Adsorbent Pre-treatment for FCC Feedstock Nitrogen Removal
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Solution Overview
Problem
The presence of nitrogen and poly-nuclear aromatics in heavy oil fraction feedstocks negatively impacts the performance of hydrocracking and fluid catalytic cracking units, leading to reduced efficiency and product quality, increased catalyst consumption, and higher emissions of sulfur and nitrogen oxides.
Innovation Solution
A process involving the use of packed bed or slurry columns filled with adsorbent materials like attapulgus clay, alumina, and activated carbon to absorb nitrogen and poly-nuclear aromatic molecules from the feedstock, followed by desorption and recycling of solvents for reuse, which treats the feedstock upstream of hydrocracking or fluid catalytic cracking units to produce a cleaner feedstock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heavy oil fraction feedstocks containing nitrogen and poly-nuclear aromatics are processed through hydrocracking or fluid catalytic cracking units, then the feedstock can be converted into fuel products, but the performance and efficiency of the cracking units deteriorates due to catalyst deactivation and reduced product quality
Solution Approach 1:
The patent applies preliminary action by implementing an adsorption treatment step before the hydrocracking or FCC process. The feedstock is pre-treated with adsorbent materials (such as attapulgus clay, alumina, silica, or activated carbon) to remove nitrogen and poly-nuclear aromatic compounds before entering the cracking unit. This preliminary removal prevents catalyst deactivation and maintains high conversion efficiency throughout the cracking process.
Solution Approach 2:
The patent uses adsorbent materials as intermediary substances between the feedstock and the cracking catalyst. These intermediaries (adsorbents) selectively bind to and remove harmful nitrogen and PNA compounds from the feedstock, protecting the cracking catalyst from deactivation while allowing the desired cracking reactions to proceed efficiently.
2Productivity
If feedstocks with high nitrogen and PNA content are used in hydrocracking units, then the processing capacity is maintained, but the product quality deteriorates with lower smoke points and cetane numbers
Solution Approach 1:
The patent applies the extraction principle by removing specific harmful components (nitrogen and poly-nuclear aromatic compounds) from the feedstock before processing. The adsorption step extracts these contaminants using selective adsorbent materials, ensuring that only cleaned feedstock enters the hydrocracker, thereby maintaining both processing capacity and product quality specifications.
3Duration of action of stationary object
If conventional feedstock treatment processes are used, then the hydrocracking unit can operate continuously, but higher emissions of sulfur and nitrogen oxides are produced
Solution Approach 1:
The patent removes nitrogen compounds from the feedstock before hydrocracking through adsorption, which prevents their conversion to nitrogen oxides during the cracking process. This preliminary removal of nitrogen sources enables continuous operation while significantly reducing harmful NOx emissions in the final product streams.
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
This process effectively removes nitrogen and poly-nuclear aromatics, improving the efficiency and quality of hydrocracking and fluid catalytic cracking processes, increasing catalyst activity and stability, reducing emissions, and enhancing the yield of gasoline while minimizing the production of undesirable side products.
Implementation Method 1
A process involving the use of packed bed or slurry columns filled with adsorbent materials like attapulgus clay, alumina, and activated carbon to absorb nitrogen and poly-nuclear aromatic molecules from the feedstock
Data Source
AI summary
A feedstream to an FCC unit is treated to remove or reduce the content of polynuclear aromatics and nitrogen-containing compounds by contacting the feedstream with an adsorbent compound selected from attapulgus clay, alumina, silica gel and activated carbon in a fixed bed or slurry column and separating the treated feedstream that is lower in the undesired compounds from the adsorbent material. The adsorbent can be mixed with a solvent for the undesired compounds and stripped for re-use.