Mathematical modeling of low-pressure H2S adsorption by babassu biochar in fixed bed column. Issue 1 (February 2021)

• Record Type: Journal Article
• Authors: Scheufele, Fabiano Bisinella; da Silva, Eliane Soares; Cazula, Bárbara Bulhões; Marins, Daniel Sena; Sequinel, Rodrigo; Borba, Carlos Eduardo; Patuzzo, Giovani Silvero; Lopez, Thiago Fernando Magrini; Alves, Helton José
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 1(2021)
• Publication Date: 2021-02
• Subjects: Biogas desulfurization -- Adsorption mechanism -- Axial dispersion -- Equilibrium -- Kinetics -- Ergun equation; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.105042
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: The H2 S removal by a microporous babassu-derived biochar (BBC) in fixed bed column under low pressure and temperature conditions was evaluated. For this, a mathematical model was coded to describe equilibrium and mass transfer kinetics in the column. The BBC showed desirable textural properties, namely, elevated external and micropore surface areas (584 m 2 g −1 and 322 m 2 g −1 ) with super- and ultramicropores (7.8 Å and 5.8 Å) favoring the H2 S diffusion. Also, various oxygenated groups provided high affinity for BBC-H2 S system. The mathematical model was able to adequately describe the experimental data and to determine equilibrium ( q max = 20.61 mg g −1 and b = 16.84 L mg −1 ) and kinetic parameters ( k G = 1.404 × 10 −2 to 2.378 × 10 −2 min −1 and D ax = 422.06 cm 2 min −1 ). Laminar flow ( Re p = 16.74) and small pressure drops were identified under the fluid dynamics conditions. Sensitivity analysis evidenced axial dispersion presents a minor effect over the bed performance, however for other flow conditions it should not be neglected. Also, the model showed predictive capacity, hence can support the adsorption systems design and scale-up. Overall, the BBC showed remarkable features for the H2 S adsorption in fixed bed column, especially considering low-pressure and temperatures, since it allows straightforward infrastructure facilities. Graphical Abstract: ga1 Highlights: Biochar presents desirable textural properties/surface chemistry for H2 S removal. H2 S adsorption onto biochar mainly take place on oxygen groups, except for hydroxyl. Phenomenological mathematical modeling was applied to H2 S adsorption in fixed bed. Axial dispersion presents a minor effect under the studied fluid dynamic conditions. LDF model showed predictive capacity hence it can support fixed bed design/scale up.