The Need of Performing an Energy Audit in a Metallurgical Industry: A Case Study of The Ajaokuta Foundry Shop

The research work focuses on the need to perform an energy audit in a metallurgical industry concerning the operations of the Foundry Shop of the Ajaokuta Steel Company Limited. Some basic components for performing the energy audits were discussed. The foundry processes and operations are based on the production of components for other basic industries where their components are used for manufacturing processes like the quarry industries, battery industries, manufacturing, and other process industries. To produce the desired components that the vessel used for the production processes like the Electric Arc Furnaces, the Induction furnace, the crucible furnace, and centrifugal furnaces must be utilized for the effective and optimal production processes tHrough constant monitoring and sustenance of the energy used during the production process. To achieve these production processes, there is always a need to perform energy audits of the facilities used. One method is to design methods of monitoring the power consumed per heat cycle, the duration taken for the production cycle to be completed, and cost expenditure. The need of performing research work was due to the anomalies observed during the melting processes of the two furnaces, the six-tonne Electric Arc Furnace and the One-tonne induction furnace. It was observed that the melting cycle of 2½ to 3 hours was not maintained rather more time, more energy, and more money are wasted on every melting process. To put these situations to check the production processes for the two furnaces were monitored from 5/10/ 2006 to 21/11/2007 for the Six tonnes capacity Electric Arc Furnace and from 03/06/2005 to 01/08/2007 respectively. The data generated were used for the analytical processes of the energy audits. Methods of presenting energy reports and energy action plans were brought to the fore. The performance of the energy audits indicated that much energy was consumed, more time was taken for completing a melting cycle as against the standard while a lot of money is being wasted whenever production processes take place.

Shear Strength Deterioration Effect and Slope Reliability Analysis Under Extreme Ice-snow Melting Conditions

Extreme ice-snow melting in winter affects the infiltration process of snow water on the slope surface significantly, and plays an important role in the deformation stability of landslide. The fluctuation trend of slope stability under ice-snow melting is the same as that of soil volume water content. The deterioration effect of mechanical parameters will directly affect the deformation stability of bank slope. Based on this, the ice-snow melting cycle model test of slope soil was designed and carried out. The results are showed.(1) We were established an ice-snow melting model based on physical process. In the process of ice-snow melting, the soil cohesion and internal friction Angle have obvious deterioration effect .The deterioration of cohesion is obviously larger than that of internal friction Angle. In the early part of the ice-snow melting cycle, the deterioration of shear strength parameters is very obvious. Among them, the deterioration of shear strength parameters caused by the first four ice-snow melting cycles accounted for about 70% of the total deterioration. After the G2/T2 ice-snow melting cycle, the degree of phase deterioration gradually decreases. The deterioration trend of shear parameters of soil samples gradually tends to be gentle. (2) In the ice-snow melting cycle, the inside of the soil samples have micro-cracks, fissures repeatedly opened and closed, gradually developed and converged. The result is that the soil samples change from dense state to loose state where internal cracks develop. The internal damage of soil samples is the fundamental reason for the gradual deterioration of shear strength.（3）We are keep to the relative independence principle of creep model and unsaturated seepage equation. We are studied and improved the parameter solving method of creep model. The modified model is reasonable and effective. The creep trend and main characteristics of the unsaturated soil can be described well. Shear strength deterioration effect and slope reliability analysis under extreme ice-snow melting conditions .It has important reference significance to the protection of extreme snow and ice disaster on the bank slope.

Maximizing the Productivity of a Gas Melting Furnace with Regard to the Ecological Efficiency of its Operation

Due to the implementation of environmental regulations and the continual tightening up of the limits for pollutants in combustion systems, we are being forced to pay more attention to this area. A significant source of pollutants originating from the industry is, in particular, the formation of carbon dioxide (CO2) and nitrogen oxides (NOx) in combustion systems with air intake. The control of pollutant emissions has become a global concern due to the worldwide increase in the use of fossil fuels. Besides the fact that the insufficient combustion process has a significant share of emissions in the environment, it also reduces the overall efficiency and economy of the operation using this energy source. We encounter this problem also in the operation of gas melting furnaces. Therefore, the aim of this paper was to describe the results of experimental measurements of the amount of emissions produced during the gas melting furnace KOV 010/1998 operation, which is in practice predominantly used for the melting of Aluminium alloys. Experimental measurements were performed to design the most appropriate operating mode variant of the melting furnace with regard to maximizing its productivity and at the same time to minimizing the total amount of emissions produced during one melting cycle.

Analysis of the Thermal Transfers in a VASM Crucible: Electron Beam Melting Experiment and Numerical Simulation

A description of the Vacuum Arc Skull Melting (VASM) process is presented showing its particularly complex features because of the mixing of porous raw materials with the dense remelted metal as well as the very high temperature and the highly transient nature of the process. This paper presents a 3D transient mathematical modelling of the heat transport with the aim of bringing a better understanding of the thermal behavior of the material into the crucible during a melting cycle. The model takes into account the heat input provided by the incoming metal thanks to an adaptive meshing, as well as the latent heat of solidification and the radiative heat transfers. An experimental validation of the model is presented where an electron beam heating source mimics the heat effect of the arc thanks to an excellent guidance of the beam over the melt surface. A comparison between the measured and calculated temperatures of a steel load is reported and reveals a satisfactory agreement. With very few adjustments, concerning mainly heat radiation at the top surface of metal into the crucible, the numerical model appears to be an efficient numerical tool to simulate the VASM process at the industrial scale.

Using animations in identifying general chemistry students' misconceptions and evaluating their knowledge transfer relating to particle position in physical changes

This article reports on the types of views and misconceptions uncovered after assessing 155 freshman general chemistry students on the concept of particle position during the reversible physical change of melting, using the Melting Cycle Instrument, which illustrates particulate-level representations of a melting–freezing cycle. Animations involving particulate-level representations of phase changes including melting and freezing were viewed and discussed, and the students were assessed a second time, on the concept of particle position during the reversible physical change of dissolving, using the Dissolving Cycle Instrument, which illustrates particulate-level representations of a dissolving-solvent evaporation cycle. Overall, the results of the assessments showed that some misconceptions did remain after viewing and discussing the animations, and that the use of the animations had no effect on the students' views on the movement of particles within the liquid.

Phase Transition of Water Confined in Saponites Using Positron Annihilation Spectroscopy

The temperature dependent Positron lifetime and Doppler broadening spectroscopy have been carried out to study the phase transition of water confined in interlamellar spaces of saponite clay in the temperature range 300K-200K. The change in slope/discontinuity in S-parameter and Ps lifetime as a function of temperature is an indication of phase transition. Two phase transition temperatures viz. above and below the bulk freezing temperature have been observed for water confined in saponite clay. This indicates the presence of two regimes of water confined in interlamellar spaces. The freezing-melting cycle is also marked by significant hysteresis.

Growth of melt–freeze clusters and formation of impeding layers to water flow in snow irradiated by a sun simulator under controlled laboratory conditions

Stratigraphic boundaries at fine-to-coarse transitions in snow can introduce impeding layers to infiltrating water. In our present investigation, such impeding horizons were observed within sub-freezing homogeneous snow as a consequence of subsurface melting caused by the penetration of solar radiation. This new texture impeded the further downward flow of meltwater at fine-to-coarse transitions, leading to the formation of low-permeability melt–freeze crusts following multiple melt–freeze cycles. In this work, a large sub-freezing (–6°C) homogeneous sample, consisting of small rounded grains, was periodically exposed to intense radiation generated by a sun simulator. Due to the penetration of shortwave radiation into the snow, subsurface melting caused the growth of melt–freeze polycrystals from clustered rounded crystals. Variations in mass growth (%) of melt–freeze polycrystals and mass loss (%) of grain clusters were studied within the sub-freezing snow with respect to different melt–freeze cycles. In this work, we study the growth of melt–freeze polycrystals in the top and bottom sub-layers with respect to collective saturation. Saturation profiles from the snow were recorded with a parallel-probe saturation profiler (PPSP) device, sampling at vertical intervals of 7mm, after each melting cycle. Intrinsic permeabilities across different stratified sub-layers were monitored in relation to saturation as a function of different melt–freeze cycles. Our observations revealed that there is a significant decrease in intrinsic permeability for the first few top sub-layers. Also, permeability in the second topmost sub-layer was less than that in the topmost sub-layer directly interacting with the radiation. These results support the evolution of a new coarse grain texture within the homogeneous snow that subsequently converts into a layer of low permeability. In the various transects of the snow sample, two melt–freeze crusts and one ice crust were manually identified through stratigraphic mapping. A correlation was also established between the saturation spikes recorded with the help of the PPSP and corresponding depth positions of the crusts.