CO2 Recovery Unit Temperature Control for Absorption Efficiency

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Solution Overview

Problem

Current CO2 recovery units face challenges in achieving high CO2 absorption rates and energy efficiency, particularly when dealing with gases having low CO2 partial pressures, such as combustion flue gases from boilers, and those with high CO2 partial pressures, like synthetic gases from direct reducing furnaces.

Innovation Solution

A CO2 recovery unit comprising multiple CO2 absorption units and a regenerator, where the temperature of the CO2 absorbent is controlled based on measured temperatures to optimize CO2 absorption rates, with specific temperature ranges (50° C to 60° C) and CO2 partial pressures (50 kPa or more), and filling material charging height ratios (1:3 to 3:1) to enhance absorption efficiency and reduce steam consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the temperature of CO2 absorbent is increased to improve CO2 absorption rate, then the CO2 absorption rate increases, but the steam consumption amount increases

Engineering Contradiction:

ImproveCO2 absorption rateVSAvoidsteam consumption amount

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The CO2 absorption process is divided into multiple absorption units (first CO2 absorption unit, second CO2 absorption unit, etc.) arranged in series. Each unit operates at optimized temperature conditions, allowing the system to achieve high overall absorption rate without requiring all absorbent to be heated to high temperatures, thus reducing steam consumption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The CO2 absorbent is pre-heated to a controlled temperature range (50-60°C) before entering the second CO2 absorption unit. This preliminary temperature control ensures optimal absorption conditions are met while avoiding excessive energy input that would increase steam consumption in the regenerator.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 3:

A temperature measurement device measures the temperature of CO2 absorbent supplied from the CO2 absorber to the regenerator, and a control device adjusts the temperature of CO2 absorbent supplied to the second absorption unit based on this measurement. This feedback control maintains absorption efficiency while minimizing energy waste and steam consumption.

Inventive Principle:

Principle #23Feedback

2Productivity

If multiple CO2 absorption units are added to improve CO2 absorption rate, then the CO2 absorption rate increases, but the device complexity increases

Engineering Contradiction:

ImproveCO2 absorption rateVSAvoidnumber of absorption units

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Multiple CO2 absorption units are combined into a single integrated CO2 absorber device with shared infrastructure (support structures, piping, measurement and control systems). This merging approach achieves high CO2 absorption rates through multiple stages while minimizing the increase in overall device complexity compared to separate independent units.

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

The solution achieves an excellent CO2 absorption rate and significant energy savings by optimizing the CO2 absorption process across varying CO2 partial pressures, reducing the circulation amount of the CO2 absorbent and steam consumption in the regenerator.

Implementation Method 1

causing a CO2 containing gas to be treated to contact a CO2 absorbent so that CO2 contained in the gas to be treated is absorbed to the CO2 absorbent

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

regenerates a CO2 absorbent by heating the second CO2 absorbent so that CO2 is discharged from the second CO2 absorbent

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

heating the second CO2 absorbent so that CO2 is discharged from the second CO2 absorbent

Methodology Applied

Scientific EffectDesorption: Desorption

Data Source

PatentUS10449481B2CO<sub>2 </sub>recovery unit and CO<sub>2 </sub>recovery method

Publication Date: 2019.10.22 MITSUBISHI HEAVY IND LTD

AI summary

A CO2 recovery unit and a CO2 recovery method capable of having an excellent CO2 absorption rate and saving energy are provided. A CO2 recovery unit of the invention includes: a CO2 absorber which includes an upper CO2 absorption unit obtaining a CO2 absorbent by causing a flue gas containing CO2 to contact a CO2 absorbent and a lower CO2 absorption unit obtaining a CO2 absorbent by causing the CO2 absorbent to contact a flue gas containing CO2; a CO2 absorbent regenerator which obtains the CO2 absorbent by heating the CO2 absorbent a thermometer which measures a temperature of the CO2 absorbent supplied from the CO2 absorber to the CO2 absorbent regenerator; and a control device which controls a temperature of the CO2 absorbent supplied to the lower CO2 absorption unit based on the temperature of the CO2 absorbent measured by the thermometer.