CO2 Recovery Tower Cleaning Control for Low-Load Heat Reduction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The concentration of the absorption agent in condensed water used for cleaning in CO2 recovery systems is often high, leading to inefficiencies and increased heat requirements, particularly during low-load conditions, affecting the operation efficiency of the CO2 recovery apparatus.

Innovation Solution

A CO2 recovery apparatus and method that includes control devices to adjust the supply of condensed water as a cleaning liquid, maintaining the absorption agent concentration below a predetermined value, thereby minimizing the supply amount and reducing heat requirements in the regeneration tower.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If CO2 is separated and recovered from flue gas using conventional methods, then CO2 recovery efficiency is improved, but the device complexity and cost increase due to requiring large-scale equipment and multiple processing units

Engineering Contradiction:
ImproveCO2 recovery efficiencyVSAvoidequipment structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The flue gas treatment process is segmented into distinct functional modules: a first treatment unit handling high CO2 concentration gas streams, and a second treatment unit handling low CO2 concentration gas streams. This segmentation allows each unit to be optimized for its specific concentration range, improving overall recovery efficiency while keeping individual unit complexities manageable

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system employs a multi-functional integrated device that combines cooling, condensation, and CO2 separation capabilities within a single apparatus. The device can handle both high and low CO2 concentration streams through different operational modes or integrated processing stages, reducing the need for multiple separate large-scale equipment while maintaining high recovery efficiency

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

2Measurement precision

If flue gas is cooled to condense water vapor for CO2 separation, then separation efficiency is improved, but energy consumption increases due to the cooling requirement

Engineering Contradiction:
ImproveCO2 separation efficiencyVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system converts the harmful effect of water vapor interference in CO2 separation into a beneficial process step. By cooling the flue gas to condense and remove water vapor, the system eliminates the interference that water vapor causes in CO2 separation, thereby improving separation efficiency. The condensed water can also be recovered as a useful byproduct

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

Solution Approach 2:

The cooling and condensation process acts as an intermediary step that prepares the flue gas for efficient CO2 separation. By removing water vapor through condensation before the separation process, the system creates optimal conditions for CO2 recovery, improving the effectiveness of subsequent separation operations

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If high concentration CO2 gas is mixed with low concentration CO2 gas, then the overall CO2 concentration becomes moderate, but the productivity of CO2 recovery decreases

Engineering Contradiction:
ImproveCO2 concentration uniformityVSAvoidCO2 recovery throughput
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The system segments the CO2 recovery process into separate handling paths for high concentration and low concentration gas streams. Each path is processed independently through optimized treatment units, avoiding the need to mix streams. This segmentation maintains high recovery throughput while ensuring stable and uniform CO2 concentration in the recovered product

Inventive Principle:
Principle #1Segmentation

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 configuration improves the operation efficiency of the CO2 recovery apparatus by reducing the supply of condensed water and heat needed, while maintaining absorption agent concentration within acceptable limits, thus enhancing overall system performance.

Implementation Method 1

a cooling unit configured to cool the flue gas

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

a separation unit configured to separate co2 from the flue gas

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3842121B1Co2 recovery apparatus and co2 recovery method
Publication Date: 2026.04.29 MITSUBISHI HEAVY IND LTD
  • EP3842121B1 patent drawingFigure 1
  • EP3842121B1 patent drawingFigure 2
  • EP3842121B1 patent drawingFigure 3

AI summary

This CO2 recovery device is provided with: an absorption tower that is configured so as to absorb CO2 of an exhaust gas in a CO2 absorption liquid containing an absorbent; a recycling tower for recycling the CO2 absorption liquid from the absorption tower; a recirculated water drum for separating the CO2-containing gas discharged from the recycling tower into CO2 gas and condensed water; a first cleaning part that is provided in a gas-phase portion of the recycling tower and configured so as to remove the absorbent included in the CO2-containing gas distributed through the gas-phase portion, by using a first cleaning solution including at least the condensed water from the recirculated water drum or water derived from the condensed water; and a control unit that is configured so as to adjust the amount of the first cleaning solution supplied to the first cleaning part so that a concentration of the absorbent in the condensed water is maintained at a prescribed value or lower.