Filter Regeneration for Acrylic Acid Production

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Solution Overview

Problem

Filters used in the production of acrylic acid become contaminated with metal oxides during regeneration, leading to a deterioration in the color tone and metal content of purified acrylic acid, resulting in off-specification products and increased production costs.

Innovation Solution

A method for regenerating filters involves washing with an aqueous alkaline solution to remove adhered polymers, followed by water flushing to remove residual alkaline substances, and then contacting the filter with purified acrylic acid for regeneration, which helps in removing metal oxides and maintaining the quality of the filtered product.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the filter is washed with aqueous sodium hydroxide solution to remove acrylic acid polymer, then the polymer removal efficiency is improved, but metal oxides remain on the filter causing deterioration of product quality

Engineering Contradiction:
Improvepolymer removal efficiencyVSAvoidmetal oxide contamination
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The regeneration process is divided into multiple sequential steps: water washing to remove water-soluble substances, alkaline washing to remove polymer, and a new acid washing step to remove metal oxides. Each step targets specific contaminants, achieving comprehensive cleaning without mutual interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a new parameter (acidic environment) to the regeneration process by using dilute nitric acid washing. This parameter change enables the removal of metal oxides that cannot be removed by alkaline washing alone, while the acid concentration is carefully controlled to prevent filter damage.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the filter is regenerated using only water and alkaline solution washing, then the operation simplicity is maintained, but the metal oxide contamination persists affecting product color tone

Engineering Contradiction:
Improveregeneration operation simplicityVSAvoidproduct color tone quality
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The regeneration process is divided into multiple sequential steps: water washing to remove water-soluble substances, alkaline washing to remove polymer, and a new acid washing step to remove metal oxides. Each step targets specific contaminants, achieving comprehensive cleaning without mutual interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Dilute nitric acid is introduced as an intermediary substance in the regeneration process. It acts as a mediator that selectively removes metal oxides from the filter without damaging the filter structure or interfering with the previously performed water and alkaline washing steps.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If the filter is contacted with purified acrylic acid for regeneration, then the metal oxide removal is improved, but the contact time and production cycle are extended

Engineering Contradiction:
Improvemetal oxide removal efficiencyVSAvoidproduction cycle time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

Purified acrylic acid is used to regenerate the filter, and the same purified acrylic acid subsequently passes through the regenerated filter. The acrylic acid serves dual purposes: as a regenerating agent and as the product to be filtered, eliminating the need for separate regeneration and production cycles.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The regeneration process and the filtration process are merged into a unified operation. The purified acrylic acid that would normally only be filtered is instead first used to regenerate the filter and then immediately passed through the regenerated filter, combining two functions into one continuous process.

Inventive Principle:
Principle #5Merging (Combining)

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 prevents the deterioration of the color tone and metal content of purified acrylic acid, reducing the quantity of off-specification products and lowering production costs by ensuring efficient filter regeneration.

Implementation Method 1

washing with an aqueous alkaline solution to remove adhered polymers

Methodology Applied
Scientific EffectChemical dissolution: Solvation

Implementation Method 2

followed by water flushing to remove residual alkaline substances

Methodology Applied
Scientific EffectPhysical washing: Fluid Spray

Implementation Method 3

contacting the filter with purified acrylic acid for regeneration, which helps in removing metal oxides

Methodology Applied
Scientific EffectChemical dissolution: Solvation

Data Source

PatentEP2394732B1Method for regenerating filter
Publication Date: 2021.03.31 NIPPON SHOKUBAI CO LTD

AI summary

[PROBLEM] There is provided a method for regenerating a filter, by which deterioration of the color tone of purified acrylic acid can be prevented. [SOLUTION] There is provided a method for regenerating a filter which has been used in a filtration step in the process for producing an acrylic acid, comprising a step (A) wherein the filter is washed with an aqueous alkaline solution, a step (B) wherein the filter is washed with water after the step (A), and a step (C) wherein the filter is brought into contact with the acrylic acid for regeneration for at least one hour after the step (B).