Hydrogen Generator Heat Exchanger Network for Stable Steam Reforming
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Solution Overview
Problem
In small to medium-sized hydrogen producing apparatuses, maintaining stable operation and high thermal efficiency is challenging due to fluctuations in steam to hydrocarbons ratio and two-phase water streams, leading to unstable system operation and catalyst deterioration.
Innovation Solution
A hydrogen generator using steam reforming with a heat exchanger network that converts water into single-phase steam through preheating with exhaust gas, maximizing thermal efficiency by reusing heat exchange media and minimizing thermal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water is supplied to the reforming apparatus without preheating, then the system structure is simple, but the water forms a two-phase stream causing unstable operation and catalyst deterioration
Solution Approach 1:
The patent applies preliminary action by preheating water in a heat exchanger before it enters the reforming apparatus. The water is heated to a temperature close to its boiling point, ensuring it enters the reformer as single-phase vapor rather than liquid water, thus preventing two-phase flow instability and catalyst deterioration while maintaining operational reliability.
Solution Approach 2:
The heat exchanger acts as an intermediary component between the exhaust gas stream and the water feed. It transfers thermal energy from the hot exhaust gas to the water, enabling temperature conditioning without direct mixing. This intermediary approach resolves the contradiction by adding a controlled heat transfer mechanism that prevents phase separation while maintaining system stability.
2Loss of energy
If additional heat exchangers are installed to improve thermal efficiency, then thermal efficiency increases, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple heat exchange functions into a single integrated heat exchanger unit. This heat exchanger simultaneously performs: (1) preheating of water using exhaust gas, (2) heating of reformate gas using waste heat, and (3) temperature control of the reforming process. By combining these functions in one device rather than using separate heat exchangers for each function, the patent achieves high thermal efficiency while minimizing the increase in device complexity.
Solution Approach 2:
The heat exchanger is designed with multi-functionality, serving as a universal thermal management component that handles multiple processes within the reforming system. It universally transfers heat between different streams (exhaust gas to water, waste heat to reformate), making it a multi-purpose device that maximizes energy recovery without requiring multiple specialized heat exchange apparatuses.
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 solution enables stable operation and high thermal efficiency by maintaining single-phase steam, improving catalyst durability and thermal efficiency, and reducing additional apparatus costs.
Implementation Method 1
water supplied to a reforming apparatus is previously heat-exchanged by exhaust gas discharged from the reforming apparatus to overheat it
Implementation Method 2
heat-exchanged by exhaust gas discharged from the reforming apparatus to overheat it
Implementation Method 3
catalytic steam reforming of hydrocarbons to produce hydrogen, carbon monoxide and carbon dioxide from steam and a gaseous hydrocarbon mixture
Implementation Method 4
steam reforming process which converts a hydrocarbon and water into hydrogen, carbon monoxide and carbon dioxide
Implementation Method 5
a water gas converter for converting carbon monoxide (CO) in reformed gas into hydrogen (H 2 ) and carbon dioxide (CO 2 )
Data Source
Figure 1
AI summary
The present invention provides a hydrogen generator for generating hydrogen through a steam-reforming process using hydrocarbons as a raw material and a method of operating the same, and, more particularly, provides a hydrogen generator for generating hydrogen through a steam reforming process, which can be stably operated because water is introduced into the hydrogen generator in the form of single phase vapor, and which can achieve high thermal efficiency using a proper heat exchanging method, and to a method of operating the same. According to the present invention, there is provided a heat exchanger network, in which heat necessary for a reforming reaction are obtained by the heat exchange of high-temperature exhaust gas or reformed gas, and in which, in a water gas converting reaction and a PSA reaction conducted at low temperatures compared to the reforming reaction, heat exchange is performed by low-temperature air or water, and the heat-exchanged air and the residual gas in the PSA reaction are used as a heat supply source for the reforming reactor together with fuel hydrocarbons, thereby minimizing the thermal loss of the hydrogen generator.