Phosphoric Acid Purification via Combustion Chamber and Gas-Acid Contactor

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Solution Overview

Problem

Industrial and agro-industrial waste solutions containing phosphorus, particularly orthophosphate and polyphosphate species, are difficult to recycle due to the presence of undesirable volatilizable materials like fluorine, sulfur, and carbon, making it impossible to produce high-value purified phosphoric or polyphosphoric acid.

Innovation Solution

A process involving a gas-acid contactor and combustion chamber where an aqueous feed solution and recirculated enriched phosphoric acid are contacted with combustion gases to enrich the phosphoric acid concentration, followed by spraying the enriched solution into a combustion chamber to evaporate water and oxidize impurities, producing a purified phosphoric acid solution with reduced volatilizable materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If waste solutions containing phosphorus and undesirable volatile matter are treated as simple waste, then environmental pollution is reduced, but resource value is lost and high-value phosphoric acid cannot be produced

Engineering Contradiction:
Improveresource valueVSAvoidundesirable volatile matter
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies this principle by converting the harmful undesirable volatile matter into beneficial combustion gases that serve dual purposes: they provide heat for evaporation and create a reactive atmosphere for in-situ oxidation of phosphorus species. The volatile matter that previously made the solution unusable is now transformed into a useful energy and chemical resource for the purification process

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical and physical parameters of the waste solution by introducing combustion gases that alter the oxidation state and concentration of phosphorus species. The temperature, oxygen content, and chemical composition parameters are modified to convert low-value waste into high-value phosphoric acid product

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If traditional evaporation methods are used to concentrate phosphoric acid, then water is removed and concentration increases, but energy consumption is high

Engineering Contradiction:
Improvephosphoric acid concentrationVSAvoidenergy consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent implements self-service by using the undesirable volatile matter present in the waste solution itself as the fuel source for evaporation. The volatile compounds combust to generate heat that directly drives the water evaporation and concentration process, eliminating the need for external energy inputs and significantly reducing energy consumption

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent merges multiple functions into a single combustion process: evaporation of water, concentration of phosphoric acid, oxidation of phosphorus species, and destruction of volatile matter all occur simultaneously in the combustion chamber, improving efficiency and reducing energy requirements compared to separate processing steps

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If combustion is used to remove volatile matter, then purification is achieved, but combustion gases require complex management before atmospheric release

Engineering Contradiction:
Improvepurification qualityVSAvoidcombustion gas management
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by designing the combustion chamber to simultaneously perform purification, concentration, oxidation, and energy generation. The combustion gases produced are not treated as waste requiring separate management but are reused as the heating medium for evaporation, simplifying the overall system and reducing the complexity of gas management infrastructure

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

Solution Approach 2:

The combustion gases act as an intermediary substance that transfers energy from the combustion of volatile matter to the evaporation of water. Instead of directly releasing combustion gases into the atmosphere, the system uses them as a heat carrier to achieve purification and concentration, thereby simplifying emission management while maintaining high purification quality

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 effectively purifies phosphoric acid solutions, increasing their concentration while reducing energy consumption and improving combustion gas management, enabling the production of high-value phosphoric acid from previously unusable waste solutions.

Implementation Method 1

spraying the enriched solution into a combustion chamber to evaporate water

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

spraying the enriched solution into a combustion chamber

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

oxidize impurities

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 4

spraying the enriched solution into a combustion chamber

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 5

an aqueous feed solution and recirculated enriched phosphoric acid are contacted with combustion gases to enrich the phosphoric acid concentration

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3774650B1Method for recycling residual solutions comprising phosphorus and device for such a method
Publication Date: 2023.08.16 PRAYON SA
  • EP3774650B1 patent drawingFigure 1~2
  • EP3774650B1 patent drawingFigure 3
  • EP3774650B1 patent drawingFigure 4~5

AI summary

The invention relates to a method and device for the purification of phosphoric acid contained in a residual solution comprising undesirable volatilizable materials. The residual solution is mixed with a solution of enriched phosphoric acid and is sprayed into a flame of a combustion chamber in order to form a combustion solution P3 of phosphoric acid purified of the undesirable volatilizable materials. The combustion gases resulting from the combustion chamber are contacted with a feed solution in a gas-acid contactor in order to increase the temperature and concentration of P2O5 and thus to form the solution of enriched phosphoric acid. A portion of this solution is conveyed at a flow rate Qp into the combustion chamber. The remainder of the solution is conveyed into a recycle loop in order to be reintroduced into the gas/acid contactor at a flow rate Q2. The ratio of the flow rates, Qp / (Qp + Q2) is controlled at a predefined value.