There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

Global warming and climate change concerns have triggered global efforts to reduce the concentration of atmospheric carbon dioxide (CO2). Carbon dioxide capture and storage (CCS) is considered a crucial strategy for meeting CO2 emission reduction targets. In this paper, various aspects of CCS are reviewed and discussed including the state of the art technologies for CO2 capture, separation, transport, storage, leakage, monitoring, and life cycle analysis. The selection of specific CO2 capture technology heavily depends on the type of CO2 generating plant and fuel used. Among those CO2 separation processes, absorption is the most mature and commonly adopted due to its higher efficiency and lower cost. Pipeline is considered to be the most viable solution for large volume of CO2 transport. Among those geological formations for CO2 storage, enhanced oil recovery is mature and has been practiced for many years but its economical viability for anthropogenic sources needs to be demonstrated. There are growing interests in CO2 storage in saline aquifers due to their enormous potential storage capacity and several projects are in the pipeline for demonstration of its viability. There are multiple hurdles to CCS deployment including the absence of a clear business case for CCS investment and the absence of robust economic incentives to support the additional high capital and operating costs of the whole CCS process.

https://www.elsevier.com/__data/assets/pdf_file/0005/96980/Current-status-carbon-capture.pdf

An overview of current status of carbon dioxide capture and storage technologies

Dihydrogen, methane, and carbon dioxide isotherm measurements were performed at 1−85 bar and 77−298 K on the evacuated forms of seven porous covalent organic frameworks (COFs). The uptake behavior and capacity of the COFs is best described by classifying them into three groups based on their structural dimensions and corresponding pore sizes. Group 1 consists of 2D structures with 1D small pores (9 A for each of COF-1 and COF-6), group 2 includes 2D structures with large 1D pores (27, 16, and 32 A for COF-5, COF-8, and COF-10, respectively), and group 3 is comprised of 3D structures with 3D medium-sized pores (12 A for each of COF-102 and COF-103). Group 3 COFs outperform group 1 and 2 COFs, and rival the best metal−organic frameworks and other porous materials in their uptake capacities. This is exemplified by the excess gas uptake of COF-102 at 35 bar (72 mg g−1 at 77 K for hydrogen, 187 mg g−1 at 298 K for methane, and 1180 mg g−1 at 298 K for carbon dioxide), which is similar to the performance of COF...

http://yaghi.berkeley.edu/pdfPublications/Furukawa09.pdf

Storage of Hydrogen, Methane, and Carbon Dioxide in Highly Porous Covalent Organic Frameworks for Clean Energy Applications

Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

/pdf/carbon-capture-and-storage-ccs-the-way-forward-11rgsqyer0.pdf

Carbon capture and storage (CCS): the way forward

Part 1 Introduction: classification and significance. Part 2 Fundamentals: hydrodynamics of co-current upward fluidized bed systems mass transfer, mixing and heat transfer of co-current upward fluidized bed systems slurry bubble column systems countercurrent and liquid-batch fluidized bed systems miscellaneous systems. Part 3 Applications: fermentation aerobic biological wastewater treatment flue gas desulphurization and particulate removal hydrotreating and conversion of resids miscellaneous systems.

Gas-liquid-solid fluidization engineering

Part I Basic Relationships: 1 Size and properties of particles 2 Collision mechanics of solids 3 Momentum transfer and charge transfer 4 Basic heat and mass transfer 5 Basic equations 6 Intrinsic phenomena in a gas-solid flow Part II System Characteristics: 7 Gas-solid separation 8 Hopper and stand pipe flows 9 Dense-phase fluidized beds 10 Circulating fluidized beds 11 Pneumatic conveying of solids 12 Heat and mass transfer phenomena in fluidization systems Appendix Summary of scalar, vector, and tensor notations

Principles of gas-solid flows

CO2 mineral sequestration: physically activated dissolution of serpentine and pH swing process

Preface. 1 Introduction. 1.1 Background. 1.1.1 Renewable Energy. 1.1.2 Fossil Energy Outlook. 1.2 Coal Combustion. 1.2.1 Energy Conversion Efficiency Improvement. 1.2.2 Flue Gas Pollutant Control Methods. 1.3 CO2 Capture. 1.4 CO2 Sequestration. 1.5 Coal Gasification. 1.6 Chemical Looping Concepts. 1.7 Chemical Looping Processes. 1.8 Overview of This Book. References. 2 Chemical Looping Particles. 2.1 Introduction. 2.2 Type I Chemical Looping System. 2.2.1 General Particle Characteristics. 2.2.2 Thermodynamics and Phase Equilibrium of Metals and Metal Oxides. 2.2.3 Particle Regeneration with Steam. 2.2.4 Reaction with Oxygen and Heat of Reaction. 2.2.5 Particle Design Considering Heat of Reaction. 2.2.6 Particle Preparation and Recyclability. 2.2.7 Particle Formulation and Effect of Support. 2.2.8 Effect of Particle Size and Mechanical Strength. 2.2.9 Carbon and Sulfur Formation Resistance. 2.2.10 Particle Reaction Mechanism. 2.2.11 Effect of Reactor Design and Gas-Solid Contact Modes.7 2.2.12 Selection of Primary Metal for Chemical Looping Combustion of Coal. 2.3 Type II Chemical Looping System. 2.3.1 Types of Metal Oxide. 2.3.2 Thermodynamics and Phase Equilibrium of Metal Oxide and Metal Carbonate. 2.3.3 Reaction Characteristics of Ca-Based Sorbents for CO2 Capture. 2.3.4 Synthesis of the High-Reactivity PCC-CaO Sorbent. 2.3.5 Reactivity of Calcium Sorbents. 2.3.6 Recyclability of Calcium Oxides. 2.4 Concluding Remarks. References. 3 Chemical Looping Combustion. 3.1 Introduction. 3.2 CO2 Capture Strategies for Fossil Fuel Combustion Power Plants. 3.2.1 Pulverized Coal Combustion Power Plants. 3.2.2 CO2 Capture Strategies. 3.3 Chemical Looping Combustion. 3.3.1 Particle Reactive Properties and Their Relationship with CLC Operation. 3.3.2 Key Design and Operational Parameters for a CFB-Based CLC System. 3.3.3 CLC Reactor System Design. 3.3.4 Gaseous Fuel CLC Systems and Operational Results. 3.3.5 Solid Fuel CLC Systems and Operational Results. 3.4 Concluding Remarks. References. 4 Chemical Looping Gasification Using Gaseous Fuels. 4.1 Introduction. 4.2 Traditional Coal Gasification Processes. 4.2.1 Electricity Production-Integrated Gasification Combined Cycle (IGCC). 4.2.2 H2 Production. 4.2.3 Liquid Fuel Production. 4.3 Iron-Based Chemical Looping Processes Using Gaseous Fuels. 4.3.1 Lane Process and Messerschmitt Process. 4.3.2 U.S. Bureau of Mines Pressurized Fluidized Bed Steam-Iron Process. 4.3.3 Institute of Gas Technology Process. 4.3.4 Syngas Chemical Looping (SCL) Process. 4.4 Design, Analysis and Optimization of the Syngas Chemical Looping (SCL) Process. 4.4.1 Thermodynamic Analyses of SCL Reactor Behavior. 4.4.2 ASPEN PLUS Simulation of SCL Reactor Systems. 4.4.3 Syngas Chemical Looping (SCL) Process Testing. 4.5 Process Simulation of the Traditional Gasification Process and the Syngas Chemical Looping Process. 4.5.1 Common Assumptions and Model Setup. 4.5.2 Description of Various Systems. 4.5.3 ASPEN PLUS Simulation, Results, and Analyses. 4.6 Example of SCL Applications-A Coal-to-Liquid Confi guration. 4.6.1 Process Overview. 4.6.2 Mass/Energy Balance and Process Evaluation. 4.7 Calcium Looping Process Using Gaseous Fuels. 4.7.1 Description of the Processes. 4.7.2 Reaction Characteristics of the Processes. 4.7.3 Analyses of the Processes. 4.7.4 Enhanced Coal-to-Liquid (CTL) Process with Sulfur and CO2 Capture. 4.8 Concluding Remarks. References. 5 Chemical Looping Gasification Using Solid Fuels. 5.1 Introduction. 5.2 Chemical Looping Gasification Processes Using Calcium-Based Sorbent. 5.2.1 CO2 Acceptor Process. 5.2.2 HyPr-Ring Process. 5.2.3 Zero Emission Coal Alliance Process. 5.2.4 ALSTOM Hybrid Combustion-Gasification Process. 5.2.5 Fuel-Flexible Advanced Gasification-Combustion Process. 5.2.6 General Comments. 5.3 Coal-Direct Chemical Looping (CDCL) Processes Using Iron-Based Oxygen Carriers. 5.3.1 Coal-Direct Chemical Looping Process-Configuration I. 5.3.2 Coal-Direct Chemical Looping Process-Configuration II. 5.3.3 Comments on the Iron-Based Coal-Direct Chemical Looping Process. 5.4 Challenges to the Coal-Direct Chemical Looping Processes and Strategy for Improvements. 5.4.1 Oxygen-Carrier Particle Reactivity and Char Reaction Enhancement. 5.4.2 Configurations and Conversions of the Reducer. 5.4.3 Performance of the Oxidizer and the Combustor. 5.4.4 Fate of Pollutants and Ash. 5.4.5 Energy Management, Heat Integration, and General Comments. 5.5 Process Simulation on the Coal-Direct Chemical Looping Process. 5.5.1 ASPEN Model Setup. 5.5.2 Simulation Results. 5.6 Concluding Remarks. References. 6 Novel Applications of Chemical Looping Technologies. 6.1 Introduction. 6.2 Hydrogen Storage and Onboard Hydrogen Production. 6.2.1 Compressed Hydrogen Gas and Liquefi ed Hydrogen. 6.2.2 Metal Hydrides. 6.2.3 Bridged Metal-Organic Frameworks. 6.2.4 Carbon Nanotubes and Graphite Nanofibers. 6.2.5 Onboard Hydrogen Production via Iron Based Materials. 6.3 Carbonation-Calcination Reaction (CCR) Process for Carbon Dioxide Capture. 6.4 Chemical Looping Gasification Integrated with Fuel Cells. 6.4.1 Chemical Looping Gasification Integrated with Solid-Oxide Fuel Cells. 6.4.2 Direct Solid Fuel Cells. 6.5 Enhanced Steam Methane Reforming. 6.6 Tar Sand Digestion via Steam Generation. 6.7 Liquid Fuel Production from Chemical Looping Gasification. 6.8 Chemical Looping with Oxygen Uncoupling (CLOU). 6.9 Concluding Remarks. References. Subject Index. Author Index.

Chemical Looping Systems for Fossil Energy Conversions

Biomass is a promising renewable energy resource despite its low energy density, high moisture content and complex ash components The use of biomass in energy production is considered to be approximately carbon neutral, and if it is combined with carbon capture technology, the overall energy conversion may even be negative in terms of net CO2 emission, which is known as BECCS (bioenergy with carbon capture and storage) The initial development of BECCS technologies often proposes the installation of a CO2 capture unit downstream of the conventional thermochemical conversion processes, which comprise combustion, pyrolysis or gasification Although these approaches would benefit from the adaptation of already well developed energy conversion processes and CO2 capture technologies, they are limited in terms of materials and energy integration as well as systems engineering, which could lead to truly disruptive technologies for BECCS Recently, a new generation of transformative energy conversion technologies including chemical looping have been developed In particular, chemical looping employs solid looping materials and it uniquely allows inherent capture of CO2 during the conversion of fuels In this review, the benefits, challenges, and prospects of biomass-based chemical looping technologies in various configurations have been discussed in-depth to provide important insight into the development of innovative BECCS technologies based on chemical looping

/pdf/biomass-based-chemical-looping-technologies-the-good-the-bad-4tm6q6d23h.pdf

Liang-Shih Fan

Papers

Gas-liquid-solid fluidization engineering

Principles of gas-solid flows

CO2 mineral sequestration: physically activated dissolution of serpentine and pH swing process

Chemical Looping Systems for Fossil Energy Conversions

Biomass-based chemical looping technologies: the good, the bad and the future