Novel Adsorption-Reaction Process for Biomethane Purification/Production and Renewable Energy Storage

• Type: Article in International Scientific Journal
• Date: 2022

Authors

Martins, JA (Author) Other; Miguel, CV (Author) Other; Rodrigues, AE (Author) Other; Luis Madeira (Author) FEUP

Journal

The Journal is awaiting validation by the Administrative Services.

Title: ACS SUSTAINABLE CHEMISTRY & ENGINEERING

Vol. 10

Pages: 7833-7851

ISSN: 2168-0485

Indexing

ISI Web of Knowledge - 0 Citations

Scopus

Associated Projects

HyGreen&LowEmissions - HyGreen&LowEmissions - Tackling Climate Change Impacts: the role of Green Hydrogen production, storage and use, together with low emissions energy systems

Other information

Authenticus ID: P-00W-THH

DOI: 10.1021/acssuschemeng.1c06844

Abstract (EN): This work proposes an innovative method for the simultaneous upgrading of biogas streams and valorization of the separated CO2, through its conversion to renewable methane. To this end, two sorptive reactors were filled with a layered bed containing a CO2 sorbent (K-promoted hydrotalcite) and a methanation catalyst (Ru/Al2O3). The continuous cyclic operation of the parallel sorptive reactors was carried out by alternately feeding a biogas stream (CO2/CH4 mixture) or H-2. The CO2/CH4 mixture is fed to the sorptive reactor during the sorption stage, with CO2 being captured by the sorbent and CH4 exiting as a purified stream (i.e., as biomethane). During the reactive regeneration stage, the inlet stream is switched to pure H-2, which reacts with the previously captured CO2 at the methanation catalyst active sites thus producing additional methane. For continuous operation, the two sorptive reactors were operated 180 degrees out of phase and cyclic steady-state could be reached after ca. five cycles. The performance of the cyclic sorptive-reactive unit was assessed through a parametric study to evaluate the influence of different operating conditions, namely, the inlet flow rate and CO2 content during the sorption stage, the hydrogen inlet flow rate during the reactive regeneration stage, the stage duration, and temperature. The inclusion of an inert purge after the reactive regeneration stage was also tested. The performance of the unit was compared to the case of direct hydrogenation of biogas, and conclusions were drawn regarding future optimization, with special attention being given to CH4 productivity and purity. During the parametric study, a compromise between these process indicators, i.e., a productivity of 1.63 mol(CH4) kg(cat)(-1) h(-1) with 70.3% of CH4 purity, was obtained at 350 degrees C. However, biomethane purities above 80% were easily achieved, though at the expense of methane productivities.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 19