催化学报 ›› 2023, Vol. 48: 101-116.DOI: 10.1016/S1872-2067(23)64407-9

• 论文 • 上一篇    下一篇

不同固定床位置生物质热解挥发物蒸汽催化重整反应中焦炭的形成和演化

Enara Fernandeza, Laura Santamariaa, Irati Garcíaa, Maider Amutioa, Maite Artetxea, Gartzen Lopeza,b,*(), Javier Bilbaoa, Martin Olazara   

  1. a巴斯克大学化工系, 西班牙
    b巴斯克科学基金会, 西班牙
  • 收稿日期:2022-11-22 接受日期:2023-02-06 出版日期:2023-05-18 发布日期:2023-04-20
  • 通讯作者: * 电子信箱: gartzen.lopez@ehu.es

Elucidating coke formation and evolution in the catalytic steam reforming of biomass pyrolysis volatiles at different fixed bed locations

Enara Fernandeza, Laura Santamariaa, Irati Garcíaa, Maider Amutioa, Maite Artetxea, Gartzen Lopeza,b,*(), Javier Bilbaoa, Martin Olazara   

  1. aDepartment of Chemical Engineering, University of the Basque Country UPV/EHU, P.O. Box 644 - E48080 Bilbao, Spain
    bIKERBASQUE, Basque Foundation for Science, Bilbao, Spain
  • Received:2022-11-22 Accepted:2023-02-06 Online:2023-05-18 Published:2023-04-20
  • Contact: * E-mail: gartzen.lopez@ehu.es (G. Lopez).

摘要:

对生物质热解挥发物蒸汽重整反应过程中催化剂的失活过程和主要机理进行了研究. 在圆锥形喷动床反应器中于500 °C进行生物质热解, 随后在固定床反应器中于600 °C进行重整反应; 同时在不同轴向位置分析了催化剂位置对重整反应器的影响. 采用N2吸附-脱附、X射线衍射、扫描电镜、透射电镜、程序升温氧化、拉曼光谱和傅里叶变换红外光谱对失活样品进行表征. 结果表明, 焦炭沉积是初始催化剂活性衰减的主要原因, 且没有观察到镍位点的烧结或氧化. 随着反应的进行, 沿着重整催化床观察到失活情况, 焦炭沉积于催化剂内, 其性质和组成取决于到达床中每个轴向位置的挥发物组成. 在催化床的入口部分, 焦炭沉积在Ni位点上, 并且具有一定的含氧量. 在更深的轴向床位置, 催化剂与挥发性物质接触, 该挥发性物质的组成已经明显改变, 从而形成具有石墨化程度更高的焦炭, 并且形成更多的缩合聚芳烃化合物. 此外, 沉积在所有失活样品上的焦炭没有呈现任何特定的形态, 这也表明, 无论所处的催化床位置和反应时间, 焦炭均呈现无定形结构.

关键词: 生物质, 热解, 蒸汽重整, 失活, 积碳, 氢气, 生物油

Abstract:

The evolution and the main mechanisms of catalyst deactivation have been assessed throughout continuous operation in the steam reforming of biomass pyrolysis volatiles. Biomass pyrolysis was conducted in a conical spouted bed reactor at 500 °C and the subsequent reforming step in a fixed bed reactor at 600 °C. The influence of catalyst location on the reforming reactor is also analyzed at different axial positions. Deactivated samples have been characterized by N2 adsorption-desorption, XRD, SEM and TEM images, TPO, Raman and FTIR spectroscopies. Coke deposition is the main cause of initial catalyst decay, with no sintering or oxidation of Ni sites being observed. As reaction proceeds, a deactivation front is observed along the reforming catalytic bed, with coke location within the catalyst, and its nature and composition depending on the volatile composition reaching each axial position in the bed. At the inlet section of the catalytic bed (A1), the coke is deposited on Ni sites and is of rather oxygenated nature. At further axial bed locations, the catalyst is in contact with a volatile stream whose composition has been considerably modified, which leads to the formation of a more structured coke with higher graphitization degree and made up of more condensed polyaromatic compounds. Moreover, the coke deposited on all deactivated samples does not present any specific morphology, which is evidence of its amorphous structure regardless the bed location and reaction time.

Key words: Biomass, Pyrolysis, Steam reforming, Deactivation, Coke deposition, Hydrogen, Bio-oil