Apparatus and method for separating co2 at low temperature comprising a step of separation by permeation

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Solution Overview

Problem

Existing low-temperature CO2 purification methods face challenges in precise temperature regulation of membranes, which can lead to mechanical stress and reduced efficiency, especially during start-up and transient operating phases.

Innovation Solution

A method involving a heat exchanger that splits the gas stream to be sent to the membranes into two parts, with one part being heated to the hot end of the exchanger and the other part remaining unheated, allowing for controlled temperature regulation at the membrane inlet, and a gradual cooling process to prevent mechanical stress, enabling optimal membrane performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If membranes are operated at low temperature to optimize CO2 yield and selectivity, then membrane performance is improved, but mechanical stress increases and reliability decreases during start-up and transient phases

Engineering Contradiction:
ImproveCO2 yieldVSAvoidmembrane integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by implementing a gradual cooling protocol before membrane operation. The system performs a controlled temperature reduction from ambient temperature to the operating temperature of -10°C to -40°C over a defined period, preventing thermal shock and mechanical stress on the membrane during start-up. This preliminary temperature adjustment ensures membrane integrity while maintaining optimal CO2 yield and selectivity during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by making the temperature profile adaptive and controllable. The system uses a programmable temperature control mechanism that can adjust the cooling rate and operating temperature based on membrane type and operational conditions. This dynamic control allows optimization of CO2 yield and selectivity while preventing mechanical stress through real-time temperature management during transient and steady-state operations.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If gas is directly cooled to membrane operating temperature, then energy consumption is reduced, but mechanical stress on membranes increases due to thermal shock

Engineering Contradiction:
Improveenergy consumptionVSAvoidmembrane mechanical integrity
Core Design Contradiction:
Loss of energyVSStrength

Solution Approach 1:

The patent applies preliminary action by implementing a gradual cooling protocol before membrane operation. The system performs a controlled temperature reduction from ambient temperature to the operating temperature of -10°C to -40°C over a defined period, preventing thermal shock and mechanical stress on the membrane during start-up. This preliminary temperature adjustment ensures membrane integrity while maintaining optimal CO2 yield and selectivity during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by making the temperature profile adaptive and controllable. The system uses a programmable temperature control mechanism that can adjust the cooling rate and operating temperature based on membrane type and operational conditions. This dynamic control allows optimization of CO2 yield and selectivity while preventing mechanical stress through real-time temperature management during transient and steady-state operations.

Inventive Principle:
Principle #15Dynamics

3Productivity

If temperature control during membrane operation is not precise, then device complexity is reduced, but CO2 purification efficiency decreases

Engineering Contradiction:
ImproveCO2 purification efficiencyVSAvoidtemperature control system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies feedback by implementing a temperature control system with sensors and regulatory mechanisms. The system continuously monitors the temperature at the membrane inlet and adjusts the cooling rate to maintain the optimal operating range of -10°C to -40°C. This feedback control ensures precise temperature management during both transient and steady-state operations, maximizing CO2 yield and selectivity while preventing mechanical stress on the membrane.

Inventive Principle:
Principle #23Feedback

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 ensures precise temperature control and gradual cooling of membranes, enhancing their mechanical integrity and operational efficiency, particularly during start-up and normal operation, thereby improving CO2 purification yields and reducing energy consumption.

Implementation Method 1

A method involving a heat exchanger that splits the gas stream to be sent to the membranes into two parts, with one part being heated to the hot end of the exchanger and the other part remaining unheated, allowing for controlled temperature regulation at the membrane inlet

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a gas from the first system is treated in a membrane system to produce a permeate and a non-permeate

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentEP3471858B1Apparatus and method for separating co2 at low temperature comprising a step of separation by permeation
Publication Date: 2020.03.18 LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE
  • EP3471858B1 patent drawingFigure 1
  • EP3471858B1 patent drawingFigure 2
  • EP3471858B1 patent drawingFigure 3

AI summary

The invention relates to a method for separating a mixture (1) containing carbon dioxide, wherein the mixture is cooled in a heat exchanger (H) and partially condensed, and a first liquid (17) is separated from the mixture in a first system operating at low temperature comprising at least one first phase separator (PS1), and a gas (23) from the first system is treated in a membrane system (M) so as to produce a permeate (55) and a non-permeate (53), the gas from the first system being divided into two portions, a first portion (26) being sent to the membrane system without having been reheated and a second portion (24) being reheated to at least one intermediate temperature of the heat exchanger and then sent to the membrane system without having been cooled.