6,368 research outputs found

    System Dynamics Simulation of Energy Saving and Emission Reduction in Coal Mining Area

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    This paper established a system dynamics model of energy saving and emission reduction in coal mining area, as well as conducted simulation of different development plans, based on the analysis of energy saving and emission reduction factor of coal production links, of the complex structure of energy saving and emission reduction system in coal mining area, and of the dynamic feed-back mechanism inside the system. Result shows that total investment, coal production investment, environmental protection investment and coal energy consumptions per ton play an important part in the energy saving and emission reduction system in coal mining area. By adding total investment and refining the proportion between coal production investment and environmental protection investment, as well as reducing coal energy consumptions per ton, harmonious development of economic and energy saving and emission reduction could be achieved

    Estimation on Economic Cost of China's New De-sulfur Policy During Her Gradual Accession to WTO: The Case of Industrial SO2 Emission

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    To understand the potential impacts of China’s accession to WTO in her new de-sulphur policy (reduction of 10% of SO2 emission in 2005 with respect to that of 2000), we construct a CGE model in which the SO2 emission is linked directly to energy intermediary consumption in production. The positive externality of trade on China’s economy is also included. This model is then calibrated into a 55-sector Chinese SAM of year 1997. Four policy simulations (BaU, Open, Desulfur, Open+Desulfur) are made for 1997 till 2005 and the Divisia index decomposition method is used to analysis the simulation results. The principal results show the environmental impact of trade, though proven to be “negative”, stays rather modest. This is due to the effect of industrial composition transformation that deviates towards labor-intensive sector specialization under the new trade liberalization process. We also find supposed some modest trade externality effect to contribute to pollution reduction and we do not find proof for “pollution haven” hypothesis. Although seemingly to be quite ambitious, the new de-sulphur policy will only bring very slight economic growth lose. The most part of pollution reduction will be realized by the substitution between polluting and less or non-polluting energies. The combination of the trade liberalization and pollution control policies seems to give China more flexibility in adapting her economy to the new de-sulphurs objective. Considering different aspect together, the total economy loss due to new de-sulphur policy will be limited to only –0.18% under the presence of trade liberalization.Externality., Energy substitution, Industrial SO2 pollution, Trade, CGE

    Applications of Advanced Computational Modelling for Principal Underground Mining Hazards Management and Control

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    Underground coal mining is facing increased threats from the hazards of spontaneous combustion and heating of coal, abnormal mine gas emissions, and harmful dust concentrations in underground workings, due to increased production outputs and extraction depth of cover. To control and mitigate these engineering problems, there is a need to gain critical knowledge of spontaneous heating in the longwall (LW) goaf, gas migration patterns onto the LW face, and ventilation dynamics and dust dispersion in complex underground environments. Advanced Computational Fluid Dynamics (CFD) modelling can be used to simulate various scenarios portraying these hazards that may occur in underground LWs and provide much-needed knowledge and fundamental science that can be used to develop robust and effective control and mitigation strategies against these hazards. A comprehensive literature review has been conducted to understand these principal mining hazards (PMH), with a particular emphasis on the applications of CFD modelling in the prevention management and control of those PMH arising during coal extraction process. The insufficiencies and gaps in research on spontaneous combustion in active LW goaf, gas migration onto the LW face, and dust dispersion and transport in the development heading were identified. In addition, several field studies were carried out in underground coal mines in Australia to gain a better understanding of these mining issues and collate essential data for the CFD modelling studies. In recent years, goaf heating and spontaneous combustion incidents have been reported in several Australian underground coal mines during normal production cycles. The onset of these heating incidents was dictated by many operational and environmental parameters. Based on the site-specific conditions of an underground coal mine, where the coal seam gas is of approximately 80% carbon dioxide (CO2) and 20% methane (CH4) with a gas emission rate of 2000 l/s, CFD models were developed and validated with field gas monitoring data collected from the Tube Bundle System. The CFD models incorporated a user defined function (UDF) of gas emission and permeability variations in a three-dimensional (3D) space of computational domain representing the LW panels and goaf areas. Simulation results indicated that better goaf inertisation could be achieved when nitrogen (N2) was injected via cut-throughs (C/T) at about 250 m behind the LW face on the maingate (MG) side and surface boreholes at 100 m and 700 m on the tailgate (TG) side, with a total injection rate greater than 1750 l/s. The oxygen concentration on the MG and TG side dropped below 5% at distances of 120 m and 75 m behind the LW face, with a confined oxidation zone area of 35375 m2, which was approximately one-third of the oxidation zone area without inert gas injection. The impact of geological variations (i.e., coal seam orientations and goaf gas composition) on spontaneous combustion prevention and management was further studied using CFD models. The influence of ventilation design and operational parameters (e.g., tightness of the goaf seals) on spontaneous combustion control was also investigated by additional CFD models based on field data. During LW sealing-off, the ventilation flow dynamics change within the goaf, which considerably increases the risk of spontaneous combustion and gas explosion. To prevent these hazards, CFD models were developed and calibrated with field gas monitoring data to simulate a range of operational scenarios of different ventilation arrangements. The modelling studies indicated that at least six gas sensors should be employed and positioned appropriately to ensure effective goaf atmosphere monitoring for risk management during the LW sealing-off process. Extensive CFD-DPM (Discrete phase model) coupling modelling studies were conducted to investigate dust-related issues in LW gateroad development panels. Based on site-specific conditions, a CFD model incorporating a Continuous Miner (CM), Shuttle Car (SC) and exhausting ventilation tube was established and validated with onsite dust monitoring data. Three scenarios of CM cutting at the middle, floor and roof positions were considered and simulated. In all cases, the simulation results indicated that high levels of dust exposure would occur to left-hand-side (LHS) operators and consequently they should be equipped with high-quality personal protective equipment and stay behind the ventilation duct inlet during coal cutting process, while miners standing at the right-hands-side (RHS) of the CM for roof and/or rib bolting and machine operation should stay immediately behind the bolting rig where dust concentration was relatively low. The studies conducted in this thesis provided new insights into the current goaf inertisation practices to effectively manage and control spontaneous heating in LW goaf by considering geological variations and mining design. Furthermore, the CFD modelling study of gas flow dynamics during the panel sealing-off process provides new knowledge of ventilation and goaf gas dynamics, which is critical to the positioning of gas monitoring sensors to reliably measure goaf atmosphere changes, thus minimizing spontaneous heating and gas explosion risks with much-improved mine safety. The research work also shed light on the dust and ventilation behaviour in gateroad development panels, and provided several recommendations for operators’ locations and dust mitigation strategies to improve the health and safety of miners. The research outcomes from this study contribute to the improvement of current practices and guidance for PMH management and control in underground mines and tunnelling projects

    Policy assessments for the carbon emission flows and sustainability of Bitcoin blockchain operation in China

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    The growing energy consumption and associated carbon emission of Bitcoin mining could potentially undermine global sustainable efforts. By investigating carbon emission flows of Bitcoin blockchain operation in China with a simulation-based Bitcoin blockchain carbon emission model, we find that without any policy interventions, the annual energy consumption of the Bitcoin blockchain in China is expected to peak in 2024 at 296.59 Twh and generate 130.50 million metric tons of carbon emission correspondingly. Internationally, this emission output would exceed the total annualized greenhouse gas emission output of the Czech Republic and Qatar. Domestically, it ranks in the top 10 among 182 cities and 42 industrial sectors in China. In this work, we show that moving away from the current punitive carbon tax policy to a site regulation policy which induces changes in the energy consumption structure of the mining activities is more effective in limiting carbon emission of Bitcoin blockchain operation

    Selected Papers from the 8th Annual Conference of Energy Economics and Management

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    This collection represents successful invited submissions from the papers presented at the 8th Annual Conference of Energy Economics and Management held in Beijing, China, 22–24 September 2017. With over 500 participants, the conference was co-hosted by the Management Science Department of National Natural Science Foundation of China, the Chinese Society of Energy Economics and Management, and Renmin University of China on the subject area of “Energy Transition of China: Opportunities and Challenges”. The major strategies to transform the energy system of China to a sustainable model include energy/economic structure adjustment, resource conservation, and technology innovation. Accordingly, the conference and its associated publications encourage research to address the major issues faced in supporting the energy transition of China. Papers published in this collection cover the broad spectrum of energy economics issues, including building energy efficiency, industrial energy demand, public policies to promote new energy technologies, power system control technology, emission reduction policies in energy-intensive industries, emission measurements of cities, energy price movement, and the impact of new energy vehicle

    GTAP-E: An Energy-Environmental Version of the GTAP Model with Emission Trading

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    Energy is an important commodity in many economic activities. Its usage affects the environment via CO2 emissions and the Greenhouse Effect. Modeling the energy-economy-environment-trade linkages is an important objective in applied economic policy analysis. Previously, however, the modeling of these linkages in GTAP has been incomplete. This is because energy substitution, a key factor in this chain of linkages, is absent from the standard model specification. This technical paper remedies this deficiency by incorporating energy substitution into the standard GTAP model. It begins by first reviewing some of the existing approaches to this problem in contemporary CGE models. It then suggests an approach for GTAP which incorporates some of these desirable features of energy substitution. The approach is implemented as an extended version of the GTAP model called GTAP-E. In addition, GTAP-E incorporates carbon emissions from the combustion of fossil fuels and this revised version of GTAP-E provides for a mechanism to trade these emissions internationally as well as domestically. The policy relevance of GTAP-E in the context of the existing debate about climate change is illustrated by some illustrative simulations of the implementation the European emissions trading scheme in 2005. It is hoped that the proposed model will be used by individuals in the GTAP network who may not be themselves energy modelers, but who require a better representation of the energy-economy-environmental linkages than is currently offered in the standard GTAP model.

    Linkage between knowledge management practices towards library user’s satisfaction at Malaysian University Libraries

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    Academic library services have begun to apply various knowledge management (KM) practices in the provision of library services. KM has been developed to enhance the use of organizational knowledge through practices and organizational learning. KM practices include the creation, capture and/or acquisition of knowledge, its retention and organization, its dissemination and re-use, and general responsiveness to the new knowledge. The focus of this research is the assessment of KM practices, particularly creation, acquisition, capture, sharing, recording and preservation, and their effects on Library User’s Satisfaction (LUS) in Malaysian university libraries. The objective of this research is the development of a model to enhance KM processes (i.e. Creation, acquisition, capturing, sharing, recording, and preserving) and to improve library users’ satisfaction. A quantitative approach in research methodology is employed (e.g. Questionnaire) for the purpose of generating new knowledge and understanding of library concerns. The findings of this research show that the overall KM practice at six Malaysian university libraries is at a high level. The findings from the structural model indicated that two KM processes, namely knowledge creation and acquisition, are not supported in terms of KM practices at Malaysian university libraries. Other KM processes, namely capturing, sharing, recording, and preserving are fully supported towards KM practices in the library. Hence, the major contribution of this research is a model, namely KM Practice-Library User’s Satisfaction (KMP-LUS) highlighting six KM processes based on strong Structural Equation Modeling (SEM) fit indices

    Challenges and Prospects of Steelmaking Towards the Year 2050

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    The world steel industry is strongly based on coal/coke in ironmaking, resulting in huge carbon dioxide emissions corresponding to approximately 7% of the total anthropogenic CO2 emissions. As the world is experiencing a period of imminent threat owing to climate change, the steel industry is also facing a tremendous challenge in next decades. This themed issue makes a survey on the current situation of steel production, energy consumption, and CO2 emissions, as well as cross-sections of the potential methods to decrease CO2 emissions in current processes via improved energy and materials efficiency, increasing recycling, utilizing alternative energy sources, and adopting CO2 capture and storage. The current state, problems and plans in the two biggest steel producing countries, China and India are introduced. Generally contemplating, incremental improvements in current processes play a key role in rapid mitigation of specific emissions, but finally they are insufficient when striving for carbon neutral production in the long run. Then hydrogen and electrification are the apparent solutions also to iron and steel production. The book gives a holistic overview of the current situation and challenges, and an inclusive compilation of the potential technologies and solutions for the global CO2 emissions problem

    Global Energy Strategies to Control Future Carbon Dioxide Emissions

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    The objective of the collaborative IIASA-CRIEPI study was to develop an analytical framework and formulate scenarios for evaluating the effectiveness of policy options in global/regional energy systems directed at delaying or mitigating the global-warming effect over the first half of the 21st century. The study is therefore aimed at the development of analytical tools for evaluating long-term energy/climate countermeasure options, taking into account the influence on energy demand and supply of changes in social needs, economic and population growth, governmental policies, and technological progress. The approach is based on scenario simulations to describe those techno-economic and socio-cultural changes which determine future energy-use patterns and their environmental impacts. For this purpose, two scenarios have been formulated: one with changes in society, economic systems, and the energy sector that follow the dynamics-as-usual pattern, and the other with enhanced energy efficiency improvements and conservation efforts. For each scenario three different cases have been analyzed reflecting the possible situations on the energy supply side. Addressing policy makers and specialists in energy demand and supply, the authors evaluate the consequences of various policy options and explore more efficient and effective measures for reducing environmental impacts, for example, through regional interactions such as technology transfer and technological progress. This report describes the relationship between the directions of policy orientations and the global energy situations in the future. The issues that require further investigation include the process of international cooperation on implementing the measures proposed, the evaluation of the costs associated with the construction of future energy systems as well as the introduction of advanced technologies, and formulation of a global strategy to control not only carbon dioxide as examined in this study but also all the greenhouse gases
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