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A new configuration of solar energy-driven integrated system for ammonia synthesis and power generation is proposed in this study. A detailed dynamic analysis is conducted on the designed system to investigate its performance under different radiation intensities. The solar heliostat field is integrated to generate steam that is provided to the steam Rankine cycle for power generation. The significant amount of power produced is fed to the PEM electrolyser for hydrogen production after covering the system requirements. A pressure swing adsorption system is integrated with the system that separates nitrogen from the air. The produced hydrogen and nitrogen are employed to the cascaded ammonia production system to establish increased fractional conversions. Numerous parametric studies are conducted to investigate the significant parameters namely; incoming beam irradiance, power production using steam Rankine cycle, hydrogen and ammonia production and power production using TEGs and ORC. The maximum hydrogen and ammonia production flowrates are revealed in June for 17th hour as 5.85 mol/s and 1.38 mol/s and the maximum energetic and exergetic efficiencies are depicted by the month of November as 25.4% and 28.6% respectively. Moreover, the key findings using the comprehensive dynamic analysis are presented and discussed. • A new solar energy driven integrated system for ammonia synthesis is proposed. • A detailed modelling is conducted on the solar-assisted cascaded ammonia synthesis. • The additional heat from ammonia synthesis is recovered using thermoelectric generators. • Maximum H 2 and NH 3 flowrates are found in 17th hour of June as 5.85 and 1.38 mol/s. • Maximum energetic and exergetic efficiencies are found in Nov as 25.4% and 28.6%. [ABSTRACT FROM AUTHOR]

A novel configuration of hybrid wind-solar PV based cascaded ammonia synthesis is proposed in this article. A comprehensive dynamic analysis is conducted in this study which is substantial to explore the system functionality under different atmospheric conditions as the power achieved by the wind farm source is dependent on the wind speed and power extracted from the solar PV source depends upon solar radiation intensities. The system is designed to supply the electrical output extracted from the wind-solar PV sources to the proton exchange membrane electrolyser after meeting the system work requirements for hydrogen production. The produced hydrogen reacts with nitrogen separated from pressure swing adsorption to synthesize ammonia. A cascaded ammonia synthesis system is employed in this study to achieve high fractional conversion and simulated using Aspen Plus V11. Toronto is chosen as the geographical location for the dynamic simulation. The minimum exergetic efficiency is found to be 19.21% during the month of December and maximum exergetic efficiency is determined as 26.06% during the month of April. Similarly, the minimum energetic efficiency is found to be 18% during December and maximum energetic efficiency was determined as 24.42% during the month of April. In addition, the results obtained from comprehensive dynamic analyses are presented and discussed. • A novel hybrid wind-solar PV based cascaded ammonia synthesis is proposed. • A comprehensive dynamic analysis is conducted to explore the system functionality. • Toronto is chosen as the geographical location for dynamic simulations. • The maximum efficiency is determined for the month of April. [ABSTRACT FROM AUTHOR]

A novel idea of solar driven steam-autothermal hybrid reforming system (SAHRS) is proposed with onboard carbon capturing system in the existence of carbon emissions taxes. The CO 2 produced by the steam methane reforming is employed to the autothermal reforming as input and cryogenic air separation unit is integrated to provide autothermal reforming with oxygen and ammonia synthesis with nitrogen. The autothermal reforming is modified with further integration of water gas shift reactor (WGSR) which converts carbon mono-oxide into carbon dioxide by reacting with steam and this CO 2 is captured in the carbon capturing system using aqueous ammonia. Some amount of hydrogen produced by the autothermal reforming is employed to the ammonia synthesis reactor to achieve onboard ammonia for CO 2 capture. The system generates enough power to overcome the required power and supply power as a final commodity as well. The present system is essentially designed for cleaner production and industrial applications. The performance indicator for the designed system is defined in terms of energy and exergy efficiencies which are found to be 53.4% and 45.0% respectively. The carbon emissions produced by the system and tax saving by the aqueous ammonia based CO 2 capturing are also calculated in the proposed study. [ABSTRACT FROM AUTHOR]

• A biomass and solar energy based system is developed and comparatively evaluated. • The proposed system is analysed thermodynamically by energy and exergy approach. • Hydrogen, electricity, hot water for fish farming and cooling are major commodities. • The hydrogen production rate of 59.45 mol/s and power of 8.3 MW is produced. • The overall energy and exergy efficiencies are found to be 29.9% and 31.5%. A biomass and solar energy based system consisting of a gas turbine cycle, a reheat Rankine cycle, a solar heliostat field, four-step copper-chlorine cycle and absorption cooling system is newly proposed, analyzed and comparatively evaluated through energy and exergy approaches. The proposed system is designed for the multiple useful commodities of hydrogen, electricity, hot water for fish farming and cooling. The effects of different operating conditions and parameters, namely air flow rate, biomass flow rate, working fluid flow rate, direct normal irradiance, number of heliostats, evaporator exit temperature and ambient temperature are investigated for the performance of the designed system defined in terms of energy and exergy efficiencies, and energy and exergetic coefficients of performance. The combined system, excluding solar heliostat field and absorption cooling system, is simulated using the Aspen Plus while the subsystems are modeled using the engineering equation solver package. Heating and cooling are produced for community usage, and hydrogen can be employed for industrial purposes. Both design and cost analyses are also conducted using the Aspen Plus v9 and Aspen Plus economic analyzer v9. The energy efficiency of the overall system is determined as 29.9% while the corresponding exergy efficiency is obtained to be 31.5%. The additional findings and outcomes are also presented and discussed comprehensively. [ABSTRACT FROM AUTHOR]

A new integrated energy system employing the cement slag waste heat is uniquely proposed in this study. The core focus of the proposed system is to generate clean hydrogen thermochemically and convert it into ammonia. The designed system consists of the copper–chlorine (Cu–Cl) cycle, a cryogenic air separation unit and a steam Rankine cycle while the useful commodities produced by the proposed system are hydrogen, ammonia, oxygen, hot water and electricity. A CO 2 emission analysis is also conducted to calculate the emissions which can be avoided by recovering this waste heat. The Aspen Plus simulation software is utilized to model and simulate the proposed integrated system. A thermochemical water splitting process is incorporated into the system for hydrogen production. The cryogenic air separation unit is integrated in order to separate nitrogen from the air. This proposed system also reduces the environmental effects of the flue gas emitted by the cement industry. Multiple parametric studies are performed to investigate the system performance by varying operating conditions and state properties. The energy analysis is implemented on each component of the designed system. The overall energy efficiency of the system is concluded as 30.1%. The amount of CO 2 emissions which can be avoided by utilizing this waste heat is 29.64 ktonne/5 years. • A new integrated system employing the cement slag waste heat is uniquely proposed. • Ammonia, oxygen, hot water and electricity are the useful commodities of the system. • Four-step Cu–Cl cycle and cryogenic air separation unit are integrated for ammonia synthesis. • The overall energy efficiency of the system is concluded as 30.1%. • The CO 2 emissions avoided by the proposed integrated system are 29.64 ktonne/5 years. [ABSTRACT FROM AUTHOR]

Abstract This paper examines the performance and viability of a cement slag waste heat recovery system combined with a thermochemical copper-chlorine cycle for hydrogen production combined with hydrogen compression and a reheat Rankine cycle. The waste heat from the cement slag is recovered as a heat source for high-temperature reactions in the copper-chlorine cycle. The clean hydrogen production from waste heat recovery is examined with respect to both energy and exergy efficiencies. The integrated system is simulated and modeled in Aspen Plus. The multigeneration system utilizes the industrial waste heat and significantly reduces operating costs from the waste heat recovery. The overall energy efficiency of the integrated system is obtained as 32.5% while the corresponding exergy efficiency becomes 31.8%. Highlights • A new approach for clean hydrogen production via waste heat recovery. • Hydrogen and electricity are the two major outputs of the designed system. • The compressed H 2 production rate of the system is 19.6 mol/s. • The system overall energy and exergy efficiencies are 32.5% and 31.8%, respectively. [ABSTRACT FROM AUTHOR]

Abstract The thermochemical Cu Cl cycle has received greater attention by numerous researchers during the past decade as a promising hydrogen production method because of some operational advantages. The present paper analyzes three different configurations of the Cu Cl thermochemical cycle, namely three, four and five step ones thermodynamically. Some comparative parametric studies are conducted in order to investigate the overall energy and exergy efficiencies of the cycles considered. The Aspen plus is the software tool employed for the modeling and simulation of the cycles. The energy and exergy efficiencies of the five-step CuCl cycle are found to be 38.8% and 70.2% while the three-step CuCl cycle has an energy efficiency of 39.6% and an exergy efficiency of 68.1%, respectively. On the other hand, the four-step CuCl cycle provides the highest energy and exergy efficiencies of 41.9% and 75.7%. A parametric study is also conducted to investigate the effect of varying ambient temperature on the exergy efficiencies of all three cycles. The present study results further reveal that the cycle performance can be enhanced by improving the thermal management and reducing the exergy destructions. Highlights • Comparative assessment of the three different Cu Cl cycles for hydrogen production. • Numerous factors for heat and work requirements, operating conditions and exergy destructions are considered for analysis. • Aspen plus software tool is employed for the simulations of the cycles. • Four-step CuCl cycle offers the highest energy and exergy efficiencies. [ABSTRACT FROM AUTHOR]

Abstract A solar-wind hybrid trigeneration system is proposed and analyzed thermodynamically through energy and exergy approaches in this paper. Hydrogen, electricity and heat are the useful products generated by the hybrid system. The system consists of a solar heliostat field, a wind turbine and a thermochemical copper-chlorine (Cu-Cl) cycle for hydrogen production linked with a hydrogen compression system. A solar heliostat field is employed as a source of thermal energy while the wind turbine is used to generate electricity. Electric power harvested by the wind turbine is supplied to the electrolyzer and compressors and provides an additional excess of electricity. Hydrogen produced by the thermochemical copper-chlorine (Cu-Cl) cycle is compressed in a hydrogen compression system for storage purposes. Both Aspen Plus 9.0 and EES are employed as software tools for the system modeling and simulation. The system is designed to achieve high hydrogen production rate of 455.1 kg/h. The overall energy and exergy efficiencies of the hybrid system are 49% and 48.2%, respectively. Some additional results about the system performance are obtained, presented and discussed in the paper. Highlights • Analysis of a solar, wind and hydrogen hybrid trigeneration system. • A novel system of an integrated solar and wind source with the Cu-Cl cycle. • The three commodities of hydrogen, electricity and heat are produced. • Energy and exergy analyses are conducted for the integrated system. • The overall energy and exergy efficiencies are 49% and 48%, respectively. [ABSTRACT FROM AUTHOR]

A novel multi-generation integrated energy system is presented in this paper, consisting of a gas-steam combined cycle, four-step thermochemical copper-chlorine (Cu Cl) cycle, proton exchange membrane fuel cell (PEMFC) and a reverse osmosis (RO) desalination unit. Effective thermal management of waste heat is recognized as a key objective in the steel industry. Hydrogen, electricity, fresh water and heat are the useful outputs of the integrated system. The produced electricity supplies the electricity load required by the electrolyzer, compressor and pumps while the supplementary electricity is an additional system product. Aspen Plus and Engineering Equation Solver (EES) are used for modeling and simulation of the multi-generation system. The overall hydrogen production rate of the designed system is 51.8 kg/hr and the net power production is 1.7 MW. The overall energy efficiency of the multi-generation system is 63.3% and the exergy efficiency is 58.8%. Further sensitivity studies and outcomes are presented and discussed in this paper. [ABSTRACT FROM AUTHOR]

A novel integrated system for the production of hydrogen at a high pressure utilizing steel furnace waste heat is presented and analyzed in this paper. The system utilizes a hybrid thermochemical copper-chlorine (Cu-Cl) cycle. This study integrates the industrial waste heat source with the thermochemical Cu-Cl cycle combined with a hydrogen compression system. The electrical energy required by the system is provided by a supporting Rankine cycle. The hydrogen compression system compresses hydrogen to a pressure of 750 bars. The integrated system is simulated with Aspen Plus software. Energy and exergy analyses are performed for the integrated system. Results from the simulations are presented and discussed. The overall energy efficiency is 38.2% and overall exergy efficiency is found to be 39.8%. [ABSTRACT FROM AUTHOR]

• A new configuration of environmentally benign ammonia synthesis is proposed. • Three different natural gas reforming types are incorporated into designed system. • The system yields 10 mol/s of H 2 and 2.4 mol/s of NH 3. • The overall system energetic and exergetic efficiencies are found to be 66.83% and 68.55%. A new configuration to convert the traditional ammonia synthesis plants into an environmentally benign process is proposed in this study. The proposed design is implemented by integrating three different types of natural gas reforming for clean hydrogen, methanol and ammonia synthesis. The solar heat source provides the absorption cooling unit with heat and natural gas reformers with steam. The CO 2 emissions released by the natural gas reforming configuration reacts with hydrogen for methanol synthesis. A pressure swing adsorption unit separates oxygen for natural gas autothermal reforming and nitrogen for ammonia synthesis. A part of hydrogen produced by the natural gas reforming unit is designed to pass through a double-stage ammonia production reactor for ammonia synthesis. The proposed configuration yields 10 mol/s of H 2 and 2.4 mol/s of NH 3. The overall system energetic and exergetic efficiencies are found to be 66.83% and 68.55%. The present system yields 13.31 mol/s of CH 3 OH and 625.9 kW of cooling. Moreover, numerous sensitivity analyses are conducted on the proposed configuration and its performance assessment. [ABSTRACT FROM AUTHOR]

A new configuration of using hazardous industrial waste incineration system for energy generation and hydrogen production is proposed in this study. A heat recovery steam generator is used to generate steam for the double-stage Rankine cycle for electrical power generation. The additional heat from the incineration unit exhaust gas are employed to generate steam for the thermochemical Cu-Cl cycle. The CO 2 emissions carried by the incineration reactor exhaust gases are captured using aqueous ammonia-based carbon capturing system. The Aspen Plus V9 software is employed for the designed system simulation. Numerous sensitivity studies are undertaken to investigate each subsystem of the proposed hazardous industrial waste incineration system. The proposed system generates 7.08 MW of electrical output and hydrogen production flowrate of 12.6 kmol/h. The exergetic and energetic efficiencies of the designed system are found to be 43.3% and 39.1%. Furthermore, the sensitivity analysis results are presented and discussed. The incineration plants treating the waste and converting waste into energy can be substituted for conventional energy production and this proposed environmentally benign integrated system will resolve environmental problems by employing the hazardous industrial waste to the new configuration of the incineration process for producing hydrogen and power with zero CO 2 emissions. • The proposed incineration system produces H 2 and power with zero CO 2 emissions. • A heat recovery steam generator is used to generate steam for power generation. • Additional heat is employed to generate steam for thermochemical H 2 production. • An aqueous NH 3 based carbon capturing system is employed to capture CO 2 emissions. • The exergetic and energetic efficiencies are found to be 43.3% and 39.1%. [ABSTRACT FROM AUTHOR]

This paper focuses on a new configuration of biomass gasification based cascaded ammonia synthesis and proposes two different configurations of ammonia synthesis system using the Stoichiometric and Gibbs reactors in the Aspen Plus V11. A new heat recovery technique from biomass gasification using syngas cooling is also proposed in this study. The proposed configuration comprises of a biomass gasifier, a heat recovery unit for syngas cooling, a combined cycle, water gas shift reactor system (WGSRS), pressure swing adsorption (PSA) and ammonia production unit. The ammonia based carbon-capturing system is incorporated to ultimately capture the CO 2 emissions. The sensitivity analyses are conducted on each significant subsystem employed in the proposed configuration. The results obtained from the Gibbs reactors show that pressure has a positive effect while very high-temperature effects negative on the ammonia synthesis. The results also reveal that the cascaded ammonia synthesis offers high ammonia conversion rates. The designed system produces 21.9 kmol/h of ammonia and 3405 kW electrical power. The results obtained from the present sensitivity analysis are further presented and discussed. • New configuration of biomass gasification based cascaded NH 3 synthesis is proposed. • New heat recovery technique is proposed using the syngas cooling. • The designed system produces 21.9 kmol/h of ammonia and 3405 kW electrical power. • Overall exergy and energy efficiencies are found to 44.2% and 42.4% respectively. [ABSTRACT FROM AUTHOR]

Hydrogen is acknowledged as a potential fuel as it can be used as an energy carrier, a storage medium, in fuel cells and as a fuel as well and offers carbon-free solutions. This paper investigates three renewable energy based configurations for hydrogen production. The renewable energy sources considered in this study are solar PV, geothermal power generation and biomass gasification. The proposed study also presents a novel configuration of biomass gasification for hydrogen production via multistage water gas shift reactors. The solar PV and geothermal energy based hydrogen production systems are analysed employing the EES software while the hydrogen production system employing biomass gasification is simulated employing Aspen Plus. All three designed configurations are proceeded through numerous parametric analyses to investigate the system behavior and effect on system efficiencies. The hydrogen production using biomass gasification technique provides with the energetic and exergetic efficiencies of 53.6% and 49.8% and the efficiencies for the geothermal power generation based hydrogen production system are found to be 10.4% and 10.2% respectively. The exergetic and energetic efficiencies of hydrogen production system employing solar PV system are found to be 17.45% and 16.95%, respectively and the system is designed to produce 1.13 mol/s of hydrogen. Furthermore, the results of the parametric studies and sensitivity analyses are presented and discussed. • This paper investigates three renewable energy techniques for hydrogen production. • The considered renewable energy sources are solar PV, geothermal and biomass. • Biomass gasification offers energy and exergy efficiencies of 53.6% and 49.8%. • The energy and exergy efficiencies of geothermal hydrogen are 10.4% and 10.2%. • The exergy and energy efficiencies of solar PV based H 2 are 16.95% and 17.45%. [ABSTRACT FROM AUTHOR]

In this article, three different renewable energy methods are considered with wind, ocean thermal energy conversion (OTEC) and solar energy for clean hydrogen production, and Cu-Cl based thermochemical cycle is incorporated into systems to develop potential applications. In the proposed CuCl cycle configuration, the additional heat offered after the thermolysis reactor is recovered to heat the water before reaching the hydrolysis reactor. In the wind energy based hydrogen production system, the maximum exergy destruction rate is found to be 48.3 kW in the wind turbine. The turbine employed to the ocean thermal energy conversion system is found to be undergoing the highest exergy destruction rate of 143.3 kW. The energy and exergy efficiencies of the solar energy based thermochemical CuCl cycle are found to be 32.7% and 33.2% and the maximum exergy destruction rate of 350.69 kW is offered by the thermolysis reactor. The energetically improved configuration of the thermochemical CuCl cycle displays promising results compared to the earlier studies, such as lower heat requirements and higher efficiencies. The study indicates that there is a value to develop a clean OTEC based hydrogen production system and implement for practical applications. Furthermore, some sensitivity analyses are performed to investigate the performance of each system under different operating parameters and discussed. [ABSTRACT FROM AUTHOR]