times, stability is then an essential criterion for their selection. From a more fundamental standpoint, the various causes of Raney-nickel deactivation have not been established. This work was intended to address two essential questions pertinent to the stability of Raney-nickel in glucose hydrogenation namely what are the respective activity losses experienced by unpromoted or by molybdenum, chromium and iron-promoted catalysts after recycling and what are the causes for their deactivation ... 

An initial hierarchy of required qualities arises out of the detailed analysis of the chemical transformation plus the data from exploratory tests to select the catalytic species. This hierarchy depends on general laws of kinetics and chemical engineering, as well as observations of industrial operations that are more or less analogous. The steps of its articulation are as follows ... 

Producing H2 from hydrocarbons such as natural gas is currently practiced in the chemical industry 25-28 under steady-state conditions with carefully controlled catalytic unit operations. The overall process is as shown in Fig. 7.13. 

Fig. 5.1. Spent sulfuric acid regeneration flowsheet. H2S04(f) in the contaminated spent acid is decomposed to S02(g), 02(g) and H20(g) in a mildly oxidizing, 1300 K fuel fired furnace. The furnace offgas (6-14 volume% S02, 2 volume% 02, remainder N2, H20, C02) is cooled, cleaned and dried. It is then sent to catalytic S02 + Vi02 —> S03 oxidation and H2S04 making, Eqn. (1.2). Air is added just before dehydration (top right) to provide 02 for catalytic S02 oxidation. Molten sulfur is often burnt as fuel in the decomposition furnace. It provides heat for H2S04 decomposition and S02 for additional H2S04 production. Tables 5.2 and 5.3 give details of industrial operations.

Fluidized catalytic reactions have been industrially operated in the fluid bed conditions, but most of the research has been carried out for the teeter bed. Several studies of fluidized catalytic reaction are listed in Table VI, which are of interest in considering transport phenomena in fluidized catalyst beds. 

Formally, ammonia synthesis is closely related to Fischer-Tropsch synthesis. Industrial operation involves the use of an iron catalyst promoted with calcium and potassium oxides. However, the reason we consider this process here is not directly in connection with alkali promotion of the catalyst. We are concerned with a remarkable achievement reported by Yiokari et al. [15], who use a ton-conducting electrolyte to achieve electrochemical promotion of a fully promoted ammonia synthesis catalyst operated at elevated pressure. Specifically, they make use of a fully promoted industrial catalyst that was interfaced with the proton conductor CaIno.iZro.903-a operated at 700K and 50 bar in a multipellet configuration. It was shown that under EP the catalytic rate could be increased by a factor of 13 when... 

The operating conditions for catalytic hydrotreating depend on the particular heavy end and the severity of the transformation required. Temperatures of the order of 375-430 C and pressure in the range 500-2000 psig are not uncommon. Recycle of hydrogen is a normal feature of industrial operations. 

The objectives of the catalytic reforming of naphtha are to increase the naphtha octane number (petroleum refination) or to produce aromatic hydrocarbons (petrochemistry). Bifunctional catalysts that promote hydrocarbon dehydrogenation, isomerization, cracking and dehydrocyclization are used to accomplish such purposes. Together with these reactions, a carbon deposition which deactivates the catalyst takes place. This deactivation limits the industrial operation to a time which depends on the operational conditions. As this time may be very long, to study catalyst stability in laboratory, accelerated deactivation tests are required. The knowledge of the influence of operational conditions on coke deposition and on its nature, may help in the efforts to avoid its formation. 

Carbenium ions are very reactive, isomerizing readily. They can also react with olefins large carbenium ions undergo B- fission, which is the basis of catalytic cracking, currently the largest scale industrial operation of the world petroleum industry. By virtue of the hydride transfer reaction an infinite number of alkane molecules can temporarily be in the active state of the carbenium ion and, for instance, isomerize, as illustrated in scheme 3. 

The oxidation of SO2 by atmospheric O2 (equation 15.90) is very slow, but is catalysed by V2O5 (see Section 26.7). This is the first step in the Contact process for the manufacture of sulfuric acid operating conditions are crucial since equilibrium 15.90 shifts further towards the left-hand side as the temperature is raised, although the yield can be increased somewhat by use of high pressures of air. In practice, the industrial catalytic process operates at 750K and achieves conversion factors >98%. 

Thermal dehydrochlorination of 1,1-dichloroethane at about 820 K is generally used for the production of vinylchloride. However, the process suffers from heavy coke deposition on the reactor walls, and catalytic reactions operating at lower temperatures were investigated in industry. Carbons were found to catalyze the dehydrochlorination (DHC) of alkyl chlorides to the corresponding alkenes. This reaction had been studied in 1933 for its suitability in the production of vinyl chloride. A list of early patents is given in ref. 170. Formation of 1-butene from... 

At isothermal conditions, the catalytic performance of a mixture of regenerated and coked catalyst can be predicted from the performance of a physical mixture. In industrial operation, the use of such mixtures changes local temperatures and associated reactions without affecting the overall heat balance of the FCC unit. As a result, the overall performance of the process can be largely affected. 

Clearly catalytic systems operating under neutral conditions and moderate temperatures and pressures are desirable both from an environmental and economic viewpoint. A new generation of supported reagents that will efficiently promote aerobic oxidation has been developed [26]. They can be used on an industrial scale in place of traditional oxidants, without the production of effluent or byproducts, and have the great advantage of being genuinely catalytic. An example where these catalysts may be effectively utilised is in the production of benzophenones. The... 

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