Desenvolvimento de um sistema de purificação de biogás do aterro sanitário de Palmas/TO empregando um lavador de gás contendo solução de Ca(OH)2

Abstract

The concentration of carbon dioxide (CO2) and methane (CH4), the main greenhouse gases, in the atmosphere has increased with the intensification of human activities. Landfills produce large amounts of gases, called biogas, which are composed of approximately 30 to 45% CO2 and 55 to 70% CH4. CH4, due to its high calorific value, 9100 kcal/m³, can be used for energy use as a sustainable and renewable alternative. In this sense, the present work sought to evaluate the removal of CO2 and, therefore, the increase in the concentration of CH4, of biogas from the landfill of urban solid waste in the city of Palmas, Tocantins, using a low-cost prototype of a gas scrubber. , following an absorption column model, using distilled water added calcium dioxide Ca(OH)2 at 0.1 mol/L, 0.15 mol/L and 0.2 mol/L in the chemical absorption of CO2 and a variation of solution between 281 to 608 L/h. To achieve the objectives of this research, the following methodological steps were developed: (a) flow measurement, (b) collection and analysis of the biogas sample, (c) making the project prototype and (d) experimental tests. A daily biogas flow of 4m³ was measured. The results obtained through the experiment of this research demonstrated to reach methane concentration values ranging from 71 to 86%. The highest value of methane concentration was using 0.20 mol/L for the concentration of the absorber solution and 281 and 608 L/h for the variation of the flow rates of the solution. Thus, it was noticed that to reach higher values of methane concentration it is not dependent on the solution flow, but on the concentration of the absorber solution. Furthermore, reaching a methane concentration of 86%, a calorific value of 31,401 kJ/m3 was achieved.