Fuel Cell System Combustion Exhaust Gas Cascade Heating
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Solution Overview
Problem
In solid oxide fuel cell systems, the combustion heat generated is not efficiently utilized for heating the evaporator and desulfurizer, leading to excessive heating of the evaporator and inefficient use of thermal energy.
Innovation Solution
A fuel cell system design where combustion exhaust gas is used to heat the reformer, first cathode air heating part, desulfurizer, and evaporator in a cascading manner, optimizing the thermal energy usage by directing the combustion exhaust gas from higher to lower temperature devices, thereby reducing fuel consumption and improving electric power generation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If combustion heat is used to heat the desulfurizer first, then the evaporator, then the evaporator is heated to a temperature much higher than suitable for its operation
Solution Approach 1:
The heating process is segmented into distinct stages: first heating the desulfurizer to its required temperature, then heating the evaporator to its suitable operating temperature. This segmentation allows each component to receive appropriate heat treatment without excessive temperature exposure.
Solution Approach 2:
The system dynamically adjusts the heat transfer process by controlling the timing and extent of heat exposure to each component. The evaporator is heated only after the desulfurizer reaches its target temperature, and only to the extent required for its operation, preventing energy waste from overheating.
2Productivity
If combustion heat is supplied directly to the evaporator, then the evaporator can be heated efficiently, but the desulfurizer cannot reach its required operation temperature
Solution Approach 1:
The desulfurizer is heated first to its required temperature before the evaporator heating process begins. This preliminary action ensures that the desulfurizer reaches its operational temperature threshold, enabling it to function properly before the evaporator receives heat treatment.
Solution Approach 2:
The heating process continues in a continuous sequence: first the desulfurizer is heated to its target temperature, then the evaporator is heated to its suitable operating temperature. This continuous useful action ensures both components reach their required temperatures without interruption or energy waste.
3Loss of energy
If combustion heat is used to heat multiple components simultaneously, then energy utilization improves, but temperature control for each component becomes difficult
Solution Approach 1:
The simultaneous heating of multiple components is segmented into sequential stages. The desulfurizer is heated first to its required temperature, then the evaporator is heated to its suitable operating temperature. This segmentation maintains effective energy utilization while enabling precise temperature control for each component.
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 design effectively utilizes combustion heat in a cascade fashion, reducing fuel consumption and enhancing the electric power generation efficiency by ensuring optimal temperature management across the fuel cell system components.
Implementation Method 1
a combustor where a mixture of oxygen and gas which is contained in fuel is combusted
Implementation Method 2
a reformer for generating a reformed gas to be used as the fuel through a reforming reaction from a supplied fuel using a combustion exhaust gas generated in the combustor as a heat source
Implementation Method 3
a fuel cell for generating electric power through a reaction of the reformed gas and an oxidation gas
Implementation Method 4
a first cathode air heating part for heating the oxidation gas to be supplied to the fuel cell using the combustion exhaust gas which has heated the reformer as a heat source
Implementation Method 5
a desulfurizer for removing a sulfur ingredient contained in the fuel to be supplied to the reformer using the combustion exhaust gas which has heated the first cathode air heating part as a heat source
Implementation Method 6
an evaporator for generating water vapor to be supplied to the reformer by evaporating a supplied water using the combustion exhaust gas which has heated the desulfurizer as a heat source
Data Source
AI summary
The present invention provides a fuel cell system using combustion heat for an evaporator and a desulfurizer effectively. The fuel cell system comprises a combustor, a reformer, a fuel cell, a first cathode air heating part, a desulfurizer and an evaporator. A mixture of oxygen and gas which is contained in fuel is combusted in the combustor. A combustion exhaust gas generated in the combustor flows in the fuel cell system in such a manner that the combustion exhaust gas gives thermal energy to the reformer, the first cathode air heating part, the desulfurizer, and the evaporator in this order.