Dual-Reactor Hydroprocessing for Nitrogen-Tolerant Aviation Fuel
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Solution Overview
Problem
Existing processes for producing aviation fuel components from renewable raw materials face low yield, quality degradation, and catalyst deactivation issues, particularly due to nitrogen impurities, limiting the use of impure and heavier feeds.
Innovation Solution
A process involving dual-reactor hydroprocessing with catalyst monitoring and switching, where parameters indicative of deactivation are compared to predetermined values to switch the operation mode, using purer or nitrogen-free feeds to maintain catalyst activity and improve yield and quality of aviation fuel components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-reactor hydroprocessing process is used to produce aviation fuel components from renewable raw materials, then the process is simple, but the yield of aviation fuel components is low due to catalyst deactivation by nitrogen impurities
Solution Approach 1:
The single-reactor hydroprocessing process is segmented into two sequential reactors (Reactor A and Reactor B), each containing a hydrotreatment catalyst. Reactor A is dedicated to removing nitrogen impurities from the feed, while Reactor B produces the aviation fuel component. This segmentation protects the aviation fuel production catalyst (Reactor B) from nitrogen deactivation, thereby maintaining high yield and extending catalyst lifetime.
Solution Approach 2:
Reactor A acts as an intermediary unit that treats the renewable feedstock by removing nitrogen impurities before the cleaned feed enters Reactor B. This intermediary treatment step prevents direct contact between nitrogen-containing feeds and the aviation fuel production catalyst, resolving the contradiction between processing impure feeds and maintaining catalyst activity.
2Adaptability or versatility
If renewable raw materials with elevated nitrogen impurities are used to increase feedstock versatility, then the range of usable raw materials expands, but the catalyst deactivates faster and run-time decreases
Solution Approach 1:
The dual-reactor system segments the processing functions so that Reactor A handles nitrogen removal from diverse, impure renewable feeds, while Reactor B maintains stable aviation fuel production. This allows the system to adapt to various feedstock types with elevated nitrogen content without compromising catalyst lifetime in the fuel production reactor.
Solution Approach 2:
The nitrogen impurities that would normally harm the catalyst are converted into a beneficial separation function in Reactor A. By designing the first reactor specifically for nitrogen removal, the system transforms the harmful effect of nitrogen-containing feeds into an opportunity to protect the second reactor's catalyst, enabling use of versatile, impure renewable feedstocks while maintaining long catalyst run-times.
3Productivity
If continuous hydroprocessing operation is maintained to maximize productivity, then output is high, but catalyst quality decreases towards end of run
Solution Approach 1:
The continuous operation quality issue is resolved by segmenting the reactors so that Reactor A continuously removes nitrogen impurities from the feed, ensuring that Reactor B always receives high-quality, nitrogen-free feedstock. This segmentation maintains consistent aviation fuel component quality throughout continuous operation, preventing the quality degradation that would otherwise occur towards the end of catalyst runs.
4Reliability
If a dual-reactor system with nitrogen removal is implemented to protect the aviation fuel catalyst, then catalyst lifetime is extended, but the process complexity increases
Solution Approach 1:
While segmentation into two reactors does increase structural complexity, it extends catalyst lifetime in Reactor B by protecting it from nitrogen deactivation. The segmentation creates a dedicated nitrogen removal stage (Reactor A) that preserves the aviation fuel production catalyst (Reactor B), trading moderate system complexity for significant reliability improvement.
Solution Approach 2:
Reactor A serves multiple functions: it removes nitrogen impurities, protects downstream equipment, and prepares the feed for optimal processing in Reactor B. This multi-functionality justifies the added complexity by providing several benefits from a single reactor unit, including extended catalyst lifetime in Reactor B.
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 enhances the catalyst lifetime and yield of aviation fuel components, allowing the use of a broader range of impure and heavier feeds, with improved quality and extended run-time.
Implementation Method 1
subjecting a reactor A feed comprising the hydrocarbon feed to hydroprocessing in a reactor A in the presence of a hydrotreatment catalyst A
Implementation Method 2
in the presence of a hydrotreatment catalyst A to obtain a hydroprocessing effluent A
Implementation Method 3
feeding the hydroprocessing effluent B, optionally after separating from the hydroprocessing effluent B at least compounds gaseous at NTP, to fractionation, and recovering from the fractionation at least one or more liquid transportation fuel component(s)
Data Source
AI summary
Here is provided processes for producing at least one liquid transportation fuel component. In a first mode of running one of the processes, a hydrocarbon feed including nitrogen impurities is subjected to a hydroprocessing in reactor A in a presence of a hydrotreatment catalyst A to obtain a hydroprocessing effluent A, which is subjected, after degassing, to a catalytic hydroprocessing in reactor B to obtain a hydroteratment effluent B, which is fractionated, optionally after degassing, to obtain at least one liquid transportation fuel component, and/or at least an aviation fuel component. In the process, parameters indicative of deactivation of the hydrotreatment catalyst A are monitored and when these reach predetermined values, the process is switched to a second mode of running wherein the order of reactors A and B is changed so that a degassed hydroprocessing effluent B is fed to the reactor A.