Method for separating a synthesis gas

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Solution Overview

Problem

Cryogenic distillation apparatuses face instability and increased operating costs due to fluctuations in synthesis gas supply, leading to purity issues and prolonged shutdowns when operated at reduced loads, resulting in high non-production costs and disruptions to downstream customers.

Innovation Solution

Recycling gases produced by the cryogenic distillation apparatus upstream of the compressor and purification unit, including storing and reusing compressed synthesis gas to maintain a stable flow and ensure continuous CO production, even during syngas generation unit stoppages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the cryogenic distillation unit operates at low load to match customer demand, then operating costs are reduced, but operational stability deteriorates with increased risks of purity issues and production fluctuations

Engineering Contradiction:
Improveoperating costsVSAvoidoperational stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies preliminary action by recycling gases produced by the cryogenic distillation unit back to the synthesis gas compressor inlet. This ensures that even when the syngas generation unit is shut down or operating at low load, the cryogenic distillation unit receives sufficient feed gas flow to maintain stable operation and meet purity requirements, thereby resolving the contradiction between reduced operating costs and maintained operational stability.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the cryogenic distillation unit operates at high load to ensure stable operation, then operational stability is improved, but operating costs increase due to excessive feed rate requirements

Engineering Contradiction:
Improveoperational stabilityVSAvoidoperating costs
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies discarding and recovering by taking gases that would otherwise be discarded (produced by the cryogenic distillation unit) and recovering them by recycling back to the compressor inlet. This creates an additional feed source that allows the unit to operate at lower loads while maintaining stability, thus reducing operating costs without sacrificing operational reliability.

Inventive Principle:
Principle #34Discarding and recovering

3Adaptability or versatility

If the syngas generation unit shuts down, then production flexibility is improved, but the cryogenic distillation unit must stop causing prolonged CO2 production interruptions

Engineering Contradiction:
Improveproduction flexibilityVSAvoidshutdown duration
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies continuity of useful action by establishing a recycling loop that maintains continuous gas flow to the cryogenic distillation unit even when the syngas generation unit is shut down. The recycled gases sustain the distillation process, allowing CO2 production to continue without interruption and eliminating the need for prolonged shutdowns, thus resolving the contradiction between production flexibility and shutdown duration.

Inventive Principle:
Principle #20Continuity of useful action

4Reliability

If the cryogenic distillation unit requires sufficient feed rate for stable operation, then operational stability is improved, but excess CO and H2 are produced increasing operating costs and flaring requirements

Engineering Contradiction:
Improveoperational stabilityVSAvoidexcess CO and H2
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies universality by making the recycled gases serve multiple functions: they maintain the minimum feed rate required for cryogenic distillation unit stability, and simultaneously act as a sink for excess CO and H2 that would otherwise need to be flared. This multi-functional use of the recycling loop resolves the contradiction between operational stability and reduction of substance loss.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 total costs, eliminates the need for shutdowns and recompression, and ensures continuous CO production by maintaining a sufficient flow to the cryogenic distillation apparatus, thereby improving reliability and minimizing supply disruptions to customers.

Implementation Method 1

a cryogenic distillation unit and an adsorption unit are generally used. The cryogenic distillation unit purifies the CO and produces a hydrogen-enriched stream

Methodology Applied
Scientific EffectCryogenic distillation: Distillation

Implementation Method 2

The synthesis gas exiting the generator is cooled (for steam production and various preheating processes)

Methodology Applied
Scientific EffectCryogenics: Cryogenics

Implementation Method 3

which is then purified of hydrogen by adsorption

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 4

The synthesis gas is compressed with a compressor upstream of the cryogenic distillation unit

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3488165B1Method for separating a synthesis gas
Publication Date: 2021.12.01 LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE
  • EP3488165B1 patent drawingFigure 1
  • EP3488165B1 patent drawingFigure 2
  • EP3488165B1 patent drawingFigure 3

AI summary

In a method for separating a synthesis gas (1) containing carbon monoxide and hydrogen, a synthesis gas (1) flow from a synthesis gas source is compressed in a compressor (3) and separated into at least three gaseous products. If there is insufficient synthesis gas, at least three separation products are recycled in the compressor in order to separate said products.