The transition toward a "Hydrogen Economy" could ensure significant advantages in terms of energetic efficiency and environmental impact, with reduced production of greenhouse gases. In the near term, considering the actual lack of infrastructure for H2 storage and distribution, equipment operating with FCs fed with H2 or H2-rich gases, produced by reforming of available fossil (Natural Gas, LPG, Diesel, etc..) and renewable (biogas, bioethanol) fuels, represent a valid and interesting alternative to actual energy generation systems. Even if the reforming technologies are mature, especially SR for hydrogen production on a large scale, more efforts are required for process intensification developing compact systems for small-scale distributed hydrogen production (50-1500 kg/day). Central issues of reforming processes for small-scale application are the development of efficient, stable and low-cost catalysts coupled with the realization of compact and lightweight, fuel processor. In this work, the performances of structured catalysts, based on Rh (1.5wt.%), supported on CeO2, coated on cordierite monoliths (400 cpsi, diameter 1 cm, length 1.5 cm) and alumina foams (20, 30, 40 PPI) were investigated and compared under Steam Reforming (SR) and Oxy Stream Reforming (OSR) of methane (CH4), n-dodecane (n-C12H26) and biogas (CH4=60%, CO2=40%). The structured supports were lined with a novel procedure combining the Solution Combustion Synthesis with the Impregnation technique. All prepared catalysts were characterized by XRD, TEM, SEM and chemisorption analyses. Both monolith and foam catalysts have shown comparable characteristics in terms of uniform thin coating (thickness between 20-30 ?m), high mechanical strength (negligible weight loss ? 0.4% on total weight of the sample after ultrasonic treatment); a low-pressure drop of the monolith respect the foam was observed. In general both foam and monolith samples have shown good catalytic performances, also at high flow rates, in terms of high fuel conversion (CH4Methane = 99-90%, CH4biogas = 99-98%, n-C12H26 = 99% for SR process and CH4Methane = 99-98%, CH4biogas = 99-96%, n-C12H26 = 99% for OSR process) and hydrogen concentration (H2methane= 76-74, H2biogas = 64-62%, H2n-C12H26 = 72-70% in dry and nitrogen-free basis for SR process and H2methane = 69-68%, H2biogas = 59-58%, H2n-C12H26 = 64-60%, in dry basis and nitrogen free for OSR process). The obtained results represent a promising advance in the process intensification of fuel reforming technology: high performances at high space velocity, together with relatively low-cost catalysts, involve a more compact, lightweight and less expensive fuel processors.
STRUCTURED CATALYSTS FOR HYDROGEN PRODUCTION BY STEAM AND OXY STEAM REFORMING OF FOSSIL AND RENEWABLE FUELS
Antonio Vita;Cristina Italiano;Massimo Laganà;Lidia Pino
2016
Abstract
The transition toward a "Hydrogen Economy" could ensure significant advantages in terms of energetic efficiency and environmental impact, with reduced production of greenhouse gases. In the near term, considering the actual lack of infrastructure for H2 storage and distribution, equipment operating with FCs fed with H2 or H2-rich gases, produced by reforming of available fossil (Natural Gas, LPG, Diesel, etc..) and renewable (biogas, bioethanol) fuels, represent a valid and interesting alternative to actual energy generation systems. Even if the reforming technologies are mature, especially SR for hydrogen production on a large scale, more efforts are required for process intensification developing compact systems for small-scale distributed hydrogen production (50-1500 kg/day). Central issues of reforming processes for small-scale application are the development of efficient, stable and low-cost catalysts coupled with the realization of compact and lightweight, fuel processor. In this work, the performances of structured catalysts, based on Rh (1.5wt.%), supported on CeO2, coated on cordierite monoliths (400 cpsi, diameter 1 cm, length 1.5 cm) and alumina foams (20, 30, 40 PPI) were investigated and compared under Steam Reforming (SR) and Oxy Stream Reforming (OSR) of methane (CH4), n-dodecane (n-C12H26) and biogas (CH4=60%, CO2=40%). The structured supports were lined with a novel procedure combining the Solution Combustion Synthesis with the Impregnation technique. All prepared catalysts were characterized by XRD, TEM, SEM and chemisorption analyses. Both monolith and foam catalysts have shown comparable characteristics in terms of uniform thin coating (thickness between 20-30 ?m), high mechanical strength (negligible weight loss ? 0.4% on total weight of the sample after ultrasonic treatment); a low-pressure drop of the monolith respect the foam was observed. In general both foam and monolith samples have shown good catalytic performances, also at high flow rates, in terms of high fuel conversion (CH4Methane = 99-90%, CH4biogas = 99-98%, n-C12H26 = 99% for SR process and CH4Methane = 99-98%, CH4biogas = 99-96%, n-C12H26 = 99% for OSR process) and hydrogen concentration (H2methane= 76-74, H2biogas = 64-62%, H2n-C12H26 = 72-70% in dry and nitrogen-free basis for SR process and H2methane = 69-68%, H2biogas = 59-58%, H2n-C12H26 = 64-60%, in dry basis and nitrogen free for OSR process). The obtained results represent a promising advance in the process intensification of fuel reforming technology: high performances at high space velocity, together with relatively low-cost catalysts, involve a more compact, lightweight and less expensive fuel processors.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
