CO Shift Catalyst Phosphorus Promoter Carbon Precipitation
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Solution Overview
Problem
Existing CO shift catalysts, such as Co-Mo/Al2O3, face challenges with catalyst deterioration and reduced activity due to carbon precipitation at high temperatures, requiring excessive water vapor, which hampers power generation efficiency and CO2 emission reduction in IGCC plants.
Innovation Solution
A CO shift catalyst comprising molybdenum or iron as a main component, nickel or ruthenium as an accessory component, and phosphorus as a promoter, supported on titanium, zirconium, and cerium oxides, which reduces acid site activity and suppresses carbon precipitation even with reduced water vapor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a Co-Mo/Al2O3-based catalyst is used for CO shift reaction, then CO conversion activity is achieved at high temperature, but carbon precipitation occurs causing catalyst deterioration
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by incorporating phosphorus as a promoter and using titanium/zirconium/cerium oxides as carriers instead of conventional alumina. This compositional modification alters the catalyst's properties to suppress carbon precipitation while maintaining CO conversion activity, directly resolving the contradiction between productivity and reliability
Solution Approach 2:
The patent creates a composite catalyst material combining multiple metal oxides (molybdenum/iron, nickel/ruthenium, phosphorus) supported on a composite carrier of titanium/zirconium/cerium oxides. This composite structure synergistically provides both high-temperature CO conversion activity and resistance to carbon precipitation, simultaneously achieving improved productivity and reliability
2Reliability
If excessive water vapor is added to prevent carbon precipitation, then catalyst durability is improved, but power generation efficiency decreases due to reduced water vapor extraction from HRSG
Solution Approach 1:
The patent changes the water vapor to CO ratio parameter from the conventional excessive amount (H2O/CO ≥ 3) to a reduced amount (H2O/CO = 0.5 to 2.0). The modified catalyst composition enables stable operation at these lower water vapor ratios, improving power generation efficiency by reducing water vapor extraction from HRSG while maintaining catalyst durability through the phosphorus promoter and oxide carrier
3Loss of energy
If water vapor addition ratio is reduced from H2O/CO = 3 to H2O/CO = 1, then power generation efficiency is improved, but CO shift conversion becomes unstable and catalyst deteriorates rapidly
Solution Approach 1:
The patent optimizes the water vapor addition ratio parameter to a specific range (H2O/CO = 0.5 to 2.0) and combines it with modified catalyst composition (phosphorus promoter, titanium/zirconium/cerium oxide carrier). This coordinated parameter change enables stable CO shift conversion even at reduced water vapor ratios, achieving both improved energy efficiency and maintained reliability
Solution Approach 2:
The patent effectively extends the catalyst's operational life under reduced water vapor conditions by incorporating phosphorus as a protective promoter that prevents carbon precipitation. This modification makes the catalyst more robust and durable, allowing stable operation with reduced water vapor supply that would otherwise cause rapid catalyst deterioration
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 stable and efficient CO conversion over a long period with reduced water vapor, enhancing power generation efficiency and durability, while minimizing carbon precipitation and acid site activity.
Implementation Method 1
conversion into CO2 through the following reaction by using a shift catalyst while adding water vapor (H2O) is suggested (Patent Literature 2). CO + H2O ⇔ CO2 + H2 + 40.9 kJ/mol (exothermic reaction)
Implementation Method 2
A CO shift catalyst comprising molybdenum or iron as a main component, nickel or ruthenium as an accessory component, and phosphorus as a promoter, supported on titanium, zirconium, and cerium oxides, which reduces acid site activity and suppresses carbon precipitation
Data Source
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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); a promoter component containing either calcium (Ca), potassium (K), sodium (Na), phosphor - us (P), or magnesium (Mg); and a support that supports the active component and the promoter component. Said support consists of one or more of the following: an oxide of titanium (Ti); an oxide of zirconium (Zr); and an oxide of cerium (Ce).