Production & Supply Chain
Conceptual Design of a Process for Hydrogen Production from Waste Biomass and its Storage in form of Liquid Ammonia
Feb 2023
Publication
In this work we present the simulation of a plant for the exploitation of renewable hydrogen (e.g. from biomass gasification) with production of renewable ammonia as hydrogen vector and energy storage medium. The simulation and sizing of all unit operations were performed with Aspen Plus® as software. Vegetable waste biomass is used as raw material for hydrogen production more specifically pine sawdust.<br/>The hydrogen production process is based on a gasification reactor operating at high temperature (700–800 °C) in the presence of a gasifying agent such as air or steam. At the outlet a solid residue (ash) and a certain amount of gas which mainly contains H2 CH4 CO and some impurities (e.g. sulphur or chlorine compounds) are obtained. Subsequently this gas stream is purified and treated in a series of reactors in order to maximize the hydrogen yield. In fact after the removal of the sulphur compounds through an absorption column with MEA (to avoid poisoning of the catalytic processes) 3 reactors are arranged in series: Methane Steam Reforming (MSR) High temperature Water-Gas Shift (HT-WGS) Low temperature Water-Gas Shift (LT-WGS).<br/>In the first MSR reactor methane reacts at 1000 °C in presence of steam and a nickel-based catalyst in order to obtain mainly H2 CO and CO2. Subsequently two steps of WGS are present to convert most of the CO into H2 and CO2. Also these reactions are carried out in the presence of a catalyst and with an excess of water.<br/>All the oxygenated compounds must be carefully eliminated: the remaining traces of CO are methanated while CO2 is removed by a basic scrubbing with MEA (35 wt%) inside an absorption column. The Haber-Bosch synthesis of ammonia was carried out at 200 bar and in a temperature range between 300 and 400 °C using two catalysts: Fe (wustite) and Ru/C.<br/>As overall balance from an hourly flow rate of 1000 kg of dry biomass and 600 kg of nitrogen 550 kg of NH3 at 98.8 wt% were obtained demonstrating the proof of concept of this newly designed process for the production of hydrogen from renewable waste biomass and its transformation into a liquid hydrogen vector to be easily transported and stored.
Evaluating Freshwater, Desalinated Water, and Treated Brine as Water Feed for Hydrogen Production in Arid Regions
Aug 2025
Publication
Hydrogen production is increasingly vital for global decarbonization but remains a waterand energy-intensive process especially in arid regions. Despite growing attention to its climate benefits limited research has addressed the environmental impacts of water sourcing. This study employs a life cycle assessment (LCA) approach to evaluate three water supply strategies for hydrogen production: (1) seawater desalination without brine treatment (BT) (2) desalination with partial BT and (3) freshwater purification. Scenarios are modeled for the United Arab Emirates (UAE) Australia and Spain representing diverse electricity mixes and water stress conditions. Both electrolysis and steam methane reforming (SMR) are evaluated as hydrogen production methods. Results show that desalination scenarios contribute substantially to human health and ecosystem impacts due to high energy use and brine discharge. Although partial BT aims to reduce direct marine discharge impacts its substantial energy demand can offset these benefits by increasing other environmental burdens such as marine eutrophication especially in regions reliant on carbon-intensive electricity grids. Freshwater scenarios offer lower environmental impact overall but raise water availability concerns. Across all regions feedwater for SMR shows nearly 50% lower impacts than for electrolysis. This study focuses solely on the environmental impacts associated with water sourcing and treatment for hydrogen production excluding the downstream impacts of the hydrogen generation process itself. This study highlights the trade-offs between water sourcing brine treatment and freshwater purification for hydrogen production offering insights for optimizing sustainable hydrogen systems in water-stressed regions.
Biohydrogen Production: Strategies to Improve Process Efficiency through Microbial Routes
Apr 2015
Publication
The current fossil fuel-based generation of energy has led to large-scale industrial development. However the reliance on fossil fuels leads to the significant depletion of natural resources of buried combustible geologic deposits and to negative effects on the global climate with emissions of greenhouse gases. Accordingly enormous efforts are directed to transition from fossil fuels to nonpolluting and renewable energy sources. One potential alternative is biohydrogen (H2) a clean energy carrier with high-energy yields; upon the combustion of H2 H2O is the only major by-product. In recent decades the attractive and renewable characteristics of H2 led us to develop a variety of biological routes for the production of H2. Based on the mode of H2 generation the biological routes for H2 production are categorized into four groups: photobiological fermentation anaerobic fermentation enzymatic and microbial electrolysis and a combination of these processes. Thus this review primarily focuses on the evaluation of the biological routes for the production of H2. In particular we assess the efficiency and feasibility of these bioprocesses with respect to the factors that affect operations and we delineate the limitations. Additionally alternative options such as bioaugmentation multiple process integration and microbial electrolysis to improve process efficiency are discussed to address industrial-level applications.
An Integrated–Intensified Adsorptive-Membrane Reactor Process for Simultaneous Carbon Capture and Hydrogen Production: Multi-Scale Modeling and Simulation
Aug 2025
Publication
Minimizing carbon dioxide emissions is crucial due to the generation of energy from fossil fuels. The significance of carbon capture and storage (CCS) technology which is highly successful in mitigating carbon emissions has increased. On the other hand hydrogen is an important energy carrier for storing and transporting energy and technologies that rely on hydrogen have become increasingly promising as the world moves toward a more environmentally friendly approach. Nevertheless the integration of CCS technologies into power production processes is a significant challenge requiring the enhancement of the combined power generation–CCS process. In recent years there has been a growing interest in process intensification (PI) which aims to create smaller cleaner and more energy efficient processes. The goal of this research is to demonstrate the process intensification potential and to model and simulate a hybrid integrated–intensified adsorptive-membrane reactor process for simultaneous carbon capture and hydrogen production. A comprehensive multi-scale multi-phase dynamic computational fluid dynamics (CFD)-based process model is constructed which quantifies the various underlying complex physicochemical phenomena occurring at the pellet and reactor levels. Model simulations are then performed to investigate the impact of dimensionless variables on overall system performance and gain a better understanding of this cyclic reaction/separation process. The results indicate that the hybrid system shows a steady-state cyclic behavior to ensure flexible operating time. A sustainability evaluation was conducted to illustrate the sustainability improvement in the proposed process compared to the traditional design. The results indicate that the integrated–intensified adsorptive-membrane reactor technology enhances sustainability by 35% to 138% for the chosen 21 indicators. The average enhancement in sustainability is almost 57% signifying that the sustainability evaluation reveals significant benefits of the integrated–intensified adsorptive-membrane reactor process compared to HTSR + LTSR.
Synergizing Water Desalination and Hydrogen Production using Solar Stills with Novel Sensible Heat Storage and an Alkaline Electrolyzer
Dec 2024
Publication
This study tested a cogeneration (desalination/hydrogen production) system with natural and black sand as sensible heat storage considering the thermal efficiencies environmental impact water quality cost aspects and hydrogen generation rate. The black sand-modified distiller attained the highest water production of 4645 mL more than the conventional distiller by 1595 mL. It also offered better energy and exergy efficiencies of 45.26% and 3.72% respectively compared to 32.10% and 2.19% for the conventional one. Both modified distillers showed impressive improvements in water quality by significant reductions in total dissolved solids (TDS) from 29300 mg/L to 60–61 mg/L. Moreover the black sand-modified still reduced chemical oxygen demand (COD) to 135 mg/L. The production cost was minimized by using black sand to 0.0111$/L higher than one-fifth in the case of the lab-based distiller. Regarding hydrogen production the highest rate was obtained using distilled water from a labbased distiller of 0.742 gH₂/hr with an energy efficiency of 11.00%; however it was not much higher than the case of black sand-modified still (0.736 gH₂/hr production rate and 10.91% efficiency). Moreover the black sand-modified still showed the highest annual exergy output of 70.4 kWh/year with a significant annual decarbonization of 1.69 ton-CO2.
Enhancing Hydrogen Production from Chlorella sp. Biomass by Pre-Hydrolysis with Simultaneous Saccharification and Fermentation (PSSF)
Mar 2019
Publication
Simultaneous saccharification and fermentation (SSF) and pre-hydrolysis with SSF (PSSF) were used to produce hydrogen from the biomass of Chlorella sp. SSF was conducted using an enzyme mixture consisting of 80 filter paper unit (FPU) g-biomass−1 of cellulase 92 U g-biomass−1 of amylase and 120 U g-biomass−1 of glucoamylase at 35 ◦C for 108 h. This yielded 170 mL-H2 g-volatile-solids−1 (VS) with a productivity of 1.6 mL-H2 g-VS−1 h −1 . Pre-hydrolyzing the biomass at 50 ◦C for 12 h resulted in the production of 1.8 g/L of reducing sugars leading to a hydrogen yield (HY) of 172 mL-H2 g-VS−1 . Using PSSF the fermentation time was shortened by 36 h in which a productivity of 2.4 mL-H2 g-VS−1 h −1 was attained. To the best of our knowledge the present study is the first report on the use of SSF and PSSF for hydrogen production from microalgal biomass and the HY obtained in the study is by far the highest yield reported. Our results indicate that PSSF is a promising process for hydrogen production from microalgal biomass.
Process Flexibility of Soprtion-enhanced Steam Reforming for Hydrogen Production from Gas Mixtures Representative of Biomass-derived Syngas
Sep 2025
Publication
Hydrogen is a critical enabler of CO2 valorization essential for the synthesis of carbon-neutral fuels such as efuels and advanced biofuels. Biohydrogen produced from renewable biomass is a stable and dispatchable source of low-carbon hydrogen helping to address supply fluctuations caused by the intermittency of renewable electricity and the limited availability of electrolytic hydrogen. This study experimentally demonstrates that sorption-enhanced steam reforming (SESR) is a robust and adaptable process for hydrogen production from biomass-derived syngas-like gas streams. By incorporating in situ CO2 capture SESR overcomes the thermodynamic limits of conventional reforming achieving high hydrogen yields (>96 %) and purities (up to 99.8 vol%) across a wide range of syngas compositions. The process maintains high conversion efficiency despite variations in CO CH4 and CO2 concentrations and sustains performance even with H2-rich feeds conditions that typically inhibit reforming reactions. Among the operating parameters temperature has the greatest influence on performance followed by the steam-to-carbon ratio and space velocity. Multi-objective optimization shows that SESR can maintain high hydrogen yield (>96 %) selectivity (>99 %) and purity (>99.5 vol%) within a moderately flexible operating window. Methane reforming is identified as the main performance-limiting step with a stronger constraint on H2 yield and purity than CO conversion through the water–gas shift reaction. In addition to hydrogen SESR produces a concentrated CO2 stream suitable for downstream utilization or storage. These results support the potential of SESR as a flexible and efficient approach for hydrogen production from heterogeneous renewable feedstocks.
Towards Water-conscious Green Hydrogen and Methanol: A Techno-economic Review
Jan 2025
Publication
To enable a sustainable and socially accepted hydrogen and methanol economy it is crucial to prioritize green and water-conscious production. In this review we reveal that there is a significant research gap regarding comprehensive assessments of such production methods. We present an innovative process chain consisting of adsorption-based direct air capture solid oxide electrolysis and methanol synthesis to address this issue. To allow future comprehensive techno-economic assessments we perform a systematic literature review and harmonization of the techno-economic parameters of the process chain’s technologies. Based on the conducted literature review we find that the long-term median specific energy demand of adsorption-based direct air capture is expected to decrease to 204 kWhel/tCO2 and 1257 kWhth/tCO2 while the capture cost is expected to decrease to 162 €2024/tCO2 with a relative high uncertainty. The evaluated sources expect a future increase in system efficiency of solid oxide electrolysis to 80% while the purchase equipment costs are expected to decrease significantly. Finally we demonstrate the feasibility of the process chain from a technoeconomic perspective and show a potential reduction in external heat demand of the DAC unit of up to 34% when integrated in the process chain.
A Novel Flow Channel Design for Improving Water Splitting in Anion Exchange Membrane Electrolysers
Jul 2025
Publication
Anion exchange membrane (AEM) alkaline water electrolyser s are a promising reactor in large - scale industrial green hydrogen production. However the configurations of electrolysers especially the flow channel are not well optimised. In this work we demonstrate that the several existing flow channel designs e.g. single serpentine parallel pin can significantly affect the AEM electrolysers’ performance. The two -phase flow behaviours associated with the mass transfer of both electrolyte and produced gas bubbles within these flow channels have been simulated and thoroughly studied via a three -dimensional (3D) computational fluid dynamics (CFD) model . A novel flow channel design named Parpentine that combines the features of Parallel and Single serpentine designs is proposed with an optimised balance among the electrolyte flow distribution bubble removal rate and pressure drop. The superiority of the Parpentine flow channel is well verified in practical AEM water electrolyser experiments using commercial Ni foam and self-designed efficient NiFe and NiMo electrodes. At a cell voltage of 2.5 V compared to the benchmark serpentine design a 12.4% ~ 34.8% increase in hydrogen production efficiency can be achieved in both 1 M and 5 M KOH conditions at room temperature. This work discovers a novel design and a new method for highly efficient water electrolysers.
Biomass-based Chemical Looping Hydrogen Production: Performance Evaluation and Economic Viability
Oct 2025
Publication
Chemical looping hydrogen generation (CLHG) from biomass is a promising technology for producing carbonnegative hydrogen. However achieving autothermal operation without sacrificing hydrogen yield presents a significant thermodynamic challenge. This study proposes and evaluates a novel thermal management strategy that enables a self-sustaining process by balancing the system’s heat load with its internal exothermic reactions. A comprehensive analysis was conducted using process simulation to assess the system’s thermodynamic performance identify key sources of inefficiency through exergy analysis and determine its economic viability via a detailed techno-economic assessment. The results show that a 200 MWth CLHG plant can produce 2.06 t-H2/h with a hydrogen production efficiency and exergy efficiency of 34.46 % and 44.4 % respectively. The exergy analysis identified the fuel reactor as the largest source of thermodynamic inefficiency accounting for 66.4 % of the total exergy destruction. The techno-economic analysis yielded a base-case minimum selling price (MSP) of hydrogen of 2.63 USD/kg a rate competitive with other carbon-capture-enabled hydrogen production methods. Sensitivity analysis confirmed that the MSP is most influenced by biomass price and discount rate. Crucially the system’s carbon-negative nature allows it to leverage carbon pricing schemes which can significantly improve its economic performance. Under the EU’s current carbon price the MSP falls to 0.98 USD/kg-H2 and it can become negative in regions with higher carbon taxes suggesting profitability from carbon credits alone. This study demonstrates that the proposed CLHG system is a technically robust and economically compelling pathway for clean hydrogen production particularly in regulatory environments that incentivize carbon capture.
Hydrogen Production via Ammonia Decomposition: Kinetic Analysis
Jul 2025
Publication
Ammonia (NH3) has emerged as a promising hydrogen carrier due to its high hydrogen content favourable storage and transport properties and carbon-free utilisation. Its ability to be stored as a liquid under relatively mild conditions and its compatibility with existing industrial infrastructure make it an efficient and scalable solution for hydrogen distribution. This study conducts a detailed investigation into the kinetics of ammonia decomposition over rutheniumbased catalysts which are known for their high catalytic activity for ammonia cracking. Experimental data across a wide range of operating conditions are used to validate the proposed models with a promising catalyst (0.5 wt.% Ru/Al2O3). The study employs kinetic models based on different theoretical frameworks such as the Langmuir isotherm the Temkin-Pyzhev approach and the microkinetic model focusing on evaluating various rate-determining steps. A comparison of these models shows that those that consider nitrogen desorption a ratedetermining step provide the best predictions of NH3 conversion effectively capturing the dependencies on temperature and feed molar fractions of reactants and products. This multifaceted approach integrates experimental data with proposed kinetic models contributing to a better understanding of NH3 decomposition through parameter optimisation. The findings provide valuable insights for modelling catalytic reactors optimising conditions and enhancing catalyst performance for efficient hydrogen production from ammonia.
Production of Hydrogen-Rich Syngas via Biomass-Methane Co-Pyrolysis: Thermodynamic Analysis
Oct 2025
Publication
This study presents a thermodynamic equilibrium analysis of hydrogen-rich syngas production via biomass–methane co-pyrolysis employing the Gibbs free energy minimization method. A critical temperature threshold at 700 ◦C is identified below which methanation and carbon deposition are thermodynamically favored and above which cracking and reforming reactions dominate enabling high-purity syngas generation. Methane addition shifts the reaction pathway towards increased reduction significantly enhancing carbon and H2 yields while limiting CO and CO2 emissions. At 1200 ◦C and a 1:1 methane-tobiomass ratio cellulose produces 50.84 mol C/kg 119.69 mol H2/kg and 30.65 mol CO/kg; lignin yields 78.16 mol C/kg 117.69 mol H2/kg and 19.14 mol CO/kg. The H2/CO ratio rises to 3.90 for cellulose and 6.15 for lignin with energy contents reaching 43.16 MJ/kg and 52.91 MJ/kg respectively. Notably biomass enhances methane conversion from 25% to over 53% while sustaining a 67% H2 selectivity. These findings demonstrate that syngas composition and energy content can be precisely controlled via methane co-feeding ratio and temperature offering a promising approach for sustainable tunable syngas production.
Green Hydrogen Production with 25 kW Alkaline Electrolyzer Pilot Plant Shows Hydrogen Flow Rate Exponential Asymptotic Behavior with the Stack Current
Sep 2025
Publication
Green H2 production using electrolyzer technology is an emerging method in the current mandate using renewable-based power sources integrated with electrolyzer technology. Prior research has been extensively studied to understand the effects of intermittent power sources on the hydrogen production output. However in this context the characteristics of the working electrolyzer behave differently under system-level operation. In this paper we investigated a 25 kW alkaline electrolyzer for its stack performance in terms of stack efficiency the stack current vs. stack voltage and the relationship between the H2 flow rate and stack current. It was found that the current of 52 A produces the best system efficiency of 64% under full load operation for 1 h. The H2 flow rate behaves in an exponential asymptotic pattern and it is also found that the ramp-up time for hydrogen generation by the electrolyzer is significantly low thus marking it as an efficient option for producing green hydrogen with the input of a hybrid grid and renewable PV-based power sources. Hydrogen production techno-economic analysis has been conducted and the LCOH is found to be on the higher side for the current electrolyzer under investigation.
Alkaline Electrolysis for Green Hydrogen Production: A Novel, Simple Model for Thermo-electrochemical Coupled System Analysis
Dec 2024
Publication
Alkaline water electrolysis (AWE) is the most mature electrochemical technology for hydrogen production from renewable electricity. Thus its mathematical modeling is an important tool to provide new perspectives for the design and optimization of energy storage and decarbonization systems. However current models rely on numerous empirical parameters and neglect variations of temperature and concentration alongside the electrolysis cell which can impact the application and reliability of the simulation results. Thus this study proposes a simple four-parameter semi-empirical model for AWE system analysis which relies on minimal fitting data while providing reliable extrapolation results. In addition the effect of model dimensionality (i.e. 0D 1/2D and 1D) are carefully assessed in the optimization of an AWE system. The results indicate that the proposed model can accurately reproduce literature data from four previous works (R 2 ≥ 0.98) as well as new experimental data. In the system optimization the trade-offs existing in the lye cooling sizing highlight that maintaining a low temperature difference in AWE stacks (76-80°C) leads to higher efficiencies and lower hydrogen costs.
Optimization of Green Hydrogen Production via Direct Seawater Electrolysis Powered by Hybrid PV-Wind Energy: Response Surface Methodology
Oct 2025
Publication
This study explored the optimization of green hydrogen production via seawater electrolysis powered by a hybrid photovoltaic (PV)-wind system in KwaZulu-Natal South Africa. A Box–Behnken Design (BBD) adapted from Response Surface Methodology (RSM) was utilized to address the synergistic effect of key operational factors on the integration of renewable energy for green hydrogen production and its economic viability. Addressing critical gaps in renewable energy integration the research evaluated the feasibility of direct seawater electrolysis and hybrid renewable systems alongside their techno-economic viability to support South Africa’s transition from a coal-dependent energy system. Key variables including electrolyzer efficiency wind and PV capacity and financial parameters were analyzed to optimize performance metrics such as the Levelized Cost of Hydrogen (LCOH) Net Present Cost (NPC) and annual hydrogen production. At 95% confidence level with regression coefficient (R2 > 0.99) and statistical significance (p < 0.05) optimal conditions of electricity efficiency of 95% a wind-turbine capacity of 4960 kW a capital investment of $40001 operational costs of $40000 per year a project lifetime of 29 years a nominal discount rate of 8.9% and a generic PV capacity of 29 kW resulted in a predictive LCOH of 0.124$/kg H2 with a yearly production of 355071 kg. Within the scope of this study with the goal of minimizing the cost of production the lowest LCOH observed can be attributed to the architecture of the power ratios (Wind/PV cells) at high energy efficiency (95%) without the cost of desalination of the seawater energy storage and transportation. Electrolyzer efficiency emerged as the most influential factor while financial parameters significantly affected the cost-related responses. The findings underscore the technical and economic viability of hybrid renewable-powered seawater electrolysis as a sustainable pathway for South Africa’s transition away from coal-based energy systems.
Evaluation of Green and Blue Hydrogen Production Potential in Saudi Arabia
Sep 2024
Publication
The Kingdom of Saudi Arabia has rich renewable energy resources specifically wind and solar in addition to geothermal beside massive natural gas reserves. This paper investigates the potential of both green and blue hydrogen production for five selected cities in Saudi Arabia. To accomplish the said objective a techno-economic model is formulated. Four renewable energy scenarios are evaluated for a total of 1.9 GW installed capacity to reveal the best scenario of Green Hydrogen Production (GHP) in each city. Also Blue Hydrogen Production (BHP) is investigated for three cases of Steam Methane Reforming (SMR) with different percentages of carbon capture. The economic analysis for both GHP and BHP is performed by calculating the Levelized Cost of Hydrogen (LCOH) and cash flow. The LCOH for GHP range for all cities ($3.27/kg -$12.17/kg)) with the lowest LCOH is found for NEOM city (50% PV and 50% wind) ($3.27/kg). LCOH for BHP are $0.534/kg $0.647/kg and $0.897/kg for SMR wo CCS/U SMR 55% CCS/U and SMR 90% CCS/U respectively.
Impact of an Electrode-diaphragm Gap on Diffusive Hydrogen Crossover in Alkaline Water Electrolysis
Oct 2023
Publication
Hydrogen crossover limits the load range of alkaline water electrolyzers hindering their integration with renewable energy. This study examines the impact of the electrode-diaphragm gap on crossover focusing on diffusive transport. Both finite-gap and zero-gap designs employing the state-of-the-art Zirfon UTP Perl 500 and UTP 220 diaphragms were investigated at room temperature and with a 12 wt% KOH electrolyte. Experimental results reveal a relatively high crossover for a zero-gap configuration which corresponds to supersaturation levels at the diaphragm-electrolyte interface of 8–80 with significant fluctuations over time and between experiments due to an imperfect zero-gap design. In contrast a finite-gap (500 μm) has a significantly smaller crossover corresponding to supersaturation levels of 2–4. Introducing a cathode gap strongly decreases crossover unlike an anode gap. Our results suggest that adding a small cathode-gap can significantly decrease gas impurity potentially increase the operating range of alkaline electrolyzers while maintaining good efficiency.
Status and Perspectives of Key Materials for PEM Electrolyzer
Sep 2024
Publication
Proton exchange membrane water electrolyzer (PEMWE) represents a promising technology for the sustainable production of hydrogen which is capable of efficiently coupling to intermittent electricity from renewable energy sources (e.g. solar and wind). The technology with compact stack structure has many notable advantages including large current density high hydrogen purity and great conversion efficiency. However the use of expensive electrocatalysts and construction materials leads to high hydrogen production costs and limited application. In this review recent advances made in key materials of PEMWE are summarized. First we present a brief overview about the basic principles thermodynamics and reaction kinetics of PEMWE. We then describe the cell components of PEMWE and their respective functions as well as discuss the research status of key materials such as membrane electrocatalysts membrane electrode assemblies gas diffusion layer and bipolar plate. We also attempt to clarify the degradation mechanisms of PEMWE under a real operating environment including catalyst degradation membrane degradation bipolar plate degradation and gas diffusion layer degradation. We finally propose several future directions for developing PEMWE through devoting more efforts to the key materials.
Optimization of Hydrogen Production System Performance Using Photovoltaic/Thermal-Coupled PEM
Oct 2024
Publication
A proton exchange membrane electrolyzer can effectively utilize the electricity generated by intermittent solar power. Different methods of generating electricity may have different efficiencies and hydrogen production rates. Two coupled systems namely PV/T- and CPV/T-coupling PEMEC respectively are presented and compared in this study. A maximum power point tracking algorithm for the photovoltaic system is employed and simulations are conducted based on the solar irradiation intensity and ambient temperature of a specific location on a particular day. The simulation results indicate that the hydrogen production is relatively high between 11:00 and 16:00 with a peak between 12:00 and 13:00. The maximum hydrogen production rate is 99.11 g/s and 29.02 g/s for the CPV/T-PEM and PV/T-PEM systems. The maximum energy efficiency of hydrogen production in CPV/T-PEM and PV/T-PEM systems is 66.7% and 70.6%. Under conditions of high solar irradiation intensity and ambient temperature the system demonstrates higher total efficiency and greater hydrogen production. The CPV/T-PEM system achieves a maximum hydrogen production rate of 2240.41 kg/d with a standard coal saving rate of 15.5 tons/day and a CO2 reduction rate of 38.0 tons/day. Compared to the PV/T-PEM system the CPV/T-PEM system exhibits a higher hydrogen production rate. These findings provide valuable insights into the engineering application of photovoltaic/thermal-coupled hydrogen production technology and contribute to the advancement of this field.
Development of a Novel Renewable Energy-based Integrated System Coupling Biomass and H2S Sources for Clean Hydrogen Production
Oct 2024
Publication
The present work aims to develop a novel integrated energy system to produce clean hydrogen power and biochar. The Palmaria palmata a type of seaweed and hydrogen sulfide from the industrial gaseous waste streams are taken as potential feedstock. A combined thermochemical approach is employed for the processing of both feedstocks. For clean hydrogen production the zinc sulfide thermochemical cycle is employed. Both stoichiometric and non-stoichiometric equilibrium-based models of the proposed plant design are developed in the Aspen Plus software and a comprehensive thermodynamic analysis of the system is also performed by evaluating energy and exergy efficiencies. The study further explores the modeling simulation and parametric analyses of various subsections to enhance the hydrogen and biochar production rate. The parametric analyses show that the first step of the thermochemical cycle (sulfurization reaction) follows stoichiometric pathway and the ZnO to H2S ratio of 1 represents the optimal point for reactant conversion. On the other hand the second step of the thermochemical cycle (regeneration reaction) does not follow a stoichiometric pathway and ZnS conversion of 12.87% is achieved at a high temperature of 1400oC. It is found that a hydrogen production rate of 0.71 mol/s is achieved with the introduction of 0.27 mol/s of H2S. The energy and exergy efficiencies of the zinc sulfide thermochemical cycle are found to be 65.23% and 35.58% respectively. A biochar production rate of 0.024 kg/s is obtained with the Palmaria palmata fed rate of 0.097 kg/s. The Palmaria to biochar energy and exergy efficiencies are found to be 55.43% and 45.91% respectively. The overall energy and exergy efficiencies of the proposed plant are determined to be 72.88% and 50.03% respectively.
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