Chlorine Dioxide Production via Gas-Liquid Separation

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Solution Overview

Problem

Existing small-scale chlorine dioxide production processes produce chlorine dioxide with excess acid and salt by-products, making it difficult to obtain the gas phase or aqueous solution without these by-products.

Innovation Solution

A process involving continuous reaction of alkali metal chlorate with acid and a reducing agent, followed by separation in a gas-liquid separator to extract chlorine dioxide as a gas phase, with the liquid phase being recirculated as motive fluid to minimize equipment usage and recover chlorine dioxide for further use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If small-scale chlorine dioxide production processes are used, then equipment complexity is reduced, but the product contains excess acid and salt by-products

Engineering Contradiction:
Improveprocess equipmentVSAvoidacid and salt by-products
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and separates the harmful by-products (acid and salt) from the chlorine dioxide product through a gas-liquid separator. The process divides the reaction mixture into gaseous chlorine dioxide and liquid phase containing the by-products, allowing the desired product to be obtained in a cleaner form while removing the harmful components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the production process into distinct stages: reaction zone, separation zone, and recirculation zone. By dividing the continuous process into functional segments, it achieves both simplified equipment requirements and effective removal of by-products, resolving the contradiction between equipment simplicity and product purity.

Inventive Principle:
Principle #1Segmentation

2Productivity

If large-scale chlorine dioxide production processes are used, then manufacturing efficiency is improved, but equipment complexity increases

Engineering Contradiction:
Improveproduction efficiencyVSAvoidprocess equipment
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention creates a multi-functional integrated system where a single reactor-with-separator design performs both reaction and separation functions. This universal approach maintains high production efficiency while avoiding the need for separate, complex large-scale equipment trains, thus achieving productivity without proportional increases in equipment complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the reaction vessel and gas-liquid separator into an integrated system. By combining functions that would traditionally require separate pieces of equipment, it achieves large-scale production efficiency while minimizing the overall equipment footprint and complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Object-generated harmful factors

If chlorine dioxide is withdrawn as gas from reaction medium, then product purity is improved, but equipment complexity increases

Engineering Contradiction:
Improveby-product removalVSAvoidprocess equipment
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The invention introduces a gas-liquid separator as an intermediary device between the reactor and product collection. This mediator efficiently separates gaseous chlorine dioxide from the liquid reaction medium containing by-products, achieving high product purity through a single, relatively simple separation unit rather than complex multi-stage purification systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 process efficiently separates chlorine dioxide, allowing for its use in applications like bleaching and water treatment while reducing the need for extensive equipment and minimizing by-product impact, with a high conversion rate of alkali metal chlorate to chlorine dioxide.

Implementation Method 1

bringing the product stream from the reactor to an eductor and mixing it with motive fluid fed to the eductor and thereby forming a diluted product stream

Methodology Applied
Scientific EffectFluid mixing:

Implementation Method 2

bringing the diluted product stream to a gas-liquid separator where gas is separated from liquid therein

Methodology Applied
Scientific EffectGas-liquid separation:

Implementation Method 3

further comprising the step of recirculating at least a portion of the liquid phase withdrawn from the gas-liquid separator and feeding it to the eductor as motive fluid

Methodology Applied
Scientific EffectFluid recirculation:

Implementation Method 4

reacting the alkali metal chlorate with the acid and the reducing agent to form a product stream comprising chlorine dioxide and alkali metal salt of the acid

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP1945566B1Process for production of chlorine dioxide
Publication Date: 2019.11.20 AKZO NOBEL PULP & PERFORMANCE CHEM
  • EP1945566B1 patent drawingFigure 1

AI summary

The present invention relates to a process for the production of chlorine dioxide, said process comprising the steps of continuously: (a) feeding to a reactor (1) an acid, alkali metal chlorate and a reducing agent; (b) reacting the alkali metal chlorate with the acid and the reducing agent to form a product stream (2) comprising chlorine dioxide and alkali metal salt of the acid; (c) bringing the product stream from the reactor to an eductor (3) and mixing it with motive fluid fed (4) to the eductor and thereby forming a diluted product stream (5) ; (d) bringing the diluted product stream to a gas-liquid separator (6) where gas is separated from liquid therein; (e) withdrawing a gaseous product stream (7) comprising chlorine dioxide and inert gas from said gas-liquid separator; and, (f) withdrawing a liquid phase from the gas-liquid separator. The invention also relates to a production unit to produce chlorine dioxide.