CO2 Recovery Oxygen Reduction via Catalytic Removal

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Solution Overview

Problem

Conventional CO2 recovery methods face issues with residual oxygen in the recovered CO2 gas, leading to equipment clogging, pipe corrosion, and colored chemical products due to high oxygen concentrations, which require additional energy and costs for reduction.

Innovation Solution

A CO2 recovery apparatus incorporating an oxygen reducing apparatus with a combustion catalyst, such as Pd-based or Pt-based metal catalyst, and a hydrogen-rich gas supply to reduce oxygen levels in the CO2 gas, arranged between compressors and coolers to efficiently decrease oxygen concentrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional CO2 recovery methods are used, then CO2 can be recovered from flue gas, but residual oxygen in the recovered CO2 gas causes equipment clogging, pipe corrosion, and product coloring

Engineering Contradiction:
Improveequipment reliabilityVSAvoidoxygen concentration in CO2 gas
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes oxygen from the recovered CO2 gas stream using a dedicated oxygen removal unit positioned between the regenerator and compressor. This separation approach isolates the harmful oxygen component from the CO2 product, preventing it from causing equipment clogging, corrosion, and product coloring issues downstream

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary oxygen removal unit that acts as a mediator between the regenerator and compressor. This unit contains catalysts or chemical agents that selectively react with and remove oxygen from the CO2 gas stream, protecting downstream equipment from oxygen-related damage without affecting the CO2 recovery process

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If additional oxygen reduction measures are implemented, then oxygen concentration can be reduced, but energy consumption and operational costs increase

Engineering Contradiction:
Improveoxygen concentration in CO2 gasVSAvoidenergy consumption for oxygen reduction
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent changes the chemical parameters of the CO2 gas stream by introducing catalysts or chemical agents in the oxygen removal unit that selectively react with oxygen at specific temperature and pressure conditions. This allows for efficient oxygen removal through chemical transformation rather than energy-intensive physical separation methods

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The oxygen removal unit is designed to operate using the existing thermal energy from the regenerator outlet gas, eliminating the need for additional external energy input. The system utilizes the heat already present in the process stream to drive the oxygen removal reaction, making the process self-sufficient and energy-efficient

Inventive Principle:
Principle #25Self-service

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

Effectively reduces oxygen concentration in the CO2 gas from several hundred parts per million to less than tens of parts per million, mitigating issues like equipment clogging and product coloring, while optimizing energy usage and reducing operational costs.

Implementation Method 1

A CO2 recovery apparatus incorporating an oxygen reducing apparatus with a combustion catalyst, such as Pd-based or Pt-based metal catalyst

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

a combustion catalyst that reduces O2 in the CO2 gas

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

a CO2 absorber that brings flue gas containing CO2 into contact with CO2 absorbing liquid to reduce CO2 in the flue gas

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 4

a regenerator that reduces CO2 in rich solvent that has absorbed CO2 in the CO2 absorber

Methodology Applied
Scientific EffectDesorption: Desorption

Implementation Method 5

The regenerator 15 reduces CO2 in the CO2 absorbing liquid 14

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 6

at least two compressors that compress CO2 gas released from the regenerator

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 7

a second cooler that is arranged downstream of the second compressor and upstream of the second separator

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP2223731B1CO2 recovery apparatus and CO2 recovery method
Publication Date: 2014.05.14 MITSUBISHI HEAVY IND LTD
  • EP2223731B1 patent drawingFigure 1
  • EP2223731B1 patent drawingFigure 2
  • EP2223731B1 patent drawingFigure 3

AI summary

A CO2 recovery apparatus according to a first embodiment of the present invention includes: a CO2 absorber (13) that brings flue gas containing CO2 into contact with CO2 absorbing liquid to reduce CO2 in the flue gas; a regenerator (15) that reduces CO2 in CO2 absorbing liquid (rich solvent) that has absorbed the CO2 in the CO2 absorber (13) to regenerate the CO2 absorbing liquid, so that the regenerated absorbing liquid (lean solvent), having CO2 reduced in the regenerator (15), is reused in the CO2 absorber (13); a first to a fourth compressors (29-1, 29-2, 29-3, 29-4) that compress the CO2 gas released from the regenerator (15); and an O2 reducing apparatus arranged between the second compressor (29-2) and a second cooler (30-2) to reduce O2 in the CO2 gas.