Unitized Hydrodesulfurizer Heat Exchanger Assembly

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Solution Overview

Problem

Conventional fuel cell power plant systems do not sufficiently heat the raw fuel and hydrogen mixture to achieve maximum catalytic conversion of organic sulfur compounds to hydrogen sulfide, due to inadequate thermal contact between the annular heat exchanger and hydrodesulfurizer.

Innovation Solution

A unitized assembly with spiral flow paths created by spiral rods in contact with the outer wall of the heat exchanger, allowing for enhanced thermal exchange and increased temperature of the fuel-hydrogen mixture before entering the hydrodesulfurizer, while maintaining easy assembly by providing a 6 mm clearance between the hydrodesulfurizer and the thin shell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple annular passage is used for the fuel-hydrogen mixture, then the device complexity is reduced, but the thermal contact between the heat exchanger and hydrodesulfurizer is insufficient

Engineering Contradiction:
Improvestructure complexityVSAvoidthermal contact efficiency
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The annular passage is segmented into multiple spiral flow paths by inserting spiral rods, dividing the single continuous flow into multiple parallel spiral trajectories that increase thermal contact area between the heated outer wall and the fuel-hydrogen mixture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flow path transitions from a simple two-dimensional annular passage to a three-dimensional spiral configuration, utilizing the radial and axial dimensions to create extended contact paths between the heating surface and the flowing mixture

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Temperature

If the hydrodesulfurizer is placed close to the heat exchanger for thermal coupling, then the thermal exchange efficiency is improved, but the assembly becomes difficult

Engineering Contradiction:
Improvethermal exchange efficiencyVSAvoidassembly ease
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

A thin shell is introduced as an intermediary component between the spiral rods and the hydrodesulfurizer inner wall, providing a standardized interface that facilitates assembly while maintaining the necessary thermal coupling through the shell material

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If the spiral rods are inserted into the hydrodesulfurizer, then the thermal contact area is increased, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvethermal contact areaVSAvoidinsertion precision
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The insertion process is segmented into sequential steps: first inserting the spiral rods through the top cover, then installing the thin shell, and finally positioning the hydrodesulfurizer inner wall, allowing each component to be manufactured and assembled separately with standard tolerances

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The thin shell serves as a precision intermediary that bridges the spiral rods and the hydrodesulfurizer inner wall, absorbing dimensional variations and ensuring proper thermal contact without requiring extremely tight tolerances on the individual components

Inventive Principle:
Principle #24Intermediary (Mediator)

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 assembly effectively raises the temperature of the fuel-hydrogen mixture to the optimal catalytic conversion temperature, ensuring efficient conversion of organic sulfur compounds to hydrogen sulfide and subsequent absorption, while maintaining a compact and easily assembled design.

Implementation Method 1

spiral rods in contact with the outer wall of the heat exchanger

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

spiral flow paths have been established by means of a plurality of spiral rods in contact with the outer wall of the heat exchanger

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

the hydrocarbon is treated catalytically in the presence of hydrogen to effect a conversion of the organic sulfur compounds to inorganic compounds

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 4

the temperature of the natural gas stream entering the hydrodesulfurizing bed must be elevated to a temperature which best promotes the catalytic conversion of sulfur and sulfur compounds to hydrogen sulfide

Methodology Applied
Scientific EffectThermal energy: Heating

Implementation Method 5

which are subsequently removed by absorption

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP2448660B1A unitized hydrodesulfurizer, heat exchanger and shift converter assembly and method of forming the same
Publication Date: 2019.08.14 DOOSAN FUEL CELL AMERICA INC
  • EP2448660B1 patent drawingFigure 1
  • EP2448660B1 patent drawingFigure 2~3

AI summary

A cylindrical shift converter (4) is disposed within an annular heat exchanger (28, 24) which has an outer wall (5). A plurality of spiral rods (90) create a plurality of spiral gas passages (26a) between the outer wall and a thin shell (92). The outer diameter of the thin shell is at least about 3/16 inch (about 4 mm) less than the inner diameter of an inner wall (20) of an annular hydrodesulfurizer (10), to facilitate inserting the shift converter and heat exchanger into the hydrodesulfurizer to form a unitized assembly (2). The spiral passages open into the hydrodesulfurizer.