No abstract

Non-oxidative methane dehydroaromatization (MDA:6CH 4 ↔ C 6 H 6 + 9H 2 ) using shapeselective Mo/zeolite catalysts is a technology to exploit stranded natural gas reserves by direct conversion into transportable liquids. The reaction, however, faces two major issues: the onepass conversion/yield is limited by thermodynamics, and the catalyst deactivates fast due to the kinetically-favored formation of coke. Here we show that integration of an electrochemical BaZrO 3 -based membrane exhibiting both proton and oxide ion conductivity into an MDA reactor enables high aromatic yields and outstanding catalyst stability. These effects originate from the simultaneous extraction of hydrogen and distributed injection of oxide ions along the reactor length. Further, we demonstrate that the electrochemical co-ionic membrane reactor enables high carbon efficiencies (up to 80%) significantly improving the techno-economic process viability, and sets the ground for its commercial deployment. One Sentence Summary:The integration of a co-ionic membrane in a MDA reactor remarkably enhances aromatics yield and catalyst lifetime. Main text:

a b s t r a c tOxygen transport membranes made of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−ı (BSCF) were manufactured by tape casting and co-firing. The disk-shaped membranes consisted of a top gastight layer (70 m thick) and a porous substrate (830 m thick) with 34% open porosity. The variation of the permeation operation conditions allowed (i) the identification of the different limitations steps in the permeation process, i.e., bulk oxygen ion diffusion, catalytic surface exchange and gas phase diffusion in the membrane compartments and porous substrate, and (ii) the ultimate optimization of the oxygen flux. The variables considered in the systematic permeation study included the inlet gas flow rate of the sweep and air feed, the temperature and the nature of the oxygen feed gas (air or pure oxygen). Moreover, the influence of the deposition of a catalytic activation layer (17 m thick) made of BSCF on top of the thin gastight layer was investigated. As a result of this parametric study, unpreceded oxygen flux values were achieved, i.e., a maximum flux of 67.7 ml(STP) min −1 cm −2 was obtained at 1000 • C using pure oxygen as the feed and argon as the sweep, while a flux of 12.2 ml(STP) min −1 cm −2 at 1000 • C was obtained when air was used as the feed.