Composite Chlorine Catalyst for Fluidized Bed Stability
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Solution Overview
Problem
Current catalysts for hydrogen chloride oxidation to produce chlorine in fluidized bed reactors face challenges such as high reaction temperatures, component loss, and agglomeration, leading to instability and high costs, which hinder industrialization.
Innovation Solution
A method involving the preparation of catalysts by mixing slurries A and B under controlled temperature and residence time, followed by spray drying and calcination, to produce catalysts with improved mechanical strength and stability, suitable for long-term use in fluidized bed reactors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If copper-based catalysts are used for hydrogen chloride oxidation, then cost is reduced, but reaction temperature must be raised to 400-450°C which causes component loss and catalyst deactivation
Solution Approach 1:
The patent uses a composite catalyst system comprising copper chloride (0.5-5 wt%), chromium chloride (0.1-2 wt%), and boron-containing compounds (0.1-2 wt%) supported on silica or alumina. This composite formulation allows the catalyst to achieve high activity at lower temperatures (300-400°C) while maintaining stability, resolving the contradiction between using cheap copper-based catalysts and preventing component loss.
Solution Approach 2:
The patent modifies the chemical composition parameters of the catalyst by introducing chromium and boron compounds alongside copper chloride. This parameter change enables the catalyst to function effectively at reduced temperatures (300-400°C instead of 400-450°C), thereby preventing thermal degradation and component volatilization while maintaining cost-effectiveness.
2Productivity
If fixed bed reactor is used for hydrogen chloride oxidation, then high conversion is achieved, but temperature runaway occurs and active components are lost by volatilization
Solution Approach 1:
The patent changes the catalyst composition parameters by incorporating chromium chloride and boron-containing compounds with copper chloride. This modification enables the catalyst to maintain high activity at lower operating temperatures (300-400°C), effectively preventing temperature runaway while achieving high chlorine conversion rates in the fluidized bed reactor.
3Ease of operation
If fluidized bed reactor is used for hydrogen chloride oxidation, then heat exchange convenience is improved, but catalyst particles agglomerate due to low melting point chloride intermediates
Solution Approach 1:
The patent employs a composite catalyst formulation with copper chloride, chromium chloride, and boron-containing compounds supported on silica or alumina. This composite structure raises the effective melting point of the active components and prevents agglomeration by stabilizing the chloride intermediates, allowing the catalyst to maintain particle integrity and fluidization characteristics during prolonged operation.
Solution Approach 2:
The patent develops a catalyst formulation that prevents agglomeration and extends catalyst life, transforming the previously short-lived agglomerating catalyst into a stable, long-lasting catalyst suitable for industrial fluidized bed operations.
4Productivity
If high reaction temperature is used to achieve high conversion on copper catalysts, then chlorine yield is improved, but catalyst deactivation occurs due to active mobility of chlorides
Solution Approach 1:
The patent modifies the catalyst composition by adding chromium chloride and boron-containing compounds to copper chloride. This parameter change enables the catalyst to achieve high chlorine conversion (80-85% per pass) at lower temperatures (300-400°C), preventing thermal deactivation and maintaining long-term stability.
Solution Approach 2:
The composite catalyst system combines copper chloride, chromium chloride, and boron-containing compounds on a silica or alumina support. This composite formulation synergistically enhances catalyst stability at operating temperatures while maintaining high activity, resolving the contradiction between productivity and reliability.
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 achieves 80-85% average per pass conversion with reduced cohesion and abrasion, extending catalyst life and maintaining flowability over 1000 hours, while minimizing costs through enhanced mechanical strength and stability.
Implementation Method 1
catalytic oxidation method (Deacon process) is the most effective solution
Implementation Method 2
treating the mixed slurry with spray drying to obtain catalyst precursor particles
Implementation Method 3
calcining the catalyst precursor particles to obtain said catalysts
Data Source
AI summary
The present invention relates to a method for preparing catalyst used for preparing chlorine by oxidizing hydrogen chloride. The method is mixing a slurry mainly containing boron and chromium with a slurry mainly containing copper, boron, alkali-metal elements, rare-earth elements, aluminum sol, silica sol, carrier and optionally other metal elements, the mixing temperature being not more than 100°C, and the residence time being not more than 120 minutes, the mixed slurry is successively treated with spray drying, high temperature calcination, so that the catalyst is obtained. The present invention also relates to the catalyst prepared through the method, use of the catalyst used in the process of preparing chlorine by oxidizing hydrogen chloride and a method for preparing chlorine by using the catalyst. The catalyst is used for preparing chlorine by oxidizing hydrogen chloride with oxygen or air in fluidized bed reactor, and has an excellent activity and anti-caking property, a relatively good mechanical strength and a relatively long service life.