Direct Air Capture Control to Limit Sorbent Water Uptake

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Solution Overview

Problem

Existing carbon dioxide capture systems face inefficiencies due to water absorption in desiccants and sorbents during non-standard operating conditions, such as system startup, shutdown, or malfunctions, which complicates and costs additional drying processes.

Innovation Solution

A method and system for carbon dioxide separation that includes sealing process chambers, adjusting pressure and temperature, and using recirculated dry air to minimize water absorption in desiccants and sorbents during special operations, followed by efficient preconditioning for normal operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the system operates in special modes (startup, shutdown, standstill), then operational flexibility is improved, but water absorption in desiccant and sorbent increases

Engineering Contradiction:
Improveoperational flexibilityVSAvoidwater absorption in desiccant and sorbent
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The control unit initiates a drying phase before normal operation begins, and maintains drying conditions during standstill periods. This preliminary action prevents water absorption from occurring in the first place during special operating modes, rather than dealing with the consequences afterward.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements periodic switching between drying phase and normal operation phase. During standstill periods, the system alternates between maintaining drying conditions and brief normal operation, preventing continuous water absorption while allowing operational flexibility.

Inventive Principle:
Principle #19Periodic action

2Quantity of substance

If additional drying processes are implemented during special operation, then water absorption is reduced, but system complexity and cost increase

Engineering Contradiction:
Improvewater absorption in desiccant and sorbentVSAvoiddrying process complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The existing process chambers and desiccant materials serve dual functions: they perform normal CO2 separation during standard operation and simultaneously function as drying apparatus during special modes. No separate dedicated drying equipment is required, as the same components fulfill multiple purposes.

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

Solution Approach 2:

The system uses its own internal resources to maintain dry conditions during special operation. The control unit manages the drying phase by controlling the existing airflow system and desiccant, without requiring external drying equipment or additional subsystems.

Inventive Principle:
Principle #25Self-service

3Loss of time

If the system maintains dry conditions during special operation, then startup time is reduced, but energy consumption increases

Engineering Contradiction:
Improvestartup timeVSAvoidenergy consumption during special operation
Core Design Contradiction:
Loss of timeVSUse of energy by moving object

Solution Approach 1:

The control unit dynamically adjusts the duration and intensity of the drying phase based on the specific special mode (startup, shutdown, or standstill) and environmental conditions. The drying period is extended or reduced as needed, optimizing the balance between maintaining dry conditions and minimizing energy consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters such as airflow rate, temperature, and drying phase duration to optimize energy efficiency. During mild conditions, lower energy settings are used, while during humid conditions, higher energy consumption is applied temporarily to ensure dry conditions are maintained.

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

Enhances system efficiency by minimizing water absorption in desiccants and sorbents during non-standard conditions, shortening startup times, and maintaining optimal drying and adsorption conditions for swift return to normal operation.

Implementation Method 1

wherein the airflow is dried in the first process chamber

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

Adsorbing carbon dioxide from the dried airflow with a sorbent material in the second process chamber

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

Desorbing the carbon dioxide adsorbed in the sorbent material

Methodology Applied
Scientific EffectDesorption: Desorption

Data Source

PatentEP4647145A1Method for controlling a system for separating carbon dioxide from ambient air, and system
Publication Date: 2025.11.12 VOLKSWAGEN AG
  • EP4647145A1 patent drawingFigure 1
  • EP4647145A1 patent drawingFigure 2
  • EP4647145A1 patent drawing

AI summary

The invention relates to a method for controlling a system (10) for separating carbon dioxide (48) from the ambient air (74). The method distinguishes between normal operation, in which carbon dioxide (48) is separated from the ambient air (78), and special operation, which is not primarily used for separating carbon dioxide (48). Normal operation comprises conveying (110) an air stream (68) of the ambient air (74) into a first process chamber (26) of the system, wherein the air stream (68) is dried in the first process chamber (26). The dried air stream (68) of the ambient air is passed from the first process chamber (26) into a second process chamber (27), in which adsorption and subsequent desorption of carbon dioxide (48) takes place. The desorbed carbon dioxide is stored in a storage unit (16).It is provided that the system (10) is operated in a special mode that deviates from normal operation, either before or after normal operation, wherein the system (10) is operated in the special mode with operating parameters that differ from those of normal operation. The invention further relates to a system (10) for carrying out such a method.