Gluconic Acid CIP Cleaner for Stainless Steel Corrosion

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Solution Overview

Problem

Current highly alkaline cleaning compositions used in clean-in-place (CIP) applications for stainless steel surfaces often lead to corrosion and staining, especially when combined with oxidizing agents like hydrogen peroxide, and fail to provide effective corrosion inhibition in both liquid and vapor phases, resulting in inefficiencies and increased energy costs due to soil buildup on heat exchange surfaces.

Innovation Solution

The use of gluconic acid or its salts in combination with an alkali metal hydroxide and a catalyst capable of decomposing active oxygen sources, such as iron sulfate, in a highly alkaline cleaning composition, which prevents corrosion and staining by maintaining a pH of at least 12, facilitating effective soil removal in both liquid and vapor phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If highly alkaline cleaning compositions are used to remove soil from heat exchange surfaces, then cleaning effectiveness is improved, but corrosion and staining of stainless steel surfaces occurs

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidcorrosion and staining
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

Gluconic acid acts as an intermediary substance that mediates between the highly alkaline cleaning composition and the stainless steel surface. It forms a protective complex with metal ions at the surface, preventing direct contact between the aggressive alkaline environment and the metal, thereby eliminating corrosion and staining while preserving cleaning effectiveness

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical parameter composition of the cleaning solution by adding gluconic acid to the highly alkaline environment. This creates a new chemical environment that maintains high pH for cleaning effectiveness while introducing chelating properties that protect the metal surface, resolving the contradiction between cleaning power and surface protection

Inventive Principle:
Principle #35Parameter changes

2Reliability

If inorganic phosphates are used as corrosion inhibitors, then corrosion protection is improved, but scale formation occurs

Engineering Contradiction:
Improvecorrosion protectionVSAvoidscale formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention replaces persistent inorganic phosphates with gluconic acid, which provides corrosion protection through reversible chelation. The gluconic acid forms soluble complexes with metal ions that prevent corrosion without creating insoluble scale deposits, offering a temporary but effective protection mechanism that avoids long-term scaling problems

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the chemical nature of the corrosion inhibitor from inorganic phosphates to organic gluconic acid. This parameter change transforms the mechanism of protection from precipitation-based to chelation-based, eliminating scale formation while maintaining corrosion inhibition effectiveness

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If equipment is shut down for complete cleaning, then thorough soil removal is achieved, but production time is lost

Engineering Contradiction:
Improvethoroughness of cleaningVSAvoidproduction downtime
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The cleaning composition is applied in advance during continuous operation, allowing the gluconic acid to establish protective complexes on surfaces before heavy soil buildup occurs. This preliminary protective action enables effective cleaning without requiring complete equipment shutdown, reducing production time loss while maintaining thorough cleaning capability

Inventive Principle:
Principle #10Preliminary action

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 gluconic acid-based composition effectively inhibits corrosion and staining on stainless steel surfaces, enhancing the efficiency of CIP processes by maintaining surface integrity and reducing energy consumption through improved soil removal and prevention of thermal degradation.

Implementation Method 1

The present invention employs the use of gluconic acid / sodium gluconate or salts thereof as a corrosion and stain inhibitor... Applicants have found, surprisingly that the gluconic acid as a corrosion inhibitor in a highly alkaline and oxidizing environment prevents corrosion and staining

Methodology Applied
Scientific EffectChelation:

Implementation Method 2

The compositions include a corrosion inhibitor and catalyst to provide surface cleaning and protection from caustic and peroxide staining and corrosion

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP4047110A1CIP method for cleaning using a non-staining high alkaline cleaner
Publication Date: 2022.08.24 ECOLAB USA INC
  • EP4047110A1 patent drawingFigure 1
  • EP4047110A1 patent drawingFigure 2
  • EP4047110A1 patent drawingFigure 3

AI summary

A method of inhibiting liquid and vapor phase corrosion and staining while cleaning soils from industrial equipment using a CIP process under highly alkaline and oxidizing conditions, whereby gluconic acid or salts thereof serve as corrosion and stain inhibitor.