Steam reforming of hydrocarbons

Industrial. The main means of producing hydrogen industrially are steam reforming of hydrocarbons... 

Figure 8.3.1 is a typical process diagram for tlie production of ammonia by steam reforming. Tlie first step in tlie preparation of tlie synthesis gas is desulfurization of the hydrocarbon feed. Tliis is necessary because sulfur poisons tlie nickel catalyst (albeit reversibly) in tlie reformers, even at very low concentrations. Steam reforming of hydrocarbon feedstock is carried out in tlie priiiiiiry and secondary reformers. 

Figure 4.1. A process for producing hydrogen by steam reforming of hydrocarbons (1) reforming furnace (2,3) purification section, (4) shift converter, (5) pressure swing adsorption.

In the production of hydrogen by the steam reforming of hydrocarbons, the classic water-gas reaction is used to convert CO in the gases leaving the reforming furnace to hydrogen, in a shift converter. 

Indirect employment of hydrocarbons involves a preliminary conversion (e.g., by steam reforming) of hydrocarbons to syngas followed by the reduction of iron oxides with H2 and CO components of the syngas. The following reactions occur during the reduction of... 

Over 90% of all carbon dioxide is made by steam-reforming of hydrocarbons, and much of the time natural gas is the feedstock. It is an important by-product of hydrogen and ammonia manufacture. 

In addition to the direct use of ethanol as a fuel, its use as a source of H2 to be used with high efficiency in fuel cells has been thoroughly investigated. H2 production from ethanol has advantages compared vdth other H2 production techniques, including steam reforming of hydrocarbons and methanol. Unlike hydrocarbons, ethanol is easier to reform and is also free of sulfur, which is a well-known catalyst poison. Furthermore, unlike methanol, ethanol is completely renewable and has lower toxicity. 

Steam reforming of hydrocarbons is one of the oldest and most widely used processes in the chemical industry for producing H2. In this process, hydrocarbons react with steam in the presence of a supported metal catalyst at elevated temperatures to generate primarily H2 and CO (reaction (2)). This... 

The results for the effect of alkali are interesting in connection with the type of catalysts which have been used commercially for the steam reforming of hydrocarbons.2 64 The original commercial materials were carefully... 

Hydrogen is also manufactured industrially by direct electrolysis of H20, HF, and 22% to 25% hydrochloric acid (HC1). However the hydrogen produced by electrolysis only accounts for a small percentage of the total H2 production (see Table 5.7 and Table 5.8). One advantage of electrolysis (compared to steam reforming of hydrocarbons) is that the hydrogen from the electrolysis is very pine (>99 vol %), which eliminates the costly purification steps needed with reforming. 

The steam reforming of hydrocarbons is in principle a reduction of water with the carbon of the organic starting material. In the case ofmethane, / of the hydrogen is supplied by water. This share increases with the higher hydrocarbons. Other reactions that proceed at the same time as the reforming... 

J.R. Rosrup-Nielsen, Activity of Nickel Catalysts for Steam Reforming of Hydrocarbons J. Catal., 31 173-99 (1973). 

The classical way to produce hydrogen is steam reforming of hydrocarbons, mostly methane. The overall steam reforming reaction is given by ... 

Steam reforming of hydrocarbons has become the most widely used process for producing hydrogen. One of the chief problems In the process Is the deposition of coke on the catalyst. To control coke deposition, high steam to hydrocarbon ratios, n, are used. However, excess steam must be recycled and It Is desirable to minimize the magnitude of the recycle stream for economy. Most of the research on this reaction has focused mainly on kinetic and mechanistic considerations of the steam-methane reaction at high values of n to avoid carbon deposition ( L 4). Therefore, the primary objective of this studyis to determine experimentally the minimum value of n for the coke-free operation at various temperatures for a commercial catalyst. 

Dihydrogen is an important industrial chemical, mostly made from the steam reforming of hydrocarbons from petroleum and natural gas. The simplest of these reactions,... 

The length of the induction period is affected by all the same factors which affect the coking rate of nickel catalysts in the steam reforming of hydrocarbons. A high dispersion of nickel, an increase in MgO content in the support or a small additive of a promoter all cause a prolongation of the induction time. 

Technical and Economic Advances in Steam Reforming of Hydrocarbons... 

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