Simultaneous Steam Reforming of Tar and Steam Gasification of Char from the Pyrolysis of Potassium-Loaded Woody Biomass

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• 作者：Tsukasa Sueyasu ; Tomoyuki Oike ; Aska Mori ; Shinji Kudo ; Koyo Norinaga ; Jun-ichiro Hayashi
• 刊名：Energy & Fuels
• 出版年：2012
• 出版时间：January 19, 2012
• 年：2012
• 卷：26
• 期：1
• 页码：199-208
• 全文大小：1107K
• 年卷期：v.26,no.1(January 19, 2012)
• ISSN：1520-5029

文摘

This paper proposes a two-stage conversion of biomass into gas, which consists of pyrolysis at 500鈥?00 掳C and steam reforming/gasification at 600鈥?00 掳C, and has a special feature of recycling of the potassium (K) catalyst. The proposed process was simulated experimentally employing K-loaded cedar as the feedstock and char from its pyrolysis as the catalyst for tar reforming. Tar from the pyrolysis was reformed over the char in a sequence of carbon deposition onto the pore surface and K-catalyzed steam gasification of the deposit, while K-catalyzed char gasification created active pores simultaneously. At the steam/carbon molar ratio of 0.55鈥?.10, the catalysis of K simultaneously realized the concentration of heavy tar (boiling point temperature > 336 掳C) in the product gas as low as 20 mg m³_N dry and progress of the char gasification as fast as that of char formation by the pyrolysis. The concentration of hydrogen in the product gas exceeded 50 vol % dry. A portion of K was released from the pyrolyzing cedar, fully captured by the char bed of the reformer, and involved in the steam reforming and gasification. A major portion of K retained in/on the spent char was extracted with water. The resulting aqueous solution of K was ready to be used as spray for K loading on the feedstock.