Methanation Reactor Buffer Recycling for Gas Quality

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Solution Overview

Problem

Methanation processes face inefficiencies during transitions between operating modes, resulting in the production of 'bad gas' that does not meet quality criteria, which is typically flared off, despite containing usable residual value, especially with frequent switching due to intermittent hydrogen availability.

Innovation Solution

Recycling of 'bad gas' is implemented by at least partial recirculation to a process step before methanation, with delayed intermediate storage and conditioning to match desired compositions, allowing for variable configuration and avoiding 'hot spots' in the reactor, and utilizing the gas in subsequent operating modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the methanation reactor is operated intermittently due to hydrogen availability, then the process adapts to energy supply conditions, but gas losses increase due to flaring of bad gas during transitions

Engineering Contradiction:

Improveadaptability to hydrogen availabilityVSAvoidgas losses

Core Design Contradiction:

Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The patent converts the harmful effect of bad gas flaring into a beneficial recycling process. During transition phases when quality criteria are not met, the gas is diverted to a buffer volume instead of being flared, then recycled to the educt gas inlet when quality is restored, transforming waste into reusable feedstock

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system temporarily discards bad gas by diverting it to a buffer volume during transition phases, then recovers it by recycling the buffered gas back to the educt gas inlet once the methanation process stabilizes and produces quality-compliant product gas

Inventive Principle:

Principle #34Discarding and recovering

2Productivity

If the methanation reactor is frequently switched between operating modes, then the process responds to energy availability changes, but manufacturing precision deteriorates due to quality criterion violations during transitions

Engineering Contradiction:

Improveresponse to energy availabilityVSAvoidgas composition quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The buffer volume acts as an intermediary between the methanation reactor and the product gas outlet. During transition phases when gas quality is compromised, the buffer absorbs these intermediate products, preventing them from contaminating the final product stream and maintaining consistent product quality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary action by buffering and recycling gas during transition phases before it can degrade product quality. This preparatory measure ensures that only quality-compliant gas is delivered to the product outlet, maintaining manufacturing precision

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If bad gas is flared off conventionally, then the process simplifies operation, but loss of energy increases due to disposal of usable residual value

Engineering Contradiction:

Improveoperational simplicityVSAvoidenergy waste

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

Instead of flaring off bad gas and wasting its energy content, the system captures and recycles it to the educt gas inlet, converting what would be waste into a useful resource that contributes to the methanation process

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system implements a feedback loop where product gas quality is continuously monitored, and when quality criteria are not met, the gas is automatically diverted to the buffer and recycled back to the educt gas inlet, creating a self-correcting system that minimizes energy waste

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 enhances the utilization of previously unusable 'bad gas', maintaining consistent methanation process parameters and reducing gas losses, while ensuring the quality of the product gas meets the required criteria, even during transitions and low energy availability.

Implementation Method 1

a reactant gas containing hydrogen and carbon dioxide is methanated catalytically to form a gas mixture which meets a specified quality criterion relating to its gas composition

Methodology Applied

Scientific EffectCatalytic methanation: Catalysis

Data Source

PatentEP2595942B2Method for providing a methane-rich product gas, and an arrangement which is suitable for this purpose

Publication Date: 2017.03.01 ETOGAS

AI summary

The invention relates to a method for providing a methane-rich product gas. In a first operating mode, a reactant gas which has hydrogen and carbon dioxide is catalytically methanated into a gas mixture which satisfies a specified quality criterion relating to the gas mixture composition and which is provided as the product gas. In a second operating mode, the catalytic methanation is reduced, in particular stopped, by reducing, in particular cutting off, the reactant gas feed. A transition between the two operating modes is carried out dependent on an availability of the hydrogen. A gas mixture which is produced upon the transition and which does not satisfy the quality criterion is at least partly recycled as part of the providing method. The invention also relates to an arrangement which is suitable for carrying out the method.