Staged Catalyst System for Selective Hydrogenation
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Solution Overview
Problem
Current methods for selective hydrogenation of aromatic fractions suffer from high aromatic loss and low durability of catalysts, leading to inefficiencies and increased costs due to frequent catalyst replacement and solid waste generation.
Innovation Solution
A multi-stage catalyst system is employed, comprising a first catalyst bed with inorganic oxide support and active metals like Ni, Pd, Pt, Ru, Re, Co, Mo, or Ni-Mo, and a second catalyst bed with Ni-Mo or Ni-W, arranged in a staged loading configuration to minimize aromatic loss while maintaining long-term hydrogenation activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single hydrogenation catalyst is used, then the removal of unsaturated hydrocarbons is achieved, but aromatic loss increases and catalyst durability decreases
Solution Approach 1:
The catalyst system is divided into multiple catalyst beds with different catalyst types (e.g., Ni-Mo in reduced form for high activity, Co-Mo in sulfide form for selectivity) arranged in sequence. Each catalyst bed performs a specific function in the hydrogenation process, allowing the system to achieve high unsaturated hydrocarbon removal while minimizing aromatic loss and maintaining long-term durability.
Solution Approach 2:
The invention uses composite catalyst systems combining different metal components (Ni, Co, Mo) in different chemical forms (reduced metals, sulfides) on appropriate supports. This composite approach leverages the complementary strengths of each catalyst component to achieve both high activity for unsaturated hydrocarbon removal and high selectivity to preserve aromatics.
2Productivity
If clay treatment is used to remove olefins, then the process is widely commercialized, but clay deactivates quickly causing frequent replacement and waste generation
Solution Approach 1:
The invention changes the chemical form and composition parameters of the catalyst from traditional clay to hydrogenation catalysts with specific metal compositions (Ni-Mo, Co-Mo) in controlled chemical states (reduced or sulfide forms). This parameter change enables both high olefin removal efficiency and extended catalyst lifetime without frequent replacement.
3Manufacturing precision
If selective hydrogenation is performed to remove unsaturated hydrocarbons, then the bromine index is reduced, but aromatic loss occurs
Solution Approach 1:
Different catalyst beds are assigned different local qualities (chemical compositions and states) to perform specific functions. For example, Co-Mo in sulfide form provides high selectivity for unsaturated hydrocarbon hydrogenation, while Ni-Mo in reduced form provides high activity. This local differentiation allows the system to achieve high selectivity for unsaturated hydrocarbon removal while minimizing aromatic 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
This approach effectively reduces unsaturated hydrocarbons by at least 30% with less than 1% aromatic loss, enhancing the durability and efficiency of the hydrogenation process.
Implementation Method 1
Process for Reducing Unsaturated Hydrocarbons in Aromatic Fraction Through Selective Hydrogenation
Implementation Method 2
configuring a catalyst bed through staged loading of a plurality of hydrogenation catalysts with different catalytic properties
Data Source
AI summary
Disclosed are a process and system that are capable of performing selective hydrogenation on aromatic fractions by configuring a catalyst bed through staged loading of a plurality of hydrogenation catalysts with different catalytic properties, or configuring a catalyst system in which a plurality of hydrogenation catalysts are arranged using a plurality of reactors in such a way as to be equivalent with the staged loading, and as a result, are capable of suppressing aromatic loss while improving the selective removal of unsaturated hydrocarbons in the aromatic fraction and durability compared to the case of using a single catalyst.