植物油加氢脱氧反应路径的探究概要

植物油加氢脱氧反应路径的探究Oil scarcity,non-renewable resource,unpredictable prices and increasing environmental issues involved with petroleum-based fuels lead to the need for alternative sources to fulfill fuel needs. Industry and transportation, especially air trans-portation, play crucial roles in increasing the emission of greenhouse gases, which cause global warming. Therefore, it is necessary to develop an alternative fuel source that can replace non-renewable fossil fuels. The use of biomass-derived fuels in place of conventional fuels is an emerging field of interest, and studies are on-going to find a solution to avoid a future energy crisis. Hydrodeoxygenation, which converts biofeed to hydrocarbon fuels that have all the qualities of conventional fossil fuels, is one of the most interesting and promising techniques in this field. The hydrodeoxygenation of vegetable oils to biofuel is an area in development.随着世界经济的发展，全球性化石资源日益枯竭以及世界对全球气候的关注，发展可再生环境友好型能源变得十分紧迫。

生物燃料是一种新型、清洁的可再生能源。

目前越来越人把节能减排的希望寄托在生物燃料方面。

植物油燃料因可生物降解、能减少二氧化碳排放，对环境危害程度低，并可以从从可再生资源中获取，受到了人们的广泛关注。

植物油燃料有望成为重要的石油产品的替代品[1-3]。

Typical feedstocks for biofuels are vegetable oils with high energy contents.The major content in the vegetable oils is Omega-3 fatty acids.The chain length of fatty acids concentrates in the range of C12~24,植物油中的主要成分是脂肪酸甘油三酯，即一个甘油分子连接三个脂肪酸分子[4]。

每个脂肪酸分子的链长度主要集中在C12~24，且大多数是偶数碳。

常见植物油的结构如图1所示。

一般植物油含碳76~78wt%，含氢11.5~12.5wt%，含氧9~11wt%，密度在0.912~0.924kg/L 之间，分子量在800~960之间。

氧含量高是植物油的一大特点，高的氧含量对燃料的热值、安定性等都会产生很大的影响，植物油加氢脱氧是制备生物燃料的一种重要步骤。

R 2OOR1R 3OOOO图2 棕榈油中甘油三酯结构图Figure 2 The structure of triglyceride in palm oil植物油加氢脱氧过程包含了多个化学反应，主要有加氢饱和反应、加氢直接脱氧反应、加氢脱羧基反应、加氢脱羰基反应，同时还包括异构化、甲烷化等副反应。

加氢脱氧反应主要包括加氢直接脱氧反应、加氢脱羧基反应和加氢脱羰基反应三种反应路径。

棕榈油加氢反应途径如图3所示[5]：The process of vegetable oil hydrodeoxygenation contains a number of reactions.,which including Hydrogenation Saturated reaction、Direct Hydrogenation deoxygenation、Hydrogenation decarboxylation、Decarbonlation reaction of hydrogenation，also included side effects like Isomerization and Methanation. Hydrodeoxygenation reaction is made up of three kinds of reaction route:Direct hydrogenation deoxygenation、Hydrogenation decarboxylation and Decarbonylation reaction of hydrogenation.The palm oil hydrogenation reaction pathway is as illustrated in figure 3.图3棕榈油加氢反应途径Figure 3 Hydrotreating reaction paths of palm oil注：R1，R2，R3为甘油三酯中脂肪酸端的长链烷基或自由脂肪酸的长链烷基。

Note: R1，R2，R3 are the long-chain alkyl of one side of the fatty acid of triglycerides or free fatty acids’s.不同的反应路径，加氢反应后的产物和氢耗都有很大的不同。

加氢直接脱氧反应，生成物主要是丙烷、水和C16、C18等偶碳数烃；加氢脱羧基反应，生成物主要是丙烷、二氧化碳、和加氢脱羧基反应，生成物主要是丙烷、二氧化碳、和C15、C17等奇碳数烃；等奇碳数烃；加氢脱羧基反应生成物主要是丙烷、水、一氧化碳和和C15、C17等奇碳数烃。

以棕榈油为计算基础，三种路线的化学氢耗、柴油收率、水收率和丙烷收率如表3。

Different reaction paths lead to different products and hydrogen consumption when the hydrogenation is completed.The products of Deoxy direct hydrogenation reaction are mainly propane、water and even carbon number hydrocarbons such as C16、C18 .The products of Hydrogenation decarboxylation reaction are mainly propane、carbon dioxide and odd carbon number hydrocarbons such as C15、C17 .And the main product of Hydrogenation decarboxylation are pronane、water、carbon monoxide and other odd carbon number hydrocarbons such as C15、C17 .Base on the caculation of the palm oil ,the chemical hydrogen consumption 、the diesel yield、the water yield and the propane yield of the three reaction paths above can be figured out in Table 3表3不同脱氧路线的技术对比Table 3 The comparison with different paths of hydrodeoxygenation reaction反应路径化学氢耗/% 柴油收率/% 水收率/% 丙烷收率/%加氢直接脱氧2.8 85.5 12.6 5.1 加氢脱羰 1.4 80.6 6.3 5.1基0.7 80.6 -- 5.1加氢脱羧基随着化石燃料的供应日益紧张，以及环境保护的日益严格，以植物油做为燃料必须进行脱氧处理，加氢脱氧作为生产生物燃料的重要步骤，一直以来针对不同催化剂对模型化合物的加氢脱氧活性、选择性以及路线有许多研究报道[6-11]。

但在加氢直接脱氧、加氢脱羧基和脱羰基路线的反应机理研究不多，对植物油加氢脱氧的认识有待进一步深化。

With the increasingly tight supply of fossil fuels ,as well as increasingly stringent environmental protection,there are many reports about vegetable oil，which as fuel must be deoxygenated、Hydrodeoxygenation ，which as an important step in the production of bio fuels,and for the long run how the different catelysts impact on model compounds’s Hydrodeoxygenation activity、selectivity and reaction route.However, we have little research on the reaction mechanism of hydrogenation deoxidation and hydrogenation decarboxylation route. The understanding of Hydrodeoxygenation for vegetable oils to be further deepen.实验采用癸酸甲酯和棕榈油为原料，分别在小型固定床加氢装置和中型固定床加氢装置上探究在Ni-Mo/ Al2O3催化剂条件下植物油三种加氢脱氧反应路径的反应化学。