Syngas Production and Combustion Applications

Background for Selection of Materials for Syngas Production and Combustion Applications 

Combustion applications, such as in boilers or process heaters, have somewhat different requirements relative to syngas production. The first is that the fuel utilized needs to be fuUy oxidized to CO2 and H2O rather than partially oxidized to CO and H2. This implies that at the exhaust end of the reactor there is no longer a very large oxygen partial pressure gradient. Typical oxygen partial pressure of a 

CO2 and H2O gas mixture present in an exhaust stream is about 0.02 bar, due to the presence of about 2% oxygen. The excess oxygen is present to ensure that there are no uncombusted hydrocarbons or CO. Another major difference is that a high fuel pressure is not required because the products of the combustion are not collected for further use. Tables 6.5 and 6.6 summarize the materials proper- 

It should be noted that the chemical expansion is absolute. Therefore, the desired chemical expansion per unit of partial pressure needs to be much less than in oxygen separation. 

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Rich catalytic combustion will offer wide opportunities with respect to most of the above issues, including flexible integration in different machines, low-temperature ignition ability, tolerance to fuel concentration and temperature non-uniformities and fuel flexibility. Further, the production of syngas in short contact time catalytic reactors could be exploited in several energy-related applications such as fuel cell and oxy-fuel combustion. 

Yet another approach to initiate a CPO reaction is by the use of spark ignition. This technique uses an electric spark situated slightly upstream of the catalyst to ignite a stoichiometric mixture of methane and air for combustion. This feed composition is then altered to the desired composition. This technique has been used for rapid-start application and has been reported to achieve production of syngas in -5 s.58... 

As outlined above, biomass feedstock can also be employed for the production of syngas and, thus, methanol produced from biomass-derived syngas and fuels obtained through processing of biomass-based methanol can be considered as typical biofuels. Blends with petrol containing up to 20% of methanol can be used in combustion engines without elaborate modifications. However, the comparatively low energy density and safety concerns have limited so far broad applications of methanol as fuel. Another option is the use... 

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