Dual Catalyst System for Heavy Oil Hydroprocessing
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Solution Overview
Problem
Heavy oil processing in refinery operations is challenging due to rapid catalyst deactivation by metals, high sulfur and nitrogen content, and instability of upgraded products, leading to frequent catalyst replacement and formation of coke and sediment, which reduces the effectiveness of ebullated bed hydroprocessing systems.
Innovation Solution
Implementing a dual catalyst system in the ebullated bed hydroprocessing system, comprising a slurry catalyst with an average particle size of 1 to 300 μm and a particulate catalyst greater than 0.65 mm, which is introduced into the reaction zone with heavy oil feedstock in the presence of hydrogen to enhance catalytic activity and reduce coke and sediment formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-metallic colloidal catalyst is synthesized in-situ by mixing with heavy oil feedstock under sulfidation conditions, then the catalyst is formed directly in the reaction zone, but tight control of catalyst properties becomes difficult and requires carefully controlled dilution and mixing steps
Solution Approach 1:
The patent applies preliminary action by pre-forming the catalyst as a slurry with controlled properties before introducing it to the reaction zone. The slurry is prepared by mixing catalyst precursor with a carrier fluid under controlled conditions, allowing precise control of catalyst concentration, particle size distribution, and composition before the sulfidation process occurs in the reaction zone. This eliminates the need to control dilution and mixing under sulfidation conditions while still achieving tight catalyst property control.
2Productivity
If the catalyst/oil ratio is increased to improve system effectiveness, then conversion efficiency improves, but significant modifications to the system are required
Solution Approach 1:
The patent applies hydraulics by using a carrier fluid to transport the catalyst as a slurry into the reaction zone. The carrier fluid suspends the catalyst particles and delivers them to the reaction zone through fluid flow, enabling increased catalyst/oil ratio without requiring mechanical modifications to the system. The slurry injection system uses hydraulic principles to introduce high concentrations of catalyst particles into the existing ebullated bed reactor, achieving improved productivity without significant system modifications.
3Reliability
If catalyst is frequently replaced to maintain activity, then catalytic performance is maintained, but system shutdowns are required and operational continuity is reduced
Solution Approach 1:
The patent applies dynamics by implementing a dynamic catalyst replenishment system where fresh catalyst slurry is continuously or periodically injected into the reaction zone to replace deactivated catalyst. This dynamic approach maintains catalytic activity without requiring complete system shutdowns, as the ebullated bed system allows for catalyst replacement while maintaining operation. The system dynamically adjusts catalyst concentration to maintain optimal activity levels, ensuring both reliability and operational continuity.
4Productivity
If heavy oil is heated to promote conversion, then reaction rate increases, but thermal cracking occurs producing free radicals that form sediment and coke precursors
Solution Approach 1:
The patent applies the intermediary principle by introducing a slurry catalyst that acts as a mediator between the thermal energy and the heavy oil molecules. The catalyst particles suspended in the slurry provide alternative reaction pathways that promote conversion at lower temperatures or reduce the severity of thermal cracking. The slurry catalyst system mediates the energy transfer and reaction processes, reducing free radical formation and subsequent coke and sediment generation while maintaining acceptable reaction rates.
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 dual catalyst system improves the conversion of heavy oil by reducing the formation of coke and sediment, increasing the catalyst/oil ratio, and extending the catalyst life, thereby enhancing the overall efficiency and operational flexibility of the heavy oil processing system without requiring significant modifications to existing infrastructure.
Implementation Method 1
dual catalyst system improves the conversion of heavy oil by reducing the formation of coke and sediment, increasing the catalyst/oil ratio, and extending the catalyst life
Implementation Method 2
passing a reaction mixture comprising heavy oil feedstock in the presence of hydrogen and a slurry catalyst to an ebullated bed reaction zone
Data Source
AI summary
A method to upgrade heavy oil feedstock using an ebullated bed reactor and a novel catalyst system is provided. The ebullated bed reactor system includes two different catalyst with different characteristics: an expanded catalyst zone containing particulate catalyst having a particle size of greater than 0.65 mm; and a slurry catalyst having an average particle size ranging from 1 to 300 μm. The slurry catalyst is provided to the ebullated bed system containing the heavy oil feedstock, and entrained in the upflowing hydrocarbon liquid passing through the ebullated bed reaction zone. The slurry catalyst reduces the formation of sediment and coke precursors in the ebullating bed reactor system. The slurry catalyst is prepared from rework materials, which form a slurry catalyst in-situ upon mixing with the heavy oil feedstock.