Two-Stage Adsorbent for CO2 Capture

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Solution Overview

Problem

Conventional swing adsorption processes for CO2 capture from flue gas are inefficient due to high steam usage and energy requirements, particularly in low-pressure, low-concentration CO2 environments, which increases the cost of electricity generation and makes CO2 capture economically unfeasible.

Innovation Solution

A two-stage adsorption process utilizing a steam-sensitive metal organic framework (MOF) as the first stage adsorbent and a steam-insensitive adsorbent with a metal compound as the second stage, employing temperature swing adsorption (TSA) and displacement desorption (DD) processes to reduce steam usage and enhance CO2 concentration, with the second stage adsorbent being disposed within the void space of the first stage adsorbent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional swing adsorption processes are used for CO2 capture from flue gas, then CO2 separation is achieved, but steam usage and energy requirements become excessively high

Engineering Contradiction:

ImproveCO2 capture efficiencyVSAvoidsteam usage

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The adsorption process is divided into two distinct stages using different adsorbent materials: a first stage adsorbent for initial CO2 capture and a second stage adsorbent for enhanced capture. This segmentation allows each stage to be optimized for specific conditions, reducing overall steam usage while maintaining high CO2 capture efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite adsorbent systems where a second stage adsorbent is disposed within the void space of the first stage adsorbent. This composite structure enables synergistic interaction between different adsorbent materials, improving CO2 capture efficiency while minimizing the energy and steam required for regeneration.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If conventional swing adsorption processes are used for CO2 capture, then CO2 separation is achieved, but the cost of electricity generation increases significantly

Engineering Contradiction:

ImproveCO2 capture efficiencyVSAvoidcost of electricity generation

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

By segmenting the adsorption process into two stages with different adsorbents, the system optimizes CO2 capture at each stage, reducing the total energy input required. This lowers the operational costs associated with electricity generation while maintaining effective CO2 separation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes temperature swing adsorption (TSA) and displacement desorption (DD) processes that operate under optimized temperature and pressure parameters. These parameter changes enable efficient CO2 capture with reduced energy consumption, thereby decreasing the cost of electricity generation.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If single stage adsorption is used, then process simplicity is maintained, but CO2 concentration and recovery efficiency are insufficient

Engineering Contradiction:

Improveprocess simplicityVSAvoidCO2 concentration

Core Design Contradiction:

Device complexityVSQuantity of substance

Solution Approach 1:

The adsorption system is segmented into two stages with distinct adsorbents positioned in sequence. The first stage adsorbent captures initial CO2, and the second stage adsorbent further concentrates CO2 by capturing additional CO2 from the effluent of the first stage. This segmentation significantly enhances CO2 concentration and recovery efficiency while maintaining reasonable process complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second stage adsorbent is disposed within the void space of the first stage adsorbent, creating a nested configuration. This nesting allows the second stage to utilize the space efficiently and further concentrate CO2 as the gas stream passes through both stages, achieving high CO2 concentration without excessive complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 reduces steam usage, achieving a higher CO2 concentration and recovery efficiency while minimizing energy consumption, thereby making CO2 capture more economical and environmentally friendly.

Implementation Method 1

employing temperature swing adsorption (TSA) and displacement desorption (DD) processes

Methodology Applied

Scientific EffectTemperature swing adsorption: Adsorption

Implementation Method 2

employing temperature swing adsorption (TSA) and displacement desorption (DD) processes

Methodology Applied

Scientific EffectDisplacement desorption: Desorption

Data Source

PatentUS10029205B2Two stage adsorbent and process cycle for fluid separations

Publication Date: 2018.07.24 EXXONMOBIL TECHNOLOGY & ENGINEERING CO

AI summary

In various aspects, apparatuses, systems, and methods are provided for performing two stage separation of CO2 from a gaseous stream. The first stage adsorbent can be comprised of a plurality of cylindrical or substantially cylindrical rings. The first stage adsorbent can be comprised of a metal organic framework. The second stage adsorbent can be subject to a displacement desorption process. The second stage adsorbent can be comprised of a support and a metal compound selected from the group consisting of alkali or alkaline earth. The first and second stage adsorbent can be arranged concentrically for space and efficiency considerations.