Publications

In this fourth episode Simon Buckley and Matthew Moss from Innovate UK KTN are exploring the use of hydrogen in the global maritime industry alongside their special guest Chester Lewis Business Development Manager at Ryze Hydrogen.

This podcast can be found on their website

To address the limitations of conventional single-stack fuel cell hybrid systems using equivalent hydrogen consumption strategies this study proposes a multi-stack energy management strategy incorporating fuel cell health degradation. Leveraging a fuel cell efficiency decay model and lithium-ion battery cycle life assessment power distribution is reformulated as an equivalent hydrogen consumption optimization problem with stack degradation constraints. A hybrid Genetic Algorithm–Particle Swarm Optimization (GAPSO) approach achieves global optimization. The experimental results demonstrate that compared with the Frequency Decoupling (FD) method the GA-PSO strategy reduces hydrogen consumption by 7.03 g and operational costs by 4.78%; compared with the traditional Particle Swarm Optimization (PSO) algorithm it reduces hydrogen consumption by 3.61 g per operational cycle and decreases operational costs by 2.66%. This strategy ensures stable operation of the marine power system while providing an economically viable solution for hybrid-powered vessels.

The automotive industry sees hydrogen-powered fuel cell(FC) drives as a promising option with a high range and shortrefueling time. Current research aims to increase the profitabil-ity of the fuel cell system by reducing hydrogen consumption.This study suggests the use of an electrochemical hydrogencompressor (EHC) for hydrogen recirculation. Compared tomechanical compressors the EHC is very efficient due to thealmost isothermal conditions and due to its modular structurecan only take up a minimal amount of space in vehicles. Inaddition gas separation and purification of the hydrogentakes place in an EHC which is a significant advantage overthe standard recirculation with a blower or a jet pump. Thehigh purity of the hydrogen at the cathode outlet of the EHCalso increased partial pressure of the hydrogen at the fuel cellinlet and its efficiency. The study carried out shows that repla-cing the blower with the EHC reduces the hydrogen loss bypurging by up to ~95% and the efficiency of the FC systemcould be further improved. Thus the EHC has a great poten-tial for recycling hydrogen in FC systems in the automotiveindustry and is a great alternative to the current blower.

Turquoise hydrogen is produced from methane cracking a cleaner alternative to steam methane reforming. This study looks at two proposed systems based on solar methane cracking for low-carbon fuel production. The systems utilize different pathways to convert the hydrogen into a suitable form for transportation and utilize the carbon solid by-product. A direct carbon fuel cell is integrated to utilize the carbon and capture the CO2 emissions. The CO2 generated is utilized for fuel production using CO2 hydrogenation or co-electrolysis. An advanced exergetic analysis is conducted on these systems using Aspen plus simulations of the process. The exergetic efficiency waste exergy ratio exergy destruction ratio exergy recoverability ratio environmental effect factor and the exergetic sustainability index were determined for each system and the subsystems. Solar methane cracking was found to have an environmental effect factor of 0.08 and an exergetic sustainability index of 12.27.

The present paper deals with the investigation at conceptual level of the performance of short–medium-range aircraft with hydrogen propulsion. The attention is focused on the relationship between figures of merit related to transport capability such as passenger capacity and flight range and the parameters which drive the design of liquid hydrogen tanks and their integration with a given aircraft geometry. The reference aircraft chosen for such purpose is a box-wing short–mediumrange airplane the object of study within a previous European research project called PARSIFAL capable of cutting the fuel consumption per passenger-kilometre up to 22%. By adopting a retrofitting approach non-integral pressure vessels are sized to fit into the fuselage of the reference aircraft under the assumption that the main aerodynamic flight mechanic and structural characteristics are not affected. A parametric model is introduced to generate a wide variety of fuselage-tank cross-section layouts from a single tank with the maximum diameter compatible with a catwalk corridor to multiple tanks located in the cargo deck and an assessment workflow is implemented to perform the structural sizing of the tanks and analyse their thermodynamic behaviour during the mission. This latter is simulated with a time-marching approach that couples the fuel request from engines with the thermodynamics of the hydrogen in the tanks which is constantly subject to evaporation and depending on the internal pressure vented-out in gas form. Each model is presented in detail in the paper and results are provided through sensitivity analyses to both the technologic parameters of the tanks and the geometric parameters influencing their integration. The guidelines resulting from the analyses indicate that light materials such as the aluminium alloy AA2219 for tanks’ structures and polystyrene foam for the insulation should be selected. Preferred values are also indicted for the aspect ratios of the vessel components i.e. central tube and endcaps as well as suggestions for the integration layout to be adopted depending on the desired trade-off between passenger capacity as for the case of multiple tanks in the cargo deck and achievable flight ranges as for the single tank in the section.

Severe accidents in nuclear power plants are potentially dangerous to both humans and the environment. To prevent and/or mitigate the consequences of these accidents it is paramount to have adequate accident management measures in place. During a severe accident combustible gases — especially hydrogen and carbon monoxide — can be released in significant amounts leading to a potential explosion risk in the nuclear containment building. These gases need to be managed to avoid threatening the containment integrity which can result in the releases of radioactive material into the environment. The main objective of the AMHYCO project is to propose innovative enhancements in the way combustible gases are managed in case of a severe accident in currently operating reactors. For this purpose the AMHYCO project pursues three specific activities including experimental investigations of relevant phenomena related to hydrogen / carbon monoxide combustion and mitigation with PARs (Passive Autocatalytic Recombiners) improvement of the predictive capabilities of analysis tools used for explosion hazard evaluation inside the reactor containment as well as enhancement of the Severe Accident Management Guidelines (SAMGs) with respect to combustible gases risk management based on theoretical and experimental results. Officially launched on 1 October 2020 AMHYCO is an EU-funded Horizon 2020 project that will last 4 years from 2020 to 2024. This international project consists of 12 organizations (six from European countries and one from Canada) and is led by the Universidad Politécnica de Madrid (UPM). AMHYCO will benefit from the worldwide experts in combustion science accident management and nuclear safety in its Advisory Board. The paper will give an overview of the work program and planned outcome of the project.

NREL has been developing compliance verification tools for allowable hydrogen levels prescribed by the Global Technical Regulation Number 13 (GTR-13) for hydrogen fuel cell electric vehicles (FCEVs). As per GTR-13 FCEV exhaust is to remain below 4 vol% H2 over a 3-second moving average and shall not at any time exceed 8 vol% H2 and that this requirement is to be verified with an analyzer that has a response time of less than 300 ms. To be enforceable a means to verify regulatory requirements must exist. In response to this need NREL developed a prototype analyzer that meets the GTR metrological requirements for FCEV exhaust analysis. The analyzer was tested on a commercial fuel cell electric vehicle (FCEV) under simulated driving conditions using a chassis dynamometer at the Emissions Research and Measurement Section of Environment and Climate Change Canada and FCEV exhaust was successfully profiled. Although the prototype FCEV Exhaust Analyzer met the metrological requirements of GTR-13 the stability of the hydrogen sensor was adversely impacted by condensed water in the sample gas. FCEV exhaust is at an elevated temperature and nearly saturated with water vapor. Furthermore condensed water is present in the form of droplets. Condensed water in the sample gas collected from FCEV exhaust can accumulate on the hydrogen sensing element which would not only block access of hydrogen to the sensing element but can also permanently damage the sensor electronics. In the past year the design of the gas sampling system was modified to mitigate against the transport of liquid water to the sensing element. Laboratory testing confirmed the effectiveness of the modified sampling system water removal strategy while maintaining the measurement range and response time required by GTR-13. Testing of the upgraded analyzer design on an FCEV operating on a chassis dynamometer is scheduled for the summer of 2021.

The HyDeploy project [1] has undertaken an extensive research programme to assess safety and performance of the existing UK gas appliances population fueled with natural gas / hydrogen admixtures (hydrogen blended gas). The first stage of this work [2] focused on well maintained and normally functioning appliances. This work demonstrated that unmodified gas appliances can operate safely with hydrogen blended gas (up to 20 vol% hydrogen) and the key hazard areas of carbon monoxide (CO) production light back and flame out and the operation of flame failure devices are unaffected. It is widely recognized that due to aging and variable degrees of maintenance that the combustion performance of a gas appliance will depreciate over time. In extreme cases this can lead to situations where high levels of CO may be released back into the dwelling resulting in CO poisoning to the occupants. To obtain a universal appreciation of the effect of hydrogen addition on the safety and performance of all gas appliances operation under sub optimal conditions is required and therefore it is important that the operation of malfunctioning appliances fuelled with hydrogen blended gas is assessed. A review of failure modes identified six key scenarios where the composition of the fuel gas may lead to changes in safety performance - these primarily related to the resulting composition of the flue gas but also included delayed ignition. Gas appliance faults that will increase the CO production were tested through a series of experiments to simulate fault conditions and assess the effect of hydrogen blended gas. The fault modes examined included linting flame chilling incorrect appliance set up and modification of gas valve operation. The programme utilized six different appliances tested with three methane-hydrogen fuel blends (containing 0 20 and 28.4 vol% hydrogen). In all cases the switch to hydrogen blended gas reduced CO production. The change in CO production when using hydrogen blended gas is a consequence of a decrease in the theoretical air requirement to achieve complete combustion. In some cases the amount of CO produced was identical to the nonfault baseline performance on methane thereby fully mitigating the consequence of the malfunction. In the case of very high CO production a 90% reduction was recorded when using 20 vol% hydrogen blended gas. In situations such as non-optimal boiler set up the addition of hydrogen to the gas supply would prevent the production of high levels of CO. The findings here together with the results from HyDeploy 1 [2] indicate that the safety and performance of unmodified existing UK gas appliances are not detrimentally affected when using hydrogen blended gas. Furthermore the addition of hydrogen to the fuel gas has been shown to reduce CO production under fault conditions therefore the introduction of hydrogen into the gas network may serve to mitigate the hazard posed by existing faulty appliances that are producing elevated levels of CO.

Biomaterials attract a lot of attention as next-generation materials. Especially in the energy field fuel cells based on biomaterials can further develop clean next-generation energy and are focused on with great interest. In this study solid-state hydrogen fuel (PSII–chitin composite) composed of the photosystem II (PSII) and hydrated chitin composite was successfully created. Moreover a biofuel cell consisting of the electrolyte of chitin and the hydrogen fuel using the PSII– chitin composite was fabricated and its characteristic feature was investigated. We found that proton conductivity in the PSII–chitin composite increases by light irradiation. This result indicates that protons generate in the PSII–chitin composite by light irradiation. It was also found that the biofuel cell using the PSII–chitin composite hydrogen fuel and the chitin electrolyte exhibits the maximum power density of 0.19 mW/cm2 . In addition this biofuel cell can drive an LED lamp. These results indicate that the solid-state biofuel cell based on the bioelectrolyte “chitin” and biofuel “the PSII–chitin composite” can be realized. This novel solid-state fuel cell will be helpful to the fabrication of next-generation energy.

Hydrogen can be generated in situ within reservoirs containing hydrocarbons through chemical reactions. This technology could be a possible solution for low-emission hydrogen production due to of simultaneous CO2 storage. In gas fields it is possible to carry out the catalytic methane conversion (CMC) if sufficient amounts of steam catalyst and heat are ensured in the reservoir. There is no confirmation of the CMC’s feasibility at relatively low temperatures in the presence of core (reservoir rock) material. This study introduces the experimental results of the first part of the research on in situ hydrogen generation in the Promyslovskoye gas field. A set of static experiments in the autoclave reactor were performed to study the possibility of hydrogen generation under reservoir conditions. It was shown that CMC can be realized in the presence of core and ex situ prepared Ni-based catalyst under high pressure up to 207 atm but at temperatures not lower than 450 ◦C. It can be concluded that the crushed core model improves the catalytic effect but releases carbon dioxide and light hydrocarbons which interfere with the hydrogen generation. The maximum methane conversion rate to hydrogen achieved at 450 ◦C is 5.8%