Hydroisomerization Recycle Hydrocracking for Higher Aviation Fuel Yield
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Solution Overview
Problem
Existing processes for producing aviation fuel components from renewable raw materials have low yield and quality, and there is a need to reduce the formation of C1-C4 hydrocarbons, especially C1-C2 hydrocarbons, while prolonging the lifetime of hydroisomerization catalysts.
Innovation Solution
A process involving hydroisomerization of a paraffinic hydrocarbon feed with a hydroisomerization catalyst, followed by fractionation and hydrocracking of a recycle stream to enhance the yield and quality of aviation fuel components, using a hydrocracking catalyst capable of both cracking and isomerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydroisomerisation process is used to produce aviation fuel components, then the process is simple, but the yield of aviation fuel components is low and quality is poor
Solution Approach 1:
The process is divided into multiple stages: first hydroisomerisation reactor, then fractionation unit, followed by second hydroisomerisation reactor for the recycle stream. This segmentation allows each stage to be optimized for specific functions, improving overall aviation fuel component yield while managing complexity through modular design
Solution Approach 2:
The fractionation unit separates and recycles the heavy non-aromatic fraction (C15+) back to the first reactor for further processing. This recovery loop converts heavy fractions that would otherwise be low-value products into additional aviation fuel components, significantly improving yield
2Manufacturing precision
If hydroisomerisation is performed to improve fuel quality, then i-paraffin content increases, but C1-C4 hydrocarbon formation increases and catalyst lifetime decreases
Solution Approach 1:
The recycle stream from fractionation is continuously fed back to the first hydroisomerisation reactor for further processing. This continuous action allows progressive conversion of heavy fractions into aviation fuel components over multiple passes, improving quality while controlling gas formation through optimized residence time and catalyst contact
Solution Approach 2:
Different operating parameters are applied in different reactors: the first reactor operates with parameters optimized for converting heavy fractions with lower gas formation, while the second reactor handles the recycled stream with adjusted parameters to maximize aviation fuel component yield while minimizing C1-C4 formation
3Manufacturing precision
If severe hydroisomerisation conditions are applied to improve fuel quality, then aviation fuel component quality improves, but catalyst lifetime decreases
Solution Approach 1:
The hydroisomerisation process is segmented into two separate reactors with different catalysts and operating conditions. The first reactor uses a catalyst optimized for heavy fraction conversion with milder conditions to preserve catalyst lifetime, while the second reactor handles the recycled stream with conditions optimized for aviation fuel component quality
Solution Approach 2:
The first reactor performs partial hydroisomerisation of the heavy fraction, converting it to intermediate products that are then further processed in the second reactor. This partial action in the first reactor reduces the severity required in any single reactor, extending catalyst lifetime while achieving the required final quality through the combined process
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 improves the yield and quality of aviation fuel components, enhances cold properties, and extends the catalyst lifetime by converting heavy hydrocarbons into valuable fuel components, particularly in the aviation fuel range, with a high content of i-paraffins and lower n-paraffins.
Implementation Method 1
subjecting the paraffinic hydrocarbon feed in a first reactor to hydroisomerisation (HI) in the presence of a hydroisomerisation catalyst to obtain a hydroisomerisation effluent
Implementation Method 2
subjecting the hydroisomerisation effluent to fractionation to separate from the fractionation at least a recycle stream comprising C16 n-paraffins
Implementation Method 3
subjecting a second reactor feed comprising the recycle stream to hydrocracking in a second reactor in the presence of a hydrocracking catalyst to obtain a recycle effluent
Data Source
AI summary
A process for producing at least one liquid transportation fuel component is provided. In the process, a paraffinic hydrocarbon feed is provided and subjected to hydroisomerisation to obtain a hydroisomerisation effluent; from which hydroisomerisation effluent a recycle stream is separated and subjected to hydrocracking to obtain a recycle effluent, the hydroisomerisation effluent and the recycle effluent being fed to fractionation, from which fractionation at least one liquid transportation fuel component is recovered.