Amine Removal from Polyether Polyol Reactors

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Solution Overview

Problem

Existing methods fail to effectively remove amine contaminants from equipment used in the production of polyether polyols, limiting the ability to switch between producing amine-initiated and non-amine initiated polyether polyols without compromising product quality in terms of alkalinity and color.

Innovation Solution

A method involving a series of chemical treatments, including contacting the equipment with an aqueous solution of a first acid, an acidic metal conditioner, and an alkali metal hydroxide, followed by discharge and recirculation, to effectively remove amine contaminants and prepare the equipment for producing non-amine initiated polyether polyols.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single reactor is used to produce both amine-initiated and non-amine initiated polyether polyols, then asset utilization is maximized, but amine contamination compromises the quality (alkalinity and color) of non-amine initiated polyether polyols

Engineering Contradiction:
Improveasset utilizationVSAvoidproduct quality (alkalinity and color)
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by implementing a multi-step cleaning protocol (acid wash, base wash, water rinse) between production runs to remove amine contaminants from the reactor before producing non-amine initiated polyether polyols. This preliminary cleaning action ensures that no amine residues remain to contaminate the next batch, thereby maintaining product quality while enabling single-reactor operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the chemical parameters of the cleaning solutions used in the intermediate cleaning step. Specifically, it uses acid wash followed by base wash, changing the pH and chemical composition parameters to effectively remove different types of contaminants. This parameter change approach ensures thorough removal of amine contaminants while preparing the reactor for the next production cycle.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If dedicated reactors are used for amine-initiated polyether polyol production, then product quality is maintained, but asset utilization decreases

Engineering Contradiction:
Improveproduct qualityVSAvoidasset utilization
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent makes the reactor universal by enabling it to produce both amine-initiated and non-amine initiated polyether polyols through effective cleaning protocols. The reactor is designed and operated to handle multiple product types sequentially, with the cleaning system ensuring that amine contaminants are removed between runs. This multi-functionality allows a single reactor to replace what would traditionally require dedicated reactors for each product type.

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

3Manufacturing precision

If intermediate cleaning steps are implemented between producing amine-initiated and non-amine initiated polyether polyols, then product quality is maintained, but process complexity increases

Engineering Contradiction:
Improveproduct qualityVSAvoidcleaning process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cleaning process uses parameter changes (pH adjustment, temperature control, solution composition) to achieve effective contaminant removal. By systematically varying these parameters through sequential wash steps, the process maintains simplicity in each individual step while achieving comprehensive cleaning overall. The standardized parameter changes make the process repeatable and manageable despite multiple steps.

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 method allows for the effective removal of amine contaminants, enabling the same reactor to produce both amine-initiated and non-amine initiated polyether polyols with desired low alkalinity and color characteristics.

Implementation Method 1

contacting the equipment with an aqueous solution of a first acid

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

contacting the equipment with an aqueous solution of a first acid

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 3

contacting the equipment with an aqueous solution of an acidic metal conditioner

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 4

contacting the equipment with an aqueous solution of an alkali metal hydroxide

Methodology Applied
Scientific EffectNeutralization reaction: Chemical Bonding

Data Source

PatentEP4056625B1Methods for removing amine contaminants from equipment used in the production of polyether polyols
Publication Date: 2025.01.29 COVESTRO LLC
  • EP4056625B1 patent drawingFigure 1

AI summary

The present disclosure describes methods of removing amine contaminants from equipment used in the production of polyether polyols. These methods include: (a) contacting the equipment with an aqueous solution of a first acid; (b) discharging the aqueous solution of the first acid from the equipment; (c) contacting the equipment with an aqueous solution of an acidic metal conditioner; (d) discharging the aqueous solution of the acidic metal conditioner from the equipment; (e) contacting the equipment with an aqueous solution of an alkali metal hydroxide; and (f) discharging the aqueous solution of the alkali metal hydroxide from the equipment.