Catalyst Additive Composition for FCC Olefin Yield
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Solution Overview
Problem
Current Fluid Catalytic Cracking (FCC) processes face limitations in producing high-value olefins like propylene and LPG while suppressing undesired coke and dry gas production, despite the use of various catalyst combinations.
Innovation Solution
A catalyst additive composition comprising 10-40 wt% calcined clay, 10-40 wt% diluent clay, 10-30 wt% silica, and 1-30 wt% alumina, with specific surface area, pore diameter, and acidity levels, generated in situ to enhance olefin production and reduce coke formation during cracking of heavy hydrocarbons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional FCC catalyst combinations are used to maximize olefin production, then propylene and LPG yields increase, but coke and dry gas production also increase
Solution Approach 1:
The catalyst composition employs different zeolite components with specific pore sizes and acidity levels tailored for different functions: ZSM-5 (5.4-5.5Å pores) for propylene selectivity, Y-zeolite (13.5Å pores) for gasoline production, and the additive system for controlling coke formation. This local differentiation of catalytic properties across different crystal structures enables selective enhancement of olefins while suppressing unwanted byproducts.
Solution Approach 2:
The invention uses a composite catalyst system combining multiple zeolite types (ZSM-5, Y-zeolite) with a specific additive composition containing silica (10-30 wt%), alumina (1-30 wt%), and clay (10-40 wt%). This composite structure creates synergistic effects where each component contributes specific properties: ZSM-5 for propylene, Y-zeolite for gasoline, and the silica-alumina-clay additive for coke suppression and hydrothermal stability.
2Quantity of substance
If Faujasite zeolite with large pore openings is used to maximize gasoline production, then gasoline yield increases, but selectivity towards LPG and propylene is limited
Solution Approach 1:
The catalyst system is segmented into distinct functional components: Y-zeolite (13.5Å pores) dedicated to gasoline production, ZSM-5 (5.4-5.5Å pores) dedicated to propylene and LPG formation, and the silica-alumina-clay additive for structural support and coke control. This segmentation allows each component to optimize its specific function without interfering with others, achieving multi-product selectivity.
Solution Approach 2:
Different regions of the catalyst system have different pore sizes and acidity characteristics: Y-zeolite provides large pores for gasoline-range molecules, ZSM-5 provides medium pores for propylene selectivity, and the additive provides controlled porosity for hydrothermal stability. This local quality differentiation enables the catalyst to produce multiple products with high selectivity simultaneously.
3Productivity
If high acidity zeolite is used to enhance cracking activity, then conversion increases, but catalyst deactivation and coke formation are accelerated
Solution Approach 1:
The silica-alumina-clay additive acts as an intermediary between the high-acidity zeolite active sites and the feedstock. It provides a buffered acidity environment that maintains cracking activity while reducing excessive coke formation. The additive's controlled porosity and composition moderate the interaction between reactants and catalyst, preventing rapid deactivation.
Solution Approach 2:
The invention optimizes the acidity parameter by controlling the silica-to-alumina ratio in the additive (10-30 wt% silica, 1-30 wt% alumina) and adjusting the clay content (10-40 wt%). This parameter optimization balances cracking activity with hydrothermal stability, maintaining high conversion while extending catalyst life and reducing coke formation.
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 catalyst additive significantly increases LPG and gasoline yields while reducing coke and dry gas production, improving the overall efficiency of the FCC process.
Implementation Method 1
A catalyst additive composition suitable for fluid cracking, riser cracking and fixed bed cracking with reduction in bottom and coke, wherein the aluminosilicate and silica-alumina is generated in situ from added clay and silica
Data Source
Figure 1
AI summary
The present invention relates to a catalyst additive composition suitable for fluid cracking, riser cracking and fixed bed cracking with reduction in bottom and coke, wherein the aluminosilicate and silica-alumina is generated in situ from added clay and silica. The present invention is also directed towards the preparation of the said catalyst additive composition. The invention also discloses a process for cracking of heavy hydrocarbons using the said catalyst additive.