Chinese Taipei

The effects of baking on the mechanical properties and fracture characteristics of low-carbon boron (10B21) steel screws were investigated. Fracture torque tests and hydrogen content analysis were performed on baked screws to evaluate hydrogen embrittlement (HE) susceptibility. The diffusible hydrogen content within 10B21 steel dominated the fracture behavior of the screws. The fracture torque of 10B21 screws baked for a long duration was affected by released hydrogen. Secondary ion mass spectroscopy (SIMS) result showed that hydrogen content decreased with increasing baking duration and thus the HE susceptibility of 10B21 screws improved. Diffusible hydrogen promoted crack propagation in high-stress region. The HE of 10B21 screws can be prevented by long-duration baking.

The effect of metastable austenite on the hydrogen embrittlement (HE) of cold-rolled (30% reduction in thickness) 301 stainless steel (SS) was investigated. Cold-rolled (CR) specimens were hydrogen-charged in an autoclave at 300 or 450 °C under a pressure of 10 MPa for 160 h before tensile tests. Both ordinary and notched tensile tests were performed in air to measure the tensile properties of the non-charged and charged specimens. The results indicated that cold rolling caused the transformation of austenite into α′ and ε-martensite in the 301 SS. Aging at 450 °C enhanced the precipitation of M23C6 carbides G and σ phases in the cold-rolled specimen. In addition the formation of α′ martensite and M23C6 carbides along the grain boundaries increased the HE susceptibility and low-temperature sensitization of the 450 °C-aged 301 SS. In contrast the grain boundary α′-martensite and M23C6 carbides were not observed in the as-rolled and 300 °C-aged specimens

Setting up and operating a hydrogen refueling station is a critical part of current drive for fuel cell vehicles. In setting up a hydrogen refueling station (HRS) the investor concerns of the capacity of HRS the quality of hydrogen the capital requirement of the station and the modes of hydrogen supply; interestingly the supply modes of hydrogen further influences the safety of the station the cost of hydrogen the energy consumption of supply and the area of hydrogen supply section in a station. Hydrogen can be supplied to a HRS by the procurement of the merchant hydrogen from a central source with the central hydrogen supply mode (CHSM) or by an onsite production of hydrogen in the distributed hydrogen supply mode (DHSM). In this presentation the above factors are evaluated with respect to these two supply modes of hydrogen. It is concluded that the lower hydrogen cost and the smaller site area as well as the safer aspect of the public concern of safety can be realized with the choice of the distributed hydrogen supply mode by an onsite hydrogen production from methanol.

Methanol is regarded as an important feedstock for hydrogen production due to its high energy density and superior transportability. A tubular packed-bed reactor performing the methanol steam reforming (MSR) process was modeled by adopting computational fluid dynamics (CFD) software to analyze its performance. Kinetic parameters of the reactions were adjusted according to the literatures and our previous experimental results. The methanol conversion the hydrogen production rate and the CO concentration in the produced mixture were evaluated by considering different levels of the length and temperature of the catalyst bed the steam-to-carbon ratio and the space velocity of the feedstocks. Moreover the correlation between the dimensionless parameter Damköhler number and the methanol conversion was also investigated.

In our previous studies of a plasma reformer system the effects of temperature of the reactants and input voltage have not been considered. In the present investigation the plasma reformer system has been modified to study the influence of the reactants’ temperature and input voltage on hydrogen production experimentally. The plasma reformer system includes a supersonic atomizer a plasma generator and a controlling device. In the experiment the operating parameters include the temperature of the reactants and the input voltage. The temperature of the reactants varies from 25 °C to 50 °C and the input voltage ranges from 12.5 V to 14.5 V. Results show that the increase in temperature of the reactants and input voltage will improve the production of hydrogen. In addition the improvement of heating on the reactants shows significant influence on hydrogen production.

Power-to-fuel systems via solid-oxide electrolysis are promising for storing excess renewable electricity by efficient electrolysis of steam (or co-electrolysis of steam and CO₂) into hydrogen (or syngas) which can be further converted into synthetic fuels with plant-wise thermal integration. Electrolysis stack performance and durability determine the system design performance and long-term operating strategy; thus solid-oxide electrolyzer based power-to-fuels were investigated from the stack to system levels. At the stack level the data from a 6000-h stack testing under laboratory isothermal conditions were used to calibrate a quasi-2D model which enables to predict practical isothermal stack performance with reasonable accuracy. Feasible stack operating windows meeting various design specifications (e.g. specific syngas composition) were further generated to support the selection of operating points. At the system level with the chosen similar stack operating points various power-to-fuel systems including power-to-hydrogen power-to-methane power-to-methanol (dimethyl ether) and power-to-gasoline were compared techno-economically considering system-level heat integration. Several operating strategies of the stack were compared to address the increase in stack temperature due to degradation. The modeling results show that the system efficiency for producing H₂ methane methanol/dimethyl ether and gasoline decreases sequentially from 94% (power-to-H₂) to 64% (power-to-gasoline) based on a higher heating value. Co-electrolysis which allows better heat integration can improve the efficiency of the systems with less exothermic fuel-synthesis processes (e.g. methanol/dimethyl ether) but offers limited advantages for power-to-methane and power-to-gasoline systems. In a likely future scenario where the growing amount of electricity from renewable sources results in increasing periods of a negative electricity price solid oxide electrolyser based power-to-fuel systems are highly suitable for levelling the price fluctuations in an economic way.

In this study an energy exergy and environmental (3E) analyses of a plasma-assisted hydrogen production process from microalgae is investigated. Four different microalgal biomass fuels namely raw microalgae (RM) and three torrefied microalgal fuels (TM200 TM250 and TM300) are used as the feedstock for steam plasma gasification to generate syngas and hydrogen. The effects of steam-tobiomass (S/B) ratio on the syngas and hydrogen yields and energy and exergy efficiencies of plasma gasification _{(hEn;PG hEx;PG)} and hydrogen production_{(hEn;H2 hEx;H2 )} are taken into account. Results show that the optimal S/B ratios of RM TM200 TM250 and TM300 are 0.354 0.443 0.593 and 0.760 respectively occurring at the carbon boundary points (CBPs) where the maximum values of _{hEn;PG hEx;PG hEn;H2} and _hEx;H2 are also achieved. At CBPs torrefied microalgae as feedstock lower the_{hEn;PG hEx;PG hEn;H2} and _hEx;H2 because of their improved calorific value after undergoing torrefaction and the increased plasma energy demand compared to the RM. However beyond CBPs the torrefied feedstock displays better performance. A comparative life cycle analysis indicates that TM300 exhibits the highest greenhouse gases (GHG) emissions and the lowest net energy ratio (NER) due to the indirect emissions associated with electricity consumption.

In recent years increasing concerns regarding the energy costs and environmental effects of urban motorcycle use have spurred the development of hydrogen-electric motorcycles in Taiwan. Although gasoline-powered motorcycles produce substantial amounts of exhaust and noise pollution hydrogen-electric motorcycles are highly energy-efficient relatively quiet and produce zero emissions features that suggest their great potential to reduce the problems currently associated with the use of motorcycles in city environments. This study identified the significant external variables that affect consumers’ purchase intentions toward using hydrogen-electric motorcycles. A questionnaire method was employed with a total of 300 questionnaires distributed and 233 usable questionnaires returned yielding a 78% overall response rate. Structural equation modeling (SEM) was applied to test the research hypothesis. The research concluded that (1) product knowledge positively influenced purchase intentions but negatively affected the perceived risk; (2) perceived quality via hydrogen-electric motorcycles positively influenced the perceived value but negatively affected the perceived risk; (3) perceived risk negatively affected the perceived value; and (4) the perceived value positively affected purchase intentions. This study can be used as a reference for motorcycle manufacturers when planning their marketing strategies.

As environmental awareness among the public gradually improves it is predicted that the trend of green consumption will make green products enter the mainstream market. Hydrogen-electric motorcycles with eco-friendly and energy-efficient characteristics have great advantages for development. However as a type of innovative product hydrogen-electric motorcycles require further examination with regard to consumer acceptance and external variables of the products. In this study consumer behavioral intention (BI) for the use of hydrogen-electric motorcycles and its influencing factors are discussed using innovation resistance as the basis and environmental concern as the adjusting variable. Consumers’ willingness-to-pay (WTP) for hydrogen-electric motorcycles is estimated using the contingent valuation method (CVM). The results found that (1) perception barriers viz. usage barrier value barrier risk barrier tradition barrier and price barrier are statistically significant whereas image barrier is not; (2) a high degree of environmental concern will reduce the consumers’ innovation resistance to the hydrogen-electric motorcycles; (3) up to 94.79% of the respondents of the designed questionnaire suggested that the promotion of hydrogen-electric motorcycles requires a subsidy of 21.9% of the total price from the government. The mean WTP of consumers for the purchase of hydrogen-electric motorcycles is 10–15% higher than that of traditional motorcycles.

This paper discusses the optimization of hybrid power systems which consist of solar cells wind turbines fuel cells hydrogen electrolysis chemical hydrogen generation and batteries. Because hybrid power systems have multiple energy sources and utilize different types of storage we first developed a general hybrid power model using the Matlab/SimPowerSystemTM and then tuned model parameters based on the experimental results. This model was subsequently applied to predict the responses of four different hybrid power systems for three typical loads without conducting individual experiments. Furthermore cost and reliability indexes were defined to evaluate system performance and to derive optimal system layouts. Finally the impacts of hydrogen costs on system optimization was discussed. In the future the developed method could be applied to design customized hybrid power systems.

Consumption of fossil fuels especially in transport and energy-dependent sectors has led to large greenhouse gas production. Hydrogen is an exciting energy source that can serve our energy purposes and decrease toxic waste production. Decomposition of methane yields hydrogen devoid of COx components thereby aiding as an eco-friendly approach towards large-scale hydrogen production. This review article is focused on hydrogen production through thermocatalytic methane decomposition (TMD) for hydrogen production. The thermodynamics of this approach has been highlighted. Various methods of hydrogen production from fossil fuels and renewable resources were discussed. Methods including steam methane reforming partial oxidation of methane auto thermal reforming direct biomass gasification thermal water splitting methane pyrolysis aqueous reforming and coal gasification have been reported in this article. A detailed overview of the different types of catalysts available the reasons behind their deactivation and their possible regeneration methods were discussed. Finally we presented the challenges and future perspectives for hydrogen production via TMD. This review concluded that among all catalysts nickel ruthenium and platinum-based catalysts show the highest activity and catalytic efficiency and gave carbon-free hydrogen products during the TMD process. However their rapid deactivation at high temperatures still needs the attention of the scientific community.

The rotary engine (RE) is a potential power plant for unmanned aerial vehicles (UAVs) and automobiles because of its structural and design merits. However it has some serious drawbacks such as frequent maintenance requirements and excessive fuel consumption. This review paper presents the current status of hydrogen-fueled rotary engine (HRE) technology and identifies the existing research and development gaps in combustion efficiency and performance of this engine that might benefit transportation sector. Focusing primarily on the research from past ten years the crucial challenges encountered in hydrogen-powered rotary engines have been reviewed in terms of knock hydrocarbon (HC) emissions and seal leakages. The paper identifies the recent advances in design concepts and production approaches used in hydrogen-fueled rotary engines such as geometric models of trochoid profiles port configurations fuel utilization systems and currently available computational fluid dynamics (CFD) tools. This review article is an attempt to collect and organize literature on existing design methods up to date and provide recommendations for further improvements in RE technology.

Human activities have exacerbated global greenhouse effects resulting in extreme climate changes that have caused disasters and food and water shortages in recent years. Transport activities are the one of the main causes of global greenhouse gas (GHG) emissions. Therefore policy makers must develop some strategies to reduce GHG emissions. One of the Taiwan’s transportation policies intended to reduce CO2 emissions is to replace all traditional diesel fuel urban buses with alternative energy buses. This paper uses a case study of bus route NO. 2 in Tainan City and follows the international standard ISO/TS 14067 and PAS2050 to measure the carbon footprints of different energy buses. The purpose is to measure the environmental benefits of alternative energy buses. The results of the bus carbon footprints from high to low were LNG buses 63.14g CO2e/pkm; traditional diesel buses 54.6g CO2e/pkm; liquefied petroleum gas buses 47.4g CO2e/pkm; plug-in electric buses 37.82g CO2e/pkm and hydrogen fuel cell bus es 29.17g CO2e/pkm respectively. It was also found that the use of hydrogen fuel cell buses would potentially reduce CO2e emissions in Tainan City by 1244081 tons which at this time is only city bus No. 2. If all the Taiwan city buses were switched to hydrogen fuel cell buses this would potentially reduce CO2e by 227832.39 tons. The effect of the reduction in carbon emissions from the use of hydrogen fuel cells buses in all Taiwanese urban areas is the equivalent of planting 22.78 million trees. It is thus suggested that the government use hydrogen fuel cell buses as the future of the country’s major alternative energy buses since they are the most environmentally friendly alternative to reducing CO2 emissions.

Hydrogen embrittlement in metals (HE) is a serious challenge for the use of high strength materials in engineering practice and a major barrier to the use of hydrogen for global decarbonization. Here we describe the factors and variables that determine HE susceptibility and provide an overview of the latest understanding of HE mechanisms. We discuss hydrogen uptake and how it can be managed. We summarize hydrogen trapping and the techniques used for its characterization. We also review literature that argues that hydrogen trapping can be used to decrease HE susceptibility. We discuss the future research that is required to advance the understanding of HE and hydrogen trapping and to develop HE-resistant alloys.