Abstract
Efficient catalysts for simultaneous hydrodeoxygenation (HDO) and hydrodenitrogenation (HDN) are needed for the production of renewable fuels. In this study, Pt catalysts supported on SiO2, γ-Al2O3, SiO2-Al2O3, ZrO2, CeO2-ZrO2, Nb2O5, and TiO2 were studied for the hydrotreatment of n-hexadecanamide (C16 amide) to n-paraffins at 300°C and 80 bar H2. The catalysts favored HDO over HDN, and the initial differences in the nitrogen removal level were smaller than the differences in the oxygen removal level. The Lewis acid properties of the support influenced the initial C16 amide conversion route and HDO activity, which was reflected in the reaction network and condensation reaction selectivity of the catalysts. Pt/Nb2O5 and Pt/TiO2, with intermediate strength Lewis acid sites, initially favored the HDO of C16 amide to nitrogen-containing compounds. In contrast, the other catalysts converted C16 amide to oxygen- and nitrogen-containing compounds with similar selectivity. The HDO of the oxygen-containing compounds proceeded more efficiently on the Pt catalysts supported on oxides with weak Lewis acid sites (Pt/ZrO2, Pt/CeO2-ZrO2) than on the irreducible oxides with strong or no Lewis acid sites (Pt/γ-Al2O3, Pt/SiO2-Al2O3, Pt/SiO2). As the presence of oxygen-containing compounds suppressed HDN activity, the catalysts with the highest HDO activity eventually gave the highest paraffin yield, regardless of which oxygen removal pathway was favored.
| Original language | English |
|---|---|
| Pages (from-to) | 431-448 |
| Journal | Catalysis Science and Technology |
| Volume | 14 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2024 |
| MoE publication type | A1 Journal article-refereed |
Funding
Dr. Hua Jiang is acknowledged for the STEM images, and Ellen Järvinen is acknowledged for assistance with the batch reactor experiments. Dr. Yingnan Zhao and the Research Analytics department of Neste Corporation are acknowledged for the guidance with the acid site characterization and for access to the equipment that was used for the pyridine FTIR measurements. All members of the Neste-Aalto HDN catalyst development project group are gratefully acknowledged for fruitful discussions. This study was funded by Neste Corporation (Neste-Aalto HDN catalyst development project). The Bioeconomy and Raw materials research infrastructures at Aalto University and the OtaNano Nanomicroscopy Center were used for the study.
