Electrochemical Methane Conversion via Voltage-Controlled Oxidation

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Solution Overview

Problem

Current methods for directly converting low-cost gases like methane into valuable liquid fuels such as methanol are inefficient and prone to deep fuel oxidation, requiring high energy and challenging selectivity due to the strong C—H bonds in methane.

Innovation Solution

An electrochemical cell system using a metal oxide anode electrocatalyst, where a voltage-controlled oxygen ion flux oxidizes the anode to higher valency oxides, facilitating the conversion of methane to methanol or formaldehyde, with a lithiated composite cathode and doped cerium oxide electrolyte, enabling controlled oxidation and minimizing over-oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If high temperature and strong oxidant conditions are used to activate C-H bonds, then the oxidation reaction is driven by thermodynamics, but selectivity deteriorates and deep fuel oxidation occurs

Engineering Contradiction:

Improveoxidation reaction driveVSAvoidselectivity

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent changes the operating parameters from high temperature to intermediate temperature (600-900°C), and controls oxygen activity through electrochemical means rather than using strong oxidants. This parameter change allows the reaction to proceed with better selectivity while maintaining thermodynamic drive through electrochemical potential.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs electrochemical control where the oxygen activity at the anode surface is dynamically adjusted through applied voltage. This feedback mechanism allows precise control of oxidation extent, preventing over-oxidation while maintaining reaction drive through electrochemical potential adjustment.

Inventive Principle:

Principle #23Feedback

2Productivity

If conventional steam reformation is used to convert methane to synthesis gas, then conversion is achieved, but high temperature and pressure conditions are required making it unsuitable for low-scale wellheads

Engineering Contradiction:

Improvegas conversionVSAvoidprocess conditions

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces the thermal-mechanical steam reformation process with an electrochemical conversion process. Instead of using high temperature steam and mechanical pressure systems, the invention uses electrochemical cells with controlled oxygen ion flux to convert methane directly to liquid fuels at milder conditions suitable for portable applications.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If direct conversion methods are used to transform methane to liquid fuels, then the process is simplified, but the strong C-H bonds in methane make activation difficult requiring high energy input

Engineering Contradiction:

Improveprocess simplificationVSAvoidactivation energy

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent introduces metal oxide electrocatalysts as intermediaries that facilitate C-H bond activation. These catalysts provide alternative reaction pathways with lower activation energy requirements, enabling direct conversion of methane to liquid fuels without requiring excessive energy input while maintaining process simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 selectivity and yield in converting methane to methanol or formaldehyde, efficiently utilizing low-cost gases while avoiding deep oxidation, making it suitable for low-scale, portable, and cost-effective fuel production.

Implementation Method 1

an anode electrocatalyst is oxidized to higher valency oxides or a mixture of oxide phases, following a gas to fuels conversion, by supplying a voltage controlled oxygen ion flux to the anode

Methodology Applied

Scientific EffectElectrochemical oxidation: Oxidation

Implementation Method 2

oxygen ions transported through an electrolyte from the cathode to the anode

Methodology Applied

Scientific EffectIon transport through electrolyte: Electrolyte

Implementation Method 3

The anode electrocatalyst is partially oxidized by the oxygen ions transported through an electrolyte from the cathode to the anode. The method further includes supplying a feed gas stream to the anode electrocatalyst, wherein the feed gas stream is at least partially oxidized by the anode electrocatalyst

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS9879352B2Methods and systems for fuel production in electrochemical cells and reactors

Publication Date: 2018.01.30 BATTELLE MEMORIAL INST

AI summary

Methods and systems for fuel, chemical, and/or electricity production from electrochemical cells are disclosed. A voltage is applied between an anode and a cathode of an electrochemical cell. The anode includes a metal or metal oxide electrocatalyst. Oxygen is supplied to the cathode, producing oxygen ions. The anode electrocatalyst is at least partially oxidized by the oxygen ions transported through an electrolyte from the cathode to the anode. A feed gas stream is supplied to the anode electrocatalyst, which is converted to a liquid fuel. The anode electrocatalyst is re-oxidized to higher valency oxides, or a mixture of oxide phases, by supplying the oxygen ions to the anode. The re-oxidation by the ions is controlled or regulated by the amount of voltage applied.