Resid FCC Catalyst Composition for Heavy-Oil Diffusion Control
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Solution Overview
Problem
Existing RFCC catalysts face challenges in efficiently converting resid oil into high-value products like gasoline and light olefins while minimizing coke and dry gas formation, due to issues such as metal deactivation, reduced thermal stability, and diffusion limitations of heavy hydrocarbons.
Innovation Solution
A RFCC catalyst composition is developed using a hierarchical matrix with high dense alumina, silica or alumina, binder grade alumina, colloidal silica, clay, and rare-earth Y zeolite, combined with desilication and biochar to enhance porosity and metal tolerance, and incorporating active components to reduce coke and dry gas yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high porosity is increased to accommodate bigger molecules of resid oil, then diffusion limitation is reduced, but catalyst structural stability may be compromised
Solution Approach 1:
The catalyst structure is segmented into hierarchical pore systems with different size ranges (micropores <2 nm, mesopores 2-50 nm, and macropores >50 nm), allowing each pore level to serve specific functions: micropores for molecular sieving and catalytic activity, mesopores for mass transport, and macropores for accommodating large resid oil molecules, thus resolving the contradiction between porosity and structural stability
Solution Approach 2:
The catalyst employs composite materials including zeolite crystals embedded in a hierarchical porous matrix composed of alumina, silica, and binder materials. This composite structure provides both the high porosity needed for molecule diffusion and the structural stability required for catalyst integrity under severe cracking conditions
2Reliability
If metal trap components are increased to handle high metal contents in resid oil, then catalyst deactivation is reduced, but catalyst activity and selectivity may be compromised
Solution Approach 1:
Metal trap components are distributed locally within the catalyst structure at specific concentrations (0.5-5 wt% rare earth oxides, 1-10 wt% metal trap additives) rather than uniformly throughout, allowing metal deactivation resistance at active sites while preserving overall catalyst activity and selectivity for gasoline production
Solution Approach 2:
Rare earth oxides and metal trap additives serve as intermediary substances that selectively bind metal contaminants (Ni, V, Na) from resid oil feed, preventing these metals from deactivating the primary catalytic sites while maintaining the catalyst's cracking activity and product selectivity
3Productivity
If zeolite content is increased to improve cracking activity, then conversion of heavy hydrocarbons is improved, but coke and dry gas formation increase
Solution Approach 1:
The catalyst optimizes zeolite content within a specific range (10-40 wt%) and adjusts zeolite crystal size (5-20 micrometers) and silica-to-alumina ratio to achieve optimal cracking activity while minimizing unwanted side reactions. The hierarchical pore structure parameters are also tuned to control product distribution and reduce coke formation
Solution Approach 2:
The hierarchical porous matrix structure with controlled pore size distribution facilitates selective diffusion of reactants and products, allowing efficient cracking of heavy hydrocarbons to gasoline-range molecules while preventing excessive cracking that leads to dry gas and coke formation through controlled mass transport
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 achieves high conversion of resid oil with reduced coke and dry gas formation, improved gasoline yield, and enhanced thermal stability, while accommodating additional metals and coke, thus overcoming diffusion limitations.
Implementation Method 1
the high porosity would diminish the diffuse limitation of bigger molecules of resid oil
Implementation Method 2
The process is carried out over the RFCC catalyst. The modern RFCC catalyst is a composite of zeolite, matrix, binder, and different additives
Implementation Method 3
the metals bind on the active site of the catalyst and block them
Implementation Method 4
the thermal stability of catalysts reduces in the presence of metals at a higher temperature
Data Source
AI summary
The present invention discloses a resid FCC (RFCC) catalyst composition and a process for preparation thereof. More particularly, the present invention discloses a catalytic cracking catalyst composition designed for the RFCC process, characterized by reduced coke, bottom cracking, and dry gas formation. The present invention also discloses a process for preparation of the catalyst composition suitable for larger molecules of resid oil, ensuring minimal coke and dry gas production during the resid oil cracking process.