Auto-Tuning Control of PEM Water Electrolyzer

2019 ◽  
Author(s):  
Alicia Keow ◽  
Zheng Chen
Keyword(s):  
Hydrogen Production ◽  
Production Rate ◽  
Metal Hydride ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Hydrogen Production Rate ◽  
Relay Feedback ◽  
Model Free ◽  
Pem Electrolyzer ◽  
Auto Tuning

Abstract Proton exchange membrane (PEM) electrolyzers with the ability to produce gases at a pressure suitable for direct metal hydride storage are desirable because they do not require the use of compressors and other auxiliary components. Direct storage into metal hydride cylinders is made feasible when the pressure and flow rate of hydrogen is controlled. The nonlinear dynamics of the PEM electrolyzer change with temperature and pressure, both of which change with the hydrogen production rate, and are thus difficult to estimate. Therefore, a model-free, relay-feedback, auto-tuning approach is used to tune a proportional integral (PI) controller. This allows for the determination of the voltage supply to the electrolyzer by tracking the current set-point and correlating it to the hydrogen production rate. A gain scheduling approach is used to record the tuned controller’s parameters at different set-points, minimizing the frequency of tuning the device. A self-assessment test is used to determine situations where the auto-tuner should activate to update the PI parameters, thus, allowing for the system to operate without supervision. The auto-tuning PI control is successfully tested with a PEM electrolyzer setup. Experimental results showed that an auto-tuner can tune the controller parameters and produce favorable transient behaviors, allowing for a degree of adaptability for variations in system set-points.

Auto-Tuning Control of PEM Water Electrolyzer with Self-Assessment and Gain Scheduling

2020 ◽  
Author(s):  
Alicia Keow ◽  
Zheng Chen
Keyword(s):  
Metal Hydride ◽  
Transient Behavior ◽  
Gain Scheduling ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Self Assessment ◽  
Set Point ◽  
Model Free ◽  
Pem Electrolyzer ◽  
Auto Tuning

Abstract Proton exchange membrane (PEM) electrolyzer with the ability to produce gases at the pressure suitable for direct storage into metal hydride cylinders allows bypassing of compressors and other auxiliary components. For direct storage into metal hydride containers, hydrogen gas's pressure and flow rate must be well controlled. However, the PEM electrolyzer's time-variant and nonlinear dynamics call for an adaptive control to maintain its output performance. Therefore, in this paper, a model-free relay-feedback auto-tuning approach is proposed to tune a proportional-integral (PI) controller online. The controller determines the voltage supply to the electrolyzer to track a certain current set-point, which corresponds to a constant hydrogen production rate. A gain scheduling approach is developed to pick up the right controller gain at different set-points, minimizing the tuning frequency. A self-assessment algorithm is developed to determine the situations where the auto-tuner should activate to update the PI parameters, thus allowing the control system to be tuned autonomously. The auto-tuning PI control is successfully tested with a PEM electrolyzer setup. Experiment results showed that auto-tuner with gain scheduling could tune the controller parameters producing a desired transient behavior and is adaptive to the variations in set-point and operating conditions.

Modeling Solar Impacts on Hydrogen Production From Electrolysis

2008 ◽  
Author(s):  
Mark R. Campbell ◽  
Sachin S. Deshmukh ◽  
Robert F. Boehm ◽  
Rick Hurt
Keyword(s):  
Hydrogen Production ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Solar Photovoltaic ◽  
Solar Pv ◽  
Pv Array ◽  
Filling Station ◽  
Southern Nevada ◽  
Pem Electrolyzer ◽  
Exchange Membrane

A model is presented to simulate the energy production from a solar photovoltaic (PV) array in Southern Nevada and its energy produced for hydrogen production at a hydrogen filling station. A solar PV array composed of four single axis tracking units provides power to a Proton Exchange Membrane (PEM) electrolyzer, which produces hydrogen that is stored on site for use in hydrogen converted vehicles. The model provides the ability to predict possible hydrogen production at the site, as well as the amount of hydrogen required to sustain a prescribed level of vehicle usage. Together, these results made it possible to determine the energy required to produce sufficient hydrogen to sustain the vehicles, and the percentage of that energy generated by the solar PV array. For an average year in Las Vegas and a travel requirement of 57 miles/day, this percentage was found to be 33 percent. This simulation has the potential to be modified for different locations, array size, amount of storage, or usage requirement.

Low-Carbon Monoxide Hydrogen by Sorption-Enhanced Reaction

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Douglas P Harrison ◽  
Zhiyong Peng
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Hydrogen Production ◽  
Proton Exchange Membrane ◽  
Primary Energy ◽  
Proton Exchange ◽  
Raw Material ◽  
Impurity Level ◽  
Low Carbon ◽  
Enhanced Production

Hydrogen is an increasingly important chemical raw material and a probable future primary energy carrier. In many current and anticipated applications the carbon monoxide impurity level must be reduced to low-ppmv levels to avoid poisoning catalysts in downstream processes. Methanation is currently used to remove carbon monoxide in petroleum refining operations while preferential oxidation (PROX) is being developed for carbon monoxide control in fuel cells. Both approaches add an additional step to the multi-step hydrogen production process, and both inevitably result in hydrogen loss. The sorption enhanced process for hydrogen production, in which steam-methane reforming, water-gas shift, and carbon dioxide removal reactions occur simultaneously in the presence of a nickel-based reforming catalyst and a calcium-based carbon dioxide sorbent, is capable of producing high purity hydrogen containing minimal carbon monoxide in a single processing step. The process also has the potential for producing pure CO2 that is suitable for subsequent use or sequestration during the sorbent regeneration step. The current research on sorption-enhanced production of low-carbon monoxide hydrogen is an extension of previous research in this laboratory that proved the feasibility of producing 95+% hydrogen (dry basis), but without concern for the carbon monoxide concentration. This paper describes sorption-enhanced reaction conditions – temperature, feed gas composition, and volumetric feed rate – required to produce 95+% hydrogen containing low carbon monoxide concentrations suitable for direct use in, for example, a proton exchange membrane fuel cell.

scholarly journals Enhanced hydrogen production of Rhodobacter sphaeroides promoted by extracellular H+ of Halobacterium salinarum

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Jiang-Yu Ye ◽  
Yue Pan ◽  
Yong Wang ◽  
Yi-Chao Wang
Keyword(s):  
Hydrogen Production ◽  
Production Rate ◽  
Rhodobacter Sphaeroides ◽  
Coupled System ◽  
Purple Membrane ◽  
Halobacterium Salinarum ◽  
Control Group ◽  
Hydrogen Production Rate ◽  
Production Of Hydrogen ◽  
The Impact

Abstract Purpose This study utilized the principle that the bacteriorhodopsin (BR) produced by Halobacterium salinarum could increase the hydrogen production of Rhodobacter sphaeroides. H. salinarum are co-cultured with R. sphaeroides to determine the impact of purple membrane fragments (PM) on R. sphaeroides and improve its hydrogen production capacity. Methods In this study, low-salinity in 14 % NaCl domesticates H salinarum. Then, 0–160 nmol of different concentration gradient groups of bacteriorhodopsin (BR) and R. sphaeroides was co-cultivated, and the hydrogen production and pH are measured; then, R. sphaeroides and immobilized BR of different concentrations are used to produce hydrogen to detect the amount of hydrogen. Two-chamber microbial hydrogen production system with proton exchange membrane-assisted proton flow was established, and the system was operated. As additional electricity added under 0.3 V, the hydrogen production rate increased with voltages in the coupled system. Results H salinarum can still grow well after low salt in 14% NaCl domestication. When the BR concentration is 80 nmol, the highest hydrogen production reached 217 mL per hour. Both immobilized PC (packed cells) and immobilized PM (purple membrane) of H. salinarum could promote hydrogen production of R. sphaeroides to some extent. The highest production of hydrogen was obtained by the coupled system with 40 nmol BR of immobilized PC, which increased from 127 to 232 mL, and the maximum H2 production rate was 18.2 mL−1 h−1 L culture. In the 192 h experiment time, when the potential is 0.3 V, the hydrogen production amount can reach 920 mL, which is 50.3% higher than the control group. Conclusions The stability of the system greatly improved after PC was immobilized, and the time for hydrogen production of R. sphaeroides significantly extended on same condition. As additional electricity added under 0.3 V, the hydrogen production rate increased with voltages in the coupled system. These results are helpful to build a hydrogen production-coupled system by nitrogenase of R. sphaeroides and proton pump of H. salinarum. Graphical abstract

scholarly journals Nanostructured Ir-supported on Ti4O7 as a cost-effective anode for proton exchange membrane (PEM) electrolyzers

2016 ◽  
Vol 18 (6) ◽  
pp. 4487-4495 ◽  
Author(s):  
Li Wang ◽  
Philipp Lettenmeier ◽  
Ute Golla-Schindler ◽  
Pawel Gazdzicki ◽  
Natalia A. Cañas ◽  
...  
Keyword(s):  
Proton Exchange Membrane ◽  
Cost Effective ◽  
Proton Exchange ◽  
Effective Catalyst ◽  
Pem Electrolyzer ◽  
Exchange Membrane

A cost-effective catalyst Ir/Ti4O7 with superior OER activity has been developed, by which the Ir loading in the anode of a PEM electrolyzer can be reduced.

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