Oil-Dri presented new research on improving Renewable Diesel feedstock quality at the 2025 AOCS Annual Meeting. This blog highlights findings from the presentation.
Renewable Diesel Processing
The hydrotreatment process to create renewable diesel from fats and oils utilizes expensive catalysts. These catalysts are highly susceptible to degradation from contaminants, in the form of trace elements, in the feedstocks. The removal of trace element contaminants is crucial for cost-effective renewable diesel production. A pre-treatment process is usually employed to remove these trace element contaminants such as phosphorus-compounds.
Study Highlight 1: Increasing Pretreatment Temperature Improved Phosphorus Removal
Pre-treatment process parameters were assessed to determine the most efficient conditions for contaminant removal. Bench-scale testing was performed using commercially sourced canola and soybean oil feedstocks.
Pretreatment temperature significantly impacted trace element contaminant removal. Optimizing pre-treatment temperature from 80°C to 120°C had the same effect as increasing the clay dosage from 1% to 1.35%
| Pre-Treatment Temperature | Post-Treatment Concentration (ppm) | ||
| °C | °F | Phosphorus | Sulfur |
| 80 | 176 | 2.41 | 18.2 |
| 100 | 212 | 1.93 | 17.0 |
| 120 | 248 | 1.78 | 15.2 |
Interestingly, this trend continued even passed recommended processing temperatures:
Study Highlight 2: Oil Moisture Also Impacted Phosphorus Removal
The results of this study indicate that the level of impact of processing conditions on phosphorus removal is dependent on the oil quality. In the tested canola oil, changing the oil moisture had a far greater impact on phosphorus removal than changing the temperature. However, in the tested soybean oil, oil moisture and temperature had a similar impact with temperature changes being slightly more advantageous for trace element contaminant reduction.
Summary
Process conditions such as temperature and oil moisture significantly impacted trace element contaminant removal. Optimizing renewable diesel pre-treatment process conditions can both improve cost efficiency and increase the lifetime of the downstream catalyst. Oil-Dri’s technical service team is available to support customers with the optimization of renewable diesel processes.