Flue Gas Split Recycling for Lower-Cost Carbon Oxide Utilization

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Solution Overview

Problem

Existing processes for capturing carbon dioxide from flue gases in MTO units are costly and energy-intensive, with high capital and operational expenses due to the presence of impurities and the need for extensive pretreatment, and there is a need for a more efficient method to reduce greenhouse gas emissions while improving energy efficiency.

Innovation Solution

A process that separates flue gas into two streams, combusting one stream to produce a carbon dioxide-rich gas for recycling and using it as synthetic air in the MTO unit, while recycling the other stream to an oxygenate production unit, reducing nitrogen content and minimizing compression energy costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional flue gas treatment methods are used to remove carbon dioxide, then greenhouse gas emissions are reduced, but capital and operational costs increase significantly

Engineering Contradiction:

Improvegreenhouse gas emissionsVSAvoidcapital and operational costs

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent converts the harmful carbon dioxide emissions into a valuable resource by recycling it as a feedstock for oxygenate production. The flue gas containing CO2 is routed to a reactor where it is converted into oxygenates like methanol, transforming the waste emission into a useful chemical product and eliminating the need for expensive separation and disposal systems

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical parameters of the flue gas by introducing it to a catalytic reaction environment. The CO2 in the flue gas undergoes chemical transformation into oxygenates through controlled reaction conditions, changing the composition and utility of the gas stream from a harmful emission to a valuable chemical feedstock

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If extensive pretreatment is applied to flue gas for carbon dioxide removal, then emission control is achieved, but operational expenses and energy consumption increase

Engineering Contradiction:

Improvecarbon dioxide emissionsVSAvoidenergy consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

Instead of spending energy to separate and remove CO2, the patent uses energy to convert CO2 into valuable oxygenates through catalytic reactions. The flue gas is directed to a reactor where CO2 is transformed into chemical products, converting what would be an energy-intensive separation problem into an energy-productive synthesis process

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If flue gas is discharged directly into the atmosphere, then operational complexity is reduced, but greenhouse gas emissions increase

Engineering Contradiction:

Improveflue gas treatment systemVSAvoidgreenhouse gas emissions

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent makes the flue gas processing system multi-functional: it simultaneously handles emission control and produces valuable chemical products. The same flue gas stream that would normally require complex treatment for emission control is instead routed to produce oxygenates, achieving both environmental compliance and economic benefit through a single integrated process

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Object-affected harmful factors

If carbon dioxide is captured and separated from flue gas, then emissions are controlled, but capital expenditure increases due to larger equipment requirements

Engineering Contradiction:

Improvecarbon dioxide emissionsVSAvoidequipment size

Core Design Contradiction:

Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The patent eliminates the need for large-scale CO2 separation equipment by converting CO2 into valuable products in situ. The flue gas is fed directly into a reactor where CO2 is transformed into oxygenates, avoiding the need for expensive and space-consuming membrane separators, absorption towers, or cryogenic separation units that would be required for pure CO2 capture

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 capital and operational costs by recycling carbon dioxide and carbon monoxide, enhancing energy efficiency, and allows for the utilization of carbon oxides as valuable feedstocks for methanol and olefin production.

Implementation Method 1

combusting one stream to produce a carbon dioxide-rich gas

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

recycling carbon dioxide and carbon monoxide, enhancing energy efficiency

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS20250346541A1Process for utilizing carbon oxides in a flue gas stream

Publication Date: 2025.11.13 UOP LLC

AI summary

A process of separating carbon oxides from a flue gas stream is disclosed. The process comprises separating a flue gas stream into a first flue gas stream and a second flue gas stream. The first flue gas stream is combusted with an oxygen stream in a boiler to provide a carbon dioxide rich flue gas stream. A carbon dioxide recycle stream is taken from the carbon dioxide rich flue gas stream. The second flue gas stream is recycled to an oxygenate production unit. The carbon dioxide recycle stream is recycled to the boiler or to a regenerator or both.