Ammonia System Research Articles

Validation of a sensor system for the measurement of breath ammonia using selected-ion flow-tube mass spectrometry.

The measurement of trace breath gases is of growing interest for its potential to provide non-invasive physiological information in health and disease. While instrumental techniques such as selected-ion flow-tube mass spectrometry (SIFT-MS) can achieve this, these are less suitable for clinical application. Sensitive sensor-based systems for breath ammonia could be more widely deployed, but have proven challenging to develop. This work demonstrates the sequential analytical validation of an electrochemical impedance-based sensor system for the measurement of ammonia in breath using SIFT-MS. Qualitative and relative responses between the two methods were comparable, although there were consistent differences in absolute concentration. When tested in artificial breath ammonia, sensors had a relative impedance sensitivity of 3.43x10-5ppbv-1for each breath in the range of 249 to 1,653 ppbv (r2=0.87,p<0.05). When correlated with SIFT-MS using human breath (n=14), ammonia was detected in the range of 100 to 700 ppbv (r=0.78,p<0.001), demonstrating acceptable sensitivity, reproducibility and dynamic range for clinical application.

Pump-Free Pneumatic Actuator Driven by the Vapor Pressure at the Gas-Liquid Equilibrium of Aqua Ammonia.

Currently, pneumatic soft actuators are widely used due to their impressive adaptability, but they still face challenges for more extensive practical applications. One of the primary issues is the bulky and noisy air compressors required to generate air pressure. To circumvent this critical problem, this work proposes a new type of air pressure source, based on the vapor pressure at the gas-liquid equilibrium to replace conventional air pumps. Compared with the previous phase transition method, this approach gains advantages such as generating gas even at low temperatures (instead of boiling point), more controllable gas output, and higher force density (since both ammonia and water contribute to the gas pressure). This work built mathematical models to explain the mechanism of converting energy to output action force from electrical energy and found the aqua ammonia system is one of the optimal choices. Multiple prototypes were created to demonstrate the capability of this method, including a pouch actuator that pushed a load 20,555 times heavier than its dead weight. Finally, based on the soft actuator, an untethered crawling robot was implemented with onboard batteries, showing the potentially extensive applications of this methodology.

Smartphone based TLC approach versus conventional densitometric measurement for the simultaneous determination of donepezil and memantine, content uniformity testing along with greenness and whiteness assessment

Thin layer chromatography (TLC) is a straightforward and economical technique that plays a major role in analytical field. Introducing the amenities of smartphones as accessible alternative detectors to TLC separation methods elaborates the cost-effectiveness of this technique and supports the appropriate assay of various aliphatic compounds after visualization by suitable reagents. Herein, two TLC coupled with smartphone's camera approaches are proposed for the assay of donepezil hydrochloride (DON) and memantine hydrochloride (MEM), a combined medication used in the management of Alzheimer's disease. Separation was achieved using a developing system of ethyl acetate, methanol, toluene, and ammonia (33%, w/v) in a ratio of 4:1:4:0.2, by volume. The dried plates were scanned at 190 nm for the densitometric assay, then visualized with modified Dragendorff's reagent and photographed by smartphone's camera. The data were integrated by displaying the photos in either ImageJ software or Color-Picker application. The findings produced from the three detection approaches were contrasted over concentration ranges of 1–18 & 4–28 μg/spot for the densitometric method, while the range was 1–20 & 1–30 μg/spot for the ImageJ method and 3–18 & 2–20 μg/spot for the Color-Picker method for DON and MEM, respectively. The methods were suitable for assaying both drugs in their pure form and combined pharmaceutical formulations. Densitometric and ImageJ-based methods were applied to evaluate the dosage forms content uniformity. The developed methods were assessed by three metric tools for greenness and sustainability, namely Green Analytical Procedure Index, Analytical GREEnness Metric Approach, and White Analytical Chemistry.

Thermodynamic and Economic Analysis of the Green Ammonia Synthesis System Driven by Synergistic Hydrogen Production Using Alkaline Water Electrolyzers and Proton Exchange Membrane Electrolyzers

Green ammonia and hydrogen from renewable energy sources have emerged as crucial players during the transition of the chemical industry from a fossil energy‐dominated economy to one that is environmentally friendly. This work proposes a green ammonia synthesis system driven by synergistic hydrogen generation using alkaline water electrolyzers (AWE) and proton exchange membrane electrolyzers (PEMEC). The effects of hydrogen‐production ratios of PEMEC and AWE on the thermodynamic and economic performance of the system are compared and analyzed via multi‐objective optimization. The findings showed that an increase in the amount of hydrogen produced by PEMEC improves the system's energy efficiency, but the payback period is delayed because of the PEMEC high initial investment cost. The techno‐economic performance of the system at a 1:1 ratio of PEMEC to AWE hydrogen production are investigated considering the system level heat integration based on the pinch point analysis method to maximize the heat recovery. The results show that increasing the operational temperature, the pressure of the electrolyzer, and the ammonia synthesis pressure will enhance the system's thermal performance. Economic analysis shows that reducing electricity prices and electrolyzer investment costs will be the key to achieving the economic feasibility of the green ammonia system.

Large Eddy Simulation of Ammonia-Hydrogen Non-Premixed Flames Stabilized on a Bluff Body Burner

Abstract The demand for carbon-free fuels such as NH3 and H2 has been growing due to stricter environmental policies on carbon emissions. Since ammonia is easier to store and transport, it is considered an alternative fuel for marine, aviation, and gas turbine industries. However, the narrow flammability, low reactivity, and potential emissions of NOx are important challenges that need to be overcome if ammonia is to be used as a practical fuel for industrial use. Recent works have provided experimental data on the characteristics of NH3 flames under premixed and non-premixed combustion, focusing on flame speed, turbulence-chemistry interaction, and especially the dissociation/cracking of NH3 into H2 and N2. These measurements have encouraged the use of CFD for the simulation and scaling of practical ammonia systems, evaluating the performance of different numerical models for NH3 combustion. In this study, LES is utilized to predict a series of NH3/H2/N2 non-premixed flames stabilized on a bluff body burner. The accuracy of the FGM combustion model combined with LES has been examined, using a commercial CFD solver. The different cracking levels of NH3 into H2 and N2 lead to simulation cases ranging from an H2/N2 flame (i.e., “fully cracked”), to a flame with 50% NH3 (i.e., “half cracked”). The different flame shapes, temperature distributions, and NOx emissions have been simulated, generally matching well experimental data. The developed numerical settings and workflows may be applied to simulating more complex combustors which use NH3 as a fuel.

Silver recovery from silicon solar cells waste by hydrometallurgical and electrochemical technique

In this study, hydrometallurgical and electrochemical methods were combined to achieve an innovative strategy for the effective recovery of the finest silver metal from silicon solar waste. The waste was thoroughly characterized by X-Ray diffraction, Scanning Electron Microscopy, X-Ray Absorption Spectroscopy, and Inductively Coupled Plasma Optical Emission Spectroscopy. A chemometric approach based on experimental design was used to find the best conditions for the leaching process based on a combined base-activated persulfate and ammonia system while a novel method known as electrodeposition-redox replacement was used to recover it. A remarkable pure silver recovery of 98.7±1.4 % was achieved. Additionally, Scanning Electron Microscopy analysis confirmed the enrichment of Ag particles on the electrode. Overall, these promising results showed how flexible the electrodeposition-redox replacement approach is in producing a range of valuable functional materials from intricate hydrometallurgical solutions including multiple metal impurities.

Novel integrated system for power, hydrogen, and ammonia production using direct oxy-combustion sCO2 power cycle with automatic CO2 capture, water electrolyzer, and Haber-Bosch process

Renewable energy-based multigeneration systems for power, hydrogen, and ammonia production suffer from intermittency issues and high production costs. On the other hand, conventional fossil-fuel-based systems yield high levels of CO2 emissions. Thus, to eliminate the intermittency issue with low production costs and near zero CO2 emissions, a novel integrated, efficient, compact, and interactive system for power, hydrogen (H2), and ammonia (NH3) production is developed and investigated in this study. A direct oxy-combustion supercritical carbon dioxide (DOC-sCO2) power plant is integrated with a water electrolyzer (WE) and Haber-Bosch process (HBP) system for the cogeneration of power, H2, and NH3, respectively. The power consumption of the air separation unit (ASU) of the DOC-sCO2 cycle is significantly reduced by the utilization of the oxygen produced from the WE system. Moreover, the cost of ammonia production is minimized by the internal utilization of the nitrogen gas produced by the ASU. Furthermore, the feedwater of the WE system is supplied internally from the DOC-sCO2 power block. In addition, the CO2 emissions of the system are captured to realize near-zero emissions to the ambiance. Based on these features, thorough energy, exergy, economic, and environmental (4E) analyses were performed to evaluate the performance of the proposed system. The obtained results showed an impressive levelized cost of electricity of 3.72¢/kWh, levelized cost of hydrogen of 1.162$/kgH2, and ammonia of 0.197$/kgNH3 at an overall energy and exergy efficiencies of 44.09 %, and 63.6 %, respectively. The system has no emissions of nitrogen oxides (NOx) and reduces the CO2 emissions of the H2 production by 49.6 % and of the NH3 production by 48.8 % compared to the conventional gasification, SMR, and HBP systems, respectively. This research work also provides insights into wet versus dry cooling, part load operation, and the advantages over renewable-based systems in terms of stability, reliability, and economic feasibility.

Deciphering the roles of nitrogen source in sharping synchronous metabolic pathways of linear alkylbenzene sulfonate and nitrogen in a membrane biofilm for treating greywater

Nitrogen (N) source is an important factor affecting biological wastewater treatment. Although the oxygen-based membrane biofilm showed excellent greywater treatment performance, how N source impacts the synchronous removal of organics and N is still unclear. In this work, how N species (urea, nitrate and ammonia) affect synchronous metabolic pathways of organics and N were evaluated during greywater treatment in the membrane biofilm. Urea and ammonia achieved efficient chemical oxygen demand (>97.5%) and linear alkylbenzene sulfonate (LAS, >98.5%) removal, but nitrate enabled the maximum total N removal (80.8 ± 2.6%). The nitrate-added system had poor LAS removal ratio and high residual LAS, promoting the accumulation of effluent protein-like organics and fulvic acid matter. N source significantly induced bacterial community succession, and the increasing of corresponded functional flora can promote the transformation and utilization of microbial-mediated N. The nitrate system was more conducive to the accumulation of denitrification related microorganisms and enzymes, enabling the efficient N removal. Combining with high amount of ammonia monooxygenase that contributing to LAS and N co-metabolism, LAS mineralization related microbes and functional enzymes were generously accumulated in the urea and ammonia systems, which achieved the high efficiency of organics and LAS removal.

Role of Crystal Seed in Aluminum Hydroxide Crystallization from Ammonia System with Added NH4Al(SO4)2·12H2O

Role of Crystal Seed in Aluminum Hydroxide Crystallization from Ammonia System with Added NH4Al(SO4)2·12H2O

Growth process of boehmite with large particles in ammonia system

The development of a novel technology for extracting aluminum resources from coal fly ash through direct leaching with an ammonium hydrogen sulfate solution represents a significant advancement. A pivotal stage within this process is the reaction crystallization between NH4Al(SO4)2·12H2O solid and NH3·H2O. Despite its many benefits, the fine particle size of the resultant product has impeded its widespread adoption. To tackle this challenge, this study concentrated on examining the growth mechanism of boehmite with larger particles in the presence of ammonia. Analysis revealed a distinct morphological evolution process for large-particle boehmite, progressing from a flaky morphology to a flower-like nanostructure with flaky features, and then further transitioning into particles displaying flower-like nanostructures and culminating in the formation of large particles with smooth surfaces. Initially, the early stages of crystallization were governed by kinetic factors, followed by a self-assembly phase, ultimately resulting in the final morphology of large particles, dictated by thermodynamic considerations. Density functional theory calculations underscored the significant role of H2O molecule adsorption in boehmite's growth trajectory, leading to the formation of pseudo-boehmite and inducing shifts in the X-ray diffraction peaks. The growth units remained integral throughout the entirety of the crystal growth process.

Optimal capacity and multi-stable flexible operation strategy of green ammonia systems: Adapting to fluctuations in renewable energy

The potential of power-to-ammonia is increasingly recognized as a large-scale renewable electrical energy storage technology in the energy-transition landscape. Unlike conventional, continuously operating Haber-Bosch production processes, power-to-ammonia processes face operational challenges stemming from fluctuations in renewable power supply. Systematic strategies that can adapt to these fluctuations are required to improve the operational flexibility and stability of power-to-ammonia processes for industrial applications. This study proposes a multi-stable flexible ammonia operation strategy, which is practical and feasible in engineering. To maximize net profit, a design scheduling coordination optimization model is established and solved using a two-stage algorithmic framework of particle swarm and mixed integer linear programming. Additionally, three flexible scenarios are designed for the simulation analysis of a grid-connected green ammonia system. Compared with the traditional constant inflexible scenario, the multi-stable flexible scenario increases annual net profit by 5.05 M$ and reduces carbon emission intensity by 1.61 kg CO2/kgNH3. Furthermore, compared with the continuous flexible scenario, the volatility of the ammonia production load is reduced by 79.89 %. The multi-stable flexible operation strategy balances the green ammonia system’s economic, safety, and low-carbon attributes. Sensitivity analysis reveals that wind and photovoltaic complementary power generation reduces green ammonia costs and carbon emissions. When the selling price of ammonia exceeds 550 $/t, ammonia production and sales should be prioritized, but at lower ammonia prices, selling electricity to the grid to optimize economic efficiency is advised. This study provides novel insights into the flexible operation of the power-to-ammonia process and is expected to offer guidance for constructing and operating green ammonia systems.

Advanced design for CO2 compressors in industrial applications

Distribution centers, ware houses, food processing plants - CO2 applications in industrial scale are increasingly becoming the focus of operators, OEM’s and the refrigeration industry. Applications with 2 MW cooling capacity are no longer a rarity. Installations with the required capacity of up to 4 MW split between several systems with up to 65 compressors operate successfully. The convincing arguments in favour of the carbon dioxide installations are: lower safety requirements, less space for the machine room and good seasonal energy efficiency compared to installations with ammonia. Following the development of this trend BITZER designed compressors with eight cylinders for industrial applications. The main focus of the development was besides the usually high operational safety, efficiency, capacity regulation and a low oil carry over rate. This publication gives an overview of the system solutions applied in industrial scaled applications with carbon dioxide as refrigerant. Based on this, the paper describes the design of a new generation of compressors and its potential for industrial applications. It is not intended as a competitor to ammonia system solutions, but rather as an additional solution that is sustainable and based on a natural refrigerant.

Environmental Effects of Using Ammonium Sulfate from Animal Manure Scrubbing Technology as Fertilizer

Processed manure products have the potential to substitute chemical fertilizers and the use of these products may increase resource efficiency in the food system and decrease emissions of ammonia (NH3) and greenhouse gasses (GHG). The yields of maize and grass, as well as emissions, have been determined from a processed manure product: liquid ammonium sulfate from nitrogen stripping animal manure (AS), in comparison to a regular mineral fertilizer, calcium ammonium nitrate (CAN), in a greenhouse experiment and a field demonstration using a sandy and a clay soil. NH3 emissions were determined by comparing AS with a dairy manure as a reference. The yield of both crops, their nitrogen nutrient use efficiency (NUE), and nitrous oxide (N2O) emissions were not significantly different, while NH3 emission was lower from AS compared to the dairy manure. As a side-effect, the sulfur (S) contents of the grass in the fields fertilized with AS were much higher than in the non-fertilized control. We conclude that AS, produced here with a pH &lt; 5.5, can be used as an alternative for CAN in Dutch dairy systems, or similar other system, if S leaching losses do not pose a problem for the environment. Meanwhile, care should be taken not to exceed S in feed above toxic levels for ruminants.

Simulating X-ray Absorption Spectroscopy in Challenging Environments: Methodological Insights from Water-Solvated Ammonia and Ammonium Systems.

Core-electron excitations in solvated systems, influenced by solvent geometry and hydrogen bonding, make X-ray absorption spectroscopy (XAS) a valuable tool for assessing solvent-solute interactions. However, calculating XAS spectra with electronic-structure methods has proven challenging due to a delicate interplay between correlation and solvation effects. This study provides a computational procedure for XAS modeling in solvated systems, with water-solvated ammonia and ammonium systems serving as probes. Exploring methodological challenges, we investigate explicit embedding models, specifically the polarizable embedding family, including polarizable density embedding and extended polarizable density embedding. Our linear-response time-dependent density functional theory (LR-TDDFT) XAS calculations reveal the efficiency of this approach, with extended polarizable density embedding emerging as a robust improvement over polarizable density embedding. Contrary to some recent literature, our study challenges the belief that LR-TDDFT cannot accurately describe XAS spectra of ammonia and ammonium solvated in water.

Neural network potential-based molecular investigation of pollutant formation of ammonia and ammonia-hydrogen combustion

This study developed neural network potentials (NNPs) specifically designed for ammonia and ammonia-hydrogen combustion systems for the first time. The NNPs were employed to perform reactive molecular dynamics (RMD) simulations, combining the precision of density functional theory (DFT) calculations with the efficiency of empirical force fields. NNP-based RMD simulations provide a more detailed and comprehensive understanding of chemical reaction mechanisms. The impacts of different equivalence ratios and hydrogen addition on ammonia combustion as well as NOX and N2O formation were analysed. The results indicate that both the addition of hydrogen and the reduction of equivalence ratios contribute to enhancing ammonia combustion. The primary reason is the enhancement of the oxidative environment within the system, leading to a significant increase in the frequency of reactions associated with oxidising radicals such as OH, O, and HO2. This is also the cause for the increased production of NO and NO2, because the formation of NO depends on the oxidation of NH and NH2, while NO2 is formed through the oxidation of NO. An interesting finding is that the addition of hydrogen decelerates the generation of N2O, while reducing the equivalence ratio promotes N2O production. This phenomenon is attributed to the additional H radicals generated during hydrogen decomposition, which hinders the binding between NH and NO, resulting in a reduction in the formation of the precursor HN2O required for N2O formation.

Acidic adjustment treatment of diatomite and its application in a novel powder-water mist synergistic decontamination system for ammonia

NH3·H2O can result in severe accidents when leaking in a confined space. In this work, a novel powder-water mist synergistic strategy for decontaminating NH3·H2O in a confined space is proposed. Initially, FeCl3/AlCl3 was employed to modify diatomite, decorating its pore structure and augmenting the number of acidic adsorption sites. The modified diatomite achieves a notable efficiency of 74.6%, surpassing that of the raw diatomite (43.8%). Subsequently, surfactants were introduced to increase the contact area between the water mist and NH3, while a thickening agent was employed to suppress the fluidity of NH3·H2O. Ultimately, the powder-water mist synergistic decontamination system was constructed by integrating the diatomite with a thickening agent and water mist containing surfactants. The synergistic system exhibits a superior decontamination efficiency of approximately 80%. This work generates fresh insight into decontaminating NH3·H2O in a confined space and offers a crucial avenue for future advancements in decontamination technology.

Comparing methanol and glycerol as carbon sources for mainstream partial denitrification/anammox in an IFAS process.

This study explored the implementation of mainstream partial denitrification with anammox (PdNA) in the second anoxic zone of a wastewater treatment process in an integrated fixed film activated sludge (IFAS) configuration. A pilot study was conducted to compare the use of methanol and glycerol as external carbon sources for an IFAS PdNA startup, with a goal to optimize nitrogen removal while minimizing carbon usage. The study also investigated the establishment of anammox bacteria on virgin carriers in IFAS reactors without the use of seeding, and it is the first IFAS PdNA startup to use methanol as an external carbon source. The establishment of anammox bacteria was confirmed in both reactors 102 days after startup. Although the glycerol-fed reactor achieved a higher steady-state maximum ammonia removal rate because of anammox bacteria (1.6 ±0.3g/m2/day) in comparison with the methanol-fed reactor (1.2±0.2g/m2/day), both the glycerol- and methanol-fed reactors achieved similar average in situ ammonia removal rates of 0.39 ±0.2g/m2/day and 0.40 ±0.2g/m2/day, respectively. Additionally, when the upstream ammonia versus NOx (AvN) control system maintained an ideal ratio of 0.40-0.50 g/g, the methanol-fed reactor attained a lower average effluent TIN concentration (3.50 ±1.2mg/L) than the glycerol-fed reactor (4.43 ±1.6mg/L), which was prone to elevated nitrite concentrations in the effluent. Overall, this research highlights the potential for PdNA in IFAS configurations as an efficient and cost-saving method for wastewater treatment, with methanol as a viable carbon source for the establishment of anammox bacteria. PRACTITIONER POINTS: Methanol is an effective external carbon source for an anammox startup that avoids the need for costly alternative carbon sources. The methanol-fed reactor demonstrated higher TIN removal compared with the glycerol-fed reactor because of less overproduction of nitrite. Anammox bacteria was established in an IFAS reactor without seeding and used internally stored carbon to reduce external carbon addition. Controlling the influent ammonia versus NOx (AvN) ratio between 0.40 and 0.50 g/g allowed for low and stable TIN effluent conditions.

Optimal Sizing and Pricing of Grid-Connected Renewable Power to Ammonia Systems Considering the Limited Flexibility of Ammonia Synthesis

Optimal Sizing and Pricing of Grid-Connected Renewable Power to Ammonia Systems Considering the Limited Flexibility of Ammonia Synthesis

Investigation of the use of foams for silver leaching using the thiosulfate‑copper(II)-ammonia system in the context of e-waste recycling

Due to its physical properties, metallic silver is present in numerous electronic wastes. Its recycling requires selective extraction, which involves leaching of silver as the first step. This work focusses on leaching silver with Cu(II)/NH3/S2O32− which has been widely used for gold leaching. As recently shown for the leaching of copper, using foams whose aqueous phase consists of leaching chemicals is a promising way to reduce the environmental footprint, by improving the metal oxidation caused by the fast transfer of O2 from bubble to bubble. In this work, metallic silver samples are dissolved by foams made of Cu(II)/NH3/S2O32− solution with bubbles composed of O2-N2 mixtures. The main problem of the thiosulfate route is its degradation during metal oxidation hence it requires using large quantities of this reactant. The results obtained for our leaching foams show that the quantity of silver leached per quantity of thiosulfate used is about three times greater in comparison with a solution, which would bring a new approach to this problem. Moreover, we investigate the role of the bubble size and the gas composition (dioxygen partial pressure). Besides we find that the dissolved silver is inhomogeneously distributed between the foam column and the bottom solution, with an accumulation of 90 % of silver inside the foam, hence opening an interesting perspective for an easy separation of silver upon leaching. Comparing several surfactants, we show that only non-ionic surfactant polyoxyethylene oleyl ether, Brij O10, shows satisfying results, while dodecyl trimethyl ammonium chloride most likely binds with silver complexes and triggers a quick collapse of the foams.

Near-Infrared Off-Axis integrated cavity output spectroscopic sensor system for ammonia leakage measurement in cold store using embedded Multi-Core processor

A near-infrared off-axis integrated cavity output spectroscopic (OA-ICOS) sensor system for ammonia (NH3) leakage detection was developed. A distributed feedback (DFB) laser was used to target the absorption line of NH3 at 6612.167 cm−1. Experiments were conducted to evaluate the performance of the sensor system. When the averaging time is 0.8 s, the detection limit (1σ) of NH3 is ∼ 1.21 parts-per-million by volume (ppmv) using wavelength modulation spectroscopy (WMS). The 10–90 % response time of the NH3 sensor system is ∼ 7.2 s. Based on the developed local monitoring and control platform (LMCP), cloud server, remote monitoring and control end (RMCE), the unattended NH3 leakage detection experiments were carried out in a cold store located in Jilin City. The experimental results confirmed the rapid detection capability of the reported sensor system for NH3 leakage as well as the capability of remote monitoring and control.