Hydrogen Generator Heat Buffer for CO Reducer Temperature Control
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Solution Overview
Problem
The existing hydrogen generator experiences significant temperature variations in the thickness direction of the carbon monoxide reducer, leading to insufficient carbon monoxide removal due to suboptimal temperatures, which can impair the catalyst's functionality and reduce the efficiency of the fuel cell system.
Innovation Solution
A hydrogen generator design incorporating a heat transmission buffering section between the carbon monoxide reducer and the preheat-evaporator to mitigate cooling and maintain a more uniform temperature distribution, allowing for effective heat recovery and stabilization of the carbon monoxide removal process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If heat exchange is performed between water and heat generated in the CO shift converter to improve heat recovery efficiency, then heat recovery efficiency is improved, but temperature distribution in the thickness direction of the CO reducer becomes non-uniform
Solution Approach 1:
The CO reducer is divided into multiple sections along the flow direction, with heat exchange structures arranged at different positions. This segmentation allows different regions to have optimized heat exchange characteristics, preventing excessive cooling in any single location while maintaining overall heat recovery efficiency.
Solution Approach 2:
Heat exchange structures are selectively positioned at specific locations within the CO reducer where they are most effective. The density and configuration of heat exchange elements vary locally to match the temperature and flow characteristics at each position, ensuring uniform temperature distribution while maximizing heat recovery.
2Loss of energy
If the CO reducer is cooled by water during heat exchange to recover heat, then heat recovery is improved, but carbon monoxide removal becomes insufficient due to suboptimal temperatures
Solution Approach 1:
Heat exchange structures are positioned upstream in the CO reducer to pre-cool the gas before it reaches the main catalytic reaction zone. This preliminary cooling action allows the downstream regions to maintain higher temperatures necessary for effective CO removal, while still achieving overall heat recovery.
Solution Approach 2:
A heat transfer medium or intermediate structure is introduced to facilitate heat exchange without directly cooling the catalytic bed to harmful levels. This intermediary allows controlled heat extraction while maintaining the temperature conditions necessary for catalyst functionality and CO removal efficiency.
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 stabilizes carbon monoxide removal by reducing temperature variations in the carbon monoxide reducer, ensuring efficient operation and extending the lifespan of the fuel cell system by preventing catalyst poisoning from carbon monoxide.
Implementation Method 1
a shift converter for removing carbon monoxide up to about 0.5% through a CO shift reaction using a shifting catalyst
Implementation Method 2
a selective oxidizer for further removing carbon monoxide through a selective oxidization reaction using a selective oxidizing catalyst to reduce the CO concentration to about 10 ppm or less
Implementation Method 3
heat exchange is performed between water and heat generated in the CO shift converter and the selective oxidation reactor which perform an exothermic reaction
Implementation Method 4
The reformer uses hydrocarbon-based fuel such as city gas and LPG as a material gas and generates reformed gas containing hydrogen, methane, carbon monoxide (about 10%), carbon dioxide and steam, through a steam reforming reaction of the material gas and the water
Data Source
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AI summary
A hydrogen generator according to the invent ion comprises: a combustion gas passage (5) configured to flow combustion gas coming from a combustor; a preheat-evaporator (6) which is supplied with a material gas and water and configured to evaporate the water and heat the material gas by heat transmitted from the combustion gas passage and a carbon monoxide reducer (10) through partition a wall; a reformer (7) configured to generate reformed gas from the material gas and steam fed from the preheat-evaporator by using a reforming catalyst (8) and heat transmitted from the combustion gas passage through the partition wall; the carbon monoxide reducer (10) configured to remove carbon monoxide from the reformed gas fed from the reformer by a carbon monoxide removing catalyst (9); a cylindrical body (3) closed at both ends thereof having an internal space is divided by the partition walls (1), (2), (30), (47) to form the combustion gas passage, preheat-evaporator, reformer and carbon monoxide reducer within the cylindrical body (3), wherein a heat transmission buffering section (11) is formed between the preheat-evaporator and the carbon monoxide reducer such that the partition wall (30) that defines the preheat-evaporator and the partition wall (47) that defines the carbon monoxide reducer are opposed to each other with a space therebetween.