FCC Gasoline Benzene Reduction via Alkylation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for reducing benzene in gasoline often result in lower research octane number (RON) and require separate catalyst systems, failing to effectively integrate with Fluid Catalytic Cracking (FCC) processes while also not valorizing FCC off-gases into liquid fuels.
Innovation Solution
An integrated process that contacts benzene-rich gasoline fractions with light olefin-rich streams in a fluidized bed alkylation reactor using a catalyst system containing ZSM-5 and Y-type Zeolite, which reduces benzene content and increases RON, utilizing the FCC regenerator as a catalyst cooler/heat sink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If benzene is removed from gasoline fraction, then benzene content is reduced, but gasoline volume and octane are lost
Solution Approach 1:
The patent converts the harmful benzene component into a useful product by alkylating it with light olefins to produce high-octane alkylbenzenes. Instead of simply removing benzene (which would lose gasoline volume), the process transforms benzene into a valuable gasoline blendstock with higher octane number, thus converting a harmful substance into a beneficial product that meets both environmental requirements and gasoline volume needs
2Object-affected harmful factors
If separate alkylation catalyst systems are used for benzene reduction, then benzene is removed, but process complexity increases and integration with FCC is lost
Solution Approach 1:
The patent merges the alkylation catalyst system with the existing FCC catalyst system by introducing ZSM-5 zeolite into the FCC unit. This integration allows the same catalyst to perform both FCC cracking and benzene alkylation functions, eliminating the need for separate catalyst systems and reducing overall process complexity while maintaining effective benzene removal
Solution Approach 2:
The FCC catalyst system with ZSM-5 additive performs multiple functions: it conducts the primary FCC cracking reaction and simultaneously catalyzes the alkylation of benzene with light olefins. This multi-functionality eliminates the need for separate dedicated alkylation catalyst systems and enables seamless integration within the existing FCC process framework
3Quantity of substance
If FCC off gas is not valorized, then simple processing is maintained, but valuable light olefins are wasted
Solution Approach 1:
The patent treats FCC off-gas, which was previously considered a waste stream to be simply burned or flared, as a valuable feedstock. By routing the off-gas containing light olefins back to the FCC reactor, the process converts this waste stream into useful alkylbenzene products, thereby eliminating waste while increasing liquid fuel production
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
Simultaneously reduces benzene content by 30-50% and increases RON, valorizes FCC off-gases into liquid fuels, and lowers FCC regenerator dense bed temperature, enhancing overall FCC unit conversion without the need for additional catalyst systems or downstream facilities.
Implementation Method 1
contacting benzene rich gasoline fraction with light olefin rich stream in a fluidized bed alkylation reactor with ZSM-5 containing FCC catalyst to produce alkyl aromatics
Implementation Method 2
contacting benzene rich gasoline fraction with light olefin rich stream in a fluidized bed alkylation reactor
Implementation Method 3
utilizing the FCC regenerator as a catalyst cooler/heat sink
Data Source
AI summary
The present invention relates to an integrated process for increasing the research octane number (RON) of FCC gasoline with simultaneous reduction in benzene content. In this process, benzene rich gasoline fraction is reacted with light olefin rich gaseous streams like FCC off gas/dry gas, coker off gas to produce alkyl aromatics using FCC catalyst system containing ZSM-5 zeolite. The catalyst is continuously drawn from the FCC regenerator by suitably placing the alkylation reactor in communication with the FCC regenerator. The product stream of the alkylation reactor is routed to main fractionator for separation of off gas and benzene lean gasoline. This integrated process not only improves the octane number of gasoline but also lowers the gasoline benzene content. Further the integrated alkylation reactor system acts as a heat sink lowering the FCC regenerator temperature and enables the FCC unit to process high CCR feeds.