Copper embedded polyurethane foam for mercury removal
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Solution Overview
Problem
Current copper-based adsorbents for mercury removal in natural gas purification suffer from reduced porosity and structural integrity issues, leading to diffusion limitations and mechanical failure due to liquid carryover, resulting in inefficient mercury removal and high pressure drops.
Innovation Solution
A polyurethane foam-based adsorbent with dispersed metal compounds, such as copper sulfide, is used to enhance porosity and structural integrity, allowing for better contaminant access and increased active site utilization, while being resistant to moisture and liquid carryover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional alumina-based adsorbents with micro to nano porosity are used, then structural strength is maintained, but porosity is reduced leading to diffusion limitations and egg-shell formation
Solution Approach 1:
The patent uses polyurethane foam as the base material, which inherently possesses a macro-porous structure with high porosity (up to 90%). This foam structure provides large internal surface area and excellent mass transfer characteristics, eliminating the egg-shell effect while maintaining structural integrity through the foam's cellular architecture.
Solution Approach 2:
The patent creates a composite material by impregnating polyurethane foam with copper-based active sites (such as copper sulfide or copper-exchanged zeolite). This composite structure combines the mechanical strength and porosity benefits of foam with the mercury adsorption capability of copper compounds, resolving the contradiction between strength and porosity.
2Productivity
If copper-based adsorbents are used for mercury removal, then mercury removal capacity is improved, but structural integrity is lost after liquid carryover
Solution Approach 1:
The polyurethane foam-copper composite structure provides both high mercury removal capacity through copper active sites and excellent structural integrity through the foam matrix. The foam structure resists mechanical failure during liquid carryover while the dispersed copper compounds maintain high accessibility and activity for mercury adsorption.
Solution Approach 2:
The copper-based active sites are dispersed throughout the three-dimensional foam structure rather than concentrated on the outer surface. This local distribution ensures that active sites throughout the entire adsorbent volume remain accessible and functional, preventing the egg-shell effect and maintaining reliability under varying operating conditions.
3Ease of manufacture
If adsorbent porosity is reduced due to poring limitation, then manufacturing simplicity is maintained, but mass transfer zone is reduced leading to poor metal utilization
Solution Approach 1:
The patent leverages the inherent macro-porous structure of polyurethane foam, which is formed through a well-established foam expansion process. This approach maintains manufacturing simplicity while achieving superior porosity and mass transfer characteristics compared to traditional sintered or extruded adsorbents, thereby improving metal utilization throughout the adsorbent bed.
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 adsorbent achieves improved mercury removal capacity and stability, with enhanced mass transfer and reduced adsorbent weight, maintaining performance under challenging conditions.
Implementation Method 1
copper sulfide, which acts as a scavenger for mercury
Implementation Method 2
The presence of macro pores in the foam sample would mitigate the resistance issue of mercury and other contaminants and thus, the formation of the 'egg-shell.'
Data Source
AI summary
Adsorbents for removing contaminants from hydrocarbon streams are described. The adsorbents comprise polyurethane foam comprising a metal compound. The polyurethane foam can be rigid or flexible and has a structure comprising a combination of open cells and closed cells. Methods of removing contaminants from hydrocarbon streams using the adsorbent are also described.