Catalytic hydroprocessing of fatty acid methyl esters to jet fuels

Liangguang Chena,b, Junying Fua,b, Lingmei Yanga, Limei Liua,b, Pengmei Lva*, Zhenhong

Yuana*

a Key Laboratory of Renewable Energyï¼?Guangzhou Institute of Energy Conversionï¼?Chinese

Academy of Sciencesï¼?Guangzhou 510640ï¼?Chinaï¼?

b University of Chinese Academy of Sciencesï¼?Beijing 100049ï¼?Chinaï¼?

* Corresponding author E-mail address: [lvpm@ms.giec.ac.cn] (P.M. Lv)

* Corresponding author E-mail address: [yuanzh@ms.giec.ac.cn] (Z.H. Yuan)

Abstract: Global demands for cleaner jet fuel due to the depleting crude oil reserves and climate change are on the rise. Now renewable jet fuels has come under the public spotlight in terms of their contribution to greenhouse gas (GHG) emissions reduction and fuel sulfur content and fuel aromatic content reduction strategy, lessening aviationâ??s impact on air quality. The catalytic hydrodeoxygenation of fatty acid methyl esters (FAMEs) derived from palm oil to obtain composition of jet fuels rich in straight-chain and isomerization alkanes is a synthetic strategy that solves some of these problems. In light of this, Ni/HZSM-5 catalysts were prepared by incipient wetness impregnation. The physicochemical properties of the catalysts was characterized by XRD, SEM, N2-adsorption, NH3-TPD, Py-IR and TG techniques and their catalytic performance was tested in hydrodeoxygenation (HDO) of FAMEs to jet fuels on a high-pressure fixed bed reactor with on line analysis. The influence of reaction conditions like temperature, pressure, LHSV and different ratios of Si/Al of the catalysts etc. were studied in detail. It has been indicated that NiO aggregates dispersed on the surface of support obviously increased the acidity after H2 reduction, and thus significantly affected their catalytic performance. Pressure and temperature played crucial roles in the reaction and metal center catalyzed hydrodeoxygenation of FAMEs when acid sites in the catalysts were chiefly involved in isomerization of the intermediates. The optimal reaction condition was exhibited with high purified H2 of
50ml/min and H2 pressure of 0.8 MPa in 553K at the LHSV of 4 h-1, where the 83.1%
high yield of C8-C18 liquid hydrocarbons and suitable isomerization selectivity of 30.6% were obtained. To demonstrate its potential for practical applications, stability of the catalyst over the reaction course should be studied. It has been found that the life time
of this catalyst in a fixed-bed reactor has been shown in 120h, when the conversion of FAMEs was decreased to below 50%. The deactivation of the catalyst mainly was caused by the carbon deposition and the blockage of FAMEs from TG analysis.

Key words: jet fuels; hydroprocessing; HZSM-5; FAMEs;