Iran, Islamic Republic of
New Integrated Process for the Efficient Production of Methanol, Electrical Power, and Heating
Jan 2022
Publication
In this paper a novel process is developed to cogenerate 4741 kg/h of methanol 297.7 kW of electricity and 35.73 ton/h of hot water including a hydrogen purification system an absorption– compression refrigeration cycle (ACRC) a regenerative Organic Rankine Cycle (ORC) and parabolic solar troughs. The heat produced in the methanol reactor is recovered in the ORC and ACRC. Parabolic solar troughs provide thermal power to the methanol distillation tower. Thermal efficiencies of the integrated structure and the liquid methanol production cycle are 78.14% and 60.91% respectively. The process’s total exergy efficiency and irreversibility are 89.45% and 16.89 MW. The solar thermal collectors take the largest share of exergy destruction (34%) followed by heat exchangers (30%) and mixers (19%). Based on the sensitivity analysis D17 (mixture of H2 and low-pressure fuel gas before separation) was the most influential stream affecting the performance of the process. With the temperature decline of stream D17 from −139 to −149 °C the methanol production rate and the total thermal efficiency rose to 4741.2 kg/h and 61.02% respectively. Moreover the growth in the hydrogen content from 55% to 80% molar of the feed gas the flow rate of liquid methanol and the total exergy efficiency declined to 4487 kg/h and 86.05%.
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.
Exergy and Exergoeconomic Analysis of Hydrogen and Power Cogeneration Using an HTR Plant
Mar 2021
Publication
This paper proposes using sodium-cooled fast reactor technologies for use in hydrogen vapor methane (SMR) modification. Using three independent energy rings in the Russian BN-600 fast reactor steam is generated in one of the steam-generating cycles with a pressure of 13.1 MPa and a temperature of 505 °C. The reactor's second energy cycles can increase the gas-steam mixture's temperature to the required amount for efficient correction. The 620 ton/hr 540 °C steam generated in this cycle is sufficient to supply a high-temperature synthesis current source (700 °C) which raises the steam-gas mixture's temperature in the reactor. The proposed technology provides a high rate of hydrogen production (approximately 144.5 ton/hr of standard H2) also up to 25% of the original natural gas in line with existing SMR technology for preparing and heating steam and gas mixtures will be saved. Also exergy analysis results show that the plant's efficiency reaches 78.5% using HTR heat for combined hydrogen and power generation.
A Novel Exergy-based Assessment on a Multi-production Plant of Power, Heat and Hydrogen: Integration of Solid Oxide Fuel Cell, Solid Oxide Electrolyzer Cell and Rankine Steam Cycle
Feb 2021
Publication
Multi-production plant is an idea highlighting cost- and energy-saving purposes. However just integrating different sub-systems is not desired and the output and performance based on evaluation criteria must be assessed. In this study an integrated energy conversion system composed of solid oxide fuel cell (SOFC) solid oxide electrolyzer cell (SOEC) and Rankine steam cycle is proposed to develop a multi-production system of power heat and hydrogen to alleviate energy dissipation and to preserve the environment by utilizing and extracting the most possible products from the available energy source. With this regard natural gas and water are used to drive the SOEC and the Rankine steam cycle respectively. The required heat and power demand of the electrolyzer are designed to be provided by the fuel cell and the Rankine cycle. The feasibility of the designed integrated system is evaluated through comprehensive exergy-based analysis. The technical performance of the system is evaluated through exergy assessment and it is obtained that the SOFC and the SOEC can achieve to the high exergy efficiency of 84.8% and 63.7% respectively. The designed system provides 1.79 kg/h of hydrogen at 125 kPa. In addition the effective designed variables on the performance of the designed integrated system are monitored to optimize the system’s performance in terms of technical efficiency cost-effectivity and environmental considerations. This assessment shows that 59.4 kW of the available exergy is destructed in the combustion chamber. Besides the techno-economic analysis and exergoenvironmental assessment demonstrate the selected compressors should be re-designed to improve the cost-effectivity and decline the negative environmental impact of the designed integrated energy conversion system. In addition it is calculated that the SOEC has the highest total cost and also the highest negative impact on the environment compared to other designed units in the proposed integrated energy conversion system.
Improving Hydrogen Production Using Co-cultivation of Bacteria with Chlamydomonas Reinhardtii Microalga
Sep 2018
Publication
Hydrogen production by microalgae is a promising technology to achieve sustainable and clean energy. Among various photosynthetic microalgae able to produce hydrogen Chlamydomonas reinhardtii is a model organism widely used to study hydrogen production. Oxygen produced by photosynthesis activity of microalgae has an inhibitory effect on both expression and activity of hydrogenases which are responsible for hydrogen production. Chlamydomonas can reach anoxia and produce hydrogen at low light intensity. Here the effect of bacteria co-cultivation on hydrogen produced by Chlamydomonas at low light intensity was studied. Results indicated that however co-culturing Escherichia coli Pseudomonas stutzeri and Pseudomonas putida reduced the growth of Chlamydomonas it enhanced hydrogen production up to 24% 46% and 32% respectively due to higher respiration rate in the bioreactors at low light intensity. Chlamydomonas could grow properly in presence of an unknown bacterial consortium and hydrogen evolution improved up to 56% in these co-cultures.
On the Response of a Lean-premixed Hydrogen Combustor to Acoustic and Dissipative-dispersive Entropy Waves
May 2019
Publication
Combustion of hydrogen or hydrogen containing blends in gas turbines and industrial combustors can activate thermoacoustic combustion instabilities. Convective instabilities are an important and yet less investigated class of combustion instability that are caused by the so called “entropy waves”. As a major shortcoming the partial decay of these convective-diffusive waves in the post-flame region of combustors is still largely unexplored. This paper therefore presents an investigation of the annihilating effects due to hydrodynamics heat transfer and flow stretch upon the nozzle response. The classical compact analysis is first extended to include the decay of entropy waves and heat transfer from the nozzle. Amplitudes and phase shifts of the responding acoustical waves are then calculated for subcritical and supercritical nozzles subject to acoustic and entropic forcing. A relation for the stretch of entropy wave in the nozzle is subsequently developed. It is shown that heat transfer and hydrodynamic decay can impart considerable effects on the entropic response of the nozzle. It is further shown that the flow stretching effects are strongly frequency dependent. The results indicate that dissipation and dispersion of entropy waves can significantly influence their conversion to sound and therefore should be included in the entropy wave models.
Modeling of Thermal Performance of a Commercial Alkaline Electrolyzer Supplied with Various Electrical Currents
Nov 2021
Publication
Hydrogen produced by solar and other clean energy sources is an essential alternative to fossil fuels. In this study a commercial alkaline electrolyzer with different cell numbers and electrode areas are simulated for different pressure temperature thermal resistance and electrical current. This alkaline electrolyzer is considered unsteady in simulations and different parameters such as temperature are obtained in terms of time. The obtained results are compared with similar results in the literature and good agreement is observed. Various characteristics of this alkaline electrolyzer as thermoneutral voltage faraday efficiency and cell voltage are calculated and displayed. The outlet heat rate and generated heat rate are obtained as well. The pressure and the temperature in the simulations are between 1 and 100 bar and between 300 and 360 Kelvin respectively. The results show that the equilibrium temperature is reached 2-3 hours after the time when the Alkaline electrolyzer starts to work.
A Thorough Economic Evaluation by Implementing Solar/Wind Energies for Hydrogen Production: A Case Study
Jan 2022
Publication
A technical–economic assessment was carried out in this study to determine the possibilities for wind and solar power generation in Afghanistan’s Helmand province. The results showed that most of the province has a solar irradiance of over 400 W/m2 and also showed that wind and solar power generated in the province can be up to twice as cheap as the official price of renewable power in Afghanistan. The most suitable site for solar and hydrogen production was found to be Laškar Gah where solar and hydrogen can be produced at a cost of 0.066 $/kWh and 2.1496 $/kg-H ¯ 2 respectively. In terms of wind power production and hydrogen production from wind the most suitable site was Sang¯ın where wind power and hydrogen could be produced at costs of 0.057 $/kWh and 1.4527 $/kg-H2 respectively. Despite the high potential of wind and solar energy in the Helmand province the most suitable place in this region to produce hydrogen from wind/solar energy was evaluated from technical economic and environmental perspectives with the Multi-Criteria DecisionMaking (MCDM) method. The Stepwise Weight Assessment Ratio Analysis (SWARA) method was used for weighting criteria and the Weighted Aggregated Sum Product Assessment (WASPAS) method was used to prioritize locations. The results show that Sang¯ın is the most suitable place for the construction of a wind hydrogen power plant and Laškar Gah is the most suitable place for the ¯ construction of a solar hydrogen power plant.
Optimization of Geothermal- and Solar-driven Clean Electricity and Hydrogen Production Multi-generation Systems to Address the Energy Nexus
Jan 2022
Publication
Given the limited sources of fossil fuels mankind should find new ways to meet its energy demands. In this regard geothermal and solar energy are acknowledged as reliable safe promising and clean means for this purpose. In this research study a comparative analysis is applied on geothermal and solar-driven multi-generation systems for clean electricity and hydrogen production through energy and exergy assessments. The system consists of an organic Rankine cycle a proton electrolyte membrane electrolyzer and a thermoelectric generator subsystem. The Engineering Equation Solver software has been utilized in order to model the system and obtain the output contours sensitivity analysis and exergy destruction. The results were calculated considering the ambient temperature of Bandar Abbas city as a case study considering the geothermal system due to better performance in comparison to the solar system. According to the sensitivity analysis the turbine efficiency evaporator inlet temperature thermoelectric generator suitability criterion pump efficiency and evaporator inlet mass flow rate are the most influential parameters. Also the exergy analysis showed that the utmost system's exergy destruction is pertinent to the evaporator and the least is related to the pump. In addition the system produces 352816 kWh and 174.913 kg of electrical power and hydrogen during one year.
Improved Monitoring and Diagnosis of Transformer Solid Insulation Using Pertinent Chemical Indicators
Jul 2021
Publication
Transformers are generally considered to be the costliest assets in a power network. The lifetime of a transformer is mainly attributable to the condition of its solid insulation which in turn is measured and described according to the degree of polymerization (DP) of the cellulose. Since the determination of the DP index is complex and time-consuming and requires the transformer to be taken out of service utilities prefer indirect and non-invasive methods of determining the DP based on the byproduct of cellulose aging. This paper analyzes solid insulation degradation by measuring the furan concentration recently introduced methanol and dissolved gases like carbon oxides and hydrogen in the insulating oil. A group of service-aged distribution transformers were selected for practical investigation based on oil samples and different kinds of tests. Based on the maintenance and planning strategy of the power utility and a weighted combination of measured chemical indicators a neural network was also developed to categorize the state of the transformer in certain classes. The method proved to be able to improve the diagnostic capability of chemical indicators thus providing power utilities with more reliable maintenance tools and avoiding catastrophic failure of transformers.
Ranking Locations for Hydrogen Production Using Hybrid Wind-Solar: A Case Study
Apr 2021
Publication
Observing the growing energy demand of modern societies many countries have recognized energy security as a looming problem and renewable energies as a solution to this issue. Renewable hydrogen production is an excellent method for the storage and transfer of energy generated by intermittent renewable sources such as wind and solar so that they can be used at a place and time of our choosing. In this study the suitability of 15 cities in Fars province Iran for renewable hydrogen production was investigated and compared by the use of multiple multi-criteria decision-making methods including ARAS SAW CODAS and TOPSIS. The obtained rankings were aggregated by rank averaging Borda method and Copeland method. Finally the partially ordered set ranking technique was used to reach a general consensus about the ranking. The criteria that affect hydrogen production were found to be solar energy potential wind energy potential population air temperature natural disasters altitude relative humidity land cost skilled labor infrastructure topographic condition and distance from main roads. These criteria were weighted using the best–worst method (BWM) based on the data collected by a questionnaire. Solar energy potential was estimated using the Angstrom model. Wind energy potential was estimated by using the Weibull distribution function for each month independently. The results of the multi-criteria decision-making methods showed Izadkhast to be the most suitable location for renewable hydrogen production in the studied area.
Comprehensive Study on Hydrogen Production via Propane Steam Reforming Inside a Reactor
Feb 2021
Publication
In the proton exchange membrane fuel cells the required hydrogen must be produced in some way. The power generators in the path of these fuel cells generally include a steam reactor that through other fuels provides the needed energy to produce hydrogen. This study investigates a steam reactor powered by propane fuel consisting of a shell and tube heat exchanger. The shell contains a catalyst that receives the mixture of propane and steam and the tubes embedded inside the reformer contain hot gases that provide a suitable substrate for the reaction. Velocity and temperature fields inside the reformer species concentration control and reaction rate are studied. The conversion of reactants and yield of products are investigated according to the reaction rate. The results show that the hydrogen production yield can vary from 77.5 % to 92.2 %. The reaction rate can be controlled by the velocity and temperatures of the hot gases. However for the T=900 K full propane consumption is achieved at the reformer outlet.
Effect of Hydrogen on the Tensile Behavior of Austenitic Stainless Steels 316L Produced by Laser-Powder Bed Fusion
Apr 2021
Publication
Hydrogen was doped in austenitic stainless steel (ASS) 316L tensile samples produced by the laser-powder bed fusion (L-PBF) technique. For this aim an electrochemical method was conducted under a high current density of 100 mA/cm2 for three days to examine its sustainability under extreme hydrogen environments at ambient temperatures. The chemical composition of the starting powders contained a high amount of Ni approximately 12.9 wt.% as a strong austenite stabilizer. The tensile tests disclosed that hydrogen charging caused a minor reduction in the elongation to failure (approximately 3.5% on average) and ultimate tensile strength (UTS; approximately 2.1% on average) of the samples using a low strain rate of 1.2 × 10−4 s−1. It was also found that an increase in the strain rate from 1.2 × 10−4 s−1 o 4.8 ×10−4 s−1 led to a reduction of approximately 3.6% on average for the elongation to failure and 1.7% on average for UTS in the pre-charged samples. No trace of martensite was detected in the X-ray diffraction (XRD) analysis of the fractured samples thanks to the high Ni content which caused a minor reduction in UTS × uniform elongation (UE) (GPa%) after the H charging. Considerable surface tearing was observed for the pre-charged sample after the tensile deformation. Additionally some cracks were observed to be independent of the melt pool boundaries indicating that such boundaries cannot necessarily act as a suitable area for the crack propagation.
Energy, Exergy, and Economic Analysis of Cryogenic Distillation and Chemical Scrubbing for Biogas Upgrading and Hydrogen Production
Mar 2022
Publication
Biogas is one of the most important sources of renewable energy and hydrogen production which needs upgrading to be functional. In this study two methods of biogas upgrading from organic parts of municipal waste were investigated. For biogas upgrading this article used a 3E analysis and simulated cryogenic separation and chemical scrubbing. The primary goal was to compare thermoeconomic indices and create hydrogen by reforming biomethane. The exergy analysis revealed that the compressor of the refrigerant and recovery column of MEA contributed the most exergy loss in the cryogenic separation and chemical scrubbing. The total exergy efficiency of cryogenic separation and chemical scrubbing was 85% and 84%. The energy analysis revealed a 2.07% lower energy efficiency for chemical scrubbing. The capital energy and total annual costs of chemical absorption were 56.51 26.33 and 54.44 percent lower than those of cryogenic separation respectively indicating that this technology is more economically feasible. Moreover because the thermodynamic efficiencies of the two methods were comparable the chemical absorption method was adopted for hydrogen production. The biomethane steam reforming was simulated and the results indicated that this method required an energy consumption of 90.48 MJ kgH2 . The hydrogen production intensity equaled 1.98 kmoleH2 kmolebiogas via a 79.92% methane conversion.
Impact of Local Emergency Demand Response Programs on the Operation of Electricity and Gas Systems
Mar 2022
Publication
With increasing attention to climate change the penetration level of renewable energy sources (RES) in the electricity network is increasing. Due to the intermittency of RES gas‐fired power plants could play a significant role in backing up the RES in order to maintain the supply– demand balance. As a result the interaction between gas and power networks are significantly in‐ creasing. On the other hand due to the increase in peak demand (e.g. electrification of heat) net‐ work operators are willing to execute demand response programs (DRPs) to improve congestion management and reduce costs. In this context modeling and optimal implementation of DRPs in proportion to the demand is one of the main issues for gas and power network operators. In this paper an emergency demand response program (EDRP) is implemented locally to reduce the con‐ gestion of transmission lines and gas pipelines more efficiently. Additionally the effects of optimal implementation of local emergency demand response program (LEDRP) in gas and power networks using linear and non‐linear economic models (power exponential and logarithmic) for EDRP in terms of cost and line congestion and risk of unserved demand are investigated. The most reliable demand response model is the approach that has the least difference between the estimated demand and the actual demand. Furthermore the role of the LEDRP in the case of hydrogen injection instead of natural gas in the gas infrastructure is investigated. The optimal incentives for each bus or node are determined based on the power transfer distribution factor gas transfer distribution factor available electricity or gas transmission capability and combination of unit commitment with the LEDRP in the integrated operation of these networks. According to the results implementing the LEDRP in gas and power networks reduces the total operation cost up to 11% and could facilitate hydrogen injection to the network. The proposed hybrid model is implemented on a 24‐bus IEEE electricity network and a 15‐bus gas network to quantify the role and value of different LEDRP models.
Hydrogen Fuel and Electricity Generation from a New Hybrid Energy System Based on Wind and Solar Energies and Alkaline Fuel Cell
Apr 2021
Publication
Excessive consumption of fossil fuels has led to depletion of reserves and environmental crises. Therefore turning to clean energy sources is essential. However these energy sources are intermittent in nature and have problems meeting long-term energy demand. The option suggested by the researchers is to use hybrid energy systems. The aim of this paper is provide the conceptual configuration of a novel energy cycle based on clean energy resources. The novel energy cycle is composed of a wind turbine solar photovoltaic field (PV) an alkaline fuel cell (AFC) a Stirling engine and an electrolyzer. Solar PV and wind turbine convert solar light energy and wind kinetic energy into electricity respectively. Then the generated electricity is fed to water electrolyzer. The electrolyzer decomposes water into oxygen and hydrogen gases by receiving electrical power. So the fuel cell inlets are provided. Next the AFC converts the chemical energy contained in hydrogen into electricity during electrochemical reactions with by-product (heat). The purpose of the introduced cycle is to generate electricity and hydrogen fuel. The relationships defined for the components of the proposed cycle are novel and is examined for the first time. Results showed that the output of the introduced cycle is 10.5 kW of electricity and its electrical efficiency is 56.9%. In addition the electrolyzer uses 9.9 kW of electricity to produce 221.3 grams per hour of hydrogen fuel. The share of the Stirling engine in the output power of the cycle is 9.85% (1033.7 W) which is obtained from the dissipated heat of the fuel cell. In addition wind turbine is capable of generating an average of 4.1 kW of electricity. However 238.6 kW of cycle exergy is destroyed. Two different scenarios are presented for solar field design.
Evaluation of a New Combined Energy System Performance to Produce Electricity and Hydrogen with Energy Storage Option
Mar 2021
Publication
According to new findings the use of alternative energy sources such as wind energy is needed to supply the energy demand of future generations. On the other hand combined renewable energy systems can be more efficient than their stand-alone systems. Therefore clean energy-based hybrid energy systems can be a suitable solution for fossil fuels. However for their widespread commercialization more detailed and powerful studies are needed. On the other hand in order to attain sustainable development for the use of renewable energy sources due to their nature energy storage is required. The motivation of this study is introduce and examine a new energy system performance for the production of electricity and hydrogen fuel as well as energy storage. So this paper presents the energy and exergy operation of a hybrid wind turbine water electrolyzer and Pumped-hydro-compressed air system. The electricity produced by the wind turbine is used to produce hydrogen fuel in electrolyzer and the excess energy is stored using the storage system. It was found that the electrolyzer needed 512.6 W of electricity to generate 5 mol/h of hydrogen fuel which was supplied by a 10 kW-wind turbine. In such a context the efficiency of the process was 74.93%. Furthermore on average the isothermal process requires 17.53% less storage capacity than the isentropic process. The effect of key parameters such as rate of hydrogen fuel production operating pressures wind speed and components efficiency on the process operation is also examined.
The Role of Clean Hydrogen Value Chain in a Successful Energy Transition of Japan
Aug 2022
Publication
The clean hydrogen in the prioritized value chain platform could provide energy incentives and reduce environmental impacts. In the current study strengths weaknesses opportunities and threats (SWOT) analysis has been successfully applied to the clean hydrogen value chain in different sectors to determine Japan’s clean hydrogen value chain’s strengths weaknesses opportunities and threats as a case study. Japan was chosen as a case study since we believe that it is the only pioneer country in that chain with a national strategy investments and current projects which make it unique in this way. The analyses include evaluations of clean energy development power supply chains regional energy planning and renewable energy development including the internal and external elements that may influence the growth of the hydrogen economy in Japan. The ability of Japan to produce and use large quantities of clean hydrogen at a price that is competitive with fossil fuels is critical to the country’s future success. The implementation of an efficient carbon tax and carbon pricing is also necessary for cost parity. There will be an increasing demand for global policy coordination and inter-industry cooperation. The results obtained from this research will be a suitable model for other countries to be aware of the strengths weaknesses opportunities and threats in this field in order to make proper decisions according to their infrastructures potentials economies and socio-political states in that field.
Solid Air Hydrogen Liquefaction, the Missing Link of the Hydrogen Economy
Mar 2023
Publication
The most challenging aspect of developing a green hydrogen economy is long-distance oceanic transportation. Hydrogen liquefaction is a transportation alternative. However the cost and energy consumption for liquefaction is currently prohibitively high creating a major barrier to hydrogen supply chains. This paper proposes using solid nitrogen or oxygen as a medium for recycling cold energy across the hydrogen liquefaction supply chain. When a liquid hydrogen (LH2) carrier reaches its destination the regasification process of the hydrogen produces solid nitrogen or oxygen. The solid nitrogen or oxygen is then transported in the LH2 carrier back to the hydrogen liquefaction facility and used to reduce the energy consumption cooling gaseous hydrogen. As a result the energy required to liquefy hydrogen can be reduced by 25.4% using N2 and 27.3% using O2. Solid air hydrogen liquefaction (SAHL) can be the missing link for implementing a global hydrogen economy.
Just Energy Transition: Learning from the Past for a More Just and Sustainable Hydrogen Transition in West Africa
Dec 2022
Publication
The rising demand for energy and the aim of moving away from fossil fuels and to low-carbon power have led many countries to move to alternative sources including solar energy wind geothermal energy biomass and hydrogen. Hydrogen is often considered a “missing link” in guaranteeing the energy transition providing storage and covering the volatility and intermittency of renewable energy generation. However due to potential injustice with regard to the distribution of risks benefits and costs (i.e. in regard to competing for land use) the large-scale deployment of hydrogen is a contested policy issue. This paper draws from a historical analysis of past energy projects to contribute to a more informed policy-making process toward a more just transition to the hydrogen economy. We perform a systematic literature review to identify relevant conflict factors that can influence the outcome of hydrogen energy transition projects in selected Economic Community of West African States countries namely Nigeria and Mali. To better address potential challenges policymakers must not only facilitate technology development access and market structures for hydrogen energy policies but also focus on energy access to affected communities. Further research should monitor hydrogen implementation with a special focus on societal impacts in producing countries.
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