A COMPARATIVE STUDY OF DATA-DRIVEN MODELING METHODS FOR SOFT-SENSING IN UNDERGROUND COAL GASIFICATION

Underground coal gasification (UCG) is a technological process, which converts solid coal into a gas in the underground, using injected gasification agents. In the UCG process, a lot of process variables can be measurable with common measuring devices, but there are variables that cannot be measured so easily, e.g., the temperature deep underground. It is also necessary to know the future impact of different control variables on the syngas calorific value in order to support a predictive control. This paper examines the possibility of utilizing Neural Networks, Multivariate Adaptive Regression Splines and Support Vector Regression in order to estimate the UCG process data, i.e., syngas calorific value and underground temperature. It was found that, during the training with the UCG data, the SVR and Gaussian kernel achieved the best results, but, during the prediction, the best result was obtained by the piecewise-cubic type of the MARS model. The analysis was performed on data obtained during an experimental UCG with an ex-situ reactor

APPROACHES TO THE GAS CONTROL IN UCG

Underground Coal Gasification represents an alternative for conventional coal mining. This technology is also less expensive than traditional mining. It is expected that coal will be an important energy source in the coming decades. In requirement to improve the gasification process we must ensure that the combustion reactions generated enough energy to heat the reactants. This can be achieved by controlling the flow of oxidizing agents and the underpressure control at the exit of the reactor UCG. This paper aims to propose the stabilization of air flow as a main gasification agent injected to the gasifier, underground temperature and concentration of O2 in syngas. Also there is proposed the mechanism that could cope with uncertainties in the process of UCG and its control on stabilization level. Paper presents utilization of discrete controller with adaptation in order to stabilization of UCG process variables. The controllers were verified on experimental ex-situ reactor (generator)

CO2 CAPTURE PROJECT - AN INTEGRATED, COLLABORATIVE TECHNOLOGY DEVELOPMENT PROJECT FOR NEXT GENERATION CO2 SEPARATION, CAPTURE AND GEOLOGIC SEQUESTRATION

The CO{sub 2} Capture Project (CCP) is a joint industry project, funded by eight energy companies (BP, ChevronTexaco, EnCana, Eni, Norsk Hydro, Shell, Statoil, and Suncor) and three government agencies (1) European Union (DG Res & DG Tren), (2) Norway (Klimatek) and (3) the U.S.A. (Department of Energy). The project objective is to develop new technologies, which could reduce the cost of CO{sub 2} capture and geologic storage by 50% for retrofit to existing plants and 75% for new-build plants. Technologies are to be developed to ''proof of concept'' stage by the end of 2003. The project budget is approximately $24 million over 3 years and the work program is divided into eight major activity areas: (1) Baseline Design and Cost Estimation--defined the uncontrolled emissions from each facility and estimate the cost of abatement in$/tonne CO{sub 2}. (2) Capture Technology, Post Combustion: technologies, which can remove CO{sub 2} from exhaust gases after combustion. (3) Capture Technology, Oxyfuel: where oxygen is separated from the air and then burned with hydrocarbons to produce an exhaust with high CO{sub 2} for storage. (4) Capture Technology, Pre -Combustion: in which, natural gas and petroleum coke are converted to hydrogen and CO{sub 2} in a reformer/gasifier. (5) Common Economic Model/Technology Screening: analysis and evaluation of each technology applied to the scenarios to provide meaningful and consistent comparison. (6) New Technology Cost Estimation: on a consistent basis with the baseline above, to demonstrate cost reductions. (7) Geologic Storage, Monitoring and Verification (SMV): providing assurance that CO{sub 2} can be safely stored in geologic formations over the long term. (8) Non-Technical: project management, communication of results and a review of current policies and incentives governing CO{sub 2} capture and storage. Technology development work dominated the past six months of the project. Numerous studies are making substantial progress towards their goals. Some technologies are emerging as preferred over others. Pre-combustion Decarbonization (hydrogen fuel) technologies are showing good progress and may be able to meet the CCP's aggressive cost reduction targets for new-build plants. Chemical looping to produce oxygen for oxyfuel combustion shows real promise. As expected, post-combustion technologies are emerging as higher cost options that may have niche roles. Storage, measurement, and verification studies are moving rapidly forward. Hyper-spectral geo-botanical measurements may be an inexpensive and non-intrusive method for long-term monitoring. Modeling studies suggest that primary leakage routes from CO{sub 2} storage sites may be along wellbores in areas disturbed by earlier oil and gas operations. This is good news because old wells are usually mapped and can be repaired during the site preparation process. Many studies are nearing completion or have been completed. Their preliminary results are summarized in the attached report and presented in detail in the attached appendices

Engineered morphologic material structures: physical/chemical properties and applications

Morphologies include the study of shape, size and structure for materials from atomic scale to macroscales. Properties/functions of material structures in general are dependent on morphologies, and tunable properties in chemical and physical can be realized through changing morphologies on surfaces and in bulk systems of materials. For low-dimensional materials, atomic modifications and changes in lattice morphologies can introduce varieties of fascinating phenomena and unconventional intrinsic properties in electric, mechanics chemistry and etc. The reason behind such controllability is that morphological undulation usually is consistent with the mapping of strain, which is related to atomic structures of materials. For micro/macro scale materials, interactions of surface tension, mechanical deformation, etc. dominate the morphological evolution. Structural designs and morphological control can achieve desirable functionalities, for example mechanical flexibility and liquid wettability for practical applications. Herein, strain-engineering strategies including mechanical loading and atomic displacement were applied to modify and control morphologies in materials with different length scales. We firstly investigated the fundamental mechanism of morphological evolution through various load strategies, and relationship between morphologies and the properties of material structures across from nanoscale, microscale to macroscale, including graphene, phosphorene, core-shell microparticles and soft materials/bilayers, etc. Furthermore, we demonstrated to two applications of utilizing designed morphologies, which targeted to figures out challenges in the field of energy conversion and storage to close energy loop. Therefore, we mainly focus on the relation of engineered strategy-morphology-mechanism/property-functional devices in this thesis. Firstly, engineered morphologies in nanomaterials of graphene and phosphorene were investigated through strain-localization, gradient strain, bending/pressing. The effects of surface morphologies on fundamental properties including thermal conductivities, mechanics, electrics, surface energy and chemical reactivities were studied through molecular dynamics (MD) simulations and first-principle calculations combined with experimental verifications: Increased applications of nanoporous graphene in nanoelectronics and membrane separations require ordered and precise perforation of graphene, whose scalablility and time/cost effectiveness represent a significant challenge in existing nanoperforation methods, such as catalytical etching and lithography. We reported a strain-guided perforation of graphene through oxidative etching, where nanopores nucleate selectively at the bulges induced by the pre-patterned nano-protrusions underneath. Using reactive molecular dynamics and theoretical models, we uncover the perforation mechanisms through the relationship between bulge-induced strain and enhanced etching reactivity. Parallel experiments of CVD graphene on SiO2 NPs/ SiO2 substrate verify the feasibility of such strain-guided perforation and evolution of pore size by exposure durations to oxygen plasma. When a nanodroplet is placed on a lattice surface, an inhomogeneous surface strain field perturbs the balance of van der Waals force between the nanodroplet and surface, thus providing a net driving force for nanodroplet motion. Using molecular dynamics and theoretical analysis, we studied the effect of strain gradient on modulating the movement of a nanodroplet. Both modeling and simulation showed that the driving force is opposite to the direction of strain gradient, with a magnitude that is proportional to the strain gradient as well as nanodroplet size. Two representative surfaces, graphene and copper (111) plane, were exemplified to demonstrate the controllable motion of nanodroplet. When the substrate underwent various types of reversible deformations, multiple motion modes of nanodroplets could be feasibly achieved, including acceleration, deceleration and turning, becoming a facile strategy to manipulate nanodroplets along a designed 2D pathway. Using molecular dynamics (MD) simulations, we explored the structural stability and mechanical integrity of phosphorene nanotubes (PNTs), where the intrinsic strain in the tubular PNT structure plays an important role. It was proposed that the atomic structure of larger-diameter armchair PNTs (armPNTs) could remain stable at higher temperature, but the high intrinsic strain in the hoop direction renders zigzag PNTs (zigPNTs) less favorable. The mechanical properties of PNTs, including the Young’s modulus and fracture strength, are sensitive to the diameter, showing a size dependence. A simple model is proposed to express the Young’s modulus as a function of the intrinsic axial strain which in turns depends on the diameter of PNTs. A new phosphorous allotrope, closed-edged bilayer phosphorene nanoribbon, was proposed via radially deforming armchair phosphorene nanotubes. Using molecular dynamics simulations, the transformation pathway from round phosphorene nanotubes falls into two types of collapsed structures: arc-like and sigmoidal bilayer nanoribbons, dependent on the number of phosphorene unit cells. The fabricated nanoribbions are energetically more stable than their parent nanotubes. It was also found via ab initio calculations that the band structure along tube axis substantially changes with the structural transformation. The direct-to-indirect transition of band gap was highlighted when collapsing into the arc-like nanoribbons but not the sigmoidal ones. Furthermore, the band gaps of these two types of nanoribbons showed significant size-dependence of the nanoribbon width, indicative of wider tunability of their electrical properties. Secondly, we studied fundamental mechanisms of generating fascinating surface morphologies on the micro materials/structures of core/shell microsphere driven by surface instability, which is not different those in nanoscale. The island-like dot pattern on spherical substrate were investigated: Through strain-induced morphological instability, protruding patterns of roughly commensurate nanostructures are self-assembled on the surface of spherical core/shell systems. A three-dimensional (3D) phase field model was established for closed substrate. We investigated both numerically and analytically the kinetics of the morphological evolution, from grooves to separated islands which are sensitive to substrate curvature, misfit strain and modulus ratio between core and shell. The faster growth rate of surface undulation was associated with the core/shell system of harder substrate, larger radius or misfit strain. Based on a Ag core/SiO2 shell system, the self-assemblies of SiO2 nano-islands were explored experimentally. The numerical and experimental studies herein could guide the fabrication of ordered quantum structures via surface instability on closed and curved substrates. Up to macroscale material structures, the variety and controllability surface morphologies on soft materials and bilayer films were realized through pre-pattern defects of cavities and in-plane compression. The checkboard and wrinkling surface patterns were observed in different systems through both finite element simulations and 3D printing technique: A rich diversity of surface topologies is controllably engineered by patterning cavities embedded beneath the surface of soft materials. Upon external compression, the surface undergoes the reversible transformation from the flat surface to various surface topographies, including the periodic checkerboard pattern with alternatively convex and concave features. To design the surface features, both 2D and 3D finite element based-simulations were performed. It was demonstrated that the periodic surface features with controllable morphology, such as 1D waves, checkerboard pattern and mutually perpendicular apexes, etc. can be realized through varying cavity geometries (e.g., relative inter-cavity distance, shapes and biaxial/uniaxial load). Based on 3D printed prototypes, we further conducted experiments to validate the simulation results of 2D morphologies. The patterned cavities in soft materials made designing a variety of reversible surface features possible, offering an effective fabrication approach for wide application across multiple scales. Wrinkle formation followed by sharp strain localization is commonly observed in compressed stiff film/soft substrate systems. However, cavities or defects beneath the film may directly trigger the formation of local ridges and then folding configurations at a relatively small compressive strain, and a mixture of wrinkles and folds upon further compression. The morphological transition is different than those of defect-free substrates. Numerical simulations of continuously compressed bilayer with pre-patterned cavities were carried out to elucidate the transition mechanism of surface patterns. Parallel experiments of cavities-patterned bilayer prototypes by 3D-printing were also performed to validate the findings in simulations. A rich diversity of periodic surface topologies, including overall spreading waves, localizations, saw-like and co-existing features of folds and wrinkles can be obtained by varying the diameter, depth and spacing of cavities, which provides a potential approach to engineer various surface patterns for applications. Since these discussed material structures are promising candidates for energy/environmental applications, two device-level functional systems/products here utilize intriguing morphologies in both nanoscale and macroscale. To close energy loop, the energy conversion reactor (chemical loop reduction of CO2) and the energy storage device (flexible lithium ion battery) were demonstrated: We reported an effective reduction method for splitting air-containing CO2 into CO for high-value chemicals, through a chemical looping redox scheme with Cu-doped LaFeO3 perovskites as efficient oxygen carriers for splitting CO2 with a high-concentration of O2 (e.g. 1:5 O2/CO2 molar ratio, mimicking 1:1 CO2/air mixture). Up to 2.28 mol/kg CO yield was achieved with good stability in the CO2 splitter, five times higher than that with the conventional pristine LaFeO3 perovskite. Through ab initio calculations, we uncovered that the exsolution of metallic Cu on the surface of reduced perovskite is capable of mitigating the competition between CO2 and O2 for the re-oxidation step. This air-stable and scalable scheme can economically integrate with upstream DAC and downstream gas-to-liquids plants, exhibiting up to 94.5% and 42.8% reduction in net CO2 emission for valuable chemicals production (methanol and acetic acid) when compared with the coal gasifier-based route and this redox scheme using pure CO2, respectively. Flexible batteries, seamlessly compatible with flexible and wearable electronics, attract a great deal of research attention. Current designs of flexible batteries are unable to meet one of the most extreme yet common deformation scenarios in practice, folding, while retaining high energy density. Inspired by origami folding, we proposed a novel strategy to fabricate zigzag-like lithium ion batteries with superior foldability. The battery structure could approach zero-gap between two adjacent energy storage segments, achieving an energy density that is 96.4% of that in a conventional stacking cell. A foldable battery thus fabricated demonstrated an energy density of 275 Wh L-1 and was resilient to fatigue over 45,000 dynamic cycles with a folding angle of 130°, while retaining stable electrochemical performance. Additionally, the power stability and resilience to nail shorting of the foldable battery were also examined

Advanced Technologies for Biomass

The use of biomass and organic waste material as a primary resource for the production of fuels, chemicals, and electric power is of growing significance in light of the environmental issues associated with the use of fossil fuels. For this reason, it is vital that new and more efficient technologies for the conversion of biomass are investigated and developed. Today, various advanced methods can be used for the conversion of biomass. These methods are broadly classified into thermochemical conversion, biochemical conversion, and electrochemical conversion. This book collects papers that consider various aspects of sustainability in the conversion of biomass into valuable products, covering all the technical stages from biomass production to residue management. In particular, it focuses on experimental and simulation studies aiming to investigate new processes and technologies on the industrial, pilot, and bench scales

Biomass for Energy Country Specific Show Case Studies

In many domestic and industrial processes, vast percentages of primary energy are produced by the combustion of fossil fuels. Apart from diminishing the source of fossil fuels and the increasing risk of higher costs and energy security, the impact on the environment is worsening continually. Renewables are becoming very popular, but are, at present, more expensive than fossil fuels, especially photovoltaics and hydropower. Biomass is one of the most established and common sources of fuel known to mankind, and has been in continuous use for domestic heating and cooking over the years, especially in poorer communities. The use of biomass to produce electricity is interesting and is gaining ground. There are several ways to produce electricity from biomass. Steam and gas turbine technology is well established but requires temperatures in excess of 250 °C to work effectively. The organic Rankine cycle (ORC), where low-boiling-point organic solutions can be used to tailor the appropriate solution, is particularly successful for relatively low temperature heat sources, such as waste heat from coal, gas and biomass burners. Other relatively recent technologies have become more visible, such as the Stirling engine and thermo-electric generators are particularly useful for small power production. However, the uptake of renewables in general, and biomass in particular, is still considered somewhat risky due to the lack of best practice examples to demonstrate how efficient the technology is today. Hence, the call for this Special Issue, focusing on country files, so that different nations’ experiences can be shared and best practices can be published, is warranted. This is realistic, as it seems that some nations have different attitudes to biomass, perhaps due to resource availability, or the technology needed to utilize biomass. Therefore, I suggest that we go forward with this theme, and encourage scientists and engineers who are researching in this field to present case studies related to different countries. I certainly have one case study for the UK to present

Energy, Science and Technology 2015. The energy conference for scientists and researchers. Book of Abstracts, EST, Energy Science Technology, International Conference & Exhibition, 20-22 May 2015, Karlsruhe, Germany

We are pleased to present you this Book of Abstracts, which contains the submitted contributions to the "Energy, Science and Technology Conference & Exhibition EST 2015". The EST 2015 took place from May, 20th until May, 22nd 2015 in Karlsruhe, Germany, and brought together many different stakeholders, who do research or work in the broad field of "Energy". Renewable energies have to present a relevant share in a sustainable energy system and energy efficiency has to guarantee that conventional as well as renewable energy sources are transformed and used in a reasonable way. The adaption of existing infrastructure and the establishment of new systems, storages and grids are necessary to face the challenges of a changing energy sector. Those three main topics have been the fundament of the EST 2015, which served as a platform for national and international attendees to discuss and interconnect the various disciplines within energy research and energy business. We thank the authors, who summarised their high-quality and important results and experiences within one-paged abstracts and made the conference and this book possible. The abstracts of this book have been peer-reviewed by an international Scientific Programme Committee and are ordered by type of presentation (oral or poster) and topics. You can navigate by using either the table of contents (page 3) or the conference programme (starting page 4 for oral presentations and page 21 for posters respectively)

Energy. A continuing bibliography with indexes, issue 18

This issue of Energy lists 1038 reports, journal articles, and other documents announced between April 1, 1978 and June 30, 1978 in Scientific and Technical Aerospace Reports (STAR) or in International Aerospace Abstracts (IAA). The coverage includes regional, national and international energy systems; research and development on fuels and other sources of energy; energy conversion, transport, transmission, distribution and storage, with special emphasis on use of hydrogen and of solar energy. Also included are methods of locating or using new energy resources. Of special interest is energy for heating, lighting, for powering aircraft, surface vehicles, or other machinery