Methane reforming is usually carried out using steam as oxidizing agent but at temperatures of 500 degrees C and higher. I was wondering if there is any other reforming technology to produce syngas at temperatures
Methane molecules are difficult to break.
In steam reformers, catalysts require more than 450°C let say 500 °C.
And upper temperatures are necessary for equilibrium toward hydrogen.
CPOX is not a solution to operate at 300 °C.
To obtain H2 without going above 500 °C you need a membrane H2 separator in your reactor, so a sort palladium membrane. It is a way to displace equilibrium.
Breaking of C-H bond or a specific reaction to break it at low temperature even on a catalyst requires activated unstable species difficult to obtain.
The problem is to break the molecule without making soot by recombination of C-H species and without oxidising H2.
Regards
At 500 C = 932 F the equilibrium constant
(PH2^3)*(PCO)/((PCH4)*(PH2O)) = 0,01 atm^2
at 815 C = 1499 F Keq = 243 atm^2
The reaction CH4+H2O 3H2+ CO is highly enothermic and equilibrium limited.
As a result you need to add lots of energy at high temperature level to efficiently produce H2 or syngas. A membrane quickly removing the H2 can help a little but not enough to make much H2 at temperatures below 500 C.
Thanks for your answers. The problem with steam reforming is that H2O is not an efficient oxidizing agent and requires high temperatures to become active. O2, instead, is a much stronger oxidizing agent and can help activate CH4 at lower temperatures in a more efficient manner. That is why I thought about CPOX. To stay away from thermodynamic limitations other researchers have tried the short contact time approach which requires the use of highly active catalytic materials, producing high conversion and selectivity to syngas.
Actually POX and Autothermal reforming processes that uses the CH4 + O2 CO + H2 + H2O reaction operate commercially at higher temperature than SMR usually around 1000 C or higher. The problem is still equilibrium limited and when you mix CH4 and O2 it gets pretty hot.
All of the same reactions take place CH4+H2O CO + 3H2
CO + H2O H2 + CO2 and CO + CO C+ CO2 and you need high temperatures if you want to make much H2 and/or CO. H2 and CO are actually pretty much equivalent products. The water gas shift reaction CO+ H2O CO2 + H2 lets you turn CO into H2. fairly easily.