Sorbent Coating Method for Mercury Removal
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Solution Overview
Problem
Existing copper sorbents used for removing heavy metals from fluid streams, such as mercury and arsenic, face challenges in maintaining physical properties like attrition for more demanding applications, necessitating an improvement in their formulation to enhance their effectiveness.
Innovation Solution
A method involving the formation of sorbent precursors by coating agglomerates of particulate support materials, specifically calcined rehydratable alumina, with a particulate sulphidable copper compound, followed by drying and sulphiding to create a copper sulphide-coated sorbent, which improves the sorbent's physical properties and mercury removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional copper sorbents are used to remove heavy metals from fluid streams, then mercury removal capability is achieved, but physical properties like attrition resistance deteriorate in demanding applications
Solution Approach 1:
The invention uses a composite structure consisting of an inert particulate support material core coated with a copper compound layer. The support material provides mechanical strength and attrition resistance, while the copper compound layer provides mercury removal capability. This composite structure resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The invention applies different materials to different parts of the sorbent structure: the core uses inert support material for mechanical stability, while the outer coating uses copper compound for chemical activity. This local differentiation allows each region to optimize its function without compromising the other.
2Strength
If copper content in sorbent is reduced to improve physical properties, then attrition resistance improves, but mercury capture capability may deteriorate
Solution Approach 1:
The composite structure allows the bulk of the sorbent to be composed of strong, attrition-resistant support material, while a thin outer layer contains the copper compounds needed for mercury capture. This distributes the copper content efficiently, maintaining capture capability while improving overall mechanical strength.
Solution Approach 2:
The inert particulate support material provides a porous structure with high surface area, allowing efficient dispersion of the copper compound coating. This increases the effectiveness of the copper layer for mercury capture while using minimal copper content, thereby maintaining capture capability with reduced overall copper concentration.
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 method results in a sorbent with enhanced strength and mercury capture capabilities, matching or exceeding conventional sorbents despite a lower copper content, effectively removing heavy metals like mercury and arsenic from fluid streams.
Implementation Method 1
The precursor was converted to a sorbent suitable for removing heavy metals from liquids or gases by applying one or more sulphur compounds to sulphide the copper compound and form CuS
Implementation Method 2
Copper sulphide containing sorbents may be used to remove heavy metals from fluid streams
Implementation Method 3
Copper sorbents are conventionally pelleted compositions or granules formed from precipitated compositions containing copper
Data Source
AI summary
A method is described for preparing a sorbent precursor comprising the steps of: (i) forming agglomerates comprising a particulate support material, (ii) coating the agglomerates with a coating mixture powder comprising a particulate sulphidable copper compound and a particulate calcined, rehydratable alumina to form a coated agglomerate, and (iii) drying the coated agglomerate to form a dried sorbent precursor. The sorbent precursor may be sulphided and used to remove heavy metals such as mercury from fluid streams.