Pulse Voltage Generation for High Temperature Steam Electrolysis
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Solution Overview
Problem
High temperature steam electrolysis for hydrogen production faces challenges in maintaining efficient operation when using time-varying renewable energy sources, as it is difficult to maintain the applied voltage at the thermoneutral point and manage steam rates effectively, leading to inefficiencies and potential cell starvation or surplus states.
Innovation Solution
A hydrogen production system that includes a capacitor for storing renewable energy, a pulse voltage generation unit to create a set amplitude and cyclic period pulse voltage, and an electrolytic cell for high temperature steam electrolysis, with adjustments to the pulse voltage's cyclic period and amplitude based on measured voltage and current to maintain the thermoneutral point and optimize steam usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a time-varying renewable energy source is used as the electric power source for the electrolytic reaction, then the hydrogen production system can operate with renewable energy, but it becomes difficult to maintain the applied voltage to the electrolytic cell around the thermoneutral point
Solution Approach 1:
The patent applies periodic action by using a capacitor to store energy and release it in controlled pulses, converting the time-varying renewable energy into a stable periodic voltage output. The capacitor charges during high-voltage periods and discharges during low-voltage periods, maintaining consistent voltage to the electrolytic cell and enabling operation at the thermoneutral point despite renewable energy fluctuations.
2Adaptability or versatility
If a time-varying electric power source is used, then the system can utilize renewable energy, but the electrolytic cell may be brought into a steam starvation state or a surplus steam state due to a change in a steam rate
Solution Approach 1:
The patent implements feedback control by monitoring the voltage across the electrolytic cell and adjusting the capacitor discharge timing and duration accordingly. When voltage indicates proper operating conditions near the thermoneutral point, the system maintains current steam rate. When voltage deviates, indicating steam starvation or surplus, the system adjusts operations to restore optimal conditions, ensuring stable hydrogen production.
3Productivity
If conventional continuous voltage is applied to the electrolytic cell, then the electrolytic reaction can proceed continuously, but it is difficult to maintain efficient operation with fluctuating renewable energy inputs
Solution Approach 1:
The patent employs periodic action by using capacitor-based pulsed voltage application instead of continuous voltage. The capacitor accumulates energy during off-peak renewable energy periods and delivers concentrated energy pulses during operation, maintaining continuous hydrogen production while improving energy efficiency by operating at optimal voltage points and reducing energy losses during low-generation periods.
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 system enables highly-efficient hydrogen production by stabilizing the electrolytic reaction and optimizing steam usage, even with fluctuating renewable energy inputs, thereby improving the maintainability and efficiency of the electrolytic cell.
Implementation Method 1
a capacitor which inputs electric power energy from the renewable power supply, and stores electric power
Implementation Method 2
the steam is decomposed to hydrogen and oxygen
Implementation Method 3
an exothermic reaction by electrical resistance of the electrolytic cell itself
Data Source
AI summary
A hydrogen production system that achieves a highly-efficient hydrogen production operation even when a time-varying electric power source is used is provided. A hydrogen production system includes a capacitor inputting electric power energy from a renewable power supply, and storing electric power, a pulse voltage generation unit generating a pulse voltage having a set amplitude and a set cyclic period by using the electric power stored in the capacitor, and an electrolytic cell applying the generated pulse voltage, and generating hydrogen by high temperature steam electrolysis by using steam supplied into the electrolytic cell.