993 resultados para Coal combustion


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Rehabilitation of Alcoa's Anglesea open cut brown coal mine to a healthy lake has many environmental challenges. The study of regional acid drainage, limnology of Wenslydale Coal Mine Lake and passive bioremediation of acid mine water has shown that a healthy lake can be created.

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Solar-aided power generation (SAPG) is capable of integrating solar thermal energy into a conventional thermal power plant, at multi-points and multi-levels, to replace parts of steam extractions in the regenerative Rankine cycle. The integration assists the power plant to reduce coal (gas) consumption and pollution emission or to increase power output. The overall efficiencies of the SAPG plants with different solar replacements of extraction steam have been studied in this paper. The results indicate that the solar thermal to electricity conversion efficiencies of the SAPG system are higher than those of a solar-alone power plant with the same temperature level of solar input. The efficiency with solar input at 330 °C can be as high as 45% theoretically in a SAPG plant. Even the low-temperature solar heat at about 85 °C can be used in the SAPG system to heat the lower temperature feedwater, and the solar to electricity efficiency is nearly 10%. However, the low-temperature heat resource is very hard to be used for power generation in other types of solar power plants. Therefore, the SAPG plant is one of the most efficient ways for solar thermal power generation.

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Purpose – This paper aims to propose a conceptual framework to explore the link between strategic human resource management (SHRM) and firm performance of the coal mining companies in Central Queensland (CQ), Australia.

Design/methodology/approach – The paper reviews literature relating to the process and issues of transforming human resource practices and industrial relations of the coal industry in Australia for the past decade. Theoretical development and empirical studies on the SHRM-performance linkage are discussed. Based on the literature review, the paper develops an integrated model for testing the relationship between SHRM and firm performance in the context of CQ's coalmines and proposes a number of research propositions.

Findings – Three perceivable outcomes are likely derived from application of this framework in the field. First, a testing of the linkage between strategic HRM and firm performance in the coal industry, using an integrated approach, would complement the empirical deficiency of treatments on the prior SHRM models. Second, data at firm level could be collected to develop a better understanding of how the adoption of strategic HRM practices in coal companies can affect firm performance. Third, the extent of flexibility practices, use of contractors and associated management practices could be identified.

Originality/value – The coal industry is central to economic development of regional Queensland. The industry contributes substantially to GDP via employment, investment and product export. An exploration of the impact of SHRM on the coal industry will likely result in identifying some best practices that could be potentially adopted in the wider business community to foster regional economic development in Australia and worldwide.

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Variable compression ratio enables an engine to achieve increased efficiency at part loads, where the majority of driving occurs, without sacrificing full load power requirements or increasing the risk of engine knock. Although over 100 patents and patent applications exist none of these systems has been commercialized yet due to issues related to feasibility, cost and frictional loss. A new approach of a self controlling variable compression ratio connecting rod is presented that does not need a friction intensive external activation and that could even be retrofitted. The potential in fuel consumption and exhaust emission reduction as well as increased power and torque output for this concept has been verified in combustion simulations utilizing the latest research results related to the dynamic heat transfer in the combustion chamber from Professor Kleinschmidt from the University of Siegen, Germany. The self controlling variable compression ratio connecting rod allows the con rod to compress at high load conditions thereby increasing cylinder volume to alleviate combustion pressures and temperatures and therefore limit knock onset. The biggest efficiency gains can be achieved at medium load where the reduction of heat loss during the compression of the connecting rod plays a major role additional to the well known efficiency gains of an increased compression ratio. The combustion simulation results shows fuel consumption can be reduced by between 3% and 5% during part load and wide open throttle operation at various engine speeds. Emissions are also reduced significantly; particularly NOx and CO emissions were reduced by up to 35%.The self controlling variable compression ratio connecting rod allows the con rod to compress at high load conditions thereby increasing cylinder volume to alleviate combustion pressures and temperatures and therefore limit knock onset. The biggest efficiency gains can be achieved at medium load where the reduction of heat loss during the compression of the connecting rod plays a major role additional to the well known efficiency gains of an increased compression ratio.The combustion simulation results shows fuel consumption can be reduced by between 3% and 5% during part load and wide open throttle operation at various engine speeds. Emissions are also reduced significantly; particularly NOx and CO emissions were reduced by up to 35%.

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It is well known that the gas–solid system plays a significant role in many industrial processes. It is a complex physical and chemical process, generally consisting of heat transfer, mass transfer, species diffusion, and chemical reactions. In this paper, the reaction of methane with air at a low air factor and the gas flow in a fluidized bed with 0.1 mm solid particles are computationally simulated to enable the study of the effect of the inert particles on the species diffusion and the chemical reactions. The reaction of methane and air is modeled by a two-step reaction mechanism that produces a continuous fluid phase composed of six gases (CH4, CO, O2, CO2, H2O, and N2) and discrete solid particles in the reactor. The simulation results are compared with experiment and show that the finite rate model and the eddy dissipation model can well describe the reactions of gases in high-density gas–solid systems. The distribution of each gas and the particle behaviors are analyzed for incomplete combustion at different concentrations of loaded solid particles. The inert particles change the reactions by enhancing both the chemical kinetics and the species diffusion dynamics.

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Coal handling is a complex process involving different correlated and highly dependent operations such as selecting appropriate product types, planning stockpiles, scheduling stacking and reclaiming activities and managing train loads. Planning these operations manually is time consuming and can result in non-optimized schedules as future impact of decisions may not be appropriately considered. This paper addresses the operational scheduling of the continuous coal handling problem with multiple conflicting objectives. As the problem is NP-hard in nature, an effective heuristic is presented for planning stockpiles and scheduling resources to minimize delays in production and the coal age in the stockyard. A model of stockyard operations within a coal mine is described and the problem is formulated as a Bi- Objective Optimization Problem (BOOP). The algorithm efficacy is demonstrated on different real-life data scenarios. Computational results show that the solution algorithm is effective and the coal throughput is substantially impacted by the conflicting objectives. Together, the model and the proposed heuristic, can act as a decision support system for the stockyard planner to explore the effects of alternative decisions, such as balancing age and volume of stockpiles, and minimizing conflicts due to stacker and reclaimer movements.

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Traditionally, a shareholder’s expectation of receiving a dividend has been limited by the discretion the board of directors has to recommend the appropriate amount of payment as a dividend. As a general rule, shareholders will only be entitled to a dividend after the dividend is declared (normally, at the general meeting), or when the actual date arrives for the dividend to be paid. Because courts were traditionally reluctant to interfere with the internal management of companies, the remedies available to shareholders to compel a company to declare a dividend were very limited. As a result, if the directors have decided to withhold dividend payment, courts will only make an order requiring dividends to be paid under very exceptional circumstances. In this article, the authors discuss the case of Sumiseki Materials Co Ltd v Wambo Coal Pty Ltd [2013] NSWSC 235, which is exceptional for the court’s recognition of a shareholder’s contractual right to a dividend. The article analyses the court’s approach, which found that withholding dividend payments was oppressive and unfairly prejudicial conduct of the company. It also discusses the significance of shareh9olders entrenching their rights in a company’s constitution, irrespective of the fact that a company has a statutory right to alter its constitution by way of a special resolution.