Cooling Tower CO2 Capture via Solvent Concentration Optimization

Solution Overview

Problem

Conventional cooling towers do not capture carbon dioxide from the atmosphere, contributing to global warming, and existing direct air capture systems are costly and inefficient, with high capital and operating expenses due to separate equipment and energy consumption.

Innovation Solution

Integration of a liquid CO2-absorbent solvent, such as monoethanolamine, into cooling water in cooling towers allows concurrent CO2 capture and water evaporation, with a solvent retention system and regeneration process to recover and reuse the solvent, reducing costs and environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a liquid CO2-absorbent solvent is added to cooling water to enable CO2 capture, then CO2 absorption capability is improved, but solvent loss due to evaporation worsens because cooling towers reject heat via evaporation

Engineering Contradiction:

ImproveCO2 absorption capabilityVSAvoidsolvent loss

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent changes the concentration parameter of the solvent in the cooling water to an optimized range (0.1-10% by weight) where CO2 absorption is effective but solvent evaporation is minimized. This parameter optimization resolves the contradiction by finding the sweet spot between absorption capability and loss prevention

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a solvent retention system as an intermediary component that captures evaporated solvent and returns it to the cooling water loop. This mediator prevents solvent loss while maintaining the CO2 absorption function

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If conventional cooling towers are used without CO2 capture functionality, then operational simplicity is maintained, but environmental harm increases due to no CO2 reduction

Engineering Contradiction:

Improvesystem simplicityVSAvoidCO2 emissions

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent makes the cooling tower multi-functional by enabling it to perform both its original cooling function and a new CO2 capture function simultaneously. The cooling water serves dual purposes: cooling the system and absorbing CO2 from the atmosphere, thus eliminating the need for separate DAC equipment

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the cooling tower system with direct air capture functionality into a single hybrid system. The CO2 absorption, cooling, and solvent retention functions are combined in one integrated system, maintaining operational simplicity while adding environmental benefit

Inventive Principle:

Principle #5Merging (Combining)

3Quantity of substance

If separate DAC equipment is used for CO2 capture, then CO2 absorption is achieved, but capital and operating expenses increase significantly

Engineering Contradiction:

ImproveCO2 capture amountVSAvoidsystem cost

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent makes the cooling tower multi-functional by enabling it to perform both its original cooling function and a new CO2 capture function simultaneously. The cooling water serves dual purposes: cooling the system and absorbing CO2 from the atmosphere, thus eliminating the need for separate DAC equipment

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the cooling tower system with direct air capture functionality into a single hybrid system. The CO2 absorption, cooling, and solvent retention functions are combined in one integrated system, maintaining operational simplicity while adding environmental benefit

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

This hybrid system achieves cost-effective CO2 capture at $100 per ton, meeting the U.S. Department of Energy's target, while reducing capital and operating expenses and minimizing solvent loss, making it more competitive than commercialized DAC systems.

Implementation Method 1

a liquid absorbent solvent (e.g., monoethanolamide (MEA)) is added to cooling water to form a coolant in a process to absorb CO2 from ambient air

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

cooling towers reject heat via evaporation

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS20240325965A1Direct air capture of carbon dioxide

Publication Date: 2024.10.03 RGT UNIV OF CALIFORNIA

AI summary

A system for direct air capture (DAC) of carbon dioxide uses a liquid CO2-absorbent solvent that enables the hybridization of a cooling tower with CO2 DAC systems. A liquid solvent such as monoethanolamine (MEA) is added to cooling water to absorb CO2 from ambient air, the cooling water is used for its original purpose, and CO2 is recovered from the cooling water in a novel process. Initially, this combination of CO2 absorbent and cooling water would appear to be undesirable, since liquid CO2 solvents such as MEA are hygroscopic, and cooling towers reject heat via evaporation. However, an absorbent concentration range was identified where CO2 could be still absorbed and water evaporated, and a novel process for absorbent solvent regeneration was created.