Analysis and optimization of material flow inside the system of rotary coolers and intake pipeline via discrete element method modelling

There is hardly any industry that does not use transport, storage, and processing of particulate solids in its production process. In the past, all device designs were based on empirical relationships or the designer's experience. In the field of particulate solids, however, the discrete element method (DEM) has been increasingly used in recent years. This study shows how this simulation tool can be used in practice. More specifically, in dealing with operating problems with a rotary cooler which ensures the transport and cooling of the hot fly ash generated by combustion in fluidized bed boilers. For the given operating conditions, an analysis of the current cooling design was carried out, consisting of a non-standard intake pipeline, which divides and supplies the material to two rotary coolers. The study revealed shortcomings in both the pipeline design and the cooler design. The material was unevenly dispensed between the two coolers, which combined with the limited transport capacity of the coolers, led to overflowing and congestion of the whole system. Therefore, after visualization of the material flow and export of the necessary data using DEM design measures to mitigate these unwanted phenomena were carried out.Web of Science117art. no. 184

The safety case and the lessons learned for the reliability and maintainability case

This paper examine the safety case and the lessons learned for the reliability and maintainability case

Economic efficiencies of the energy flows from the primary resource suppliers to the electric load centers

The economic efficiency of the electric energy system depends not only on the performance of the electric generation and transmission subsystems, but also on the ability to produce and transport the various forms of primary energy, particularly coal and natural gas. However, electric power systems have traditionally been developed and operated without a conscious awareness of the energy system-wide implications, namely the consideration of the integrated dynamics with the fuel markets and infrastructures. This has been partly due to the difficulty of formulating models capable of analyzing the large-scale, complex, time-dependent, and highly interconnected behavior of the integrated energy system. In this dissertation, a novel approach for studying the movements of coal, natural gas, and electricity in an integrated fashion is presented. Conceptually, the model developed is a simplified representation of the national infrastructures, structured as a generalized, multiperiod network composed of nodes and arcs. Under this formulation, fuel supply and electricity demand nodes are connected via a transportation network and the model is solved for the most efficient allocation of quantities and corresponding prices for the mutual benefits of all. The synergistic action of economic, physical, and environmental constraints produces the optimal pattern of energy flows. Key data elements are derived from various publicly available sources, including publications from the Energy Information Administration, survey forms administered by the Federal Energy Regulatory Commission, and databases maintained by the Environmental Protection Agency. The results of different test cases are analyzed to demonstrate that the decentralized level of decision-making combined with imperfect competition may be preventing the realization of potential cost savings. An overall optimization at the national level shows that there are opportunities to better utilize low cost generators, curtailing usage of higher cost units and increasing electric power trade, which would ultimately allow customers to benefit from lower electricity prices. In summary, the model developed is a simulation tool that helps build a better understanding of the complex dynamics and interdependencies of the coal, natural gas, and electricity networks. It enables public and private decision makers to carry out comprehensive analyses of a wide range of issues related to the energy sector, such as strategic planning, economic impact assessment, and the effects of different regulatory regimes

A roadmap for China to peak carbon dioxide emissions and achieve a 20% share of non-fossil fuels in primary energy by 2030

As part of its Paris Agreement commitment, China pledged to peak carbon dioxide (CO2) emissions around 2030, striving to peak earlier, and to increase the non-fossil share of primary energy to 20% by 2030. Yet by the end of 2017, China emitted 28% of the world's energy-related CO2 emissions, 76% of which were from coal use. How China can reinvent its energy economy cost-effectively while still achieving its commitments was the focus of a three-year joint research project completed in September 2016. Overall, this analysis found that if China follows a pathway in which it aggressively adopts all cost-effective energy efficiency and CO2 emission reduction technologies while also aggressively moving away from fossil fuels to renewable and other non-fossil resources, it is possible to not only meet its Paris Agreement Nationally Determined Contribution (NDC) commitments, but also to reduce its 2050 CO2 emissions to a level that is 42% below the country's 2010 CO2 emissions. While numerous barriers exist that will need to be addressed through effective policies and programs in order to realize these potential energy use and emissions reductions, there are also significant local environmental (e.g., air quality), national and global environmental (e.g., mitigation of climate change), human health, and other unquantified benefits that will be realized if this pathway is pursued in China

Critical Infrastructure Rebuild Prioritization Using Simulation Optimization

This thesis examines the importance of a critical infrastructure rebuild strategy following a terrorist attack or natural disaster such as Hurricane Katrina. Critical infrastructures are very complex and dependent systems in which their re-establishment is an essential part of the rebuilding process. A rebuild simulation model consisting of three layers (physical, information, and spatial) captures the dependency between the six critical infrastructures modeled. We employ a simulation optimization approach to evaluate rebuild prioritization combinations with a goal of minimizing the time needed to achieve an acceptable rebuild level. We use a simulated annealing heuristic as an optimization technique that works in concert with the rebuild simulation model. We test our approach with three disaster scenarios and find that the initial rebuild strategy greatly impacts the time to recover. With respect to the scenarios tested, we recommend a rebuild strategy and areas for further investigation that may be of use to disaster and emergency management organizations

A Review of Energy Models. No. 3 (Special Issue on Soviet Models)

The experience of the USSR in the field of energy systems development modeling reveals certain patterns and principles that influence the structure and use of energy models, principally: -- The need to use mainly optimization models since, for planning purposes, optimal solutions must be found; -- The need to coordinate individual models in order to obtain the country's objectives; -- The existing organizational structure of planning which must be taken into account; -- The dependence of models on time aspects of planning (annual, 5-year, 15-year); -- The elaboration of corresponding methods for providing necessary input data. This has required the development of a special concept for optimizing energy systems development with the use of mathematical models. It is based on consideration of the energy industries of the country as complex with a hierarchical structure of energy systems of various territorial and branch levels. At the same time, the differentiation of aims at different times during the planning period have been taken into account. This concept is given here in its existing state (it is continuously developed and perfected) for better understanding of the energy models described. In particular, we show the role of the system of models for optimization of the energy supply system as a whole, and that of more detailed branch models (oil, gas, coal, electricity production systems). For optimal energy strategy evaluation, the most important models are those used on the highest levels of the energy systems hierarchy, i.e. the general (aggregate) energy systems of the country and of economic regions, and branch energy systems. Only these models are described here; models used on lower levels for solving some technical problems are far more diverse and numerous, and it is impossible to consider them all in a single review

Techno-Economic Assessment of a Biomass-Based Cogeneration Plant with CO2 Capture and Storage

Reduction of CO2 emissions from energy systems could be achieved through: CO2 capture and storage, energy savings, fuel switching among fossil fuels, increased use of renewable energy sources, and nuclear power. In addition, atmospheric CO2 reduction could also be achieved through increasing the carbon stock in soils and standing biomass. The CO2 capture and storage option for mitigating CO2 emissions from biomass-based cogeneration plants, considering critical aspects such future development of technologies, economies of scale. carbon price, site-specific analysis, and future energy systems has received little attention in scientific studies. With the overall objective of improved understanding of the potential scope for its large-scale implementation, a techno-economic assessment of biomass-based cogeneration plants with CO2 capture and storage was carried out. Most of the above-mentioned critical aspects have been considered for the techno-economic assessment of cogeneration plants with CO2 capture and storage technology. The results show the optimal scale of the conversion systems with respect to cost of electricity (COE). The optimal size for steam turbine-based cogeneration (CHP-ST) technologies without CO2 capture lies in the range 98-106 MWe (COE is 5.7 USD/MWh) when fueled by forest/logging residues, but the optimal size increases to 200-227 MWe for integrated gasification combined cycle based cogeneration (CHP-IGCC) (COE is 16.73 USD/MWh). The optimal size increases considerably to 249-288 MWe (COE 15.70 USD/MWh) for Salix fueled CHP-ST technology without CO2 capture and 441-504 MWe (COE 27.52 USD/MWh) for CHP-IGCC technology. With the additional feature of CO2 capture, transport, and storage (here we assume 100 km CO2 transport distance from the plant site) the unit capital cost for CHP-ST and CHP-IGCC technology increases around 70 and 30 percent, respectively. If one considers revenues from trading emission quotas earned through negative emissions one can estimate a market price of CO2 (PC) at which the COE becomes negative (i.e. all capital and operating costs are covered by revenues from heat and negative emissions delivered). Scale effects significantly influence the economic feasibility of CO2 capture. According to the model calculation, the PC at which the COE becomes negative significantly drops from 75 USD/tCO2 for 10 MWe CHP-ST plants to 32 USD/tCO2 for 90 MWe CHP-ST plants when fueled by Salix. The PC drop from 65 USD/tCO2 for 10 MWe CHP-ST plants to 25 USD/tCO2 for 90 MWe CHP-ST plants when fueled by forest/logging residues. For CHP-IGCC plants, the PC decreases from 72.5 USD/tCO2 for 30 MWe to 37.5 USD/tCO2 for 170 MWe when fueled by Salix. When fueled by forest/logging residue, the PC decreases from 62.5 USD/tCO2 for 30 MWe plants to 30 USD/tCO2 for 170 MWe. The techno-economic assessment was based on electrical capacity of the plants and revenues from cogenerated heat and captured CO2 were credited. In practice, the implementation of any cogeneration should be optimized based on site-specific context

Model of European Natural Gas Production, Trade, and Consumption

This working paper represents the first in the series to be published as a description of ongoing activities in the IIASA International Gas Study. Thus, the paper represents a report of one particular task that is nearing completion. The working papers will be presented as individual research activities, although they form only one part of the overail study. This particular paper describes one approach of addressing natural gas production, trade, and use in Europe. For this purpose Europe was divided into five regions in order to distinguish between different endowments with natural gas resources, energy requirements, levels of economic development, and economic infrastructures. The basic objective of the approach was to develop a simple model that can describe future natural gas production, trade, and use on an interactive basis with the analyst. Thus, the model represents a flexible tool that helps identify important issues and questions that could be addressed by other activities within the International Gas Study

A methodology for flexibility analysis of pipeline systems

Pipeline systems serve a crucial role in an effective transport of fluids to the designated location for medium to long span of distances. Owing to its paramount economic significance, pipeline design field have undergone extensive development over the past few years for enhancing the optimization and transport efficiency. This research paper attempts to propose a methodology for flexibility analysis of pipeline systems through employing contemporary computational tools and practices. A methodical procedure is developed, which involves modeling of the selected pipeline system in CAESAR II followed by the insertion of pipe supports and restraints. The specific location and selection of the inserted supports is based on the results derived from the displacement, stress, reaction, and nozzle analysis of the concerned pipeline system. Emphasis is laid on the compliance of the design features to the leading code of pipeline transportation systems for liquid and slurries, ASME B31.4. The discussed procedure and approach can be successfully adjusted for the analysis of various other types of pipeline system configuration. In addition to the provision of systematic flow in analysis, the method also improves efficient time-saving practices in the pipeline stress analysis

Combined Operational Planning of Natural Gas and Electric Power Systems: State of the Art

The growing installation and utilization of natural gas fired power plants (NGFPPs) over the last two decades has lead to increasing interactions between electricity and natural gas (NG) sectors. From 1990 to 2005, the worldwide share of NGFPPs in the power generation mix has almost doubled, from around 10% to nearly 19%; reaching in 2007, for instance, the 54% in Argentina, the 42% in Italy, the 40% in USA, and the 32% in UK (IEA, 2007; IEA, 2009a). The installation of NGFPPs has been driven by technical, economic and environmental reasons. The high thermal efficiency of combined-cycle gas turbine (CCGT) power plants and combined heat and power (CHP) units, their relatively low investment costs, short construction lead time and the prevailing low natural gas prices until 2004 have made NGFPPs more attractive than traditional coal, oil and nuclear power plants, particularly in liberalized electricity markets. Additionally, burning NG has a smaller environmental footprint and a lower carbon emission than any other fossil fuel. Under the light of all conditions previously described, there is a strong and rising interdependency between NG and electricity sectors. In this context, it is essential to include NG system models in electric power systems operation and planning. On the other hand, NG system operation and planning require, as input data, the NG demands of each NGFPPs, which accurately values can only be obtained from the electric power systems dispatch. Therefore, several approaches that address the integrated modeling of electric power and NG systems have been presented. These new approaches contrast with the current models in which both systems are considered in a decoupled manner.Fil: Rubio Barros, Ricardo German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; ArgentinaFil: Ojeda Esteybar, Diego Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; ArgentinaFil: Año, Osvaldo. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; ArgentinaFil: Vargas, Alberto. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; Argentin