Comparison between the “one-step” and “two-step” catalytic pyrolysis of pine bark

• Published in: Journal of analytical and applied pyrolysis 2012-09, Vol.97, p.39-48
• Main Authors: Güngör, Ahmet, Önenç, Sermin, Uçar, Suat, Yanik, Jale
• Format: Article
• Language: English
• Subjects: bark; Bio-oil; biofuels; catalysts; lignin; Pine bark; Pyrolysis; Upgrading
• ISSN: 0165-2370; 1873-250X
• DOI: 10.1016/j.jaap.2012.06.011

► The bio-oil yields from two-step thermal pyrolysis of pine bark were more than that from one-step thermal pyrolysis. ► The catalytic effect on bio-oil yield was pronounced in two step pyrolysis, leading to decrease in the bio-oil yield. ► The ZSM-5 catalyst was the most effective for decreasing in bio-oil yield followed by ReUS-Y and red mud. In this study, one-step and two-step pyrolysis systems were compared in the pyrolysis of pine bark. One-step pyrolysis was performed in a fixed bed reactor with and without catalyst. Two-step pyrolysis was carried out in a dual reactor system over catalyst; the first reactor containing no catalyst whereas the second reactor containing catalyst to upgrade the thermally cracked products. The catalysts used in the pyrolysis systems were ReUS-Y, red mud and ZSM-5. In thermal pyrolysis, the pyrolysis system mainly affected the relative amount of bio-oil. The bio-oil yields obtained from two-step thermal pyrolysis were higher than the yields from one-step thermal pyrolysis. In the catalytic runs, ReUS-Y catalyst slightly decreased the char formation with a consequent increase in aqueous phase yield in the case of one-step pyrolysis. However, the catalysts decreased the bio-oil yield with a consequent increase in the gas yield in the case of two-step pyrolysis. The general compositions of bio-oils obtained from both two pyrolysis systems were affected by using catalysts. In the case of one-step pyrolysis, the formation of water and water soluble compounds were reduced by using ReUS-Y catalyst. In the case of two-step pyrolysis, both ZSM-5 and red mud increased the formation of water soluble compounds while they decreased water formation. In contrast, ReUS-Y decreased the formation of water soluble compounds and increased the amount of pyrolytic lignin compounds in bio-oil. Fuel characteristics of pyrolysis products (gas, bio-oil and char) for both two pyrolysis systems were also investigated comparatively.