Olefinic hydrocarbons process valuables

Diffusive and convective transport processes introduce flexibility in the design of catalyst pellets and in the control of FT synthesis selectivity. Transport restrictions lead to the observed effects of pellet size, site density, bed residence time, and hydrocarbon chain size on chain growth probability and olefin content. The restricted removal of reactive olefins also allows the introduction of other intrapellet catalytic functions that convert olefins to other valuable products by exploiting high intrapellet olefin fugacities. Our proposed model also describes the catalytic behavior of more complex Fe-... 

The fundamental advantage of the use of fluidized catalysts for the highly exothermic hydrocarbon synthesis consists of a radical solution of the crucial heat transfer problem, which limited the yield per space and time in the case of fixed catalyst beds. The fluidized system presents the possibility of going to higher synthesis temperatures which means higher conversions with cheaper catalysts and more efficient heat recovery. This can be done without producing excessive amounts of carbon or methane. The yields of valuable olefinic hydrocarbons are very high in comparison with other hydrocarbon synthesis processes. 

The fully developed petrochemical refinery as modeled in Cases 06 and 07 represents a complete melding of the fuels refinery with olefins-aromatics processing where the efficient scale of the fuels operation is retained while the chemical units provide the best possible end use for the lower valued hydrocarbon streams. At the same time they return certain products whose most valuable use is as components of the gasoline pool. 

The aromatic hydrocarbons are used mainly as solvents and as feedstock chemicals for chemical processes that produce other valuable chemicals. With regard to cyclical hydrocarbons, the aromatic hydrocarbons are the only compounds discussed. These compounds all have the six-carbon benzene ring as a base, but there are also three-, four-, five-, and seven-carbon rings. These materials will be considered as we examine their occurrence as hazardous materials. After the alkanes, the aromatics are the next most common chemicals shipped and used in commerce. The short-chain olefins (alkenes) such as ethylene and propylene may be shipped in larger quantities because of their use as monomers, but for sheer numbers of different compounds, the aromatics will surpass even the alkanes in number, although not in volume. 

As an example of low-temperature catalytic reactions, hydrogenation of unsaturated hydrocarbons is the most important industrial application. Chemical industrial needs are mainly for unsaturated hydrocarbons, which have reactivities that enable polymer or petrochemical product development. All the processes developed for the production of olefins, diolefins, and aromatics give a mixture of unsaturated hydrocarbons, which are not valuable as such further hydrogenations are necessary to obtain usable products for refining and chemical industry. Sulfur is generally considered to be a poison of hydrogenation catalysts. But in the case of hydrodehydrogenation reactions, this compound can also be used as a modifier of selectivity or even, in some cases, as an activator. 

Ruhrchemie-Lurgi—recycle experiments. The production of synthetic hydrocarbons with a high content of olefins (mono-olefins) is desirable in many cases. The olefins increase the octane number of the gasoline and can be used as valuable raw material for many processes (polymer gasoline, lubricating oils, oxo-synthesis, etc.). 

Fossil resources, which include oil, natural gas, and coal, are the major sources of chemical products impacting our modem lives. Hydrocarbons, the principal components of fossil resources, can be transformed through a number of refining processes to more valuable products. One of these processes is called cracking, in which the long carbon chains are cracked (broken down) into smaller and more useful fractions. After these fractions are sorted out, they become the building blocks of the petrochemical industry such as olefins (ethylene, propylene, and butadiene) and aromatics (benzene, toluene, and xylenes). These new hydrocarbon products are then transformed into the final consumer products. Table 1.1 gives examples of some end products made from hydrocarbons. 

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