Investigation on the effects of steam/CO2/N2 on the flame suppression and flame stability of the methane-oxygen mixtures at elevated thermodynamic conditions

The present research aims to analyse diffusion flame in a tube type burner with Liquefied petroleum gas (LPG) as a fuel. An experimental investigation is performed to study flame appearance, flame stability, Soot free length fraction (SFLF) and CO emission of LPG diffusion flame. Effects of varying air and fuel velocities are analysed to understand the physical process involved in combustion. SFLF is measured to estimate the reduction of soot. Stability limits of the diffusion flame are characterized by the blowoff velocity. Emission characteristic in terms of CO level is measured at different equivalence ratios. Experimental results show that the air and fuel velocity strongly influences the appearance of LPG diffusion flame. At a constant fuel velocity, blue zone increases and the luminous zone decreases with the increase in air velocity. It is observed that the SFLF increases with increasing air velocity at a constant fuel velocity. It is observed that the blowoff velocity of the diffusion flame increases as fuel velocity increases. Comparison of emission for flame with and without swirl indicates that swirl results in low emission of CO and higher flame stability. Swirler with 45° vanes achieved the lowest CO emission of 30 ppm at Φ = 1.3.

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ROCK OIL RESERVOIR STRUCTURE INFLUENCE ON THE FLAME STABILITY OF THE IN-SITU COMBUSTION RECOVERY METHOD

10.26678/abcm.cobem2019.cob2019-0063 ◽

2019 ◽

Author(s):

Lucas Henrique Pagoto Deoclecio ◽

Filipe Arthur Firmino Monhol ◽

Antônio Carlos Barbosa Zancanella

Keyword(s):

Flame Stability ◽

Oil Reservoir ◽

In Situ Combustion ◽

Recovery Method

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Voltage rise anemometry in turbulent flows applied to internal combustion engines

Experiments in Fluids ◽

10.1007/s00348-021-03226-3 ◽

2021 ◽

Vol 62 (6) ◽

Author(s):

Michael Wörner ◽

Gregor Rottenkolber

Keyword(s):

Turbulent Flows ◽

Internal Combustion Engines ◽

Clear Correlation ◽

Combustion Engines ◽

Mean Flow ◽

Voltage Rise ◽

Mathematical Correlation ◽

Thermodynamic Conditions ◽

Secondary Voltage ◽

Cylinder Flow

AbstractIn an experimental procedure, a voltage rise anemometry is developed as a measurement technique for turbulent flows. Initially, fundamental investigations on a specific wind tunnel were performed for basic understanding and calibration purpose. Thus, a mathematical correlation is derived for calculating flow from measured secondary voltage of an ignition system under different thermodynamic conditions. Subsequently, the derived method was applied on a spark-ignited engine to measure in-cylinder flow. Therefore, no changes on combustion chamber were necessary avoiding any interferences of the examined flow field. Comparing four different engine configurations, a study of mean flow and turbulence was performed. Moreover, the results show a clear correlation between measured turbulence and analysed combustion parameters. Graphic abstract

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Crystal growth of clathrate hydrate formed with H2 + CO2 mixed gas and tetrahydropyran

Scientific Reports ◽

10.1038/s41598-021-90802-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Meku Maruyama ◽

Riku Matsuura ◽

Ryo Ohmura

Keyword(s):

Crystal Growth ◽

Synthesis Gas ◽

Water System ◽

Hydrate Formation ◽

Growth Dynamics ◽

Operating Conditions ◽

Mixed Gas ◽

Thermodynamic Conditions ◽

The Individual ◽

And Storage

AbstractHydrate-based gas separation technology is applicable to the CO2 capture and storage from synthesis gas mixture generated through gasification of fuel sources including biomass. This paper reports visual observations of crystal growth dynamics and crystal morphology of hydrate formed in the H2 + CO2 + tetrahydropyran (THP) + water system with a target for developing the hydrate-based CO2 separation process design. Experiments were conducted at a temperature range of 279.5–284.9 K under the pressure of 4.9–5.3 MPa. To simulate the synthesis gas, gas composition in the gas phase was maintained around H2:CO2 = 0.6:0.4 in mole fraction. Hydrate crystals were formed and extended along the THP/water interface. After the complete coverage of the interface to shape a polycrystalline shell, hydrate crystals continued to grow further into the bulk of liquid water. The individual crystals were identified as hexagonal, tetragonal and other polygonal-shaped formations. The crystal growth rate and the crystal size varied depending on thermodynamic conditions. Implications from the obtained results for the arrangement of operating conditions at the hydrate formation-, transportation-, and dissociation processes are discussed.

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Phase Diagram of Binary Alloy Nanoparticles under High Pressure

Materials ◽

10.3390/ma14112929 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2929

Author(s):

Han Gyeol Kim ◽

Joonho Lee ◽

Guy Makov

Keyword(s):

Phase Diagram ◽

Phase Diagrams ◽

Interaction Parameter ◽

Excess Volume ◽

Eutectic Temperature ◽

Calphad Method ◽

Alloy Nanoparticles ◽

Thermodynamic Conditions ◽

Nanoparticle System ◽

Pressure Phase

CALPHAD (CALculation of PHAse Diagram) is a useful tool to construct phase diagrams of various materials under different thermodynamic conditions. Researchers have extended the use of the CALPHAD method to nanophase diagrams and pressure phase diagrams. In this study, the phase diagram of an arbitrary A–B nanoparticle system under pressure was investigated. The effects of the interaction parameter and excess volume were investigated with increasing pressure. The eutectic temperature was found to decrease in most cases, except when the interaction parameter in the liquid was zero and that in the solid was positive, while the excess volume parameter of the liquid was positive. Under these conditions, the eutectic temperature increased with increasing pressure.

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Coupled Preparation of Ferronickel and Cementitious Material from Laterite Nickel Ores

Materials ◽

10.3390/ma13214992 ◽

2020 ◽

Vol 13 (21) ◽

pp. 4992

Author(s):

Ruimeng Shi ◽

Xiaoming Li ◽

Yaru Cui ◽

Junxue Zhao ◽

Chong Zou ◽

...

Keyword(s):

Direct Reduction ◽

Cementitious Materials ◽

Tricalcium Silicate ◽

Cementitious Material ◽

Raw Material ◽

Tricalcium Aluminate ◽

Thermodynamic Conditions ◽

Nickel Ores ◽

Main Components ◽

Factsage Software

Nickel slags can be produced through ferronickel preparation by the pyrometallurgical processing of laterite nickel ores; however, such techniques are underutilized at present, and serious environmental problems arise from the stockpiling of such nickel ores. In this study, a modification to the process of ferronickel preparation by the direct reduction of carbon bases in laterite nickel ores is proposed. The gangue from the ore is used as a raw material to prepare a cementitious material, with the main components of tricalcium silicate and tricalcium aluminate. By using FactSage software, thermodynamic calculations are performed to analyze the reduction of nickel and iron and the effect of reduction on the formation of tricalcium silicate and tricalcium aluminate. The feasibility of a coupled process to prepare ferronickel and cementitious materials by the direct reduction of laterite nickel ore and gangue calcination, respectively, is discussed under varying thermodynamic conditions. Different warming strategies are applied to experimentally verify the coupled reactions. The coupled preparation of ferronickel and cementitious materials with calcium silicate and calcium aluminate as the main phases in the same experimental process is realized.

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Octane Index Applicability over the Pressure-Temperature Domain

Energies ◽

10.3390/en14030607 ◽

2021 ◽

Vol 14 (3) ◽

pp. 607

Author(s):

Tommy R. Powell ◽

James P. Szybist ◽

Flavio Dal Forno Chuahy ◽

Scott J. Curran ◽

John Mengwasser ◽

...

Keyword(s):

High Efficiency ◽

National Laboratory ◽

Operating Conditions ◽

Dominant Factor ◽

Compression Ignition ◽

Oak Ridge ◽

Operating Modes ◽

Wide Range ◽

Thermodynamic Conditions ◽

Si Engines

Modern boosted spark-ignition (SI) engines and emerging advanced compression ignition (ACI) engines operate under conditions that deviate substantially from the conditions of conventional autoignition metrics, namely the research and motor octane numbers (RON and MON). The octane index (OI) is an emerging autoignition metric based on RON and MON which was developed to better describe fuel knock resistance over a broader range of engine conditions. Prior research at Oak Ridge National Laboratory (ORNL) identified that OI performs reasonably well under stoichiometric boosted conditions, but inconsistencies exist in the ability of OI to predict autoignition behavior under ACI strategies. Instead, the autoignition behavior under ACI operation was found to correlate more closely to fuel composition, suggesting fuel chemistry differences that are insensitive to the conditions of the RON and MON tests may become the dominant factor under these high efficiency operating conditions. This investigation builds on earlier work to study autoignition behavior over six pressure-temperature (PT) trajectories that correspond to a wide range of operating conditions, including boosted SI operation, partial fuel stratification (PFS), and spark-assisted compression ignition (SACI). A total of 12 different fuels were investigated, including the Co-Optima core fuels and five fuels that represent refinery-relevant blending streams. It was found that, for the ACI operating modes investigated here, the low temperature reactions dominate reactivity, similar to boosted SI operating conditions because their PT trajectories lay close to the RON trajectory. Additionally, the OI metric was found to adequately predict autoignition resistance over the PT domain, for the ACI conditions investigated here, and for fuels from different chemical families. This finding is in contrast with the prior study using a different type of ACI operation with different thermodynamic conditions, specifically a significantly higher temperature at the start of compression, illustrating that fuel response depends highly on the ACI strategy being used.

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Condensation/immersion mode ice-nucleating particles in a boreal environment

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-6687-2020 ◽

2020 ◽

Vol 20 (11) ◽

pp. 6687-6706

Author(s):

Mikhail Paramonov ◽

Saskia Drossaart van Dusseldorp ◽

Ellen Gute ◽

Jonathan P. D. Abbatt ◽

Paavo Heikkilä ◽

...

Keyword(s):

Field Campaign ◽

Particle Species ◽

Entire Field ◽

Time Period ◽

Regional Sources ◽

Range Transport ◽

Thermodynamic Conditions ◽

Set Up ◽

Boreal Environment ◽

Measurement Location

Abstract. Ice-nucleating particle (INP) measurements were performed in the boreal environment of southern Finland at the Station for Measuring Ecosystem–Atmosphere Relations (SMEAR II) in the winter–spring of 2018. Measurements with the Portable Ice Nucleation Chamber (PINC) were conducted at 242 K and 105 % relative humidity with respect to water. The median INP number concentration [INP] during a 6-week measurement period was 13 L−1. The [INP] spanned 3 orders of magnitude and showed a general increase from mid-February until early April. No single dominant local or regional sources of INPs in the boreal environment of southern Finland could be identified. Rather, it is hypothesised that the INPs detected at SMEAR II are a result of long-range transport and dilution of INPs sourced far from the measurement site. Despite high variability, the measured [INP] values fall within the range expected for the [INP] measured elsewhere under similar thermodynamic conditions. The [INP] did not correlate with any of the examined parameters during the entire field campaign, indicating that no one single parameter can be used to predict the [INP] at the measurement location during the examined time period. The absence of a correlation across the entire field campaign also suggests that a variety of particles act as INPs at different times, although it was indirectly determined that ambient INPs are most likely within the size range of 0.1–0.5 µm in diameter on average. On shorter timescales, several particle species correlated well with the [INP]. Depending on the meteorological conditions, black carbon (BC), supermicron biological particles and sub-0.1 µm particles, most likely nanoscale biological fragments such as ice-nucleating macromolecules (INMs), correlated with the INP signal. However, an increase in the concentration of any of these particle species may not necessarily lead to the increase in the [INP]; the reasons for this remain unknown. Limitations of the instrumental set-up and the necessity for future field INP studies are addressed.

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Physical-Chemical and Thermodynamic Analyses of Ethanol Steam Reforming for Hydrogen Production

Journal of Fuel Cell Science and Technology ◽

10.1115/1.2217957 ◽

2006 ◽

Vol 3 (3) ◽

pp. 346-350 ◽

Cited By ~ 11

Author(s):

Antonio Carlos Caetano de Souza ◽

José Luz-Silveira ◽

Maria Isabel Sosa

Keyword(s):

Hydrogen Production ◽

Steam Reforming ◽

Production Efficiency ◽

Physical Chemical ◽

Steam Reforming Of Ethanol ◽

Thermodynamic Conditions ◽

High Production ◽

Exergetic Analysis ◽

Global Reaction ◽

Technical Features

Steam reforming is the most usual method of hydrogen production due to its high production efficiency and technological maturity. The use of ethanol for this purpose is an interesting option because it is a renewable and environmentally friendly fuel. The objective of this article is to present the physical-chemical, thermodynamic, and exergetic analysis of a steam reformer of ethanol, in order to produce 0.7Nm3∕h of hydrogen as feedstock of a 1kW PEMFC. The global reaction of ethanol is considered. Superheated ethanol reacts with steam at high temperatures producing hydrogen and carbon dioxide, depending strongly on the thermodynamic conditions of reforming, as well as on the technical features of the reformer system and catalysts. The thermodynamic analysis shows the feasibility of this reaction in temperatures about 206°C. Below this temperature, the reaction trends to the reactants. The advance degree increases with temperature and decreases with pressure. Optimal temperatures range between 600 and 700°C. However, when the temperature attains 700°C, the reaction stability occurs, that is, the hydrogen production attains the limit. For temperatures above 700°C, the heat use is very high, involving high costs of production due to the higher volume of fuel or electricity used. The optimal pressure is 1atm., e.g., at atmospheric pressure. The exergetic analysis shows that the lower irreversibility is attained for lower pressures. However, the temperature changes do not affect significantly the irreversibilities. This analysis shows that the best thermodynamic conditions for steam reforming of ethanol are the same conditions suggested in the physical-chemical analysis.

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