Investigation of the CO2 adsorption capacity of chars produced by pyrolysis of macro-components of digested manure and their blends

Carstensen , Hans-Heinrich
Participation type: 
Comunicación oral
Other authors: 
Isabel Fonts, M. Abián, Noemí Gil-Lalaguna, Javier Ábrego, José-Luis Sánchez
Sardinia, Italy
Isabel Fonts 1,2, M. Abián 1, Noemí Gil-Lalaguna 1, Javier Ábrego 1, José-Luis Sánchez 1, Hans-Heinrich Carstensen 3,4 1 Thermochemical Processes Research Group (GPT), Aragón Institute of Engineering Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain 2 Área de Química y Medio Ambiente, Centro Universitario de la Defensa (CUD) de Zaragoza- Academia General Militar, 50090, Zaragoza, Spain 3 Fundación Agencia Aragonesa para la Investigación y Desarrollo (ARAID), Zaragoza 4 Department of Chemical and Environmental Engineering, Engineering and Architecture School, University of Zaragoza, Spain "INVESTIGATION OF THE CO2 ADSORPTION CAPACITY OF CHARS PRODUCED BY PYROLYSIS OF MACRO-COMPONENTS OF DIGESTED MANURE AND THEIR BLENDS"

Cellulose, lignin, soybean protein and calcium carbonate are used as representative macro compounds for bio-degraded manure. Chars from the pyrolysis of these components and mixtures thereof at 750oC in the ceramic reactor of a thermogravimetric analyzer are tested for their capability to adsorb CO2. Adsorption isotherms are measured at 25oC and the temperature dependence of CO2 adsorption is studied between 25oC and 120oC. The results lead to the following conclusions: First, the chars from cellulose and lignin show quite good CO2 adsorption but the char yields from lignin are more than two times higher. Second, soybean protein pyrolysis produces little char which hardly adsorbs CO2. CaO from CaCO3 calcination only adsorbs CO2 slowly but irreversibly. Third, char production and quality of mixtures can in most cases be rationalized by additive contributions from the pure components, meaning that no positive synergetic effects from the protein or calcium carbonate are observed. Fourth, the adsorption isotherms are in line with Dubinin’s theory of volume filling of micropores (TVFM). Also in agreement with TVMF is the small enthalpy of adsorption deduced from the temperature dependent data. Finally, the char properties obtained with organosolv lignin differ substantially from those with Kraft lignin. Based on the current work, it seems unlikely that manure can be valorized by pyrolyzing it at 750oC to a profitable CO2-adsorbing char.