Fuel Cell Hydro-Desulfurizer Flow Control
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Solution Overview
Problem
Conventional fuel cell systems face issues when starting to supply recycled gas to the recycle passage after the warm-up of the hydro-desulfurizer is completed, leading to reduced power generation efficiency and increased start-up energy, as well as potential voltage reduction and durability issues due to temporary decreases in fuel utilization ratios.
Innovation Solution
A fuel cell system configuration that includes a reformer, fuel cell, hydro-desulfurizer, recycle passage, temperature detector, and controller, where the controller increases the flow rate of the raw material when the hydro-desulfurizer reaches a predetermined temperature and then starts supplying recycled gas to the recycle passage, subsequently returning the flow rate to normal after the gas reaches the upstream end, thereby maintaining optimal fuel utilization and power generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recycled gas is supplied to the recycle passage after the hydro-desulfurizer warm-up is completed, then the sulfur component removal performance is improved, but the power generation efficiency is reduced and start-up energy is increased
Solution Approach 1:
The controller increases the raw material flow rate before starting the recycled gas supply to the recycle passage. This preliminary action ensures that there is sufficient reformed gas available in the system when the recycled gas circulation begins, preventing any temporary decrease in fuel utilization ratio that would occur if the recycled gas were introduced without pre-positioning sufficient reformate in the system.
2Productivity
If the raw material flow rate is increased before recycled gas supply, then the fuel utilization ratio is maintained, but the raw material consumption is temporarily increased
Solution Approach 1:
The raw material flow rate is dynamically adjusted based on the operational state of the hydro-desulfurizer and the recycled gas supply status. The flow rate is increased temporarily only when needed (before and during the transition to recycled gas supply), and then returned to the normal set value once the recycled gas is fully integrated into the system, optimizing both fuel utilization and raw material consumption.
3Reliability
If the hydro-desulfurizer is heated and warmed up, then the sulfur component removal performance is improved, but the start-up energy is increased
Solution Approach 1:
The system maintains continuous power generation operation during the hydro-desulfurizer warm-up period by utilizing the reformer and fuel cell to generate electricity while the hydro-desulfurizer is being heated. This allows the sulfur removal function to be activated without interrupting the useful action of power generation, thereby reducing the net start-up energy requirement.
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 enhances power generation efficiency, reduces start-up energy, and minimizes voltage reduction and durability issues by maintaining optimal fuel utilization and flow rates during the transition to recycled gas supply.
Implementation Method 1
hydrodesulfurization in which the sulfur component is removed by adding hydrogen to the raw material
Implementation Method 2
The hydro-desulfurizer generates hydrogen sulfide from hydrogen and the sulfur component in the raw material supplied from an outside and causes the catalyst to chemically adsorb sulfur in the hydrogen sulfide
Implementation Method 3
normal temperature desulfurization in which the sulfur component is physically adsorbed on a catalyst at normal temperature to be removed
Implementation Method 4
a fuel cell reforms therein the raw material to generate a hydrogen-containing reformed gas
Implementation Method 5
the fuel cell can utilize hydrogen in the reformed gas and oxygen in air supplied from an outside to generate electricity and heat by an electric power generating reaction
Implementation Method 6
The raw material having passed through the reformer and the anode of the fuel cell or the reformed gas is combusted together with air supplied to a cathode of the fuel cell, and the hydro-desulfurizer, the reformer, and the fuel cell are heated and warmed up by heat of the combustion
Data Source
AI summary
A fuel cell system includes: a reformer generating a reformed gas using a raw material; a fuel cell generating electric power; a raw material supply passage; a hydro-desulfurizer operative to remove sulfur component in the raw material; a recycle passage through which the reformed gas is supplied to the raw material supply passage provided upstream of the hydro-desulfurizer; a temperature detector detecting a temperature of the hydro-desulfurizer; and a controller, wherein: when the temperature of the hydro-desulfurizer reaches a predetermined temperature, the controller increases a flow rate of the raw material from a predetermined flow rate by a flow rate corresponding to a flow rate of the recycled gas, and then, the controller starts supplying the recycled gas to the recycle passage; and after the recycled gas reaches an upstream end of the recycle passage, the controller returns the flow rate of the raw material to the predetermined flow rate.