Method for producing a fluid enriched with carbon dioxide from a waste gas of a ferrous-metallurgy unit

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Solution Overview

Problem

Current methods for producing a fluid enriched in carbon dioxide from steelmaking unit waste gases face challenges such as variable pressure fluctuations, inefficiencies in carbon monoxide capture, high coke consumption, and energy consumption, particularly in maintaining consistent delivery pressure to adsorption units.

Innovation Solution

The method involves recycling gas to maintain consistent pressure in the adsorption unit, using a two-compressor system with adjustable outlet pressure and temperature-controlled separation units for efficient CO2 enrichment, allowing the adsorption unit to operate effectively across varying pressures and reducing energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the compressor operates at a substantially constant compression ratio, then the compression mechanism is simplified, but the pressure upstream of the adsorption unit varies when the waste gas pressure varies, reducing CO capture efficiency

Engineering Contradiction:
Improvecompression mechanism complexityVSAvoidCO capture efficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a variable compression ratio that adapts to changing waste gas pressure conditions. When waste gas pressure varies, the compressor dynamically adjusts its compression ratio to maintain substantially constant pressure upstream of the adsorption unit, ensuring consistent CO capture efficiency while handling variable inlet conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The compression ratio parameter is changed dynamically based on the waste gas pressure. By adjusting this key parameter, the system maintains optimal operating conditions for the adsorption unit despite variations in the waste gas source pressure, resolving the contradiction between simplified mechanics and reliable performance.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the adsorption unit operates at varying inlet pressures, then the system can handle variable waste gas pressure, but the CO removal efficiency decreases at lower pressures

Engineering Contradiction:
Improvepressure variation handlingVSAvoidCO removal efficiency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system dynamically adjusts the compression ratio to compensate for inlet pressure variations. When waste gas pressure drops, the compressor increases its compression ratio to maintain constant upstream pressure to the adsorption unit, ensuring high CO removal efficiency is maintained across all operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the waste gas pressure measurement to continuously adjust the compression ratio. This closed-loop control ensures that the adsorption unit receives gas at the optimal pressure for maximum CO removal efficiency, while the system adapts to handle variable inlet pressures from the waste gas source.

Inventive Principle:
Principle #23Feedback

3Reliability

If pressure control mechanisms are added to maintain constant delivery pressure, then CO capture efficiency is maintained, but the device complexity increases

Engineering Contradiction:
ImproveCO capture efficiencyVSAvoidpressure control system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Rather than adding complex pressure control mechanisms, the patent implements a variable compression ratio in the existing compressor. This dynamic adjustment of the compression ratio provides the necessary pressure control functionality while utilizing the existing compressor infrastructure, minimizing additional device complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The solution changes the operational parameter (compression ratio) of the existing compressor rather than adding new hardware components. This parameter-based control approach maintains CO capture efficiency through pressure stabilization while avoiding the complexity of additional pressure control mechanisms.

Inventive Principle:
Principle #35Parameter changes

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 near 100% CO efficiency and maintains high productivity by stabilizing pressure fluctuations, reducing coke consumption, and simplifying machinery operations, producing a fluid with at least 70% carbon dioxide concentration.

Implementation Method 1

a waste gas from a steelmaking unit is separated by adsorption in an adsorption unit (3)

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

by at least one cooling step followed by at least one phase separation step

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP2648825B1Method for producing a fluid enriched with carbon dioxide from a waste gas of a ferrous-metallurgy unit
Publication Date: 2017.08.02 LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE
  • EP2648825B1 patent drawingFigure 1
  • EP2648825B1 patent drawingFigure 2
  • EP2648825B1 patent drawingFigure 3

AI summary

The invention relates to a method for producing a fluid (7) enriched with carbon dioxide from a waste gas of a ferrous-metallurgy unit (HF), comprising: compressing at least one portion of the waste gas in a first compressor (C1); separating the optionally dried waste gas by means of an adsorption method in an adsorption unit (PSA) in order to produce a gas (6) enriched with carbon dioxide and depleted of carbon monoxide, and a gas (5) depleted of carbon dioxide and enriched with carbon monoxide; separating the gas (6) enriched with carbon dioxide in a separation unit (SP) in order to produce a fluid (7) enriched with carbon dioxide and a recirculation gas (9) containing carbon monoxide; recirculating the recirculation gas from the separation unit (SP) toward the adsorption unit (PSA) at the input pressure of the adsorption unit; and sending at least one portion of the gas (5) depleted of carbon dioxide to said ferrous-metallurgy unit (HF) or another ferrous-metallurgy unit.