High-Temperature Desulfurization Reactor for SOFC Fuel

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Solution Overview

Problem

Fuel cell systems, such as solid oxide fuel cell (SOFC) systems, face reliability issues due to contaminants like sulfur species in the fuel stream, which can degrade performance and cause irreversible damage, and existing desulfurization sorbent beds have a finite life and are costly to replace.

Innovation Solution

A high-temperature desulfurization subsystem using a sulfur adsorption reactor with metal oxides, such as zinc oxide, that adsorbs sulfur species at temperatures ranging from 200° C. to 450° C., utilizing heat generated in the fuel cell system to maintain optimal adsorption efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional desulfurization sorbent beds are used to remove sulfur from fuel, then sulfur removal is achieved, but the sorbent beds have finite life and require frequent replacement increasing operational costs

Engineering Contradiction:

Improvedesulfurization effectivenessVSAvoidsorbent bed service life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the operating temperature parameter from conventional low temperatures to high temperatures (200-450°C), which fundamentally alters the adsorption characteristics of metal oxides toward sulfur species. This parameter change enables the desulfurization bed to maintain effectiveness indefinitely through continuous high-temperature operation, eliminating the finite service life issue of conventional sorbent beds

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs metal oxide materials (such as zinc oxide, copper oxide, or their combinations) as the active desulfurizing component. These metal oxide-based composite materials exhibit superior thermal stability and continuous sulfur adsorption capability at high temperatures, replacing conventional organic-based sorbents with limited service life

Inventive Principle:

Principle #40Composite materials

2Reliability

If sorbent beds are replaced prior to exhaustion to ensure continuous sulfur removal, then fuel cell protection is maintained, but underutilized portions of the sorbent bed increase replacement costs

Engineering Contradiction:

Improvefuel cell protectionVSAvoidsorbent material utilization

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The high-temperature desulfurization system operates continuously at 200-450°C, enabling the metal oxide sorbent to maintain constant sulfur adsorption capacity throughout its service life. The system's self-sustaining high-temperature operation ensures complete utilization of the sorbent material until genuine exhaustion, eliminating premature replacement and associated waste

Inventive Principle:

Principle #25Self-service

3Reliability

If heat is applied to the desulfurization reactor to maintain optimal adsorption temperature, then sulfur adsorption efficiency is improved, but additional energy consumption occurs

Engineering Contradiction:

Improvesulfur adsorption efficiencyVSAvoidheating energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent integrates the desulfurization reactor with the fuel cell system's existing thermal infrastructure. The reactor is positioned to receive waste heat from the fuel cell operation, merging the desulfurization function with the thermal management system. This combination allows the desulfurization reactor to reach and maintain optimal adsorption temperatures (200-450°C) using otherwise wasted thermal energy, eliminating additional energy consumption

Inventive Principle:

Principle #5Merging (Combining)

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

The subsystem effectively extends the service life of desulfurization beds, reduces replacement costs, and maintains fuel cell performance by continuously removing sulfur species, potentially eliminating the need for frequent replacements.

Implementation Method 1

a sulfur adsorption reactor comprising a metal oxide configured to adsorb sulfur species from fuel

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

heating the reactor to an operating temperature ranging from about 200° C. to about 450° C., using heat generated in the hot box

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentUS10847824B2Fuel cell system including high-temperature desulfurization subsystem and method of operating the same

Publication Date: 2020.11.24 BLOOM ENERGY CORP

AI summary

A fuel cell system includes a hot box, a stack of fuel cells disposed in the hot box, and a desulfurization subsystem. The desulfurization subsystem may include a sulfur adsorption reactor containing a metal oxide, such as ZnO, configured to adsorb sulfur species from fuel, a first fuel conduit configured to provide fuel to the reactor, and a second fuel conduit configured to receive fuel from the reactor. The desulfurization subsystem may be configured to heat the reactor to an operating temperature ranging from about 200° C. to about 450° C., using heat generated in the hot box.