FCC Additive Composition for Gasoline Octane and Yield
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Solution Overview
Problem
Conventional ZSM-5 additives used in fluid catalytic cracking (FCC) operations increase gasoline octane but result in significant gasoline yield loss, as they crack gasoline range molecules into lighter olefins, thereby reducing overall gasoline yield.
Innovation Solution
A customized additive composition incorporating medium pore pentasil zeolites with variable SiO2/Al2O3 mole ratios, combined with kaolin clay, alumina, phosphate, and bivalent metals from Group-IIA or Group-IB, which enhances gasoline octane without appreciable cracking, thereby minimizing yield loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ZSM-5 additives are used to enhance gasoline octane, then gasoline octane increases, but gasoline yield decreases due to cracking of gasoline range molecules into lighter olefins
Solution Approach 1:
The patent modifies the SiO2/Al2O3 mole ratio parameter of ZSM-5 zeolite from conventional values to specifically 18-35, and controls crystal size at 0.5-5.0 microns. These parameter changes optimize the catalyst's selectivity to enhance octane through aromatic formation rather than cracking, thereby improving octane while preserving gasoline yield
Solution Approach 2:
The patent creates a composite additive system combining modified ZSM-5 zeolite with a matrix containing alumina, silica, and phosphate. This composite structure allows the ZSM-5 component to selectively enhance octane while the matrix provides structural support and controls overall cracking activity, resolving the contradiction between octane enhancement and yield preservation
2Measurement precision
If ZSM-5 additives crack gasoline range molecules to increase octane, then gasoline octane improves, but lighter olefin yield increases at the expense of gasoline
Solution Approach 1:
By optimizing the SiO2/Al2O3 ratio to 18-35 and crystal size to 0.5-5.0 microns, the patent changes the reaction pathway selectivity of ZSM-5. This causes the catalyst to favor aromatic formation (which increases octane) over cracking to lighter olefins, thereby improving octane while minimizing gasoline loss
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 additive increases gasoline octane by 2-3 units with minimal loss, improving light olefin and aromatics selectivity while maintaining gasoline yield, outperforming conventional ZSM-5 additives.
Implementation Method 1
Catalytic cracking catalyst includes a ZSM-5 type catalytic component contacted in the reaction zone with metal containing hydrocarbon feedstock. The hydrocarbon feedstock is cracked at high temperature by cracking catalyst resulting in increased gasoline octane
Implementation Method 2
said additive further comprises bivalent metal selected from Group-IIA or Group-IB in an amount of 0.1 to 5.0 wt. %
Data Source
AI summary
This invention relates to an additive capable of increasing the gasoline octane (by 2-3 units) with minimum loss of gasoline. More specifically, the present invention discloses a fluid catalytic cracking additive composition capable of enhancing gasoline octane, said composition comprising 5-50 wt. % zeolite component, 0-15 wt % alumina, 5-20 wt % colloidal silica, 10-60 wt % kaolin clay, 5-15 wt % phosphate, and 0.1 to 5.0 wt. % of bivalent metal selected from Group-IIA or Group-IB, wherein the zeolite component comprises of medium pore pentasil zeolite in an amount of 1 to 50 wt. % and said zeolite consists of one or more MFI topology zeolite having SiO2/Al2O3 mole ratio in the range of 10-280. The present invention also discloses a process for preparation of the additive.