Copper Boron Rare Earth Catalyst for HCl Oxidation
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Solution Overview
Problem
Current catalysts for the catalytic oxidation of hydrogen chloride to produce chlorine face challenges such as high economic costs, environmental pollution, and instability, particularly with copper-based catalysts that suffer from copper ingredient loss at higher temperatures, limiting their activity and lifespan.
Innovation Solution
A catalyst comprising 1-20 wt% copper, 0.01-5 wt% boron, 0.1-10 wt% alkali metal elements, and 0.1-15 wt% rare earth or alkaline earth elements, supported on materials like molecular sieve or kaolin, prepared through a two-step impregnation and calcination process, enhancing stability and activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper-based catalysts are used for hydrogen chloride oxidation, then catalytic activity is achieved, but copper ingredient loss occurs at higher temperatures reducing stability
Solution Approach 1:
The patent applies composite materials by combining copper with rare earth metals (lanthanum, cerium, praseodymium, neodymium, or samarium) to create a composite catalyst system. This composite structure prevents copper loss at high temperatures while maintaining catalytic activity, directly resolving the contradiction between achieving catalytic function and preventing material degradation.
Solution Approach 2:
The rare earth metals act as intermediary substances that stabilize the copper component during high-temperature operation. These intermediary elements prevent direct copper loss to the environment while allowing the copper to maintain its catalytic function, effectively mediating between the need for active copper and the need to prevent its loss.
2Productivity
If traditional catalytic oxidation methods are used, then chlorine production is achieved, but economic cost and environmental pollution remain high
Solution Approach 1:
The patent employs relatively inexpensive rare earth metals and copper compounds that can be used in moderate quantities without requiring expensive precious metal catalysts. This approach achieves effective chlorine production while reducing both economic cost and environmental burden associated with precious metal extraction and disposal.
Solution Approach 2:
The patent optimizes operational parameters including temperature (320-460°C), pressure (0.1-0.6 MPa), and hydrogen chloride to oxygen mole ratio (0.5-9:1) to maximize chlorine yield while minimizing harmful byproducts. These parameter adjustments enable high productivity with reduced environmental impact.
3Productivity
If copper-based catalysts operate at higher temperatures to increase reaction rate, then productivity improves, but copper loss increases reducing catalyst lifespan
Solution Approach 1:
The composite catalyst system of copper combined with rare earth metals enables operation at higher temperatures (320-460°C) without excessive copper loss. The rare earth components stabilize the structure at elevated temperatures, allowing sustained high reaction rates throughout the catalyst's operational life, thus extending catalyst lifespan while maintaining productivity.
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 new catalyst offers improved stability and activity, increasing chlorine yield by 1%-5% compared to existing copper-based catalysts, while being cost-effective and environmentally friendly, with reduced copper loss and lower operational costs.
Implementation Method 1
The oxidation of hydrogen chloride by oxygen or air as an oxidant to prepare chlorine is a good route. This reaction is represented by the following stoichiometric formula: 2HCl+1⁄2O2↔Cl2+H2O−57.7 kJ/mol
Data Source
AI summary
The present invention relates to a catalyst for producing chlorine by oxidation of hydrogen chloride and a method for preparing the same. The catalyst comprises a support and active ingredients that comprise 1-20 wt % of copper, 0.01-5 wt % of boron, 0.1-10 wt % of alkali metal element(s), 0.1-15 wt % of one or more rare earth elements, and 0-10 wt % of one or more elements selected from magnesium, calcium, barium, manganese, iron, nickel, cobalt, zinc, ruthenium or titanium based on the total weight of the catalyst. The catalyst is prepared by a two-step impregnation method. Comparing with the available catalysts of the same type, the catalyst according to the present invention has greatly improved conversion and stability.