A novel fuzzy logic based safe operation oriented control technique for driving HHO dry cell systems based on PWM duty cycle

The presented study provides details on Fuzzy Logic based control of HHO generators aims at protecting the HHO generator from extreme temperature effects while maximizing the hydrogen production. The Fuzzy Logic Controller mainly focuses on protecting the generator from the harsh effects of process related over heating problems while maximizing the hydrogen production. The designed controller takes two process specific parameters, such as temperature and the HHO flow rate, and optimizes the operation of the reactor for maximization of production. In order to prove the effectiveness of the developed Fuzzy Logic based control approach, a comparative study on performance of conventional and presented novel Fuzzy Logic based systems are presented. The advantage of the Fuzzy Logic Controller is that it protests the reactor and allows continuous production of HHO gas while the conventional approach leads to damage to the reactor or interrupted operation due to overheating.     

A mini-review of ferrites-based photocatalyst on application of hydrogen production

Photocatalytic water splitting for hydrogen production is a promising strategy to produce renewable energy and decrease production cost. Spinel-ferrites are potential photocatalysts in photocatalytic reaction system due to their room temperature magnetization, the high thermal and chemical stability, narrow bandgap with broader visible light absorption, and proper conduction band energy level with strong oxidation activity for water or organic compounds. However, the fast recombination of the photoexcited electrons and holes is a critical drawback of ferrites. Therefore, the features of crystallinity, particle size, specific surface area, morphology, and band energy structure have been summarized and investigated to solve this issue. Moreover, composites construction with ferrites and the popular support of TiO₂ or g-C₃N₄ are also summarized to illustrate the advanced improvement in photocatalytic hydrogen production. It has been shown that ferrites could induce the formation of metal ions impurity energy levels in TiO₂, and the strong oxidation activity of ferrites could accelerate the oxidation reaction kinetics in both TiO₂/ferrites and g-C₃N₄/ferrites systems. Furthermore, two representative reports of CaFe₂O₄/MgFe₂O₄ composite and ZnFe₂O₄/CdS composite are used to show the efficient heterojunction in a ferrite/ferrite composite and the ability of resistance to photo-corrosion, respectively.     

Optimisation of dry cell electrolyser and hydroxy gas production to utilise in a diesel engine operated with blends of orange peel oil in dual-fuel mode

This study aims at producing hydroxy (HHO) gas using a dry cell electrolysis setup and utilising it along with orange oil in a diesel engine. First an electrolyser was designed considering the optimised values of the material (SS316L), electrolyte (NaOH), and electrode gap (2 mm). Then the biodiesel obtained from the waste orange peels, after transesterification, were blended with diesel at 25 and 50% by vol. The HHO gas was produced by the water electrolysis method by a plate-type electrolyser having a maximum production rate of 2.5 LPM with NaOH as the electrolyte. HHO gas was inducted through the inlet manifold along with the fresh air at a constant rate of 2 LPM with both the biodiesel blends. The performance, emission, and combustion outcomes of the single cylinder diesel engine for different load conditions (0–100%) were tested for all the blends with and without HHO addition. The results showed a considerable increase in brake thermal efficiency of 1.54% at full load condition, with a noticeable decrease in fuel consumption by 11.1% compared to conventional diesel fuel, was achieved for the O25 blend with HHO induction. Moreover, emissions like hydrocarbon, carbon monoxide and smoke were reduced by 17.6, 29.5, and 12.1%, respectively. However, the improvement in combustion outcomes led to the increase in nitrogen oxides emission by 9.67%. This study helped to understand the production process of HHO gas by dry cell electrolyser and its effect on the blend of orange oil methyl ester and diesel in dual-fuel mode.     

A review on bio‐hydrogen production technology

The progress of bio‐hydrogen technology has led to the development of new energy technologies and is significant for the sustainable use of energy. After summarizing current research results, this study discusses that the key to increasing the hydrogen production rate is to improve the activity of hydrogen producing bacteria under the conditions of anaerobic fermentation. Using waste to prepare hydrogen producing bacteria is the developmental trend. The primary factors influencing bio‐hydrogen production from plant straw fermentation are also pointed out, indicating the method to improve the hydrogen production rate from plant straw. In addition, application of artificial intelligence technology to a bio‐hydrogen production reactor is helpful to achieve automatic control of continuous bio‐hydrogen production and improve the rate of hydrogen production.     

pH值调控对发酵产氢的影响

利用厌氧活性污泥作产氢接种物，发酵有机质产生氢气，一般是在酸性条件下进行的。以厌氧活性污泥作接种物，有机酸为基质，在厌氧、恒温25℃、不同的pH值下，启动发酵产氢，以及监测产氢过程中的pH值变化，得出pH值过高时，有大量的甲烷生成，pH值过低时，则对产氢细菌不利，难于产氢。启动发酵产氢时，pH值不宜底于4．3，较为适宜的产氢pH值范围4．5～5．5。     

氢能制取和储存技术研究发展综述

综述了氢能制取和储存技术研究的最新发展现状。生物质制氢、太阳能热化学循环制氢、太阳能半导体光催化制氢、核能制氢等技术具有资源丰富、使用可再生能源的优点,能克服传统电解水制氢能耗高和矿物原料有限的缺点,成为提高制氢效率、实现规模生产的研究重点。加压压缩储氢技术的研究进展主要体现在改进容器材料和研发吸氯物质方面;液化储氢技术研发重点是降低能耗和成本;金属氢化物储氢技术正努力突破储氢密度低的难题。氢能制取、储存技术正在走向实用阶段,重点技术方向是以水为原料,实现大规模、经济、高效和安全地制氢储氢,推动氢能可持续和洁净的利用,促进能源安全。     

On-board hydrogen storage and production: An application of ammonia electrolysis

On-board hydrogen storage and production via ammonia electrolysis was evaluated to determine whether the process was feasible using galvanostatic studies between an ammonia electrolytic cell (AEC) and a breathable proton exchange membrane fuel cell (PEMFC). Hydrogen-dense liquid ammonia stored at ambient temperature and pressure is an excellent source for hydrogen storage. This hydrogen is released from ammonia through electrolysis, which theoretically consumes 95% less energy than water electrolysis; 1.55 Wh g⁻¹ H₂ is required for ammonia electrolysis and 33 Wh g⁻¹ H₂ for water electrolysis. An ammonia electrolytic cell (AEC), comprised of carbon fiber paper (CFP) electrodes supported by Ti foil and deposited with Pt-Ir, was designed and constructed for electrolyzing an alkaline ammonia solution. Hydrogen from the cathode compartment of the AEC was fed to a polymer exchange membrane fuel cell (PEMFC). In terms of electric energy, input to the AEC was less than the output from the PEMFC yielding net electrical energies as high as 9.7 ± 1.1 Wh g⁻¹ H₂ while maintaining H₂ production equivalent to consumption.     

A review on biomass‐based hydrogen production and potential applications

In this paper, a detailed review is presented to discuss biomass‐based hydrogen production systems and their applications. Some optimum hydrogen production and operating conditions are studied through a comprehensive sensitivity analysis on the hydrogen yield from steam biomass gasification. In addition, a hybrid system, which combines a biomass‐based hydrogen production system and a solid oxide fuel cell unit is considered for performance assessment. A comparative thermodynamic study also is undertaken to investigate various operational aspects through energy and exergy efficiencies. The results of this study show that there are various key parameters affecting the hydrogen production process and system performance. They also indicate that it is possible to increase the hydrogen yield from 70 to 107 g H₂ per kg of sawdust wood. By studying the energy and exergy efficiencies, the performance assessment shows the potential to produce hydrogen from steam biomass gasification. The study further reveals a strong potential of this system as it utilizes steam biomass gasification for hydrogen production. To evaluate the system performance, the efficiencies are calculated at particular pressures, temperatures, current densities, and fuel utilization factors. It is found that there is a strong potential in the gasification temperature range 1023–1423 K to increase energy efficiency with a hydrogen yield from 45 to 55% and the exergy efficiency with hydrogen yield from 22 to 32%, respectively, whereas the exergy efficiency of electricity production decreases from 56 to 49.4%. Hydrogen production by steam sawdust gasification appears to be an ultimate option for hydrogen production based on the parametric studies and performance assessments that were carried out through energy and exergy efficiencies. Finally, the system integration is an attractive option for better performance. Copyright © 2012 John Wiley & Sons, Ltd.     

沼气池产气率随气温地温变化规律的研究

为了准确掌握户用沼气池在不同模式条件下的产气能力,探讨其产气率率环境温度的关系,以便科学地评价其经济效益,更好地指导农户管理、使用沼气池,采用观察、记载统计方法,得到“四位一体”模式、“三结合”模式和露地池的产气量变化规律.     

Modelling the dynamic response of a solid oxide steam electrolyser to transient inputs during renewable hydrogen production

Hydrogen is regarded as a leading candidate for alternative future fuels. Solid oxide electrolyser cells (SOEC) may provide a cost-effective and green route to hydrogen production especially when coupled to a source of renewable electrical energy. Developing an understanding of the response of the SOEC stack to transient events that may occur during its operation with intermittent electricity input is essential before the realisation of this technology. In this paper, a one-dimensional (1D) dynamic model of a planar SOEC stack has been employed to study the dynamic behaviour of such an SOEC and the prospect for stack temperature control through variation of the air flow rate. Step changes in the average current density from 1.0 to 0.75, 0.5 and 0.2 A/cm² have been imposed on the stacks, replicating the situation in which changes in the supply of input electrical energy are experienced, or the sudden switch-off of the stack. Such simulations have been performed both for open-loop and closed-loop cases. The stack temperature and cell voltage are decreased by step changes in the average current density. Without temperature control via variation of the air flow rate, a sudden fall of the temperature and the cell potential occurs during all the step changes in average current density. The temperature excursions between the initial and final steady states are observed to be reduced by the manipulation of the air flow rate. Provided that the change in the average current density does not result in a transition from exothermic to endothermic operation of the SOEC, the use of the air flow rate to maintain a constant steady-state temperature is found to be successful.     

A review on the importance of operating conditions and process parameters in sonic hydrogen production

This review article discusses the operating conditions and key parameters of the sonohydrogen process, including the acoustic pressure amplitude, ultrasonic frequency and ambient bubble radius, which help achieve better sonochemical activity and higher hydrogen production rate. It also clarifies some discrepancies in the values of various operating conditions and state properties assumed and/or utilized in the literature studies. It further reviews the history of experiments available in the literature on different techniques to measure the bubble radius-versus time curve and discusses the parameters that govern the operation of the sonoreactor and the sonohydrogen process. The boundary conditions of the sonohydrogen process for the expected sonochemical activity and the acoustic bubble pressure and temperatures are comprehensively illustrated. The classifications of the acoustic cavitation bubbles are presented, followed by a discussion of the Blake cavitation threshold and its application to single bubble simulation and full sonoreactor geometries. Furthermore, a review of the predicted hot-spot temperature at different boundary conditions is demonstrated, tailed with the dependence of the sonochemical activity on the medium, including dissolved gases specific heat ratio, thermal conductivity, and thermal diffusivity. Moreover, the findings of this review emphasize the differences in the maximum bubble temperature (hot spot's temperature) for different dissolved gases.     

A study on the dynamic behavior of a sulfur trioxide decomposer for a nuclear hydrogen production

The sulfur–iodine thermochemical water-splitting cycle (S–I cycle) is one of the most promising technologies for mass H₂ production. The S–I cycle is generally divided into three sections, one of which involves a H₂SO₄ concentration and decomposition. In the sulfuric acid processing section (Section 2), H₂SO₄ is decomposed into H₂O and SO₃, and then the produced SO₃ is further decomposed into SO₂ and O₂, which takes place in a H₂SO₄ decomposer and a SO₃ decomposer, respectively. The SO₃ decomposition requires heat of a high temperature and this suggests a heat-exchanger type reactor. To understand the temperature profiles and chemical reactions through a SO₃ decomposer, a dynamic model was developed by considering the heat and material balances in partial differential forms. A model was used to size the decomposer to a proposed design basis and it was also applied to simulate the responses corresponding to the changes of the operation conditions such as increased or decreased flow rates.     

A comprehensive study of hydrogen production from ammonia borane via PdCoAg/AC nanoparticles and anodic current in alkaline medium: experimental design with response surface methodology

In this paper, the optimization of hydrogen (H₂) production by ammonia borane (NH₃BH₃) over PdCoAg/AC was investigated using the response surface methodology. Besides, the electro-oxidation of NH₃BH₃ was determined and optimized using the same method to measure its potential use in the direct ammonium boran fuel cells. Moreover, the ternary alloyed catalyst was synthesized using the chemical reduction method. The synergistic effect between Pd, Co and Ag plays an important role in enhancement of NH₃BH₃ hydrolysis. In addition, the support effect could also efficiently improve the catalytic performance. Furthermore, the effects of NH₃BH₃ concentration (0.1–50 mmol/5 mL), catalyst amount (1–30 mg) and temperature (20°C–50°C) on the rate of H₂ production and the effects of temperature (20°C–50°C), NH₃BH₃ concentration (0.05–1 mol/L) and catalyst amount (0.5–5 µL) on the electro-oxidation reaction of NH₃BH₃ were investigated using the central composite design experimental design. The implementation of the response surface methodology resulted in the formulation of four models out of which the quadratic model was adjudged to efficiently appropriate the experimental data. A further statistical analysis of the quadratic model demonstrated the significance of the model with a p-value far less than 0.05 for each model and coefficient of determination (R²) of 0.85 and 0.95 for H₂ production rate and NH₃BH₃ electrroxidation peak current, respectively.     

Design analysis and tri-objective optimization of a novel integrated energy system based on two methods for hydrogen production: By using power or waste heat

Hydrogen is rapidly turning into one of the essential energy carriers for future sustainable energy systems. The main reason for this is the possibility of off-peak excess power production and storage of renewable stations such as wind farms, photovoltaic plants, etc. For hydrogen (itself) or its sub-productions methanol, ammonia, etc. Such energy systems are so-called power2X technologies. For hydrogen and other biogases, using a fuel cell is a promising method for returning the fuel to the power grid or electric cars in the form of electricity. In this paper, a novel hybrid energy system consisting of a molten carbonate fuel cell (MCFC) and different options to generate hydrogen from the waste heat of the MCFC is investigated. The system consists of two scenarios of weather using proton exchange membrane electrolyzer (PEME) of vanadium chloride (VCL) cycle. The article presents a comprehensive thermodynamic, economic, and environmental analysis of the system optimized by tri-objective optimization (as an innovative optimization) methods. The aim of the optimization task here is to minimize the costs and emissions while maximizing efficiency. A parametric study is conducted to see the effect of different design parameters on the system's performance. Results demonstrate that fuel utilization factor, stack temperature, and current density have the most critical effect on the system performance. In addition, the system coupled with the VCL cycle exhibits better performance than the system with PEME. In addition, at the optimized point, the efficiency, cost rate, and emission become 69.28%, 3.73 ($/GJ), and 1.16 kg/kWh, respectively. In addition, the produced hydrogen in VCL and PEME are 585 kg/day and 293 kg/day respectively.     

Investigation of hydrogen production performance of chlor-alkali cell integrated into a power generation system based on geothermal resources

In present study, hydrogen production performance of chlor-alkali cell integrated into a power generation system based on geothermal resource is studied. The basic elements of the novel system are a separator, a steam power turbine, an organic Rankine cycle (ORC), an air cooled condenser, a saturated NaCl solution reservoir tank and a chlor-alkali cell. To enhance the performance of the cell, the saturated NaCl solution is heated by the waste heat from the ORC. So, this integrated system generates significant amount of electricity for the city grid and also yields three main products those are hydrogen, chlorine and sodium hydroxide. According to the parametric study, when the temperature of a geothermal resource varies from 140 to 155 °C, the electrical power generation increases from nearly 2.5 MW to 3.9 MW and hydrogen production increases from 10.5 to 21.1 kg-h. Thus, when the geothermal resource temperature of 155 °C, the energy efficiency of the system is 6.2% and the exergetic efficiency is 22.4%. As a result, the geothermal energy potential plays a key role on the integrated system performance and the hydrogen production rate.     

Effect of O2 and temperature on the catalytic performance of Ni/Al2O3 and Ni/MgAl2O4 for the dry reforming of methane (DRM)

Al₂O₃ and MgAl₂O₄ supported 10% (w/w) Ni catalysts having a dispersion of 1.5 and 2.0% are active for DRM at 600 and 750 °C. High temperature reduction of both the calcined catalysts resulted in metallic Ni being formed, suggesting strong support metal interactions. The CH₄ and CO₂ conversion during DRM are relatively constant with time-on-stream, and are higher for Ni/MgAl₂O₄ than Ni/Al₂O₃. Carbon-whiskers are also detected on both catalysts. O₂ co-feed of 2.6% (v/v) and increasing reaction temperature to 750 °C helped in decreasing the amount of carbon deposited, except for Ni/MgAl₂O₄ at 600 °C. Furthermore, higher conversions and H₂/CO ratios are achieved. It appears that on spent Ni/MgAl₂O₄ a different type of carbon species was formed, and this carbon species was difficult to remove by oxygen at 600 °C. Thus, co-feeding O₂, using an appropriate temperature, and choosing a suitable support can reduce the carbon present on the nickel catalysts during DRM.     

A study on the integration of micro‐reformer and high‐ temperature PEM fuel cell

This study presented an integration platform for a methanol reformer and high‐temperature proton exchange membrane fuel cell (PEMFC). The methanol micro‐reformer was combined with the catalytic reaction section and reforming section, whereas the catalytic reaction section with Pt catalysis maintained the constant temperature environment for a reforming process. SRM reforming results showed that 74 to 74.9% hydrogen and 23.5 to 25.7% of carbon dioxide in the mixture product, and less than 2% of carbon monoxide, was produced. Using the reforming product of low carbon monoxide concentration and the highest methanol conversion rate, a micro reformer link with a fuel cell integration experiment was performed. Results showed a high temperature PEMFC with 3 to 4 W power output under methanol flow rates of 15 ml/hr. Due to the lower hydrogen pressure supplied from the micro reformer, the fuel cell power output may become unstable. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/htj.20322     

应用于平抑风功率的燃氢燃气轮机储能系统控制策略研究

储能技术可用于提高风电并网能力,因此其储能系统及控制策略成为研究热点。提出将燃氢燃气轮机作为储能系统主要部分,低通滤波器结合模糊控制作为其平抑风功率的控制策略。通过设定储氢罐容量,对15台1.5 MW风机的历史风功率数据进行了处理。结果表明：低通滤波器结合模糊控制能有效平抑风功率至限制值,实现平抑指标,并得到储氢罐容量的设置限制;可实现储能时燃气轮机不工作,耗能时燃气轮机工作,当储氢罐容量为0.017 m³时,燃气轮机输出功率为0.1 MW。在将燃气轮机作为平抑风功率的储能系统时,需将燃气轮机的启停控制作为今后的研究重点。     

A unique study on the effect of dissolved gases and bubble temperatures on the ultrasonic hydrogen (sonohydrogen) production

Producing hydrogen via sound waves offers a tremendous opportunity for generating an energy carrier in an environmentally-friendly manner. The open literature lacks research studies concerning the effect of the dissolved gases on the ultrasonic hydrogen production process (sonohydrogen). Therefore, in this work, the effect of diluting different dissolved gases on the performance of the sonohydrogen process is studied. The present reaction kinetics mechanism consists of 19 reversible chemical reactions taking place inside the acoustic cavitation micro-bubble and is solved computationally. The results reveal that the dissolved gases have a significant effect on the chemical mechanism of the water vapor dissociation. The present study shows that using carbon dioxide as a dissolved gas within the sonohydrogen process enhances the hydrogen production rate. Two different bubble compositions are investigated; H₂O/O₂ and H₂O/CO₂ bubbles. In the case of the H₂O/O₂ bubble, the energy efficiency is calculated, and its value ranges between 1.05 and 1.63 μmol/kWh, depending on the bubble's temperature. However, in the case of the H₂O/CO₂ bubble, the hydrogen production shows a considerable improvement with energy efficiency in the range 22.26–34.98 μmol/kWh. This is due to the lower thermal conductivity, higher heat capacity, and lower thermal diffusivity of the composition of water vapor and carbon dioxide.