Hydroxylammonium Nitrate Research Articles

Evaluation of hydroxylammonium nitrate (HAN) decomposition using bifunctional catalyst for thruster application

Monopropellant thruster technology is at the cusp of revival with new age ionic liquids which are safe, less toxic and high performing emerging as substitutes for traditionally used hydrazine. One such promising candidate is Hydroxylammonium nitrate (HAN). Current study explores an iridium metal impregnated bifunctional variant of an earlier developed doped cerium oxide catalyst for HAN decomposition. The performance of bifunctional catalyst was compared against unsupported cerium oxide catalyst and conventional iridium over gamma alumina catalyst. Thermal analysis was the primary test used for performance evaluation and was subsequently followed up in a batch reactor to evaluate the durability of the catalyst to extreme high temperature exposure. Characterization of catalyst before and after decomposition reaction was comprehensively conducted using surface area analysis, SEM/EDS, XRD and XPS. Results did suggest promotional effect of iridium over doped ceria support as demonstrated through increased pressure build-up and rate of pressure-rise.

Pulse radiolysis study on the reactivity of NO3˙ radical toward uranous(iv), hydrazinium nitrate and hydroxyl ammonium nitrate at room temperature and at 45 °C.

Concentrated nitric acid solutions subjected to radiation produce radicals of extreme importance in the reprocessing of spent nuclear fuel. Knowledge of the different rate constants of the reactions involved in this chemistry is needed to improve the efficiency of the process and to define safe operating practices. Pulse radiolysis measurements are performed to find the rate constant of the reaction between NO3˙ radicals and U(iv) in highly concentrated nitrate solution. The optimal stabilization conditions toward thermal oxidation are defined for the considered solutions at room temperature and at 45 °C by adding anti-nitrous agents such as hydrazinium nitrate (HN) and hydroxyl ammonium nitrate (HAN). The decay of the NO3˙ radical is monitored and its reaction rates with HN, HAN and U(iv) are found to be 1.3 × 105, 1.5 × 107 and 1.6 × 106 M-1 s-1 at room temperature. The latter value is more than 10 times lower than the one currently used in numerical codes for simulation of the long-term radiolytic degradation associated with the reprocessing and storage of spent nuclear waste. At 45 °C, conditions similar to the reprocessing of spent fuel, the values of the rate constants of NO3˙ radical toward HN, HAN and U(iv) increase and are found to be 2.6 × 105, 2.9 × 107 and 9.3 × 106 M-1 s-1.

Wet Synthesis of Hydroxylammonium Nitrate (HAN) and Solid Phase Extraction Using Dual Organic Solvents

Wet Synthesis of Hydroxylammonium Nitrate (HAN) and Solid Phase Extraction Using Dual Organic Solvents

Experimental and analytical study on electrolytic decomposition of HAN-water solution using graphite electrodes

This paper describes the investigation of electrolytic decomposition of hydroxylammonium nitrate (HAN)-water solution using graphite electrodes. The decomposition reaction consists of two stages. Electrical energy was consumed for 5 s before the stage 1 reaction ceased. An interesting phenomenon was observed in the stage 2 reaction where the decomposition of HAN resumed after the power supply was switched off. A series of spectroscopy and microscopy analyses confirmed that the production of nitric oxide (NO) in the stage 1 reaction causes the formation of nitrous acid (HNO2), which leads to a further autocatalytic reaction. The reaction mechanisms were proposed and compared with the case of using copper electrodes. Graphite electrodes were demonstrated as more energy efficient in initiating the electrolytic decomposition of HAN-water solution as lower energy consumption (342 J) was achieved in comparison to copper electrodes (1926 J).

Thermal decomposition and kinetics of electrically controlled solid propellant through thermogravimetric analysis

The thermal decomposition behavior of electrically controlled solid propellant (ECSP) with hydroxyl ammonium nitrate as oxidizer and polyvinyl alcohol as binder was investigated through thermogravimetric analysis and differential scanning calorimetry coupling technology at the heating rates of 15, 20, 25, 30, and 35 K min−1 in nitrogen. Results indicated that the Tinitial and Tmax values of the thermal decomposition of ECSP increase with heating rates. The activation energy Eα from the results of TG data at various heating rates was calculated by model-free isoconversional Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods. The activation energies obtained through the FWO method were close to those obtained through the KAS method, and the values for activation energy were located between 42.82 and 48.49 kJ mol−1. An appropriate reaction mechanism conversion model for ECSP was determined by Malek and Coats–Redfern methods. Thermal decomposition kinetics of the ECSP obeyed the random nucleation and subsequent growth model, called Avrami–Erofeev function.

New Nanocarbon High-Energy Materials

The differential thermal analysis is applied to study the influence of activated carbon with multilayer graphenes (three and more sheets) on the thermal decomposition of a substance based on hydroxylammonium nitrate and carboxyl methyl cellulose. It is demonstrated that addition of activated carbon with multilayer graphenes lead to an increase in the burning rate of hydroxylammonium nitrate up to four times. Addition of activated carbon at the stage of thermal decomposition leads to a decrease in temperature and time of the chemical reaction until complete decomposition of ammonium nitrate.

Hydroxylammonium Nitrate Species in a Monopropellant Electrospray Plume

A mixture of 1-ethyl-3-methylimidazolium ethyl sulfate () and hydroxylammonium nitrate (HAN) is an energetic monopropellant potentially suitable in a multimode chemical-electric microtube-electrospray micropropulsion system. In this work, electrospray plume mass spectra are compared between the monopropellant mixture and neat . This comparison clearly indicates new and additional species present in the plume due to the addition of HAN. Mass spectra from 20 to were obtained over a variety of angles and flow rates from to in both cation and anion extraction modes. Mass spectra dependence on flow rate and angular orientation agree qualitatively well with literature. Results indicate the presence of HAN-based species in anion mode, but no HAN-based species in cation mode. Three of the four monomer species from the monopropellant are apparent in the plume; , , and are observed, whereas is noticeably absent. Results also show emission of both proton-transferred covalent forms of HAN: [HA-H] and . Swapping of anion and cation species between the constituents of the monopropellant mixture is also observed.

Calorimetric study on electrolytic decomposition of hydroxylammonium nitrate (HAN) ternary mixtures

Electrolytic decomposition of hydroxylammonium nitrate (HAN) is appealing for development of chemical micropropulsion system due to its effectiveness in thermal management. In this paper we present the decomposition characteristics and behaviour of various HAN ternary mixtures prepared according to 0 Oxygen Balance (0 OB). There are multiple stages of decomposition depending on the type of fuels added into the HAN solution. While concentrated HAN solution (73 wt%) has only single stage of decomposition, the saccharides-based HAN ternary mixtures has three stages reaction with increased energy release. The addition of nitrogen-rich compounds has sustained the electrolytic decomposition process into the second stage of reaction, which produced the highest decomposition temperature. The study also reveals a linear relationship between the electrical resistivity of HAN ternary mixture and reaction rate in the first stage of reaction, indicating the presence of Joule heating in the process. The influence of electrical resistivity of the ternary mixture became negligible in the second stage of reaction. This work concludes the importance of combined electrical and thermal energy in the first stage decomposition of HAN ternary mixtures.

Fabrication and preliminary testing of hydroxylammonium nitrate (HAN)-based ceramic microthruster for potential application of nanosatellites in constellation formation flying

Constellation formation flying of nanosatellites (< 10 kg) is becoming a trend for future space exploration missions. Liquid chemical micropropulsion that can provide high thrusting force for high ΔV orbital transfer is a crucial hardware component for successful constellation re-positioning. However, liquid chemical micropropulsion system dedicated for these nanosatellites still not currently available in the market. In this study, a microthruster was fabricated using alumina toughened zirconia (ATZ) as structural material and yttria-stabilised zirconia-graphene (YSZ-Gr) as electrode material. The device has a dimension of 1.7 cm (length) × 1.3 cm (width) × 0.5 cm (thickness) and weighing only 6.18 grams, comprising of five major components such as propellant reservoir, injector, electrodes, micronozzle and reaction chamber. Material characterization shows that both materials have negligible weight loss and small reduction in material hardness and fracture toughness after 20 thermal-vacuum cycles. Moreover, results from dynamic mechanical analysis (DMA) ascertain that addition of graphene significantly enhanced the damping behaviour of the zirconia composite. Electrolytic decomposition of hydroxylammonium nitrate (HAN) solution in the reaction chamber has been demonstrated with maximum thrust of 180.53 mN at a propellant flow rate of 60 µl/s. The preliminary results suggest that the HAN-based ceramic microthruster could potentially be used as primary propulsion for nanosatellites in constellation formation flying.

Advances in phase stabilization techniques of AN using KDN and other chemical compounds for preparing green oxidizers

Abstract Research and development of green oxidizers and green fuels as a possible replacement for ammonium perchlorate (NH4ClO4, AP) and hydrazine (N2H4) respectively has been increased considerably in the recent years. AP and hydrazine are the oxidizer and fuel entities, and used in solid and liquid rocket motors respectively. AP is highly toxic and led to adverse health effects, while hydrazine is carcinogenic in nature. AP is in use from the last several decades for rocket and space shuttle propulsion, while hydrazine is used in upper stage liquid propelled rocket motors. It's a tough task to replace AP with the currently available green oxidizers; since their ballistic properties are weaker when compared to AP and also they can't be successfully deployed in a solid rocket motor at present. Some important available solid green oxidizers are ammonium nitrate (AN), ammonium dinitramide (ADN), hydroxyl ammonium nitrate (HAN), and hydrazinium nitroformate (HNF). However, AN is one of the cheap and readily available oxidizer, and has great potential to use in solid/ liquid rocket motors. Tremendous progress has been envisaged till now, and more progress will be there in the coming future over the development of AN based green energetic materials (GEM's). A concise overview has been presented over the development of phase stabilized ammonium nitrate (PSAN) and AN/KDN based green oxidizers in the present review paper.

Catalytic Decomposition of an Energetic Ionic Liquid Solution over Hexaaluminate Catalysts

The objective of this study was to determine the effect of a synthesis procedure of Sr hexaaluminate on catalytic performance during the decomposition of ionic liquid monopropellants based on ammonium dinitramide (ADN) and hydroxyl ammonium nitrate (HAN). Sr hexaaluminates were prepared via both coprecipitation and a sol–gel process. The surface area of hexaaluminate synthesized via the coprecipitation method was higher than that of hexaaluminate synthesized by the sol–gel process, and calcined at the same temperature of 1200 °C or more. This is because of the sintering of α-Al2O3 on the hexaaluminate synthesized via the sol–gel process, which could not be observed on the catalysts synthesized via the coprecipitation method. The hexaaluminate synthesized via coprecipitation showed a lower decomposition onset temperature during the decomposition of ADN- and HAN-based liquid monopropellants in comparison with the catalysts synthesized via the sol–gel process, and calcined at the same temperature of 1200 °C or more. This is attributed to the differences in the Mn3+ concentration and the surface area between the two hexaaluminates. Consequently, the hexaaluminate synthesized via coprecipitation which calcined above 1200 °C showed high activity during the decomposition of energetic ionic liquid monopropellants compared with the hexaaluminate synthesized via the sol–gel process.

Propulsion systems and low-thrust rocket engines based on various physical principles for control systems of small and micro-spacecraft

The article presents an analysis of the possibility of using propulsion systems and rocket thrusters based on various physical principles and used as part of small and very small spacecraft. The parameters of efficient propulsion systems and low-thrust rocket engines are examined from the standpoint of being used as components of spacecraft fueled by various kinds of propellant: gaseous fuel, mono-fuel, including advanced compositions based on hydroxyl-ammonium nitrate, bipropellant fuel; xenon electric rocket systems, as well as special propulsion systems and low-thrust rocket engines operating on nitrous oxide, ammonia, gaseous hydrogen and oxygen; electric-powered systems based on pulsed plasma thrusters, ion and steady-state plasma engines. Taking into account the data analyzed, an attempt was made to categorize the propulsion systems and low-thrust rocket engines. Their use in small spacecraft, spacecraft of the Mini, Micro, Nano classes in various propulsion systems and low-thrust rocket engines was found to be preferable.

Thermal Decomposition Mechanism of Aqueous Hydroxylammonium Nitrate (HAN): Molecular Simulation and Kinetic Modeling.

A detailed mechanism has been developed for thermal decomposition of hydroxylammonium nitrate (HAN) solutions, based on quantum mechanical calculations using the SMD-ωB97X-D method. The mechanism describes multiple kinetic processes, including nitration and nitrosation of hydroxylamine, HNO dimerization, and HONO-regeneration pathways involving H-abstraction reactions. Rate constants of elementary reactions were estimated using transition state theory with consideration of species' diffusion effect. Kinetic modeling was performed to predict species' evolutions in 0.1 m HAN in the temperature range of 463-523 K, and results show reasonable agreement with the experimental data from flow reactor studies. For more concentrated solutions, strong autocatalytic behaviors were predicted with the late emergence of NO2 and HONO, whose regeneration was previously considered as the major autocatalytic pathway. Sensitivity analysis results suggest an acid-catalyzed nitration-nitrosation pathway, based on which the autocatalysis should be caused by the rise of solution acidity. A linear correlation can be observed in the previously reported apparent Arrhenius parameters, which may be reconciled via a kinetic compensation effect.

Recent developments in ceramic microthrusters and the potential applications with green propellants: a review

Conventional chemical propellants such as hydrazine and ammonium perchlorate have been used within the realm of contemporary space propulsion devices and are well established owing to their rich heritage. However, their limitations such as toxicity, difficulty in operational handling and environmental impacts have raised concerns. In view of these limitations, the significance of green propellants such as hydroxylammonium nitrate, hydrogen peroxide (H2O2) and ammonium dinitramide has become more pronounced. In this paper, recent developments in ceramic microthrusters and the associated ceramic microfabrication techniques are reviewed. The characteristics of green propellants are examined, followed by the evaluation of previous attempts to incorporate green propellants into ceramic microthrusters. This has further unveiled the possibilities of green and clean space missions in the future.

Influence of Activated Carbon on the Thermal Decomposition of Hydroxylammonium Nitrate

This paper presents experimental results for the thermal decomposition of hydroxylammonium nitrate (HAN) in the presence of activated carbon with a high specific surface (up to 3000 m2/g) obtained by activation of rice husk with potassium hydroxide at a temperature of 700°C in a rotating spherical furnace. The addition of activated carbon reduces the temperature of the onset of decomposition of HAN from 185 to 86 ± 0.5°C. The burning rate of HAN doped with activated carbon increases to 400 mm/s at an overpressure of 6 MPa. It has been shown that the addition of activated carbon reduces the amount of NO x gases produced by decomposition to 30%.

Thermoanalytical studies on the thermal and catalytic decomposition of aqueous hydroxylammonium nitrate solution

Green monopropellants based on hydroxylammonium nitrate (HAN) are a promising alternative to hydrazine in space propulsion systems. In the present paper, thermal and catalytic decomposition of aqueous HAN solution was studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mass spectrometry. The tests were conducted at heating rates of 1, 2.5, 5, and 10 K/min. The values of the apparent activation energy obtained for thermal decomposition using TGA and DSC are 62.2 ± 3.7 kJ/mol and 57.5 ± 3.5 kJ/mol, respectively, and they are in agreement with the literature data for solid HAN and solutions with high concentrations of HAN. The obtained values of the pre-exponential factor, 2.24 × 104 s−1 for TGA and 3.55 × 103 s−1 for DSC, are lower by six to seven orders of magnitude than those reported in the literature for aqueous HAN solutions, apparently because of full vaporization of water from the HAN solution at the beginning of the TGA and DSC tests. The use of an iridium/rhodium foam catalyst decreased the temperature of full decomposition by over 60 °C. The value of the apparent activation energy obtained for the catalytic decomposition using TGA is 63.9 ± 2.5 kJ/mol, while the obtained value of the pre-exponential factor is 3.31 × 105 s−1.

Decomposition of hydroxylammonium nitrate in a low pressure flowing thermal capillary system

Hydroxylammonium nitrate (HAN) is a potential monopropellant for plasma-based electric propulsion thrusters. However, little is known about the thermal decomposition of HAN at pressures typically encountered in aerospace applications. In this study, using residual gas analysis (RGA) we examine the production of nitrous oxide (N2O), nitrosamide (H2N2O), and nitroxyl (HNO) by thermally decomposing HAN exposed to pressures between 2 and 50 mTorr. Initial expectation was that NO and NO2 would be the primary species producing signal at 30 and 46 m/z respectively. Kinetic modeling studies of HAN solution, however, attributed these signals to HNO and H2N2O, respectively. Thermal decomposition was achieved by passively injecting an aqueous HAN solution into a flowing thermal capillary and detecting the gas products with mass spectrometry. N2O and H2N2O produced relatively small signal with a minor pressure dependence at low temperatures and no pressure dependence above ~460 K. HNO produced a much larger signal relative to N2O and H2N2O and exhibited a high level of pressure dependence as temperature increased above the onset of thermal decomposition, ~393 K. These results indicate that the formation of N2O, H2N2O, and HNO is occurring not only in the bulk solution but possibly on the surface of the aqueous HAN solution and in the vapor phase immediately above the solution surface. The kinetics and mechanism of possible decomposition pathways to form these species are discussed.

Cerium oxide based active catalyst for hydroxylammonium nitrate (HAN) fueled monopropellant thrusters.

Hydroxylammonium nitrate (HAN) is an energetic ionic liquid which is fast emerging as a promising environmentally friendly, high performing monopropellant for space propulsion application. The high performance due to the higher adiabatic temperature for HAN based compositions also poses challenges as high temperature tolerant catalysts have to be developed for its decomposition. A novel cobalt doped cerium oxide based catalyst has been prepared by the co-precipitation route and characterized by SEM/EDS, XRD, and XPS. The effectiveness of the catalyst in decomposing HAN has been tested using thermo-analytical techniques. An evolved gas analysis (EGA) to examine decomposition products and the possible reaction mechanism was also performed using the hyphenated DTA-TG-FTIR technique. Formation of an in situ Ce3+/Ce4+ ion couple in ceria during co-precipitation was found to be critical in deciding the reactivity of HAN decomposition over the catalyst. The activity of the catalyst was also examined in a batch reactor for its longevity. The prepared catalyst was found to be more versatile and durable than a hitherto reported alumina supported iridium catalyst in the present studies.

Influence of Activated Coal on the Thermal Decomposition of Hydroxylammonium Nitrate

Influence of Activated Coal on the Thermal Decomposition of Hydroxylammonium Nitrate

Combustion Characteristics of HAN-based Green Propellant Assisted with Nanoporous Active Carbons

Combustion of hydroxylammonium nitrate (95 wt.% HAN) ‒ water solution in presence of high specific surface area activated carbons is investigated in a constant-pressure bomb within the pressure range of 1‒6 MPa. The linear burning rate increased for the system of HAN admixed with activated carbons compared to those of the HAN alone. Moreover, the thermal decomposition of HAN (95 wt.%) ‒ water solution spiked with activated carbons was assessed by DTA – TG method. In the presence of activated carbons, the ability to trigger the decomposition at a lower temperature (86 °C vs 185 °C) was observed. The volatile products formed in the course of thermal decomposition of HAN, spiked with activated carbons were characterized by electron ionization mass spectrometry analysis. Primary products of HAN decomposition: m/z = 33 (NH2OH) and m/z = 63 (HNO3), which are further responsible for the formation of secondary products such as N2O, NO, HNO2, NO2, O2 etc. Significant reduction of NOx emissions during thermal decomposition of HAN (95 wt.%) ‒ water solution was observed (ca. 30%) in presence of activated carbons.