Gas Temperature Research Articles

Optimization of exhaust ejector with lobed nozzle for marine gas turbine

To attain high-performance ejector configurations, an ejection characteristic testing system was established initially to validate the reliability of the Realizable k-ε turbulent model. Subsequently, optimization investigations were conducted on lobed nozzle ejectors with various structural parameters. The effects of four key structural parameters, including lobed nozzle expansion angle α, lobed nozzle width d, number of lobes in the nozzle n, and height of the square-to-circle section h, were systematically studied. Furthermore, the CRITIC method was employed for multi-objective evaluation to identify the optimal design configuration for the casing ejector. The research findings revealed that among the structural parameters, the lobed nozzle expansion angle α exerted the greatest influence on the ejection coefficient and pressure loss coefficient. The weights of the evaluation criteria were determined by the CRITIC method as follows: ejection coefficient (49.38%) < pressure loss coefficient (50.62%). The optimal design configuration determined by the CRITIC method included α = 45°, d = 150 mm, n = 14, and h = 600 mm. The resulting enclosure design ensures smooth airflow within the system, preventing the backflow of high-temperature mainstream fluid and heating the enclosure. It also maintains a temperature distribution in the typical cross-section that meets specified requirements. Additionally, it facilitates improved mixing of mainstream and secondary fluid and reduces exhaust gas temperature.

Research on IoT Based Industrial Monitoring and Protection System

Abstract: ESP32 microcontroller integration is used in an Internet of Things system created for industrial monitoring and security.The device has multiple sensors built in system to collect critical environmental and operating data, such as voltage, current, fire, MQ2 gas, and DHT11 temperature and humidity sensors. For remote monitoring and analysis, an IoT platform hosted in the cloudcan process and transmit data more easily thanks to the ESP32 microcontroller. Industrial parameters can be managed and visualizedin real time using the Blynk application as an interface. A DC fan, pump motor, buzzer, LCD display, and AC device control are examples of output actuators included in the system. Through using these actuators, industrial environments can be made safer and more efficiently run by enabling automated responses to recognized anomalies or predefined thresholds

Cosmology with galaxy cluster properties using machine learning

Context. Galaxy clusters are the largest gravitating structures in the universe, and their mass assembly is sensitive to the underlying cosmology. Their mass function, baryon fraction, and mass distribution have been used to infer cosmological parameters despite the presence of systematics. However, the complexity of the scaling relations among galaxy cluster properties has never been fully exploited, limiting their potential as a cosmological probe. Aims. We propose the first machine learning (ML) method using galaxy cluster properties from hydrodynamical simulations in different cosmologies to predict cosmological parameters combining a series of canonical cluster observables, such as gas mass, gas bolometric luminosity, gas temperature, stellar mass, cluster radius, total mass, and velocity dispersion at different redshifts. Methods. The ML model was trained on mock “measurements” of these observable quantities from Magneticum multi-cosmology simulations to derive unbiased constraints on a set of cosmological parameters. These include the mass density parameter, Ωm, the power spectrum normalization, σ8, the baryonic density parameter, Ωb, and the reduced Hubble constant, h0. Results. We tested the ML model on catalogs of a few hundred clusters taken, in turn, from each simulation and found that the ML model can correctly predict the cosmology from where they have been picked. The cumulative accuracy depends on the cosmology, ranging from 21% to 75%. We demonstrate that this is sufficient to derive unbiased constraints on the main cosmological parameters with errors on the order of ~14% for Ωm, ~8% for σ8, ~6% for Ωb, and ~3% for h0. Conclusions. This proof-of-concept analysis, though based on a limited variety of multi-cosmology simulations, shows that ML can efficiently map the correlations in the multidimensional space of the observed quantities to the cosmological parameter space and narrow down the probability that a given sample belongs to a given cosmological parameter combination. More large-volume, mid-resolution, multi-cosmology hydro-simulations need to be produced to expand the applicability to a wider cosmological parameter range. However, this first test is exceptionally promising, as it shows that these ML tools can be applied to cluster samples from multiwavelength observations from surveys such as Rubin/LSST, CSST, Euclid, and Roman in optical and near-infrared bands, and eROSITA in X-rays, to the constrain cosmology and effect of baryonic feedback.

In-flight iron ore reduction and nanoparticle formation in an atmospheric pressure hydrogen microwave plasma

The in-flight reduction of iron ore particles using an atmospheric pressure hydrogen plasma is investigated. Iron ore particles with a size less than 75 µm are aerosolized and carried with an argon-hydrogen (90%–10%) gas mixture through an atmospheric pressure microwave plasma. After the treatment, the collected particles are observed to follow three distinct populations: (i) fully reduced nanoparticles, (ii) partially reduced spheres, larger than the feedstock, and (iii) partially melted, partly reduced agglomerates. A model is developed to explain the possible mechanism for the origin of the three populations. The nanoparticles (i) are found to be likely formed from the previously evaporated material whereas the particles (ii) and (iii) result from the partial/complete melting of the particles and agglomerates flowing through the reactor. The gas temperature is estimated to be more than 2000 K, which enables the rapid melting, evaporation, and reduction of these particles within residence times of only a few 10 ms.

Impact of Pressure and Temperature on Charge Accumulation Characteristics of Insulators in Direct-Current Gas-Insulated Switchgear

Direct-current gas-insulated switchgear (DC GIS) is an important device for promoting the lightweight and compact design of offshore wind power platforms. Gas pressure and temperature gradients are crucial factors that must be considered during the design process of the DC GIS. In this study, the multi-physics coupling model of basin insulators considering surface charge accumulation was established, and the corresponding real-sized insulator surface charge measurement platform was constructed. The effects of gas pressure and temperature gradient on the surface charge accumulation characteristics were investigated, respectively. The results show that the effect of gas pressure on the surface charge distribution characteristics depends on the dominant mode of surface charge. When volume conduction is dominant, the effect of gas pressure on the surface charge is negligible. However, when gas conduction is dominant, the accumulation of a uniform charge pattern on the insulator surface increases with the rise in gas pressure. Furthermore, due to gas convection, the temperature of the upper part of the DC GIS is significantly higher than that of the lower part, which leads to a temperature difference between the upper and lower surfaces of the insulator. The charge density on the insulator upper surface near the central conductor rises with the increase in load current.

Experimental study on the discharge characteristics of air rotating gliding arc

Abstract In this study, the discharge characteristics of air rotating gliding arc are investigated by the synchronous measurements of digital oscilloscope and high-speed camera, and emission spectrum. The discharge evolution in one complete motion cycle exhibits “breakdown-elongation-extinction” process accompanied by the jump of arc root and back-breakdown phenomenon. The discharge evolves from the unstable breakdown mode (U-B), to the transition mode and finally to the stable gliding mode (S-G) by increasing the input voltage or decreasing the tangential and axial gas flow rates. The U-B mode at the input voltage of 120 V is featured by the large reduced electric field and high electron temperature of 1.90 eV, but the arc length and existence time are very short. The S-G mode at the input voltage of 270 V has relatively low breakdown frequency of 0.33 kHz and average breakdown current of 1.31 A, implying that the arc steadily glides and rotates along the spiral electrode. The average electron temperature is 0.64 eV in S-G mode, while the arc length and existence time are longer. The rotational and vibrational temperatures of N2 state are respectively measured to 2200 K and 4400 K in U-B mode, and in S-G mode are 2600 K and 4820 K. From the evolution of emission intensities of measured excited species, it is found that the NOγ band emission intensity generally rises from U-B mode to S-G mode since the gas temperature and arc existence time rise, indicating that S-G mode may be beneficial for the vibrationally-promoted Zeldovich reactions. This study could deepen the understanding of arc characteristics in air rotating gliding arc for selecting a suitable mode to achieve better plasma performance in practical applications.

Examining functional group-dependent effects on the ionization of lignin monomers using supercritical fluid chromatography/electrospray ionization mass spectrometry.

The chemical and biological conversion of biomass-derived lignin is a promising pathway for producing valuable low molecular weight aromatic chemicals, such as vanillin or guaiacol, known as lignin monomers (LMs). Various methods employing chromatography and electrospray ionization-mass spectrometry (ESI-MS) have been developed for LM analysis, but the impact of LM chemical properties on analytical performance remains unclear. This study systematically optimized ESI efficiency for 24 selected LMs, categorized by functionality. Fractional factorial designs were employed for each LM to assess ESI parameter effects on ionization efficiency using ultra-high-performance supercritical fluid chromatography/ESI-MS (UHPSFC/ESI-MS). Molecular descriptors were also investigated to explain variations in ESI parameter responses and chromatographic retention among the LMs. Structural differences among LMs led to complex optimal ESI settings. Notably, LMs with two methoxy groups benefited from higher gas and sheath gas temperatures, likely due to their lower log P and higher desolvation energy requirements. Similarly, vinyl acids and ketones showed advantages at elevated gas temperatures. The retention in UHPSFC using a diol stationary phase was correlated with the number of hydrogen bond donors. In summary, this study elucidates structural features influencing chromatographic retention and ESI efficiency in LMs. The findings can aid in developing analytical methods for specific technical lignins. However, the absence of an adequate number of LM standards limits the prediction of LM structures solely based on ESI performance data.

Experimental study of the effect of the temperature of inert gases on the intensity of thermal decomposition of rubber

THE PURPOSE. An experimental method is used to evaluate the effect of the temperature of inert gases on the rate of thermal decomposition of waste rubber products (fragments of a car tire) upon their direct contact.METHODS. The research was carried out on a test firing stand at a stationary mode of gas movement in the temperature range from 300 °C to 500 °C. The initial weight of the rubber was 4 grams. The thermal decomposition of rubber was carried out due to the thermal energy of inert gas released during the combustion of a propanebutane mixture with air at α = 1.1...1.15. The consumption of fuel and oxidizer remained constant, the change in gas temperature was carried out by heat exchange of hot gases and water in the heat exchanger.RESULTS. Metodology of conducting experiments, the object of research under the study, results of the research and their analysis are described in the article. The main parameters were selected: the rate of decrease in rubber mass depending on the temperature of the gases, the limiting value of the gas temperature at which sulfur in solid form remains in the decomposed part of the rubber.CONCLUSION. It was found that with increasing temperature of the inert gas, the rate of thermal decomposition of rubber increases. When rubber is in a gaseous environment in the temperature range from 450 0C to 500 0C, the sulfur content in the solid residue remains practically unchanged. The average rate of pyrolysis was 0.02 kg/h, which is 6 times higher than the rate of pyrolysis in the retort (0.003 kg/h).

Experimental investigation on high-temperature co-gasification and melting behavior of petrochemical sludge and bituminous coal in CO2 atmosphere

High-temperature co-gasification of petrochemical sludge (PS) and bituminous coal (BC) can melt heavy metals and fly ash in hazardous waste, decompose dioxins, and generate syngas, which can achieve clean disposal and high value resource utilization of wastes. In this investigation, the high-temperature co-gasification and ash melting experiments of PS mixed with BC were carried out in a high-temperature tube furnace under CO2 atmosphere. The effects of gasification temperature and blending ratios (PS:BC) on co-gasification characteristics and ash melting behavior were investigated. The synergistic effect of co-gasification of PS-BC was examined. The results show that the yield of syngas (CO + H2) was proportional to the temperature and the proportion of BC. As the temperature increased from 1100 °C to 1400 °C, the yield of syngas increased from 1.42 m3/kg to 1.54 m3/kg. At 1300 °C, as the blending ratio of PS:BC shifted from 1:0 to 0:1, the yield of syngas increased significantly from 0.49 m3/kg to 1.88 m3/kg. The most significant synergistic effect of PS-BC co-gasification was the enhanced CO yield. At a blending ratio of 1:1, the synergistic coefficient of CO yield reached a maximum of 1.31. As for the residues, with the increase of temperature and the proportion of BC, the ash melting got promoted. The leaching toxicity of heavy metals in the residues can meet the release standard (GB5805.3–2007), being safe for disposal.

Characteristics of dielectric barrier discharge and ozone production in synthetic air

This work studies the characteristics of electrical discharge, optical emission spectroscopy and ozone production of an air-fed dielectric barrier discharge reactor. In particular, the reactor utilizes water as the high voltage electrode and the grounding electrode. Results show that when the applied peak-to-peak voltage is increased from 16.8 kV to 26.8 kV at 10 kHz, the specific input energy is increased from 19.0 J/L to 664.9 J/L. The maximum ozone generation efficiency reaches about 155 g/kWh with an ozone concentration of around 1549 ppm. The results also show that at a peak-to-peak voltage of 24.0 kV, the typical rotational temperature is 306 ± 5 K. In addition, during a 400 min stability test with ozone concentrations up to about 6000 ppm, the ozone generation efficiency is stabilized at around 106 g/kWh. The reactor can provide optimized control of the gas temperature and realizes energy-efficient ozone generation.

Smart System for Monitoring and Controlling Harmful Gases in Avian Farming using IOT

The poultry industry is vital for sustaining global food production, yet it faces challenges concerning environmental sustainability and animal welfare. Among these, management of ammonia (NH3) and carbon dioxide (CO2) gas emissions, temperature, humidity fluctuations, and dust control, are critical considerations. Current methodologies often lack real-time monitoring capabilities and effective mitigation efforts. To address these issues, this research proposes an IoT-based monitoring and control system tailored for poultry farms, focusing on managing and controlling gas emissions, temperature, humidity, dust, and light levels. Employing an ESP32 microcontroller and sensors such as MQ135 for NH3 and CO2 detection, DHT for temperature and humidity, and LDR for light intensity, the system ensures continuous monitoring and adjustment of environmental parameter. It monitors and controls the dust by managing the proper temperature and humidity to reduce the health issues in poultry and as well as regulates light by turning ON/OFF light during dark. The system activates ventilation when the gas exceeds its limit and sends alerts through GSM. By using Wi-Fi connectivity, remote monitoring through a Blynk app is facilitated, while data logging on Thing Speak enables comprehensive analysis. The system aims to control ventilation and prevent dust for better environmental conditions and poultry welfare.

Complex organic molecules uncover deeply embedded precursors of hot cores

Context. During the process of star formation, the dense gas undergoes significant chemical evolution leading to the emergence of a rich variety of molecules associated with hot cores and hot corinos. However, the physical conditions and the chemical processes involved in this evolution are poorly constrained. In particular, the early phases, corresponding to a stage prior to the emergence of any strong ionising emission from the protostar, are still poorly studied. Aims. In this work, we provide a full inventory of the emission from complex organic molecules (COMs) to investigate the physical structure and chemical composition of six high-mass protostellar envelopes. We aim to investigate the conditions for the emergence of COMs in hot cores. Methods. We performed an unbiased spectral survey towards six infrared-quiet massive clumps between 159 GHz and 374 GHz with the APEX 12 m telescope, covering the entire atmospheric windows at 2 mm, 1.2 mm, and 0.8 mm. To identify the spectral lines, we used rotational diagrams and radiative transfer modelling assuming local thermodynamic equilibrium. Results. We detect up to 11 COMs plus three isotopologues, of which at least five COMs (CH3OH, CH3CN, CH3OCHO, CH3OCH3, and CH3CHO) are detected towards all sources. Towards all the objects, most of the COM emission is found to be cold, with respect to the typical temperatures at which COMs are found, with a temperature of 30 K and extended with a size of ~0.3 pc. Although the bulk of the gas for our sample of young massive clumps has a cold temperature, we also detect emission from COMs originating from the immediate vicinity of the protostar. This warm component of the envelope is best traced by methanol and methyl cyanide, in particular methyl cyanide traces a compact (~1″) and the hottest (T ~200 K) component of the envelope. Only three out of the six sources exhibit a robustly detected hot gas component (T > 100 K) traced by several COMs. We find a gradual emergence of the warm component in terms of size and temperature, together with an increasing molecular complexity, allowing us to establish an evolutionary sequence for our sample based on COMs. While they can already be well characterised by an emerging molecular richness, gas temperatures of COMs in the hot gas and molecular abundances suggest that COMs may become abundant in the gas phase at temperatures below the thermal desorption temperature. Conclusions. Our findings confirm that the sources of our sample of infrared-quiet massive clumps are in an early evolutionary stage during which the bulk of the gas is cold. The presence of COMs is found to be characteristic of these early evolutionary stages accompanying high-mass star and cluster formation. While the extent of the compact heated regions resembles that of hot cores, the molecular abundances, except for complex cyanides, resemble those of hot corinos and are lower than the peak COM abundances of hot cores. We suggest that the emergence of hot cores is preceded by a phase in which mostly O-bearing COMs appear first with similar abundances to hot corinos albeit with larger source sizes.

Experimental investigation on the high-temperature corrosion of 12Cr1MoVG boiler steel in waste-to-energy plants: Effects of superheater operating temperature and moisture

Waste-to-energy (WTE) technology via municipal solid waste incineration (MSWI) have developed very rapidly with the advantages of achievement on waste disposal and energy conversion. This technology is developing towards higher capacity and efficiency. Therefore, the operation parameters of WTE boilers must be improved. However, higher steam parameters means higher surface temperature of exchange tube in superheaters and reheaters in WTE boilers, resulting higher risk of engineering failure due to high-temperature corrosion. Additionally, the incineration of MSW releases flue gas with a high content of corrosive species and water vapor, which can cause severe high-temperature corrosion. This experimental investigation details the effect of surface temperature and water vapor concentration on the high-temperature corrosion behavior of 12Cr1MoVG boiler steel under an atmosphere mimicking MSWI. The corrosion test environment consists of high temperature, ash deposit and simulated flue gas of waste incineration according to a real WTE boiler. The experiment was conducted using a two-zone bench-scale tube furnace with a gas temperature of 600℃ and the sample temperatures of 380℃, 430℃, and 480℃. For the investigation of water vapor concentration effect, 18 % vol and 23 % vol were set up in this study. After 240 hours of exposure, the corrosion weight curves illustrated that the corrosion kinetics was highly dependent on the surface temperature of corrosion samples. Furthermore, an increase in water vapor concentration exacerbated the high-temperature corrosion. XRD analysis identified the corrosion products as metal chlorides and metal oxides. Cross-sectional SEM images and EDS analysis revealed that an increase in water vapor accelerated the corrosion rate of the steel samples due to chromium dilution behavior.

The effects of inner electrode shape on the performance of dielectric barrier discharge reactor for oxidative removal of NO and SO2

Seagoing vessels are responsible for more than 90% of global freight traffic, but meanwhile, emission pollutants (NO x and SO x ) of seagoing vessels also cause serious air pollution. Nonthermal plasma (NTP) combined with wet scrubbing technology is considered to be a promising technology. In order to improve the oxidation efficiency and energy efficiency of the NTP reactor, the screw and rod inner electrodes of dielectric barrier discharge (DBD) reactor were investigated. To analyze the mechanism, the optical emission spectra (OES) of NTP were measured and numerical calculation was applied. The experiment results show that the NO oxidation removal efficiency of screw electrode is lower than that of rod electrode. However, the SO2 removal efficiency of screw electrode is higher. According to the OES experiment and numerical calculation, the electric field intensity of the screw electrode surface is much higher than that of the rod electrode surface, and it is easier to generate N radicals to form NO. For the same energy density condition, the OH radical generation efficiency of the screw electrode reactor is similar to that of the rod electrode, but the gas temperature in the discharge gap is higher. Therefore, the SO2 oxidation efficiency of the thread electrode is higher. This study provides guidance for the optimization of oxidation efficiency and energy consumption of DBD reactor.

The penetration depth of atomic radicals in tubes with catalytic surface properties

Catalysis of molecular radicals is often performed in interesting experimental configurations. One possible configuration is tubular geometry. The radicals are introduced into the tubes on one side, and stable molecules are exhausted on the other side. The penetration depth of radicals depends on numerous parameters, so it is not always feasible to calculate it. This article presents systematic measurements of the penetration depth of oxygen atoms along tubes made from nickel, cobalt, and copper. The source of O atoms was a surfatron-type microwave plasma. The initial density of O atoms depended on the gas flow and was 0.7×1021 m−3, 2.4×1021 m−3, and 4.2×1021 m−3 at the flow rates of 50, 300, and 600 sccm, and pressures of 10, 35, and 60 Pa, respectively. The gas temperature remained at room temperature throughout the experiments. The dissociation fraction decreased exponentially along the length of the tubes in all cases. The penetration depths for well-oxidized nickel were 1.2, 1.7, and 2.4 cm, respectively. For cobalt, they were slightly lower at 1.0, 1.3, and 1.6 cm, respectively, while for copper, they were 1.1, 1.3, and 1.7 cm, respectively. The results were explained by gas dynamics and heterogeneous surface association. These data are useful in any attempt to estimate the loss of molecular fragments along tubes, which serve as catalysts for the association of various radicals to stable molecules.

A novel dielectric barrier discharge ozone generator with excellent microdischarge temperature behavior

In this paper, the electrical characteristics and optical emission spectroscopy of a dielectric barrier discharge ozone generator with water as the grounding electrode are investigated. The gas temperature of the microdischarge channel and at the reactor outlet have also been studied. Results show that the working plasma has a very small effect on the increase in gas temperature at the reactor outlet. At applied power frequency of 5 kHz and applied peak voltage of 7 kV, the microdischarge temperature is obtained as 310 K from N2(C3Πu → B3Πg) spectra ranging from 370-381 nm. In addition, the plasma emission spectra of gas mixtures (95 % O2 + 5 % N2) are investigated and the microdischarge temperature is determined as 309 K with applied power frequency of 5 kHz and applied peak voltage of 8 kV. It is concluded that observed microdischarge temperatures reaches the lowest values reported for filamentary air discharges, capable of promoting ozone production.

Influence of blowing ratio on double-wall cooling characteristics under the condition of high-temperature flue gas

Double-wall cooling has been extensively investigated due to its exceptional cooling performance. However, most previous studies on the cooling characteristics of double-wall geometry have been conducted under non-reacting conditions, neglecting the influence of high-temperature flue gas radiation. In this paper, an experiment investigation was carried out to evaluate the impact of blowing ratio <italic>M</italic> and coolant-to-gas temperature ratio on the cooling characteristics of effusion/impingement cooling at reacting flow conditions. The experiments were performed at atmospheric pressure with flame temperatures of 1,800 and 1,900 K respectively. Flue gas temperature was measured by S-type thermocouples, while an infrared camera and N-type thermocouples were employed for the gas-side wall surface temperature distribution measurements. The results demonstrate that the laterally averaged cooling effectiveness of the effusion/impingement cooling system increases with the increase of <italic>M</italic>. However, beyond a blowing ratio of 5.1, further increments in <italic>M</italic> do not significantly affect the cooling effectiveness. Moreover, it is observed that the laterally averaged cooling effectiveness gradually improves along the flow direction but at a reduced rate. Additionally, no significant changes in cooling effectiveness are observed after <italic>X</italic>/<italic>D</italic> > 50. Furthermore, when considering a blowing ratio of 4, higher coolant temperatures result in higher cooling effectiveness compared to lower coolant temperatures.

Visualizing Dynamic Single Atom Catalysis.

Many industrial chemical processes, including for producing fuels, foods, pharmaceuticals, chemicals and environmental controls, employ heterogeneous solid state catalysts at elevated temperatures in gas or liquid environments. Dynamic reactions at the atomic level play a critical role in catalyst stability and functionality. In situ visualization and analysis of atomic-scale processes in real time under controlled reaction environments can provide important insights into practical frameworks to improve catalytic processes and materials. This review focuses on innovative real time in situ electron microscopy (EM)methods, including recent progress in analytical insitu environmental (scanning) transmission EM (E(STEM), incorporating environmental scanning TEM (ESTEM) and environmental transmission EM (ETEM), with single atom resolution for visualizing and analysing dynamic single atom catalysis under controlled flowing gas reaction environments. ESTEM studies of single atom dynamics of reactions, and of sintering deactivation, contribute to a better-informed understanding of the yield and stability of catalyst operations. Advances in in situ technologies, including gas and liquid sample holders, nanotomography, and higher voltages, as well as challenges and opportunities in tracking reacting atoms, are highlighted. The findings show that the understanding and application of fundamental processes in catalysis can be improved, with valuable economic, environmental, and societal benefits.

Process Integration of Hydrogen Production Using Steam Gasification and Water-Gas Shift Reactions: A Case of Response Surface Method and Machine Learning Techniques

An equilibrium-based steady-state simulator model that predicts and optimizes hydrogen production from steam gasification of biomass is developed using ASPEN Plus software and artificial intelligence techniques. Corn cob’s chemical composition was characterized to ensure the biomass used as a gasifier and with potential for production of hydrogen. Artificial intelligence is used to examine the effects of the significant input variables on response variables, such as hydrogen mole fraction and hydrogen energy content. Optimizing the steam-gasification process using response surface methodology (RSM) considering a variety of biomass-steam ratios was carried out to achieve the best results. Hydrogen yield and the impact of main operating parameters were considered. A maximum hydrogen concentration is found in the gasifier and water-gas shift (WGS) reactor at the highest steam-to-biomass (S/B) ratio and the lowest WGS reaction temperature, while the gasification temperature has an optimum value. ANFIS was used to predict hydrogen of mole fraction, 0.5045 with the input parameters of S/B ratio of 2.449 and reactor pressure and temperature of 1 bar and 848°C, respectively. With the steam-gasification model operating at temperature (850°C), pressure (1 bar), and S/B ratio of 2.0, an ASPEN simulator achieved a maximum of 0.5862 mole fraction of hydrogen, while RSM gave an increase of 19.0% optimum hydrogen produced over the ANFIS prediction with the input parameters of S/B ratio of 1.053 and reactor pressure and temperature of 1 bar and 850°C, respectively. Varying the gasifier temperature and S/B ratio have, on the other hand, a crucial effect on the gasification process with artificial intelligence as a unique tool for process evaluation, prediction, and optimization to increase a significant impact on the products especially hydrogen.

A comparative study on the spectral characteristics of nanosecond pulsed discharges in atmospheric He and a He+2.3%H2O mixture

Nanosecond pulsed discharges at atmospheric pressure in a pin-to-pin electrode configuration are well reproducible in time and space, which is beneficial to the fundamentals and applications of low-temperature plasmas. In this experiment, the discharges in helium (He) and He with 2.3% water vapor (H2O) are driven by a series of 10 ns overvoltage pulses (~13 kV). Special attention is paid to the spectral characteristics obtained in the center of discharges by time-resolved optical emission spectroscopy. It is found that in helium, the emission of atomic and molecular helium during the afterglow is more intense than that in the active discharge, while in the He+2.3%H2O mixture, helium emission is only observed during the discharge pulse and the molecular helium emission disappears. In addition, the emissions of OH(A-X) and Hα present similar behavior that increases sharply during the falling edge of the voltage pulse as the electrons cool down rapidly. The gas temperature is set to remain low at 540 K by fitting the OH(A-X) band. A comparative study on the emission of radiative species (He, He2, OH and H) is performed between these two discharge cases to derive their main production mechanisms. In both cases, the dominant primary ion is He+ at the onset of discharges, but their He+ charge transfer processes are quite different. Based on these experimental data and a qualitative discussion on the discharge kinetics, with regard to the present discharge conditions, it is shown that the electron-assisted three-body recombination processes appear to be the significant sources of radiative OH and H species in high-density plasmas.