Reboiled CO2 Separation Column for Low-Oxygen Carbon Dioxide

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current carbon dioxide purification processes from oxyfuel combustion and hydrogen PSA processes face challenges in achieving high recovery rates and low contaminant levels, particularly with oxygen and carbon monoxide, while also being energy-intensive and costly.

Innovation Solution

A method involving a mass transfer separation column system that separates impure liquid carbon dioxide to produce contaminant-enriched overhead vapor and carbon dioxide-enriched bottoms liquid, with reboiling and indirect heat exchange to enhance carbon dioxide recovery, and internal refrigeration using expanded carbon dioxide-enriched liquids to reduce energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional purification processes are used to remove oxygen and carbon monoxide from carbon dioxide, then contaminant levels are reduced, but energy consumption increases and recovery rates decrease

Engineering Contradiction:

Improvecarbon dioxide purityVSAvoidenergy consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent utilizes phase transitions of carbon dioxide, specifically the transition between liquid and vapor phases in a distillation column, to separate and purify carbon dioxide from contaminant gases. The process employs controlled heating and cooling to achieve phase changes that enable efficient separation while minimizing energy requirements compared to conventional methods.

Inventive Principle:

Principle #36Phase transitions

2Manufacturing precision

If conventional purification processes are used to remove oxygen and carbon monoxide from carbon dioxide, then contaminant levels are reduced, but carbon dioxide recovery rate decreases

Engineering Contradiction:

Improvecarbon dioxide purityVSAvoidcarbon dioxide recovery rate

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent implements a self-service mechanism where the purified carbon dioxide stream provides refrigeration duty to the distillation column through heat exchange, eliminating the need for external refrigeration systems. This internal recycling of energy maintains high carbon dioxide recovery rates while achieving the required purity levels, as the system uses its own output to sustain the purification process.

Inventive Principle:

Principle #25Self-service

3Productivity

If external refrigeration is used in carbon dioxide purification, then separation efficiency is improved, but device complexity and operational cost increase

Engineering Contradiction:

Improvepurification efficiencyVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent eliminates external refrigeration systems by implementing an internal heat exchange mechanism where the cold purified carbon dioxide stream directly provides refrigeration duty to the distillation column. This self-service approach reduces device complexity and operational costs while maintaining high purification efficiency, as the system uses its own process streams rather than requiring separate refrigeration equipment.

Inventive Principle:

Principle #25Self-service

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 achieves carbon dioxide recovery rates above 97% with low contaminant levels, specifically below 100 ppm oxygen and carbon monoxide, while minimizing energy consumption and operational costs.

Implementation Method 1

separating impure liquid carbon dioxide in a mass transfer separation column system to produce first contaminant-enriched overhead vapor and carbon dioxide-enriched bottoms liquid

Methodology Applied

Scientific EffectMass transfer: Diffusion

Implementation Method 2

separating impure liquid carbon dioxide in a mass transfer separation column system to produce first contaminant-enriched overhead vapor and carbon dioxide-enriched bottoms liquid

Methodology Applied

Scientific EffectPhase separation: Phase Change

Implementation Method 3

reboiling a portion of said carbon dioxide-enriched bottoms liquid by indirect heat exchange against crude carbon dioxide fluid to produce carbon dioxide-enriched vapor for said column system and cooled crude carbon dioxide fluid

Methodology Applied

Scientific EffectIndirect heat exchange: Heat Exchanger

Implementation Method 4

internal refrigeration using expanded carbon dioxide-enriched liquids to reduce energy consumption

Methodology Applied

Scientific EffectRefrigeration through expansion and vaporization: Joule-Thomson Effect

Implementation Method 5

internal refrigeration using expanded carbon dioxide-enriched liquids to reduce energy consumption

Methodology Applied

Scientific EffectEvaporative cooling: Evaporation

Data Source

PatentUS8257476B2Purification of carbon dioxide

Publication Date: 2012.09.04 AIR PROD & CHEM INC

AI summary

A first contaminant selected from oxygen and carbon monoxide is removed from impure liquid carbon dioxide using a mass transfer separation column system which is reboiled by indirect heat exchange against crude carbon dioxide fluid, the impure liquid carbon dioxide having a greater concentration of carbon dioxide than the crude carbon dioxide fluid. The invention has particular application in the recovery of carbon dioxide from flue gas generated in an oxyfuel combustion process or waste gas from a hydrogen PSA process. Advantages include reducing the level of the first contaminant to not more than 1000 ppm.