scholarly journals Analyzing the Formation of Gaseous Emissions during Aluminum Melting Process with Utilization of Oxygen-Enhanced Combustion

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 242
Author(s):  
Róbert Dzurňák ◽  
Augustín Varga ◽  
Gustáv Jablonský ◽  
Miroslav Variny ◽  
Marcel Pástor ◽  
...  
Keyword(s):  
Ghg Emissions ◽  
Melting Process ◽  
Furnace Productivity ◽  
Melting Time ◽  
Gaseous Emissions ◽  
Cfd Simulations ◽  
Fuel Savings ◽  
Uniform Temperature Field ◽  
Mixing Patterns ◽  
Fuel Burner

Oxygen-enhanced combustion (OEC) is a useful method for improving the efficiency of thermal plants and for decreasing greenhouse gas (GHG) emissions. Basic and modified burner designs utilizing OEC in the aluminum melting process in a rotary tilting furnace were studied. A combined approach comprising experimental measurement and simulation modeling was adopted aimed at assessing GHG emissions production. Reduction of up to 60% fuel consumption of the total natural gas used in the laboratory-scale furnace was achieved. The optimal oxygen concentration in the oxidizer regarding the amount of total GHG emissions produced per charge expressed as CO2 equivalent was 35% vol. Its further increase led only to marginal fuel savings, while the nitrogen oxide emissions increased rapidly. Using the modified burner along with OEC led to around 10% lower CO2 emissions and around 15% lower total GHG emissions, compared to using a standard air/fuel burner. CFD simulations revealed the reasons for these observations: improved mixing patterns and more uniform temperature field. Modified burner application, moreover, enables furnace productivity to be increased by shortening the charge melting time by up to 16%. The presented findings demonstrate the feasibility of the proposed burner modification and highlight its better energy and environmental performance indicators, while indicating the optimal oxygen enrichment level in terms of GHG emissions for the OEC technology applied to aluminum melting.

scholarly journals Evaluation of a Novel Poultry Litter Amendment on Greenhouse Gas Emissions

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 563
Author(s):  
Kelsey Anderson ◽  
Philip A. Moore ◽  
Jerry Martin ◽  
Amanda J. Ashworth
Keyword(s):  
Air Quality ◽  
Greenhouse Gas ◽  
Co2 Emissions ◽  
Management Practices ◽  
Block Design ◽  
Poultry Litter ◽  
Ghg Emissions ◽  
Nitrous Oxide Emissions ◽  
Gaseous Emissions ◽  
Poultry Facilities

Gaseous emissions from poultry litter causes production problems for producers as well as the environment, by contributing to climate change and reducing air quality. Novel methods of reducing ammonia (NH3) and greenhouse gas (GHG) emissions in poultry facilities are needed. As such, our research evaluated GHG emissions over a 42 d period. Three separate flocks of 1000 broilers were used for this study. The first flock was used only to produce litter needed for the experiment. The second and third flocks were allocated to 20 pens in a randomized block design with four replicated of five treatments. The management practices studied included an unamended control; a conventional practice of incorporating aluminum sulfate (referred to as alum) at 98 kg/100 m2); a novel litter amendment made from alum mud, bauxite, and sulfuric acid (alum mud litter amendment, AMLA) applied at different rates (49 and 98 kg/100 m2) and methods (surface applied or incorporated). Nitrous oxide emissions were low for all treatments in flocks 2 and 3 (0.40 and 0.37 mg m2 hr−1, respectively). The formation of caked litter (due to excessive moisture) during day 35 and 42 caused high variability in CH4 and CO2 emissions. Alum mud litter amendment and alum did not significantly affect GHGs emissions from litter, regardless of the amendment rate or application method. In fact, litter amendments such as alum and AMLA typically lower GHG emissions from poultry facilities by reducing ventilation requirements to maintain air quality in cooler months due to lower NH3 levels, resulting in less propane use and concomitant reductions in CO2 emissions.

Testing the Performance of a Traditional Furnace Melting Process on Bronze as the Material of Gamelan

2017 ◽  
Vol 889 ◽  
pp. 99-103
Author(s):  
I. Gusti Ngurah Priambadi ◽  
I. Ketut Gede Sugita
Keyword(s):  
Melting Furnace ◽  
Melting Process ◽  
Data Retrieval ◽  
Musical Instrument ◽  
Smelting Process ◽  
Melting Time ◽  
Time Data ◽  
Average Temperature ◽  
Furnace Melting ◽  
Low Efficiency

Gamelan is traditional musical instrument that evolves especially in Bali, its function is to accompany the religious and cultural ceremonies of Hindus. The making process of gamelan, smelting bronze alloys, is done by using traditional furnaces. The use of charcoal as fuel in smelting process causes melting furnace performance is difficult to determine. That condition impacts the effectiveness of the smelting process especially in determining the needs of fuel and the processing time. Therefore, it influences the productivity of crafters. This research was conducted to test the performance of the furnace in accordance with a design that is commonly used by artisans. The observation was done at the temperature of melting, melting time, data retrieval was conducted repeatedly three times on different days. Based on the analysis and observation in accordance with the experimental design made whereby in the smelting process to achieve the casting temperature indicated as follows. The average temperature of smelting is 730,8 °C, fuel use is 23 kg, melting time is 39.76 minutes as well as the efficiency of the furnace 36.80%. Based on the analysis conducted, low efficiency is due to the surface of the furnace which is designed open, so that during the energy generated in the process of burning a lot of fuel wasted into the environment.

scholarly journals Numerical Modeling of the Melting Process in a Shell and Coil Tube Ice Storage System for Air-Conditioning Application

2019 ◽  
Vol 9 (13) ◽  
pp. 2726 ◽  
Author(s):  
Seyed Soheil Mousavi Ajarostaghi ◽  
Sébastien Poncet ◽  
Kurosh Sedighi ◽  
Mojtaba Aghajani Delavar
Keyword(s):  
Heat Transfer ◽  
Numerical Modeling ◽  
Energy Storage ◽  
Cold Storage ◽  
Air Conditioning ◽  
Storage System ◽  
Melting Process ◽  
Melting Time ◽  
Inlet Temperature ◽  
Geometrical Parameters

Cold thermal energy storage, as a promising way of peak-shifting, can store energy by using cheap electricity during off-peak hours and regenerate electricity during peak times to reduce energy consumption. The most common form of cold storage air conditioning technology is ice on the coil energy storage system. Most of the previous studies so far about ice on coil cold storage system have been done experimentally. Numerical modeling appears as a valuable tool to first better understand the melting process then to improve the thermal performance of such systems by efficient design. Hence, this study aims to simulate the melting process of phase change materials in an internal melt ice-on-coil thermal storage system equipped with a coil tube. A three-dimensional numerical model is developed using ANSYS Fluent 18.2.0 to evaluate the dynamic characteristics of the melting process. The effects of operating parameters such as the inlet temperature and flowrate of the heat transfer fluid are investigated. Also, the effects of the coil geometrical parameters—including coil pitch, diameter, and height—are also considered. Results indicate that conduction is the dominant heat transfer mechanism at the initial stage of the melting process. Increasing either the inlet temperature or the flowrate shortens the melting time. It is also shown that the coil diameter shows the most pronounced effect on the melting rate compared to the other investigated geometrical parameters.

scholarly journals NUMERICAL STUDY OF THE GEOMETRIC INFLUENCE OF A FIN IN A CYLINDRICAL HEAT EXCHANGER FOR MELTING OF PCM

2019 ◽  
Vol 18 (1) ◽  
pp. 78
Author(s):  
F. C. Spengler ◽  
B. Oliveira ◽  
R. C. Oliveski ◽  
L. A. O. Rocha
Keyword(s):  
Heat Exchanger ◽  
Aspect Ratio ◽  
Phase Change ◽  
Latent Heat ◽  
Heat Storage ◽  
Numerical Study ◽  
Melting Process ◽  
High Energy ◽  
High Energy Density ◽  
Melting Time

The thermal heat storage it’s an effective way to suit the energy availability with the demand schedule. It can be stored in the means of sensible or latent heat, the latter applying a material denominated Phase Change Material (PCM), which is provided as organic compounds, hydrated salts, paraffins, among others. The latent heat storage systems offer several advantages, like the practically isothermal process of loading and unloading and the high energy density. However, the low thermal conductivity makes the cycle prolonged on these systems, restricting its applicability. Applying computational fluid dynamics, the behavior of the PCM melting process was studied in cylindrical cavities with horizontal and vertical fins, aiming the optimization of the fin geometry. In this way the fin area was kept constant, varying its aspect ratio. The numerical model was validated with results from the literature and it’s composed of the continuity, momentum and energy equations increased by the phase change model. Qualitative and quantitative results are presented, referring to mesh independence, contours of velocity, net fraction and temperature at different moments of the process. The results of the study indicate that the position of the fin in the heat exchanger influences the melting process, although the vertical fins have a faster total melting process, horizontal fins can reach larger partial liquid fractions in less time in the heat exchanger. Such as the position of the fin, the increase of its length propitiates the reduction of the melting time, evidencing the optimal aspect ratio.

scholarly journals An earth system model shows self-sustained melting of permafrost even if all man-made GHG emissions stop in 2020

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jorgen Randers ◽  
Ulrich Goluke
Keyword(s):  
Water Vapour ◽  
Surface Albedo ◽  
Climate Model ◽  
Ghg Emissions ◽  
Melting Process ◽  
The Arctic ◽  
Physical Processes ◽  
The World ◽  
Point Of No Return ◽  
Arctic Ice

AbstractThe risk of points-of-no-return, which, once surpassed lock the world into new dynamics, have been discussed for decades. Recently, there have been warnings that some of these tipping points are coming closer and are too dangerous to be disregarded. In this paper we report that in the ESCIMO climate model the world is already past a point-of-no-return for global warming. In ESCIMO we observe self-sustained melting of the permafrost for hundreds of years, even if global society stops all emissions of man-made GHGs immediately. We encourage other model builders to explore our discovery in their (bigger) models, and report on their findings. The melting (in ESCIMO) is the result of a continuing self-sustained rise in the global temperature. This warming is the combined effect of three physical processes: (1) declining surface albedo (driven by melting of the Arctic ice cover), (2) increasing amounts of water vapour in the atmosphere (driven by higher temperatures), and (3) changes in the concentrations of the GHG in the atmosphere (driven by the absorption of CO2 in biomass and oceans, and emission of carbon (CH4 and CO2) from melting permafrost). This self-sustained, in the sense of no further GHG emissions, melting process (in ESCIMO) is a causally determined, physical process that evolves over time. It starts with the man-made warming up to the 1950s, leading to a rise in the amount of water vapour in the atmosphere—further lifting the temperature, causing increasing release of carbon from melting permafrost, and simultaneously a decline in the surface albedo as the ice and snow covers melts. To stop the self-sustained warming in ESCIMO, enormous amounts of CO2 have to be extracted from the atmosphere.

Experimental and Theoretical Study on Melting Kinetics of Spherical Aluminum Particles in Liquid Aluminum

2015 ◽  
Vol 1765 ◽  
pp. 139-144
Author(s):  
Marco Ramírez-Argáez ◽  
Enrique Jardón ◽  
Carlos González-Rivera
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Transfer Coefficient ◽  
Process Analysis ◽  
Convective Heat Transfer Coefficient ◽  
Melting Process ◽  
Solid Particles ◽  
Melting Time ◽  
Melting Kinetics ◽  
Kinetics Of

ABSTRACTIn this study a process analysis of the melting process of solid particles in a bath of same composition is performed using both experimental information and theoretical computations. An experimental setup was used to measure the thermal histories and to follow the evolution with time of the size of solid metallic spherical particles being melted in a metallic bath of same composition. For such a purpose, pure aluminum was used during the experiments for both solid particles and liquid bath. A mathematical model was also developed based on first principles of heat transfer to simulate the melting kinetics of a cold metallic spherical particle immersed in a hot liquid bath of same composition. The mathematical model was reasonably validated when compared against the experimental results obtained in this work. A process analysis of the melting process was performed to determine the effect of the initial temperature and size of the solid particle, the bath temperature and the convective heat transfer coefficient on the melting time and on the energy consumption.The analysis showed that the variable presenting the most significant effect on both the melting time and the energy consumption is the convective heat transfer coefficient between the particle and the bath, since an increment in such a parameter accelerates the melting process and saves energy. Therefore, proper stirring of the bath is highly recommended to enhance the melting of metallic alloying additions in the metallic baths.

Influence of Aeration on NH3, CH4 and N2O Emissions during Kitchen Waste Composting

2013 ◽  
Vol 864-867 ◽  
pp. 1904-1908
Author(s):  
Hong Yu Zhang ◽  
Guo Xue Li ◽  
Hong Fei Wei
Keyword(s):  
Greenhouse Gases ◽  
Ghg Emissions ◽  
Great Influence ◽  
Gaseous Emissions ◽  
Kitchen Waste ◽  
Compact Structure ◽  
Continuous Measurements ◽  
Aeration System ◽  
Ghg Reduction ◽  
Forced Aeration

Because of high moisture content and compact structure, composting kitchen waste would discharge by-products such as leachate, ammonia (NH3), and greenhouse gases, and these can cause secondary environmental pollution. In this study, continuous measurements of gas emissions were carried out and detailed gas emission patterns were obtained using forced aeration system at aerations of 2·10-4 (T1), 4·10-4 (A2) and 6·10-4 ( (A3) m3·kgDM-1·min-1. During the experiment, temperature and oxygen content were determined, and continuous measurements of NH3 and gaseous emissions (CH4, N2O, and NH3) were taken. The results indicated that the aeration had a significant effect on NH3, CH4 and N2O emission (p<0.05). The highest concentration of NH3, CH4 and N2O were all observed in the treatment of T2. The productions of NH3 were reduced by 59.6% and 33.7%, and greenhouse gases (GHG) were reduced by 50.8% and 40.5% for T1 and T2 that compared to T3, respectively. Obviously, the aeration has great influence on NH3 and GHG emissions. In this study, the aeration was 2·10-4 m3·kgDM-1·min-1 in favor of NH3 and GHG reduction.

scholarly journals Melting process modeling of Carreau non-Newtonian phase- change material in dual porous vertical concentric cylinders

2020 ◽  
pp. 329-329
Author(s):  
Mohsen Talebzadegan ◽  
Mojtaba Moravej ◽  
Ehsanolah Assareh ◽  
Mohsen Izadi
Keyword(s):  
Porous Media ◽  
Rayleigh Number ◽  
Phase Change ◽  
Phase Change Material ◽  
Melting Process ◽  
Darcy Number ◽  
Melting Time ◽  
Stefan Number ◽  
Concentric Cylinders ◽  
Change Material

In this paper a numerical simulation of the melting process of Carreau non- Newtonian phase-change material (PCM) inside two porous vertical concentric cylinders included constant temperatures of the inner and outer walls, represented by Th and Tc respectively. Half of the void between the two pipes is filled with copper porous media and paraffin wax as a phase change material. The governing equations are converted into a dimentionless form and are solved using the finite element method. The enthalpy- porosity theory is applied to simulate the phase change of PCM while the porous media follow to the Darcy law. Outcomes are shown and compared in terms of the streamline, isotherm, melting fraction and mean Nusselt numbers. The solid- liquid interface location and the temperature distribution are predicted to describe the melting process. The effects of the Carreau index, porosity and non-dimensional parameters such as Stefan number, Darcy number and Rayleigh number are analyzed. Our results indicate a good agreement between this study and the previous investigations. The results show that an increase in Rayleigh number, Stefan number and Darcy number increases the melting volume fraction and reduces the melting time. Also, the time of melting non-Newtonian phase change material decreases when Carreau index and porosity decrease.

scholarly journals Role of honeycomb structure in improving the melting process of a phase change material inside a latent heat storage unit

2021 ◽  
Vol 19 ◽  
pp. 589-592
Author(s):  
M. Hariss ◽  
◽  
M. El Alami ◽  
A. Gounni
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Numerical Study ◽  
Melting Process ◽  
Honeycomb Structure ◽  
Melting Time ◽  
Storage Unit ◽  
Latent Heat Storage ◽  
The Impact

In this work, a numerical study is performed to analyze the impact of honeycomb structure on heat transfer within the PCM. The modeling is based on a transient calculation making it possible to analyze the phase change of the paraffin using the commercial software "Fluent" based on the enthalpy-porosity model. The results showed that the impregnation of a metal matrix in a rectangular enclosure helps to decrease the melting time and thus improve the heat transfer within the PCM.

scholarly journals Electric Field Interaction with Hydrocarbon Flames

2018 ◽  
Vol 63 (5) ◽  
pp. 402
Author(s):  
S. G. Orlovskaya ◽  
M. S. Skoropado ◽  
F. F. Karimova ◽  
V. Ya. Chernyak ◽  
L. Yu. Vergun
Keyword(s):  
Melting Point ◽  
Field Strength ◽  
Electric Field ◽  
Fossil Fuels ◽  
Melting Process ◽  
Melting Rate ◽  
Melting Time ◽  
Field Interaction ◽  
Hydrocarbon Flames ◽  
Dc Electric Field

The problem of electric-field-assisted combustion for low-melting point hydrocarbons (paraffin wax, n-alkanes) attracts the attention of scientists in relation to the development of paraffin-based propellants. Our study is aimed at the detailed investigation of the dc electric field interaction with the flame of octadecane droplet. We have studied the melting and combustion of alkane particles in the electric field ranging from 33 kV/m to 117 kV/m. It is found that the melting rate decreases distinctly starting with the electric field strength E ∼ 80 kV/m. This effect is more pronounced at high gas temperatures (Ste >1), when the melting time is about a few seconds. So, the melting process slows down in the dc electric field. At the same time, the burning rate constant rises by more than 10 percents. The obtained results can be used to develop efficient and clean technologies of fossil fuels combustion.

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