C6 Aromatics Conversion via Sulfur-Tolerant Dual-Function Catalysis
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Solution Overview
Problem
Current benzene management strategies in refineries are cumbersome and costly, and there is a lack of affordable technology to convert benzene to higher alkylated aromatics in the presence of impurities like sulfur and nitrogen, leading to significant losses in Research Octane Number (RON) and potential aromatic concentration exceedance in gasoline pools.
Innovation Solution
A process that integrates benzene conversion into hydrocarbon feed streams using a dual-functional catalyst with acidic and hydrogenation-dehydrogenation functions, allowing for the direct conversion of benzene to higher alkylated aromatics while simultaneously performing hydrodesulfurization, without prior treatment for sulfur removal, using a fixed bed reactor with specific operating conditions and catalyst composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If benzene is removed or restricted from gasoline pool through fractionation, hydrogenation, or process severity reduction, then benzene content is reduced, but Research Octane Number (RON) is significantly lost
Solution Approach 1:
The patent combines benzene conversion function with existing reforming or hydrocracking units by introducing an alkylating agent (ethylene, propylene, or butylene) into the hydrocarbon feed stream. The dual-functional catalyst (zeolite support with metal dispersion) simultaneously performs benzene alkylation and hydrocracking/reforming functions, converting benzene to high-RON alkylated aromatics (toluene, xylenes) while maintaining overall gasoline quality
Solution Approach 2:
The patent changes the chemical transformation parameter from benzene removal/saturation to benzene conversion. By using a dual-functional catalyst system with specific metal dispersion (0.1-10% by weight) on zeolite support, the process transforms benzene molecules into higher alkylated aromatics, changing the molecular composition while maintaining aromatic content and improving RON
2Productivity
If conventional catalysts are used for benzene conversion, then benzene can be converted, but the process requires prior sulfur removal and is costly
Solution Approach 1:
The dual-functional catalyst serves multiple purposes simultaneously: it acts as a benzene alkylation catalyst, a hydrocracking catalyst, and a sulfur-tolerant catalyst. The metal dispersion (Ni, Co, Mo, or W) on zeolite support provides both acidic sites for alkylation and metal sites for hydrocracking, eliminating the need for separate sulfur removal units and simplifying the overall process
Solution Approach 2:
The patent uses readily available alkylating agents (ethylene, propylene, butylene) that can be obtained from refinery gas streams or petrochemical units. These inexpensive feedstocks are converted in-situ, avoiding the need for expensive purified reagents or complex purification trains, making the process economically viable
3Object-affected harmful factors
If benzene is converted to alkylated aromatics, then benzene content is reduced and petrochemical production is enhanced, but aromatic concentration in gasoline pool may exceed limits
Solution Approach 1:
The patent selectively converts benzene molecules while preserving other aromatic components. The dual-functional catalyst provides shape-selective zeolite pores that favor benzene alkylation over other reactions, and the metal dispersion promotes selective hydrocracking. This local selectivity ensures benzene is converted to alkylated aromatics while maintaining overall aromatic concentration within gasoline specifications
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 effectively reduces benzene content to ≤1 vol% while maintaining or increasing RON, accommodating impurities, and can be integrated into existing refinery processes, enhancing petrochemical production efficiency.
Implementation Method 1
converting benzene to its derivatives or alkylating it to toluene, ethylbenzene, xylenes, etc.
Implementation Method 2
simultaneous hydrodesulfurization and benzene conversion
Implementation Method 3
routing hydrocarbon feed streams with alkylating agent, sulfiding agent, and hydrogen gas to a fixed bed catalytic reactor to pass over the catalyst
Data Source
AI summary
A process for the upgrading of hydrocarbon streams, i.e., processing any hydrocarbon feed streams rich in benzene and sulphur compounds. The process for simultaneous hydrodesulfurization and benzene conversion to higher alkylated aromatic molecules (C7 to C10 aromatics), without need of prior treatment like distillation, or sulfur removal. The hydrocarbon feed streams are processed over sulfided metal catalyst impregnated on acid support simultaneously desulfurizes and alkylates the benzene molecules.