Biotechnology World Convention

Biography

Biography: Paula Lobo Accioly

Abstract

Anaerobic decomposition of organic matter generates biogas, a renewable energy source. The primary components of biogas are methane and carbon dioxide at concentrations varying from 40-75% and 15-60% respectively. Biogas enrichment to 95-97% of CH₄ and 1-3% of CO₂ produces biomethane, which is a direct substitute for natural gas. The production of biomethane requires separating CH₄ from CO₂. Among many, pressure swing adsorption (PSA) is a common technology, which captures carbon dioxide by adsorption on a solid surface. Activated carbons (AC) are porous solids adsorbents of low cost, abundant and with a high CO₂ adsorption capacity. In the interest of increasing carbon dioxide load and considering the weak acid characteristic of CO₂, AC was impregnated in sodium and calcium hydroxide solution, separately, named AC1 and AC2, respectively. Saturation curves were obtained from packed bed reactor operating at 1 bar and 24 °C, which allow determining the carbon dioxide capacity for biomethane production. The results revealed that both AC1 and AC2 are capable of separating the mixture CO₂/CH₄ and the amount of carbon dioxide retained by each were 0.49 and 0.32 mmol/g. Activated carbon impregnated with sodium hydroxide has the highest CO₂ adsorption load in comparison with calcium hydroxide. The packed bed reactor, utilizing AC1, has a breakthrough time of approximately 3.6 minutes. From the initial operation of the fixed bed reactor until the breakthrough time, the column delivers an output gas with methane concentration similar to natural gas.