Publications

This paper aims at the development and validation of a computational fluid dynamic (CFD) model for simulations of the refuelling process through the entire equipment of the hydrogen refuelling station (HRS). The absence of such models hinders the design of inherently safer refuelling protocols for an arbitrary combination of HRS equipment hydrogen storage parameters and environmental conditions. The CFD model is validated against the complete process of refuelling lasting 195s in Test No.1 performed by the National Renewable Energy Laboratory (NREL). The test equipment includes high-pressure tanks of HRS pressure control valve (PCV) valves pipes breakaway hose and nozzle all the way up to three onboard tanks. The model accurately reproduced hydrogen temperature and pressure through the entire line of HRS equipment. A standout feature of the CFD model distinguishing it from simplified models is the capability to predict temperature non-uniformity in onboard tanks a crucial factor with significant safety implications.

This study aims to explore the techno-economic potential of harnessing waste heat from a Small Modular Reactor (SMR) to fuel Direct Air Carbon Capture (DACC) and High Temperature Steam Electrolysis (HTSE) technologies. The proposed system’s material flows and energy demands are modelled via the ASPEN Plus v12.1 where results are utilised to provide estimates of the Levelised Cost of DACC (LCOD) and Levelised Cost of Hydrogen (LCOH). The majority of thermal energy and electrical utilities are assumed to be supplied directly by the SMR. A sensitivity analysis is then performed to investigate the effects of core operational parameters of the system. Key results indicate levelised costs of 4.66 $/kgH2 at energy demands of 34.37 kWh/kgH2 and 0.02 kWh/kgH2 thermal for HTSE hydrogen production and 124.15 $/tCO2 at energy demands of 31.67 kWh/tCO2 and 126.33 kWh/tCO2 thermal for carbon capture; parameters with most impact on levelised costs are air intake and steam feed for LCOD and LCOH respectively. Both levelised costs i.e. LCOD and LCOH would decrease with the production scale. The study implies that an integrated system of DACC and HTSE provided the best cost-benefit results however the cost-benefit analysis is heavily subjective to geography politics and grid demand.

Mitigation of carbon dioxide (CO2) emission has been a worldwide concern. Decreasing CO2 emission by converting it into higher value products such as methanol can be a promising way. However hydrogen (H2) cost and availability are one of key barriers to CO2 conversion. Ethanol can be a sustainable source for H2 due to its renewable nature and easy conversion to H2-rich gas mixtures through ethanol steam reforming process. Nevertheless steam reforming of ethanol generates CO2. Hence this research is focused on different methods of H2 productions about a 1665.47 t/y from ethanol for supplying to methanol plants was performed using Aspen PLUS V10. The ethanol steam reforming process required the lowest required ethanol feed for a certain amount of H2. In contrast the ethanol steam reforming process presented significant amount of CO2 emission from reaction and electricity consumption. But the ethanol dehydrogenation of ethanol not only generates H2 without CO2 emission from the reaction but also ethyl acetate or acetaldehyde which are value chemicals. However ethanol dehydrogenation processes in case II and III presented relatively higher cost because by-products (ethyl acetate or acetaldehyde) were rather difficult to be separated.

In this paper we aim to analyse the impact of hydrogen production decarbonisation and electrification scenarios on the infrastructure development generation mix CO2 emissions and system costs of the European power system considering the retrofit of the natural gas infrastructure. We define a reference scenario for the European power system in 2050 and use scenario variants to obtain additional insights by breaking down the effects of different assumptions. The scenarios were analysed using the European electricity market model COMPETES including a proposed formulation to consider retrofitting existing natural gas networks to transport hydrogen instead of methane. According to the results 60% of the EU’s hydrogen demand is electrified and approximately 30% of the total electricity demand will be to cover that hydrogen demand. The primary source of this electricity would be non-polluting technologies. Moreover hydrogen flexibility significantly increases variable renewable energy investment and production and reduces CO2 emissions. In contrast relying on only electricity transmission increases costs and CO2 emissions emphasising the importance of investing in an H2 network through retrofitting or new pipelines. In conclusion this paper shows that electrifying hydrogen is necessary and cost-effective to achieve the EU’s objective of reducing long-term emissions.

The analysis aims to determine the most efficient and cost-effective way of providing power to a remote site. The two primary sources of power being considered are photovoltaics and small wind turbines while the two potential storage media are a battery bank and a hydrogen storage fuel cell system. Subsequently the hydrogen is stored within a reservoir and employed as required by the fuel cell. This strategy offers a solution for retaining surplus power generated during peak production phases subsequently utilizing it during periods when the renewable power sources are generating less power. To evaluate the performance of the hydrogen storage system the analysis included a sensitivity analysis of the wind speed and the cost of the hydrogen subsystem. In this analysis the capital and replacement costs of the electrolyzer and hydrogen storage tank were linked to the fuel cell capital cost. As the fuel cell cost decreases the cost of the electrolyzer and hydrogen tank also decreases. The optimal system type graph showed that the hydrogen subsystem must significantly decrease in price to become competitive with the battery bank.

Hydrogen has become a prospective energy carrier for a cleaner more sustainable economy offering carbon-free energy to reduce reliance on fossil fuels and address climate change challenges. However hydrogen production faces significant technological and economic hurdles that must be overcome to reveal its highest potential. This study focused on evaluating the economics and technoeconomic resilience of two large-scale hydrogen production routes from African palm empty fruit bunches (EFB) by indirect gasification. Computer-aided process engineering (CAPE) assessed multiple scenarios to identify bottlenecks and optimize economic performance indicators like gross profits including depreciation after-tax profitability payback period and net present value. Resilience for each route was also assessed considering raw material costs and the market price of hydrogen in relation to gross profits and after-tax profitability. Route 1 achieved a gross profit (DGP) of USD 47.12 million and a profit after taxes (PAT) of USD 28.74 million while Route 2 achieved a DGP of USD 46.53 million and a PAT of USD 28.38 million. The results indicated that Route 2 involving hydrogen production through an indirect gasification reactor with a Selexol solvent unit for carbon dioxide removal demonstrated greater resilience in terms of raw material costs and product selling price.

Increasingly stringent sustainability and decarbonization objectives drive investments in adopting environmentally friendly low and zero-carbon fuels. This study presents a comparative framework of green hydrogen green ammonia and green methanol production and application in a clear context. By harnessing publicly available data sources including from the literature this research delves into the evaluation of green fuels. Building on these insights this study outlines the production process application and strategic pathways to transition into a greener economy by 2050. This envisioned transformation unfolds in three progressive steps: the utilization of green hydrogen green ammonia and green methanol as a sustainable fuel source for transport applications; the integration of these green fuels in industries; and the establishment of mechanisms for achieving the net zero. However this research also reveals the formidable challenges of producing green hydrogen green ammonia and green methanol. These challenges encompass technological intricacies economic barriers societal considerations and far-reaching policy implications necessitating collaborative efforts and innovative solutions to successfully develop and deploy green hydrogen green ammonia and green methanol. The findings unequivocally demonstrate that renewable energy sources play a pivotal role in enabling the production of these green fuels positioning the global transition in the landscape of sustainable energy.

The widespread use of fossil fuels in automobiles has become a concern particularly in light of recent frequent natural disasters prompting a shift towards eco-friendly vehicles to mitigate greenhouse gas emissions. This shift is evident in the rapidly increasing registration rates of hydrogen vehicles. However with the growing presence of hydrogen vehicles on roads a corresponding rise in related accidents is anticipated posing new challenges for first responders. In this study computational fluid dynamics analysis was performed to develop effective response strategies for first responders dealing with high-pressure hydrogen gas leaks in vehicle accidents. The analysis revealed that in the absence of blower intervention a vapor cloud explosion from leaked hydrogen gas could generate overpressure exceeding 13.8 kPa potentially causing direct harm to first responders. In the event of a hydrogen vehicle accident requiring urgent rescue activities the appropriate response strategy must be selected. The use of blowers can aid in developing a variety of strategies by reducing the risk of a vapor cloud explosion. Consequently this study offers a tailored response strategy for first responders in hydrogen vehicle leak scenarios emphasizing the importance of situational assessment at the incident site.

Compression ignition engines will still be predominant in the naval sector: their high efficiency high torque and heavy weight perfectly suit the demands and architecture of ships. Nevertheless recent emission legislations impose limitations to the pollutant emissions levels in this sector as well. In addition to post-treatment systems it is necessary to reduce some pollutant species and therefore the study of combustion strategies and new fuels can represent valid paths for limiting environmental harmful emissions such as CO2 . The use of methane in dual fuel mode has already been implemented on existent vessels but the progressive decarbonization will lead to the utilization of carbon-neutral or carbon-free fuels such as in the last case hydrogen. Thanks to its high reactivity nature it can be helpful in the reduction of exhaust CH4 . On the contrary together with the high temperatures achieved by its oxidation hydrogen could cause uncontrolled ignition of the premixed charge and high emissions of NOx. As a matter of fact a source of ignition is still necessary to have better control on the whole combustion development. To this end an optimal and specific injection strategy can help to overcome all the before-mentioned issues. In this study three-dimensional numerical simulations have been performed with the ANSYS Forte® software (version 19.2) in an 8.8 L dual fuel engine cylinder supplied with methane hydrogen or hydrogen–methane blends with reference to experimental tests from the literature. A new kinetic mechanism has been used for the description of diesel fuel surrogate oxidation with a set of reactions specifically addressed for the low temperatures together with the GRIMECH 3.0 for CH4 and H2 . This kinetics scheme allowed for the adequate reproduction of the ignition timing for the various mixtures used. Preliminary calculations with a one-dimensional commercial code were performed to retrieve the initial conditions of CFD calculations in the cylinder. The used approach demonstrated to be quite a reliable tool to predict the performance of a marine engine working under dual fuel mode with hydrogen-based blends at medium load. As a result the system modelling shows that using hydrogen as fuel in the engine can achieve the same performance as diesel/natural gas but when hydrogen totally replaces methane CO2 is decreased up to 54% at the expense of the increase of about 76% of NOx emissions.

The production of hydrogen to be used as an alternative renewable energy has been widely explored. Among various methods for producing hydrogen from hydrocarbons methane decomposition is suitable for generating hydrogen with zero greenhouse gas emissions. The use of high temperatures as a result of strong carbon and hydrogen (C–H) bonds may be reduced by utilizing a suitable catalyst with appropriate catalyst support. Catalysts based on transition metals are preferable in terms of their activeness handling and low cost in comparison with noble metals. Further development of catalysts in methane decomposition has been investigated. In this review the recent progress on methane decomposition in terms of catalytic materials preparation method the physicochemical properties of the catalysts and their performance in methane decomposition were presented. The formation of carbon as part of the reaction was also discussed.