Estudo da separação de misturas CO2/CH4 a baixas pressões empregando processo de adsorção cíclica com modulação de pressão

Abstract

The greenhouse gas emission from burning of fossil fuels can cause catastrophic consequences for the planet environment. Since the establishment of the Kyoto protocol, many countries have been looking for alternative energy sources. In this way, biogas stands out as an important alternative of energy source. However, biogas has only 60% of methane and for this reason yours use as car fuel or transportation to majors cities is not viable. In the last few years considerable efforts in research are undertaken in order to develop new techniques to upgrade biogas in biomethane. Adsorption processes such as pressure swing adsorption (PSA) have a great potential for this purpose. Thus, the main objective of this work was to analyze the CO2 removal from biogas using pressure swing adsorption techniques. Adsorption equilibrium and diffusion of single components were used to predict the behavior of the binary system in fixed bed and in PSA process by mathematical modeling. Experimental and modeling data were obtained to identify the effects of different steps on process performance. The mathematical model was able to predict the behaviors of breakthrough curves and the PSA process from equilibrium and kinetic data. The experimental and model results showed that the PSA process with carbon molecular sieves can get biomethane with a purity greater than 97%. These results also showed that is possible to reach high recovery levels with low cost at small PSA units.