A Study on Thermo-catalytic Degradation for Production of Clean Transport Fuel and Reducing Plastic Wastes

AbstractBoth the landfilling and incineration processes of plastic waste management system are identified as sources of pollutant gas emitters. Reprocessing is also uneconomical in comparison to the virgin plastic products in terms of commercial values due to polymeric contamination. This article studies the thermo-catalytic conversion processes waste plastics. The reaction conditions and the quantification of types of catalysts used for the conversion processes influenced the quality of the resultant hydrocarbons. Obtaining higher yield of conversion and transport grade fuel require more investigation to adapt this technical process as one of the effective alternative resources for fuel production. Thermo-catalytic process resolves the problem of halogen contents in the PVC type plastics by converting them into residues with the use of NaHCO3 and AgNO3 which capture chlorine type products from the gaseous hydrocarbons. Addition of catalysts in the convenient reactor reduces the requirement of higher temperature operations like thermal cracking processes and produces more liquefied products. It has been observed that, the aromatic plastic contents should be observed during the conversion process to obtain fuels based on allowable aromatic contents according to the fuel standards and emission regulations implemented in respective regions. The temperature of the process need to be controlled as per the boiling points of the mixture contents to avoid formation of vapor in the reactor which could causes sticky adherence to the reactor walls. A continuous liquid fractionating distillation process can reduce the formation of light gases in the yield. It was also found that the mixture of LDPE, HDPE, PP and PS yield 87.19% fuel with 20 wt% ZnO catalyst at 200 – 400°C in a steel reactor. These fuels can be used directly in the automotive engines or can be retreated in the refineries to divide into gasoline and diesel fuels as per carbon chains. Since the plastic feedstocks do not contain any sulfur components the produced fuel can be treated as clean enough. Thus the fuels produced from this process can be considered as one of the potential alternative resources of fuel production resulting into an effective reduction of plastic wastes in a country

Biofuel: An Australian Perspective in Abating the Fossil Fuel Vulnerability

AbstractThe fossil fuels are now considered as one of the most environmentally unsustainable energy resources though they are the major energy source for transport sectors and other industries. Increased demand of fuel consumption can lead to the threat of energy supply instability and the consequences of energy uses and emission on both environment and economy are significant concerns of most of the countries. This article reviews the vulnerability of Australian fuel supply chain and a brief description on how biofuels can turn into significant alternative resources of fossil fuel. It has been observed that the prospective applications of biofuel can assist in abating both the greenhouse gas (GHG) emissions and fossil fuel vulnerabilities. Currently, Australia imports about 37% of the total crude oil demand managing a diverse supply chain system. The local refining capacities are not utilized properly. No more technically advanced projects are under consideration to achieve self-sufficiency to make the best use of domestic crudes in order to reduce the fuel imports. Though Australia possesses abundant facility of producing inedible biofuel feedstocks, high costs for feedstock processing has caused shut down of 68% of the existing biofuel refineries. But, biofuels can reduce over 60% of the GHG emissions caused by the same amount of fossil fuels. Though the Government has granted an excise of flat tax on biofuels until 2021 to promote the commercial growth in this sector, the lack of infrastructure investment from the Government has been slowed the progress of this industry since its inception. Establishment of regional biofuels refineries can reduce both the distribution transport cost and import load of the fossil fuels. Being alternative resources, biofuel production can effectively make the best use of deserted or unused lands, creating employment opportunities and reducing both fossil fuel market instability and environment pollutions

Exergy Analysis and Efficiency Improvement of a Coal Fired Thermal Power Plant in Queensland

Energy analysis is an important tool to improve energy efficiency of a thermodynamic system. The conventional method of energy analysis is based on the first law of thermodynamics, which focuses on conservation of energy. The limitation of this analysis is that it does not take into account properties of the system environment, or degradation of the energy quality through dissipative processes. Exergy analysis is very effective in this regard, as it deals with the usable energy with reference to environment. It is based on the second law of thermodynamics. The main purpose of exergy analysis is to identify where and how much exergy is destroyed. This destruction of exergy in a process is proportional to the entropy generation in it, which accounts for the inefficiencies due to irreversibility. This research conducts exergy analysis in one unit of a coal-fired power plant in Central Queensland, Australia. The exergy analysis identifies where and how much exergy is destroyed in the system and its components. Based on the analysis, it assesses different options to improve the efficiency of the system. It shows that only a small amount of useful energy can be recovered through a heat recovery system. Substantial improvement to the thermodynamic cycle is possible, but it requires considerable alteration of the power generation system

An Experimental Study of Bubble Rise Characteristics in non – Newtonian (Power-Law) Fluids

Air bubbles are used in chemical, biochemical, environmental, food process such as sugar industries for improving the heat and mass transfer. In particular, the bubble rise characteristics in massecuite - a fluid made from sugar crystals and sugar syrup have a great influence on vacuum pan operation which is an important process for the production of raw sugar in sugar industries. An experimental study of the bubble rise characteristics in xanthan gum solutions, a non-Newtonian (Power-Law) massecuite equivalent fluid are presented in this paper. The main characteristics, i.e. the bubble velocity, the bubble trajectory, and the drag relationship were investigated as a function of volume of air bubbles. The bubble rise velocity and trajectory were measured using a combination of non-intrusive (high speed photographic) method and digital image processing. The parameters that significantly affect the rise of air bubble are identified. The effect of different bubble volumes and liquid heights on the bubble rise velocity and bubble trajectory are analysed and discussed. A relationship between the Reynolds number and the drag coefficient is presented and discussed

A comparative study of bubble rise phenomena in water and low concentration polymer solutions

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.Bubbles are used in polymer, metallurgy, biotechnology and especially in process industries for improving the heat and mass transfer from a dispersed gaseous phase to viscous liquid phase. A comparative study of the bubble rise characteristics in water and a few selected low concentration polymer solutions is presented in this paper. The characteristics, namely, the bubble velocity, the bubble trajectory, the bubble volume and the drag relationship are investigated. The experiments were conducted in 125 mm cylindrical column at liquid heights of 1 m, 1.2 m, 1.4 m and 1.6 m by introducing different bubble volumes (from 0.1 mL to 5.0 mL ) corresponding to each height. The bubble rise velocity and trajectory were measured using a combination of non-intrusive (high speed photographic) method and digital image processing. The parameters that significantly affect the rise of air bubble are identified. The effect of different bubble volumes and liquid heights on the bubble rise velocity and bubble trajectory are analysed and discussed. The correlation between the Reynolds number and the drag coefficient is developed and presented. The results of this study are compared with the results of other analytical and experimental studies available in the literature.cs201

Simulation of building thermal performance in an institutional building in subtropical climate

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.Simulation of building thermal performance is important in predicting comfort of the occupants in buildings. An analysis and prediction of thermal comfort using DesignBuilder based on EnergyPlus, state of the art building performance simulation software, is presented in this study for an air conditioned multistoried building in Rockhampton city of Central Queensland, Australia. Rockhampton is located in a hot humid region; therefore, indoor thermal comfort is strongly affected by the outdoor climate. The actual thermal condition of the Information Technology Division (ITD) Building at Central Queensland University during winter and summer seasons is evaluated and the possibilities of energy conservation without compromising thermal comfort of the occupants are explored. The Fanger comfort model, Pierce two-node model and KSU two-node model were used to predict thermal performance of the building. A sophisticated building analysis tool was integrated with thermal comfort models which allow for the determination of appropriate cooling technologies for the occupants to be thermally comfortable with sufficient energy savings. This study will also compare predicted mean vote (PMV) and thermal sensation vote (TSV) on a seven point thermal sensation scale calculated using the effective temperature, relative humidity, discomfort hours for alternative cooling and ventilation techniques.cs201

Thermal performance modelling of data centre– a case study

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.This paper presents a computational study of thermal modelling of the data centre located at CQUniversity, Rockhampton Campus, Australia. The data centre was modeled and analyzed using computational fluid dynamics (CFD) model to study the effectiveness of cooling within the racks and aisles of the centre. CoolSim- software was used for designing a graphical user interface (GUI) that allows data centre components to be positioned, sized and characterized in a plan view. Modelling of airflow and temperature distribution in the data centre was performed using the CFD code Fluent. The CFD model based on thermal mass and energy balance principles was calibrated with the actual measurements of energy consumption, pressure and temperature from a standard rack filled with a set of rack mounted processor and storage units. The simulation results identified the potential high temperature zone within the computer rack in the data centre, and provide a detailed 3D analysis of how cold air is moving through the data centre. The results also provide the performance analysis of computer room air conditionings (CRACs), detailed rack-by-rack inlet and exit temperatures and 3D thermal mapping of the data centre and racks highlighting trouble areas. The model developed was capable of evaluating the airflow rates and thermal loads for optimizing and designing a new or existing data centre.dc201

Analysis and comparison of engine performance and exhaust emissions of internal combustion engine for three different fuel efficiency devices

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.The engine performance and exhaust emissions characteristics of an internal combustion engine using three different fuel efficiency devices, namely Hiclone, Supermax and FFC are analyzed compared and discussed in this paper in order to identify the best fuel efficiency device among three. The testing was done in a 2.4L 4-cylinder Toyota Camry 2AZ- FE engine. The procedure recommended by Environmental Protection Agency (EPA) Aftermarket Retrofit Device Evaluation Program was used for engine testing. All the results obtained were when the devices were fitted and compared with results when no device was fitted with the engine. This study found that there is no significant increase/decrease of brake power, brake torque, fuel consumption and exhaust emissions for these fuel efficiency devices. Further study is recommended in order to come to an acceptable conclusion.dc201

Fluid flow chractericitics on scale deposition in a concentric reducer using CFD approach

Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.Fluid flow phenomenon in a concentric reducer is modelled by computational Fluid Dynamics (CFD) approach to examine the role of fluid velocity in scale formation. Scale formation in alumina refineries is a common phenomenon and it occurs where supersaturated solutions are in contact with solid surfaces. It often leads to serious on-going technical problems and is a major cause of production loss due to equipment downtime required for descaling and cleaning operations. The scale formation mechanism in Bayer process equipment is complex and is not yet fully understood. Numerous researchers indicate that scale growth is strongly affected by fluid velocity while also influenced by a number of other factors such as the quality of bauxite ore, rheological properties of fluid, turbulence and inertia of suspended particles and adhesive property of particles. A numerical study using the Finite Volume Method to analyse the fluid dynamics behaviour of water as it flows through a concentric reducer commonly used in the Bayer plant is presented. The simulation results show a significant variation of the stream-wise (u′ ) and crossstream (u′ ) components of the fluctuating velocity as flow passes through the concentric reducer.am201