Fuel Cell-Engine Hybrid System for Exhaust Energy Recovery
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Solution Overview
Problem
Conventional fuel cell systems fail to effectively utilize exhaust gases discharged during electricity generation, leading to inefficiencies and reduced power output.
Innovation Solution
A fuel cell-engine hybrid system that includes an engine unit connected to the fuel cell to utilize exhaust gases, with a cooling unit to condense water vapor and a carbon dioxide capturing unit, and an air separating unit to supply oxygen for efficient combustion, utilizing a HCCI engine and turbocharger for enhanced power generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If exhaust gas is directly discharged from the fuel cell anode, then the fuel cell system is simple in structure, but the system efficiency deteriorates due to wasted energy in the exhaust gas
Solution Approach 1:
The patent merges the fuel cell system with an engine system to form a hybrid configuration. The exhaust gas from the fuel cell anode is directed to the engine as fuel, combining two power generation systems into one integrated unit that recovers energy that would otherwise be wasted.
Solution Approach 2:
The patent converts the harmful waste heat and unused chemical energy in the exhaust gas into useful power by feeding it to the engine. The exhaust gas, which was previously discarded, becomes a valuable fuel source for additional power generation.
2Reliability
If water vapor is not removed from exhaust gas, then the system operates continuously without interruption, but the HCCI engine cannot operate properly due to water vapor interference with combustion
Solution Approach 1:
The patent utilizes phase transition by cooling the exhaust gas to condense water vapor from the gaseous phase to liquid phase, which is then separated and removed from the exhaust stream before it enters the HCCI engine.
Solution Approach 2:
The exhaust gas is pre-treated by cooling and water vapor removal before being supplied to the HCCI engine, ensuring that the combustion process is not interfered with by water vapor while maintaining continuous operation.
3Productivity
If air is used as oxidant for the engine, then the system is simple, but the nitrogen in air reduces combustion efficiency and increases exhaust volume
Solution Approach 1:
The patent extracts only the oxygen component from air using an air separation unit, removing the nitrogen and other inert gases that would interfere with combustion. This purified oxygen is then supplied to the HCCI engine for more efficient combustion.
Solution Approach 2:
The patent uses pure oxygen instead of air as the oxidant, providing a stronger and more concentrated oxidizing environment that accelerates combustion and improves power generation efficiency from the exhaust gas fuel.
4Power
If the engine size is increased to generate more power from exhaust gas, then additional power is produced, but the system cost and complexity increase
Solution Approach 1:
The patent changes the composition parameters of the fuel by removing water vapor from the exhaust gas before it enters the HCCI engine. This parameter change increases the energy density and combustion efficiency of the fuel, allowing a smaller engine to produce the same power output.
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
Improves electric generation efficiency by utilizing exhaust gases, reduces engine size and cost, and enhances engine efficiency by eliminating water vapor and increasing oxidant concentration, allowing for additional power generation without additional fuel injection.
Implementation Method 1
The cooling unit may cool the exhaust gas down to a dew point of water vapor such that the water vapor included in the exhaust gas can be condensed therefrom
Implementation Method 2
a fuel cell refers to a system that continuously generates electricity by supplying fuel and oxidizing agent to an anode and a cathode
Implementation Method 3
an engine unit connected to a rear end of the electricity generating unit and generating power by receiving the exhaust gas discharged from the anode
Data Source
AI summary
The present invention relates to a fuel cell-engine hybrid system formed to effectively utilize an exhaust gas discharged from a process for generating electricity. A fuel cell-engine hybrid system according to the present invention includes: an electricity generating unit including a cathode and an anode interposing an electrolyte membrane therebetween; and an engine unit connected to a rear end of the electricity generating unit and generating power by receiving the exhaust gas discharged from the anode.