Ammonia Utilization Research Articles

A high-performance and durable direct NH3 tubular protonic ceramic fuel cell integrated with an internal catalyst layer

Nickel-based cermet anode-supported protonic ceramic fuel cells (PCFCs) show great potential for direct utilization of ammonia. However, the insufficient activity of anode and the deterioration of anode activity/durability caused by the undesired interaction between nickel and ammonia greatly limit the application. Here, we report tubular PCFCs embedded with a catalytic iron layer. Such cells show peak power densities of 1.507 W cm-2 and 1.078 W cm-2 at 700 °C when using H2 and NH3 as fuel, respectively, which are the highest tubular PCFC performance so far ever reported. In addition, the stability of cells with the catalyst layer has been dramatically enhanced when compared with that of cells without the catalyst layer. The enhancement of activity and durability is attributed to the catalytic activity of iron for ammonia decomposition, through which the direct contact between nickel and ammonia has been minimized and the anode structure has therefore been protected.

Ammonia/oxygen-enriched air continuous rotating detonation in the hollow chamber

As a carbon-free and renewable energy source, ammonia can help to mitigate global warming. However, the utilization of ammonia is currently limited by its low chemical reactivity and flame consumption velocity. In contrast to deflagration, detonation has the inherent advantage of a faster heat release rate, which makes it a promising approach for ammonia utilization. In this study, the ammonia/oxygen-enriched air continuous rotating detonation (CRD) was first realized in a hollow chamber. The ammonia CRD wave propagated in single-wave mode with a velocity of 1753 m/s, which accounts for 77.16% of the theoretical Chapman–Jouguet (C-J) velocity. An analysis of the integral of chemiluminescence (ICI) was conducted based on images obtained using high-speed photography to reconfirm the stable propagation of the CRD wave. In the experiment, the ammonia CRD could be realized when the oxygen mass fraction (OMF) was at least 43%. The operating range clearly decreased as the OMF decreased from 83% to 43%. The axial ICI peak gradually moved downstream with reductions in OMF and equivalence ratio, indicating afterburning of the ammonia CRD. The enhanced combustion downstream led to a circumferential excess of the CRD wave structure downstream, which was verified through CRD flow-field reconstruction.

Whole set of constitutive promoters for RpoN sigma factor and the regulatory role of its enhancer protein NtrC in Escherichia coli K-12.

The promoter selectivity of Escherichia coli RNA polymerase (RNAP) is determined by its promoter-recognition sigma subunit. The model prokaryote E. coli K-12 contains seven species of the sigma subunit, each recognizing a specific set of promoters. Using genomic SELEX (gSELEX) screening in vitro, we identified the whole set of ‘constitutive’ promoters recognized by the reconstituted RNAP holoenzyme alone, containing RpoD (σ70), RpoS (σ38), RpoH (σ32), RpoF (σ28) or RpoE (σ24), in the absence of other supporting regulatory factors. In contrast, RpoN sigma (σ54), involved in expression of nitrogen-related genes and also other cellular functions, requires an enhancer (or activator) protein, such as NtrC, for transcription initiation. In this study, a series of gSELEX screenings were performed to search for promoters recognized by the RpoN RNAP holoenzyme in the presence and absence of the major nitrogen response enhancer NtrC, the best-characterized enhancer. Based on the RpoN holoenzyme-binding sites, a total of 44 to 61 putative promoters were identified, which were recognized by the RpoN holoenzyme alone. In the presence of the enhancer NtrC, the recognition target increased to 61–81 promoters. Consensus sequences of promoters recognized by RpoN holoenzyme in the absence and presence of NtrC were determined. The promoter activity of a set of NtrC-dependent and -independent RpoN promoters was verified in vivo under nitrogen starvation, in the presence and absence of RpoN and/or NtrC. The promoter activity of some RpoN-recognized promoters increased in the absence of RpoN or NtrC, supporting the concept that the promoter-bound NtrC-enhanced RpoN holoenzyme functions as a repressor against RpoD holoenzyme. Based on our findings, we propose a model in which the RpoN holoenzyme fulfils the dual role of repressor and transcriptase for the same set of genes. We also propose that the promoter recognized by RpoN holoenzyme in the absence of enhancers is the ‘repressive’ promoter. The presence of high-level RpoN sigma in growing E. coli K-12 in rich medium may be related to the repression role of a set of genes needed for the utilization of ammonia as a nitrogen source in poor media. The list of newly identified regulatory targets of RpoN provides insight into E. coli survival under nitrogen-depleted conditions in nature.

Development of an ammonia production method for carbon-free energy generation

Ammonia has great prospects in the context of the transition to carbon-free energy. It can be used as fuel in gas turbines, fuel cells, internal combustion engines, and burned together with coal. However, industrial production of ammonia is based on the Haber-Bosh process, which involves the use of natural gas and coal, which, in this case, does not make it really carbon-free. This study proposes a method to produce ammonia, which is environmentally friendly and does not require the use of fossil fuels. It is based on the approach to adjusting the concentration of ammonium nitrogen in a biogas reactor and implies the sorption of ammonia from the gas phase with a solution of monoammonium phosphate, obtaining diammonium phosphate, and subsequently heating it with the release of ammonia. The factors influencing the extraction of ammonia from waste have been considered, as well as the influence of temperature on the release of ammonia from the solution of diammonium phosphate; the energy efficiency of the method has been assessed. With increasing temperature, the degree of ammonia and the degree of sorbent regeneration increased. Under laboratory conditions, 111 J/g of ammonia energy was spent. The higher the concentration of (NH4)2HPO4 in the solution, the less energy is required to obtain a unit of ammonia mass. The total amount of ammonia released varies depending on the temperature. Sorbent regeneration can be carried out using thermal energy obtained at a cogeneration plant. The possibility of using this method to produce ammonia at an industrial scale has been estimated by analyzing the ways of ammonia utilization as a fuel. The potential for ammonia production in the main livestock industries in Europe and the United States is up to 11,482,651.15 and 11,582,169.5 tons per year, respectively. Applying this solution also makes it possible to improve the efficiency of biogas production from waste with high nitrogen content. The proposed method of ammonia production could potentially contribute to the development of carbon-free energy

Applying heat flux method to laminar burning velocity measurements of NH3/CH4/air at elevated pressures and kinetic modeling study

Combustion of ammonia (NH3) blended fuels under elevated pressure conditions is critical for adopting this non-carbon fuel in the energy system for decarbonization. In the present work, laminar burning velocities of ammonia/methane(CH4)/air mixtures were measured using the heat-flux method at the pressure from 1 to 5 atm with the mixture equivalence ratios ranging from 0.6 to 1.6 and the mole fraction of NH3 ranging from 0 to 1.0. The relatively completed results obtained at elevated pressures were then used for validating and modifying the kinetic mechanisms (CEU-NH3-Mech 1.0) leading to a new version (CEU-NH3-Mech-1.1). Experimental results of NH3/H2/air in the present work, NH3/H2/CO/air mixtures measured on the same setup and reported in our previous works were also considered in the development of the kinetic mechanism. It was found that the CEU-NH3−Mech-1.1 can predict well the laminar flame speed, ignition delay time and species concentration in the ammonia oxidation at high temperatures for both NH3/CH4/air and NH3/H2/CO/air mixtures in a wide range of equivalence ratios and elevated pressures, including oxygen-enriched combustion conditions. The present experimental results also show that the value of pressure exponent (β) varies with the mole fraction of ammonia and behaves differently for the mixtures of ammonia blending into CH4 and H2. The kinetic and sensitivity analyses show that the sensitive reactions for β are weakly correlated to those for the laminar burning velocity, indicating that β can also work as a potential parameter for validating kinetic mechanisms. Ammonia content in the NH3/CH4/air mixtures determines the pressure exponent variation at over-rich equivalence ratios and reaction pathway variation in the post-flame zone. This work also clarifies the utilization of ammonia containing fuels in rich-lean combustion strategies.

AVL’s SOC Solutions Addressing Current Technology Trends and Drivers Towards Green Electricity Generation and Fuel Production

This work presents an overview of AVL’s most recent development activities in the field of SOC based power generation and fuel production. In particular, highlights from ongoing projects will be discussed. Detailed results will be presented in separate papers in the course of this conference to address the main technology and application trends which are currently driving the SOC industry. The main highlights will be the development of a 1 MW Power-to-Liquid plant, a reversible SOC system based on hydrogen operation as well as an ammonia fueled SOFC system.A thermodynamic analysis as well as the basic plant concept of a fully integrated SOEC-Fischer-Tropsch Power-to-Liquid plant for a highly efficient production of diesel was carried out. The project provides the unique possibility to design the plant by optimizing and integrating both processes, SOEC and Fischer-Tropsch, in the most efficient manner. Compared to existing concepts based on the connection of existing SOEC and FT systems, this approach will enable a significant efficiency boost of the overall plant. Especially, the coupling of the heat integration of both processes will be the key for overall efficiencies of 50-55 %. Eventually, estimates of diesel prices in the range of 1-3 EUR/L are discussed as an alternative to fossil based diesel.Local hydrogen production and re-electrification via a reversible operated SOC system are investigated in order to capture excess electricity from renewable power generation. The development addresses a 15 kW rSOC system which will be operated in combination with PV under real conditions. Innovative system architectures towards highest total efficiencies (electricity and hydrogen production) are the core of the first phase of the project. Application specific boundary conditions are discussed with respect to its impact on system design.One of the most heavily discussed trends is the direct utilization of ammonia for power generation in an SOFC system. Green ammonia production is seen as a very promising alternative to conventional fuels to address CO2 reduction while keeping the energy density at a relatively high level as it is needed for example in maritime applications. AVL will present the results of its ammonia based SOFC system development and discuss it in the context of power propulsion and auxiliary power for different ship applications. Furthermore, the efficiency chain as well as a comparison with other technologies such as ICE and PEM will complete the detailed investigation.

Effects of O2 enrichment on NH3/air flame propagation and emissions

The potential utilization of ammonia as a carbon-free fuel under oxygen (O2)-enriched condition is demonstrated, suggesting its practically appropriate burning conditions by measuring and predicting the combustion characteristics of outwardly-propagating spherical O2-enriched NH3/air premixed flames at normal temperature and pressure. Measured and computed laminar burning velocities and predicted flame structure exhibit that the O2-enriched ammonia/air flames become thinner and propagate faster with O2 enrichment. Observed flame morphologies and measured and computed Markstein numbers reveal that all the present O2-enriched flames are stable in terms of the flamefront cellular instability due to preferential diffusion and the effects of O2 enrichment on the instability are negligible. Volume-based 35–40% O2 in the nonfuel mixtures demonstrates the proper burning intensity for practical applications, comparable to the typical hydrocarbon/air flames. In the present flame configuration, however, local nitrogen oxides emissions are found to be high, which should be substantially reduced in the practical systems.

Emerging Materials and Methods toward Ammonia-Based Energy Storage and Conversion.

Efficient storage and conversion of renewable energies is of critical importance to the sustainable growth of human society. With its distinguishing features of high hydrogen content, high energy density, facile storage/transportation, and zero-carbon emission, ammonia has been recently considered as a promising energy carrier for long-term and large-scale energy storage. Under this scenario, the synthesis, storage, and utilization of ammonia are key components for the implementation of ammonia-mediated energy system. Being different from fossil fuels, renewable energies normally have intermittent and variable nature, and thus pose demands on the improvement of existing technologies and simultaneously the development of alternative methods and materials for ammonia synthesis and storage. The energy release from ammonia in an efficient manner, on the other hand, is vital to achieve a sustainable energy supply and complete the nitrogen circle. Herein, recent advances in the thermal-, electro-, plasma-, and photocatalytic ammonia synthesis, ammonia storage or separation, ammonia thermal/electrochemical decomposition and conversion are summarized with the emphasis on the latest developments of new methods and materials (catalysts, electrodes, and sorbents) for these processes. The challenges and potential solutions are discussed.

Dehydrogenation of ammonia for electricity production: Effect of recirculation fraction

Hydrogen (H2) has been widely studied as a promising energy carrier. However, H2 has a challenging technology in the storage and transportation. Since, it is a critical technology for H2 energy system implementation, the H2 storage and transportation is remain to be solved. This work proposes an integrated system of energy utilization of ammonia (NH3), which has been known as one of the promising methods of H2 storage. The system includes the decomposition of ammonia (NH3) through thermo-catalytic process and also power generation process using H2 as fuel. The heat generated from oxy-fuel combustion of H2 is utilized to supply the thermal energy required for the endothermic process of NH3 decomposition, and the remaining heat is converted to electricity by a combined cycle. A portion of exhaust gas is recirculated to the combustion chamber, and the heat circulation of the system is designed and optimized based on enhanced process integration (EPI), resulting in a highly efficient system. The result shows an optimum configuration of the integrated system with a recirculation fraction of 0.5-0.55, which is resulting in high system efficiency of 51.4%. The proposed work demonstrated an integrated system of H2-based energy utilization of NH3 with CO2-free while maintaining a highly efficient system.

Оценка эффективности сжигания аммиаксодержащего газа в реакционных печах установки Клауса с использованием методов вычислительной гидродинамики

Based on the computational fluid dynamics method using ANSYS Fluent software, we carried out a simulation of acid gases combustion process in the Claus furnaces with further combustion of ammonia containing gas originated from sour water stripper. The sulphur recovery unit of the heavy residue conversion complex owned by TAIF-NK was considered as a research subject. As per the results of CFD-simulation, the optional scenarios were defined for utilization of ammonia containing acid gases in the sulphur recovery unit by adjustment of gas composition, thermodynamic conditions, as well as by controlling the flow pattern in the Furnace. The data obtained agree quite well with the actual performance parameters of the existing unit and the findings in the public domain.

Metabolic markers for diagnosis and risk-prediction of multiple myeloma

AimsTo discriminate metabolic biomarkers for diagnosis and risk prediction of multiple myeloma (MM) on a basis of metabolic characteristics in systemic circulation and local pathogenic niche. Main methodsA gas chromatography mass spectrometry-based untargeted metabolomics analysis was performed within the bone marrow (BM) supernatants and peripheral plasma from healthy donors and patients with MM. Key findingsDistinct metabolic features between MM patients and healthy volunteers were profiled in both BM and plasma. Metabolic profiles of subgroups in which MM patients undergo high/medium/low risk displayed risk-dependent metabolic shift especially in BM. In MM patients, up-regulated glutamate level and down-regulated glutamine level in BM indicated enhanced glutamate metabolism which provided NH4+ for ammonia utilization. This resulted in increased level of urea and creatinine produced from urea cycle, arginine and proline metabolism in both BM and plasma collected from MM patients. The disorders of tricarboxylic acid cycle and carnitine synthesis were unique in BM of MM patients. Receiver operating characteristic curve analysis indicated that aspartate was a candidate plasma biomarker for diagnosis with the highest sensitivity and specificity in both BM and plasma. Threonine was identified as a preferential plasma biomarker for risk prediction due to significant relation with various risk indexes of MM in both BM and plasma. SignificanceThe perturbed glutamate metabolism and carnitine synthesis in BM of MM patients provided a new sight on pathogenesis of MM. The plasma level of aspartate and threonine may become a preferential metabolic marker for diagnosis and risk prediction of MM, respectively.

Cultivation of anaerobic ammonium oxidizing bacteria (AnAOB) using different sewage sludge inoculums: process performance and microbial community analysis

AbstractBACKGROUNDThis study explores the feasibility of three different inoculum sources (anaerobic, aerobic, and anoxic sludge from conventional sewage treatment plants) together with the potential of biomass carrier for Anaerobic ammonium oxidation bacteria (anammox) cultivation. Fed‐batch reactors were operated with synthetic medium at different temperatures.RESULTSThe reactor inoculated with anaerobic sludge and biomass carrier showed close to stoichiometric nitrite to ammonia utilization (1.2:1) and the highest ammonia removal (12.2 mg NH4+·g VS−1·day−1), followed by the reactor inoculated with activated sludge without carrier (4.3 mg NH4+·g VS−1·day−1), which also showed close to stoichiometric nitrite to ammonia utilization. Anammox development was recorded by higher nitrogen removal, gradually increasing gas production rate, and the presence of Brocadiaceae anammox family bacteria. All batch reactors revealed significant phosphorus removal (>80%), which was attributed to the co‐existence of anammox bacteria (Brocadiaceae) with denitrifying polyphosphate accumulating organisms (flavobacterium sp.).CONCLUSIONThe results of this study revealed that anaerobic sludge and activated sludge from sewage treatment plants with biomass carriers for microbial immobilization were suitable for anammox bacteria enrichment. The co‐existence of anammox bacteria with denitrifying polyphosphate accumulating microorganisms reveals new possibilities for simultaneous nitrogen and phosphate removal. © 2020 Society of Chemical Industry (SCI)

Greening the production and utilization of ammonia

Abstract

Specialized adaptations allow vent-endemic crabs (Xenograpsus testudinatus) to thrive under extreme environmental hypercapnia

Shallow hydrothermal vent environments are typically very warm and acidic due to the mixing of ambient seawater with volcanic gasses (> 92% CO2) released through the seafloor making them potential ‘natural laboratories’ to study long-term adaptations to extreme hypercapnic conditions. Xenograpsus testudinatus, the shallow hydrothermal vent crab, is the sole metazoan inhabitant endemic to vents surrounding Kueishantao Island, Taiwan, where it inhabits waters that are generally pH 6.50 with maximum acidities reported as pH 5.50. This study assessed the acid–base regulatory capacity and the compensatory response of X. testudinatus to investigate its remarkable physiological adaptations. Hemolymph parameters (pH, [HCO3−], {text{P}}_{{{text{CO}}_{2} }}, [NH4+], and major ion compositions) and the whole animal’s rates of oxygen consumption and ammonia excretion were measured throughout a 14-day acclimation to pH 6.5 and 5.5. Data revealed that vent crabs are exceptionally strong acid–base regulators capable of maintaining homeostatic pH against extreme hypercapnia (pH 5.50, 24.6 kPa {text{P}}_{{{text{CO}}_{2} }}) via HCO3−/Cl− exchange, retention and utilization of extracellular ammonia. Intact crabs as well as their isolated perfused gills maintained {text{P}}_{{{text{CO}}_{2} }}tensions below environmental levels suggesting the gills can excrete CO2 against a hemolymph-directed {text{P}}_{{{text{CO}}_{2} }} gradient. These specialized physiological mechanisms may be amongst the adaptations required by vent-endemic animals surviving in extreme conditions.

Ammonia as Effective Hydrogen Storage: A Review on Production, Storage and Utilization

Ammonia is considered to be a potential medium for hydrogen storage, facilitating CO2-free energy systems in the future. Its high volumetric hydrogen density, low storage pressure and stability for long-term storage are among the beneficial characteristics of ammonia for hydrogen storage. Furthermore, ammonia is also considered safe due to its high auto ignition temperature, low condensation pressure and lower gas density than air. Ammonia can be produced from many different types of primary energy sources, including renewables, fossil fuels and surplus energy (especially surplus electricity from the grid). In the utilization site, the energy from ammonia can be harvested directly as fuel or initially decomposed to hydrogen for many options of hydrogen utilization. This review describes several potential technologies, in current conditions and in the future, for ammonia production, storage and utilization. Ammonia production includes the currently adopted Haber–Bosch, electrochemical and thermochemical cycle processes. Furthermore, in this study, the utilization of ammonia is focused mainly on the possible direct utilization of ammonia due to its higher total energy efficiency, covering the internal combustion engine, combustion for gas turbines and the direct ammonia fuel cell. Ammonia decomposition is also described, in order to give a glance at its progress and problems. Finally, challenges and recommendations are also given toward the further development of the utilization of ammonia for hydrogen storage.

In Situ Synthesis of MoS2 on C3N4 To Form MoS2/C3N4 with Interfacial Mo–N Coordination for Electrocatalytic Reduction of N2 to NH3

Electrocatalytic nitrogen reduction reaction (NRR), as an alternative to synthetic ammonia under mild condition, provides a promising method for storage and sustainable utilization of ammonia. Howe...

Peptization of alumina by ammonia to adjust catalytic properties of NiMo/B-Al2O3 hydrotreating catalysts

NiMo/B-Al2O3 catalysts for VGO hydrotreating differed in peptizing agent for supports preparation (nitric acid or ammonium solution) have been studied. The molar ratio of HNO3/Al2O3 = 0.03 and NH3aqua/Al2O3 = 0.09 and 0.15 were used. Supports and catalysts were studied by the nitrogen and mercury adsorption, IR-spectroscopy of adsorbed CO, XRD, 11B and 27Al NMR, UV–vis DRS, HRTEM, XPS. NiMo/B-Al2O3 catalyst peptized by ammonia at molar ratio of NH3/Al2O3 = 0.09 contains higher amount of NiMoS phase than catalysts peptized by nitric acid. Boron catalyst based support peptized by nitric acid is characterized by active component particles with lower slab length. Simultaneous presence of ammonia and boron results in increase of the slab length of active component, while stacking number decreases. According to the results of catalytic testing in HDS of DBT, boron-containing catalysts are more active. However, NiMo/B-Al2O3 catalyst obtained using ammonia with molar ratio of NH3/Al2O3 = 0.09 has higher activity in HDS of DBT in comparison with NiMo/B-Al2O3 catalyst obtained using nitric acid. Testing in VGO hydrotreating confirmed that utilization of ammonia as a peptizing agent for support preparation significantly improves the activity of boron catalyst in HDS and HDN reactions.

Composition and functional profiling of the microbiota in the casts of Eisenia fetida during vermicomposting of brewers’ spent grains

Vermicomposting is a cost-effective biotechnology for the management of organic wastes that relies on the activity of earthworms and their associated microbiota. Here, the microbiotas of the earthworm Eisenia fetida fed with brewers’ spent grains (FBSG), cow manure (FCM) and a mix of brewers’ spent grains/cow manure (FMIX), were identified by high-throughput DNA sequencing (16S rRNA). Bacterial community variance was correlated with the pH and the organic carbon content of the rearing substrates. FBSG microbiota was enriched in Paenibacillaceae, Enterobacteriaceae, Chitinophagaceae and Comamonadaceae. In addition, FBSG microbiota had a predicted higher abundance of genes involved in cellulose degradation as well as in the nitrogen cycle and showed higher utilization of ammonia and nitrate. Results obtained will allow to optimize the vermicomposting of brewers’ spent grains and to evaluate the effect of vermicompost addition on nutrient dynamics in soil.

Hyperammonemia in clinical practice: analysis of own clinical observations

The article presents scientific data on the role of ammonia in the human body, examines in detail the mechanism of formation and utilization of ammonia in the body. The questions of etiology and separate forms of pathogenesis of hyperammonemia, and its influence on the processes of fibrosis in the liver and the role of stellate liver cells in it are highlighted separately. The data on the influence of hyperammonemia on cognitive functions of the brain with the development of encephalopathy are presented, which is of great importance in clinical practice, during medical examination. The data of own observations are given, the questions of drug therapy are highlighted.

The differential proliferation of AOB and NOB during natural nitrifier cultivation and acclimation with raw sewage as seed sludge.

Nitrifier immigration from sewers to wastewater treatment systems is attracting increasing attention for understanding nitrifier community assembly mechanisms, and improving process modeling and operation. In this study, nitrifiers in raw sewage were cultivated and acclimated in a sequencing batch reactor (SBR) for 90 days to investigate the characteristics of the influent nitrifiers after immigration. During the experiment, specific nitrite utilization rate (SNUR) exceeded specific ammonia utilization rate (SAUR) when floc size reached 224 ± 46 μm, and nitrogen loss occurred at the same time. The ratio of nitrite oxidizing bacteria (NOB) to ammonia oxidizing bacteria (AOB) increased from 0.84 to 2.14 after cultivation. The Illumina MiSeq sequencing showed that the dominant AOB was Nitrosomonas sp. Nm84 and unidentified species, and the three most abundant Nitrospira were Nitrospira defluvii, Nitrospira calida, and unidentified Nitrospira spp. in both raw sewage and cultivated activated sludge. The shared reads of raw sewage and activated sludge were 48.76% for AOB and 89.35% for Nitrospira. These indicated that nitrifiers, especially NOB, immigrated from influent can survive and propagate in wastewater systems, which may be a significant hinder to suppress NOB in the application of advanced nitrogen remove process based on partial nitrification in the mainstream.