Steam reforming method

The two predominant methods oPmaking synthesis gas are steam reforming and partial oxidation. Both are quite simple. The steam reforming method involves passing methane or naphtha plus steam over a nickel catalyst. The reaction, if methane is the feedstock, is ... 

Like the steam reforming method, this process takes place at severe conditions, high temperatures and pressures, but no catalyst. The reaction is... 

With the allothermal steam reforming method, catalytic cracking takes place in the presence of water vapor. The necessary heat is supplied from external sources. 

The second way to manufacture hydrogen is by partial oxidation. This process starts with oxygen or air. that is mixed with steam and either a natural gas or a liquid hydrocarbon as the fuel. The free oxygen reacts with the fuel to produce CO2 and water vapor. A secondary reaction between the gases will form hydrogen and CO. Both of these reactions are exothermic. However, in the case of liquid feeds, steam will have to be injected into the reactor. Temperature in the reactor will be around 2500°F (1371 °C) and up to 1500 psi. Once the process stream leaves the reactor, it will go to shift converters and purification areas just like the steam reforming method. 

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. 

In this study, we developed microchannel PrOx reactor to control CO outlet concentrations less than 10 ppm from methanol steam reformer for PEMFC applications. The reactor was developed based on our previous studies on methanol steam reformer [5] and the basic technologies on microchaimel reactor including design of microchaimel plate, fabrication process and catalyst coating method were applied to the present PrOx reactor. The fabricated PrOx reactor was tested and evaluated on its CO removal performance. 

The ability of bimetallic systems to enhance various reactions, by increasing the activity, selectivity, or both, has produced a great deal of interest in understanding the different roles and relative importance of ensemble and electronic effects. Deposition of one metal onto the single-crystal face of another provides an advantage by which the electronic and chemical properties of a well-defined bimetallic surface can be correlated with the atomic structure.5 22 23 Besenbacher et al.24 used this method to study steam reforming (the reverse of the CO methanation process) on Ni(l 11) surfaces... 

Today the two most common methods used to produce hydrogen are (1) steam reforming of natural gas, and (2) electrolysis of water. The predominant method for producing synthesis gas is steam reforming of natural gas, although other hydrocarbons can be used as feedstocks. For example, hydrogen can be produced from the biomass reforming process. 

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