CO2 Separation Device Pressure Reduction Phase Separation Heat Recovery

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Solution Overview

Problem

Current carbon dioxide separation devices face inefficiencies in sensible heat recovery and increased re-liquefaction ratios due to temperature differences between CO2-rich and lean solutions, which affect heat exchange and energy requirements in the stripping tower.

Innovation Solution

A carbon dioxide separation device incorporating a pressure reduction and phase separation unit that depressurizes the CO2-rich solution, allowing for heat exchange with a lean solution to separate phases into gas and liquid, and reintroduces a portion of the CO2-rich solution into the stripping tower before the heat exchanger to optimize heat recovery and reduce re-liquefaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the CO2-rich solution is heated in the heat exchanger to recover sensible heat, then the sensible heat recovery efficiency is improved, but the re-liquefaction ratio increases

Engineering Contradiction:
Improvesensible heat recovery efficiencyVSAvoidre-liquefaction ratio
Core Design Contradiction:
Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The CO2-rich solution flow is divided into two separate streams: one stream (first CO2-rich solution) is heated in the heat exchanger to recover sensible heat, while another stream (second CO2-rich solution) bypasses the heat exchanger and is directly introduced into the stripping tower. This segmentation allows the system to optimize heat recovery while controlling the re-liquefaction ratio by adjusting the flow distribution between the two streams.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the flow rate parameter of the CO2-rich solution by introducing a bypass stream. By adjusting the proportion of CO2-rich solution that bypasses the heat exchanger versus the proportion that is heated, the system can control the re-liquefaction ratio while maintaining effective sensible heat recovery, thus resolving the contradiction between these two parameters.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If more CO2-rich solution is heated in the heat exchanger, then the heat recovery amount increases, but the cooling duty and energy requirements increase

Engineering Contradiction:
Improveheat recovery amountVSAvoidcooling duty
Core Design Contradiction:
Loss of energyVSUse of energy by stationary object

Solution Approach 1:

The CO2-rich solution is segmented into two streams with different thermal paths. The first stream undergoes heat exchange to recover sensible heat, while the second stream bypasses the heat exchanger and provides cooler fluid to the stripping tower. This reduces the overall cooling duty required while maintaining effective heat recovery from the first stream.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bypass stream of CO2-rich solution acts as an intermediary that mixes with the heated stream or directly contacts the stripping tower, providing a cooling effect that reduces the cooling duty of the condenser while allowing the heat exchanger to effectively recover sensible heat from the first stream.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances sensible heat recovery efficiency by increasing the heat capacity of the CO2-rich solution and reduces the re-liquefaction ratio and cooling duty, thereby minimizing energy requirements for reheating and condensation.

Implementation Method 1

separate a phase of the CO2-rich-solution into gas and liquid by means of heat from a lean solution flowing from a stripping tower to an exchanger

Methodology Applied
Scientific EffectPhase separation: Phase Change

Implementation Method 2

heat exchange between a lean solution and the CO2-rich-solution when the CO2-rich-solution is depressurized

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

sensible heat recovery efficiency is improved by exchanging heat between a CO2-rich-solution and a lean solution

Methodology Applied
Scientific EffectSensible heat recovery: Conduction (thermal)

Implementation Method 4

when the CO2-rich-solution is depressurized by a heat exchanger

Methodology Applied
Scientific EffectPressure reduction: Depressurisation

Data Source

PatentEP3006099B1Carbon dioxide separation device having improved sensible heat recovery efficiency using pressure reduction and phase separation
Publication Date: 2018.08.15 KEPCO ENG & CONSTR CO INC
  • EP3006099B1 patent drawingFigure 1
  • EP3006099B1 patent drawingFigure 2
  • EP3006099B1 patent drawingFigure 3

AI summary

The present invention provides a carbon dioxide separation device comprising: an absorption tower for causing reaction between carbon dioxide and an absorbent; a first piping through which co2-rich-solution moves; a pressure reduction and phase separation unit arranged on the first piping, for separating the phase of the co2-rich-solution into gas and liquid; a stripping tower, into which the co2-rich-solution in gas and liquid states flows, and which separates carbon dioxide from the co2-rich-solution; a second piping for connecting the stripping tower and the pressure reduction and phase separation unit such that a lean solution, which results from removal of the carbon dioxide, moves; and a reheater for providing the stripping tower with heat such that carbon dioxide is separated from the co2-rich-solution, wherein the lean solution flows into the pressure reduction and phase separation unit, and the co2-rich-solution undergoes phase separation into gas and liquid, by means of heat of the lean solution, and then flows into the stripping tower.