Biomass Diesel via Thermal Cracking and Hydrotreating
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Solution Overview
Problem
Catalytic hydrotreating of biomass-derived diesel fuels requires large quantities of hydrogen and is inefficient for low-quality waste triglyceride feedstocks due to catalyst deactivation by contaminants, leading to high operating costs and reduced reactor efficiency.
Innovation Solution
A two-step process involving thermal cracking to partially convert triglycerides into middle distillates, followed by catalytic hydrotreating, which reduces oxygen content and hydrogen consumption, producing diesel fuels with high cetane values and low sulphur content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If catalytic hydrotreating is performed on low-quality waste triglyceride feedstocks, then diesel fuel production is achieved, but catalyst deactivation occurs rapidly due to contaminants
Solution Approach 1:
The patent applies preliminary action by implementing a thermal cracking step before catalytic hydrotreating. This pre-treatment step breaks down the triglyceride molecules and removes contaminants from low-quality waste feedstocks, preparing them for subsequent hydrotreating. This prevents catalyst deactivation during the main process, extending catalyst life while maintaining diesel fuel production efficiency.
2Manufacturing precision
If catalytic hydrotreating is performed to produce high-cetane diesel fuels, then fuel quality is improved, but large quantities of hydrogen are consumed
Solution Approach 1:
The thermal cracking pre-treatment step performs preliminary action by partially converting triglycerides into middle distillates with reduced oxygen content before hydrotreating. This reduces the hydrogen requirement in the subsequent catalytic hydrotreating step, as less oxygen needs to be removed from the feedstock, thereby producing high-cetane diesel fuel with lower hydrogen consumption.
Solution Approach 2:
The patent applies parameter changes by modifying the physical and chemical state of the feedstock through thermal cracking. The triglycerides are converted into middle distillate fractions with different molecular weight distributions and reduced oxygen content. These parameter changes in the feedstock composition directly reduce the hydrogen consumption during hydrotreating while maintaining the desired cetane value.
3Productivity
If catalytic hydrotreating is performed on heterogeneous waste grease feedstocks, then diesel fuel is produced, but operating costs increase due to large catalyst quantities required
Solution Approach 1:
The thermal cracking step performs preliminary action by homogenizing and cleaning the heterogeneous waste grease feedstock before it enters the catalytic hydrotreating unit. This pre-treatment removes contaminants and stabilizes the feedstock composition, reducing the quantity of catalyst needed and lowering operating costs while maintaining diesel fuel production efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process effectively produces diesel fuels with cetane values of at least 70, sulphur content below 10 ppm, and improved cold-flow properties, while significantly reducing hydrogen usage and extending catalyst life, making the process more economically viable for low-quality feedstocks.
Implementation Method 1
pretreating the triglyceride feedstocks by thermal cracking to partially convert the triglycerides and produce a middle distillates stream
Implementation Method 2
catalytically hydrotreating the middle distillate fraction to produce high cetane value diesel fuels
Implementation Method 3
catalytically hydrotreating the middle distillate fraction to produce high cetane value diesel fuels
Data Source
AI summary
A method is taught for producing diesel fuels of high cetane value from a triglyceride feedstock, comprising pretreating the triglyceride feedstock by thermal cracking to partially convert the triglycerides and produce a middle distillates stream, and catalytically hydrotreating the middle distillate fraction to produce high cetane value diesel fuels. A biomass-derived diesel fuel is also taught having sulphur content below 10 ppm, a cetane-value of at least 70, a cloud point below 0° C. and a pour point of less than −4° C. A blended diesel fuel is also taught comprising 5 to 20 vol. % of the biomass-derived diesel fuel of the present invention and 80 to 95 vol. % of a petroleum diesel, based on total volume of the blended diesel fuel.