Eggshell Catalyst Nickel Oxide Surface Layer Methanation
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Solution Overview
Problem
Existing metal aluminate-supported catalysts in methanation and steam reforming processes face challenges in achieving uniform dispersion of nickel oxide, leading to suboptimal catalyst activity and increased greenhouse gas emissions.
Innovation Solution
The development of an eggshell catalyst with nickel oxide concentrated as a surface layer on a calcined metal aluminate support, achieved by impregnating the support with a nickel acetate solution at elevated temperatures and calcining, which enhances catalyst activity while minimizing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel oxide is uniformly dispersed within the catalyst support, then metal surface area is maximized, but catalyst activity is suboptimal due to non-optimal distribution
Solution Approach 1:
The patent applies local quality by creating an eggshell catalyst where nickel oxide is concentrated in an outer layer (0-1000μm thickness) on the support surface rather than being uniformly distributed. This localized concentration in the eggshell layer provides optimal catalyst activity while the underlying support maintains structural integrity, resolving the contradiction between surface area and catalytic performance.
2Manufacturing precision
If impregnation is used to achieve uniform dispersion, then metal oxide distribution is improved, but nitrogen oxide emissions increase due to conventional impregnation methods
Solution Approach 1:
The patent changes the chemical parameter of the impregnation process by using nickel acetate instead of conventional nickel nitrate. This parameter change achieves the desired eggshell distribution pattern while eliminating nitrogen oxide emissions, as acetate decomposition does not produce NOx. The solution simultaneously improves metal oxide distribution control and eliminates harmful emissions.
3Object-generated harmful factors
If metal loadings are reduced to minimize emissions, then environmental performance is improved, but catalyst strength decreases
Solution Approach 1:
The patent segments the catalyst structure into two distinct zones: an eggshell layer containing the nickel oxide catalyst (0-1000μm) and an underlying support structure. This segmentation allows the metal loading to be concentrated in the thin outer layer, minimizing overall metal content and emissions, while the bulk support provides the necessary mechanical strength and structural stability.
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
This approach results in improved catalyst activity with reduced metal loadings, minimized nitrogen oxide emissions, and increased catalyst strength, offering commercial benefits and enhanced performance in steam reforming and methanation processes.
Implementation Method 1
impregnating a calcined support comprising a metal aluminate with a solution comprising nickel acetate
Implementation Method 2
drying the impregnated support, (ii) calcining the dried impregnated support, to form nickel oxide on the surface of the support
Implementation Method 3
the reduction of the nickel oxide to the active elemental nickel carried out in-situ
Data Source
Figure 1
AI summary
An eggshell catalyst is described, comprising nickel oxide supported on a calcined support comprising a metal aluminate, wherein the calcined support is in the form of a shaped pellet, extrudate or granule having a length, width and height in the range 3-50 mm and wherein the nickel oxide is not uniformly distributed within the catalyst support but is concentrated at the surface as a layer of thickness ≤ 1000µm.