Adsorbent Particles with Colloidal Silica Binder for High Crush Strength
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Solution Overview
Problem
Existing adsorbents for gas separation in PSA and VPSA processes face challenges in achieving high mass transfer rates and crush strength while maintaining consistency and avoiding particle matting and inhomogeneity, which limits their efficiency and productivity.
Innovation Solution
The development of adsorbent particles with a binder content of 15 wt% or less, characterized by high crush strengths and size-compensated relative rate/porosity values, using colloidal silica binders and specific manufacturing processes such as extrusion-marumerization to create homogeneous and porous particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If binder content is increased to strengthen adsorbent particles, then crush strength is improved, but mass transfer rate deteriorates due to increased density
Solution Approach 1:
The patent applies parameter changes by precisely controlling binder content (5-15 wt%), pore size (0.03-0.5 mm), and particle size (0.5-3.0 mm) to achieve optimal balance between crush strength and mass transfer rate. The specific parameter ranges are designed to maintain structural integrity while preserving porosity for efficient mass transfer.
Solution Approach 2:
The patent uses composite materials combining adsorbent particles with controlled amounts of binder (silica, alumina, or clay) to create a heterogeneous structure. This composite approach allows the binder to provide mechanical strength while the adsorbent matrix maintains high porosity and mass transfer capability.
2Productivity
If particle size is reduced to improve mass transfer rate, then productivity is improved, but crush strength deteriorates due to weaker particles
Solution Approach 1:
The patent optimizes particle size parameters to 0.5-3.0 mm range with controlled binder content (5-15 wt%) to achieve the desired balance. This parameter optimization ensures particles are small enough for high mass transfer rates but large enough to maintain structural strength.
Solution Approach 2:
The patent creates composite particles with binder-adsorbent structures that provide internal support. The binder forms a matrix that reinforces the particle structure, allowing smaller particles to maintain adequate crush strength while preserving high surface area and porosity for efficient mass transfer.
3Stability of the object's composition
If binder content is increased to prevent particle collapse, then structural stability is improved, but porosity deteriorates resulting in poor mass transfer
Solution Approach 1:
The patent precisely controls binder content parameters at 5-15 wt% to maintain the optimal balance. This parameter control ensures sufficient binder to prevent collapse during handling and operation, while leaving enough void space for porosity to remain high for effective mass transfer.
Solution Approach 2:
The patent creates local quality variations within particles through controlled binder distribution. The binder is present in sufficient amounts to provide structural support at critical locations, while maintaining high porosity in the adsorbent matrix regions where mass transfer occurs.
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 resulting adsorbent particles exhibit high mass transfer rates and crush strengths, enhancing the efficiency and productivity of gas separation processes while minimizing the risk of particle attrition and fluidization.
Implementation Method 1
In PSA and VPSA processes, compressed air is pumped through a fixed bed of an adsorbent exhibiting an adsorptive preference for one of the main constituents whereby an effluent product stream enhanced in the non-adsorbed (or lesser adsorbed) constituent is obtained
Implementation Method 2
it is possible to shorten cycle time by reducing particle size of adsorbent aggregates. This recognition has been based upon the assumption that the time needed for adsorbates to travel through the macropores of the agglomerated adsorbent particles limits the adsorption/desorption cycle time, i.e., macropore diffusion is the rate limiting step in adsorption processes
Data Source
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AI summary
High rate and high crush-strength adsorbent particles and collections of such particles, and particularly LiLSX particles, are provided. A binder is employed in the form of a colloidal solution during the method of manufacture. Suitable binders include various silica binders. The particles are made using the steps of mixing, agglomeration, calcination and in the case of certain adsorbents such as LiX and LiLSX, ion exchange and activation. When the adsorption rate is expressed in the form SCRR/∈p (mmol mm2/g s), desirable collections of adsorbent particles can have values of at least 4.0 for the highly-exchanged Li (at least 90% Li exchanged) form of the collection of particles and can further be characterized by particles having average crush strengths of at least 0.9 lbf for particles having an average diameter of at least about 1.0 mm.