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Yip K.,Curtin University Australia | Ng E.,Curtin University Australia | Ng E.,Worley Parsons Services Pty Ltd | Li C.-Z.,Curtin University Australia | And 2 more authors.
Proceedings of the Combustion Institute | Year: 2011

This paper provides mechanistic insights into the low-temperature oxidation of a range of carbon materials (graphite, a sub-bituminous coal char, and a brown coal char). Kinetic analysis was carried out on oxidation of the chars, prepared from fast-heating pyrolysis, under chemical-reaction-controlled regime. FT-Raman spectroscopic analysis was adopted to provide direct structural information on the carbon structure of reacting carbon materials throughout oxidation. The results demonstrate the significance of selective oxidation under the conditions, and parallel to this, the kinetic compensation effect of carbon oxidation reaction throughout conversion for all samples. Supported by the results from FT-Raman spectroscopy, the kinetic compensation effect seems to be a result of the selective oxidation of these carbon materials with heterogeneous carbon structures. Oxidation of all samples, with or without catalysts, appears to be similar in terms of the 'nature' of carbon structural condensation during low-temperature oxidation, suggesting a similar increase in apparent active sites population with respect to increase of apparent energy barrier. Under the current experimental conditions, a general kinetic compensation effect correlation has been deduced for various materials, requiring only the initial char kinetic parameters. The inherent inorganic species in chars also seem to alter the 'degree/extent' of carbon structural condensation as results of selective oxidation. In this case, the use of the compensation effect correlation will require more information on the catalysis during oxidation, apart from the initial char kinetic parameters. © 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Pokrajcic Z.,WorleyParsons Services Pty Ltd
TMS Annual Meeting | Year: 2010

Crushing and grinding, or comminution, circuits are the most energy intensive process of a mineral processing plant. Comminution involves the physical size reduction of an orebody to a particle size sufficient for recovery of the mineral values. However, the comminution process remains inherently inefficient. The inefficiency is a result of the operating nature of comminution devices such as grinding mills, where transfer of energy between grinding media and particles in unconstrained and completely random. New comminution circuit design strategies are presented in this paper. The aim of the new strategies is to improve the overall efficiency of the comminution process and reduce the total energy consumption of a comminution circuit. The energy efficient strategies include the: • rejection of coarse size liberated gangue from the comminution circuit and further downstream size reduction • use of more efficient grinding and crushing equipment • the selection of coarser particle product sizes to alleviate the increased energy intensity required to achieve finer product sizes Singularly and when combined, these energy efficient strategies can significantly decrease the overall energy consumption of a comminution circuit. This paper also explores the financial impact of certain energy efficient strategies using an analysis tool called EcoNomics™. It shows that substantial financial gains can be made by including more efficient technologies and methods in comminution circuit design.

Almasi A.,Worley Parsons Services Pty Ltd.
Chemical Engineering | Year: 2012

A guidance to improve lubricant selection, whether mineral oils and synthetic oils, process operation and asset reliability is discussed. Mineral oils are more frequently used in chemical process industries (CPI) applications. Synthetic oils offer superior performance in terms of higher oxidation stability, improved corrosion resistance, and the ability to withstand both higher and lower temperatures. When selecting a lubricant for reciprocating or screw compressors, low solubility in compressed gas should be a key selection criteria. For reciprocating or screw compressors, the lubrication oils that meet all of these criteria are mainly synthetic lubricants formulated with PAG base stock. PAG lubricants show less than 20% of the water solubility of typical mineral oils. Synthetic lubricants with ISO VG 100 to 220 ratings are extensively used for reciprocating compressor cylinder packing for process services. Turbine lubricants must have excellent thermal and oxidation resistance at bearing oil temperatures.

Almasi A.,WorleyParsons Services Pty Ltd.
World Pumps | Year: 2012

The sudden failure of a pump component can have serious and costly consequences. Amin Almasi considers the failure modes in a pump's rotating assembly, including resonance issues, fatigue failures, vibration, the chain of events and secondary damage to critical auxiliaries. The discussion is illustrated with case studies. © 2012 Elsevier Ltd.

Almasi A.,Worley Parsons Services Pty Ltd
Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering | Year: 2012

A new study for laminated composite rotating disk fabricated from symmetric sequential quasi-isotropic layers to predict three-dimensional (3D) stress and deformation is addressed. It is used to evaluate the mechanical stress and integrity of fibre reinforced multi-layer laminates used for ultra high-speed impellers of modern process centrifugal compressors. Composite laminates are relatively weak in out-of-plane loading, inter-laminar stress, stress concentration near the edge, and stress singularities. 3D stresses and deformations shall be investigated for laminated composite rotating disk applications. © Authors 2011.

Almasi A.,WorleyParsons Services Pty Ltd
Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering | Year: 2012

The technical and cost advantages of oil-flooded screw compressors have made them the compressor of choice for coal seam gas field compression. The optimum arrangement for this compressor is presented. Lubricant oil provides rotor separating, internal cooling, noise damping, corrosion protection, and considerably higher compression ratio capability. The machine is simple, reliable, efficient, and compact. Critical areas for performance and reliability, including component design and manufacturing, journal and thrust bearing, seals, pulsation, noise, and auxiliary systems are outlined. The best methods of capacity control and condition monitoring are also described. A case study is presented. © Authors 2011.

Almasi A.,WorleyParsons Services Pty Ltd
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy | Year: 2012

A micro-turbine can offer a high availability, a compact design, a reliable operation, an easy maintenance, great fuel flexibility, low dynamic forces and fewer moving parts (usually only one moving assembly). The old-fashion emergency diesel engine generators and battery systems have been used for decades in critical emergency units such as nuclear emergency cooling systems. They seem unreliable and unsuitable for modern facilities. The modern micro-turbine technology is proposed as a reliable, lightweight and compact solution for emergency power supply applications. New application of the micro-turbines for the nuclear facility emergency cooling system is explained. © IMechE 2012.

Worleyparsons Services Pty Ltd | Date: 2014-04-11

A tracking buoy (10), comprising: a body portion (12); and a GPS tracking unit (14); wherein the GPS tracking unit (14) is removably contained on or within the body portion (12), and the mass of the tracking buoy (10) being such that less than about 100 mm of the tracking buoy (10) projects above the waterline during operation.

Almasi A.,WorleyParsons Services Pty Ltd
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy | Year: 2013

The piping designers always want higher allowable machinery nozzle loads to simplify piping designs, while the rotating machine manufacturers want smaller allowable nozzle loads to assure good alignment, higher reliability and fewer operation complaints. From the power plant operator's point of view, where long-term reliability is a very important factor, the vote should go to the manufacturer. Optimum power piping design, support arrangement and layout configuration for rotating machines of a power plant (turbines, pumps, others) are addressed. Modern practical notes, new guidelines, recent lessons learned and latest achievements on power piping, power machinery nozzle load optimization, stress analysis and piping flexibility review are discussed. © IMechE 2013.

Almasi A.,WorleyParsons Services Pty Ltd
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy | Year: 2013

The purpose of this article is to provide new practical guidelines on rotordynamics and stability analysis of power generation trains. Latest methods, modern recommendations, recent lesson learned and new practical notes on power generation machinery rotordynamics are presented. Critical areas relative to safety and reliability of power generation machine design and component selection including the bearing dynamic effects, the rotordynamics study/modelling methods, the third party analysis, the gear unit dynamic and potential instability sources are discussed. The main concern is the correct design and dynamic study of a power generation train before the equipment fabrication and the component sub-supply started and for some issues even before the train order. Case studies are also presented. © IMechE 2013.

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