Hydrogen Production Step Research Articles

Understanding the electrocatalytic role of magnesium doped bismuth copper titanate (BCTO) in oxygen evolution reaction

Designing high-efficiency electrocatalysts for water oxidation has become increasingly important in the catalysis field owing to its implications for renewable energy production and storage. The production of hydrogen (H2) from water is hampered by the very sluggish kinetics of the water-splitting process. Enhancement of effective oxygen evolution reaction (OER) electrocatalysts is also required to understand the primary barrier to OER. This article investigates the electrochemical activity of magnesium-doped bismuth copper titanate (Mg-BCTO) as an efficient catalyst for the OER in water electrolysis, a critical step in hydrogen production for sustainable energy. The synthesized materials, including various stoichiometries of Mg-doped BCTO, undergo thorough physical and electrochemical characterization using XRD, FT-IR, Raman, SEM, TEM, XPS, CV, EIS, and Tafel polarization analyses. Remarkably, Mg0.1 doped BCTO demonstrates superior performance, achieving a current density of 10 mA cm−2 at a very low overpotential (η10) of 265 mV and with a Tafel slope of 92 mV dec−1. This finding not only highlights the electrocatalytic efficiency of Mg doped BCTO but also positions it as a promising model for the development of highly active and stable water oxidizing catalysts, contributing to the advancement of clean energy technologies.

Boosting butyrate and hydrogen production in acidogenic fermentation of food waste and sewage sludge mixture: a pilot scale demonstration

Within the urban scenario, the application of a biorefinery technology value chain can foster the conversion of different organic substrates into marketable and added-value products. In this work, a pilot-scale dark fermentation (DF) process has been carried out as a key step for volatile fatty acids (VFA) and hydrogen production from the liquid fraction of sewage sludge and food waste mixture. Six operating conditions have been monitored in terms of yield and process stability, by changing the hydraulic retention time (HRT) from 4 to 6 days and applying a short-term hyper-thermophilic hydrolysis (70 °C, 8 h) on the same feedstock mixture. A tubular centrifugation was utilized to remove part of the biosolids (driven to biogas production) before the DF step, which was applied on the soluble and/or colloidal organic matter only. The hydrolysis step favored the following acidification process, in which a fermentation yield up to 0.42 g CODVFA/g VS0 was achieved at 5 days as HRT. Hydrogen production (up to 34.4% v/v and 0.046 m3 H2/kg VS0) was positively affected by the hydrolysis application and by the decrease of the HRT, highlighting the possibility to produce biohythane in the modeled two-phases anaerobic bioprocess. On the other hand, without the application of the hydrolysis, a selective production of butyric acid (up to 75% COD basin) was achieved, furnishing a different valorization route for the chosen urban organic feedstock. Changes in operating conditions and performances were also reflected by the adaptation of the microbial community, whose characterization highlighted the occurrence of several fermentative microorganisms (e.g., Clostridiaceae, Ruminococcaceae).

Ruthenium Metal–Organic Frameworks as Stable Nanostructures for Selective Hydrogen Production from Acetaldehyde and Water under Mild Conditions

Hydrogen is a promising energy carrier because it is a wide and sustainable source. However, it is still extremely difficult to store and transport hydrogen safely because of its active chemical properties and harsh explosion limits. Organic liquid is a popular research field for hydrogen production and storage. Inspired by its biological metabolism, here acetaldehyde is innovatively used for hydrogen production. The hydrogen content of an acetaldehyde–water solution is 10.2 wt %, which is slightly lower than that of a methanol–water solution but much higher than that of formic acid and formaldehyde. For the first time, we prepared several ruthenium metal–organic frameworks (MOFs) as stable nanostructures for selective hydrogen production from acetaldehyde and water under mild conditions (∼60 °C). Ru-MOFs all have nanoscale pores, and the turnover frequency of ruthenium 2,3,5,6-tetramethyl-1,4-phenylenediamine for acetaldehyde decomposition is up to 223 h–1 in water at 90 °C. Because C–C bond cleavage is an inevitable step for hydrogen or energy production from C2 organics, ion chromatography, high-performance liquid chromatography, 1H NMR spectroscopy, and mass spectrometry were employed to propose a catalytic process of hydrogen production from acetaldehyde decomposition. We evidently prove that water participates in acetaldehyde decomposition, thereby claiming an acetaldehyde–water reforming process. Additionally, we confirm that formic acid and acetic acid are the intermediates during the hydrogen production process. This research not only holds great promise for hydrogen production from C2 organics at low temperatures, as well as catalytic technology for C–C bond cleavage, but it also provides certain profound scientific insights for hydrogen or energy production from multicarbon organics, such as biomass.

Preparation and characterization of nanostructured Fe-doped CoTe2 electrocatalysts for the oxygen evolution reaction.

The key step for hydrogen production through water electrolysis is the development of highly efficient and inexpensive oxygen evolution reaction (OER) catalysts. In this work, we report the successful synthesis of a nanostructured Fe-doped cobalt-based telluride (Fe-doped CoTe2) catalyst on Co foam by a simple one-step hydrothermal synthesis method, which shows excellent OER performance. The influences of Fe doping amounts and reaction temperatures on the morphology, structure, composition, and the OER performance of cobalt-based tellurides have been systematically studied. The optimal sample Co@0.3 g FeCoTe2-200 exhibits a low overpotential of 300 mV at a current density of 10 mA cm-2, and a small Tafel slope of 36.99 mV dec-1, outperforming the undoped cobalt telluride catalysts (Co@CoTe2-200). The Co@0.3 g FeCoTe2-200 electrode also reveals a small overpotential degradation of around 26 mV after an 18-hour continuous OER process. These results unambiguously confirm that Fe doping helps improve the OER activity and long-term catalytic stability. The superior performance of nanostructured Fe-doped CoTe2 can be attributed to the porous structure and the synergistic effect of Co and Fe elements. This study provides a new approach for the preparation of bimetallic telluride catalysts with enhanced OER performance, and Fe-doped CoTe2 holds substantial promise for use as a high-efficiency, cost-effective catalyst for alkaline water electrolysis.

Double surface modification of graphite felt using a single facile step for electrolytic hydrogen production assisted by urea

Graphite felt (GF) is modified electrochemically using a facile controllable method via scanning the potential from +2 to ‒1.5 V in solutions containing various NiCl2 concentrations. By increasing the NiCl2 amount, the anodic oxidation and cathodic deposition processes are enhanced, and the GF surface is simultaneously functionalized. Firstly, at a high positive potential, GF’ functionalization occurs by making a defect in the carbon framework. Then, at a high negative potential, the rate of hydrogen evolution increases and produces a strong homogeneously uniform Ni(OH)2 coating at the GF surface. Modified GF is examined by SEM, mapping EDX, HR-TEM, XPS, XRD, Raman, and contact angle measurements. Interestingly, the Ni(OH)2 film deposited at GF from 100 mM NiCl2 solution (Ni(OH)2/GF-100) enhances the hydrogen evolution reaction in alkaline medium by deriving a current density of 10 mA cm−2 at a low overpotential of 69 mV which approaches the value of the benchmark catalyst. Additionally, the Ni(OH)2/GF-100 electrode supports urea oxidation as it drives a current density of 10 mA cm−2 at a potential of 1.38 V vs RHE. Therefore, Ni(OH)2/GF-100 is used as a bifunctional catalyst to replace the unfavourable anodic reaction (oxygen evolution reaction) with urea oxidation. Furthermore, a two electrode cell for urea electrolysis displays a cell voltage of 1.47 V, which is lower than that of water splitting by about 270 mV, to drive a current density of 10 mA cm−2 and shows superb stability over a prolonged electrolysis time of 24 h. So, this approach introduces an energy-saving route.

Ammonia Decomposition over Ru/SiO2 Catalysts

Ammonia decomposition is a key step in hydrogen production and is considered a promising practical intercontinental hydrogen carrier. In this study, 1 wt.% Ru/SiO2 catalysts were prepared via wet impregnation and subjected to calcination in air at different temperatures to control the particle size of Ru. Furthermore, silica supports with different surface areas were prepared after calcination at different temperatures and utilized to support a change in the Ru particle size distribution of Ru/SiO2. N2 physisorption and transmission electron microscopy were used to probe the textural properties and Ru particle size distribution of the catalysts, respectively. These results show that the Ru/SiO2 catalyst with a high-surface area achieved the highest ammonia conversion among catalysts at 400 °C. Notably, this is closely related to the Ru particle sizes ranging between 5 and 6 nm, which supports the notion that ammonia decomposition is a structure-sensitive reaction.

Impacts of ruthenium valence state on the electrocatalytic activity of ruthenium ion-complexed graphitic carbon nitride/reduced graphene oxide nanosheets towards hydrogen evolution reaction

Design and engineering of effective electrode catalysts represents a critical first step for hydrogen production by electrochemical water splitting. Nanocomposites based on ruthenium atomically dispersed within a carbon scaffold have emerged as viable candidates. In the present study, ruthenium metal centers are atomically embedded within graphitic carbon nitride/reduced graphene oxide nanosheets by thermal refluxing. Subsequent chemical reduction/oxidation leads to ready manipulation of the ruthenium valence state, as evidenced in microscopic and spectroscopic measurements, and hence enhancement/diminishment of the electrocatalytic activity towards hydrogen evolution reaction in both acidic and alkaline media. This is largely ascribed to the increased/reduced contribution of the Ru valence electrons to the density of state near the Fermi level which dictates the binding and reduction of hydrogen. Results from this study highlight the significance of the valence state of metal centers in the manipulation and optimization of the catalytic performance of single atom catalysts.

Experimental and Theoretical Studies on Water-Added Thermal Processing of Model Biosyngas for Improving Hydrogen Production and Restraining Soot Formation

The upgrading of biosyngas to convert methane into syngas is a necessary step for hydrogen production from biomass. However, this process is highly energy-demanding. In this study, a model biosyngas containing H2, CH4, CO, and CO2 were thermally treated between 1200 and 1500 °C. The gas mixture, comprised of H2 (33 vol %), CH4 (12 vol %), CO (28 vol %), CO2 (25 vol %), and He (2 vol %), was diluted with argon and the effect of reaction temperature (1200–1500 °C), water addition (0–44.3 mol %), and residence time (23, 46, and 76 μs in corresponding to flow rates of 1500, 2500, and 5000 mL/min at normal temperature and pressure, respectively) were studied. A possible reaction scheme for the upgrading of the model gas is proposed based on the kinetic simulation with CHEMKIN. The main reaction pathways involve dry reforming of methane and reverse water-gas shift (WGS) reactions. The kinetic simulation explained the finding that CO production was negatively influenced by the water content via the WGS reaction. The main side reaction is the methane pyrolysis reaction which causes the formation of carbon. The carbon formed in the reforming was characterized by SEM and Raman spectroscopy. SiO2 needle-like microdomains are observed at the top of the reactor heating zone, while the central part of the heating zone was covered by carbon with a disordered, amorphous, low-density soot structure. It is proposed that the SiO2 species formed by the chemical reaction between the reactor wall material and the reactants act as a support to anchor the carbon formed.

Continuous Room-Temperature Hydrogen Release from Liquid Organic Carriers in a Photocatalytic Packed-Bed Flow Reactor.

Despite the potential of hydrogen (H2) storage in liquid organic carriers to achieve carbon neutrality, the energy required for H2 release and the cost of catalyst recycling have hindered its large‐scale adoption. In response, a photo flow reactor packed with rhodium (Rh)/titania (TiO2) photocatalyst was reported for the continuous and selective acceptorless dehydrogenation of 1,2,3,4‐tetrahydroquinoline to H2 gas and quinoline under visible light irradiation at room temperature. The tradeoff between the reactor pressure drop and its photocatalytic surface area was resolved by selective in‐situ photodeposition of Rh in the photo flow reactor post‐packing on the outer surface of the TiO2 microparticles available to photon flux, thereby reducing the optimal Rh loading by 10 times compared to a batch reactor, while facilitating catalyst reuse and regeneration. An example of using quinoline as a hydrogen acceptor to lower the energy of the hydrogen production step was demonstrated via the water‐gas shift reaction.

Exergy and energy analysis of hydrogen production by the degradation of sodium borohydride in the presence of novel Ru based catalyst

Chemically possible hydrogen storage material of the most important and widely used metal hydride compound is sodium borohydride. A current research issue is the development of systems that allow regulated hydrogen generation employing appropriate catalysts for the creation of hydrogen gas from the hydrolysis of sodium borohydride (NaBH4). In this study, controlled hydrogen production from alkali solution of NaBH4 was aimed. On hydrogen generation rate (HGR), the effects of NaBH4 and alkaline solution concentrations, catalyst quantity, and temperature were examined. Considering the energy and exergy analysis, which have gained importance in the international arena in recent years, in this study, the exergy energy analysis of the environment in which the sodium borohydride solution is located was performed. The best one of the Ru-based catalysts synthesized in different atomic ratios was determined as 90:10 RuCr. The surface characterization of the obtained catalyst was carried out using scanning electron microscope (SEM-EDX) and X-ray diffractometer (XRD). In the kinetic calculations, the activation energy was calculated as 35,024 kj/mol and the reaction ordered n was found to be 0,65. By applying exergy and energy analysis to the hydrogen production step, the energy and exergy efficiency of the system were found to be 24% and 7%, respectively.

Performance analysis of hydrogen iodide decomposition membrane reactor under different sweep modes

Hydrogen iodide decomposition is the core hydrogen production step in the sulfur-iodine thermochemical cycle, which determines the hydrogen production rate and thermal efficiency of the device. The conventional decomposition reactor is limited by equilibrium conditions, so the hydrogen iodide conversion rate is low at normal reaction temperature, and membrane reactor technology can break the limit of equilibrium condition and greatly improve the conversion rate. Most of the previous hydrogen iodide membrane reactor models were built under isothermal conditions and did not consider the influence of different sweep modes. In this paper, a one-dimensional non-isothermal hydrogen iodide decomposition membrane reactor mathematical model in co-current and countercurrent sweep modes is established, and the effects of reactor parameter on hydrogen iodide conversion and hydrogen recovery rate are analyzed under the two sweep modes. The results show that the countercurrent mode can obtain higher hydrogen iodide conversion rate than the co-current mode under larger sweep flow rate, inlet pressure of reaction and permeation zone, reactor length; the maximum recovery rate of hydrogen in countercurrent mode is close to 100%. A modified membrane reactor structure combining the traditional reactor and membrane reactor is proposed, which could effectively increase the hydrogen permeation flux per unit membrane surface. In engineering application, the reasonable design of the modified membrane reactor can effectively reduce the investment cost of the membrane reactor on the premise of satisfying the hydrogen production rate.

Supercritical water partial oxidation mechanism of ethanol

In recent years, supercritical water as a green reaction medium to convert organic matter to produce hydrogen has attracted significant attention. At present, the mechanism of the supercritical water partial oxidation (SCWPO) process is still unknown when complete gasification is achieved. In this paper, a detailed mechanism for SCWPO of ethanol was proposed by establishing a novel kinetic model with a wide reaction temperature range. This model described the formation and consumption of gas products (H2, CO, CH4, and CO2) from ethanol by partial oxidation in the supercritical water environment through nine reactions. The results showed that the dehydrogenation and pyrolysis of ethanol were the main ways to generate H2 in the early stage, and the water-gas shift reaction had the most significant impact on hydrogen production in the later stage. The hydrogenation reaction of the intermediate product ethane was a key step for complete conversion into combustible gas products. The steam reforming reaction of a large amount of CH4 produced by ethanol and intermediate product will become the rate-determining step for hydrogen production.

Development of bamboo charcoal and fragaria vesca powder photocatalysts in hydrogen production via water splitting

Hydrogen has become the subject of attention as an environmentally friendly and effective source in recent years. The photocatalysis method with biomass-photocatalyst is an alternative step for hydrogen production via water splitting. In this study, bamboo charcoal (BC) and Fragaria Vesca Powder (FVP) are biomass materials used to develop photocatalysts in hydrogen production. The light source for photocatalysis was a halogen lamp with a wavelength of 560 nm. The hydrogen gas produced is measured using the MQ-8 sensor which is capable of measuring hydrogen gas in 100–10,000 ppm. Hydrogen production is significantly increased with the combination of the BC and FVP photocatalysts. Based on scanning electron microscope (SEM) image analysis by Image J software, BC and FVP have a negative and positive charge, respectively. The aromatic carbon ring in BC has an energy gap of 2.48 eV whereas that in FVP has a lower energy gap, 2.32 eV due to functional groups energizing electron in the FVP aromatic ring. The interaction between positive and negative charges when BC and FVP are combined generates the second lower energy gap in the combined catalyst, 1.66 eV that tends to increase electron density on the catalyst surface. The more dense electrons destabilize more hydrogen and covalent bonds in water increasing hydrogen production by 20 times from that with BC only or by 4 times from that with FVP only. When aluminum foil (AF) was added to the bottom of the reactor tube, the photocatalyst's performance was strengthened. The AF material was an 8011 aluminum alloy with a thickness of 0.02 mm and a diameter of 80 mm. AF has two important roles, that is, accelerates reduction reaction and facilitates the breaking of the hydrogen and covalent bonds in water

Low-emission pre-combustion gas-to-wire via ionic-liquid [Bmim][NTf2] absorption with high-pressure stripping

Autothermal reforming is an important pathway to hydrogen via fossil fuel decarbonization. Traditionally, the finishing step of hydrogen production via autothermal reforming consists of decarbonation via conventional aqueous-amine absorption which incurs a huge energy penalty due to high heat-ratio and low-pressure carbon dioxide stripping entailing costly compression for geological storage. This work proposes and assesses an alternative high-pressure temperature-swing hydrogen decarbonation that promotes stripping at high-pressure reducing carbon dioxide compression costs. Such new hydrogen decarbonation uses 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide ionic-liquid physical-absorption due to its solute affinity, low vapor-pressure, high thermal stability and low heat consumption for carbon dioxide stripping at high-temperature and high-pressure. Technical and economic aspects of the ionic-liquid temperature-swing decarbonation are evaluated and compared with the conventional aqueous-amine decarbonation. Results showed that high-pressure ionic-liquid stripping requires 5.5 times less heat to produce a high-pressure carbon dioxide stream and reduces 4.3 times its compression power. These results directly impact net power exportation of the combined-cycle hydrogen-fired power plant; i.e., the ionic-liquid gas-to-wire exports 35.6% more electricity than the aqueous-amine counterpart. Economically, the ionic-liquid gas-to-wire has 36% higher revenues, entailing a net value 2.5 times higher (US$ 390.2*106) and 5 years lower payback-time than the conventional aqueous-amine counterpart.

Exergy analysis for the Na-O-H (sodium-oxygen-hydrogen) thermochemical water splitting cycle

Thermochemical water splitting cycles are considered an attractive option to produce H2, a substance with many important applications for society such as ammonia production because they do not require fossil fuels. In contrast, they obtain H2 decomposing water by means of cyclic chemical reactions. There are a wide variety of thermochemical ones under research, including the relatively new Na–O–H (sodium–oxygen–hydrogen) cycle proposed in 2012 by a research group. Despite introducing a new potential thermochemical cycle, those previous researchers do not investigate the thermal performance of it. Such task can be done through an exergy analysis. So, the aim of the paper is to evaluate the exergy performance of the Na–O–H cycle and its chemical reactions. This goal is accomplished by implementing in EES (Engineering Equation Solver) software exergy efficiency (ε1) and exergy destroyed (ED_1) balances for the cycle and their reactions considering specific conditions of pressure (p) and temperature (T). This approach allows understanding how these two variables influence the system performance, which could compromise its actual implementation and economic feasibility if it has low thermal efficiency. According to the results: reaction 1 (hydrogen production step) has mean ε1=96% and ED_1 = 8.5 kJ under 100–300 °C at 0–1 bar; reaction 2 (metal separation step) has ED_2 = 280 kJ and ε2=56% at 450 °C considering vacuum condition; hydrolysis step (reaction 3) has average ε3=87% and ED_3 = 18 kJ at 25–200 °C under 0–1 bar. Then, the Na–O–H cycle has overall ε=82% and ED = 306 kJ to produce 1 mol of H2. These values of ε and ED are theoretical and maximized ones. In practical situations, such amounts probably will reduce in function of unavoidable irreversibility present in actual systems such as pressure drop and heat loss that were neglected in the work to facilitate its development. Finally, it concludes the Na–O–H cycle has relatively high exergy efficiency, making it a potential hydrogen production method. However, its practical implementation in the future must overcome some of its drawbacks, by means of more research, like the low thermal efficiency of reaction 2 when compared to reactions 1 and 3 beyond the low pressure needed to perform such step.

Hidrojen Üretimi için Üç Adımlı Cu-Cl Termokimyasal Sistemin Enerji ve Ekserji Analizi

Thermochemical cycle systems produce hydrogen without the release of greenhouse gases using heat and electrical energy from renewable energy sources. In this study, the energy and exergy analyses of designed high-temperature Cu-Cl thermochemical conversion system are performed. Parametric studies are carried out by examining the analyses according to different reference temperature values and reaction temperatures. The exergy rates and exergy destruction rates for each step of cycle, and also the exergy efficiency of system are investigated. The energy and exergy efficiencies of Cu-Cl thermochemical cycle at a reference ambient temperature of 25 °C are found as 55.41% and 66.09%, respectively. In addition, the maximum exergy destruction in the investigated system occurred in the hydrogen production step.

Synthesis of Ni12P5 on Co3S4 material for effectively improved photocatalytic hydrogen production from water splitting under visible light

Building a good catalyst with high efficiency and low cost is a key step in photocatalytic hydrogen production. In this study, catalyst Ni12P5 is successfully modified on Co3S4 by two step hydrothermal methods. The catalyst Ni12P5 has a good promoting effect on the photocatalytic hydrogen production of Co3S4. Composite samples 8% Ni12P5/Co3S4 had the highest photocatalytic hydrogen production activity, and the hydrogen yield reach 4922.4 μmol g−1 h−1, which is 4.8 times higher than that of the original Co3S4 under visible light. The composite sample Ni12P5/Co3S4 maintains good stability of photocatalytic hydrogen production in three cycles. Ni12P5/Co3S4 samples are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Ultraviolet–visible diffuse reflectance spectra (UV–Vis DRS), X-ray photoelectron spectroscopy (XPS), electrochemistry and fluorescence (PL), and their physical and chemical properties was analyzed. Electrochemical measurements show that the enhancement of photocatalytic activity is attributed to the high separation and migration of photoinduced electrons and holes, which is consistent with the photocatalytic hydrogen production activity. The results provide a novel idea for the synthesis of other non-noble metal composite photocatalyst, and have important inspiration significance.

Gibbs free energy [formula omitted] analysis for the Na[sbnd]O[sbnd]H (sodium-oxygen-hydrogen) thermochemical water splitting cycle

The main aim of the paper is to determine a theoretical range of operational conditions for the three chemical reactions of the NaOH (sodium-oxygen-hydrogen) thermochemical water splitting cycle by performing a Gibbs free energy (ΔG) analysis. ΔG is a thermodynamic parameter that allows determining if a chemical reaction is able to occur due to its enthalpy (ΔH) and entropy (ΔS) changes under specific conditions of pressure (p) and temperature (T). The methodology consists of implementing in Engineering Equation Solver (EES) software equations related to ΔH and ΔS for the three chemical reactions of the NaOH process, considering specific conditions of p and T with proper thermodynamic data to calculate ΔG. The main obtained results are: reaction 1, hydrogen production step, has ΔG < 0 for any values of T and p considered in the study; it can be performed at 100 °C under 1 bar; reaction 2, metal separation step, only can proceed under vacuum atmosphere at around 500 °C; reaction 3, hydrolysis step, always has negative Gibbs free energy despite pressure and temperature values and it can be carried out under 1 bar at 25 °C. Moreover, the methodology described in this paper could be used to investigate operational conditions for thermochemical processes.

Application of corrosion-resistant Corning advanced-flow reactors for multiphase Bunsen reaction - Part two: investigation on multiphase reaction

Bunsen reaction ( 2 H 2 O + I 2 + S O 2 → H 2 S O 4 + 2 H I ) is a key step for hydrogen production from either the H2S splitting cycle or the sulfur-iodine (S-I) cycle of water splitting. As pointed out in part one, when engineering this reaction, many challenges such as side reactions and corrosion impede scaling up this process. Using iodine-toluene solution to provide flowing iodine below the melting point of iodine renders the Bunsen reaction to be conducted at ambient temperature such that these challenges can be either overcome or eased. However, using toluene as the iodine solvent makes the Bunsen reaction a multiphase reaction system which includes gas, aqueous, and organic phases. Glass-made Corning® advanced-flowTM reactors (AFRs) can be used for Bunsen reaction because they are good at resisting corrosion, improving mixing efficiency of multiphase fluids, and allowing seamless scaling up. Part one has studied the absorption behavior of SO2 gas in the liquids used for Bunsen reaction (water, toluene and water-toluene mixture). Part two (this work) mainly studies the Bunsen reaction using the Corning® microscale (LF) and milliscale (G1) AFRs. When I2 was dissolved in toluene, the Bunsen reaction was conducted by feeding SO2 gas, water, and I2/toluene solution into the AFRs. SO2 and I2 were used as the limiting reactants in turn, and the effects of operating conditions such as gas and liquid flow rates, water to toluene ratio, and temperature in the range (22-80 oC) on the absorption rates of SO2 and the I2 reaction rate were studied. The results confirm the seamless scaling-up capability of the Corning reactors when the flow rates were increased twenty times from AFR-LF to AFR-G1.

Thermodynamic viability of a new three step high temperature Cu-Cl cycle for hydrogen production

A new three step high temperature Cu-Cl thermochemical cycle for hydrogen production is presented. The performance of the proposed cycle is investigated through energy and exergy approaches. Furthermore, the effects of various parameters, such as the temperatures of the steps of the cycle and power plant efficiency, on various energy and exergy efficiencies are assessed with parametric studies. The results show that the exergy and energy efficiencies of the proposed cycle are 68.3% and 32.0%, respectively. In addition, the exergy analysis results reveal that the hydrogen production step has the maximum specific exergy destruction with a value of 150.9 kJ/mol. The results suggest that proposed cycle may provide enhanced options for high temperature thermochemical cycles by improving thermal management without causing a sudden temperature jump/fall between the hydrogen production step and other steps.