Alternatives to steam reforming

The catalytic partial oxidation of methane for the production of synthesis gas is an interesting alternative to steam reforming which is currently practiced in industry [1]. Significant research efforts have been exerted worldwide in recent years to develop a viable process based on the partial oxidation route [2-9]. This process would offer many advantages over steam reforming, namely (a) the formation of a suitable H2/CO ratio for use in the Fischer-Tropsch synthesis network, (b) the requirement of less energy input due to its exothermic nature, (c) high activity and selectivity for synthesis gas formation. 

Oxidation reactions are much faster than reforming reactions, suggesting that a single stage process for syngas generation would be a viable alternative to steam reforming. 

The production of hydrogen from methane over zeolite supported metal catalysts can be examined as an alternative to steam reforming because the concomitant aromatization reactions can increase the economic potential of the process. For methane aromatization, Mo/ZSM5 catalysts have been intensively studied since their first report in 1993 (/, 2). In 1997 (3), the promotional effect of ruthenium over Mo/ZSM5 catalysts was reported. Other second metals have also been studied to improve catalyst activity and stability and a review on this topic is available 4). 

The partial oxidation of natural gas has been considered as an alternative to steam reforming for many years. While natural gas partial oxidation was practiced commercially for ammonia manufacture over 30 years ago (ref. 2), it s use for methanol synthesis remains to be demonstrated commercially. Autothermic reforming (ref. 3), and various other improvements, such as low energy distillation (ref. 4), demonstrate that methanol production can be improved in the short term. 

One of the most attractive alternatives to steam reforming for syngas production appears to be the catalytic partial oxidation (CPO) catalysed by supported noble metal [9]. Perovskites incorporating the noble metal in the structure represent a valid alternative to reduce the catalyst unit mass cost. 

As an alternative to steam reforming, methane and other hydrocarbons may be converted to hydrogen for fnel cells via partial oxidation ... 

Alternatives to Steam Reforming Technology. "Direct Conversion. 

Non-catalytic partial oxidation or gasification of hydrocarbons or solid feedstocks are alternatives to steam reforming and autothermal reforming for production of synthesis gas. 

In contrast to steam reforming, gasifieation is a non-catalytic process and is therefore very flexible in its feedstock requirements. At times of high natural gas priees this ability to process cheap feeds ean make gasifieation an attractive alternative. This eapability does, however, require additional eapital, since at the minimum, facilities for removing unwanted components in the feedstock, such as sulfur or ash, must be included. 

As mentioned above in Section 2.3, partial oxidation is an alternative process to steam reforming for producing hydrogen from methane. It is also applicable to a wide range of liquid hydrocarbons that include heavy oils found in low-value refinery residues (refinery bottoms ) and to the gasification of coal see Section 2.7. In general terms, the process may be expressed as ... 

An alternative approach to steam reforming is to add oxygen to the feed and hence gain the necessary heat by internal combustion. It means that the steam formed by the combustion is condensed in the process stream instead of leaving as water vapour in the flue gas from the fired reformer. Hence, the higher heating value of the fuel is recovered in the partial... 

Selecting the naphtha type can be an important processing procedure. For example, a paraffinic-base naphtha is a better feedstock for steam cracking units because paraffins are cracked at relatively lower temperatures than cycloparaffins. Alternately, a naphtha rich in cycloparaffins would be a better feedstock to catalytic reforming units because cyclo-paraffins are easily dehydrogenated to aromatic compounds. Table 2-5 is a typical analysis of naphtha from two crude oil types. 

The steam reforming of natural gas process is the most economic near-term process among the conventional processes. On the other hand, the steam reforming natural gas process consists of reacting methane with steam to produce CO and H2. The CO is further reacted or shifted with steam to form additional hydrogen and CO2. The CO2 is then removed from the gas mixture to produce a clean stream of hydrogen. Normally the CO2 is vented into the atmosphere. For decarbonization, the CO2 must be sequestered[l,2]. The alternative method for hydrogen production with sequestration of carbon is the thermal decomposition of methane. 

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