Fuel Cell Desulfurizer Temperature Segmentation for Water Vapor Interference

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Solution Overview

Problem

Existing fuel cell systems with desulfurization units using porous materials like zeolite or activated carbon face reduced sulfur adsorption capacity and shortened lifespan due to water vapor, especially when dealing with source gases of varying dew points, leading to increased costs and inefficiencies.

Innovation Solution

A fuel cell system design where the desulfurizing agent, comprising zeolite or activated carbon, operates at a temperature range of 50 °C to 200 °C, minimizing water vapor adsorption and thus maintaining sulfur compound adsorption capacity and extending the agent's lifespan, with a configuration that allows the source gas to be desulfurized effectively regardless of dew point variations by using a first desulfurizer at high temperature and a second desulfurizer at normal temperature in series or parallel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a normal-temperature desulfurizing agent (porous material like zeolite or activated carbon) is used to desulfurize source gas, then the sulfur compounds can be adsorbed and removed, but the desulfurizing agent preferentially adsorbs water vapor when the source gas has a high dew point and large water vapor volume, causing drastic decrease in sulfur adsorption capacity and deterioration of desulfurization effect

Engineering Contradiction:
Improvesulfur adsorption capacityVSAvoidwater vapor interference
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The desulfurization process is divided into two separate stages: a normal-temperature desulfurizer for removing sulfur compounds under low water vapor conditions, and a high-temperature desulfurizer for handling high dew point gases with large water vapor volumes. This segmentation allows each desulfurizer to operate in its optimal temperature range, preventing water vapor from competing for adsorption sites in the normal-temperature unit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the operating temperature parameter of the desulfurizing agent based on the dew point of the source gas. When the dew point is high (indicating large water vapor volume), the system switches to high-temperature operation (50-200°C) where water vapor adsorption is minimized. When the dew point is low, normal temperature operation is used for effective sulfur adsorption.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the normal-temperature desulfurizing agent adsorbs water vapor preferentially, then the sulfur adsorption capacity decreases drastically, but increasing the use amount of the desulfurizing agent to maintain desulfurization effect results in cost increase and enlargement of the fuel cell system

Engineering Contradiction:
Improvedesulfurization effectVSAvoidsystem size and cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system is segmented into two desulfurizers with different temperature operating ranges. The high-temperature desulfurizer handles cases with high dew point source gas, preventing water vapor from saturating the normal-temperature desulfurizer. This segmentation ensures reliable desulfurization without needing to oversized the normal-temperature desulfurizing agent.

Inventive Principle:
Principle #1Segmentation

3Quantity of substance

If the normal-temperature desulfurizing agent is used with source gas having high dew point and large water vapor volume, then the desulfurization effect deteriorates, but operating at high temperature (50-200°C) minimizes water vapor adsorption and maintains sulfur adsorption capacity

Engineering Contradiction:
Improvesulfur adsorption capacityVSAvoidoperating temperature
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The operating temperature of the desulfurizing agent is changed from normal temperature to high temperature (50-200°C) when the source gas has a high dew point. This parameter change reduces the affinity of the porous material for water vapor while maintaining sulfur compound adsorption capacity, solving the problem of water vapor interference.

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 configuration ensures efficient desulfurization of source gases with both low and high dew points, minimizing the use of desulfurizing agents, reducing costs, and prolonging their lifespan by optimizing temperature settings and flow directions within the desulfurization unit.

Implementation Method 1

A desulfurizing agent for the first desulfurizer is utilized at normal temperature to adsorb odorous sulfur compounds such as tertiary-butylmercaptan (TBM), dimethyl sulfide (DMS), and the like that are included in a city gas

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

the normal-temperature desulfurizing agent may preferentially adsorb the water vapor to sulfur compounds of the source gas. As a result, the sulfur adsorption capacity of the normal-temperature desulfurizing agent may drastically decrease

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP2487741B1Fuel cell system and desulfurization unit for the same
Publication Date: 2018.08.01 AISIN SEIKI KK
  • EP2487741B1 patent drawingFigure 1
  • EP2487741B1 patent drawingFigure 2A~2B
  • EP2487741B1 patent drawingFigure 3~4

AI summary

A desulfurization unit for a fuel cell system (400) includes a first desulfurizer (100) arranged in a temperature environment ranging from 50 °C to 200 °C and accommodating a desulfurizing agent including a porous material serving as a base material, the desulfurizing agent exerting a desulfurization effect in a normal temperature range, the first desulfurizer (100) adsorbing a sulfur compound included in a source gas in the temperature environment ranging from 50 °C to 200 °C when the source gas having a low dew point is supplied through a source gas passage (500) to the first desulfurizer (100) and when the source gas having a high dew point is supplied through the source gas passage (500) to the first desulfurizer (100).