Isothermal Methanation Reactor with Integrated Water Separation

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Solution Overview

Problem

Current methods for producing synthetic natural gas (SNG) through gasification of hydrocarbons face inefficiencies due to suboptimal H2/CO ratios, catalyst deactivation, and complex reactor designs, particularly in adiabatic and multi-stage processes that require additional separation steps for H2, CO2, and H2O to meet natural gas specifications.

Innovation Solution

An isothermal methanation reactor system with integrated water separation and recirculation of dehydrated synthetic natural gas, which adjusts the H2/CO ratio and eliminates the need for downstream separation of H2, utilizing a fluidized bed configuration with heat exchange surfaces to maintain optimal temperatures and simplify reactor design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If adiabatic methanation reactor is used, then reactor design is simpler, but temperature control is poor leading to catalyst deactivation and suboptimal H2/CO ratio

Engineering Contradiction:
Improvereactor design complexityVSAvoidcatalyst activity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the operating mode from adiabatic to isothermal by introducing external heat exchange surfaces (heat exchangers) that maintain constant temperature throughout the reactor. This parameter change enables better temperature control to prevent catalyst deactivation while managing the exothermic methanation reaction heat.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces heat exchange surfaces as intermediary elements between the reaction zone and the external environment. These heat exchangers act as mediators to transfer heat from the exothermic reaction, maintaining optimal temperature for catalyst activity without requiring complex internal cooling systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If multiple separation steps for H2, CO2, and H2O are implemented, then SNG specifications are met, but process complexity increases

Engineering Contradiction:
ImproveSNG specification complianceVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the methanation reaction with water separation by integrating heat exchange surfaces that serve dual purposes: maintaining isothermal conditions for the reaction and condensing water vapor from the gas stream. This combination reduces the need for separate water separation units.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat exchange surfaces perform multiple functions simultaneously: they control reaction temperature, condense water vapor, and can be configured to separate CO2 through selective permeation or absorption. This multi-functionality reduces the number of dedicated separation equipment needed.

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

3Productivity

If H2/CO ratio is not optimized, then gasification process is simpler, but methane production efficiency decreases

Engineering Contradiction:
Improvemethane production efficiencyVSAvoidgasification process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements feedback control by monitoring the H2/CO ratio in the syngas feed and adjusting the water-gas shift reaction conditions accordingly. The isothermal reactor with controlled steam injection allows dynamic adjustment to maintain optimal H2/CO ratio close to 3:1 for maximum methane production.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the gasification reaction conditions by introducing steam at controlled rates to promote the water-gas shift reaction (CO + H2O ⇔ H2 + CO2). This parameter change increases H2 production and optimizes the H2/CO ratio for subsequent methanation.

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 enables efficient single-stage methanation with improved Wobbe index and higher heating value, reducing the need for additional separation steps and simplifying the process, while maintaining catalyst activity and achieving SNG specifications compatible with natural gas distribution networks.

Implementation Method 1

a water separation means comprising: an inlet for natural syngas and an outlet for dehydrated natural syngas

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

utilizing a fluidized bed configuration with heat exchange surfaces to maintain optimal temperatures

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

utilizing a fluidized bed configuration with heat exchange surfaces to maintain optimal temperatures

Methodology Applied
Scientific EffectFluidization: Fluidisation

Implementation Method 4

catalytic methanation, which converts H2 and CO into CH4

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP3322778B1Apparatus and method for producing synthesis gas
Publication Date: 2020.03.25 GDF SUEZ SA
  • EP3322778B1 patent drawingFigure 1~2
  • EP3322778B1 patent drawingFigure 3
  • EP3322778B1 patent drawingFigure 4~7

AI summary

The invention relates to a synthetic gas production device (10) comprising: an isothermal methanation reactor (105) comprising: an inlet (110) which is intended for syngas produced by gasification of hydrocarbon material and is connected to a syngas supply channel (115) and an outlet (120) for synthetic natural gas; a water separation means (125) comprising: an inlet (130) for synthetic natural gas and an outlet (135) for dehydrated synthetic natural gas; and a bypass (140) for a portion of the dehydrated synthetic natural gas from the outlet of the water separation means to the syngas supply channel in order to supply a mixture of the bypassed syngas and synthetic natural gas to the reactor.