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Hydrogen is a carbon-free fuel and can be expected to play a significant role in the global clean energy transition. In this study, two proposed small-scale hydrogen production plant configurations were designed and simulated for high-purity hydrogen production at a rate of 25 kg H2 /day. The feasibility and economic viability of the proposed plant configurations were examined. Additionally, the performance and sensitivity analysis were assessed under different operating conditions. Configuration A proposed to use two reactors for ammonia cracking and H 2 separation, respectively. Configuration B considers that the decomposition of ammonia and H 2 separation simultaneously occurs in a single integrated reactor. Despite the configuration B was more energy efficient than configuration A but both configurations are applicable. The total H 2 production cost of configuration A was 6.39 $/kg H2 and that of configuration B was 6.06 $/kg H2. Since the proposed plant configurations generated both hydrogen and nitrogen, the total cost of production was distributed between them. Therefore, the final H 2 and N 2 separation costs of configuration A was 5.05 $/kg H2 and 1.14 $/kg N2 , and configuration B was 4.72 $/kg H2 and 1.08 $/kg N2. The hydrogen production cost from different ammonia synthesis pathways was compared. The technology readiness level (TRL) for hydrogen production from ammonia cracking was assessed and identified at a range of TRL 4–6. It can also be considered that the ammonia synthesis pathway controlled the ammonia prices and subsequently the hydrogen production cost. • Two proposed configurations were designed for H 2 production from blue NH 3. • Techno-economic assessment was performed for small-scale H 2 plants. • The final H 2 cost of proposed configuration A was higher than configuration B. • The H 2 production cost from different NH 3 synthesis pathways was also compared. • The pathway of NH 3 synthesis influenced the prices of NH 3 and H 2. [ABSTRACT FROM AUTHOR]

The interest in nonthermal discharge plasma has recently increased over the last few decades due to the ability to generate new radicals at atmospheric pressure. This paper presents a comprehensive analysis of the dissociation processes and reaction rates of various water vapour samples by dielectric barrier discharge plasma (DBD). The influence of water contamination and the presence of ammonia (NH 3) on hydrogen production from water vapour was investigated. A novel reaction rate expression was proposed to fit the plasma-water vapour experiment results. The hydrogen production and conversion rate of pure reverse osmosis (RO) water samples showed greater results than the contaminated water samples in all experiments at different tested bubbling temperatures. The higher conversion rate was obtained from RO water combined with 1%NH 3 at a bubbling temperature of 50 °C and was 1.17%. The water contamination influenced the generated DBD plasma micro discharges, consequently decreasing the electron collisions, leading to lower water vapour conversion into constituent elements H 2 and O 2. It was also found that the influence of ammonia on the water vapour decomposition was related to the NH 3 concentration. Moreover, the reaction rate showed good agreement with the experimental results. It was observed that the energy efficiencies were obtained at an operating temperature of 50 °C for pure RO, GTW, and CTW water samples enhanced by adding 1%NH 3 , for example, the RO energy efficiency value at a bubbling temperature of 50 °C increased from 0.133% to 1.15% because of more hydrogen was generated. It implies that the water vapour decomposition processes are influenced by the following parameters: input gas temperature, reaction time, plasma power, oven or reactor heating temperature, the separation method, sampling method, and sampling collection time. [Display omitted] • The hydrogen production from various water types by DBD plasma is investigated. • The presence of ammonia enhanced the hydrogen production of water vapour. • The water contamination has a negative effect on the plasma water decomposition. • The new rate equation showed a good agreement with experimental results. [ABSTRACT FROM AUTHOR]

Catalytic ammonia (NH 3) decomposition has been identified as a COx-free, sustainable hydrogen production method for fuel cell applications. In this study, the performance of plasma–catalyst-based NH 3 decomposition over ruthenium (Ru/Al 2 O 3) and soda glass (SiO 2) catalytic materials at atmospheric pressure and ambient temperature was investigated. NH 3 decomposition reactions were conducted in a dielectric barrier discharge plasma plate-type reactor. NH 3 was fed into the plate catalytic microreactor at flow rates of 0.1–1 L/min and plasma voltages of 12–18 kV. Compared to plasma NH 3 decomposition without a catalyst, plasma–catalyst-based NH 3 decomposition showed a significant enhancement of the hydrogen production rate and energy efficiency. Furthermore, the hydrogen concentration results obtained over the Ru/Al 2 O 3 catalyst were higher than those over the SiO 2 catalyst because Ru/Al 2 O 3 possesses good electronic properties and exhibits high sensitivity to NH 3 decomposition. In addition, the resulting plasma heat enhanced the activation of the catalytic material, subsequently leading to an increase in the hydrogen production rate from NH 3. The maximum conversion rates were 85.65% and 84.39% for Ru/Al 2 O 3 and SiO 2 , respectively. Moreover, the energy efficiency of NH 3 decomposition over the Ru-based catalyst material was higher than that over the SiO 2 material. The presence of the catalyst active sites and plasma enhanced the mean electron energy, which could enhance the dissociation of NH 3. It can be concluded that the SiO 2 material can be utilised as a catalyst and that its combination with plasma accelerates the decomposition process of NH 3 and incurs a lower cost compared to Ru materials. [Display omitted] • The hydrogen concentration result of the Ru/Al 2 O 3 catalyst was higher than that obtained from the SiO 2. • The maximum conversion rate was 85.65, 84.39% using Ru/Al 2 O 3 , and SiO 2 , respectively. • The resulting plasma heat raised the activation of the catalytic material. • The energy efficiency of the NH 3 decomposition using Ru-catalyst material was greater than that obtained from SiO 2. • The SiO 2 has the ability to activate the decomposition process of ammonia at low cost compared with Ru materials. [ABSTRACT FROM AUTHOR]

Energy and exergy analyses were performed on a glass furnace regenerator and hydrogen production via thermal catalytic ammonia decomposition. A novel integration between energy and exergy analyses was suggested to predict the performance of thermodynamic and hydrogen production systems. It was found that the heat recovered by the combustion air of the south side regenerator was higher than that on the north side because of the fouling effect of the deposit materials and the heat lost through the regenerator walls. The maximum energy and exergy efficiencies of the south side regenerator were 98% and 93%, respectively, while those of the north regenerator side were 96.3% and 80%, respectively. The integration between energy and exergy analyses was also applied to investigate the performance of H 2 production from the catalytic NH 3 decomposition system. The conversion rate results proved that an increase in the ammonia feeding pressure was unfavorable. Moreover, the maximum energy and exergy efficiencies of the NH 3 thermal decomposition system were 73.5% and 13.34% at a feeding pressure of 100 kPa, respectively. Furthermore, the non-equilibrium of the system is identified from the integrated effectiveness and entropy generation number. [ABSTRACT FROM AUTHOR]

The diffusion of hydrogen through palladium and palladium-copper alloys membrane have been provided the highest hydrogen selectivity and permeance. In this study the composite Pd 0.60 -Cu 0.40 wt% membrane foil with thickness 20 μm was measured in the micro-channel plate reactor (MPR) with gap length 4.5 mm. The hydrogen permeation flux was measured at atmospheric feeding pressure for 100% H 2 concentration in the temperatures range of 423–573 K under heating only and plasma-heating experiments. The plasma firing high voltage source ranges of 10–18 kV are tested. The hydrogen permeation flux and hydrogen permeability have been calculated according to Fick's and Sieverts combining laws with power exponent n-value 0.5. It was found that the maximum hydrogen flux, hydrogen permeability and Permeation rate percent of the heating only experiment at MPR heating temperature of 573 K and flow rate 0.1 l/min. In the plasma heating experiment, it was observed that the maximum hydrogen flux, hydrogen permeability, and permeation rate percent at MPR heating temperature of 573 K and plasma firing voltage of 14 kV. Also, the hydrogen permeation rate percent decreased due to the hydrogen reverse reaction even though the plasma firing voltage increased to 16 kV and 18 kV. The results also reveal that the activation energy and Pre-exponential constant factor decreased with increasing the feeding H 2 flow rate while the linear regression R 2 decreased with increasing H 2 feeding flow rate that in the heating only experiment, in contrast, the plasma-heating experiment showed non-linearity values. A comparison between both experiments showed the hydrogen permeation flux of the plasma-heating experiment is higher than that obtained from the heating only experiment, additionally; the plasma effect increased at low hydrogen flow rates. In contrast, the energy efficiency of heating only experiment was higher than that obtained from the plasma-heating experiment due to the total energy consumption of plasma experiment is high. • The maximum H 2 flux, permeability and Permeation rate percent of the heating only experiment at temperature of 573 K. • In plasma experiment, the maximum H 2 permeation results were at temperature of 573 K and plasma voltage of 14 kV. • The H 2 permeation is decreased due to the hydrogen reverse reaction in plasma-heating experiment. • The H 2 permeation flux of the plasma-heating experiment is higher than that obtained from the heating only experiment. [ABSTRACT FROM AUTHOR]

• The H 2 flux of GDP experiment versus the inverse temperature showed a continuous increase with the PMCR heating temperature. • The maximum energy efficiency was 63.37% and 48.7% for GDP and PDP experiments respectively. • A comparison between the yield ratios of both experiments has been developed. • It was concluded that the influence of plasma on hydrogen permeation was higher than heating effect. This study analyses the performance of hydrogen permeation through thin palladium 60%-copper40% alloy membrane with a thickness of 15 μm in 1 mm gap length plate micro channel reactor (PMCR) under gas driven permeation (GDP) and plasma driven permeation (PDP). Pure hydrogen gas was fed into the PMCR at atmospheric pressure and temperature range of 423–573 K. The hydrogen permeation flux plot of GDP experiment versus the inverse temperature showed a continuous increase with the PMCR heating temperature, while in PDP experiment the trend behavior showed a small peak increase at plasma applied voltage 16 kV and temperature 573 K. The energy efficiency of both experiments were determined, it was found that the energy efficiency values of GDP experiment was higher than that obtained from PDP experiment due to the total heat added to the plasma system. Further, the maximum energy efficiency of GDP experiment was 63.37% at H 2 flow rate 0.1 L/min and temperature 573 K, while in PDP experiment the maximum value was 48.7% at plasma voltage 14 kV, H 2 flow rate 0.1 L/min and temperature 573 K. Further, the yield ratio evaluation versus the total energy consumptions was determined, the stronger effect on yield ratio was noted when the energy added to the system increased. A comparison between the yield ratios of both experiments has been developed, it was concluded that the influence of plasma on hydrogen permeation was higher than heating effect, additionally the plasma effect increased at low temperatures. The hydrogen output energy versus the energy consumption was compared, it was observed in GDP results that the output H 2 energy very low at low temperature and increased to the maximum value 20.89 W at 573 K. While in PDP results, it was seen a continuous increase with discharge voltage to reach the maximum value 20.997 W at 14 kV and temperature of 573 K. [ABSTRACT FROM AUTHOR]