Kinetic Analysis of the Existing Models of Methanol Steam Reforming for Hydrogen Production

Steam Reforming of Methanol (SRM) reaction has been highly developed and
thoroughly studied process. Liwei Pan (2005) stated that it can offer the highest
maximum hydrogen content in the product gas (75%) while maintaining a high
selectivity towards the harmful product carbon dioxide. SRM thus now becomes the
world's new potential technique of producing hydrogen gas by reacting methanol and
steam at certain optimum temperature. Hydrogen gas is now becoming an increasingly
important source of fuel for today which is widely used for the Proton Exchange
Membrane Fuel Cells (PEMFC) and it also used by various industrial processes. As a
result, many researchers have been seriously studying the kinetics of the SRM in order
to investigate the nature of the process and then develop the best way to produce
hydrogen gas through steam reforming technique. This research will attempt to study the
two widely accepted kinetic models of SRM proposed by two authors; Peppley and
Patel & Pant. Both of the authors have proposed two different models pertaining to the
mechanism of the SRM. Since the models are already available, comparison will be
made by taking both models into simulation mode. The Microsoft Excel software will be
used to simulate kinetic models and the concentration profile as well as the kinetic rate
profile will be compared.

In this report, the literature reviews of the various journals are made pertaining to
the steam reforming of methanol in the study of hydrogen production. Matters such as
the reaction path proposed by different authors, the discussion about the newly
developed proton exchanged membrane fuel cell (PEMFC), thermodynamics
consistency, carbon monoxide (CO) formation associated to the steam reforming of
methanol and also the preventive action to minimize CO formation is discussed in detail
in the report. Besides that, the expected results are also shown which are obtained by
different authors through experimental and simulation work.
It is learned from the result of the simulation that the Peppley Model is better if
compared to the Patel-Pant Model. The Peppley Model seems to be more robust. It is
because the model is consistent with the local thermodynamic. The Patel-Pant Model
has got inconsistency in it, though it shows some better characteristics compared to the
one of Peppey such as in the flowrate profile as well as in the least production of the
carbon monoxide gas, CO. However, the Peppley model needs to be modified to make it
a better model. The rate expression need to be further simplified as the one proposed by
Purnarna et. al (2004). Last but not least, the WGS reaction rate expression must be
changed so that it can suit the RWGS trend that is actually happening in the Peppley
Model.