Catalytic processes to produce transportation fuels (e.g., diesel, and jet fuel) from biomass have beenextensively investigated by the requirement to replace petroleum-based fuels with sustainable carbon source and thus to decrease $CO_2$ emission. Especially, vegetable oils and microalgal oils were regarded as a promising feedstock for producing fuels because they consist of triglycerides containing fatty acid units (generally $C_{12}-C_{22}$) which can be converted to transportation fuels. Most representative commercialized conversion technology is the transesterification of triglycerides with alcohols to produce alkyl esters. Ester-types biodiesel, however, still has a relatively high oxygen content, poor cold flow property, and low thermal stability, limiting its direct application as fuels. With this regard, extensive scientific efforts have recently been paid for the hydroconversion of triglycerides into oxygen-free hydrocarbons. The reaction involves (i) hydrogenation of unsaturated bond in triglycerides, (ii) hydrogenolysis of triglycerides into fatty acids, and (iii) decarboxylation, decarbonylation andhydrodeoxygenation of fatty acids to hydrocarbon. From above reaction pathway, normal paraffins can beobtained, and these products are further converted into paraffinic diesel or jet fuel by hydroisomerization or hydrocracking reaction.
In the present work, we investigated hydroconverison of triglyceride (palm oil and Aurantiochytrium microalgae species) into high quality paraffinic diesel and jet fuel. The results showed that hydroconversion of triglyceride using Pt supported $\gamma-Al_2O_3$ catalyst selectively produce the $C_{n-1}$ n-paraffins by decarbonylation/decarboxylation routes and almost theoretical yield can be obtained. These n-paraffins have poor flow properties, hence, hydroisomerization reaction was carried out to obtain high quality paraffinic diesel fuels, and adequate reaction condition is important to meet the international standard specification such as cetane number and flow properties. Also, n-paraffins are converted into jet fuel by hydrocracking reaction. In the hydrocracking reaction, chain length of fatty acids, reaction gas atmosphere, type of zeolite and mesoporosity have a huge effect to produce high quality jet fuel with high yield.
전세계적으로 석유 기반 연료를 대체하기 위해 바이오매스로부터 수송연료를 생산하는 연구가 활발히 진행되고 있다. 특히, 식물성 및 미세조류로의 경우 수송연료와 비슷한 탄소수를 가지는 지방산으로 구성된 트리글리세라이드를 포함하기 때문에 이를 이용한 전환이 각광받고 있다. 따라서, 상기 언급한 원료로부터 수소화 반응을 통해 수송연료 영역에 해당하는 노말 파라핀을 생산할 수 있으며, 추가적인 수첨이성화/수첨분해 반응을 통해 흐름 성질이 개선된 고품질의 디젤 및 항공유를 생산할 수 있다.
본 연구에서는 팜유 및 오란티오사이트리움 미세조류 종을 이용하여 디젤 및 항공유 생산에 관한 연구를 진행하였다. 그 결과, 상기 언급한 원료를 백금이 담지된 촉매를 이용해 수소화 반응을 진행할 경우 지방산에 존재하는 탄소 수보다 하나 적은 노말 파라핀이 선택적으로 생산되는 것을 확인했으며, 추가적인 수첨이성화 반응을 통해 흐름성질을 개선할 경우 높은 세탄가를 가지는 고품질의 디젤을 생산할 수 있었다. 또한, 생산된 노말 파라핀을 수첨분해 반응을 통해 전환할 경우 항공유 영역에 해당하는 탄화수소를 얻을 수 있었으며, 사용한 촉매에 따라 항공유 영역의 수율 및 품질이 달라지는 것을 확인하였다.
