Zeolitic Adsorbent Composition Resisting COS Formation
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Solution Overview
Problem
Conventional zeolites promote the formation of COS during gas purification processes, especially when treating gas mixtures containing H2S and CO2, leading to undesirable side reactions and reduced adsorption capacity under acidic and hot conditions, necessitating frequent replacement of adsorbents.
Innovation Solution
A zeolitic composition comprising a combination of A, X, Y, and chabazite zeolites, along with clinoptilolite, which are agglomerated without additional clay binders, providing enhanced resistance to acidic conditions and minimizing COS formation by optimizing zeolite ratios and particle sizes for improved water and H2S/CO2 adsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional zeolites (especially sodium-exchanged types) are used to remove H2S and water from gas mixtures, then adsorption capacity for H2S and water is improved, but COS formation is promoted due to catalytic effects and thermodynamic shift
Solution Approach 1:
The patent changes the chemical composition parameters of the zeolite by controlling the cation exchange process to achieve specific sodium content thresholds (greater than 60% for X zeolite and greater than 40% for A zeolite). This parameter optimization allows the zeolite to maintain high adsorption capacity while reducing catalytic promotion of COS formation, resolving the contradiction between adsorption performance and harmful byproduct generation
Solution Approach 2:
The patent creates a composite zeolitic material by combining zeolite crystals with a specific binder system. The binder content is controlled to be between 5-20% by weight, forming a composite structure that maintains the zeolite's adsorption properties while minimizing unwanted catalytic activity. This composite approach allows simultaneous achievement of high H2S/water removal and low COS formation
2Productivity
If high sodium content zeolites are used to enhance H2S adsorption, then adsorption efficiency is improved, but COS formation is significantly promoted
Solution Approach 1:
The patent establishes specific parameter ranges for sodium content in the zeolite structure: greater than 60% sodium exchange for X zeolite and greater than 40% for A zeolite. These optimized parameters maximize H2S adsorption capacity while minimizing the catalytic promotion of COS formation, effectively resolving the productivity-harmful factors contradiction
3Productivity
If zeolites are used in acidic and hot conditions (>250°C) for gas dehydration, then water removal is achieved, but hydrothermal degradation and mechanical deterioration occur rapidly
Solution Approach 1:
The patent develops a composite material consisting of zeolite crystals bound with a specific binder formulation containing 5-20% binder by weight. This composite structure provides mechanical strength and structural stability that resists hydrothermal degradation and mechanical deterioration under severe conditions (>250°C, acidic environment), while maintaining high water adsorption capacity. The binder acts as a protective matrix that enhances reliability without sacrificing productivity
Solution Approach 2:
The patent applies different properties to different parts of the adsorbent material: the zeolite crystals provide high water adsorption capacity in the active sites, while the binder matrix provides structural stability and resistance to hydrothermal degradation in the bulk material. This local differentiation of properties allows simultaneous achievement of high productivity and reliability under severe operating conditions
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 zeolitic composition effectively adsorbs water and H2S/CO2 while significantly reducing COS formation, maintaining higher adsorption capacity and mechanical strength under severe conditions, thus extending the lifespan of adsorbents and preventing reprocessing of liquefied propane.
Implementation Method 1
The use of zeolites, also called molecular sieves, is a common practice in gas purification methods, particularly for selectively removing molecules such as water or H2S. These molecules are thereby adsorbed on these porous solids.
Implementation Method 2
The use of zeolites, also called molecular sieves, is a common practice in gas purification methods, particularly for selectively removing molecules such as water or H2S. These molecules are thereby adsorbed on these porous solids.
Implementation Method 3
The use of zeolites, also called molecular sieves, is a common practice in gas purification methods, particularly for selectively removing molecules such as water or H2S.
Data Source
AI summary
The present invention relates to zeolitic compositions of at least one A, X, Y zeolite and/or chabazite and at least one clinoptilolite type of zeolite.These zeolitic compositions can be used in adsorption methods for removing H2O and/or CO2 and/or H2S present in gas or liquid mixtures, particularly for purifying natural gas, acid gases, alcohols and mercaptans.