CAJ | 학술논문

鉴于生物油的高含氧量，将其轻质组分在温和条件下转化为以饱和醇为主要成分的含氧燃料可能成为生物油利用的新思路。该文以自制Raney-Ni为催化剂，研究在高压反应釜中反应温度（100～180℃）、氢气冷压（4～8 MPa）、催化剂用量（0.5～2 g）对生物油轻质组分催化加氢改质的影响；对Raney-Ni催化剂进行N2吸附脱附、X射线衍射（X-ray diffraction）、扫描电镜（scanning electron microscope）表征，分析催化剂失活机理，研究催化剂的重复使用性能。试验结果表明：反应温度和反应初压对生物油加氢产物分布的影响较大，在反应温度为140℃、氢气初压为6.0 MPa 时，产物中饱和醇的相对含量（以GC峰面积百分比计算）最高可达53.51%；当催化剂用量从0.5 g增加到1 g时，产物中饱和醇的含量显著提升，由25.42%提高到51.89%，进一步提高催化剂用量对饱和醇含量的提高影响不大；一次与二次催化剂催化生物油加氢反应产物中饱和醇含量由53.51%降为29.20%，活性显著降低可能与催化剂孔道内部及表面的活性中心被覆盖进而降低反应效率有关。加氢过程中，除有酮醛酚类化合物的加氢反应和酸与醇的酯化反应外，存在醇脱水成醚的反应发生。与烃类液体燃料相比，含氧燃料以其优异的燃烧性能逐渐被人们所青睐。将生物油的轻质组分加氢制备含氧燃料有望成为生物油的应用提供新思路。
감우생물유적고함양량，장기경질조분재온화조건하전화위이포화순위주요성분적함양연료가능성위생물유이용적신사로。해문이자제Raney-Ni위최화제，연구재고압반응부중반응온도（100～180℃）、경기냉압（4～8 MPa）、최화제용량（0.5～2 g）대생물유경질조분최화가경개질적영향；대Raney-Ni최화제진행N2흡부탈부、X사선연사（X-ray diffraction）、소묘전경（scanning electron microscope）표정，분석최화제실활궤리，연구최화제적중복사용성능。시험결과표명：반응온도화반응초압대생물유가경산물분포적영향교대，재반응온도위140℃、경기초압위6.0 MPa 시，산물중포화순적상대함량（이GC봉면적백분비계산）최고가체53.51%；당최화제용량종0.5 g증가도1 g시，산물중포화순적함량현저제승，유25.42%제고도51.89%，진일보제고최화제용량대포화순함량적제고영향불대；일차여이차최화제최화생물유가경반응산물중포화순함량유53.51%강위29.20%，활성현저강저가능여최화제공도내부급표면적활성중심피복개진이강저반응효솔유관。가경과정중，제유동철분류화합물적가경반응화산여순적지화반응외，존재순탈수성미적반응발생。여경류액체연료상비，함양연료이기우이적연소성능축점피인문소청래。장생물유적경질조분가경제비함양연료유망성위생물유적응용제공신사로。
Bio oil, for its simple preparation and low cost, had the potential to be one kind of substitute liquid fuel. In view of its high temperature, H2 pressure, and high oxygen content, hydrodeoxygenation (HDO) is very critical for hydrocarbon fuel. Upgrading the light phase of bio-oil might be a potential method and stable oxygenated compounds might be a kind of potential fuel for the application of bio-oil. In this paper, a Raney Ni catalyst was used for hydrogenating bio oil to saturated alcohols in the high pressure reaction kettle. The influences of temperature (100-180℃), initial pressure of hydrogen (4-8 MPa), the dosages and the recycle usage of the catalyst on the hydrogenation of bio-oil over the self-made Raney-Ni catalyst were discussed. X-ray Diffraction, Brunauer Emmett Teller, and a scanning electron microscope were used to investigate the deactivation mechanism. The results indicated that the reaction temperatures and the initial pressures of the hydrogen gas had an obvious effect on the conversion of the light composition of the bio oil. With the increasing of the reaction temperature to 140℃and the initial pressure to 6 MPa, the yield of saturated alcohols increased and reached the highest point of 53.51%. Meanwhile, the total content of stable alcohols and esters reached 64.62%. At this condition, there was no aldehyde detected in the product, and nearly 40%of the ketones were hydrogenated to alcohols. And also there was 1.77%of ether detected in the products which accounts for the dehydration happening from alcohols. With the increasing of temperature, the conversion of phenol increased. When the dosage of the catalyst increased from 0.5 g to 1 g, the content of saturated alcohols in the product increased from 25.42% to 51.89%. Over 0.5 g of Raney Ni catalyst, there were some unstable ketone compounds such as 1-hydroxy-butanone, 3-hydroxy-butanone, and hydroxyl-acetone in the products. When the dosage of Raney Ni catalyst increased, the content of saturated alcohols in the upgraded bio oil was little changed. Over fresh and once-used Raney Ni catalysts, the content of saturated alcohols decreased from 53.51%to 29.20%. The XRD results showed that the three characteristics of the diffraction peak intensity decreased significantly, and the heterogeneous metal skeleton crystal structure of the Raney Ni catalyst collapsed after use. The SEM results showed that after the hydrogenation reaction, the catalyst presented a black honeycomb solid surface and the activity on the surface was covered by coking. The deactivation of the catalyst may relate to the covering of the catalyst pore and the coking on the catalyst channel, which leads to a decrease of the catalyst’s activity and a reduction of the reaction efficiency. During the upgrading process, the ketones and the aldehydes compounds could be hydrogenated to alcohols, and the phenols could be hydrogenated to cyclohexanol and its derivatives. Apart from the hydrogenation reaction, the esterifications existed during the process, and the contents of acids decreased after hydrogenation to some extent. Compared with hydrocarbon fuel, oxygenated fuel for its good combustion performance becomes more popular. It might be a potential and novel way of upgrading bio-oil to oxygenated fuel.