Catalytic Hydroprocessing of Tire Pyrolysis Oil Distillates
Date
2022-12-16
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Abstract
Energy demand is still in the rising, as well as the environmental concerns related to the use of fossil fuels to meet it. Hence, the transition to alternative and renewable energy sources has become a priority. The production of tire pyrolysis oil (TPO) to eliminate waste tires and produce atmospheric distillates (IBP343°C) has great potential to reduce the amount of waste material and contribute to the energy transition. This work aimed to study the TPO atmospheric distillates upgrading capabilities using the hydrotreating (HDT) process and a new proprietary group of catalysts. First, catalyst Mo2C/Zeolite (P-1) was tested on a synthetic feedstock composed of model molecules emulating TPO atmospheric distillates. Results proved that the highest conversion of nitrogen and sulfur was achieved at 350°C and 0.3 h-1. Additionally, high conversion selectivity of the nitrogenated compounds was observed based on 100 % conversion of the quinoline model molecule. The previous experiment was followed by testing catalyst P-1 and another catalyst Mo2C/γ-Al2O3 (M-3) using a TPO naphtha/kero fraction (IBP-280°C). This test demonstrated that the acidity of the support was key to achieving higher levels of upgrading, nevertheless, it needed to be balanced with a higher hydrogenating function. Later, another set of experiments was performed using a TPO atmospheric distillates (IBP-343°C) fraction and catalysts M-3, P-2 and P-3, the last two with increasing hydrogenation functions. Results showed that catalyst P-3 reached sulfur and nitrogen levels conversion of 90% and 89%, respectively. Additionally, a study of the HDT products obtained in the last experiment was performed based on the distillation of the product into heavy naphtha (IBP-220°C) and diesel (220-343°C). Characterizing these cuts indicated that aromatic and polar compounds initially present in the heavy naphtha are easier to hydrogenate than those in the diesel fraction. Additionally, partial hydrogenation was observed in both cases due to the reduction of polyaromatic compounds and an increase in the tetralin family. Finally, a study on the reaction severity revealed that temperatures of 350°C, weight hourly space velocity of 0.1 h-1, pressure of 1,500 psig and Vol. H2/Oil of 1,200 are preferred for higher hydrogenation.
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Keywords
Hydrotreating, tire pyrolysis oil, distillates, upgrading, desulfurization, denitrogenation
Citation
Marti, J. (2022). Catalytic hydroprocessing of tire pyrolysis oil distillates (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.