The hydrogen diffusion membrane may be applied to the upstream surface of a porous or microporous support and {HEAD ~ the methanation catalyst} may be applied to {TAIL ~ the downstream surface} of the porous or microporous support 
applied to
The hydrogen diffusion membrane may be applied to the upstream surface of a porous or microporous support and { HEAD ~ the methanation catalyst } may be applied to { TAIL ~ the downstream surface } of the porous or microporous support
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH