Fuel Cell Gas Liquid Separator Design for Freezing Prevention

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Solution Overview

Problem

Fuel cell systems face issues with water freezing in the gas and liquid separator, leading to inefficient drainage and potential turbine damage due to water discharge with exhaust gas, especially in cold conditions.

Innovation Solution

A gas and liquid separator design featuring a first separating portion for anode exhaust gas, a first container with a storage reservoir, a second container for cathode exhaust gas, and a valve apparatus that stores and discharges water separately from the exhaust gas, utilizing heat from the cathode exhaust gas to prevent freezing and ensure controlled water discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gas and liquid separator is arranged in the off-gas discharge pipe to utilize heat from off-gas, then the freezing of produced water is prevented, but the produced water may be discharged together with exhaust gas causing road surface slipperiness and turbine damage

Engineering Contradiction:

Improveprevention of water freezingVSAvoidwater discharge with exhaust gas

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The gas and liquid separator is divided into two separate containers: a first container for anode exhaust gas and a second container for cathode exhaust gas. This segmentation allows independent control of water discharge from each container, preventing water from being discharged with either exhaust stream while maintaining heating functions in both containers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The water discharge function is extracted from the exhaust gas flow path. A separate water discharge passage is provided that allows water to be discharged independently from the exhaust gas, preventing water from being released together with the exhaust gas while still utilizing the heating effect of the exhaust gas on the water storage reservoir.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If the discharge valve and actuating equipment are arranged in the off-gas discharge pipe, then quick unfreezing is achieved during fuel cell start-up, but the device complexity increases

Engineering Contradiction:

Improvequick unfreezing capabilityVSAvoidvalve apparatus arrangement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The discharge valve and actuating equipment are merged into a single integrated valve apparatus unit. The actuating equipment is positioned adjacent to the discharge valve, allowing compact arrangement that reduces device complexity while maintaining the quick unfreezing capability through efficient heat utilization from the exhaust gas.

Inventive Principle:

Principle #5Merging (Combining)

3Quantity of substance

If produced water is discharged into the off-gas pipe for release to outside, then water storage capacity is utilized, but road surface slipperiness increases due to freeze and turbine may fail

Engineering Contradiction:

Improvewater storage and dischargeVSAvoidroad surface slipperiness and turbine failure

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

A separate water discharge passage acts as an intermediary between the water storage reservoir and the external environment. This intermediary pathway allows water to be discharged independently from the exhaust gas flow, preventing water from being released with the exhaust gas while still enabling effective water discharge from the storage reservoir.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Inventive Principle:

Principle #2Taking out (Extraction)

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

Prevents water from freezing and discharging with exhaust gas, reducing the risk of turbine damage and ensuring reliable operation by using the cathode exhaust gas heat to maintain the water in a flowable state and separate its discharge from the exhaust flow.

Implementation Method 1

facilitating heat transmission from the off-gas to the bottom portion of equipment of the gas and liquid separator, to the produced water discharge passage, and to the discharge valve

Methodology Applied

Scientific EffectHeat transmission: Conduction (thermal)

Implementation Method 2

water discharged from the first storage reservoir is stored in the second storage reservoir

Methodology Applied

Scientific EffectThermal energy storage: Thermal Energy Storage

Implementation Method 3

a first separating portion configured to separate a liquid droplet from a first exhaust gas discharged from a negative electrode of a fuel cell

Methodology Applied

Scientific EffectPhase separation: Phase Change

Implementation Method 4

a first storage reservoir provided at a lower portion of the first container and storing water flowing down from the first separating portion

Methodology Applied

Scientific EffectGravitational settling: Gravitation

Data Source

PatentUS11588160B2Fuel cell gas/liquid separator including first container for negative electrode exhaust and second container for positive electrode exhaust

Publication Date: 2023.02.21 AISIN CORP

AI summary

A gas and liquid separator includes a first separating portion configured to separate a liquid droplet from a first exhaust gas discharged from a negative electrode of a fuel cell, a first container accommodating the first separating portion, a first storage reservoir storing water flowing down from the first separating portion, a second container provided at a lower side of the first storage reservoir, a second storage reservoir provided at a lower portion of the second container, and a valve apparatus including a valve discharging water stored in the first storage reservoir, wherein a second exhaust gas discharged from a positive electrode flows in the second container, and water discharged from the first storage reservoir is stored in the second storage reservoir.