Hydrogen-selective membrane reactor modelling

Mathematical modelling of membrane reactors overview of strategies and applications for the modelling of a hydrogen-selective membrane reactor... 

Marin, P., Patino, Y., Diez, F. V., Ordonez, S. (2012). Modelling of hydrogen perm-selective membrane reactors for catalytic methane steam reforming. International Journal of Hydrogen Energy, 37, 18433—18445. 

Develop a mathematical model for the novel water-gas-shift (WGS) membrane reactor with a carbon dioxide (C02)-selective membrane to elucidate the effects of system parameters on the reactor and to show the feasibility of achieving hydrogen (H2) enhancement via CO2 removal and carbon monoxide (CO) reduction to 10 parts per million (ppm) or lower from the modeling study. 

In modeling membrane reactors, a proper definition of membrane performance in terms of hydrogen flux is crucial. In fact, hydrogen permeation through selective membranes is a leading phenomenon for membrane reactors, and errors in assessing membrane behavior would lead to unreliable results. 

A one-dimensional nonisothermal model has been developed to predict the performance of the novel C02-selective WGS membrane reactor. The modeling results have shown that H2 enhancement and CO reduction to < 10 ppm via CO2 removal are achievable. Results from WGS membrane reactor experiments have shown carbon monoxide reduction to 10 ppm as well as significant hydrogen enhancement via CO2 removal. The data have been in good agreement with modeling prediction. 

Key words membrane reactors, reactor modelling, selective membrane, natural gas steam reforming, hydrogen production, Pd-based membrane. 

In the present chapter, only the IMR shown in Fig. 12.1 is modelled. The SMR modelling is simply composed of the series of a packed bed reactor model (equations described in Section 12.2.2) followed by a membrane separation unit, where only the hydrogen stream permeated through the selective membrane (Equation [12.8]) has to be evaluated. 

Catalytic bed reactors are usually in turbulent conditions, making the ID model absolutely reliable for a sufficiently deep assessment of reactor performance. On the other hand, the 2D models add information on radial temperature and concentration profiles and, in some cases, are necessary for reactor design. Particularly in membrane reactors, there is the problem of membrane overheating, for example the hydrogen-selective Pd-based dense membrane, which can be integrated in many hydrogen production processes (Dittmeyer et al, 2001 Howard et al, 2004 Peachey, et al. 1996 ... 

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