2019 AIChE Annual Meeting

(560b) “H2 -Free” Hydrodeoxygenation of Guaiacol over Ni-Mo/CeO2-C Nanocatalysts

Authors

Laura Pastor-Perez - Presenter, University of Surrey
Wei Jin, University of Surrey
Juan Jose Villora Pico, University of Alicante
Antonio Sepúlveda-Escribano, University of Alicante
Tomás Ramirez-Reina, University of Surrey

H2-free hydrodeoxygenation
of guaiacol over Ni-Mo/CeO2-C nanocatalysts

 

W. Jin 1, L. Pastor-Pérez 1,2*, J.J.
Villora-Picó2, S.Gu, A.
Sepúlveda-Escribano2, T. R. Reina 1*

 

1 Chemical and Process Engineering
Department, University of Surrey, Guildford, UK

2 Departamento de Química
Inorgánica, Instituto Universitario de Materiales de Alicante, Alicante, Spain

*Autor principal: l.pastorperez@surrey.ac.uk

 

1. Introduction

Catalytic
hydrodeoxygenation (HDO) is a fundamental technology to
achieve the effective upgrading of bio-oil with low emission. Currently, the
widespread implementation of HDO is limited by the supply of high pressure H2
(4-20 MPa). To date, several methods (e.g.
catalytic transfer hydrogenation (CTH), reforming followed by HDO, the
combination of metal oxidation with water and HDO and non-thermal plasma (NTP)
technology

1 ) have been proposed which could achieve the
deoxygenation with in-situ hydrogen
generation. It is noteworthy that metal oxidation with H2O (i.e. Zn) followed by subsequent HDO is
an attractive approach due to cheap water is used as the hydrogen source.
Nevertheless, the regeneration of metal requires high energy input 2-3 limiting its industrial application. Undoubtedly,
it is ideal to use water as the hydrogen source during HDO process considering
readily available and cheap advantages of water over other candidates.
Accordingly, we propose a novel HDO method to realize the in-situ HDO suppressing the supply of external H2. It is
envisioned that water would undergo splitting on the catalytic surface to
produce hydrogen. Hydrogen can further participate in the HDO of bio-oil to
faciliate the oxygen removal purpose. Ni-based catalysts are promising candidates for in-situ HDO process by tuning the support composition and/or
including promoters to adjust their catalytic functions. In this work, Ni-based
CeO2 and/or activated carbon
supported catalysts were synthesized, characterized and tested in guaiacol HDO
water-only reaction system. This novel method brings a new perspetive in the
development of econimically viable bio-oil upgrading technologies.

 

2. Experimental

CeO2-C (10wt.%
CeO2) was prepared in advance before the synthesis of Ni-based
catalysts. Five catalysts namely, Ni/CeO2, NiMo/CeO2,
Ni/C, Ni/CeO2-C and NiMo/CeO2-C
(with 15 wt.% Ni and 2 wt.% Mo) were synthesized by wet impregnation method and
characterized by H2-TPR, XRD, N2-adsorption, TEM, XPS and
Raman analysis. Prior to the activity tests, catalysts were activated at 400 oC for 1h under H2 atmosphere. The
catalytic performances of catalysts for guaiacol HDO
process were tested in a high pressure batch reactor (Parr Series 5500 HPCL
Reactor) by feeding 50 mL of a 0.01 mg/mL guaiacol
solution and 200 mg of catalyst at 250 oC
for 4h. After the reaction, the catalyst was collected by filtration. Products
were separated from water by using ethyl acetate and then analyzed by GC/FID
and GC/MS.

 

3. Results and discussion

The XRD patterns of
Ni-based catalysts after activation were shown in Figure 1.It is clear that
ceria and Ni dispersion are much better when activated carbon are used as
primary support. The Ni and ceria particle sizes are smaller in the carbon
supported materials. The textural properties summarised in Table 1 also
indicate the suitability of activated carbon to achieve large surface areas. The catalytic
performance of all studied catalysts is presented in Figure 2. C-containing
catalysts exhibited higher activity compared to CeO2 supported
catalysts. For instance, 22 % conversion of guaiacol is obtained in HDO over Ni/CeO2-C
catalyst,


Fresh                                          Spent

 

which is a significant

Text Box:<br /> Figure 1 XRD patterns of reduced catalysts<br /> Table 1 Textural properties of catalysts SBET (m2/g) Vmicro (cc/g)a Vtotal (cc/g)<br /> Ni/CeO2 78 0.029 0.064<br /> NiMo/CeO2 46 0.017 0.069<br /> Ni/C 1062 0.378 0.85<br /> Ni/CeO2-C 1027 0.368 0.79<br /> NiMo/CeO2-C 1017 0.364 0.79<br /> result in the Text Box:<br /> Figure 2. Activity of catalysts during in-situ HDO process<br /> Figure 3. Selected TEM images of Ni/CeO2-C<br /> case of water-only HDO reaction system. Regarding the
characterization of spent samples, no metal sintering and minor
concentration of carbon deposition were observed in the TEM images (Figure 3)
and also by XRD and Raman.

 

4. Conclusions

A novel
approach consisting on the combination of water splitting and subsequent hydrodeoxygenation (HDO) is proposed in this work with the
aim to suppress the supply of H2 to the HDO reactor. CeO2-C
supported catalysts performed high HDO ability compared to CeO2-supported
catalysts in guaiacol in-situ HDO process. The high HDO activity of CeO2-C
supported catalysts is likely attributed to the high dispersion and small
particle size of active phase along with the high surface area of catalysts.
The proposed novel method by using available and cheap water as hydrogen source
in HDO reaction is an interesting alternative which opens new research
possibilities to achieve low-cost bio-oil upgrading process.

 

References

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3. Cheng, S.; Wei, L.; Julson,
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