Designing and assessing a novel vertical vibrated particle separator

Uncontrolled segregation in particulate mixtures has long been considered as an annoying, and costly, feature encountered in many materials handling operations and although the onset is not clear, many believe it to be driven by the differences in particulate physical properties. An increasing number of usefully scaled laboratory and computer simulation investigations are being carried, particularly by the physics community, to help our understanding of this phenomenon. Physicists at the University of Nottingham have identified that through careful control of frequency and acceleration during vertical vibration, different types of particles can be positioned and/or segregated in a small rectangular cell. An extension of this work resulted in the design of a new small scale batch separator capable of recovering at least one separated particle layer in a different chamber. This work has explored the scale up of the small particle separator to operate in a semi-continuous mode. Since complete experimental know how of particle segregation phenomena is still deficient an empirical design strategy was used. This scaled up particle separator was driven by a pneumatically powered vertical vibration bench in which dry, non-cohesive particulate mixtures of varying densities and sizes (<1000µm) were vertically vibrated under different conditions to assess their separation behaviours. Experiments with regular (e.g. glass and bronze) and irregular shaped particle mixtures (e.g. comminuted glass and bronze) showed that lower magnitudes of vertical vibration frequency (30±10%), dimensionless acceleration (3±10%), particle bed heights (20 and 40mm in majority of the investigated cases) and partition gap sizes (5 and 10mm) were important for separation. Finally, the technique was employed to separate various industrially relevant particle mixtures (shredded printed circuit boards, iridium and aluminium oxide and shredded personal computer wires). Two-dimensional Discrete Element Modelling (DEM) with interstitial fluid interactions simulated with a maximum of 1000 virtual glass and bronze particles showed some important aspects of particle segregation such as; layered particle separation, high density particles ending on top and bottom of the particle bed, convection currents, particle bed tilting and partitioned particle separation. The application of Positron Emission Particle Tracking (PEPT) to glass, bronze, ilmenite and sand particles showed distinct trajectory maps in three dimension (X,Y and Z) with varying particle speeds in the vertically vibrated particle mixtures. The low density particles were mostly observed to move in the middle while the high density particles patrolled in the outer periphery of the separation cell. These distinct particle motions suggested that convection currents played an important role in controlling segregation. Furthermore, the application of a smoke blanket visualization technique showed the existence of air convection currents on top of the vertically vibrating particle mixtures. The experiments on the scaled up semi-continuous particle separator confirmed what was identified previously in that good particle separation could be achieved through careful control of the frequency and acceleration during vertical vibration. This information lays the foundations for a new breed of low cost, dry separator for fine particulate mixtures. Key Words: Vertical vibration, particle separator, fine particle mixtures, dry separation, PEPT, DEM, smoke visualizations

Designing and assessing a novel vertical vibrated particle separator

Uncontrolled segregation in particulate mixtures has long been considered as an annoying, and costly, feature encountered in many materials handling operations and although the onset is not clear, many believe it to be driven by the differences in particulate physical properties. An increasing number of usefully scaled laboratory and computer simulation investigations are being carried, particularly by the physics community, to help our understanding of this phenomenon. Physicists at the University of Nottingham have identified that through careful control of frequency and acceleration during vertical vibration, different types of particles can be positioned and/or segregated in a small rectangular cell. An extension of this work resulted in the design of a new small scale batch separator capable of recovering at least one separated particle layer in a different chamber. This work has explored the scale up of the small particle separator to operate in a semi-continuous mode. Since complete experimental know how of particle segregation phenomena is still deficient an empirical design strategy was used. This scaled up particle separator was driven by a pneumatically powered vertical vibration bench in which dry, non-cohesive particulate mixtures of varying densities and sizes (<1000µm) were vertically vibrated under different conditions to assess their separation behaviours. Experiments with regular (e.g. glass and bronze) and irregular shaped particle mixtures (e.g. comminuted glass and bronze) showed that lower magnitudes of vertical vibration frequency (30±10%), dimensionless acceleration (3±10%), particle bed heights (20 and 40mm in majority of the investigated cases) and partition gap sizes (5 and 10mm) were important for separation. Finally, the technique was employed to separate various industrially relevant particle mixtures (shredded printed circuit boards, iridium and aluminium oxide and shredded personal computer wires). Two-dimensional Discrete Element Modelling (DEM) with interstitial fluid interactions simulated with a maximum of 1000 virtual glass and bronze particles showed some important aspects of particle segregation such as; layered particle separation, high density particles ending on top and bottom of the particle bed, convection currents, particle bed tilting and partitioned particle separation. The application of Positron Emission Particle Tracking (PEPT) to glass, bronze, ilmenite and sand particles showed distinct trajectory maps in three dimension (X,Y and Z) with varying particle speeds in the vertically vibrated particle mixtures. The low density particles were mostly observed to move in the middle while the high density particles patrolled in the outer periphery of the separation cell. These distinct particle motions suggested that convection currents played an important role in controlling segregation. Furthermore, the application of a smoke blanket visualization technique showed the existence of air convection currents on top of the vertically vibrating particle mixtures. The experiments on the scaled up semi-continuous particle separator confirmed what was identified previously in that good particle separation could be achieved through careful control of the frequency and acceleration during vertical vibration. This information lays the foundations for a new breed of low cost, dry separator for fine particulate mixtures. Key Words: Vertical vibration, particle separator, fine particle mixtures, dry separation, PEPT, DEM, smoke visualizations

Production of Indigenous and Enriched Khyber Pakhtunkhwa Coal Briquettes: Combustion and Disintegration Strength Analysis

Khyber Pakhtun Khwa province of Pakistan has considerable amounts of low ranked coal. However, due to the absence of any centrally administered power generation system there is a need to explore indigenous methods for effectively using this valuable energy resource. In the present study an indigenous coal briquetting technology has been developed and evaluated in terms of combustion characteristics such as moisture content, volatile matter, ash, fixed carbon and calorific value of the resulting coal briquette and disintegration strength using polyvinyl acetate (PVA) in combination with calcium carbonate (sample no 3 with highest disintegration strength value of 2059N). Comparison of test samples with the commercially available coal briquettes revealed improved combustion characteristics for the PVA bonded (sample no 1 and 5) coal briquettes having higher fixed carbon content and calorific value, lower ash contents as well as lower initial ignition time

Optimizing the Air Conditioning Layouts of an Indoor Built Environment:Towards the Energy and Environmental Benefits of a Clean Room

Reducing energy consumption in buildings has received intensified research impetus since the introduction of the decarbonization goals set in the Paris agreement. Many domestic and specialized applications require clean rooms (indoor built environments) for safe and clean operation. Energy efficiency in clean room spaces depends on maintaining livable or required conditions such as temperature, humidity, and particle concentration with minimal use of energy and new carbon dioxide (CO2) emissions. In the literature, parameters such as temperature, relative humidity, particle concentrations, and CO2 emissions are not able to be properly controlled in clean room systems. The designed system in the literature involves high energy consumption and high economic costs. All these factors add novelty to this research, which was a significant research gap in previous studies. This clean room is directly linked to environmental parameters such as ambient temperature, relative humidity, etc. The clean room is also related directly to the building and infrastructure in such a way that there are certain regulatory requirements for designing a clean room. For designing and constructing the controlled environment in a clean room, the English (EN) documents, ISO 9000, and various other standards allow for clean rooms for different types of products. In this research, the designed control configurations properly control the system. Additionally, this system is energy efficient, with positive environmental aspects regarding CO2 emissions. Three control configurations were designed in this research, option A, option B, and option C, and three parameters are controlled in the study. These parameters are room temperature, relative humidity, and CO2 emissions (outside the room). CO2 emissions are controlled outside the room (in the environment). In the last research phase, a comparative analysis of these three control configurations was performed to find an energy-efficient system with fewer CO2 emissions. Control configuration B (option B) provides reliable results regarding an energy-efficient system and fewer CO2 emissions emitted to the environment. In this study, an optimized configuration for the air conditioning system was developed for a clean room (volume 185.6 m3) with a required temperature of 23 °C, relative humidity of 40%, and a particle size of less than 0.3 μm. Three different design configurations were analyzed using TRNSYS simulation software. The minimization of energy use and CO2 emissions were the objective functions. Energy loads were calculated for each of the configurations by varying the fixed air change per hour and the minimum outdoor air flow rate. The results of a whole year simulation run for control configurations A, B, and show that, on the one hand, the ambient weather conditions of temperature and relative humidity (RH) is varied throughout year and, on the other hand, the clean room temperature was maintain at exactly 23 °C, which is the required set point temperature, for all the three configurations (A, B, and C). Furthermore, the clean room relative humidity was maintained at 36% for configuration A, below the 40% which was the set point for clean room relative humidity, and at 40% for configurations B and C. Configuration B exhibited the minimum energy use (7300 kWh), at a fixed air change per hour value of 20 and a minimum outdoor air flow rate of 150 L/s, with the least amount of CO2 emissions, offering an overall 25% improvement over configurations A and C

Compositional analysis of dark colored particulates homogeneously emitted with combustion gases (dark plumes) from brick making kilns situated in the area of Khyber Pakhtunkhwa, Pakistan

In Pakistan raw coal and a little quantity of waste plastics are burnt to sustain high temperature inside brick making kilns. The gaseous emissions of the kilns contain a considerable amount of darkish colored particulates. It is currently believed that the plastic burning produces these particulates. Advanced characterization instruments, such as a scanning electron microscope, energy dispersive spectroscopy, X-ray fluorescence, X-ray diffractometer, surface area analyzer using nitrogen gas adsorption isotherms, and thermogravimetric analyzer, were used to find out the chemistry and physics of the particulates. At a magnification of 30,000x, the SEM picture shows masses that are roughly roundish in shape and their size is in between 0.1 to 0.5 microns. The elements detected in these particles are carbon, oxygen, and sulfur (EDS analysis), or in other words, these elements are a typical composition of raw coal. This elemental analysis suggest that fine coal particles come out with usual combustion gases and these emitted particulates are not plastic combustion product. To strengthen this finding, the sample when calcined discarded a significant amount of sulphur oxides species, as determined in the XRF study by noticing a considerable decrease of sulphur content in the calcined particles, suggesting that the particles are actually a coal. The N2 isotherm graph reveals that the light weight flying coal particles has a very low surface area. Additionally, the XRD and TGA studies supports the conclusion that these dark colored particulate emissions are primarily fine coal particles (cenosphere)

Designing and assessing a novel vertical vibrated particle separator

Uncontrolled segregation in particulate mixtures has long been considered as an annoying, and costly, feature encountered in many materials handling operations and although the onset is not clear, many believe it to be driven by the differences in particulate physical properties. An increasing number of usefully scaled laboratory and computer simulation investigations are being carried, particularly by the physics community, to help our understanding of this phenomenon. Physicists at the University of Nottingham have identified that through careful control of frequency and acceleration during vertical vibration, different types of particles can be positioned and/or segregated in a small rectangular cell. An extension of this work resulted in the design of a new small scale batch separator capable of recovering at least one separated particle layer in a different chamber. This work has explored the scale up of the small particle separator to operate in a semi-continuous mode. Since complete experimental know how of particle segregation phenomena is still deficient an empirical design strategy was used. This scaled up particle separator was driven by a pneumatically powered vertical vibration bench in which dry, non-cohesive particulate mixtures of varying densities and sizes (<1000µm) were vertically vibrated under different conditions to assess their separation behaviours. Experiments with regular (e.g. glass and bronze) and irregular shaped particle mixtures (e.g. comminuted glass and bronze) showed that lower magnitudes of vertical vibration frequency (30±10%), dimensionless acceleration (3±10%), particle bed heights (20 and 40mm in majority of the investigated cases) and partition gap sizes (5 and 10mm) were important for separation. Finally, the technique was employed to separate various industrially relevant particle mixtures (shredded printed circuit boards, iridium and aluminium oxide and shredded personal computer wires). Two-dimensional Discrete Element Modelling (DEM) with interstitial fluid interactions simulated with a maximum of 1000 virtual glass and bronze particles showed some important aspects of particle segregation such as; layered particle separation, high density particles ending on top and bottom of the particle bed, convection currents, particle bed tilting and partitioned particle separation. The application of Positron Emission Particle Tracking (PEPT) to glass, bronze, ilmenite and sand particles showed distinct trajectory maps in three dimension (X,Y and Z) with varying particle speeds in the vertically vibrated particle mixtures. The low density particles were mostly observed to move in the middle while the high density particles patrolled in the outer periphery of the separation cell. These distinct particle motions suggested that convection currents played an important role in controlling segregation. Furthermore, the application of a smoke blanket visualization technique showed the existence of air convection currents on top of the vertically vibrating particle mixtures. The experiments on the scaled up semi-continuous particle separator confirmed what was identified previously in that good particle separation could be achieved through careful control of the frequency and acceleration during vertical vibration. This information lays the foundations for a new breed of low cost, dry separator for fine particulate mixtures. Key Words: Vertical vibration, particle separator, fine particle mixtures, dry separation, PEPT, DEM, smoke visualizations.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Simulations of a multicomponent mixture in the reflux classifier todemonstrate the effect of dispersion coefficient on its internal state

In this study, influence of the dispersion coefficient on the internal state of a multicomponent mixture comprising 35 types of particle species with five different sizes ranging -2.0+0.25 mm and seven different densities, 1400 to 2000 kg/m3, in a reflux classifier under continuous process conditions is presented. Simulations were performed to study the effect of dispersion coefficient on the separation density, D50, separation efficiency, Ep, and solid volume fraction of the multicomponent mixture. The simulation results provided a good agreement with the published experimental results of the reflux classifier, operated at full scale in 2005, for a relatively high value of the dispersion coefficient, 0.0030 m2/s, and a relatively small value of the dispersion, 0.00030 m2/s, in the fluidization and inclined sections of the device, respectively. Moreover, different fixed values of the dispersion coefficient and a published proposed model of the dispersion coefficient were incorporated in the model to examine variations in the system and were compared with the validated simulation results. It was found that the selected values of the dispersion coefficient had not much effect on the $D_{50}$ values. However, the Ep values changed significantly with changes in the dispersion coefficient values. The smaller values of the dispersion coefficient provided lower values of the Ep that did not match well with the validated simulation results. Furthermore, the variations in the total solid volume fraction within the reflux classifier for different values of the dispersion coefficient has been demonstrated

Energy-Efficient and Environmentally Sound Technique of Emulsification and Phase Inversion for Producing Stable Droplets – Application of Membrane Emulsification to Polymerization: A Review

Emulsification plays an important role in the formation of many products such as milk products, pharmaceuticals, lubricants, paints, dyes, and many food items. Their application in industry such as mining, crude oil extraction, pulp and paper, textile, and polymer, is immense. Over the last two decades there has been a growing interest in making emulsions by a new technique known as membrane emulsification. This is because it requires lesser energy as compared to the other conventional turbulence based methods like homogenization and rotor-stator systems, with the added advantage of producing droplets of a given size by just selecting the average pore size of the membrane. It is the distinguished feature of membrane emulsification that the resulting droplet size is controlled primarily by the membrane type and its pore size and not by the generation of turbulent droplet breakup. This article provides a review of the currently available emulsification processes with special focus on polymer emulsification. The main characteristics of emulsification processes including membrane emulsification process and its principles, influence of process parameters, industrial applications as well as an outlook to further improvement of the processes are discussed

IDENTIFICATION OF SITES FOR ESTABLISHING PHOTOVOLTAIC SOLAR FARMS IN PAKISTAN USING SOLAR GEOMETRY

Utility scale Solar farms generally consist of multiple arrays of Photovoltaic (PV) Panels which collect and convert solar energy into electrical energy. Pakistan is facing a serious energy crisis. It is working on solar energy options. Therefore, it is imperative to identify most viable sites that have a high solar radiation. We utilized solar geometry and the Google Earth, a geographical information program to identify optimal sites for Pakistan. These sites should also include basic requirements for a PV plant such as availability of local grid, barren land, roads, water, and good climatic conditions. The Average solar intensity (I) was calculated by using solar geometry on a daily basis, which served as the basis for annual projections. It has been found that the best location for building a solar farm is district&nbsp;QilaSaifullah (I = 9.79 kWh/m2/day) in Baluchistan province. In the Khyber Pakhtunkhwa province, district Nowshera (I= 8.06 kWh/m2/day), in Sindh province, district Sukkur (I = 7.9 kWh/m2/day) and in Punjab, district Bahawalpur (I= 8.17 kWh/m2/day) have been found most suitable. This study shows that Pakistan has a good potential to install solar parks in all the provinces and provides a potential solution to address the energy crisis in Pakistan