Production of hydrogen, alkanes and polyols by aqueous phase processing of wood-derived pyrolysis oils
Production of hydrogen, alkanes and polyols by aqueous phase processing of wood-derived pyrolysis oils
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DOI：
10.1039/b912522c
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发表时间：
2009-09
期刊：
影响因子：
9.8
通讯作者：
T. Vispute;G. Huber
中科院分区：
文献类型：
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作者：
T. Vispute;G. Huber
热解油是衍生自木质纤维素生物质的最便宜的液体燃料。然而，热解油是一种质量非常差的液体燃料，不能用于传统的柴油机和内燃机。在本文中，我们表明，氢，烷烃（范围从C1到C6）和多元醇（乙二醇，1，2-丙二醇，1，4-丁二醇）可以从木材衍生的热解油（生物油）的水馏分中产生。热解油首先通过加入水而相分离成水性和非水性部分。生物油的水相含有糖、脱水糖、乙酸、羟基丙酮、糠醛和少量愈创木酚。在125-175 °C和68.9巴下，用Ru/C催化剂使水性部分经受低温氢化。氢化步骤将生物油中的各种官能团（包括醛;酸;糖）转化为相应的醇。在该低温氢化步骤中还产生不期望的甲烷和轻质气体。在该步骤中获得二醇（范围从C2至C4）和山梨糖醇作为主要产物。在低温氢化步骤之后，可以分别通过水相重整（APR）或水相脱水/氢化（APD/H）产生氢气或烷烃。在265 °C和55.1巴下用1重量% Pt/Al 2 〇 3催化剂进行APR。氢的选择性高达60%的观察。氢气选择性是空速的函数。在260 °C和51.7巴下使用4wt%Pt/SiO2-Al 2 O3催化剂用于通过APD/H的烷烃生产。当从生物油原位产生氢气时，对于0.96 h-1的WHSV，获得35%的碳转化为气相产物，烷烃选择性为45%。外供氢可提高烷烃选择性。当在生物油的水相中加入HCl并由外部提供氢气时，烷烃选择性可高达97%。为进一步的生物油转化研究的模型化合物的建议。
Pyrolysis oils are the cheapest liquid fuel derived from lignocellulosic biomass. However, pyrolysis oils are a very poor quality liquid fuel that cannot be used in conventional diesel and internal combustion engines. In this paper we show that hydrogen, alkanes (ranging from C1 to C6) and polyols (ethylene glycol, 1,2-propanediol, 1,4-butanediol) can be produced from the aqueous fraction of wood-derived pyrolysis oils (bio-oils). The pyrolysis oil was first phase separated into aqueous and non-aqueous fraction by addition of water. The aqueous phase of bio-oil contained sugars; anhydrosugars; acetic acid; hydroxyacetone; furfural and small amounts of guaiacols. The aqueous fraction was subjected to a low temperature hydrogenation with Ru/C catalyst at 125–175 °C and 68.9 bar. The hydrogenation step converts the various functionalities in the bio-oil (including aldehydes; acids; sugars) to corresponding alcohols. Undesired methane and light gases are also produced in this low-temperature hydrogenation step. Diols (ranging from C2 to C4) and sorbitol are obtained as major products in this step. After the low temperature hydrogenation step either hydrogen or alkanes can be produced by aqueous-phase reforming (APR) or aqueous-phase dehydration/hydrogenation (APD/H) respectively. APR was done with a 1 wt% Pt/Al2O3 catalyst at 265 °C and 55.1 bar. Hydrogen selectivities of up to 60% were observed. The hydrogen selectivity was a function of space velocity. A 4 wt% Pt/SiO2-Al2O3 catalyst at 260 °C and 51.7 bar was used for alkane production by APD/H. The carbon conversion to gas phase products of 35% with alkane selectivity of 45% was obtained for a WHSV of 0.96 h−1 when hydrogen is produced in situ from bio-oil. Alkane selectivity can be improved by supplying hydrogen externally. Alkane selectivities as high as 97% can be obtained when HCl is added to the aqueous-phase of the bio-oil and hydrogen is supplied externally. Model compounds for further bio-oil conversion studies are suggested.