Secondary Reactor for Residual CO Conversion

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Solution Overview

Problem

Conventional processes for producing acetic acid from carbon monoxide suffer from inefficiencies, particularly in the recovery and utilization of residual carbon monoxide, leading to waste and reduced overall conversion efficiency.

Innovation Solution

A process involving the reaction of residual carbon monoxide with methanol or methanol derivatives over a metal catalyst in a secondary reactor, such as a trickle bed or fixed bed reactor, to produce additional acetic acid, thereby enhancing the overall conversion of carbon monoxide and reducing waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional methanol carbonylation processes are used with venting of off-gas to control carbon monoxide partial pressure, then catalyst activity and stability are maximized, but residual carbon monoxide is wasted and overall conversion efficiency is reduced

Engineering Contradiction:
Improvecatalyst activity and stabilityVSAvoidresidual carbon monoxide
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent recovers residual carbon monoxide from the off-gas stream by directing it to a secondary reactor where it is reacted with methanol to form additional acetic acid. This replaces the conventional approach of venting or flaring the residual CO, thereby recovering a valuable reactant that would otherwise be wasted.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The patent extends the useful action by introducing a secondary reactor that continuously converts residual carbon monoxide into additional acetic acid product. This ensures that no carbon monoxide is lost in the venting process, maintaining continuous productivity and maximizing reactant utilization.

Inventive Principle:
Principle #20Continuity of useful action

2Manufacturing precision

If off-gas is purged or flared after recovery units to remove non-condensable gases, then purification is achieved, but carbon monoxide reactants are lost

Engineering Contradiction:
Improvepurification qualityVSAvoidcarbon monoxide reactants
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent converts the harmful waste of residual carbon monoxide into a beneficial resource by directing it to a secondary reactor where it is converted into additional acetic acid product. This transforms what would be wasted reactants into valuable production material.

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

Solution Approach 2:

Instead of discarding residual carbon monoxide through purging or flaring, the patent recovers it by directing it through recovery units and into a secondary reactor, where it is converted into additional acetic acid product.

Inventive Principle:
Principle #34Discarding and recovering

3Productivity

If a secondary reactor is introduced to react residual carbon monoxide, then overall conversion efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveoverall conversion efficiencyVSAvoidreactor system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The secondary reactor is designed to handle multiple functions: it receives residual carbon monoxide from the off-gas stream, reacts it with methanol to form additional acetic acid, and integrates with the existing recovery units. This multi-functional approach maximizes productivity while managing system complexity.

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

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 approach significantly increases the overall carbon monoxide conversion efficiency, reducing the amount of carbon monoxide purged or flared and improving the production of acetic acid by utilizing residual carbon monoxide in derivative streams.

Implementation Method 1

reacting at least a portion of the residual carbon monoxide with at least one of methanol and a methanol derivative over a metal catalyst, preferably a solid catalyst, optionally comprising at least one metal selected from the group consisting of rhodium, iridium, ruthenium, nickel, and cobalt

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

separating the crude acetic acid product comprising flashing the crude acetic acid product into a first vapor stream comprising acetic acid and residual carbon monoxide

Methodology Applied
Scientific EffectFlash evaporation: Flash Evaporation

Data Source

PatentEP2621881B1Production of acetic acid with high conversion rate
Publication Date: 2020.03.25 CELANESE INTERNATIONAL CORP
  • EP2621881B1 patent drawingFigure 1
  • EP2621881B1 patent drawingFigure 2
  • EP2621881B1 patent drawingFigure 3

AI summary

A process for producing acetic acid comprising the steps of reacting carbon monoxide and at least one of methanol and a methanol derivative in a first reactor under conditions effective to produce a crude acetic acid product; separating the crude acetic acid product into at least one derivative stream, at least one of the at least one derivative stream comprising residual carbon monoxide; and reacting at least a portion of the residual carbon monoxide with at least one of methanol and a methanol derivative over a metal catalyst in a second reactor to produce additional acetic acid.