title: Biogas cleaning and upgrading with natural zeolites from tuffs.
abstract: CO2 adsorption on synthetic zeolites has become a consolidated approach for biogas upgrading to biomethane. As an alternative to synthetic zeolites, tuff waste from building industry was investigated in this study: indeed, this material is available at a low price and contains a high fraction of natural zeolites. A selective adsorption of CO2 and H2S towards CH4 was confirmed, allowing to obtain a high-purity biomethane (CO2 <2 g m(-3), i.e. 0.1%; H2S <1.5 mg m(-3)), suitable for injection in national grids or as vehicle fuel. The loading capacity was found to be 45 g kg(-1) and 40 mg kg(-1), for CO2 and H2S, respectively. Synthetic gas mixtures and real biogas samples were used, and no significant effects due to biogas impurities (e.g. humidity, dust, moisture, etc.) were observed. Thermal and vacuum regenerations were also optimized and confirmed to be possible, without significant variations in efficiency. Hence, natural zeolites from tuffs may successfully be used in a pressure/vacuum swing adsorption process.
authors.affiliation: a Institute of Atmospheric Pollution Research, Italian National Research Council , Monterotondo (RM) , Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Paolini
authors.affiliation: a Institute of Atmospheric Pollution Research, Italian National Research Council , Monterotondo (RM) , Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Petracchini
authors.affiliation: a Institute of Atmospheric Pollution Research, Italian National Research Council , Monterotondo (RM) , Italy.
authors.forename: Ettore
authors.initials: E
authors.lastname: Guerriero
authors.affiliation: a Institute of Atmospheric Pollution Research, Italian National Research Council , Monterotondo (RM) , Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bencini
authors.affiliation: b AZZERO CO2 srl , Roma (RM) , Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Drigo
mesh_terms: D000327:Adsorption; D056804:Biofuels / Q000032:analysis*; D002245:Carbon Dioxide / Q000302:isolation & purification*; D006862:Hydrogen Sulfide / Q000302:isolation & purification*; D008697:Methane / Q000302:isolation & purification*; D011312:Pressure; D014618:Vacuum; D017641:Zeolites / Q000737:chemistry*
chemical_list: D056804:Biofuels; D017641:Zeolites; D002245:Carbon Dioxide; D008697:Methane; D006862:Hydrogen Sulfide
keywords: Biogas; biomethane; hydrogen sulphide; natural zeolites; pressure swing adsorption