Volume 3 Issue 2

Authors: Gobi Kannan Supramaniam; Aizam Talib; P. Eng,C.Eng.

Abstract: Tenaga Nasional Berhad (TNB) has experienced over 40 cases of high voltage Current Transformers (CT) failures since 2001 to 2011. Post failure analysis indicated that these failures are suspected highly due to deterioration and contamination of the main insulation system. To reduce premature failures and improve the reliability of the asset, TNB has embarked on a trial study on the use of dielectric response technique known as Frequency Dielectric Spectroscopy (FDS) to assess the insulation condition of in-service high voltage CTs. Field measurements were conducted on selected 137 units CT of voltage class 132 kV and 275 kV in TNB Transmission system. Analysis guideline and flow-chart was developed based on typical value of measured parameters for accurate assessment. To reduce premature failures on CTs, strategic decisions were made based on measured CT conditions and its assessment results.

Keywords: Current Transformer; Assessment; Dielectric Response Technique; Analysis Guideline


Authors: James Ogbona; Hideno Tanaka; Hideki Aoyagi; Akihiro Hideno

Abstract: Maitake mushroom, which is the fruiting body of Grifola frondosa (white-rot fungus), is extensively cultivated in Japan using mainly hardwood-sawdust (HS) as the medium. After cultivation, a large amount of spent-sawdust matrices (SSM) is discharged, resulting in high disposal cost. It is therefore necessary to develop effective methods for the bioconversion of SSM into fuels and chemicals. The moisture content of SSM is approximately 70%, and hence it should be dried to prevent decay during storage and reduce the transportation cost. In the present study, the thermal properties of SSM and their effects on the enzymatic hydrolysis of SSM were investigated by carrying out a differential thermogravimetric analysis (TG/DTA). The thermal analyses showed that the thermal decomposition of SSM occurs more easily than HS. A high heating rate (100°C min-1) and high temperature (500°C) did not improve the enzymatic hydrolysis of SSM. The optimal drying temperature for grinding and saccharification ranged from 25 to 200°C, while the optimal rate of temperature increase was 50°C min-1. Under these conditions, the sample temperature of was approximately 121°C. The results of this investigation support our previous conclusion that an autoclave treatment of SSM at 121°C is effective in improving the enzymatic hydrolysis of SSM.

Keywords: Thermal Properties; Thermal Analysis; Spent-Sawdust Matrix; Enzymatic Hydrolysis; Grifola Frondosa


Authors: Mohammad Rashid; Moinuddin Sarker; Mohammed Molla; Muhammad Rahman

Abstract: Plastics use is increasing day by day everywhere. After use all plastics become waste, it creates hazardous environmental problem. Waste plastics are non-bio-degradable and remain in landfill for a long period of time. These waste plastics also end up in the water body which damages the earth’s ecosystems. Waste plastics such as polypropylene (PP) and Polyvinyl Chloride (PVC) are some of the few that are included. Nowadays worldwide researchers are working to find suitable environment friendly sustainable alternate source of liquid fuel. New establish technology is economically viable, technically sound and environment friendly to convert almost all types of waste plastic into eco-friendly liquid fuel. This developed process of conversion of waste plastics into fuel is completely zero pollution system i.e. in the new developed process, there will be no solid, liquid or gaseous emission pollution. The produced fuel from waste plastics can be used for all types of combustion engine, and can be used for the production of electricity using generator and power plant. Implementations of this new developed process throughout the USA can solve 30 million ton of solid waste plastics dumping problem and also rest of the world. The produced fuel from waste plastics will also reduce a certain percentage of the foreign oil dependence.

Keywords: Polypropylene; PVC; Hydrocarbon; Fuel; Halogen; GC/MS; FT-IR


Authors: Johan Sandberg; Chuan Wang; Mikael Larsson

Abstract: With oxygen enrichment in hot stoves (HS) the high calorific coke oven gas can be saved due to the possibility of using lower calorific gases which enables replacement of other imported fuels such as oil or LPG. The application of oxygen enrichment in hot stoves or increased O2 content in the blast to the blast furnace (BF), will also potentially lead to lower coke rate. The demand for coke oven gas depends on internal operation logistics and it also has outdoor temperature dependence through a heat and power plant producing district heat to the community. An analysis of the influence of increased oxygen enrichment in HS-BF on the entire energy system has been carried out by using an optimization model. A method of achieving a high time resolution in MILP optimisation is applied in the analysis. Different strategies have been suggested for minimum energy consumption at the studied steel plant and the nearby combined heat and power (CHP) plant. Central to the performance in system optimisation is the ability to analyse and properly describe the system variations.

Keywords: Oxygen Enrichment; Integrated Steel Plant; Optimization; MILP; Solution Space


Authors: C?p??in? Octavian

Abstract: The aging energy infrastructure, politically controlled fossil resources, the rise of renewable technologies, the geographical distribution feature of renewable energy, climate change exigencies, the increase in domestic electricity consumption have forced the power industry to examine the status and health of the electrical systems. The advancements in real-time processing and computing power made searching for new approach regarding energy systems possible. Solutions are on their way: Smart grid, as a joined space of energy and information, Enernet and Bob Metcalfe’s proposal for an analogy with internet. In our turn, we proposed another view to the energy systems and, at the same time, a holistic vision and an analogy with the autonomous functioning of the biological cells. In our view, the energy systems must be thought of firstly as part of the nature; secondly the system must be conceived as a whole that includes consumers, generators, storage facilities, metering infrastructures, grids and rules; thirdly, to get safety and efficiency it must be modular/cellular and able to do its best as well as part of an ensemble as well as stand alone. To achieve this final require we have made an analogy with the biological cell.

Keywords: Energy Systems; Intelligent Systems; Cell Structure; DNA


Authors: Samuel Chapman; Edward Owens

Abstract: The growth in both onshore and offshore wind power has been rapid over the past few decades and has led to a need for comparable, consistent and reliable life cycle carbon assessment of wind power in order to provide decision-makers with robust information. The current published estimates for wind power range from 2 to 81 gCO2e/kWh. This study reduces this range through a meta-analysis of 82 estimates gathered from 17 independent studies. Through harmonisation of lifetime, capacity factor and recycling, the published range of life cycle carbon emissions estimates is reduced by 56% to between 2.9 & 37.3 gCO2e/kWh. Average values for onshore and offshore wind power are estimated as 16 & 18.2 gCO2e/kWh respectively after harmonisation and onshore and offshore wind power technologies exhibit similar characteristics in relation to their life cycle carbon emissions. Key differences with previous studies are that this study benefits from inclusion of data from a recently published comprehensive offshore wind farm assessment, and harmonisation is conducted for recycling procedures which results in an increase in the lower band of the range of life cycle carbon emissions estimates.

Keywords: Life Cycle Assessment; Wind Power; Harmonisation; Meta-Analysis


Authors: Gang LONG; Yan PENG; Mingzhe NING; Dejian LI

Abstract: In this study, a new strategy to assess the seismic energy dissipation safety of reinforced concrete bridge pier was proposed. Based on dynamic energy equation of multi-degree structures and inverse deduction of Park-Ang damage model under given displacement and damage controlling conditions, a real highway circular bridge pier was analyzed to show the feasibility of present theory and method by use of popular finite element software. The results show that the real ability of energy dissipation of the reinforced concrete circular bridge pier can be calculated under given displacement and damage controlling conditions and then the safety factor can be obtained subsequently in varied earthquake waves corresponding to different seismic classes and damage index where the complex non-linear calculation process related to the restoring force model of the structure becomes unnecessary. The strategy involved in this paper is very simple and easy to be realized which can make full use of the advantage of finite element software and may provide effective means for the seismic assessment of existing or proposed reinforced concrete bridge piers.

Keywords: Dynamic Time Course Analysis; Seismic Energy Equation; Seismic Energy Dissipation Safety Assessment; Reinforced Concrete Bridge Pier; Park-Ang Damage Model