Production & Supply Chain
Boosting Photocatalytic Hydrogen Production from Water by Photothermally Induced Biphase Systems
Feb 2021
Publication
Solar-driven hydrogen production from water using particulate photocatalysts is considered the most economical and effective approach to produce hydrogen fuel with little environmental concern. However the efficiency of hydrogen production from water in particulate photocatalysis systems is still low. Here we propose an efficient biphase photocatalytic system composed of integrated photothermal–photocatalytic materials that use charred wood substrates to convert liquid water to water steam simultaneously splitting hydrogen under light illumination without additional energy. The photothermal–photocatalytic system exhibits biphase interfaces of photothermally-generated steam/photocatalyst/hydrogen which significantly reduce the interface barrier and drastically lower the transport resistance of the hydrogen gas by nearly two orders of magnitude. In this work an impressive hydrogen production rate up to 220.74 μmol h−1 cm−2 in the particulate photocatalytic systems has been achieved based on the wood/CoO system demonstrating that the photothermal–photocatalytic biphase system is cost-effective and greatly advantageous for practical applications.
Hydrogen‐Rich Gas Production from Two‐Stage Catalytic Pyrolysis of Pine Sawdust with Calcined Dolomite
Jan 2022
Publication
Tao Xu,
Jue Xu and
Yongping Wu
The potential of catalytic pyrolysis of biomass for hydrogen and bio‐oil production has drawn great attention due to the concern of clean energy utilization and decarbonization. In this paper the catalytic pyrolysis of pine sawdust with calcined dolomite was carried out in a novel moving bed reactor with a two‐stage screw feeder. The effects of pyrolysis temperature (700–900 °C) and catalytic temperature (500–800 °C) on pyrolysis performance were investigated in product distribution gas composition and gas properties. The results showed that with the temperature increased pyrolysis gas yield in‐ creased but the yield of solid and liquid products decreased. With the increase in temperature the CO and H2 content increased significantly while the CO2 and CH4 decreased correspondingly. The calcined dolomite can remove the tar by 44% and increased syngas yield by 52.9%. With the increasing catalytic temperature the catalytic effect of calcined dolomite was also enhanced.
Pathways to Low-cost Clean Hydrogen Production with Gas Switching Reforming
Feb 2020
Publication
Gas switching reforming (GSR) is a promising technology for natural gas reforming with inherent CO2 capture. Like conventional steam methane reforming (SMR) GSR can be integrated with CO2 -gas shift and pressure swing adsorption units for pure hydrogen production. The resulting GSR-H2 process concept was techno-economically assessed in this study. Results showed that GSR-H2 can achieve 96% CO2 capture at a CO2 avoidance cost of 15 $/ton (including CO2 transport and storage). Most components of the GSR-H2 process are proven technologies but long-term oxygen carrier stability presents an important technical uncertainty that can adversely affect competitiveness when the material lifetime drops below one year. Relative to the SMR benchmark GSR-H2 replaces some fuel consumption with electricity consumption making it more suitable to regions with higher natural gas prices and lower electricity prices. Some minor alterations to the process configuration can adjust the balance between fuel and electricity consumption to match local market conditions. The most attractive commercialization pathway for the GSR-H2 technology is initial construction without CO2 capture followed by simple retrofitting for CO2 capture when CO2 taxes rise and CO2 transport and storage infrastructure becomes available. These features make the GSR-H2 technology robust to almost any future energy market scenario.
Secure, Affordable, Low Carbon: Gas in our Future Energy System
Feb 2020
Publication
Our gas network is one of the best developed in the world providing safe secure affordable energy to homes and businesses across the UK.<br/><br/>To meet the biggest energy challenge of our generation – making deep cuts to carbon emissions by 2050 – it needs to embrace new technology which builds on these strengths and delivers the integrated flexible network of the future. This briefing sets out how it is already doing that. Take a look at our Gas Futures Messages booklet attached.
Sustainable Hydrogen Production: A Role for Fusion
Apr 2007
Publication
This Meeting Report summarises the findings of a two-day workshop in April 2007 at the Culham Science Centre and Worcester College Oxford which explored the potential for large-scale Hydrogen production through methods other than electrolysis.<br/>Operating at the cusp of research and policy-making the UK Energy Research Centre's mission is to be the UK's pre-eminent centre of research and source of authoritative information and leadership on sustainable energy systems. The Centre takes a whole systems approach to energy research incorporating economics engineering and the physical environmental and social sciences while developing and maintaining the means to enable cohesive research in energy. A key supporting function of UKERC is the Meeting Place based in Oxford which aims to bring together members of the UK energy community and overseas experts from different disciplines to learn identify problems develop solutions and further the energy debate.
Charge Carrier Mapping for Z-scheme Photocatalytic Water-splitting Sheet via Categorization of Microscopic Time-resolved Image Sequences
Jun 2021
Publication
Photocatalytic water splitting system using particulate semiconductor materials is a promising strategy for converting solar energy into hydrogen and oxygen. In particular visible-light-driven ‘Z-scheme’ printable photocatalyst sheets are cost-effective and scalable. However little is known about the fundamental photophysical processes which are key to explaining and promoting the photoactivity. Here we applied the pattern-illumination time-resolved phase microscopy for a photocatalyst sheet composed of Mo-doped BiVO4 and Rh-doped SrTiO3 with indium tin oxide as the electron mediator to investigate photo-generated charge carrier dynamics. Using this method we successfully observed the position- and structure-dependent charge carrier behavior and visualized the active/inactive sites in the sheets under the light irradiation via the time sequence images and the clustering analysis. This combination methodology could provide the material/synthesis optimization methods for the maximum performance of the photocatalyst sheets.
Hydrogen Production from Natural Gas and Biomethane with Carbon Capture and Storage – A Techno-environmental Analysis
Mar 2020
Publication
This study presents an integrated techno-environmental assessment of hydrogen production from natural gas and biomethane combined with CO2 capture and storage (CCS). We have included steam methane reforming (SMR) and autothermal reforming (ATR) for syngas production. CO2 is captured from the syngas with a novel vacuum pressure swing adsorption (VPSA) process that combines hydrogen purification and CO2 separation in one cycle. As comparison we have included cases with conventional amine-based technology. We have extended standard attributional Life Cycle Assessment (LCA) following ISO standards with a detailed carbon balance of the biogas production process (via digestion) and its by-products. The results show that the life-cycle greenhouse gas (GHG) performance of the VPSA and amine-based CO2 capture technologies is very similar as a result of comparable energy consumption. The configuration with the highest plant-wide CO2 capture rate (almost 100% of produced CO2 captured) is autothermal reforming with a two-stage water-gas shift and VPSA CO2 capture – because the latter has an inherently high CO2 capture rate of 98% or more for the investigated syngas. Depending on the configuration the addition of CCS to natural gas reforming-based hydrogen production reduces its life-cycle Global Warming Potential by 45–85 percent while the other environmental life-cycle impacts slightly increase. This brings natural gas-based hydrogen on par with renewable electricity-based hydrogen regarding impacts on climate change. When biomethane is used instead of natural gas our study shows potential for net negative greenhouse gas emissions i.e. the net removal of CO2 over the life cycle of biowaste-based hydrogen production. In the special case where the biogas digestate is used as agricultural fertiliser and where a substantial amount of the carbon in the digestate remains in the soil the biowaste-based hydrogen reaches net-negative life cycle greenhouse gas emissions even without the application of CCS. Addition of CCS to biomethane-based hydrogen production leads to net-negative emissions in all investigated cases.
Pd Catalysts Supported on Bamboo-Like Nitrogen-Doped Carbon Nanotubes for Hydrogen Production
Mar 2021
Publication
Bamboo-like nitrogen-doped carbon nanotubes (N-CNTs) were used to synthesize supported palladium catalysts (0.2–2 wt.%) for hydrogen production via gas phase formic acid decomposition. The beneficial role of nitrogen centers of N-CNTs in the formation of active isolated palladium ions and dispersed palladium nanoparticles was demonstrated. It was shown that although the surface layers of N-CNTs are enriched with graphitic nitrogen palladium first interacts with accessible pyridinic centers of N-CNTs to form stable isolated palladium ions. The activity of Pd/N-CNTs catalysts is determined by the ionic capacity of N-CNTs and dispersion of metallic nanoparticles stabilized on the nitrogen centers. The maximum activity was observed for the 0.2% Pd/N-CNTs catalyst consisting of isolated palladium ions. A ten-fold increase in the concentration of supported palladium increased the contribution of metallic nanoparticles with a mean size of 1.3 nm and decreased the reaction rate by only a factor of 1.4.
Design of Experiment to Predict the Time Between Hydrogen Purges for an Air-breathing PEM Fuel Cell in Dead-end Mode in a Closed Environment
Feb 2021
Publication
Fuel cells are promising technologies for zero-emission energy conversion. They are used in several applications such as power plants cars and even submarines. Hydrogen supply is crucial for such systems and using Proton Exchange Membrane Fuel Cell in dead-end mode is a solution to save hydrogen. Since water and impurities accumulate inside the stack purging is necessary. However the importance of operating parameters is not well known for fuel cells working in closed environments. A Design of Experiment approach studying time between two purges and cell performance was conducted on an air-breathing stack in a closed environment. The most influential parameters on the time between two purges are the relative humidity and the current load. Convection in the closed environment can decrease the stability of the fuel cell. A linear model with interactions between these last three parameters was found to accurately describe the studied responses.
Study on Hydrogen from Renewable Resources in the EU
Feb 2016
Publication
Hydrogen can be produced from a broad range of renewable energy sources acting as a unique energy hub providing low or zero emission energy to all energy consuming sectors. Technically and efficiently producing hydrogen from renewable sources is a key enabler for these developments.<br/>Traditionally hydrogen has been produced from fossil sources by steam methane reforming of natural gas. At present the technology of choice to produce renewable ‘green’ hydrogen is water electrolysis using renewable electricity. The FCH JU has been supporting research and development of electrolyser technology and application projects aiming to increase the energy efficiency of electrolytic hydrogen production from renewable sources and to reduce costs.<br/>This study complements these activities by focusing on renewable hydrogen generation other than electrolysis. In this report these alternative hydrogen generation technologies are described characterized by their technical capabilities maturity and economic performance and assessed for their future potential.<br/>A methodology has been devised to first identify and structure a set of relevant green hydrogen pathways (eleven pathways depicted in the figure below) analyse them at a level of detail allowing a selection of those technologies which fit into and promise early commercialization in the framework of FCH 2 JU’s funding program.<br/>These originally proposed eleven pathways use solar thermal energy sunlight or biomass as major energy input.
Potential for Hydrogen Production from Sustainable Biomass with Carbon Capture and Storage
Jan 2022
Publication
Low-carbon hydrogen is an essential element in the transition to net-zero emissions by 2050. Hydrogen production from biomass is a promising bio-energy with carbon capture and storage (BECCS) scheme that could produce low-carbon hydrogen and generate the carbon dioxide removal (CDR) envisioned to be required to offset hard-to-abate emissions. Here we design a BECCS supply chain for hydrogen production from biomass with carbon capture and storage and quantify at high spatial resolution the technical potential for hydrogen production and CDR in Europe. We consider sustainable biomass feedstocks that have minimal impacts on food security and biodiversity namely agricultural residues and waste. We find that this BECCS supply chain can produce up to 12.5 Mtons of H2 per year (currently ~10 Mtons of H2 per year are used in Europe) and remove up to 133 Mtons CO2 per year from the atmosphere (or 3% of European total greenhouse gas emissions). We then perform a geospatial analysis to quantify transportation distances between where biomass feedstocks are located and potential hydrogen users and find that 20% of hydrogen potential is located within 25 km from hard-toelectrify industries. We conclude that BECCS supply chains for hydrogen production from biomass represent an overlooked near-term opportunity to generate carbon dioxide removal and low-carbon hydrogen.
Durability of Anion Exchange Membrane Water Electrolyzers
Apr 2021
Publication
Interest in the low-cost production of clean hydrogen is growing. Anion exchange membrane water electrolyzers (AEMWEs) are considered one of the most promising sustainable hydrogen production technologies because of their ability to split water using platinum group metal-free catalysts less expensive anode flow fields and bipolar plates. Critical to the realization of AEMWEs is understanding the durability-limiting factors that restrict the long-term use of these devices. This article presents both durability-limiting factors and mitigation strategies for AEMWEs under three operation modes i.e. pure water-fed (no liquid electrolyte) concentrated KOH-fed and 1 wt% K2CO3-fed operating at a differential pressure of 100 psi. We examine extended-term behaviors of AEMWEs at the single-cell level and connect their behavior with the electrochemical chemical and mechanical instability of single-cell components. Finally we discuss the pros and cons of AEMWEs under these operation modes and provide direction for long-lasting AEMWEs with highly efficient hydrogen production capabilities.
Future Cost and Performance of Water Electrolysis: An Expert Elicitation Study
Nov 2017
Publication
The need for energy storage to balance intermittent and inflexible electricity supply with demand is driving interest in conversion of renewable electricity via electrolysis into a storable gas. But high capital cost and uncertainty regarding future cost and performance improvements are barriers to investment in water electrolysis. Expert elicitations can support decision-making when data are sparse and their future development uncertain. Therefore this study presents expert views on future capital cost lifetime and efficiency for three electrolysis technologies: alkaline (AEC) proton exchange membrane (PEMEC) and solid oxide electrolysis cell (SOEC). Experts estimate that increased R&D funding can reduce capital costs by 0–24% while production scale-up alone has an impact of 17–30%. System lifetimes may converge at around 60000–90000 h and efficiency improvements will be negligible. In addition to innovations on the cell-level experts highlight improved production methods to automate manufacturing and produce higher quality components. Research into SOECs with lower electrode polarisation resistance or zero-gap AECs could undermine the projected dominance of PEMEC systems. This study thereby reduces barriers to investment in water electrolysis and shows how expert elicitations can help guide near-term investment policy and research efforts to support the development of electrolysis for low-carbon energy systems.
Synthesis and Characterisation of Platinum-cobalt-manganese Ternary Alloy Catalysts Supported on Carbon Nanofibers: An Alternative Catalyst for Hydrogen Evolution Reaction
Mar 2020
Publication
A systematic method for obtaining a novel electrode structure based on PtCoMn ternary alloy catalyst supported on graphitic carbon nanofibers (CNF) for hydrogen evolution reaction (HER) in acidic media is proposed. Ternary alloy nanoparticles (Co0.6Mn0.4 Pt) with a mean crystallite diameter under 10 nm were electrodeposited onto a graphitic support material using a two-step pulsed deposition technique. Initially a surface functionalisation of the carbon nanofibers is performed with the aid of oxygen plasma. Subsequently a short galvanostatic pulse electrodeposition technique is applied. It has been demonstrated that if pulsing current is employed compositionally controlled PtCoMn catalysts can be achieved. Variations of metal concentration ratios in the electrolyte and main deposition parameters such as current density and pulse shape led to electrodes with relevant catalytic activity towards HER. The samples were further characterised using several physico-chemical methods to reveal their morphology structure chemical and electrochemical properties. X-ray diffraction confirms the PtCoMn alloy formation on the graphitic support and energy dispersive X-ray spectroscopy highlights the presence of the three metallic components from the alloy structure. The preliminary tests regarding the electrocatalytic activity of the developed electrodes display promising results compared to commercial Pt/C catalysts. The PtCoMn/CNF electrode exhibits a decrease in hydrogen evolution overpotential of about 250 mV at 40 mA cm−2 in acidic solution (0.5 M H2SO4) when compared to similar platinum based electrodes (Pt/CNF) and a Tafel slope of around 120 mV dec−1 indicating that HER takes place under the Volmer-Heyrovsky mechanismm
Methodology for Efficient Parametrisation of Electrochemical PEMFC Model for Virtual Observers: Model Based Optimal Design of Experiments Supported by Parameter Sensitivity Analysis
Nov 2020
Publication
Determination of the optimal design of experiments that enables efficient parametrisation of fuel cell (FC) model with a minimum parametrisation data-set is one of the key prerequisites for minimizing costs and effort of the parametrisation procedure. To efficiently tackle this challenge the paper present an innovative methodology based on the electrochemical FC model parameter sensitivity analysis and application of D-optimal design plan. Relying on this consistent methodological basis the paper answers fundamental questions: a) on a minimum required data-set to optimally parametrise the FC model and b) on the impact of reduced space of operational points on identifiability of individual calibration parameters. Results reveal that application of D-optimal DoE enables enhancement of calibration parameters information resulting in up to order of magnitude lower relative standard errors on smaller data-sets. In addition it was shown that increased information and thus identifiability inherently leads to improved robustness of the FC electrochemical model.
Dual Z-scheme Charge Transfer in TiO2–Ag–Cu2O Composite for Enhanced Photocatalytic Hydrogen Generation
Apr 2015
Publication
Photocatalytic hydrogen generation is one of the most promising solutions to convert solar power into green chemical energy. In this work a multi-component TiO2–Ag–Cu2O composite was obtained through simple impregnation-calcination of Cu2O and subsequent photodeposition of Ag onto electrospun TiO2 nanotubes. The resulting TiO2–Ag–Cu2O photocatalyst exhibits excellent photocatalytic H2 evolution activity due to the synergetic effect of Ag and Cu2O on electrospun TiO2nanotubes. A dual Z-scheme charge transfer pathway for photocatalytic reactions over TiO2–Ag–Cu2O composite was proposed and discussed. This work provides a prototype for designing Z-scheme photocatalyst with Ag as an electron mediator.
Effect of Anion Exchange Ionomer Content on Electrode Performance in AEM Water Electrolysis
Aug 2020
Publication
Anion exchange membrane water electrolysis (AEMWE) has acquired substantial consideration as a cost-effective hydrogen production technology. The anion ionomer content in the catalyst layers during hydrogen and oxygen evolution reaction (HER and OER) is of ultimate significance. Herein an in-situ half-cell analysis with reference electrodes was carried out for simultaneous potential measurements and identification of the influence of the anion exchange ionomer (AEI) content on anode and cathode performance. The measured half-cell potentials proved the influence of AEI content on the catalytic activity of HER and OER which was supported by the rotating disk electrode (RDE) measurements. Cathode overpotential of Ni/C was not negligible and more affected by the AEI content than anode with the optimized AEI content of 10 wt% while NiO anode OER overpotential was independent of the AEI content. For the same AEI content PGM catalysts showed higher electroactivity than Ni-based catalysts for HER and OER and the cathode catalyst's intrinsic activity is of high importance in the AEM electrolysis operation. Post-mortem analysis by SEM mapping of both AEI and catalyst distributions on the electrode surface showed the effect of AEI loading on the catalyst morphology which could be related to the electrode performance.
A Comprehensive Review of Microbial Electrolysis Cells (MEC) Reactor Designs and Configurations for Sustainable Hydrogen Gas Production
Nov 2015
Publication
Hydrogen gas has tremendous potential as an environmentally acceptable energy carrier for vehicles. A cutting edge technology called a microbial electrolysis cell (MEC) can achieve sustainable and clean hydrogen production from a wide range of renewable biomass and wastewaters. Enhancing the hydrogen production rate and lowering the energy input are the main challenges of MEC technology. MEC reactor design is one of the crucial factors which directly influence on hydrogen and current production rate in MECs. The rector design is also a key factor to upscaling. Traditional MEC designs incorporated membranes but it was recently shown that membrane-free designs can lead to both high hydrogen recoveries and production rates. Since then multiple studies have developed reactors that operate without membranes. This review provides a brief overview of recent advances in research on scalable MEC reactor design and configurations.
Achievements of European Projects on Membrane Reactor for Hydrogen Production
May 2017
Publication
Membrane reactors for hydrogen production can increase both the hydrogen production efficiency at small scale and the electric efficiency in micro-cogeneration systems when coupled with Polymeric Electrolyte Membrane fuel cells. This paper discusses the achievements of three European projects (FERRET FluidCELL BIONICO) which investigate the application of the membrane reactor concept to hydrogen production and micro-cogeneration systems using both natural gas and biofuels (biogas and bio-ethanol) as feedstock. The membranes used to selectively separate hydrogen from the other reaction products (CH4 CO2 H2O etc.) are of asymmetric type with a thin layer of Pd alloy (<5 μm) and supported on a ceramic porous material to increase their mechanical stability. In FERRET the flexibility of the membrane reactor under diverse natural gas quality is validated. The reactor is integrated in a micro-CHP system and achieves a net electric efficiency of about 42% (8% points higher than the reference case). In FluidCELL the use of bio-ethanol as feedstock for micro-cogeneration Polymeric Electrolyte Membrane based system is investigated in off-grid applications and a net electric efficiency around 40% is obtained (6% higher than the reference case). Finally BIONICO investigates the hydrogen production from biogas. While BIONICO has just started FERRET and FluidCELL are in their third year and the two prototypes are close to be tested confirming the potentiality of membrane reactor technology at small scale.
A Perspective on Hydrogen Investment, Deployment and Cost Competitiveness
Feb 2021
Publication
Deployment and investments in hydrogen have accelerated rapidly in response to government commitments to deep decarbonisation establishing hydrogen as a key component in the energy transition.
To help guide regulators decision-makers and investors the Hydrogen Council collaborated with McKinsey & Company to release the report ‘Hydrogen Insights 2021: A Perspective on Hydrogen Investment Deployment and Cost Competitiveness’. The report offers a comprehensive perspective on market deployment around the world investment momentum as well as implications on cost competitiveness of hydrogen solutions.
The document can be downloaded from their website
To help guide regulators decision-makers and investors the Hydrogen Council collaborated with McKinsey & Company to release the report ‘Hydrogen Insights 2021: A Perspective on Hydrogen Investment Deployment and Cost Competitiveness’. The report offers a comprehensive perspective on market deployment around the world investment momentum as well as implications on cost competitiveness of hydrogen solutions.
The document can be downloaded from their website
Review of Renewable Energy-based Hydrogen Production Processes for Sustainable Energy Innovation
Dec 2019
Publication
In this review we primarily analyze the hydrogen production technologies based on water and biomass including the economic technological and environmental impacts of different types of hydrogen production technologies based on these materials and comprehensively compare them. Our analyses indicate that all renewable energy-based approaches for hydrogen production are more environmentally friendly than fossil-based hydrogen generation approaches. However the technical ease and economic efficiency of hydrogen production from renewable sources of energy needs to be further improved in order to be applied on a large scale. Compared with other renewable energy-based methods hydrogen production via biomass electrolysis has several advantages including the ease of directly using raw biomass. Furthermore its environmental impact is smaller than other approaches. Moreover using a noble metal catalyst-free anode for this approach can ensure a considerably low power consumption which makes it a promising candidate for clean and efficient hydrogen production in the future.
Towards an Understanding of Hydrogen Supply Chains: A Structured Literature Review Regarding Sustainability Evaluation
Oct 2021
Publication
Hydrogen technologies have received increased attention in research and development to foster the shift towards carbon-neutral energy systems. Depending on the specific production techniques transportation concepts and application areas hydrogen supply chains (HSCs) can be anything from part of the energy transition problem to part of the solution: Even more than battery-driven electric mobility hydrogen is a polyvalent technology and can be used in very different contexts with specific positive or negative sustainability impacts. Thus a detailed sustainability evaluation is crucial for decision making in the context of hydrogen technology and its diverse application fields. This article provides a comprehensive structured literature review in the context of HSCs along the triple bottom line dimensions of environmental economic and social sustainability analyzing a total of 288 research papers. As a result we identify research gaps mostly regarding social sustainability and the supply chain stages of hydrogen distribution and usage. We suggest further research to concentrate on these gaps thus strengthening our understanding of comprehensive sustainability evaluations for HSCs especially in social sustainability evaluation. In addition we provide an additional approach for discussion by adding literature review results from neighboring fields highlighting the joint challenges and insights regarding sustainability evaluation.
Modelling Decentralized Hydrogen Systems: Lessons Learned and Challenges from German Regions
Feb 2022
Publication
Green hydrogen produced by power‐to‐gas will play a major role in the defossilization of the energy system as it offers both carbon‐neutral chemical energy and the chance to provide flexibility. This paper provides an extensive analysis of hydrogen production in decentralized energy systems as well as possible operation modes (H2 generation or system flexibility). Modelling was realized for municipalities—the lowest administrative unit in Germany thus providing high spatial resolution—in the linear optimization framework OEMOF. The results allowed for a detailed regional analysis of the specific operating modes and were analyzed using full‐load hours share of used negative residual load installed capacity and levelized cost of hydrogen to derive the operation mode of power‐to‐gas to produce hydrogen. The results show that power‐to‐gas is mainly characterized by constant hydrogen production and rarely provides flexibility to the system. Main drivers of this dominant operation mode include future demand for hydrogen and the fact that high full‐load hours reduce hydrogen‐production costs. However changes in the regulatory market and technical framework could promote more flexibility and support possible use cases for the central technology to succeed in the energy transition.
Thoughts on the Prospects of Renewable Hydrogen
Oct 2020
Publication
In the last two years or so there has been increasing interest in hydrogen as an energy source in Australia and around the world. Notably this is not the first time that hydrogen has caught our collective interest. Most recently the 2000s saw a substantial investment in hydrogen research development and demonstration around the world. Prior to that the oil crises of the 1970s also stimulated significant investment in hydrogen and earlier still the literature on hydrogen was not lacking. And yet the hydrogen economy is still an idea only.<br/>So what if anything might be different this time?<br/>This is an important question that we all need to ask and for which the author can only give two potential answers. First our need to make dramatic reductions in greenhouse gas (GHG) emissions has become more pressing since these previous waves of interest. Second renewable energy is considerably more affordable now than it was before and it has consistently outperformed expectations in terms of cost reductions by even its strongest supporters.<br/>While this dramatic and ongoing reduction in the cost of renewables is very promising our need to achieve substantial GHG emission reductions is the crucial challenge. Moreover meeting this challenge needs to be achieved with as little adverse social and economic impact as possible.<br/>When considering what role hydrogen might play we should first think carefully about the massive scale and complexity of our global energy system and the typical prices of the major energy commodities. This provides insights into what opportunities hydrogen may have. Considering a temperate country with a small population like Australia we see that domestic natural gas and transport fuel markets are comparable to and even larger than the electricity market on an energy basis.
Techno-Economic Analysis of Hydrogen and Electricity Production by Biomass Calcium Looping Gasification
Feb 2022
Publication
Combined cycle biomass calcium looping gasification is proposed for a hydrogen and electricity production (CLGCC–H) system. The process simulation Aspen Plus is used to conduct techno-economic analysis of the CLGCC–H system. The appropriate detailed models are set up for the proposed system. Furthermore a dual fluidized bed is optimized for hydrogen production at 700 °C and 12 bar. For comparison calcium looping gasification with the combined cycle for electricity (CLGCC) is selected with the same parameters. The system exergy and energy efficiency of CLGCC–H reached as high as 60.79% and 64.75% while the CLGCC system had 51.22% and 54.19%. The IRR and payback period of the CLGCC–H system based on economic data are calculated as 17.43% and 7.35 years respectively. However the CLGCC system has an IRR of 11.45% and a payback period of 9.99 years respectively. The results show that the calcium looping gasification-based hydrogen and electricity coproduction system has a promising market prospect in the near future.
Fabrication of CdS/β-SiC/TiO2 Tri-composites That Exploit Hole- and Electron-transfer Processes for Photocatalytic Hydrogen Production Under Visible Light
Dec 2017
Publication
In this work CdS/SiC/TiO2 tri-composite photocatalysts that exploit electron- and hole-transfer processes were fabricated using an easy two-step method in the liquid phase. The photocatalyst with a 1:1:1 M ratio of CdS/SiC/TiO2 exhibited a rate of hydrogen evolution from an aqueous solution of sodium sulfite and sodium sulfide under visible light of 137 μmol h−1 g−1 which is 9.5 times that of pure CdS. β-SiC can act as a sink for the photogenerated holes because the valence band level of β-SiC is higher than the corresponding bands in CdS and TiO2. In addition the level of the conduction band of TiO2 is lower than those of CdS and β-SiC so TiO2 can act as the acceptor of the photogenerated electrons. Our results demonstrate that hole transfer and absorption in the visible light region lead to an effective hydrogen-production scheme.
Methane Pyrolysis in a Molten Gallium Bubble Column Reactor for Sustainable Hydrogen Production: Proof of Concept & Techno-economic Assessment
Dec 2020
Publication
Nowadays nearly 50% of the hydrogen produced worldwide comes from Steam Methane Reforming (SMR) at an environmental burden of 10.5 tCO2 eq/tH2 accelerating the consequences of global warming. One way to produce clean hydrogen is via methane pyrolysis using melts of metals and salts. Compared to SMR significant less CO2 is produced due to conversion of methane into hydrogen and carbon making this route more sustainable to generate hydrogen. Hydrogen is produced with high purity and solid carbon is segregated and deposited on the molten bath. Carbon may be sold as valuable co-product making industrial scale promising. In this work methane pyrolysis was performed in a quartz bubble column using molten gallium as heat transfer agent and catalyst. A maximum conversion of 91% was achieved at 1119 °C and ambient pressure with a residence time of the bubbles in the liquid of 0.5 s. Based on in-depth analysis of the carbon it can be characterized as carbon black. Techno-economic and sensitivity analyses of the industrial concept were done for different scenarios. The results showed that if co-product carbon is saleable and a CO2 tax of 50 euro per tonne is imposed to the processes the molten metal technology can be competitive with SMR.
MELCOR Analysis of a SPARC Experiment for Spray-PAR Interaction During a Hydrogen Release
Oct 2020
Publication
A series of experiments were performed in the SPARC (spray-aerosol-recombiner-combustion) test facility to simulate a hydrogen mitigation system with the actuation of a PAR (passive auto-catalytic re-combiner) and spray system. In this study the SPARC-SPRAY-PAR (SSP1) experiment is chosen to benchmark the MELCOR (a lumped-parameter code for severe accident analysis) predictions against test data. For this purpose firstly we prepared the base input model of the SPARC test vessel and tested it by a simple verification problem with well-defined boundary conditions. The implementation of a currently used PAR correlation in MELCOR is shown to be appropriate for the simulation of a PAR actuation experiment. In an SSP1 experiment the PAR is reacting with hydrogen and the spray actuation starts as soon as hydrogen injection is complete. The MELCOR simulation well predicts the pressure behavior and the gas flow affected by operating both a PAR and spray system. However the local hydrogen concentration measurement near the inlet nozzle is much higher than the volume average-value by MELCOR since high jet flow from the nozzle is dispersed in the corresponding cell volume. The experimental reproduction of the phenomena we expect or conversely the identification of phenomena we do not understand will continue to support the verification of analytical models using experimental data and to analyze the impact of spray on PAR operations in severe accident conditions.
The ‘Green’ Ni-UGSO Catalyst for Hydrogen Production under Various Reforming Regimes
Jun 2021
Publication
A new spinelized Ni catalyst (Ni-UGSO) using Ni(NO3)2·6H2O as the Ni precursor was prepared according to a less material intensive protocol. The support of this catalyst is a negative-value mining residue UpGraded Slag Oxide (UGSO) produced from a TiO2 slag production unit. Applied to dry reforming of methane (DRM) at atmospheric pressure T = 810 °C space velocity of 3400 mL/(h·g) and molar CO2/CH4 = 1.2 Ni-UGSO gives a stable over 168 h time-on-stream methane conversion of 92%. In this DRM reaction optimization study: (1) the best performance is obtained with the 10–13 wt% Ni load; (2) the Ni-UGSO catalysts obtained from two different batches of UGSO demonstrated equivalent performances despite their slight differences in composition; (3) the sulfur-poisoning resistance study shows that at up to 5.5 ppm no Ni-UGSO deactivation is observed. In steam reforming of methane (SRM) Ni-UGSO was tested at 900 °C and a molar ratio of H2O/CH4 = 1.7. In this experimental range CH4 conversion rapidly reached 98% and remained stable over 168 h time-on-stream (TOS). The same stability is observed for H2 and CO yields at around 92% and 91% respectively while H2/CO was close to 3. In mixed (dry and steam) methane reforming using a ratio of H2O/CH4 = 0.15 and CO2/CH4 = 0.97 for 74 h and three reaction temperature levels (828 °C 847 °C and 896 °C) CH4 conversion remains stable; 80% at 828 °C (26 h) 85% at 847 °C (24 h) and 95% at 896 °C (24 h). All gaseous streams have been analyzed by gas chromatography. Both fresh and used catalysts are analyzed by scanning electron microscopy-electron dispersive X-ray spectroscopy (SEM-EDXS) X-ray diffraction (XRD) and thermogravimetric analysis (TGA) coupled with mass spectroscopy (MS) and BET Specific surface. In the reducing environment of reforming such catalytic activity is mainly attributed to (a) alloys such as FeNi FeNi3 and Fe3Ni2 (reduction of NiFe2O4 FeNiAlO4) and (b) to the solid solution NiO-MgO. The latter is characterized by a molecular distribution of the catalytically active Ni phase while offering an environment that prevents C deposition due to its alkalinity.
A Review of the CFD Modeling of Hydrogen Production in Catalytic Steam Reforming Reactors
Dec 2022
Publication
Global demand for alternative renewable energy sources is increasing due to the consumption of fossil fuels and the increase in greenhouse gas emissions. Hydrogen (H2 ) from biomass gasification is a green energy segment among the alternative options as it is environmentally friendly renewable and sustainable. Accordingly researchers focus on conducting experiments and modeling the reforming reactions in conventional and membrane reactors. The construction of computational fluid dynamics (CFD) models is an essential tool used by researchers to study the performance of reforming and membrane reactors for hydrogen production and the effect of operating parameters on the methane stream improving processes for reforming untreated biogas in a catalyst-fixed bed and membrane reactors. This review article aims to provide a good CFD model overview of recent progress in catalyzing hydrogen production through various reactors sustainable steam reforming systems and carbon dioxide utilization. This article discusses some of the issues challenges and conceivable arrangements to aid the efficient generation of hydrogen from steam reforming catalytic reactions and membrane reactors of bioproducts and fossil fuels.
Simulation of a Multi-Functional Energy System for Cogeneration of Steam, Power and Hydrogen in a Coke Making Plant
Mar 2013
Publication
In this paper a multifunctional energy system (MES) is proposed for recovering energy from the extra of coke oven gas (COG) which is usually flared or vented out as a waste stream in coke making plants. The proposed system consists of a pressure swing adsorption (PSA) unit for extracting some of the hydrogen from COG a gas turbine for producing heat and power from PSA offgas and a heat recovery steam generator (HRSG) for generating the steam required by the plant's processes. o assess the performance of the system practically simulations are carried out on the basis of the design and operational conditions of Zarand Coke Making Plant in Iran. The results indicate that by utilizing about 4.39 tons of COG per hour 6.5 MW of net electric power can be approximately produced by the gas turbine which can supply the coke making plant's total electrical power demand. Furthermore through recovering heat from gas turbine's exhaust close to 57% of the plant's steam demand can be supplied by the HRSG unit. It is also found that around 350 kilograms per hour of nearly pure hydrogen (99.9% purity) at 200 bar can be produced by the PSA unit. According to the sensitivity analysis results if the hydrogen content of the coke oven gas decreases by about 10% the gross power output of the gas turbine also declines by around 5.2% due to the reduction of LHV of the PSA offgas. Moreover economic evaluation of the system shows that the payback period of the investment which is estimated at 36.1 M$ is about 5.5 years. The net present value (NPV) and internal rate of return on investment (ROI) are calculated to be 17.6% and 43.3 M$ respectively.
Operational Challenges for Low and High Temperature Electrolyzers Exploiting Curtailed Wind Energy for Hydrogen Production
Jan 2021
Publication
Understanding the system performance of different electrolyzers could aid potential investors achieve maximum return on their investment. To realize this system response characteristics to 4 different summarized data sets of curtailed renewable energy is obtained from the Irish network and was investigated using models of both a Low Temperature Electrolyzer (LTE) and a High Temperature Electrolyzer (HTE). The results indicate that statistical parameters intrinsic to the method of data extraction along with the thermal response time of the electrolyzers influence the hydrogen output. A maximum hydrogen production of 5.97 kTonne/year is generated by a 0.5 MW HTE when the electrical current is sent as a yearly average. Additionally the high thermal response time in a HTE causes a maximum change in the overall flowrate of 65.7% between the 4 scenarios when compared to 7.7% in the LTE. This evaluation of electrolyzer performance will aid investors in determining scenario specific application of P2G for maximizing hydrogen production.
Energy Technology Perspectives 2020- Special Report on Carbon Capture Utilisation and Storage
Sep 2020
Publication
Energy Technology Perspectives 2020 is a major new IEA publication focused on the technology needs and opportunities for reaching international climate and sustainable energy goals. This flagship report offers vital analysis and advice on the clean energy technologies the world needs to meet net-zero emissions objectives.
The report’s comprehensive analysis maps out the technologies needed to tackle emissions in all parts of the energy sector including areas where technology progress is still lacking such as long-distance transport and heavy industries. It shows the amount of emissions reductions that are required from electrification hydrogen bioenergy and carbon capture utilisation and storage. It also provides an assessment of emissions from existing infrastructure and what can be done to address them.
Link to Document on IEA website
The report’s comprehensive analysis maps out the technologies needed to tackle emissions in all parts of the energy sector including areas where technology progress is still lacking such as long-distance transport and heavy industries. It shows the amount of emissions reductions that are required from electrification hydrogen bioenergy and carbon capture utilisation and storage. It also provides an assessment of emissions from existing infrastructure and what can be done to address them.
Link to Document on IEA website
Tracking the Evolution of a Single Composite Particle During Redox Cycling for Application in H2 Production
Mar 2020
Publication
Composite materials consisting of metal and metal oxide phases are being researched intensively for application in various energy conversion and storage technologies. In these applications composites are often expected to operate under redox conditions at elevated temperature. The understanding of the dynamics of composite phase and morphology evolution during redox cycling is still very limited yet critical to maximising performance and increasing durability. Here we track the microstructural evolution of a single composite particle over 200 redox cycles for hydrogen production by chemical looping using multi-length scale X-ray computed tomography. We show that redox cycling triggers a centrifugal redispersion of the metal phase and a centripetal clustering of porosity both seemingly driven by the asymmetric nature of oxygen exchange in composites. We show that initially the particle develops a large amount of internal porosity which boosts activity but on the long term this facilitates structural and compositional reorganisation and eventually degradation. We also correlate the microstructural data with phase and activity analysis to identify structure-property correlations which not only provide valuable insight into the evolution of composite materials under redox conditions but also for the design of new composite materials with enhanced durability.
A Methodology for Assessing the Sustainability of Hydrogen Production from Solid Fuels
May 2010
Publication
A methodology for assessing the sustainability of hydrogen production using solid fuels is introduced in which three sustainability dimensions (ecological sociological and technological) are considered along with ten indicators for each dimension. Values for each indicator are assigned on a 10-point scale based on a high of 1 and a low of 0 depending on the characteristic of the criteria associated with each element or process utilizing data reported in the literature. An illustrative example is presented to compare two solid fuels for hydrogen production: coal and biomass. The results suggest that qualitative sustainability indicators can be reasonably defined based on evaluations of system feasibility and that adequate flexibility and comprehensiveness is provided through the use of ten indicators for each of the dimensions for every process or element involved in hydrogen production using solid fuels. Also the assessment index values suggest that biomasses have better sustainability than coals and that it may be advantageous to use coals in combination with biomass to increase their ecological and social sustainability. The sustainability assessment methodology can be made increasingly quantitative and is likely extendable to other energy systems but additional research and development is needed to lead to a more fully developed approach.
Removing the Bottleneck on Wind Power Potential to Create Liquid Fuels from Locally Available Biomass
Jun 2021
Publication
In order to reduce global greenhouse gas emissions renewable energy technologies such as wind power and solar photovoltaic power systems have recently become more widespread. However Japan as a nation faces high reliance on imported fossil fuels for electricity generation despite having great potential for further renewable energy development. The focus of this study examines untapped geographical locations in Japan’s northern most prefecture Hokkaido that possess large wind power potential. The possibility of exploiting this potential for the purpose of producing green hydrogen is explored. In particular its integration with a year-round conversion of Kraft lignin into bio-oil from nearby paper pulp mills through a near critical water depolymerization process is examined. The proposed bio-oil and aromatic chemical production as well as the process’ economics are calculated based upon the total available Kraft lignin in Hokkaido including the magnitude of wind power capacity that would be required for producing the necessary hydrogen for such a large-scale process. Green hydrogen integration with other processes in Japan and in other regions is also discussed. Finally the potential benefits and challenges are outlined from an energy policy point-of-view.
Efficient Hydrogen Production with CO2 Capture Using Gas Switching Reforming
Jul 2019
Publication
Hydrogen is a promising carbon-neutral energy carrier for a future decarbonized energy sector. This work presents process simulation studies of the gas switching reforming (GSR) process for hydrogen production with integrated CO2 capture (GSR-H2 process) at a minimal energy penalty. Like the conventional steam methane reforming (SMR) process GSR combusts the off-gas fuel from the pressure swing adsorption unit to supply heat to the endothermic reforming reactions. However GSR completes this combustion using the chemical looping combustion mechanism to achieve fuel combustion with CO2 separation. For this reason the GSR-H2 plant incurred an energy penalty of only 3.8 %-points relative to the conventional SMR process with 96% CO2 capture. Further studies showed that the efficiency penalty is reduced to 0.3 %-points by including additional thermal mass in the reactor to maintain a higher reforming temperature thereby facilitating a lower steam to carbon ratio. GSR reactors are standalone bubbling fluidized beds that will be relatively easy to scale up and operate under pressurized conditions and the rest of the process layout uses commercially available technologies. The ability to produce clean hydrogen with no energy penalty combined with this inherent scalability makes the GSR-H2 plant a promising candidate for further research.
Ordered Clustering of Single Atomic Te Vacancies in Atomically Thin PtTe2 Promotes Hydrogen Evolution Catalysis
Apr 2021
Publication
Exposing and stabilizing undercoordinated platinum (Pt) sites and therefore optimizing their adsorption to reactive intermediates offers a desirable strategy to develop highly efficient Pt-based electrocatalysts. However preparation of atomically controllable Pt-based model catalysts to understand the correlation between electronic structure adsorption energy and catalytic properties of atomic Pt sites is still challenging. Herein we report the atomically thin two-dimensional PtTe2 nanosheets with well-dispersed single atomic Te vacancies (Te-SAVs) and atomically well-defined undercoordinated Pt sites as a model electrocatalyst. A controlled thermal treatment drives the migration of the Te-SAVs to form thermodynamically stabilized ordered Te-SAV clusters which decreases both the density of states of undercoordinated Pt sites around the Fermi level and the interacting orbital volume of Pt sites. As a result the binding strength of atomically defined Pt active sites to H intermediates is effectively reduced which renders PtTe2 nanosheets highly active and stable in hydrogen evolution reaction.
Debunking the Myths of Hydrogen Production and Water Consumption
Dec 2020
Publication
In our factsheet where we debunk 3 myths around hydrogen production and water consumption: electrolysis uses vast amounts of water; electrolysis uses freshwater resources only and electrolysis is bound to create water stress in water-scarce regions.
A Review on Recent Advances in Hydrogen Energy, Fuel Cell, Biofuel and Fuel Refining via Ultrasound Process Intensification
Mar 2021
Publication
Hydrogen energy is one of the most suitable green substitutes for harmful fossil fuels and has been investigated widely. This review extensively compiles and compares various methodologies used in the production storage and usage of hydrogen. Sonochemistry is an emerging synthesis process and intensification technique adapted for the synthesis of novel materials. It manifests acoustic cavitation phenomena caused by ultrasound where higher rates of reactions occur locally. The review discusses the effectiveness of sonochemical routes in developing fuel cell catalysts fuel refining biofuel production chemical processes for hydrogen production and the physical chemical and electrochemical hydrogen storage techniques. The operational parameters and environmental conditions used during ultrasonication also influence the production rates which have been elucidated in detail. Hence this review's major focus addresses sonochemical methods that can contribute to the technical challenges involved in hydrogen usage for energy.
Enhancing Energy Recovery in Form of Biogas, from Vegetable and Fruit Wholesale Markets By-Products and Wastes, with Pretreatments
Jun 2021
Publication
Residues and by-products from vegetables and fruit wholesale markets are suitable for recovery in the form of energy through anaerobic digestion allowing waste recovery and introducing them into the circular economy. This suitability is due to their composition structural characteristics and to the biogas generation process which is stable and without inhibition. However it has been observed that the proportion of methane and the level of degradation of the substrate is low. It is decided to study whether the effect of pretreatments on the substrate is beneficial. Freezing ultrafreezing and lyophilization pretreatments are studied. A characterization of the substrates has been performed the route of action of pretreatment determined and the digestion process studied to calculate the generation of biogas methane hydrogen and the proportions among these. Also a complete analysis of the process has been performed by processing the data with mathematical and statistical methods to obtain disintegration constants and levels of degradation. It has been observed that the three pretreatments have positive effects when increasing the solubility of the substrate increasing porosity and improving the accessibility of microorganisms to the substrate. Generation of gases are greatly increased reaching a methane enrichment of 59.751%. Freezing seems to be the best pretreatment as it increases the biodegradation level the speed of the process and the disintegration constant by 306%.
Analysis of Photon-driven Solar-to-hydrogen Production Methods in the Netherlands
Oct 2021
Publication
Hydrogen is deemed necessary for the realization of a sustainable society especially when renewable energy is used to generate hydrogen. As most of the photon-driven hydrogen production methods are not commercially available yet this study has investigated the techno economic and overall performance of four different solar-to hydrogen methods and photovoltaics-based electrolysis methods in the Netherlands. It was found that the photovoltaics-based electrolysis is the cheapest option with production cost of 9.31 $/kgH2. Production cost based on photo-catalytic water splitting direct bio-photolysis and photoelectrochemical water splitting are found to be 18.32 $/kgH2 18.45 $/kgH2 and 18.98 $/kgH2 respectively. These costs are expected to drop significantly in the future. Direct bio-photolysis (potential cost of 3.10 $/kgH2) and photo-catalytic water splitting (3.12 $/kgH2) may become cheaper than photovoltaics-based electrolysis. Based on preferences of three fictional technology investors i.e. a short-term a green and a visionary investor the overall performance of these methods are determined. Photovoltaics-based electrolysis is the most ideal option with photoelectrochemical water splitting a complementary option. While photovoltaics-based electrolysis has an advantage on the short-term because it is a non-integrated energy system on the long-term this might lead to relatively higher cost and performance limitations. Photochemical water splitting are integrated energy systems and have an advantage on the long-term because they need a relatively low theoretical overpotential and benefit from increasing temperatures. Both methods show performance improvements by the use of quantum dots. Bio-photolysis can be self-sustaining and can use wastewater to produce hydrogen but sudden temperature changes could lead to performance decrease.
A Techno-Economic Analysis of Solar Hydrogen Production by Electrolysis in the North of Chile and the Case of Exportation from Atacama Desert to Japan
Aug 2020
Publication
H2 production from solar electricity in the region of the Atacama Desert – Chile – has been identified as strategical for global hydrogen exportation. In this study the full supply chain of solar hydrogen has been investigated for 2018 and projected to scenarios for 2025-2030. Multi-year hourly electrical profiles data have been used from real operating PV plants and simulated Concentrated Solar Power “CSP” plants with Thermal Energy Storage “TES” as well as commercial electricity Power Purchase Agreement “PPA” prices reported in the Chilean electricity market were considered. The Levelized Cost of Hydrogen “LCOH” of each production pathway is calculated by a case-sensitive techno-economic MATLAB/Simulink model for utility scale (multi-MW) alkaline and PEM electrolyser technologies. Successively different distribution storage and transportation configurations are evaluated based on the 2025 Japanese case study according to the declared H2 demand. Transport in the form of liquefied hydrogen (LH2) and via ammonia (NH3) carrier is compared from the port of Antofagasta CL to the port of Osaka JP.
Asymmetric Solvation of the Zinc Dimer Cation Revealed by Infrared Multiple Photon Dissociation Spectroscopy of Zn2+(H2O)n (n = 1–20)
Jun 2021
Publication
Investigating metal-ion solvation—in particular the fundamental binding interactions—enhances the understanding of many processes including hydrogen production via catalysis at metal centers and metal corrosion. Infrared spectra of the hydrated zinc dimer (Zn2+(H2O)n; n = 1–20) were measured in the O–H stretching region using infrared multiple photon dissociation (IRMPD) spectroscopy. These spectra were then compared with those calculated by using density functional theory. For all cluster sizes calculated structures adopting asymmetric solvation to one Zn atom in the dimer were found to lie lower in energy than structures adopting symmetric solvation to both Zn atoms. Combining experiment and theory the spectra show that water molecules preferentially bind to one Zn atom adopting water binding motifs similar to the Zn+(H2O)n complexes studied previously. A lower coordination number of 2 was observed for Zn2+(H2O)3 evident from the highly red-shifted band in the hydrogen bonding region. Photodissociation leading to loss of a neutral Zn atom was observed only for n = 3 attributed to a particularly low calculated Zn binding energy for this cluster size.
Hydrogen Production from Instant Noodle Wastewater by Organic Electrocatalyst Coated on PVC Surface
Mar 2020
Publication
The potential of electron-donating capability in methoxy groups of antioxidant containing protein (ACAP) as organic catalyst is restricted by its low isoelectric point. The goal of this study is to construct endure ACAP based metal-free organic catalyst for hydrogen production from electrolysis of noodle wastewater. The ACAP was coated thermomechanically on PVC sheet and its performance was tested during electrolysis of noodle wastewater. The morphological analysis phase analysis and elemental analysis of coated materials have shown a simultaneous pattern with electrolysis performances. The use of graphite flake to cover turmeric ACAP obstructs the electron to attack directly the positive charge of ACAP so that the electrocatalytic endurance increases while maintaining the hydrogen production rate. The combination of phenolic and enzymatic ACAPs is found to have the slowest reaction rate and lowest hydrogen production. The phenolic compound inhibits the enzymatic reaction.
Black TiO2 for Solar Hydrogen Conversion
Feb 2017
Publication
Titanium dioxide (TiO2 ) has been widely investigated for photocatalytic H2 evolution and photoelectrochemical (PEC) water splitting since 1972. However its wide bandgap (3.0–3.2 eV) limits the optical absorption of TiO2 for sufficient utilization of solar energy. Blackening TiO2 has been proposed as an effective strategy to enhance its solar absorption and thus the photocatalytic and PEC activities and aroused widespread research interest. In this article we reviewed the recent progress of black TiO2 for photocatalytic H2 evolution and PEC water splitting along with detailed introduction to its unique structural features optical property charge carrier transfer property and related theoretical calculations. As summarized in this review article black TiO2 could be a promising candidate for photoelectrocatalytic hydrogen generation via water splitting and continuous efforts are deserved for improving its solar hydrogen efficiency.
The Role of Critical Minerals in Clean Energy Transitions
May 2021
Publication
Minerals are essential components in many of today’s rapidly growing clean energy technologies – from wind turbines and electricity networks to electric vehicles. Demand for these minerals will grow quickly as clean energy transitions gather pace. This new World Energy Outlook Special Report provides the most comprehensive analysis to date of the complex links between these minerals and the prospects for a secure rapid transformation of the energy sector.
Alongside a wealth of detail on mineral demand prospects under different technology and policy assumptions it examines whether today’s mineral investments can meet the needs of a swiftly changing energy sector. It considers the task ahead to promote responsible and sustainable development of mineral resources and offers vital insights for policy makers including six key IEA recommendations for a new comprehensive approach to mineral security."
Link to International Energy Agency website
Alongside a wealth of detail on mineral demand prospects under different technology and policy assumptions it examines whether today’s mineral investments can meet the needs of a swiftly changing energy sector. It considers the task ahead to promote responsible and sustainable development of mineral resources and offers vital insights for policy makers including six key IEA recommendations for a new comprehensive approach to mineral security."
Link to International Energy Agency website
Hydrogen Production by Steam Reforming of DME in a Large Scale CFB Reactor. Part I: Computational Model and Predictions
Oct 2015
Publication
This study presents a computational fluid dynamic (CFD) study of Dimethyl Ether steam reforming (DME-SR) in a large scale Circulating Fluidized Bed (CFB) reactor. The CFD model is based on Eulerian–Eulerian dispersed flow and solved using commercial software (ANSYS FLUENT). The DME-SR reactions scheme and kinetics in the presence of a bifunctional catalyst of CuO/ZnO/Al2O3+ZSM-5 were incorporated in the model using in-house developed user-defined function. The model was validated by comparing the predictions with experimental data from the literature. The results revealed for the first time detailed CFB reactor hydrodynamics gas residence time temperature distribution and product gas composition at a selected operating condition of 300 °C and steam to DME mass ratio of 3 (molar ratio of 7.62). The spatial variation in the gas species concentrations suggests the existence of three distinct reaction zones but limited temperature variations. The DME conversion and hydrogen yield were found to be 87% and 59% respectively resulting in a product gas consisting of 72 mol% hydrogen. In part II of this study the model presented here will be used to optimize the reactor design and study the effect of operating conditions on the reactor performance and products.
The BioSCWG Project: Understanding the Trade-Offs in the Process and Thermal Design of Hydrogen and Synthetic Natural Gas Production
Oct 2016
Publication
This article presents a summary of the main findings from a collaborative research project between Aalto University in Finland and partner universities. A comparative process synthesis modelling and thermal assessment was conducted for the production of Bio-synthetic natural gas (SNG) and hydrogen from supercritical water refining of a lipid extracted algae feedstock integrated with onsite heat and power generation. The developed reactor models for product gas composition yield and thermal demand were validated and showed conformity with reported experimental results and the balance of plant units were designed based on established technologies or state-of-the-art pilot operations. The poly-generative cases illustrated the thermo-chemical constraints and design trade-offs presented by key process parameters such as plant organic throughput supercritical water refining temperature nature of desirable coproducts downstream indirect production and heat recovery scenarios. The evaluated cases favoring hydrogen production at 5 wt. % solid content and 600 ◦C conversion temperature allowed higher gross syngas and CHP production. However mainly due to the higher utility demands the net syngas production remained lower compared to the cases favoring BioSNG production. The latter case at 450 ◦C reactor temperature 18 wt. % solid content and presence of downstream indirect production recorded 66.5% 66.2% and 57.2% energetic fuel-equivalent and exergetic efficiencies respectively
Production of Hydrogen by Chemical Looping Reforming of Methane and Biogas using a Reactive and Durable Cu-based Oxygen Carrier
Apr 2022
Publication
The objective of this work was to assess the suitability of a synthetic Cu-based oxygen carrier in a continuous pilot plant for the production of blue and green hydrogen through the autothermal Chemical Looping Reforming (CLRa). In CLRa methane is converted to a H2 + CO mixture through partial oxidation and reforming reactions in the fuel reactor. The degree of the partial oxidation of methane was defined by controlling the oxygen flow in the air reactor. Steam was used as reforming gas in natural gas to produce blue H2 but the existing CO2 in biogas was the reforming gas to produce green H2. Operating at 950 ◦C in the fuel and air reactors CH4 conversion and H2 yield parameters were 96 % and 2.60 mol of H2 per mole of CH4 respectively. These experimental results were close to the theoretical values that could be achieved in the CLRa process. Furthermore the physico-chemical characterization of the samples extracted from the pilot plant throughout the experimental campaign revealed that the Cu-based oxygen carrier maintained its mechanical integrity and chemical stability under harsh operating conditions. Therefore it can be concluded that Cu-based oxygen carriers can be considered a promising alternative to Ni-based materials for the production of blue and green hydrogen through the CLRa process.
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