In partnership with Arol Energy, a new methanization-based biogas purification technology has been developed to extract methane (CH4) and inject it into the natural gas network. The process uses an amine solvent developed by IFPEN for capturing CO2 in biogas and demonstrates a superior energy efficiency to conventional membrane solutions.
The development was supported by knowledge acquired in the field of natural gas treatment(1) and CO2 capture, transposed to biogasa and incorporating
its specific characteristics(2). The process thus produces a gas containing 97.5 vol% CH4, meeting the specifications of distribution networks. To achieve this,
a calculation tool was developed to simulate the absorption column, integrating the equilibrium models, physicochemical properties, mass transfer correlations and reaction mechanisms associated with the new solvent, with all the data having been derived from small-scale experiments.
In addition, to improve the absorber design with these data, an original approach was chosen to model the reaction transfer, making it possible to separate the diffusion and reaction phenomena. This consisted in discretizing the equations within the liquid film, close to the interface with the gas, where all the mass transfer phenomena are meant to occur.
On the industrial demonstration unit, an advanced energy integrationb resulted in the proposal of an innovative and competitive process in terms of converted biogas rates, with the biomethane yield of the unit increasing from 69% to 83%(3).
a - Available at atmospheric pressure; composition 50 vol% CO2 - 50 vol% CH4
b - Global approach, on a process or plant scale, with a view to optimized energy use
(1) M. Meyer, L. Hegely, P. Alix, J. Roesler, D. Rouzineau, AIChE Journal, Vol. 63, No 8, 2017, pp. 3246-3275.
(2) C. Peregrina, E. Flottes, P. Collet, L. Raynal, S. Capela, H. Pierre, A. Favre, Applied Energy, Vol. 192, 15 April, 2017, pp. 282-295.
(3) J. Grandjean, A. Wender, K. Lettat, M. Dehlinger, J. Roesler, S. Gonnard, V. Carlier, Poster Presentation, 69th LRGCC, 2019.