Hydrogen Generator Pipe Placement for Thermal Stress Reduction
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Solution Overview
Problem
Hydrogen generation devices face issues with thermal stress due to temperature expansion and contraction, leading to potential breakage of pipes and structural damage from thermal expansion during operation and cooling.
Innovation Solution
The hydrogen generation device design places all pipes in a low-temperature portion of the main body, with the support also located at this low-temperature area, reducing thermal stress. Additionally, a pipe orifice forming body connects pipes to the support, and a heat insulator is used between the main body and support to manage thermal expansion, preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the hydrogen generation device is operated at high temperature for steam reforming reaction, then the reforming reaction efficiency is improved, but thermal stress causes breakage of pipes and structural damage
Solution Approach 1:
The hydrogen generation device is divided into distinct temperature zones: a high-temperature zone for the steam reforming reaction and a low-temperature zone for pipe connections and support structures. This spatial segmentation allows the reactive portion to operate at high temperature while the structural portions remain at low temperature, preventing thermal stress damage.
Solution Approach 2:
A heat insulator is introduced as an intermediary between the high-temperature reforming section and the low-temperature support/pipe connection section. This heat insulator blocks thermal transmission, protecting the pipes and support structures from high temperature exposure while allowing the reforming reaction to proceed efficiently.
2Ease of operation
If pipes are connected to the main body during operation, then the device can function, but thermal expansion and contraction cause breakage of pipes and main body
Solution Approach 1:
Different portions of the device are assigned different thermal characteristics: the reforming chamber operates at high temperature while the pipe connection areas and support structures are maintained at low temperature through heat insulation. This local quality differentiation ensures that pipes and connections are not exposed to thermal expansion and contraction stresses.
Solution Approach 2:
The support structure and pipe connection points are pre-positioned in low-temperature zones before operation begins. The heat insulator is pre-installed to block thermal pathways, ensuring that when the device operates, the pipes and support structures remain thermally protected from the outset, preventing thermal stress-induced breakage.
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 effectively prevents breakage and deterioration of pipes and the main body due to thermal stress, enhancing the stability and longevity of the hydrogen generation device and fuel cell system.
Implementation Method 1
a heat insulator is used between the main body and support to manage thermal expansion, preventing damage
Implementation Method 2
thermal stress attributable to thermal expansion occurring during operation and cooling contraction occurring during a halt
Data Source
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AI summary
A hydrogen generation device or a fuel cell system of the present invention can prevent deterioration or breakage of portions of the hydrogen generation device, which is caused by thermal stress attributable to repeated operation and halt. Thus, it is possible to increase the life and enhance the stability of the device and the system. A hydrogen generation device 76 of a fuel cell system 100 includes a hydrogen generation device main body 78 including a combustor 4 provided therein for combusting a predetermined medium capable of generating hydrogen and a plurality of pipes which are connected to the hydrogen generation device main body 78 for allowing the predetermined medium flow into or out of the hydrogen generation device main body 78. A temperature gradient is formed in the hydrogen generation device main body 78 by operation of the combustor 4, whereby a high temperature portion and a low temperature portion are formed in the hydrogen generation device main body 78. All of the plurality of pipes are arranged in the low temperature portion. A support 70 supports the hydrogen generation device main body 78 from an outside of the low temperature portion.