Evaluation of Various Membrane Performances inHydrogen Purification

The main aim of this work is the presentation of quantitative analysis of various membranes for hydrogen separation from methanol steam reforming products to produce high purity hydrogen. This study uses a single stage membrane in three different membrane types, namely, silica, polymeric and carbon membranes for separation of a typical methanol steam reforming products stream for cocurrent flow pattern. The modelling results showed that the silica membrane presents noticeable performance to produce high purity hydrogen. In particular, for these membranes, by considering the stage cut, it was found that the hydrogen molar fraction in the permeate side was decreased by increasing the stage cut from 0.15 to 0.65, whereas the carbon monoxide molar fraction increased for all of the membrane types. Moreover, the retentate side pressure effect was positive on the performance of silica, polymeric and carbon membranes. Although, the improvement of silica membrane performance was not considerable for more than a pressure gradient of 4 bar. This analysis indicated that by using single stage silica membrane, 98% hydrogen molar fraction and 0.3% carbon monoxide molar fraction in the permeate side can be achieved for a pressure gradient equal to 4 bar.

Keywords:

Hydrogen separation , Modelling , Silica membrane , Polymeric membrane , Carbon membrane