CO Shift Catalyst Composite Oxide Carrier
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Solution Overview
Problem
Conventional CO shift catalysts, such as Co-Mo/Al2O3-based catalysts, face challenges with carbon precipitation at high temperatures, requiring excessive water vapor to maintain activity, which is inefficient and reduces power generation efficiency in IGCC plants, necessitating a catalyst that can operate stably with reduced water vapor.
Innovation Solution
A CO shift catalyst with a composite oxide carrier, including TiO2-SiO2, TiO2-La2O3, or other composite oxides, which increases the specific surface area, allowing stable CO conversion even with a low water vapor supply, reducing catalyst deterioration and maintaining activity over a long period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a Co-Mo/Al2O3-based catalyst is used to perform CO shift reaction, then CO conversion activity is achieved, but carbon precipitation occurs at high temperatures requiring excessive water vapor addition
Solution Approach 1:
The patent uses a composite oxide carrier consisting of TiO2 and SiO2 (or other oxides like Al2O3, ZrO2, CeO2, La2O3) instead of a single oxide carrier. This composite structure provides both high surface area for catalytic activity and resistance to carbon precipitation, resolving the contradiction between maintaining CO conversion activity and preventing carbon deposition at high temperatures.
Solution Approach 2:
The patent changes the chemical composition parameters of the carrier from conventional single oxides to specific composite oxide ratios (TiO2-SiO2 or combinations with other oxides). This parameter change enables the carrier to maintain structural stability and resist carbon precipitation while providing sufficient active surface area for CO conversion, eliminating the need for excessive water vapor addition.
2Reliability
If an excessive amount of water vapor is added to prevent carbon precipitation, then catalyst durability is improved, but power generation efficiency decreases due to water vapor extraction from HRSG
Solution Approach 1:
The composite oxide carrier (TiO2-SiO2 or TiO2 combined with Al2O3, ZrO2, CeO2, or La2O3) inherently resists carbon precipitation through its chemical and structural properties. This eliminates the need to add excessive water vapor for protection, thereby maintaining catalyst durability while avoiding the energy loss associated with water vapor extraction from the heat recovery steam generator.
Solution Approach 2:
The patent converts the potential harm of carbon precipitation into a benefit by using the composite oxide carrier's inherent resistance to carbon deposition. The carrier's composition is designed to actively prevent carbon accumulation, transforming what would be a harmful effect into a protective feature that maintains catalyst activity without requiring additional water vapor.
3Loss of energy
If water vapor supply is reduced to improve power generation efficiency, then energy loss is decreased, but catalyst activity deteriorates due to carbon precipitation
Solution Approach 1:
The composite oxide carrier provides inherent resistance to carbon precipitation, allowing the CO shift reaction to proceed stably even with reduced water vapor supply. This enables the system to reduce water vapor extraction from the HRSG (improving energy efficiency) while maintaining catalyst activity and reaction stability through the carrier's protective properties.
Solution Approach 2:
The patent changes the carrier composition parameters to create a material that is inherently resistant to carbon deposition. This parameter change allows the system to operate with lower water vapor ratios without suffering from catalyst deactivation due to carbon precipitation, thereby maintaining productivity while reducing energy 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
The catalyst maintains high initial CO conversion ratios and durability even with a significant reduction in water vapor, enhancing the efficiency and stability of the CO shift reaction, thereby improving power generation efficiency and reducing water vapor extraction in IGCC plants.
Implementation Method 1
a carrier which carries the active component and includes a composite oxide
Implementation Method 2
CO + H 2 O ⇔ CO 2 + H 2 + 40.9 kJ/mol (exothermic reaction)
Implementation Method 3
CO + H 2 O ⇔ CO 2 + H 2 + 40.9 kJ/mol (exothermic reaction)
Data Source
Figure 1
Figure 2
AI summary
This CO shift catalyst, which reforms carbon monoxide (CO) present in a gas, comprises the following: an active component containing a primary component, namely either molybdenum (Mo) or iron (Fe), and a secondary component, namely either nickel (Ni) or ruthenium (Ru); and a complex-oxide support that supports the active component. Said complex-oxide support comprises two or more of the following: titanium (Ti), zirconium (Zr), cerium (Ce), silicon (Si), aluminum (Al), and lanthanum (La).