In this paper, the enrichment of methane by membrane technology was studied by employing (i) a model as well as (ii) a real biogas mixture produced on a laboratory-scale. Thereafter, the endurance of the process was tested at an existing biogas plant. The commercial gas separation module under investigation contained hollow fiber membranes with a polyimide selective layer. During the measurements, the effect of critical factors (including the permeate-to-feed pressure ratio and the splitting factor) was sought in terms of the (i) CH4 content on the retentate-side and (ii) CH4 recovery, which are important measures of biogas upgrading efficiency. The results indicated that a retentate with 93.8 vol% of CH4 – almost biomethane (>95 vol% of CH4) quality – could be obtained using the model gas (consisting of 80 vol% of CH4 and 20 vol% of CO2) along with 77.4% CH4 recovery in the single-stage permeation system. However, in the case of the real biogas mixture, ascribed primarily to inappropriate N2/CH4 separation, the peak methane concentration noted was only 80.7 vol% with a corresponding 76% CH4 recovery. Besides, longer-term experiments revealed the adequate time-stability of membrane purification, suggesting such a process is feasible under industrial conditions for the improvement of biogas quality.
Bibliographical noteFunding Information:
The authors would like to express their gratitude for the financial support provided by the Széchenyi 2020 Programme under the project EFOP-3.6.1-16-2016-00015 , and by the Excellence of Strategic R + D Workshops under the project GINOP-2.3.2–15 (which encompasses the development of modular, mobile water treatment systems and wastewater treatment technologies based at the University of Pannonia to enhance growing dynamic exportation from Hungary between 2016 and 2020). The János Bolyai Research Scholarship of the Hungarian Academy of Sciences is duly acknowledged for the support. This work was supported by the Korea Research Fellowship Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (Grant No: 2016H1D3A1908953 ).This work was supported by the New & Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20173010092470 ).
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Environmental Science(all)
- Strategy and Management
- Industrial and Manufacturing Engineering