Olefin Feed Aromatic Removal via Alkylation Distillation
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Solution Overview
Problem
Existing alkylation processes in petroleum refining face challenges in efficiently removing aromatic components from olefin feeds, which leads to increased acid consumption and downstream issues due to the formation of alkyl sulfonic acids, requiring stringent fractionation and additional capital investments for separate towers.
Innovation Solution
A process utilizing a single conventional fractionation tower to remove aromatic compounds from olefin feeds during the alkylation process, integrating the separation of aromatics with the recovery and concentration of dilute alkylate products, thereby reducing capital costs and acid consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aromatic components are not removed from olefin feeds, then the process is simpler and capital cost is lower, but acid consumption increases and downstream issues occur due to alkyl sulfonic acid formation
Solution Approach 1:
The patent extracts aromatic components from the olefin feed stream using a fractionation tower before the alkylation reactor. The aromatic compounds are separated and removed as a distinct stream, preventing them from entering the reactor and reacting with sulfuric acid to form alkyl sulfonic acids. This extraction approach directly addresses the acid consumption issue while maintaining process integration.
Solution Approach 2:
The fractionation step is performed preliminarily, before the alkylation reaction occurs. By removing aromatic components in advance from the olefin feed, the system prevents the formation of harmful by-products during the subsequent alkylation process. This preliminary separation action eliminates the need for downstream caustic wash units and reduces overall acid consumption.
2Manufacturing precision
If separate fractionation towers are used to remove aromatics, then aromatic removal efficiency is improved, but capital cost increases
Solution Approach 1:
The patent combines the fractionation function with the existing alkylation process infrastructure. The fractionation tower is integrated into the process flow, sharing utilities and control systems with the alkylation unit. This merging approach achieves effective aromatic separation while avoiding the capital cost of completely separate, standalone fractionation facilities.
Solution Approach 2:
The fractionation tower performs multiple functions: separating aromatic components from olefin feeds, concentrating dilute alkylate products, and preparing feed streams for subsequent processing. By designing the tower to handle multiple separation tasks, the system achieves high aromatic removal efficiency without requiring additional specialized equipment for each function.
3Manufacturing precision
If conventional fractionation towers are used, then aromatic separation is achieved, but acid spending rates increase
Solution Approach 1:
The patent applies local quality control by targeting specific aromatic compounds (BTX components) for removal at specific points in the process. The fractionation tower is designed to separate benzene, toluene, and xylene components with high selectivity, ensuring that only the problematic aromatic species are removed while preserving the valuable olefin feed composition for alkylation. This localized, selective removal minimizes unnecessary acid consumption.
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 approach effectively separates heavier components from olefin feeds, reducing acid spending rates and downstream issues, while providing a lower capital cost solution for incremental alkylation expansions by using existing equipment, and producing a BTX-free feed for alkylation.
Implementation Method 1
feeding an olefin containing hydrocarbon stream and a dilute alkylate product stream from a paraffin alkylation to a distillation zone, removing unreacted material from said hydrocarbon stream as overheads, and removing a more concentrated alkylate product stream and a portion of said aromatic compounds as bottoms
Data Source
AI summary
A process for the removal of aromatic compounds from an olefin feed to a paraffin alkylation is disclosed. The process may include feeding a olefin and aromatic containing hydrocarbon stream and a dilute alkylate product stream comprising alkylate product and unreacted material from the paraffin alkylation to a distillation zone and removing the unreacted material as overheads and removing a more concentrated alkylate product stream and a portion of the aromatic compounds as bottoms resulting in an improved alkylation process.