Natural Gas COS Removal Catalyst for Low-Temperature Desulfurization
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Solution Overview
Problem
Existing carbonyl sulfide (COS) conversion catalysts in natural gas desulfurization processes exhibit unsatisfactory catalytic activity, poor activity stability, high reaction temperatures, and low COS conversion rates, failing to meet stringent sulfur content standards.
Innovation Solution
A catalyst comprising a carrier with specific phases of AlO(OH), χ-Al2O3, and η-Al2O3, loaded with alkali metal oxide and nickel oxide, achieving a weight ratio of 1: (2-5): (0.2-0.6), and optimized surface area and pore structure for high COS conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional COS hydrolysis catalysts are used, then the sulfur recovery process can proceed, but the COS conversion rate is low and reaction temperature is high
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by using specific ratios of potassium carbonate (2-25 wt%), calcium oxide (1-10 wt%), and magnesium oxide (1-10 wt%) on a γ-Al2O3 carrier. This compositional parameter optimization enables the catalyst to achieve high COS conversion rates at lower temperatures by modifying the active sites and catalytic pathways.
Solution Approach 2:
The patent creates a composite catalyst material combining multiple metal oxides (K2CO3, CaO, MgO) supported on γ-Al2O3. This composite structure synergistically enhances catalytic activity for COS hydrolysis while maintaining structural stability, allowing efficient conversion at reduced temperatures compared to single-component catalysts.
2Productivity
If high activity catalysts are used to meet desulfurization requirements, then sulfur content can be reduced, but the catalyst suffers from large abrasion and short service life
Solution Approach 1:
The patent employs γ-Al2O3 as a porous carrier material with high surface area and appropriate pore structure. This porous structure provides a large surface area for dispersing the active metal oxide components, enhancing catalytic activity while the robust γ-Al2O3 framework protects the active phases from mechanical abrasion, thereby extending catalyst service life.
Solution Approach 2:
The composite structure of metal oxides (K2CO3, CaO, MgO) supported on γ-Al2O3 creates a synergistic system where the alumina carrier provides mechanical strength and thermal stability, while the metal oxide components provide catalytic activity. This composite design simultaneously achieves high desulfurization efficiency and catalyst durability.
3Productivity
If titanium oxide is used as carrier to achieve COS hydrolysis, then the reaction can proceed, but preparation costs are high and catalyst abrasion is large
Solution Approach 1:
The patent replaces expensive titanium oxide carriers with cheaper alternative carriers such as γ-Al2O3, silica gel, or activated carbon. These alternative carriers provide sufficient catalytic support at lower cost, making the catalyst more economically viable while maintaining acceptable performance through optimized metal oxide composition.
Solution Approach 2:
The patent optimizes the composition parameters of the metal oxide components (K2CO3, CaO, MgO) to compensate for the lower inherent activity of the alternative carriers compared to titanium oxide. By adjusting the ratios and amounts of these active phases, the catalyst achieves comparable COS hydrolysis activity at reduced preparation costs.
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 achieves a COS conversion rate of ≥99% with a service life exceeding 8 years, significantly reducing total sulfur content in natural gas while operating at low temperatures and maintaining stability.
Implementation Method 1
the presence of carbon dioxide would impose a slightly inhibitive function on the COS hydrolysis reaction
Implementation Method 2
a separate COS hydrolysis reaction unit is generally arranged in front of the Claus Unit
Data Source
Figure 1~2
Figure 3~4
AI summary
The present disclosure relates to the technical field of desulfurization, particularly, to a catalyst and an application, and a method for removing carbonyl sulfide in natural gas. The catalyst comprises a carrier, and an alkali metal oxide and nickel oxide which are loaded on the carrier; based on the total weight of the catalyst, the content of the carrier is 90-97wt%, the content of the alkali metal oxide is 2-6wt%, and the content of the nickel oxide is 1-4wt%; at least part of the carrier is AIO(OH), χ-Al2O3 and η-Al2O3 phases. The catalyst has the advantages of high catalytic activity, good activity stability, and long service life, can achieve a COS conversion rate of greater than or equal to 99% and a service life of 8 years or above, and can effectively reduce the content of carbonyl sulfur in natural gas.