Production & Supply Chain

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.

Hydrogen is known to be the carbon-neutral alternative energy carrier with the highest energy density. Currently more than 95% of hydrogen production technologies rely on fossil fuels resulting in greenhouse gas emissions. Water electrolysis is one of the most widely used technologies for hydrogen generation. Nuclear power a renewable energy source can provide the heat needed for the process of steam electrolysis for clean hydrogen production. This review paper analyses the recent progress in hydrogen generation via high-temperature steam electrolysis through solid oxide electrolysis cells using nuclear thermal energy. Protons and oxygen-ions conducting solid oxide electrolysis processes are discussed in this paper. The scope of this review report covers a broad range including the recent advances in material development for each component (i.e. hydrogen electrode oxygen electrode electrolyte interconnect and sealant) degradation mechanisms and countermeasures to mitigate them.

The present review focuses on the current progress on harnessing the potential of hydrogen production by Methane Steam Reforming (MSR). First based on the prominent literature in last few years the overall research efforts of hydrogen production using different feed stocks like ethanol ammonia glycerol methanol and methane is presented. The presented data is based on reactor type reactor operating conditions catalyst used and yield of hydrogen to provide a general overview. Then the most widely used process [steam methane reforming (SMR)/ methane steam reforming (MSR)] are discussed. Major advanced reactors the membrane reactors Sorption Enhanced methane steam reforming reactors and micro-reactors are evaluated. The evaluation has been done based on parameters like residence time surface area scale-up coke formation conversion space velocity and yield of hydrogen. The kinetic models available in recently published literature for each of these reactors have been presented with the rate constants and other parameters. The mechanism of coke formation and the rate expressions for the same have also been presented. While membrane reactors and sorption enhanced reactors have lot of advantages in terms of process intensification scale-up to industrial scale is still a challenge due to factors like membrane stability and fouling (in membrane reactors) decrease in yield with increasing WHSV (in case of Sorption Enhanced Reactors). Micro-reactors pose a higher potential in terms of higher yield and very low residence time in seconds though the volumes might be substantially lower than present industrial scale conventional reactors.

Although polymer electrolyte water electrolyzers (PEWEs) have been used in small-scale (kW to tens of kW range) applications for several decades PEWE technology for hydrogen production in energy applications (power-to-gas power-to-fuel etc.) requires significant improvements in the technology to address the challenges associated with cost performance and durability. Systems with power of hundreds of kW or even MWs corresponding to hydrogen production rates of around 10 to 20 kg/h have started to appear in the past 5 years. The thin (∼0.2 mm) polymer electrolyte in the PEWE with low ohmic resistance compared to the alkaline cell with liquid electrolyte allows operation at high current densities of 1–3 A/cm2 and high differential pressure. This article after an introductory overview of the operating principles of PEWE and state-of-the-art discusses the state of understanding of key phenomena determining and limiting performance durability and commercial readiness identifies important ‘gaps’ in understanding and essential development needs to bring PEWE science & engineering forward to prosper in the energy market as one of its future backbone technologies. For this to be successful science engineering and process development as well as business and market development need to go hand in hand.

Hydrogen is an energy carrier with potential applications in decarbonizing difficult-to-electrify energy and industrial systems. The environmental profile of hydrogen varies substantially with its inputs. Water consumption is a particular issue of interest as decisions are made about capital and other investments that will affect the scale and scope of hydrogen use. This study focuses on electrolytic hydrogen due to its path to greenhouse gas neutrality and irreducible water demand (though other pathways might be more water intensive). Specifically it evaluates life cycle consumptive freshwater intensity of electrolytic hydrogen in the United States at volumes associated with 12 scenarios for a deeply decarbonized 2050 US energy system from two modeling efforts for which both electricity fuel mix and electrolytic hydrogen production were projected (America’s Zero Carbon Action Plan and Net Zero America) in addition to volumes for a stylized energy storage project (500 MW hydrogen-fired turbine). Freshwater requirements for hydrogen could be large. Under a central estimate for 2050 US electrolytic hydrogen production electrolytic freshwater demand for process and feedstock inputs alone (i.e. excluding water for electricity) would be about 7.5% of total 2014 US freshwater consumption for energy (1 billion cubic meters/year 109 m3 /y; [0.2% 15%] across scenarios for 2050 electrolytic hydrogen production of [0.3 18] exajoules EJ). Including water associated with production of input electricity doubles this central estimate to 15% (2 × 109 m3 /y; [1% 23%] across scenarios). Turbines using electrolytic hydrogen are estimated to be about as freshwater intensive as a coal or nuclear plant assuming decarbonized low-water electricity inputs. Although a decarbonized energy system is projected to require less water for resource capture and electricity conversion than the current fossil-dominated energy system additional conversion processes supporting decarbonization like electrolysis could offset water savings.

The reliability of renewable hydrogen supply for off-take applications is critical to the future sustainable energy economy. Integrated water electrolysis can be deployed at distributed municipal wastewater treatment plants (WWTP) creating opportunity for reduction in carbon emissions through direct and indirect use of the electrolysis output. A novel energy shifting process where the co-produced oxygen is compressed and stored to enhance the utilisation of intermittent renewable electricity is analysed. The hydrogen produced can be used in local fuel cell electric buses to replace incumbent diesel buses for public transport. However quantifying the extent of carbon emission reduction of this conceptual integrated system is key. In this study the integration of hydrogen production at a case study WWTP of 26000 EP capacity and using the hydrogen in buses was compared with two conventional systems: the base case of a WWTP with grid electricity consumption offset by solar PV and the community’s independent use of diesel buses for transport and the non-integrated configuration with hydrogen produced at the bus refuelling location operated independently of the WWTP. The system response was analysed using a Microsoft Excel simulation model with hourly time steps over a 12-month time frame. The model included a control scheme for the reliable supply of hydrogen for public transport and oxygen to the WWTP and considered expected reductions in carbon intensity of the national grid level of solar PV curtailment electrolyser efficiency and size of the solar PV system. Results showed that by 2031 when Australia’s national electricity is forecast to achieve a carbon intensity of less than 0.186 kg CO2-e/kWh integrating water electrolysis at a municipal WWTP for producing hydrogen for use in local hydrogen buses produced less carbon emissions than continuing to use diesel buses and offsetting emissions by exporting renewable electricity to the grid. By 2034 an annual reduction of 390 t–CO2–e is expected after changing to the integrated configuration. Considering electrolyser efficiency improvements and curtailment of renewable electricity the reduction increases to 872.8 t–CO2–e.

Decarbonisation of the iron and steel industry would require the use of innovative low-carbon production technologies. Use of 100% hydrogen in a shaft furnace (SF) to reduce iron ore has the potential to reduce emissions from iron and steel production significantly. In this work results from the techno-economic assessment of a H2-SF connected to an electric arc furnace(EAF) for steel production are presented under two scenarios. In the first scenario H2 is produced from molten metal methane pyrolysis in an electrically heated liquid metal bubble column reactor. Grid connected low-temperature alkaline electrolyser was considered for H2 production in the second scenario. In both cases 59.25 kgH2 was required for the production of one ton of liquid steel (tls). The specific energy consumption (SEC) for the methane pyrolysis based system was found to be 5.16 MWh/tls. The system used 1.51 MWh/tls of electricity and required 263 kg/tls of methane corresponding to an energy consumption of 3.65 MWh/tls. The water electrolysis based system consumed 3.96 MWh/tls of electricity at an electrolyser efficiency of 50 KWh/kgH2. Both systems have direct emissions of 129.4 kgCO2/tls. The indirect emissions are dependent on the source of natural gas pellet making process and the grid-emission factor. Indirect emissions for the electrolysis based system could be negligible if the electricity is generated from renewable energy sources. The levellized cost of production(LCOP) was found to be $631 and $669 respectively at a discount rate of 8% for a plant-life of 20 years. The LCOP of a natural gas reforming based direct reduction steelmaking plant of operating under similar conditions was found to be $414. Uncertainty analysis was conducted for the NPV and IRR values.

With the growing demand for green technologies hydrogen energy devices such as Proton Exchange Membrane (PEM) fuel cells and water electrolysers have received accelerated developments. However the materials and manufacturing cost of these technologies are still relatively expensive which impedes their widespread commercialization. Additive Manufacturing (AM) commonly termed 3D Printing (3DP) with its advanced capabilities could be a potential pathway to solve the fabrication challenges of PEM parts. Herein in this paper the research studies on the novel AM fabrication methods of PEM components are thoroughly reviewed and analysed. The key performance properties such as corrosion and hydrogen embrittlement resistance of the additively manufactured materials in the PEM working environment are discussed to emphasise their reliability for the PEM systems. Additionally the major challenges and required future developments of AM technologies to unlock their full potential for PEM fabrication are identified. This paper provides insights from the latest research developments on the significance of advanced manufacturing technologies in developing sustainable energy systems to address the global energy challenges and climate change effects.

As a clean and renewable energy source for sustainable development hydrogen energy has gained a lot of attention from the general public and researchers. Hydrogen production by electrolysis of water is the most important approach to producing hydrogen and it is also the main way to realize carbon neutrality. In this paper the main technologies of hydrogen production by electrolysis of water are discussed in detail; their characteristics advantages and disadvantages are analyzed; and the selection criteria and design criteria of catalysts are presented. The catalysts used in various hydrogen production technologies and their characteristics are emphatically expounded aiming at optimizing the existing catalyst system and developing new high-performance high-stability and low-cost catalysts. Finally the problems and solutions in the practical design of catalysts are discussed and explored.

Offshore wind power stands out as a promising renewable energy source offering substantial potential for achieving low carbon emissions and enhancing energy security. Despite its potential the expansion of offshore wind power faces considerable constraints in offshore power transmission. Hydrogen production derived from offshore wind power emerges as an efficient solution to overcome these limitations and effectively transport energy. This study systematically devises diverse hydrogen energy supply chains tailored to the demands of the transportation and chemical industries meticulously assessing the levelized cost of hydrogen (LCOH). Our findings reveal that the most cost-efficient means of transporting hydrogen to the mainland is through pipelines particularly when the baseline distance is 50 km and the baseline electricity price is 0.05 USD/kWh. Notably delivering hydrogen directly to the port via pipelines for chemical industries proves considerably more economical than distributing it to hydrogen refueling stations with a minimal cost of 3.6 USD/kg. Additionally we assessed the levelized cost of hydrogen (LCOH) for supply chains that transmit electricity to ports via submarine cables before hydrogen production and subsequent distribution to chemical plants. In comparison to offshore hydrogen production routes these routes exhibit higher costs and reduced competitiveness. Finally a sensitivity analysis was undertaken to scrutinize the impact of delivery distance and electricity prices on LCOH. The outcomes underscore the acute sensitivity of LCOH to power prices highlighting the potential for substantial reductions in hydrogen prices through concerted efforts to lower electricity costs.

Pink hydrogen is the name given to the technological variant of hydrogen generation from nuclear energy. This technology aims to address the environmental challenges associated with conventional hydrogen production positioning itself as a more sustainable and eco-efficient alternative while offering a viable alternative to nuclear power as a source of electricity generation. The present research analyzes the landscape of pink hydrogen research an innovative strand of renewable energy research. The methodology included a comprehensive search of scientific databases which revealed a steady increase in the number of publications in recent years. This increase suggests a growing interest in and recognition of the importance of pink hydrogen in the transition to cleaner and more sustainable energy sources. The results reflect the immaturity of this technology where there is no single international strategy and where there is some diversity of research topic areas as well as a small number of relevant topics. It is estimated that the future development of Gen IV nuclear reactors as well as Small Modular Reactor (SMR) designs will also favor the implementation of pink hydrogen.

Hydrogen a green energy carrier is one of the most promising energy sources. However，it is currently mainly produced from depleting fossil fuels with high carbon emissions which has serious negative effects on the economy and environment. To address this issue sustainable hydrogen production from bio-energy with carbon capture and storage (HyBECCS) is an ideal technology to reduce global carbon emissions while meeting energy demand. This review presents an overview of the latest progress in alkaline thermal treatment (ATT) of biomass for hydrogen production with carbon storage especially focusing on the technical characteristics and related challenges from an industrial application perspective. Additionally the roles of alkali and catalyst in the ATT process are critically discussed and several aspects that have great influences on the ATT process such as biomass types reaction parameters and reactors are expounded. Finally the potential solutions to the general challenges and obstacles to the future industrial-scale application of ATT of biomass for hydrogen production are proposed.

H2 production via membrane-assisted steam methane reforming (MA-SMR) can ensure higher energy efficiency and lower emissions compared to conventional reforming processes (SMR). Ceramic-supported Pd–Ag membranes have been extensively investigated for membrane-assisted steam methane reforming applications with outstanding performance. However costs sealings for integration in the reactor structure and resistance to solicitations remain challenging issues. In this work the surface quality of a low-cost porous Hastelloy-X filter is improved by asymmetric filling with α-Al2O3 of decreasing size and deposition of γ-Al2O3 as an interdiffusion barrier. On the modified support a thin Pd–Ag layer was deposited via electroless plating (ELP) resulting in a membrane with H2/N2 selectivity >10000. The permeation characteristics of the membrane were studied followed by testing for membrane-assisted methane steam reforming. The results showed the ability of the membrane reactor to overcome thermodynamic conversion of the conventional process for all explored operating conditions as well as ensuring 99.3% H2 purity in the permeate stream at 500 ◦C and 4 bar.

The demand for green hydrogen as an energy carrier is projected to exceed 350 million tons per year by 2050 driven by the need for sustainable distribution and storage of energy generated from sources. Despite its potential hydrogen production currently faces challenges related to cost efficiency compliance monitoring and safety. This work proposes Hydrogen 4.0 a cyber–physical approach that leverages Industry 4.0 technologies—including smart sensing analytics and the Internet of Things (IoT)—to address these issues in hydrogen energy plants. Such an approach has the potential to enhance efficiency safety and compliance through real-time data analysis predictive maintenance and optimised resource allocation ultimately facilitating the adoption of renewable green hydrogen. The following sections break down conventional hydrogen plants into functional blocks and discusses how Industry 4.0 technologies can be applied to each segment. The components benefits and application scenarios of Hydrogen 4.0 are discussed while how digitalisation technologies can contribute to the successful integration of sustainable energy solutions in the global energy sector is also addressed.

Reactor structure design plays an important role in the performance of solar-thermal methane reforming reactors. Based on a conventional preheating reactor this study proposed a cylindrical solar methane reforming reactor with multiple inlets to vary the temperature field distribution which improved the temperature of the reaction region in the reactor thereby improving the reactor performance. A multi-physical model that considers mass momentum species and energy conservation as well as thermochemical reaction kinetics of methane reforming was applied to numerically investigate the reactor performance and analyze the factors that affect performance improvement. It was found that compared with a conventional preheating reactor the proposed cylindrical reactor with inner and external inlets for gas feeding enhanced heat recovery from the exhausted gas and provided a more suitable temperature field for the reaction in the reactor. Under different operating conditions the methane conversion in the cylindrical reactor with multi-inlet increased by 9.5% to 19.1% and the hydrogen production was enhanced by 12.1% to 40.3% in comparison with the conventional design even though the total reaction catalyst volume was reduced.

The natural gas (NG) reforming is currently one of the low-cost methods for hydrogen production. However the mixture of H2 and CO2 in the produced gas inevitably includes CO2 and necessitates the costly CO2 separation. In this work a novel double chemical looping involving both combustion (CLC) and sorption-enhanced reforming (SE-CLR) was proposed towards the co-production of H2 and CO (CLC-SECLRHC) in two separated streams. CLC provides reactant CO2 and energy to feed SECLRHC which generates hydrogen in a higher purity as well as the calcium cycle to generate CO in a higher purity. Techno-economic assessment of the proposed system was conducted to evaluate its efficiency and economic competitiveness. Studies revealed that the optimal molar ratios of oxygen carrier (OC)/NG and steam/NG for reforming were recommended to be 1.7 and 1.0 respectively. The heat integration within CLC and SECLRHC units can be achieved by circulating hot OCs. The desired temperatures of fuel reactor (FR) and reforming reactor (RR) should be 850 °C and 600 °C respectively. The heat coupling between CLC and SECLRHC units can be realized via a jacket-type reactor and the NG split ratio for reforming and combustion was 0.53:0.47. Under the optimal conditions the H2 purity the H2 yield and the CH4 conversion efficiency were 98.76% 2.31 mol mol-1 and 97.96% respectively. The carbon and hydrogen utilization efficiency respectively were 58.60% and 72.45% in terms of the total hydrogen in both steam and NG. The exergy efficiency of the overall process reached 70.28%. In terms of the conventional plant capacity (75×103 t y-1 ) and current raw materials price (2500 $ t-1 ) the payback period can be 6.2 years and the IRR would be 11.5 demonstrating an economically feasible and risk resistant capability.

Today we are joined by our good friends from Enapter. The company is a leader in the clean hydrogen sector focused on AEM electrolyzer technology and innovative software solutions that make it possible to rapidly deploy and scale hydrogen production assets. For those who follow the hydrogen sector regularly it’s been hard not to hear Enapter-related news in 2021 and its impressive trajectory as they have gone public announced the plans for a brand new production facility in Germany (on which they have now begun construction) and most recently the announcement that Enapter was selected as the winner of the prestigious Earthshot prize. To do that we are absolutely delighted to have with us all the way from his home base in Thailand Thomas Chrometzka Chief Strategy Officer at Enapter and one of the people that we enjoy having on the show so much that we have brought him back again to fill us in on what he and Enapter are up to and what they have planned for the future of hydrogen.

The podcast can be found on their website

Hydrogen is a crucial raw materials to other industries. Globally nearly 90% of the hydrogen or HyCO gas produced is consumed by the ammonia methanol and oil refining industries. In the future hydrogen could play an important role in the decarbonisation of transport fuel (i.e. use of fuel cell vehicles) and space heating (i.e. industrial commercial building and residential heating). This paper summarizes the results of the feasibility study carried out by Amec Foster Wheeler for the IEA Greenhouse Gas R&D Programme (IEA GHG) with the purpose of evaluating the performance and costs of a modern steam methane reforming without and with CCS producing 100000 Nm3 /h H2 and operating as a merchant plant. This study focuses on the economic evaluation of five different alternatives to capture CO2 from SMR. This paper provides an up-to-date assessment of the performance and cost of producing hydrogen without and with CCS based on technologies that could be erected today. This study demonstrates that CO2 could be captured from an SMR plant with an overall capture rate ranging between 53 to 90%. The integration of CO2 capture plant could increase the NG consumption by -0.03 to 1.41 GJ per Nm3 /h of H2. The amount of electricity exported to the grid by the SMR plant is reduced. The levelised cost of H2 production could increase by 2.1 to 5.1 € cent per Nm3 H2 (depending on capture rate and technology selected). This translates to a CO2 avoidance cost of 47 to 70 €/t.

Hydrogen production and refueling integrated station can play an important role in the development of hydrogen transportation and fuel cell vehicles and actively promote the energy transformation. By using DC system for hydrogen production and refueling the conversion links can be reduced and the system efficiency can be effectively improved. In this paper a new scheme of DC interconnection for hydrogen production and refueling integrated station is proposed and the modular modeling and operation capability evaluation method are proposed including the characteristic analysis of integrated station the modular modeling and evaluation method for multiple integrated stations under DC interconnection. The DC interconnection system of five integrated stations is constructed and operation capability improvement of integrated stations after adopting the innovative DC interconnection scheme is analyzed. On this basis the system simulation model based on MATLAB/Simulink and physical test platform are built to verify the effectiveness of the theoretical analysis.

Hydrogen produced in a polymer electrolyte membrane (PEM) electrolyzer must be stored under high pressure. It is discussed whether the gas should be compressed in subsequent gas compressors or by the electrolyzer. While gas compressor stages can be reduced in the case of electrochemical compression safety problems arise for thin membranes due to the undesired permeation of hydrogen across the membrane to the oxygen side forming an explosive gas. In this study a PEM system is modeled to evaluate the membrane-specific total system efficiency. The optimum efficiency is given depending on the external heat requirement permeation cell pressure current density and membrane thickness. It shows that the heat requirement and hydrogen permeation dominate the maximum efficiency below 1.6 V while above the cell polarization is decisive. In addition a pressure-optimized cell operation is introduced by which the optimum cathode pressure is set as a function of current density and membrane thickness. This approach indicates that thin membranes do not provide increased safety issues compared to thick membranes. However operating an N212-based system instead of an N117-based one can generate twice the amount of hydrogen at the same system efficiency while only one compressor stage must be added.

This study provides H2 gas as a renewable energy source from sewage water splitting reaction using a PMT/Au photocathode. So this study has a dual benefit for hydrogen generation; at the same time it removes the contaminations of sewage water. The preparation of the PMT is carried out through the polymerization process from an acid medium. Then the Au sputter was carried out using the sputter device under different times (1 and 2 min) for PMT/Au-1 min and PMT/Au-2min respectively. The complete analyses confirm the chemical structure such as XRD FTIR HNMR SEM and Vis-UV optical analyses. The prepared electrode PMT/Au is used for the hydrogen generation reaction using Na2S2O3 or sewage water as an electrolyte. The PMT crystalline size is 15 nm. The incident photon to current efficiency (IPCE) efficiency increases from 2.3 to 3.6% (at 390 nm) and the number of H2 moles increases from 8.4 to 33.1 mmol h−1 cm−2 for using Na2S2O3 and sewage water as electrolyte respectively. Moreover all the thermodynamic parameters such as activation energy (Ea) enthalpy (∆H*) and entropy (∆S*) were calculated; additionally a simple mechanism is mentioned for the water-splitting reaction.

Chemical looping with iron-based oxygen carriers enables the production of hydrogen from various fossil and biogenic primary energy sources. In applications with real producer gases such as biogas or gasified biomass hydrogen sulfide represents one of the most challenging contaminants. The impact of H2S on the reactivity of a Fe2O3/Al2O3 oxygen carrier material in chemical looping hydrogen production was investigated in the present work. First potential sulfur deactivation mechanisms are discussed in detail on the basis of thermodynamic data. Afterwards an experimental study in a fixed-bed reactor system gave experimental evidence on the fate of sulfur in chemical looping hydrogen systems. The chemisorption of hydrogen sulfide (H2S) was identified as the main cause for the accumulative adsorption of H2S in the reduction phase and was confirmed by ex-situ ICP-EOS analysis. In the subsequent steam oxidation step significant quantities of H2S were released resulting in an undesirable contamination of the hydrogen product gas. The reason was found as weakened sulfur bonds through increasing reactor temperatures caused by the exothermic oxidation reactions. In additional air oxidation steps no further contaminants as sulfur dioxide were identified. A profound interpretation was achieved through the fulfillment of the overall sulfur mass balance within a mean deviation of 3.7%. Quantitative investigations showed that the hydrogen consumption decreased by 12% throughout the reduction phase in the event of 100 ppm H2S in the feed gas

The Life Cycle Sustainability Assessment (LCSA) is a proven method for sustainability assessment. However the interpretation phase of an LCSA is challenging because many different single results are obtained. Additionally performing a Multi-Criteria Decision Analysis (MCDA) is one way—not only for LCSA—to gain clarity about how to interpret the results. One common form of MCDAs are outranking methods. For these type of methods it becomes of utmost importance to clarify when results become preferable. Thus thresholds are commonly used to prevent decisions based on results that are actually indifferent between the analyzed options. In this paper a new approach is presented to identify and quantify such thresholds for Preference Ranking Organization METHod for Enrichment Evaluation (PROMETHEE) based on uncertainty of Life Cycle Impact Assessment (LCIA) methods. Common thresholds and this new approach are discussed using a case study on finding a preferred location for sustainable industrial hydrogen production comparing three locations in European countries. The single LCSA results indicated different preferences for the environmental economic and social assessment. The application of PROMETHEE helped to find a clear solution. The comparison of the newly-specified thresholds based on LCIA uncertainty with default thresholds provided important insights of how to interpret the LCSA results regarding industrial hydrogen production.

A steam methane reforming reactor is a key equipment in hydrogen production and numerical analysis and process control can provide a critical insight into its reforming mechanisms and flexible operation in real engineering applications. The present paper firstly studies the transport phenomena in an industrial-scale steam methane reforming reactor by transient numerical simulations. Wall effect and local non thermal equilibrium is considered in the simulations. A temperature profile of the tube outer wall is given by user defined functions integrated into the ANSYS FLUENT software. Dynamic simulations show that the species distribution is closely related to the temperature distribution which makes the temperature of the reactor tube wall an important factor for the hydrogen production of the reformer and the thermal conductivity of the catalyst network is crucial in the heat transfer in the reactor. Besides there exists a delay of the reformer's hydrogen production when the temperature profile of the tube wall changes. Among inlet temperature inlet mass flow rate and inlet steam-to-carbon (S/C) ratio the mass flow rate is the most influencing factor for the hydrogen production. The dynamic matrix control (DMC) scheme is subsequently designed to manipulate the mole fraction of hydrogen of the outlet to the target value by setting the temperature profile trajectory of the reforming tube with time. The proportional-integral control strategy is also studied for comparison. The closed-loop simulation results show that the proposed DMC control strategy can reduce the overshoot and have a small change of the input variable. In addition the disturbances of feed disturbance can also be well rejected to assure the tracking performance indicating the superiority of the DMC controller. All the results give insight to the theoretical analysis and controller design of a steam methane reformer and demonstrate the potential of the CFD modeling in study the transport mechanism and the idea of combining CFD modelling with controller design for the real application.

Hydrogen is increasingly being viewed as a significant fuel for future industrial processes as it offers pathways to zero emission. The UK sees hydrogen as one of a handful of low-carbon solutions for transition to net zero. Currently most hydrogen production is from steam reforming of natural gas or coal gasification both of which involve the release of carbon dioxide. Hydrogen production from mini decentralised grids via a thermochemical process coupled with electricity production could offer favourable economics for small modular reactors (SMRs) whereby demand or grid management as a solution would include redirecting the power for hydrogen production when electricity demand is low. It also offers a clean-energy alternative to the aforementioned means. SMRs could offer favourable economics due to their flexible power system as part of the dual-output function. This study objective is to investigate the critical performance parameters associated with the nuclear power plant (NPP) the cycle working fluids and control-system design for switching between electricity and hydrogen demand to support delivery as part of a mini grid system for a reactor power delivering up to approximately 600 MWth power. The novelty of the work is in the holistic parametric analysis undertaken using a novel in-house tool which analyses the NPP using different working fluids with a control function bolt-on at the offtake for hydrogen production. The results indicate that the flow conditions at the offtake can be maintained. The choice of working fluids affects the pressure component. However the recuperator and heat-exchanger effectiveness are considered as efficiency-limiting factors for hydrogen production and electricity generation. As such the benefit of high-technology heat exchangers cannot be underestimated. This is also true when deciding on the thermochemical process to bolt onto the plant. The temperature of the gas at the end of the pipeline should also be considered to ensure that the minimum temperature-requirement status for hydrogen production is me