Robust planning with multiple timescale dynamic adaptability for the green hydrogen ammonia synthesis system

Recent advances and challenges of electrochemical ammonia synthesis

Green agriculture enabled by versatile metal-organic frameworks: A review

Design and optimization of an ammonia synthesis system for ammonia-based solar thermochemical energy storage

Deep learning analysis of green ammonia synthesis: Evaluating techno-economic feasibility for sustainable production

Coal to methanol (CTM) is the most important source of methanol in China. However, the traditional CTM process needs to produce hydrogen through the water-gas shift (WGS) unit, which results in high CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> emissions. In this study, a new coal-to-methanol process coupled with green hydrogen (CTM <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">HPWE</inf> ) is proposed to reduce CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> emissions and improve energy efficiency. Compared with CTM process, the carbon utilization efficiency of CTM <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">HPWE</inf> process is increased by 76.75%, and the energy consumption and CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> emissions are reduced by 15.87% and 56.61% respectively. In a grid-powered mode, in which the hydrogen production system is powered by grid, the influence of electricity price and carbon tax on methanol cost is studied. When the renewable electricity price drops to 0.2427 yuan/kWh (the lowest bidding price for photovoltaic in China, 2020), the methanol cost of CTM <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">HPWE</inf> process will drop to 2565.75 yuan/t, equal to that of CTM process with medium level of carbon tax (240 yuan/tCO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ). In a wind-powered mode, in which the hydrogen production system is powered by self-built wind farm, through sizing optimization and dynamic operation management of wind-hydrogen system, the maximum wind power accommodation and stable methanol production are both realized under fluctuating wind power input. The economy of the optimized wind-hydrogen-methanol system is evaluated. The results shows that the methanol cost of CTM <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">HPWE</inf> process is 2245.53 RMB/t, which is comparable with CTM process under the domestic carbon tax reference value (51 RMB/tCO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ). Our study provides a feasible technical route for the upstream renewable energy accommodation coupled with downstream stable green hydrogen supply in the future.

Urea synthesis processes have been carried out at relatively high temperature (160–270 °C) and high pressure (120–250 bar). The use of high temperature and high pressure in urea synthesis is essential to increase production rate that would result in high profitability. New reaction method is proposed to produce the urea that requires lower pressure and temperature as compared to the conventional urea synthesis. This method is clean and green, used for the sustainable development that might change the landscape of future chemical processes. However, this is made possible due to the enhancement in nanotechnology where quantum mechanical understanding is called into play. New reactor designs are elaborated and discussed explicitly. Hematite nanocatalysts are used for this green urea synthesis process, in the presence of static and oscillating magnetic fields. Strategies to increase single to triplet conversion rate are performed for the better understanding on how to increase the urea rate of production. The focus on scrutinizing the greenhouse gas effect on the urea yield, in this case CO2 flow rate, is deliberated explicitly. The magnetic field strength and electromagnetic frequency are studied and empirically done for better understanding in singlet to triplet conversion. The highest urea yield of 17,472 ppm was obtained using a 1T static magnetic field, electromagnetic field of 5 GHz frequency, and 0.2 L/min CO2 flow rate. It is found that in the case of the pilot-scale reactor, urea yield has its optimum yield, 0.6 kg/hr, at 200 °C, 50 bar, and 3.25 GHz microwave frequency. This new method is a contender for urea and ammonia production that may change the landscape of chemical reaction in the future especially when zero carbon dioxide emission is required for the future sustainable development.

Ammonia, being a vital chemical compound, has made substantial contributions to the progress of society. It addresses not only the issue of nitrogen fixation from the atmosphere but also helps alleviate the food crisis. Nevertheless, the conventional Haber-Bosch process for synthesizing ammonia is frequently associated with substantial greenhouse gas emissions and the consumption of fossil fuels. Consequently, in response to significant environmental challenges, the prospective trajectory for the synthetic ammonia sector involves the adoption of strategies such as carbon reduction, energy-efficient conversions, and the exploration of environmentally friendly and sustainable approaches to ammonia synthesis. Among the various methods for green ammonia synthesis, chemical looping ammonia synthesis (CLAS) technology is regarded as one of the most promising alternatives to conventional ammonia synthesis methods in the upcoming years. This can be attributed to the relatively mild operating conditions and the flexible and distributed characteristics of its processes. In this paper, the thermodynamic and kinetic properties of nitridation and ammoniation reactions were examined through the lens of CLAS. The design and regulation strategies of nitrogen carriers (NCs) are summarized based on various types of NCs. The process of CLAS was summarized in relation to various NCs. This paper serves as a foundational resource for the prospective advancement of the CLAS framework.

This preliminary work opens a possible innovative route to investigating a paradigm shift in ammonia synthesis. It involves a hydrogen donor molecule (HDM) to favor ammonia synthesis at low pressure and temperature (1 bar, T < 200 °C), subsequently reducing the environmental footprint of NH3 synthesis.

Electrocatalytic nitrate reduction (NO3-R) offers a dual advantage by facilitating green ammonia synthesis while providing a sustainable strategy for the remediation of nitrate-laden wastewater. However, the activation of nitrate remains a significant challenge. Herein, we engineered an atomically ordered Bi-Ni intermetallic electrocatalyst by exploiting the unique electronic properties arising from its pronounced p-d orbital hybridization. This approach substantially improves the activation of reactant species, modulates the adsorption behavior of intermediate products, and effectively inhibits the competing hydrogen evolution reaction (HER). The BiNi intermetallic achieves ammonia production with a Faradaic efficiency (FE) of 90% at ampere-level current density across a broad potential window and demonstrates robust stability over 300 h under an ultrahigh industrial current density (700 ± 100 mA cm-2). In situ FTIR and Raman spectroscopies elucidate the evolution of key intermediates (-NH2, *NH3) and accelerated water dissociation for active hydrogen (*H) provision. Density functional theory (DFT) calculations verify that strong p-d orbital hybridization narrows the p-d band center gap, thereby enhancing reactant adsorption/activation, as well as improving the superior electron-donating capability during NO3-R. Importantly, the BiNi intermetallic efficiently treats high-concentration nitrate-laden industrial wastewater, achieving pollutant abatement rates of 97.6% along with a conversion rate to NH4Cl of 94.5%. This work devises a cost-competitive and high-performance catalyst, achieving its engineering application in sustainable electrochemical ammonia synthesis and practical nitrate wastewater remediation.

Hydrogen plays a key role in reducing greenhouse gas emissions, enabling decarbonization of the energy, transport and industrial sectors. Its importance in the energy balance will increase for several reasons. Firstly, in the modern world there is a transition to carbon-free energy, which stimulates the use of hydrogen. Secondly, a balanced system based on renewable energy sources is important to ensure stability and reliability of energy supply. The purpose of the study is to study the prospects for hydrogen production for the transition to sustainable development of the Azerbaijani economy. During the study, research methods such as graphical analysis, comparison of blue and green hydrogen production scenarios, analysis and synthesis method, and dynamic comparison method were used. The results of the study showed that in order to transition to a hydrogen economy in Azerbaijan, it is preferable to start with the production of blue hydrogen. There is potential for this in the form of rich natural gas reserves (confirmed gas reserves are 2.6 trillion cubic meters). With the advent of new technologies and lower production costs, a transition to green hydrogen will be possible. For this purpose, the country has a technical potential for renewable energy sources amounting to 135 GW on land and 157 GW at sea. The conclusions are that in order to transition to a hydrogen economy in Azerbaijan, it is necessary to adopt a strategy for transitioning the economy to a hydrogen basis, developing infrastructure, attracting investments in the modernization of chemical enterprises, and switching public transport to the use of hydrogen.

The nitrogen and carbon footprints of ammonia synthesis in China based on life cycle assessment

A new type of hydraulic turbocharger energy recovery system was designed and applied in the decarbonisation process by propylene carbonate of a 100k tons ammonia synthesis system firstly in China. Compared with existing energy recovery devices, hydraulic turbocharger energy recovery system runs more smoothly, has lower failure rate, longer service life and greater comprehensive benefits due to its unique structure, simpler adjustment process and better adaptability to fluid fluctuation.

Opportunities for green hydrogen production in petroleum refining and ammonia synthesis industries in India

The shipping industry has reached a higher level of maturity in terms of its knowledge and awareness of decarbonization challenges. Carbon-free or carbon-neutralized green fuel, such as green hydrogen, green ammonia, and green methanol, are being widely discussed. However, little attention has paid to the green fuel pathway from renewable energy to shipping. This paper, therefore, provides a review of the production methods for green power (green hydrogen, green ammonia, and green methanol) and analyzes the potential of green fuel for application to shipping. The review shows that the potential production methods for green hydrogen, green ammonia, and green methanol for the shipping industry are (1) hydrogen production from seawater electrolysis using green power; (2) ammonia production from green hydrogen + Haber–Bosch process; and (3) methanol production from CO2 using green power. While the future of green fuel is bright, in the short term, the costs are expected to be higher than conventional fuel. Our recommendations are therefore as follows: improve green power production technology to reduce the production cost; develop electrochemical fuel production technology to increase the efficiency of green fuel production; and explore new technology. Strengthening the research and development of renewable energy and green fuel production technology and expanding fuel production capacity to ensure an adequate supply of low- and zero-emission marine fuel are important factors to achieve carbon reduction in shipping.

Integrating water electrolysis (WE) with lithium-mediated nitrogen reduction (Li-NRR) offers a sustainable route for green ammonia production by directly utilizing protons from water oxidation, eliminating reliance on grey or blue hydrogen. Here, polyoxometalates (POMs) function as electron-coupled proton buffers (ECPBs) to seamlessly link WE with Li-NRR in a three-compartment flow reactor comprising an aqueous anode, an organic cathode, and a gas feed chamber. POMs serve as proton shuttles while suppressing the competing hydrogen evolution reaction (HER), facilitating efficient ammonia synthesis. The addition of polymethyl methacrylate (PMMA) enhances catholyte hydrophobicity, mitigating water contamination. By optimizing ECPB concentration, a dynamic balance is achieved between lithium nitride intermediates (LiNxHy) formation and consumption, yielding ammonia at 573.7±5.2µg h⁻¹ cm⁻2 with a Faradaic efficiency of 54.2%. This design advances flow reactor technology by uniquely utilizing water oxidation as a direct proton source, bypassing conventional hydrogen oxidation methods. The use of POMs as proton shuttles establishes a new benchmark for green ammonia production, reinforcing its potential in sustainable chemistry.