Copper Oxide Sorbent Reduction Resistance via Halide Doping
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Solution Overview
Problem
Copper oxide (CuO) sorbents are easily reducible, leading to inefficiencies in removing hydrogen sulfide and other contaminants, as they reduce to copper metal at low temperatures, compromising the purity of hydrogen for fuel cell applications and causing safety concerns, and existing methods to enhance reduction resistance, such as combining with other metal oxides, increase costs and reduce surface area.
Innovation Solution
Adding a small amount of an inorganic halide, like sodium chloride, to basic copper carbonate and calcining at elevated temperatures to produce a copper oxide sorbent that is more resistant to reduction, effectively increasing its stability and performance in removing sulfur and other contaminants from gas and liquid streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CuO is used as a sorbent for removing hydrogen sulfide and contaminants, then the removal efficiency is improved, but CuO is easily reduced to Cu metal at low temperatures, compromising performance and purity
Solution Approach 1:
The patent creates a composite material by combining CuO with metal halides (such as CuCl2, FeCl3, AlCl3) to form a composite sorbent. This composite structure prevents the reduction of CuO to Cu metal while maintaining the sorbent's ability to remove hydrogen sulfide and other contaminants. The metal halides act as structural promoters that stabilize CuO at low temperatures.
Solution Approach 2:
The patent changes the chemical composition parameters of the sorbent by introducing metal halides in specific amounts (0.1-5 wt% of CuO). This parameter modification alters the reduction behavior of CuO, raising the reduction temperature and preventing reduction at operating temperatures. The specific composition ratio is optimized to achieve maximum reduction resistance.
2Stability of the object's composition
If other metal oxides are combined with CuO to retard reduction, then reduction resistance is improved, but manufacturing complexity increases and surface area decreases
Solution Approach 1:
Instead of combining CuO with multiple metal oxides (which would increase complexity), the patent changes the approach by using metal halides as the modifying component. This parameter change in the chemical composition simplifies the manufacturing process while achieving the same reduction resistance effect. The metal halides can be easily incorporated during the preparation stage without requiring complex mixed oxide formation procedures.
3Stability of the object's composition
If other metal oxides are combined with CuO to reduce reducibility, then reduction resistance is improved, but production cost increases
Solution Approach 1:
The patent uses small amounts of metal halides (which are relatively inexpensive) to modify CuO, replacing the need for expensive metal oxide combinations. The metal halides serve as cost-effective additives that provide the same reduction resistance function at lower cost. The small required amounts (0.1-5 wt%) further reduce the overall material cost.
4Area of stationary object
If CuO is reduced to Cu metal, then high dispersion of copper metal is achieved, but H2S removal efficiency decreases and safety concerns arise
Solution Approach 1:
The patent applies preliminary anti-action by preventing the reduction of CuO to Cu metal in the first place through the addition of metal halides. This preemptive measure stops the formation of Cu metal particles, thereby maintaining CuO's superior H2S removal efficiency and eliminating safety concerns associated with reduced copper metal, while still achieving the desired dispersion through the composite structure.
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 copper oxide sorbent exhibits enhanced resistance to reduction, ensuring higher purity of hydrogen and improved safety by maintaining a stable CuO form, even at elevated temperatures, effectively removing contaminants like hydrogen sulfide, arsenic, and phosphine, while maintaining a high surface area and cost-effectiveness.
Implementation Method 1
calcining for a sufficient period of time to decompose the basic copper carbonate and to produce the copper oxide sorbent
Implementation Method 2
The resulting copper oxide sorbent exhibits enhanced resistance to reduction, ensuring higher purity of hydrogen and improved safety by maintaining a stable CuO form, even at elevated temperatures, effectively removing contaminants like hydrogen sulfide, arsenic, and phosphine
Data Source
AI summary
Mixing small amounts of an inorganic halide, such as NaCl, to basic copper carbonate followed by calcination at a temperature sufficient to decompose the carbonate results in a significant improvement in resistance to reduction of the resulting copper oxide. The introduction of the halide can be also achieved during the precipitation of the carbonate precursor. These reduction resistant copper oxides can be in the form of composites with alumina and are especially useful for purification of gas or liquid streams containing hydrogen or other reducing agents.