Catalyst Pore Volume Control for Chlorine Production Stability

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Solution Overview

Problem

In industrial-scale hydrogen chloride oxidation in fixed-bed multitubular reactors, temperature variations in catalyst beds lead to unstable chlorine production due to differences in catalyst physical properties, particularly pore volume, causing hot spots and potential reaction runaway.

Innovation Solution

Selecting catalysts with specific pore volume ratios to form catalyst beds in reaction tubes, ensuring that the pore volume ratio of one production lot to another is less than 1.20, effectively suppressing temperature variations in hot spots by averaging physical properties across reaction zones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If catalysts of different production lots are used in reaction tubes, then the reactor can handle large-scale production, but temperature variation in hot spots increases leading to unstable chlorine production

Engineering Contradiction:
Improveindustrial-scale chlorine productionVSAvoidtemperature stability in catalyst beds
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention controls the pore volume parameter of catalysts within a specific range (0.18-0.22 mL/g) to minimize temperature variation in hot spots during hydrogen chloride oxidation, thereby maintaining stable chlorine production at industrial scale

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies different pore volume specifications to catalysts based on their position and function in the reaction system, optimizing local heat management in catalyst beds to prevent runaway reactions while maintaining high productivity

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If temperature control is adjusted to accommodate catalysts with higher hot spot temperatures, then runaway reactions are prevented, but conversion efficiency decreases in tubes with lower hot spots

Engineering Contradiction:
Improvereaction runaway preventionVSAvoidhydrogen chloride conversion efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

By precisely controlling the pore volume parameter of catalysts within 0.18-0.22 mL/g, the invention achieves uniform hot spot temperatures across all reaction tubes, eliminating the need for compromised temperature control settings and maintaining high conversion efficiency while preventing runaway reactions

Inventive Principle:
Principle #35Parameter changes

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

This approach stabilizes chlorine production by minimizing temperature variations in catalyst beds, ensuring consistent reaction conditions and preventing reaction runaway, thereby enhancing efficiency and safety in industrial-scale hydrogen chloride oxidation.

Implementation Method 1

a catalyst to be used in oxidation of hydrogen chloride

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

This oxidation reaction of hydrogen chloride is an exothermic reaction of 59 kJ/mol for chlorine

Methodology Applied
Scientific EffectExothermic reaction: Exothermic Reaction

Data Source

PatentUS10882026B2Process for producing chlorine
Publication Date: 2021.01.05 SUMITOMO CHEM CO LTD

AI summary

There is disclosed a process for producing chlorine by feeding hydrogen chloride and oxygen into catalyst beds which are formed in the reaction tubes of a fixed-bed multitubular reactor and which contain catalysts for use in oxidation of hydrogen chloride, and this process is characterized in that the catalyst beds in one reaction zone in the fixed-bed multitubular reactor are catalyst beds formed by packing catalysts of a plurality of production lots; and in that the catalysts of the plurality of production lots satisfy the following condition (I): Condition (I): a value of AB is smaller than 1.20 (with the proviso that A and B are values of three significant figures, having a relationship of A≥B), wherein the pore volume of a catalyst of one production lot optionally selected from the plurality of production lots is A [ml/g], and the pore volume of another one production lot is B [ml/g].