Characterisation and thrust measurements from electrolytic decomposition of Ammonium Dinitramide (ADN) based liquid monopropellant FLP-103 in MEMS thrusters

Although Ammonium Dinitramide (ADN) has been targeted as a potential green monopropellant in future space vehicles, its application potential in Micro-electrical-Mechanical System (MEMS) thrusters or microthrusters have seldom reported in open literature. In this paper, electrolytic decomposition of Ammonium dinitramide (ADN)-based liquid monopropellant FLP-103 were carried out in open chamber and MEMS thrusters fabricated from Poly-Dimethylsiloxane (PDMS) to characterize the power consumption. Two thrust measurement methods were employed to investigate the electrolytic decomposition of FLP-103 in MEMS microthrusters. The results show that the monopropellant can be successfully ignited at room temperature through 80V,0.1A (8W) using copper wire as electrodes. In the current thruster design, low thrust was obtained at FLP-103 flowrate of 40µl/min but it generated the highest specific impulse, Isp, among all the flowrates tested. The experiments successfully demonstrated the potential application of electrolytic decomposition of FLP-103 in MEMS thrusters

Novel input-output prediction approach for biomass pyrolysis

Biomass pyrolysis to bio-oil is one of the promising sustainable fuels. In this work, relation between biomass feedstock element characteristic and pyrolysis process outputs was explored. The element characteristics considered in this study include moisture, ash, fix carbon, volatile matter, carbon, hydrogen, nitrogen, oxygen, and sulphur. A semi-batch fixed bed reactor was used for biomass pyrolysis with heating rate of 30 °C/min from room temperature to 600 °C and the reactor was held at 600 °C for 1 h before cooling down. Constant nitrogen flow rate of 5 L/min was provided for anaerobic condition. Rice husk, Sago biomass and Napier grass were used in the study to form different element characteristic of feedstock by altering mixing ratio. Comparison between each element characteristic to total produced bio-oil yield, aqueous phase bio-oil yield, organic phase bio-oil yield, higher heating value of organic phase bio-oil, and organic bio-oil compounds was conducted. The results demonstrate that process performance is associated with feedstock properties, which can be used as a platform to access the process feedstock element acceptance range to estimate the process outputs. Ultimately, this work evaluated the element acceptance range for proposed biomass pyrolysis technology to integrate alternative biomass species feedstock based on element characteristic to enhance the flexibility of feedstock selection

Element characteristic tolerance for semi-batch fixed bed biomass pyrolysis

Biomass pyrolysis to bio-oil is one of the promising sustainable fuels. In this work, relation between biomass feedstock element characteristic and crude bio-oil production yield and lower heating value was explored. The element characteristics considered in this study include moisture, ash, fix carbon, volatile matter, C, H, N, O, S, cellulose, hemicellulose, and lignin content. A semi-batch fixed bed reactor was used for biomass pyrolysis with heating rate of 30 °C/min from room temperature to 600 °C and the reactor was held at 600 °C for 1 h before cooling down. Constant nitrogen flow (1bar) was provided for anaerobic condition. Sago and Napier glass were used in the study to create different element characteristic of feedstock by altering mixing ratio. Comparison between each element characteristic to crude bio-oil yield and low heating value was conducted. The result suggested potential key element characteristic for pyrolysis and provide a platform to access the feedstock element acceptance range

Alternative raw material research for decarbonization of UK glass manufacture

Based on the current UK decarbonization policy, a general outlook on potential routes for the glass industry to achieve net‐zero is discussed and the differentiation during decarbonization is specified. Biomass ash is considered a potential alternative raw material for low‐carbon glass manufacture as it is rich in certain advantageous components, chiefly network modifiers. Simple sieving processes were shown to effectively separate impurities such as S, Cl, and C from some biomass ashes according to particle size distribution. The concentration of undesirable impurities decreased with increasing particle size. Morphologies and X‐ray diffraction patterns of larger washed biomass ash particles indicated liquid/amorphous phase formation during biomass combustion. The washing of ashes was also shown to be a potential route to purification. A washed bracken ash relevant to both modern and ancient glass production was characterized for comparison. Ultraviolet‐visible near‐infrared (UV‐Vis‐near IR) absorption spectra of representative green container glasses produced using biomass ash confirmed that ∼5 wt.% ash in representative glass batches has little impact on the color and redox state of glasses; the redox status of glass produced using >2 mm biomass ash after washing was less reduced than that of glass produced using high levels (>∼9 wt.%) of >2 mm biomass ash after sieving alone, observed via the redox couple Cr3+/Cr6+ by UV‐Vis‐near IR absorption spectroscopy

Valorization of Napier grass via intermediate pyrolysis: Optimization using response surface methodology and pyrolysis products characterization

This study presents first optimization report on pyrolysis oil derived from Napier grass. Effects of temperature, heating rate and nitrogen flow rate on the intermediate pyrolysis of Napier grass biomass in a vertical fixed-bed tubular reactor were investigated collectively. Response surface methodology with central composite design was used for modelling the process and optimization of the process variables. Individual second order polynomial model was found to be adequate in predicting bio-oil, bio-char and non-condensable gas yield. The optimum bio-oil yield of 50.57 wt% was recorded at 600 �C, 50 �C/min and 5 L/min nitrogen flow. The bio-oil obtained throughout this study was two-phase liquid, organic and aqueous phase. The bio-oil, bio-char and non-condensable gas were characterized using standard analytical techniques. The results revealed that the organic phase consists of hydrocarbons and various benzene derivatives, which can be further processed into fuels and valuable chemicals. The aqueous phase was predominantly water, acids, ketones, aldehydes and some phenolics and other water-soluble organics. The non-condensable gas was made up high hydrogen/carbon monoxide ratio suitable for liquid fuel synthesis via Fischer-Tropsch Synthesis. The bio-char was a porous carbonaceous material with high energy content, which can be applied as a solid fuel, adsorbent or source of biofertilizer. This study demonstrated that Napier grass biomass is a viable feedstock for production of high-value bioenergy precursors

Bioenergy potential of millet chaff via thermogravimetric analysis and combustion process simulation using Aspen Plus.

Millet chaff constitutes one of the most abundant agro-residues in the sub-Saharan Africa and its utilisation as a feedstock in developing sustainable bioenergy solutions is very sketchy. This study presents the first comprehensive physicochemical and combustion characteristics of millet chaff via thermogravimetric analysis and process simulation using Aspen Plus. The millet chaff sample was collected and assessed as received for proximate and ultimate analyses. The results showed the biomass has 71.25 wt%, 15.35 wt%, 13.40 wt% and 13.15 MJ/kg for volatile matter, fixed-carbon, ash content and higher heating value respectively. The material consists of low nitrogen and sulphur content with potassium, aluminium, magnesium, calcium, iron and sodium as the inorganic components. Kinetic study using distributed activation energy model (DAEM) revealed an average frequency factor and activation energy of 1.41 × 1018(s−1) and 149.39 kJ/mol. Ignition and burnout temperature in the range of 232-244°C and 430-489°C were recorded. The average combustion thermodynamic parameters; ΔH, ΔG and ΔS were found to be 144.75 kJ/mol, 167.12 kJ/mol and -40.08 J/mol. The combustion process analysis coupled with steam turbine cycle via process simulation revealed an excellent combustion efficiency at air-fuel ratio of 5.14. (stoichiometric air). The power generation and electric efficiency of 0.7kWh/kg and 21.07% respectively were recorded at 24% excess air with minimal environmental impacts. This suggests that millet chaff is a good biomass feedstock suitable for clean bioenergy production

Novel method for the determination of water content and higher heating value of pyrolysis oil

This research provides a novel approach for the determination of water content and higher heating value of pyrolysis oil. Pyrolysis oil from Napier grass was used in this study. Water content was determined with pH adjustment using a Karl Fischer titration unit. An equation for actual water in the oil was developed and used, and the results were compared with the traditional Karl Fischer method. The oil was found to have between 42 and 64% moisture under the same pyrolysis condition depending on the properties of the Napier grass prior to the pyrolysis. The higher heating value of the pyrolysis oil was determined using an oil-diesel mixture, and 20 to 25 wt% of the oil in the mixture gave optimum and stable results. A new model was developed for evaluation of higher heating value of dry pyrolysis oil. The dry oil has higher heating values in the range between 19 and 26 MJ/kg. The developed protocols and equations may serve as a reliable alternative means for establishing the actual water content and the higher heating value of pyrolysis oil

Pyrolysis of Napier grass in a fixed bed reactor:effect of operating conditions on product yields and characteristic

This study presents a report on pyrolysis of Napier grass stem in a fixed bed reactor. The effects of nitrogen flow (20 to 60 mL/min), and reaction temperature (450 to 650 degrees C) were investigated. Increasing the nitrogen flow from 20 to 30 mL/min increased the bio-oil yield and decreased both bio-char and non-condensable gas. 30 mL/min nitrogen flow resulted in optimum bio-oil yield and was used in the subsequent experiments. Reaction temperatures between 450 and 600 degrees C increased the bio-oil yield, with maximum yield of 32.26 wt% at 600 degrees C and a decrease in the corresponding bio-char and non-condensable gas. At 650 degrees C, reductions in the bio-oil and bio-char yields were recorded while the non-condensable gas increased. Water content of the bio-oil decreased with increasing reaction temperature, while density and viscosity increased. The observed pH and higher heating values were between 2.43 to 2.97, and 25.25 to 28.88 MJ/kg, respectively. GC-MS analysis revealed that the oil was made up of highly oxygenated compounds and requires upgrading. The bio-char and non-condensable gas were characterized, and the effect of reaction temperature on the properties was evaluated. Napier grass represents a good source of renewable energy when all pyrolysis products are efficiently utilized