Method for purifying a device used in the concentration of a mineral acid

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Solution Overview

Problem

Existing methods for cleaning devices used in mineral acid concentration processes are cumbersome, time-consuming, and often cause mechanical or chemical stress to acid-resistant materials, leading to potential damage.

Innovation Solution

A method involving rinsing devices with an aqueous alkali metal hydroxide solution of 1% to 30% concentration at 40°C to 90°C for 2 hours to 7 days, which does not require disassembly and minimizes mechanical stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If mechanical cleaning methods (disassembly and high-pressure water) are used to remove solid deposits, then cleaning effectiveness is improved, but mechanical stress damages acid-resistant materials

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidintegrity of acid-resistant materials
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces mechanical cleaning methods (disassembly and high-pressure water jets) with a chemical cleaning method using aqueous alkali metal hydroxide solutions. This substitution eliminates mechanical stress on acid-resistant materials while maintaining effective removal of solid deposits through chemical dissolution and loosening mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes changes in chemical parameters (introduction of alkali metal hydroxide solution with specific concentration ranges and temperature conditions) to alter the cleaning mechanism from mechanical to chemical. The parameters of the cleaning solution (concentration, temperature, contact time) are optimized to achieve effective cleaning without mechanical damage.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If mechanical disassembly is performed for cleaning, then access to all components is improved, but cleaning time and complexity increase

Engineering Contradiction:
Improveaccess to componentsVSAvoidcleaning time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The chemical cleaning method allows the device to remain assembled while the alkali metal hydroxide solution circulates through all components, replacing the need for mechanical disassembly. This maintains access to all components for cleaning while dramatically reducing cleaning time and operational complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If cleaning chemicals are used to avoid mechanical stress, then material integrity is improved, but material durability is reduced due to chemical exposure

Engineering Contradiction:
Improveintegrity of acid-resistant materialsVSAvoiddurability of materials
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent carefully controls the parameters of the cleaning solution (alkali metal hydroxide concentration between 1-30%, temperature between 40-90°C, and contact time between 2 hours to 7 days) to achieve effective cleaning while minimizing chemical damage. These controlled parameters balance cleaning effectiveness with material durability preservation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The alkali metal hydroxide solution acts as an intermediary cleaning agent that effectively removes deposits while being less harmful to acid-resistant materials compared to traditional mechanical methods. The solution mediates between the need for thorough cleaning and the need to preserve material integrity.

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 method effectively cleans devices without disassembly, reducing the risk of mechanical damage to acid-resistant materials and simplifying the cleaning process, thereby extending the lifespan of the equipment.

Implementation Method 1

rinsed with an aqueous alkali metal hydroxide solution with a mass concentration of alkali metal hydroxide in the range of 1% to 30% at a temperature in the range of 40 °C to 90 °C for a period of 2 hours to 7 days

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

process for concentrating a mineral acid by evaporating water

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4077213B1Method for purifying a device used in the concentration of a mineral acid
Publication Date: 2025.06.18 COVESTRO DEUTSCHLAND AG
  • EP4077213B1 patent drawingFigure 1

AI summary

The present invention relates to a method of preparing an apparatus (or a plant comprising multiple apparatuses), for example a heat exchanger, an evaporator or a distillation column, for use in a process (especially one operated continuously) for concentration of a mineral acid by evaporating water, wherein the apparatus or plant comprises (at least) one device resistant to the mineral acid and the device is rinsed with an aqueous alkali metal hydroxide solution of a concentration by mass of alkali metal hydroxide in the range from 1% to 30% at a temperature in the range from 40°C to 90°C for a period of 2 hours to 7 days.