Partially Reduced Catalysts for Selective BioQAV Production
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Solution Overview
Problem
Current processes for producing renewable aviation kerosene (bioQAV) face challenges in achieving high yields and quality suitable for aviation kerosene specifications, particularly in reducing freezing point and fouling point, while also generating high molecular weight linear paraffins and minimizing hydrogen consumption and by-product gases.
Innovation Solution
A process involving multiple catalytic stages, including hydrotreatment and selective hydrocracking using partially reduced group VIB and group VIII metal oxide catalysts, which converts plant oils and animal fats into bioQAV with high aromatic compound concentration, suitable for blending with fossil kerosene, and produces high molecular weight linear paraffins alongside naphtha and diesel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sulfide catalysts (NiMo and CoMo) are used for hydrorefining plant oils, then high cetane number is achieved, but low temperature flow properties (pour point) are impaired and H2S generation requires amine treatment units
Solution Approach 1:
The patent changes the chemical state of the catalyst from sulfide form to partially reduced oxide form. This parameter change eliminates H2S generation, removes the need for amine treatment units, and improves low temperature flow properties while maintaining high cetane numbers through selective hydrocracking and hydroisomerization
Solution Approach 2:
The patent applies different catalytic functions in different reactor zones or stages. The partially reduced catalyst provides selective activity for hydrocracking and hydroisomerization, creating local quality differences in product distribution that improve both cetane number and low temperature flow properties without generating H2S
2Reliability
If hydrocracking reactions are employed to reduce carbon atoms in the chain, then diesel fuel quality is improved, but hydrogen consumption increases and by-product gases (CO, CO2, CH4) are generated
Solution Approach 1:
The patent employs partial hydrocracking rather than extensive cracking. The partially reduced catalyst provides controlled cracking activity that reduces molecular weight to achieve fuel quality specifications while minimizing over-cracking that would excessive hydrogen consumption and generate unwanted by-product gases
Solution Approach 2:
The patent changes the catalyst reduction state to partially reduced form, which modifies the hydrocracking activity parameter. This optimization allows achieving fuel quality improvement with reduced hydrogen consumption by controlling the extent and selectivity of cracking reactions
3Reliability
If plant oils are converted directly into extra-quality diesel fuel using hydrorefining, then high cetane number is achieved, but aromatic compound concentration is reduced and freezing point is impaired
Solution Approach 1:
The patent segments the conversion process into selective hydrocracking and hydroisomerization stages using the partially reduced catalyst. This segmentation allows controlled modification of molecular structure that improves cetane number while preserving aromatic compounds and improving freezing point through selective isomerization rather than complete saturation
Solution Approach 2:
The patent changes the catalyst state to partially reduced oxide form, which modifies reaction selectivity parameters. This enables simultaneous improvement of cetane number through controlled cracking while preserving aromatic content and improving freezing point through selective hydroisomerization, avoiding complete saturation that would impair fuel composition stability
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 achieves high yields of bioQAV with improved quality, reduced hydrogen consumption, and lower by-product gas generation, meeting aviation kerosene specifications and generating valuable high molecular weight linear paraffins.
Implementation Method 1
using partially reduced group VIB and group VIII metal oxide catalysts in a hydrogen atmosphere
Implementation Method 2
Hydrogenation of plant oils and animal fats (triacylglycerides) combined with mineral oil is known from U.S. Pat. No. 2,163,563
Data Source
AI summary
The present invention relates to a process for the conversion of plant oils, animal fats, waste food oils and carboxylic acids into renewable liquid fuels, such as bio-naphtha, bioQAV and renewable diesel, for use in combination with fossil fuels. The process is composed of two steps: hydrotreatment and hydrocracking. The effluent from the hydrotreatment step contains aromatics, olefins and compounds resulting from the polymerization of esters and acids. This is due to the use of partially reduced catalysts without the injection of a sulfiding agent and allows for the production of bioQAV of suitable quality for use in combination with fossil kerosene. Concurrently, the process generates, in addition to products in the distillation range of naphtha, kerosene and diesel, high molecular weight linear paraffins (up to 40 carbon atoms).