Influence of Pressure on Product Composition and Hydrogen Consumption in Hydrotreating of Gas Oil and Rapeseed Oil Blends over a NiMo Catalyst

Josef Blažek,Pavel Šimáček,Petr Straka,Martin Staš,Daria Toullis

doi:10.3390/catal11091093

Josef Blažek, Pavel Šimáček + Show 3 more

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https://doi.org/10.3390/catal11091093

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Abstract

This study describes the co-hydrotreating of mixtures of rapeseed oil (0–20 wt%) with a petroleum feedstock consisting of 90 wt% of straight run gas oil and 10 wt% of light cycle oil. The hydrotreating was carried out in a laboratory flow reactor using a sulfided NiMo/Al2O3 catalyst at a temperature of 345 °C, the pressure of 4.0 and 8.0 MPa, a weight hourly space velocity of 1.0 h−1 and hydrogen to feedstock ratio of 230 m3∙m−3. All the liquid products met the EU diesel fuel specifications for the sulfur content (<10 mg∙kg−1). The content of aromatics in the products was very low due to the high hydrogenation activity of the catalyst and the total conversion of the rapeseed oil into saturated hydrocarbons. The addition of a depressant did not affect the cold filter plugging point of the products. The larger content of n-C17 than n-C18 alkanes suggested that the hydrodecarboxylation and hydrodecarbonylation reactions were preferred over the hydrodeoxygenation of the rapeseed oil. The hydrogen consumption increased with increasing pressure and the hydrogen consumption for the rapeseed oil conversion was higher when compared to the hydrotreating of the petroleum feedstock.

Highlights

The production of renewable fuels has been growing worldwide driven by government requirements and incentives which are mainly linked to efforts to reduce greenhouse gas emissions
At 8 MPa, ca 90% of the tricyclic aromatic hydrocarbons (TAHs) and dicyclic aromatic hydrocarbons (DAHs) were converted to DAHs and monocyclic aromatic hydrocarbons (MAHs), respectively
At 4 MPa, only 70% of the TAHs and DAHs were converted to DAHs and MAHs, respectively

Summary

Introduction

The production of renewable fuels has been growing worldwide driven by government requirements and incentives which are mainly linked to efforts to reduce greenhouse gas emissions. The hydrotreating of vegetable oils and animal fats is an excellent way to produce a high-quality renewable diesel fuel component. This diesel fuel component is commonly called Hydrotreated Vegetable Oil or Hydrodeoxygenated Vegetable Oil (HVO), Hydrotreated Esters and Fatty Acids (HEFA), renewable synthetic diesel, or renewable paraffinic diesel fuel from the hydrotreatment. Vegetable oils and animal fats are composed mainly of C14–C24 fatty acid triglycerides, while the C18 fatty acid triglycerides are often the most abundant ones. Unsaturated fatty acids with one or more double bonds dominate in most vegetable oils and are common in fish oils. Saturated fatty acids are common in fats from mammals (pork fat, tallow) [1,2]

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