No abstract

One predicted consequence of global warming is the thinning of Arctic sea ice. This raises the question whether the fabled Northwest Passage can be used for year round ship traffic, and whether the distance saved by using the polar route justifies the incremental investment in ice-breaking ships. A conceptual study using computer simulation was conducted to evaluate the Northwest Passage versus the Panama Canal routes between eastern North America and Japan. Recent historical ice conditions were modelled stochastically to calculate ship transit time. The economic performance was then evaluated by estimating the port-to-port shipping cost component of the overall required freight rate, again using stochastic modelling for a variety of cost factors. The most critical economic variable is the incremental capital cost between an ice capable and a standard Panamax ship. Shipping from St John's Newfoundland to Yokohama is economic through the Northwest Passage even with an incremental capital cost of 80%. Extending the route to New York would make the Northwest Passage non-competitive. We report the sensitivity of the port-to-port shipping cost for a number of economic factors, with capital and fuel cost being the most significant. Maritime Economics & Logistics (2007) 9, 324–334. doi:10.1057/palgrave.mel.9100185

The paper proposes the adaptation of the industrial plant’s power network to supply electric vehicle (EV) fast-charging converters (above 300 kW) using renewable energy sources (RESs). A 600 V DC microgrid was used to supply energy from RESs for the needs of variable speed motor drives and charging of EV batteries. It has been shown that it is possible to support the supply of drive voltage frequency converters (VFCs) and charging of EV batteries converters with renewable energy from a 600 V DC microgrid, which improves the power quality indicators in the power system. The possibility of implementing the fast EV batteries charging station to the industrial plant’s power system in such a way that the system energy demand is not increased has also been shown. The EV battery charging station using the drive converter has been presented, as well as the results of simulation and laboratory tests of the proposed solution.

High-resolution spatial numerical models of metallurgical properties constrained by geological controls and more extensively by measured grade and geomechanical properties constitute an important part of geometallurgy. Geostatistical and other numerical techniques are adapted and developed to construct these high-resolution models accounting for all available data. Important issues that must be addressed include unequal sampling of the metallurgical properties versus grade assays, measurements at different scale, and complex nonlinear averaging of many metallurgical parameters. This paper establishes techniques to address each of these issues with the required implementation details and also demonstrates geometallurgical mineral deposit characterization for a copper-molybdenum deposit in South America. High-resolution models of grades and comminution indices are constructed, checked, and are rigorously validated. The workflow demonstrated in this case study is applicable to many other deposit types.

Low-rank coals are widely used as fuel in coal-fired power plants. Continuing the use of these fuels is under huge pressure because of stringent environmental regulations. The air dense medium fluidized bed (ADMFB), which is a dry physical coal beneficiation method, can offer an efficient and economical solution for ash removal. The performance of the ADMFB separator in preparing higher quality coals has been studied by detailed characterization of the ADMFB clean coal products with minimum ash content, maximum organic material recovery, or different feed particle sizes in the present work. The percentage of ash removal for the selected samples with particle size of 1−13.2 mm was between 9 and 22% with respect to the feed sample. An increase of all CHNS components and higher heating value (HHV), regardless of the coal particle size, and a very efficient mercury rejection of between 33.7 and 48.6% were observed for most of the beneficiated samples. Inductively coupled plasma− mass spectrometry (ICP−MS) analysis confirmed the decrease of most of the hazardous elements, such as Pb, Ag, Ba, Cu, Mn, Be, and K, indicating a positive affinity of these elements with the ash-forming minerals of the coal. Some elements, such as As, Se, and Sb, exhibited inconsistent results, which indicates various degrees of organic bonding for these elements. X-ray fluorescence (XRF) analysis of the ashes of the beneficiated coals revealed different decreasing levels of Si, Al, and Mg oxides (main components of clay minerals) and an increase of Na, Ca, and Fe oxides. Lower viscosities, a lower reducing ash fusion temperature (< ∼1250 °C), and consequently, an increased slagging propensity based on a number of simple slagging indices for beneficiated products were obtained. The change in the reactivity of the clean coal products was discussed on the basis of the maximum rate of weight loss (R max ) and the peak temperature (T max ) obtained by differential thermogravimetry (DTG). The fine and middle size beneficiated samples showed various degrees of reactivity improvement. R max for the middle size was found to increase by at least 84.5%, and T max for the same was found to decrease by at least 62 °C.