Membrane Absorption CO2 Capture with Low Viscosity Solvent

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Solution Overview

Problem

Current CO2 capture technologies from power plant flue gases, such as amine absorption and membrane processes, face challenges in cost-effectiveness and long-term stability due to high levelized cost of energy and liquid side concentration polarization, which affects the efficiency and durability of the separation process.

Innovation Solution

A membrane absorption process using a CO2 selective solvent with viscosity between 0.2 and 7 cP, where the CO2-containing gas stream contacts one side of a membrane element and the solvent flows on the other side, allowing CO2 to permeate and be chemically absorbed, with a system including a desorber for solvent regeneration and return to the absorber to maintain efficiency and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional amine absorption is used for CO2 capture, then CO2 separation can be achieved, but the levelized cost of energy increases by 75-85%

Engineering Contradiction:

ImproveCO2 capture rateVSAvoidlevelized cost of energy

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent changes the physical parameter of solvent viscosity by selecting solvents with viscosity between 0.2 and 7 cP, which improves mass transfer characteristics and reduces the energy penalty associated with conventional amine absorption processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a membrane contactor as an intermediary device between the gas phase and liquid solvent, facilitating CO2 transfer while reducing the overall energy requirement compared to direct contact absorption methods

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If membrane contactor systems are used for CO2 capture, then separation can be achieved, but liquid side concentration polarization affects long-term stability

Engineering Contradiction:

ImproveCO2 separation efficiencyVSAvoidlong-term stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent addresses concentration polarization by carefully selecting solvents with optimized viscosity parameters (0.2-7 cP) that maintain adequate mass transfer coefficients while preventing excessive concentration buildup at the membrane interface, thereby improving long-term operational stability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional high-viscosity amine solvents with low-viscosity CO2-selective solvents, fundamentally changing the fluid mechanics at the membrane interface to reduce concentration polarization effects and improve reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If high viscosity solvent is used for CO2 absorption, then chemical absorption capacity increases, but mass transfer rate decreases due to concentration polarization

Engineering Contradiction:

ImproveCO2 absorption capacityVSAvoidCO2 capture rate

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent optimizes the viscosity parameter of the absorption solvent to a specific range (0.2-7 cP) that balances CO2 absorption capacity with mass transfer rate, preventing concentration polarization while maintaining adequate chemical absorption capacity

Inventive Principle:

Principle #35Parameter changes

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 reduces concentration polarization, enhances CO2 capture rates, and improves the long-term stability and cost-effectiveness of the separation process by maintaining a stable CO2 removal rate and reducing fouling, while maintaining high selectivity and membrane lifetime.

Implementation Method 1

The CO2 permeates through the hollow fiber membrane pores and is chemically absorbed into the solvent

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

The CO2 permeates through the hollow fiber membrane pores and is chemically absorbed into the solvent

Methodology Applied

Scientific EffectChemical absorption: Absorption (physical)

Implementation Method 3

This approach reduces concentration polarization, enhances CO2 capture rates

Methodology Applied

Scientific EffectConcentration polarization reduction: Diffusion

Data Source

PatentUS11471825B2Membrane absorption process for CO<sub>2 </sub>capture

Publication Date: 2022.10.18 GAS TECH INST

AI summary

Processes and systems for the capture of CO2 from a CO2-containing gas stream are provided. The CO2-containing gas stream is passed to a membrane contactor absorber wherein the CO2-containing gas contacts or passes a first side of a membrane element while a CO2 selective solvent with a viscosity between 0.2 and 7 cP contacts, passes or flows on second side of the membrane, opposed to the first side. The CO2 permeates through the hollow fiber membrane pores and is chemically absorbed into the solvent.