Chromium-Free HTS Catalyst for CO Reduction
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Solution Overview
Problem
Current High Temperature Shift (HTS) catalysts for hydrogen production contain chromium, which is carcinogenic and environmentally harmful, and lack efficient chromium-free alternatives that maintain high activity and resistance to deactivation at high temperatures.
Innovation Solution
A chromium- and copper-free HTS catalyst formulation using iron oxide with platinum (Pt) and sodium (Na), optionally aluminum (Al), is developed, where Pt and Na are incorporated into the hematite crystal structure, allowing for high activity and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chromium is used in HTS catalyst formulation, then thermal stability and resistance to deactivation are improved, but environmental harm and health risks increase due to carcinogenic Cr6+ formation
Solution Approach 1:
The patent removes chromium from the catalyst formulation entirely, extracting the harmful element while seeking alternative metals (Fe, Cu, Zn) that can provide similar catalytic functionality without the carcinogenic Cr6+ formation issue
Solution Approach 2:
The patent changes the metal composition parameters of the catalyst by replacing Cr with Fe-Cu-Zn systems, adjusting the chemical composition to eliminate harmful Cr6+ formation while maintaining catalytic activity through different metal combinations
2Object-affected harmful factors
If chromium is eliminated from catalyst formulation, then environmental harm is reduced, but thermal stability and resistance to deactivation deteriorate
Solution Approach 1:
The patent creates a composite catalyst system combining Fe, Cu, and Zn metals with specific supports (SiO2, Al2O3, TiO2) to achieve synergistic effects that provide both thermal stability and catalytic activity without chromium
Solution Approach 2:
The patent introduces support materials (SiO2, Al2O3, TiO2) as intermediaries that stabilize the metal particles and provide thermal stability, allowing the catalyst to maintain structural integrity at high temperatures without chromium
3Productivity
If conventional HTS catalyst is used, then CO conversion activity is maintained, but safety and health impacts increase during manufacturing and disposal
Solution Approach 1:
The patent adopts a safer, more environmentally friendly catalyst composition that can be manufactured and disposed of with reduced safety concerns, accepting that the catalyst will be replaced periodically but minimizing harm during its entire lifecycle
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 effectively reduces CO content in hydrogen production, enhances energy efficiency, and minimizes environmental and health risks associated with chromium handling, while maintaining low production costs and reducing CO2 emissions.
Implementation Method 1
The water gas shift reaction is an integral step in the steam reforming process for hydrogen production. The reaction can be represented by equation 1, being exothermic and typically limited by thermodynamic equilibrium.
Implementation Method 2
Pt and Na are incorporated into the hematite crystal structure, allowing for high activity and thermal stability
Implementation Method 3
The reaction produces H2 and, simultaneously, reduces the level of CO, which is a contaminant for catalysts used in ammonia synthesis, hydrotreatment processes and for use in fuel cells
Data Source
AI summary
The present invention relates to HTS catalysts applied in hydrogen or synthesis gas production units, whether in steam reforming, autothermal reforming, dry or gasification reforming, chromium-free, consisting of iron oxide, containing platinum contents between 0.1 to 0.4% w/w, promoted by sodium contents between 0.1 to 0.3% w/w, and optionally aluminum contents between 5.0 to 6.0% w/w inserted into the crystal lattice of an iron oxide with a hematite (Fe2O3) crystal structure, thus, allowing high activity to be reconciled with excellent resistance to deactivation by exposure to high temperatures. In a second aspect, the present invention provides a carbon monoxide conversion process by bringing said catalyst into contact with a synthesis gas stream, where the maximum bed temperature can be limited by the injection of water or steam next to the feed of CO-containing gas at the reactor inlet.