Fuel Cell Exhaust Dehumidification for High-Purity Nitrogen
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Solution Overview
Problem
The challenge is to generate high-purity nitrogen gas reliably and stably using a fuel cell, as the exhaust gas from fuel cells contains a high amount of water vapor, which hinders subsequent purification treatments.
Innovation Solution
A nitrogen gas generation apparatus and system that include a fuel cell, a dehumidification mechanism to reduce moisture content, and a filtering mechanism using fibers with different permeation degrees for nitrogen and oxygen, which converts the exhaust gas into a gas with increased nitrogen concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If exhaust gas from fuel cell is used directly for nitrogen gas generation, then the process is simplified, but the high water vapor content hinders subsequent purification treatment
Solution Approach 1:
The patent applies preliminary dehumidification treatment to the exhaust gas before it enters the purification system. A dehumidifier is installed upstream to remove excess water vapor from the exhaust gas, ensuring that subsequent purification treatments can proceed reliably and stably without being hindered by high moisture content.
2Manufacturing precision
If conventional air separation methods are used, then high-purity nitrogen gas can be produced, but the process requires air as raw material and does not utilize fuel cell exhaust gas
Solution Approach 1:
The patent changes the raw material parameter from conventional air to fuel cell exhaust gas. By adjusting and optimizing the purification process parameters (including dehumidification, filtration, and oxygen removal), the system achieves high-purity nitrogen gas production while utilizing the unique composition of fuel cell exhaust gas, which has lower oxygen concentration than air.
3Reliability
If multiple purification stages are added to handle water vapor, then purification reliability improves, but device complexity increases
Solution Approach 1:
The patent performs dehumidification as a preliminary action before the main purification process. By removing excess water vapor upfront, the system prevents potential issues in subsequent purification stages, ensuring reliable operation without requiring overly complex multi-stage water removal systems.
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
The system efficiently generates high-purity nitrogen gas with a low oxygen concentration, achieving reliable and stable operation by effectively reducing water vapor content and oxygen levels in the exhaust gas.
Implementation Method 1
a filtering mechanism which includes a filter using fibers having different degrees of permeation for nitrogen and oxygen
Data Source
AI summary
An apparatus/system for generating a high-purity nitrogen gas using a fuel cell includes; a fuel cell that operates by taking in air or a gas containing nitrogen and oxygen, and a fuel gas; a dehumidification mechanism that reduces moisture or water vapor content in an exhaust gas that is extracted from the fuel cell and has a lower oxygen concentration than air; and a filtering mechanism which includes a filter using fibers having different degrees of permeation for nitrogen and oxygen and converts the exhaust gas having a reduced moisture or water vapor content into a gas having an increased nitrogen concentration. The filter recovery ratio is higher when an oxygen concentration of a gas to be filtered is lower. The dehumidification mechanism is a pump unit including a water seal pump to provide an adiabatic expansion chamber in which the exhaust gas extracted from the fuel cell expands adiabatically.