Denitrogenation Column Reboiling with Expanded High-Pressure CO

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Solution Overview

Problem

Current methane scrubbing processes for separating carbon monoxide and nitrogen face challenges due to close bubble points, leading to energy losses and inefficiencies in reboiling, particularly in denitrogenation columns, where medium pressure carbon monoxide is compressed and reused, causing instability and energy inefficiencies.

Innovation Solution

A method that measures the flow of gas rich in carbon monoxide to trigger the expansion of high-pressure carbon monoxide in the denitrogenation column, allowing for independent sizing of the reboiling fraction and eliminating the need for medium pressure carbon monoxide vaporization, which is supplemented by 'backup' high-pressure carbon monoxide, ensuring consistent reboiling without destabilizing the exchange line.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If medium pressure carbon monoxide is vaporized in the exchange line to cover reboiling needs, then the contribution of the carbon monoxide compressor to medium pressure is reduced, but the vaporized flow rate is limited by the exchange line capacity and reboiling fraction constraints, leading to energy loss

Engineering Contradiction:
Improveenergy lossVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The invention extracts the reboiling function from the exchange line by introducing a dedicated reboiling column. This separates the vaporization function (performed by the exchange line) from the reboiling function (performed by the reboiling column), allowing each to be optimized independently. The exchange line can vaporize medium pressure carbon monoxide without being constrained by reboiling fraction limits, while the reboiling column provides the necessary reboiling capacity through its own heating system.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the reboiling process into two independent parts: (1) vaporization of medium pressure carbon monoxide in the exchange line, and (2) reboiling in the dedicated reboiling column. This segmentation removes the coupling constraint where the exchange line had to simultaneously perform both vaporization and reboiling functions, allowing the system to operate at optimal efficiency for each function.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If the reboiling fraction from vaporized medium pressure carbon monoxide is increased, then more reboiling needs are covered, but the exchange line becomes destabilized and the flow rate of vaporized medium pressure carbon monoxide must be reduced

Engineering Contradiction:
Improvereboiling flow rateVSAvoidexchange line stability
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The invention extracts the reboiling function from the exchange line by introducing a dedicated reboiling column. This separates the vaporization function (performed by the exchange line) from the reboiling function (performed by the reboiling column), allowing each to be optimized independently. The exchange line can vaporize medium pressure carbon monoxide without being constrained by reboiling fraction limits, while the reboiling column provides the necessary reboiling capacity through its own heating system.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the reboiling process into two independent parts: (1) vaporization of medium pressure carbon monoxide in the exchange line, and (2) reboiling in the dedicated reboiling column. This segmentation removes the coupling constraint where the exchange line had to simultaneously perform both vaporization and reboiling functions, allowing the system to operate at optimal efficiency for each function.

Inventive Principle:
Principle #1Segmentation

3Loss of energy

If medium pressure carbon monoxide is compressed to high pressure for reuse, then the reboiling needs are covered, but the medium pressure gas outlet on the compressor causes energy losses and operational inefficiencies

Engineering Contradiction:
Improveenergy lossVSAvoidoperational efficiency
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The invention extracts the reboiling function from the compression system by introducing a dedicated reboiling column with its own heating system. This eliminates the need to compress medium pressure carbon monoxide to high pressure for reboiling purposes. The compressor only needs to handle high pressure carbon monoxide from the synthesis loop, removing the inefficient intermediate compression and expansion steps.

Inventive Principle:
Principle #2Taking out (Extraction)

4Quantity of substance

If the exchange line is sized with large installed surface to vaporize required flow rate, then vaporization capacity is sufficient, but other fluids become too cold and the vaporized medium pressure carbon monoxide flow rate must be reduced

Engineering Contradiction:
Improvevaporized medium pressure carbon monoxide flow rateVSAvoidfluid temperature
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The invention extracts the reboiling function from the exchange line by introducing a dedicated reboiling column. This separates the vaporization function (performed by the exchange line) from the reboiling function (performed by the reboiling column), allowing each to be optimized independently. The exchange line can vaporize medium pressure carbon monoxide without being constrained by reboiling fraction limits, while the reboiling column provides the necessary reboiling capacity through its own heating system.

Inventive Principle:
Principle #2Taking out (Extraction)

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 energy losses and eliminates the need for medium pressure gas compression, enhancing the efficiency of carbon monoxide separation and reducing operational costs by allowing flexible reboiling without compromising the system's stability.

Implementation Method 1

A flow of high pressure carbon monoxide expanded in a valve is triggered in the bottom of the denitrogenation column

Methodology Applied
Scientific EffectJoule-Thomson effect: Joule-Thomson Effect

Implementation Method 2

The reboiling of the denitrogenation column is ensured by injecting carbon monoxide in the form of vapor into the column bottom

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 3

Method and device for separating a mixture containing at least hydrogen, nitrogen and carbon monoxide by cryogenic distillation

Methodology Applied
Scientific EffectCryogenic distillation: Distillation

Data Source

PatentEP2140216B1Method and device for separating a mixture containing at least hydrogen, nitrogen and carbon monoxide by cryogenic distillation
Publication Date: 2017.11.08 LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE
  • EP2140216B1 patent drawingFigure 1
  • EP2140216B1 patent drawing

AI summary

The invention relates to a method for separating a mixture containing carbon monoxide, nitrogen and hydrogen by cryogenic distillation in a separation means system including a denitrification column (C4) and at least another column, that comprises separating the mixture in order to obtain a fluid enriched with carbon monoxide and containing nitrogen, separating the fluid in the denitrification column, pressurising the carbon monoxide flow from the column system in a compressor (V1, V2) up to a high pressure, a fraction (7) of the carbon monoxide flow being used as a product, expanding a variable amount (57) of the high-pressure carbon monoxide flow cooled in a valve (59) before supplying it to the vat of the denitrification column, and varying the flow expanded in the valve according to the re-boiling needs of the denitrification column