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Electrochemical Nitrogen Reduction Application of Atomically Dispersed Metallic Materials
Published in Wei Yan, Xifei Li, Shuhui Sun, Xueliang Sun, Jiujun Zhang, Atomically Dispersed Metallic Materials for Electrochemical Energy Technologies, 2023
Revanasiddappa Manjunatha, Shuqi Deng, Ejikeme Raphael Ezeigwe, Wei Yan, Jiujun Zhang, Li Dong
Currently, the most common process for industrial-scale ammonia production is the Haber–Bosch process. Based on the catalytic synthesis of ammonia from pure nitrogen and hydrogen at high pressures (150–300 atm) and temperatures (400°C–500°C), the Haber–Bosch process uses iron and ruthenium (the latter is used in the Kellogg Advanced Ammonia Process) as catalysts.5 The reaction of ammonia synthesis is entirely controlled by the equilibrium, which can be shifted under high pressure in the direction of product formation in accordance with Le Chatelier’s principle. Although the thermochemistry suggests that the reactor should be externally cooled, the high activation energy barrier for the dissociation of nitrogen molecules (E(N≡N) = 941 kJ mol−1) dictates the need for high operating temperatures.6 Most of the hydrogen generated in the Haber–Bosch procedure is produced by using methane steam reformation, the only products of which are hydrogen and CO2. This places the Haber–Bosch method of ammonia synthesis at the top of the list of industrial fabrication processes directly responsible for the emission of greenhouse gases.7 Therefore, novel electrocatalysts are required for the efficient and “green” electrosynthesis of ammonia directly from nitrogen (or air as a nitrogen source) and water (i.e., a source of protons).
Optimization of regasified liquefied natural gas based reforming process for syngas production in an ammonia plant
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Anju Sunny, N. Gazliya, K. Aparna
Ammonia production is based on the Haber-Bosch process in which nitrogen and hydrogen involved with a ratio of 1:3. For ammonia production, the required nitrogen is obtained from the air, and the hydrogen is from a variety of sources such as natural gas, oil refining products such as naphtha, residual oils, coal, etc. Finding potential sources of raw material for getting hydrogen has become a crucial challenge recently. Nowadays, increase in the environmental pollution and reduction in the availability of fossil fuels forced industry persons to look for reliable raw material for obtaining hydrogen. As a solution to the above-discussed problems, regasified liquefied natural gas (R-LNG) has been introduced as a suitable feed for ammonia production for getting the required hydrogen (Sunny, Solomon, and Aparna 2016).
Technoeconomic evaluation of offshore green ammonia production using tidal and wind energy: a case study
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Honora Driscoll, Nicholas Salmon, Rene Bañares-Alcántara
Ammonia (NH3), primarily used for fertilizers, is conventionally produced from fossil fuels (brown ammonia). In particular, 72% of ammonia is currently produced from natural gas (gray ammonia) and 22% from coal (black ammonia) (IRENA 2022). The scale and impact of ammonia production is vast – ammonia is the second most produced chemical in the world and accounts for 1% of global greenhouse emissions (IRENA 2022). Ammonia’s uses are rapidly expanding from fertilizer and explosives production to use as an energy storage vector, as a hydrogen carrier, for power generation and as a maritime fuel.
An overview of selected emerging outdoor airborne pollutants and air quality issues: The need to reduce uncertainty about environmental and human impacts
Published in Journal of the Air & Waste Management Association, 2020
As of 2014, about 88% of the ammonia produced worldwide was used as fertilizers. Worldwide production of NH3 is on the rise as shown in Figure 2. Roughly 60–85% of NH3 emissions in the United States are estimated to be associated from agricultural sources. Half of the industrial ammonia production is eventually lost to the environment with significant impacts on ecosystems (Erisman et al. 2007; Höpfner et al. 2016). Note, however, that part of the ammonia atmospheric gaseous current rise is associated with the decrease of the main reactive agents (NOx and SO2). Satellite observations suggest a significant increase of about 30% in tropospheric gas-phase NH3 in North China during 2008–2016. However, the estimated NH3 emissions decreased slightly by 7% in the same area (mostly due to changes in agricultural practices). During the same time, emissions of SO2 have rapidly declined by about 60% during the same time. By integrating measurements from ground and satellite, a long-term anthropogenic NH3 emission inventory, and chemical transport model simulations, Liu et al. (2018) found that large SO2 emission reduction is responsible for the NH3 increase over the North China Plain (due to less ammonium sulfate formation). Similarly, Chan, Gantt, and McDow (2018) have shown that the reduction of sulfates have produced a switch to winter PM2.5 concentration maxima in the United States now dominated by nitrate aerosols (instead of sulfates). This illustrates the difficulty of managing air quality since reducing a regulated pollutant can produce another one to emerge and produce new kinds of problem. That also suggests that no single strategy will work to reduce the adverse impact of excess nitrogen in the environment.