Downflow Lipid Conversion and Upflow Regeneration Against Catalyst Plugging
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Solution Overview
Problem
Existing reactor systems face challenges with plugging and non-uniform fluid flows due to coke and impurity accumulation, which degrade performance in processing lipid feedstocks for hydrocarbon production.
Innovation Solution
A reactor system that alternates between a downflow reaction mode and an upflow regeneration mode, using a metal oxide catalyst on an oxide support to treat lipid feedstocks, with specific temperature and pressure controls to minimize plugging and channeling by combusting impurities and regenerating the catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous reaction mode operation is used to process lipid feedstock, then productivity is maintained, but catalyst plugging and non-uniform flow occur due to impurity accumulation
Solution Approach 1:
The reactor system alternates between reaction mode and regeneration mode in periodic cycles. During reaction mode, lipid feedstock is processed continuously. When catalyst deactivation reaches a threshold, the system switches to regeneration mode where air is introduced to burn off accumulated coke and impurities. This periodic switching restores catalyst activity while maintaining overall productivity through continuous operation of multiple reactors in sequence.
Solution Approach 2:
The system discards the deactivated catalyst surface covered in coke and impurities by introducing air for combustion, converting the harmful accumulated carbon into CO2 and H2O. The catalyst support structure is recovered and reused after regeneration, eliminating the need for complete catalyst replacement and reducing waste.
2Reliability
If upflow regeneration mode is used to remove coke, then catalyst is regenerated, but channeling and non-uniform flow occur
Solution Approach 1:
The system inverts the flow direction during regeneration compared to reaction mode. During reaction, downflow configuration processes the lipid feedstock. During regeneration, upflow configuration introduces air from the bottom to burn off coke. This inversion helps prevent channeling by distributing the regenerating flow uniformly through the catalyst bed, preventing localized hot spots and non-uniform regeneration.
Solution Approach 2:
The system changes operating parameters between modes: reaction mode operates at 450-550°C and 30-1450 psi, while regeneration mode operates at higher temperatures (400-800°C) and lower pressures (10-200 psi). These parameter changes optimize both catalyst regeneration efficiency and flow uniformity during the regeneration process.
3Productivity
If high pressure is used during reaction mode, then conversion efficiency improves, but plugging risk increases
Solution Approach 1:
The system periodically switches between high-pressure reaction mode (30-1450 psi) for efficient conversion and low-pressure regeneration mode (10-200 psi) to prevent and remove plugging. The low pressure during regeneration helps expand the catalyst bed and prevent channeling, while the high pressure during reaction maximizes conversion efficiency.
Solution Approach 2:
The system converts the harmful effect of coke accumulation into a beneficial regeneration process. By introducing air during regeneration mode, the accumulated coke is combusted to CO2 and H2O, cleaning the catalyst surface and restoring its activity. This transforms the plugging problem into an opportunity for catalyst revitalization.
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 alternating mode operation effectively reduces plugging and channeling, maintaining uniform fluid flow and catalyst efficiency, producing a high-quality bio-oil feedstock suitable for refinery processing.
Implementation Method 1
treating the lipid feedstock to produce a treated stream that comprises a condensable oil fraction having a lower content of oxygen and impurities than the lipid feedstock
Implementation Method 2
providing an input of air optionally diluted with steam or inert gas into a bottom portion of the reactor such that the air flows upward through the catalyst particles; maintaining a temperature of 400° C. to 800° C., thereby causing combustion of combustible solids on the catalyst particles and thereby regenerating the catalyst particles
Data Source
AI summary
A reactor system includes a reactor that treats a lipid feedstock using a metal oxide catalyst to produce a treated stream comprising a bio-oil. The reactor system includes a catalyst zone in which the metal oxide catalyst reacts with the lipid feedstock to produce the treated stream. The reactor system operates in a reaction mode, during which the lipid feedstock flows in a downward direction through the metal oxide catalyst to produce the treated stream. Alternately, the reactor also operates in a regeneration mode, during which coke is burned from the metal oxide catalyst thereby regenerating the metal oxide catalyst. In one aspect, a regeneration mode pressure is less than a reaction mode pressure within the reactor to fluidize the catalyst.